Bispectral index for improving anaesthetic delivery and postoperative recovery
References
References to studies included in this review
References to studies excluded from this review
References to studies awaiting assessment
Additional references
References to other published versions of this review
Characteristics of studies
Characteristics of included studies [ordered by study ID]
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| Methods | RCT | |
| Participants | Country: USA | |
| Interventions |
| |
| Outcomes | Successful fast track rate (using modified Aldrete Score, main outcome) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information about the sequence generation process |
| Allocation concealment (selection bias) | Low risk | "...99 patients...were enrolled and randomised, using a closed envelope technique with random numbers,..." |
| Incomplete outcome data (attrition bias) | Low risk | "...2 patients required inpatient hospitalisation postoperatively for surgical complications and were withdrawn from the final analysis." Plausible effect size (difference in means) among missing outcomes not enough to have a clinically relevant impact on observed effect size |
| Selective reporting (reporting bias) | Low risk | All expected outcomes have been reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In the BIS‐monitored group, sevoflurane was titrated to maintain the BIS value in the 50‐60 range...." This indicates no blinding of the anaesthesia provider |
| Blinding of outcome assessors? | Unclear risk | The study has not mentioned outcome assessor blinding |
| Methods | RCT | |
| Participants | Country: USA Exclusion: a history of any disabling central nervous or cerebrovascular disease, hypersensitivity to opioids or substance abuse, treatment with opioids or any psychoactive medication, or a body weight 70% or more than 130% of ideal body weight | |
| Interventions |
| |
| Outcomes | Sevoflurane consumption (gm/kg/hr) (primary outcome) Recovery times (min) ‐ time to spontaneous eye opening ‐ time to tracheal extubation Sufentanil consumption (µg/kg/hr) Intraoperative recall by using a standardized interview (Cn, %) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "...140 adult patients were randomly allocated to one of three groups, the standard practice group, the BIS‐guided group, or the spectral entropy‐guided group, using a randomization list performed with computer‐generated random numbers." |
| Allocation concealment (selection bias) | Unclear risk | No mention about allocation concealment |
| Incomplete outcome data (attrition bias) | Unclear risk | "Six patients were excluded from the standard practice group (1 was not extubated at the end of surgery because of hypothermia, 3 required intraoperative propofol administration, and there were missing data in 2 cases), six patients were excluded from the BIS‐guided group (3 were not extubated at the end of surgery because of hypothermia, 2 required intraoperative propofol administration, and monitor data were lost in 1 case) and three from the spectral entropy‐guided group (all were not extubated at the end of surgery due to hypothermia, 2 required intraoperative propofol administration) (ns)." The study has not clearly stated how to deal with these excluded patients |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In both EEG‐groups, anaesthesiologists were instructed to adjust the sevoflurane concentration to keep BIS, SE, and RE values, in the respective group, in the range of 40‐60. ." It was unlikely to blind the anaesthesia providers |
| Blinding of outcome assessors? | Unclear risk | Insufficient information |
| Methods | Quasi‐randomization | |
| Participants | Country: Spain | |
| Interventions |
| |
| Outcomes | Propofol consumption | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | High risk | The study used sequential randomization (quasi‐randomization). The rational for this 'sequence' was to avoid any contamination or influence of the 'BIS guided anaesthesia' on the 'standard anaesthesia' administered subsequently |
| Allocation concealment (selection bias) | High risk | The allocation concealment was not used |
| Incomplete outcome data (attrition bias) | Low risk | One in the control group was excluded from the analysis. Plausible effect size (difference in means) among missing outcomes not enough to have a clinically relevant impact on observed effect size |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | Insufficient information |
| Blinding of patients? | Low risk | The patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "Anesthesia administered guided by BIS monitor." (Ivan Sola, translator) |
| Blinding of outcome assessors? | Unclear risk | Insufficient information |
| Methods | RCT | |
| Participants | Country: Sweden | |
| Interventions |
| |
| Outcomes | Sevoflurane consumption (g/min) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | No detailed information regarding the sequence generation process |
| Allocation concealment (selection bias) | Unclear risk | No detailed information regarding allocation concealment |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information regarding withdrawals/dropouts |
| Selective reporting (reporting bias) | Low risk | All expected outcomes have been reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "...sevoflurane was titrated to maintain a target BIS of 60 during surgery." This indicates no blinding of the anaesthesia care provider |
| Blinding of outcome assessors? | Unclear risk | No detailed information regarding blinding of outcomes assessors |
| Methods | RCT, multicentre | |
| Participants | Country: USA | |
| Interventions |
| |
| Outcomes | Definite intraoperative awareness (Cn, %) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | ".... in which 2000 patients underwent prerandomization electronically in blocks of 100, with 50 patients assigned to a BIS‐guided protocol and 50 to an ETAG‐guided protocol." This indicates adequate sequence generation |
| Allocation concealment (selection bias) | Low risk | The design was a single‐centre, prospective study, in which 2000 patients underwent prerandomization electronically in blocks of 100, with 50 patients assigned to a BIS‐guided protocol and 50 to an ETAG‐guided protocol |
| Incomplete outcome data (attrition bias) | Low risk | Table 2 of the study shows 33 in the BIS group and 20 in the ETAG group were excluded. Intention‐to‐treat analysis was planned |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | "The anaesthesia practitioners were aware of the assignments of the patients, but the patients, the postoperative interviewers, the expert reviewers, and the statistician were not." |
| Blinding of anaesthesiologists? | High risk | "The anaesthesia practitioners were aware of the assignments of the patients, but the patients, the postoperative interviewers, the expert reviewers, and the statistician were not." |
| Blinding of outcome assessors? | Low risk | "The anaesthesia practitioners were aware of the assignments of the patients, but the patients, the postoperative interviewers, the expert reviewers, and the statistician were not." |
| Methods | RCT, multicentre | |
| Participants | Country: USA | |
| Interventions |
| |
| Outcomes | Definite intraoperative awareness (Cn, %) using Michigan Awareness Classification Instrument | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "...6100 prerandomization designations were generated electronically in blocks of 100, divided equally between the groups." |
| Allocation concealment (selection bias) | Low risk | " Labels indicating BIS group to EATC group were sealed in opaque, number envelopes |
| Incomplete outcome data (attrition bias) | Low risk | 46 in the BIS group and 50 in the EATC group were lost to follow up. A modified intention‐to‐treat analysis were performed |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | "The anaesthesia practitioners were aware of the assignments of the patients, but the patients, the postoperative interviewers, the expert reviewers, and the statistician were not." |
| Blinding of anaesthesiologists? | High risk | "The anaesthesia practitioners were aware of the assignments of the patients, but the patients, the postoperative interviewers, the expert reviewers, and the statistician were not." |
| Blinding of outcome assessors? | Low risk | "The anaesthesia practitioners were aware of the assignments of the patients, but the patients, the postoperative interviewers, the expert reviewers, and the statistician were not." |
| Methods | RCT | |
| Participants | Country: Turkey | |
| Interventions |
| |
| Outcomes | Mean sevoflurane exposure (aged adjusted minimal alveolar concentration, main outcome) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information about the sequence generation process |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information regarding withdrawals/dropouts |
| Selective reporting (reporting bias) | Low risk | All expected outcomes were reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "..the anaesthesiologist had access to the monitor and adjusted the concentration of sevoflurane to achieve a target BIS in the range of 40‐60." This indicates no blinding of the anaesthesia care provider |
| Blinding of outcome assessors? | Unclear risk | The author did not mention about blinding of the outcome assessors |
| Methods | RCT | |
| Participants | Turkey | |
| Interventions |
| |
| Outcomes | Average end tidal concentrations (mean±SD) of sevoflurane | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | A computer‐generated sequence of number was used |
| Allocation concealment (selection bias) | Low risk | A sealed envelope technique was used |
| Incomplete outcome data (attrition bias) | Unclear risk | "Three patients were excluded from the study due to disconnection of BIS probe (2) or artefact contamination (1)." The study has not been mentioned how to deal with the missing outcome data in the analysis |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "...sevoflurane was adjusted in an effort to achieve a target BIS of 40‐60..." This indicates no blinding of the anaesthesia provider |
| Blinding of outcome assessors? | Unclear risk | The study has not mentioned clearly about the blinding of outcomes assessors |
| Methods | RCT, multicentre | |
| Participants | Country: Germany | |
| Interventions |
| |
| Outcomes | Desflurane consumption (end tidal concentrations) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "After enrolment the patients were randomized by drawing lots from a closed box |
| Allocation concealment (selection bias) | Unclear risk | No mention about method of allocation concealment |
| Incomplete outcome data (attrition bias) | Unclear risk | No detailed information |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | Patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | ".. desflurane was sequentially adjusted according to the predetermined target values of BIS or AAI, or clinical parameters." The blinding of anaesthesia care providers is unlikely |
| Blinding of outcome assessors? | Low risk | "Recovery times were recorded by a blinded investigator." This indicates blinding of the outcome assessors |
| Methods | RCT | |
| Participants | Country: Malaysia | |
| Interventions |
| |
| Outcomes | ‐Propofol requirement during cardiopulmonary bypass | |
| Notes | ‐Both arms were conducted during cardiopulmonary bypass | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Patients were randomly allocated by computer generated random numbers in closed envelopes." |
| Allocation concealment (selection bias) | Low risk | Patients were randomly allocated by computer‐generated random numbers in closed envelopes |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially introduce 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In group B, BIS‐controlled adjustment of the propofol infusion was used to achieve a BIS value of 40 to 50." This indicates no blinding of the anaesthesia care provider |
| Blinding of outcome assessors? | Unclear risk | Insufficient information |
| Methods | RCT | |
| Participants | Country: Germany Operation: minor surgery expected to last at least one hour (orthopaedic patients receiving regional anaesthesia for intra‐ and postoperative pain control for surgery to the upper or lower extremity in combination with general anaesthesia) Duration of anaesthesia: 100±30.7, 123.7±44.6, 119.5±50.6 (min) | |
| Interventions | 1. Propofol guided by BIS (A‐2000 BIS® monitor (version XP, software version 4.0), Target BIS=50 2.Propofol guided by Entropy (an Entropy Module®), Target entropy=50 3. Propofol guided by clinical parameters (blood pressure, heart rate, sweating, tear production, movement) | |
| Outcomes | ‐drug consumption ‐recovery times ‐intraoperative recall awareness | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Patients were randomized by drawing lots from a closed box |
| Allocation concealment (selection bias) | Unclear risk | No information regarding concealed randomization |
| Incomplete outcome data (attrition bias) | Unclear risk | Due to insufficient regional anaesthesia or EEG data loss, five patients in the entropy group and three patients in each of the BIS and standard practice groups had to be excluded from further investigation |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially introduce 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "Propofol was sequentially adjusted according to the predetermined target values of BIS or Entropy (SE) or clinical parameters." |
| Blinding of outcome assessors? | Unclear risk | No information |
| Methods | RCT, multicentre | |
| Participants | Country: USA | |
| Interventions |
| |
| Outcomes | ‐Normalized propofol infusion rate (µg/kg/hr) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "The sequence of treatments was determined in blocks of 10 using a random number generator." |
| Allocation concealment (selection bias) | Low risk | "Assignment to the study condition was determined using sequential coded envelopes." |
| Incomplete outcome data (attrition bias) | Unclear risk | "Twenty‐eight patients were excluded from efficacy analysis due to protocol violations for various reasons." As a result, there were 125 CS and 115 BIS group patients. There is uncertainty how much these missing outcome data could affect the observed effect size |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "The anaesthesiologists viewed the monitor in the BIS treatment group." This indicate no blinding of the anaesthesia providers |
| Blinding of outcome assessors? | Low risk | "Patients were assessed continuously by a recovery room nurse who blinded to the intraoperative treatment group assignment." This indicates blinding of the assessor for the main outcome |
| Methods | RCT | |
| Participants | Country: Spain | |
| Interventions |
| |
| Outcomes | ‐Total dose of fentanyl during maintenance (main outcome) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Using random numbers table |
| Allocation concealment (selection bias) | Unclear risk | No mention about the allocation concealment |
| Incomplete outcome data (attrition bias) | Low risk | All patients included in the analysis |
| Selective reporting (reporting bias) | Low risk | All expected outcomes have been reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | Patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | According to Ivan Sola (translator) "The propofol perfusion was controlled on depending of the BIS values to maintain patients' values between 40 and 60". This indicates no blinding of the anaesthesia care providers |
| Blinding of outcome assessors? | Low risk | According to Ivan Sola (translator) ".. Nurse on the PACU assessed blinded the patients' self reported pain level' |
| Methods | RCT | |
| Participants | Participants country: Saudi Arabia N = 30 ASA: I/II 8/7, 10/5 Morbidity obese: body‐mass index of greater than 35 Gender: male/female 9/6, 11/4 Age: 39± 4.50, 41.21± 5.07 years Exclusion: renal, hepatic or neurological dysfunction or use of benzodiazepines, anticonvulsants, alcohol, opioids or other psychotropic drugs Operation: gastric banding procedures Duration of anaesthesia: 136.6±113.7, 138.9±13.8 minutes | |
| Interventions | 1) Sevoflurane administration guided by BIS (BIS A‐2000 software 2.21, Aspect Medical Systems, Newton, and Mass), BIS value of 40‐60 during maintenance (BIS group), Cn = 15 2) Sevoflurane administration guided by signs of inadequate anaesthesia (increased blood pressure of greater than 20%, increased heart rate of greater than 90 beats per minutes and other somatic responses) (CS group), Cn = 15 | |
| Outcomes | Sevoflurane used during maintenance (ml/hr) Recovery times (min) ‐time to awakening (opening eyes on verbal command) ‐time to extubation ‐time to Aldrete score of 9 | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information about the allocation concealment |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficiet information regarding withdrawal/dropouts |
| Selective reporting (reporting bias) | Low risk | All expected outcome reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "Group BIS: the anaesthesiologist had access the monitor.." This indicates no blinding of the anaesthesia care provider |
| Blinding of outcome assessors? | Low risk | "Blinded study personnel recorded the time ...." This is blinding of outcomes assessors |
| Methods | RCT | |
| Participants | Country: Egypt Anaesthesia: propofol induction, atracurium, sevoflurane, nitrous in oxygen, fentanyl | |
| Interventions | 1) Sevoflurane administration guided by BIS (Aspect Medical Systems, model A‐2000,Newton, MA, USA), Maintenance BIS :50‐60, end of surgery BIS 55‐70 2) Sevoflurane or fentanyl administration guided by clinical signs (mean arterial blood pressure > 25 above baseline >25% above baseline or heart rate > 90 beats per minutes) or labetalol based on anaesthesiologist's discretion | |
| Outcomes | ‐recovery times ‐anaesthetic drug consumption ‐amount of sevoflurane (ml) ‐end tidal sevoflurane concentration ‐incidence of awareness | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Patients were randomly selected and assigned into two groups of 30 patients each |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information about the allocation concealment |
| Incomplete outcome data (attrition bias) | Unclear risk | Three patients were discarded, two from BIS‐b group and one from BIS‐g group |
| Selective reporting (reporting bias) | Low risk | All expected outcome reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "exhibited hypertension or tachycardia the mode of treatment was dependent on the BIS index" |
| Blinding of outcome assessors? | Low risk | "...Aldrete score assessment is expressed in Table 1 and performed at 15 min interval by a research assistant blinded to group assignment..." |
| Methods | RCT | |
| Participants | Country: Germany | |
| Interventions |
| |
| Outcomes | ‐Normalized propofol infusion rate (µg/kg/hr) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | ".. patients were randomized by drawing lots from a closed box." |
| Allocation concealment (selection bias) | Low risk | ".. patients were randomized by drawing lots from a closed box." |
| Incomplete outcome data (attrition bias) | Unclear risk | The study has not mentioned about the withdrawal/dropouts |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "..Propofol TCI during maintenance of anaesthesia was continuously adjusted according to a target value of.......50 for BIS.". This indicates no blinding of anaesthesia care providers |
| Blinding of outcome assessors? | Low risk | "Recovery times and propofol consumption were recorded by a blinded investigator." |
| Methods | RCT | |
| Participants | Country: Germany | |
| Interventions |
| |
| Outcomes | Outcomes ‐ desflurane consumption (mg/min) | |
| Notes | . | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | ".. patients were randomized by drawing lots from a closed box." |
| Allocation concealment (selection bias) | Low risk | ".. patients were randomized by drawing lots from a closed box." |
| Incomplete outcome data (attrition bias) | Unclear risk | The study has not mentioned about the withdrawal/dropouts |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "..desflurane during maintenance of anaesthesia was continuously adjusted according to a target value of.......50 for BIS ". This indicates no blinding of anaesthesia care providers |
| Blinding of outcome assessors? | Low risk | "Recovery times were recorded by a blinded investigator." |
| Methods | RCT, multicentre | |
| Participants | Country: Australia N = 2463 ASA: I/II/III/IV 111/179/542/388/5, 127/227/520/354/10 Gender: Male/Female 752/473, 784/454 Age: 58.1 (16.5), 57.5 (16.9) years Inclusion : at least one of risk factors for awareness, i.e. caesarean section, high risk cardiac surgery, acute trauma with hypovolaemia, rigid bronchoscopy, significant impairment of cardiovascular status, severe end stage lung disease, past history of awareness, unplanned awake intubation, known or suspected heavy alcohol intake, chronic benzodiazepine or opioid use , or current protease inhibitor therapy Operation: minor/intermediate/major 104/216/905, 104/231/903 Duration of anaesthesia: 3.2 (1.5‐4.4), 3.1 ( 1.3‐4.5) hours | |
| Interventions |
| |
| Outcomes | ‐Confirmed awareness (Cn, %) ‐Recovery times* | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | A computer‐generated random group allocation |
| Allocation concealment (selection bias) | Low risk | A central allocation |
| Incomplete outcome data (attrition bias) | Low risk | " ..40 patients were withdrawn because of cancellation of surgery ( BIS group13, routine group13), withdrawal of consent ( six, twoO, surgery done without general anaesthesia ( four, none), or the patients was under‐age (none, two)" and " All patients.. were included in the intention‐to‐treat population for all analyses." |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | Unlikely to blind the anaesthesia providers to the allocated groups |
| Blinding of outcome assessors? | Low risk | "Follow‐up was undertaken by a blind observer." |
| Methods | RCT | |
| Participants | Country: Switzerland | |
| Interventions |
| |
| Outcomes | Mean propofol infusion rate (mg/kg/hr) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "...the patients were randomized into four groups by drawing lots from sealed envelopes." |
| Allocation concealment (selection bias) | Low risk | "...the patients were randomized into four groups by drawing lots from sealed envelopes." |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information regarding withdrawal or dropouts |
| Selective reporting (reporting bias) | Low risk | All expected outcome reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | "The patients, the PACU nurses and the nurses on the ward were blinded to the allocation of the patients" |
| Blinding of anaesthesiologists? | High risk | "In the BIS group, the hypnotic drug concentration... was adjusted to keep the BIS between 45 and 55 during surgery" This indicates no blinding of the anaesthesia care providers |
| Blinding of outcome assessors? | Low risk | "The patients, the PACU nurses and the nurses on the ward were blinded to the allocation of the patients." |
| Methods | RCT | |
| Participants | Country: USA N = 18836 9460, 9376 Inclusion criteria ‐Age more than 18 yr, ‐Anaesthesia using inhalational or intravenous technique ‐Surgery any surgical case that did not involve the forehead ‐Availability for follow‐up interviews Exclusion criteria ‐intracranial procedures ‐adhesive allergy ‐psychosis, or history of traumatic brain injury | |
| Interventions | 1. BIS group: electronic alerts in the event of median BIS values more than 60 2. ETAG group: electronic alerts for median age‐adjusted MAC level of less than 0.5 | |
| Outcomes | The incidence of definite intraoperative awareness (using modified intention‐to‐treat analysis) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Randomization was performed using a random‐number, computer‐generated block scheme based on even or odd operating room number" |
| Allocation concealment (selection bias) | Low risk | "...practitioners were not made aware of the randomization scheme or dates for randomization change during the study." |
| Incomplete outcome data (attrition bias) | Unclear risk | "Of the 9,460 patients randomized to the BIS intervention and successfully interviewed, 3,384 or 36% did not have BIS data recorded because of technical issues described in Materials and Methods.This population was used for secondary analysis only as a post hoc control group because it had neither intervention;" |
| Selective reporting (reporting bias) | Low risk | Selective reporting (reporting bias) |
| Blinding of patients? | Low risk | "Patients, postoperative interviewers, and all case reviewers were blinded to group assignment" |
| Blinding of anaesthesiologists? | High risk | "Practitioners receiving pages regarding BIS or MAC values were not blinded to group assignment." |
| Blinding of outcome assessors? | Low risk | "Patients, postoperative interviewers, and all case reviewers were blinded to group assignment" |
| Methods | RCT | |
| Participants | Country: Japan | |
| Interventions |
| |
| Outcomes | ‐Propofol infusion rate | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | Insufficient information |
| Blinding of patients? | Low risk | Patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | It was unlikely to blind the anaesthesia provider from the assigned groups |
| Blinding of outcome assessors? | Unclear risk | Insufficient information |
| Methods | RCT | |
| Participants | Country: Japan | |
| Interventions |
| |
| Outcomes | ‐Anaesthetic ‐ sevoflurane consumption (ml‐1) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information |
| Incomplete outcome data (attrition bias) | Unclear risk | 14 subjects were excluded: 11 subjects excluded because surgery was either longer than 6 hrs or shorter than 2 hours, and 3 patients excluded because of mechanical dysfunction of BIS.How these missing data affect on the result is unclear |
| Selective reporting (reporting bias) | Low risk | All expected outcomes were reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | Patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | It was unlikely to blind the anaesthesiologists from the assignment groups because they had to adjust the anaesthetic according to the target BIS values in the BIS group |
| Blinding of outcome assessors? | Unclear risk | Insufficient information |
| Methods | RCT | |
| Participants | Country: India Exclusion: Patients with poor ventricular function of lesser than 40%; left ventricular aneurysms; and renal/hepatic dysfunction, requiring extra corporeal circulation; preoperative or intraoperative intraaortic balloon pump, presence of unstable angina, carotid stenosis, cerebrovascular accident; excessive alcohol intake and drug abuse Isoflurane Gender: male/female 9/1, 8/2 Age: 50±6, 50±4 years Weight: 71±5, 71±6 kg Propofol Gender: male/female 8/2, 10/0 Age: 52±7, 47±5 years Weight: 71±6, 71±4 kg | |
| Interventions |
| |
| Outcomes | ‐Amount of isoflurane (ml) or propofol (ml) ‐Time to extubation ‐Intraoperative recall awareness | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information regarding the sequence generation process |
| Allocation concealment (selection bias) | Low risk | "Patients were randomly divided into four groups by a sealed envelope technique.." |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information regarding withdrawal/dropouts |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to ' learning contamination bias" during administration of the anaesthetics |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | It is unlikely to blind the anaesthesia providers who delivery the anaesthetics |
| Blinding of outcome assessors? | Unclear risk | insufficient information. The study has not stated clearly whether the intensive care unit research fellow, who was an interviewer, blinded to the group assignment or not |
| Methods | RCT, multicentre | |
| Participants | Country: Australia | |
| Interventions |
| |
| Outcomes | Primary outcome: incidence of confirmed awareness | |
| Notes | Relaxant general anaesthesia | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Computer‐generated random group allocation |
| Allocation concealment (selection bias) | Low risk | Central allocation |
| Incomplete outcome data (attrition bias) | Low risk | " ..40 patients were withdrawn because of cancellation of surgery ( BIS group13, routine group13), withdrawal of consent ( six, twoO, surgery done without general anaesthesia ( four, none), or the patients was under‐age (none, two)" and " All patients.. were included in the intention‐to‐treat population for all .analyses." |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | |
| Blinding of anaesthesiologists? | High risk | Unlikely to blind the anaesthesia providers to the allocated groups |
| Blinding of outcome assessors? | Low risk | "Follow‐up was undertaken by a blind observer." |
| Methods | RCT | |
| Participants | Country: Finland | |
| Interventions |
| |
| Outcomes | ‐Nausea and vomiting (N/V) in PACU (main outcome) (Cn, %) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | No detailed information regarding adequate sequence generation process |
| Allocation concealment (selection bias) | Unclear risk | No detailed information regarding allocation concealment |
| Incomplete outcome data (attrition bias) | Low risk | No missing outcome data Table 1 |
| Selective reporting (reporting bias) | Low risk | All expected outcomes were reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In the BIS group, sevoflurane was titrated to maintain a BIS value of 50‐60...." This indicates no blinding of the anaesthesia provider |
| Blinding of outcome assessors? | Unclear risk | The authors did not mention about the outcome assessors blinding |
| Methods | RCT | |
| Participants | Country: Italy | |
| Interventions | 1) Sevoflurane and remifentanil administration guided by BIS (Version 3.22) of 40‐60 during maintenance, Cn = 45 | |
| Outcomes | ‐Direct cost of anaesthesia management (total drug cost/min versus cost of BIS electrodes and monitor) (main outcome) | |
| Notes | Withdrawals ‐ not stated | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information regarding withdrawal or dropouts of the participants |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could probably lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In group 1 the anaesthetics were given according to the BIS value rate between 40 to 60." This indicates no blinding of the anaesthesia providers |
| Blinding of outcome assessors? | Low risk | "All recovery parameters were assessed by the same research coordinator not involved in treatment of the patient." This indicates blinding of the outcome assessors |
| Methods | RCT | |
| Participants | Country: India | |
| Interventions |
| |
| Outcomes | Number of haemodynamic disturbances: hypertension, tachycardia, hypotension, bradycardia | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "......were randomized into ......using computer‐generated numbers." This indicate adequate sequence generation |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information about the allocation concealment |
| Incomplete outcome data (attrition bias) | Low risk | From table 1 of the study, it is likely that all patients were included in the analysis |
| Selective reporting (reporting bias) | Low risk | All expected outcomes are reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In the study group, the anaesthesiologist was allowed to see and use the monitor.." This indicates no blinding of anaesthesia care providers |
| Blinding of outcome assessors? | Unclear risk | Insufficient information regarding blinding of outcome assessors |
| Methods | RCT | |
| Participants | Country: USA | |
| Interventions |
| |
| Outcomes | ‐End tidal concentrations of desflurane (%) (main outcome) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information about the sequence generation process |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information about the allocation concealment |
| Incomplete outcome data (attrition bias) | Low risk | No missing outcome data |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to ' learning information bias' |
| Blinding of patients? | Low risk | Patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | ".... , the real time AAI and BIS values were only made available during the procedure to those anaesthesiologists caring for patients in the AEP or BIS‐guided groups,..." This indicates no blinding of anaesthesia care providers |
| Blinding of outcome assessors? | Low risk | " Emergence times were determined .......by a blinded observer." This indicates blinding of outcome assessors |
| Methods | RCT | |
| Participants | Country: Saudi Arabia N =40; 20, 20 ASA: not specified Age: mean (SD) 55.3 (10.4), 60.8 (10.2) yr sex: not specified Operation: cardiac revascularization procedure by the off‐pump technique Anaesthesia: intravenous (midazolam, and sufentanil), relaxant (rocuronium), and supplemented sevoflurane Duration: of anaesthesia, mean (SD) min 239.8 (20); 230 (24.5) | |
| Interventions | 1. BIS‐guided anaesthetics for maintaining BIS values of 40‐60 2. No BIS monitoring | |
| Outcomes | 1. Anaesthetic requirements 2. The need for circulatory support (dosage of phenylephrine) 3. Extubation time 4. Intraoperative recall awareness (Cn, %) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | High risk | "Randomization was performed using patient's medical record number, being odds related to group I and evens related to group II" |
| Allocation concealment (selection bias) | High risk | "Randomization was performed using patient's medical record number, being odds related to group I and evens related to group II" |
| Incomplete outcome data (attrition bias) | Low risk | No missing data reported |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | High risk | |
| Blinding of patients? | Low risk | All patients were anaesthetised |
| Blinding of anaesthesiologists? | High risk | It was not possible to blind the anaesthesiologists |
| Blinding of outcome assessors? | Low risk | "Postoperatively, patients were visited on the second postoperative day by one of the medical staff about the grouping |
| Methods | RCT | |
| Participants | Country: USA | |
| Interventions |
| |
| Outcomes | ‐End tidal concentration (%) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | " Patients were randomly assigned to one of four study groups according to a computer‐generated random numbers table." |
| Allocation concealment (selection bias) | Unclear risk | The study has not mentioned about the allocation concealment |
| Incomplete outcome data (attrition bias) | Low risk | No missing outcome data |
| Selective reporting (reporting bias) | Low risk | All expected outcomes were reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In the BIS‐titrated groups, the volatile anaesthetics were titrated to maintain a BIS index of 60." This indicates no blinding of anaesthesia care providers |
| Blinding of outcome assessors? | Unclear risk | The study has not mentioned about outcome assessor blinding |
| Methods | RCT | |
| Participants | Country: Belgium | |
| Interventions |
| |
| Outcomes | ‐Time to spontaneous breathing | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information about the sequence generation process |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information about the allocation concealment |
| Incomplete outcome data (attrition bias) | Low risk | "No patients were excluded from analysis." |
| Selective reporting (reporting bias) | Low risk | All expected outcomes have been reported |
| Other bias | Unclear risk | Insufficient information about the blinding of the anaesthesiologists |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | It was unlikely to blind the anaesthesia providers to the assigned groups |
| Blinding of outcome assessors? | Unclear risk | Insufficient information |
| Methods | RCT | |
| Participants | Country: Italy | |
| Interventions |
| |
| Outcomes | ‐Propofol or sevoflurane consumption | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information about the sequence generation process |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information about the allocation concealment |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | Insufficient information |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | It was unlikely to blind the anaesthesia providers to the assigned groups |
| Blinding of outcome assessors? | Low risk | Accordng to Valeria Salerno translation and comments |
| Methods | RCT | |
| Participants | Country: USA | |
| Interventions |
| |
| Outcomes | ‐End tidal concentration | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information about the sequence generation process |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information about the allocation concealment |
| Incomplete outcome data (attrition bias) | Low risk | No missing outcome data |
| Selective reporting (reporting bias) | Low risk | All expected outcomes were reported |
| Other bias | Unclear risk | The unblinded anaesthesiologists could potentially lead to ' learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "....the BIS or AEP monitor, respectively, was positioned to enable the anaesthesiologist to use the displayed index value to titrate the concentration of desflurane..." This indictees no blinding of the anaesthesia care provider |
| Blinding of outcome assessors? | Low risk | ".......the times at which patients were able to open their eyes,....by a third investigator who was unaware of the monitoring group.. " This indicates blinding of outcome assessors |
| Methods | RCT | |
| Participants | Country: Canada | |
| Interventions |
| |
| Outcomes | ‐Time to orientation to person, place and time (main outcome) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | A block randomization with concealed varying block sizes was performed with computer‐generated random numbers |
| Allocation concealment (selection bias) | Unclear risk | The process of allocation concealment is unclear |
| Incomplete outcome data (attrition bias) | Low risk | "....., eight patients (three from the SP group, and five from the BIS group) were excluded from the analysis for protocol violations." The missing outcome data seem to balance across intervention group. The plausible effect size (difference in mean) among missing outcome probably not enough to have a clinically relevant impact on observed effect size |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to "learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "In the BIS group, the anaesthesiologist adjusted the administration of isoflurane and fentanyl to maintain a BIS index of 50‐60." This indicates no blinding of the anaesthesia care providers |
| Blinding of outcome assessors? | Low risk | "The Aldrete score was assessed at 15 min intervals by a research nurse blinded to the group assignment ......." |
| Methods | RCT, multicentre | |
| Participants | Country: China craniofacial and cervical surgery 774, 780 heart surgery 24, 22 gynaecologic and obstetric surgery 401, 296 chest and abdominal surgery 1217, 840 urinary surgery 213, 198 spine and limb surgery 149, 185 others 38, 37 | |
| Interventions | 1. Propofol guided by BIS (A‐2000, Aspect Medical System, USA) to maintain BIS values between 40‐60 2.Control group: no BIS‐guided TIVA | |
| Outcomes | Confirmed awareness (Cn, %) | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Despite using computer‐generated random numbers, we are uncertain regarding this type of bias because the information of group allocation was not available in 54 cases. Furthermore, there was a significant difference of ASA of greater than or equal to 3 between the two groups, 138 (5.2%) versus 65 (2.9%) |
| Allocation concealment (selection bias) | Unclear risk | Not mentioned |
| Incomplete outcome data (attrition bias) | Unclear risk | "Fifty‐four cases were withdrawn because the information of group allocation was unavailable and another 21 patients were excluded due to age younger than 18 years old ( 11/10) and a further six patients were excluded because of failure to be interviewed (2/2)." |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Blinding of patients? | Unclear risk | "Interviewers and patients were blinded to the group allocation" |
| Blinding of anaesthesiologists? | High risk | "...the doses administered were left to the discretion of the anaesthetist taking charge of the TIVA..." |
| Blinding of outcome assessors? | Low risk | "Interviewers and patients were blinded to the group allocation" |
| Methods | RCT | |
| Participants | Country: Canada | |
| Interventions |
In both groups, the sevoflurane concentration was increased in response to signs of an inadequate “depth of anaesthesia” (e.g. movement in response to surgical stimulation) | |
| Outcomes | Anaesthetic requirement: ‐sevoflurane minimal alveolar concentration (MAC) during maintenance (MAC/hr) Recovery times (min): ‐time to spontaneous eye opening ‐time to remove laryngeal mask airway (LMA) device ‐time to responding to simple verbal commands ‐time to correctly state name, age, and personal identification number ‐time to achieve fast‐track ability (main outcome) ‐time from awakening from anaesthesia to achieve post anaesthesia care unit (PACU) discharge eligibility The occurrence of any side effects The occurrence of need for therapeutic interventions The occurrence of intraoperative recall awareness Patients' satisfaction scores | |
| Notes | Muscle relaxants were not used (spontaneous breathing) | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Insufficient information |
| Allocation concealment (selection bias) | Unclear risk | Insufficient information |
| Incomplete outcome data (attrition bias) | Unclear risk | Insufficient information about withdrawals/dropouts of the participants |
| Selective reporting (reporting bias) | Low risk | All expected outcomes reported |
| Other bias | Unclear risk | The unblinded anaesthesiologist could potentially lead to 'learning contamination bias' |
| Blinding of patients? | Low risk | All patients were anaesthetized |
| Blinding of anaesthesiologists? | High risk | "The anaesthesiologists was instructed to maintain the BIS value in the 50 to 60 range by varying the inspired concentration of sevoflurane." This indicates no blinding of the anaesthesia care provider |
| Blinding of outcome assessors? | Low risk | "Early recovery endpoints were recorded....by a blinded observer,....." This indicates blinding of the assessor |
RCT = randomized controlled trial
BIS = bispectral index
TCI = target controlled infusion
Characteristics of excluded studies [ordered by study ID]
Jump to:
| Study | Reason for exclusion |
| The study was not a RCT (historical control) | |
| The study was not a RCT | |
| The study was a RCT comparing active anaesthetic monitoring (bispectral index and cerebral oxygen saturation) with a control condition on the incidence of postoperative cognitive decline in older adults undergoing surgery. The outcome (postoperative cognitive decline ) was not in the scope of this review) | |
| The study was a RCT comparing three groups (i.e. subarachnoid anaesthesia versus general anaesthesia with bispectral index versus general anaesthesia without bispectral index) but did not provide data on the relevant outcomes | |
| The study was not a RCT | |
| Outcome was not relevant (the need for postoperative analgesia) | |
| The study was not a RCT (historical control) | |
| The study was not a RCT. It was an open, observational trial with retrospective analysis | |
| This study was a RCT but compared 2 levels of BIS‐guided anaesthesia. Its publication has been withdrawn by a journal | |
| The study was a substudy of the B‐Aware randomized controlled trial (Myles 2004) and focused on dreaming during anaesthesia (PMID: 15710008) | |
| The study investigated how increasing experience from BIS in clinical practice affect the hypnotic level, drug consumption, as well as subjective opinions on this monitoring. Therefore, it did not fulfil the objective of our review | |
| Its publication has been withdrawn by a journal | |
| The study was a RCT but the randomization was different from the other studies. It allocated healthcare providers to use or not use BIS for guiding doses of anaesthetics. Therefore, the study design did not fulfil the inclusion criteria of the study selection in terms of randomization process | |
| The study was a RCT but the randomization was different from the other studies. It allocated healthcare providers to use or not use BIS for guiding doses of anaesthetics. Therefore, the study design did not fulfil the inclusion criteria of the study selection in terms of randomization process | |
| The study was not a RCT | |
| It was a multicentre RCT to evaluate the real‐time utility of BIS in predicting movement response incision. Hence, it did not fulfil the objective of this review | |
| This study was a RCT but did not use BIS guiding doses of anaesthetics but used it as a tool to measure the effect of two anaesthetics | |
| The study was a RCT but the randomization was different from the other studies. It allocated healthcare providers to use or not use BIS for guiding doses of anaesthetics. Therefore, the study design did not fulfil the inclusion criteria of the study selection in terms of randomization process | |
| This study was an RCT but was excluded as it randomly allocated participant into two groups based on the anaesthetic use (propofol versus sevoflurane). The comparison group was an historical control group |
RCT = randomized controlled trial
BIS = bispectral index
Characteristics of studies awaiting assessment [ordered by study ID]
Jump to:
| Methods | RCT |
| Participants | N=40 Operation: cholecystectomy |
| Interventions | 1. BIS‐guided sevoflurane (BIS 40‐60) 2. standard practice sevoflurane 3. BIS‐guided desflurane (BIS 40‐60) 4. standard practice desflurane |
| Outcomes | ‐ drug consumption ‐ recovery times |
| Notes | ‐ A non‐English article waiting for translation |
| Methods | RCT |
| Participants | N=480 operation: gynaecological laparoscopy surgery |
| Interventions | 1.Bispectral index‐guide anaesthesia (BIGA) 2.Non‐bispectral index‐guide anaesthesia |
| Outcomes | ‐Postoperative nausea and vomiting (PONV) ‐Desflurane consumption ‐Cost |
| Notes |
| Methods | RCT |
| Participants | N=2949 Patients at high risk of intraoperative awareness |
| Interventions | 1. BIS‐guided general anaesthesia 2. End‐tidal anaesthetic concentration‐guided general anaesthesia |
| Outcomes | ‐recovery time ‐postoperative complications such as postoperative nausea and vomiting and severe postoperative pain |
| Notes | a substudy of the B‐Unaware and BAG‐RECALL trials |
| Methods | RCT |
| Participants | N = 50 morbidly obese adult patients undergoing elective laparoscopic cholecystectomy |
| Interventions | 1. BIS guided isoflurane anaesthesia (BIS value 40‐60 during maintenance and 60‐70 at 15 minutes before the end of surgery 2. Standard clinical practice |
| Outcomes | 1. isoflurane utilization 2. early recovery profiles |
| Notes |
| Methods | RCT |
| Participants | N=80 severe burn undergoing elective escharectomy |
| Interventions | 1.BIS guided intravenous target‐controlled infusion (TCI) of remifentanil and propofol. 2. Control: non‐BIS guided anaesthesia |
| Outcomes | ‐target concentrations of remifentanil and propofol ‐time from drug withdrawal to eye opening |
| Notes |
| Methods | RCT |
| Participants | N=60 Halothane based anaesthesia |
| Interventions | 1.BIS‐guided anaesthesia 2.ETAG‐guided anaesthesia |
| Outcomes | ‐time to tracheal extubation |
| Notes |
| Methods | RCT |
| Participants | Open heart surgery |
| Interventions | 1.BIS‐guided anaesthesia 2. No BIS |
| Outcomes | Consumption of anaesthetics Intraoperative recall awareness |
| Notes | Full text: not available |
| Methods | RCT |
| Participants | N=82 Adults (20‐60 years) Supratentorial neurosurgery |
| Interventions | 1. BIS guided anaesthesia (BIS values 40‐60) 2. Standard control group; Clinical signs (haemodynamics) guided anaesthesia |
| Outcomes | ‐Drugs including anaesthetics used during anaesthesia ‐Haemodynamic changes ‐Recovery time |
| Notes |
| Methods | RCT |
| Participants | N=96 Open renal surgery |
| Interventions | 1. BIS group 2.Control group (clinical assessment) |
| Outcomes | ‐Depth of anaesthesia ‐Recovery time |
| Notes |
| Methods | RCT |
| Participants | N=42 Desflurane anaesthesia balanced with remifentanil |
| Interventions | 1. BIS guided anaesthesia (BIS at 50 during maintenance) 2. Fixed gas concentration method (1 MAC desflurane) |
| Outcomes | ‐Dose and adjustment frequency of anaesthetics ‐Recovery time ‐Cost |
| Notes |
| Methods | RCT |
| Participants | N= not mentioned Coronary artery bypass surgery without cardiopulmonary bypass (CPB) |
| Interventions | 1. BIS visible 2. BIS not visible ((BIS is hidden and monitoring of anaesthetic depth is based on clinical signs associated with the monitoring of expiratory fraction of halogenated anaesthetic agent) |
| Outcomes | ‐Anaesthetic depth ‐Associate costs |
| Notes | a research protocol |
| Methods | RCT |
| Participants | N=333 Elective abdominal surgery |
| Interventions | 1. BIS monitoring 2. Routine monitoring |
| Outcomes | ‐ Awareness ‐Changes in haemodynamic parameter |
| Notes |
| Methods | A prospective, controlled, sequential two‐arm clinical study |
| Participants | N=60 elective on‐pump cardiac surgery |
| Interventions | 1. BIS guided sevoflurane anaesthesia (BIS target between 40 and 60) 2. a sustained inspired concentration of sevoflurane 1.8% |
| Outcomes | ‐sevoflurane plasma concentration (SPC) ‐intraoperative vasopressor doses during on‐pump ‐intraoperative awareness, postoperative blood lactate concentration, duration of mechanical ventilation, intensive care unit length of stay and kidney injury |
| Notes |
| Methods | RCT |
| Participants | Country: China N=300 Anaesthesia: total intravenous anaesthesia |
| Interventions | 1. BIS‐guided anaesthesia 2. No BIS |
| Outcomes | Intraoperative recall awareness |
| Notes | Full text: not available |
| Methods | RCT |
| Participants | N=90 Endobronchial ultrasound (EBUS) under sedation1 |
| Interventions | 1.BIS guided sedation 2 .modified observer's assessment of alertness/sedation scale clinical evaluation |
| Outcomes | ‐Drug doses ‐Waking time ‐Adverse events, and tolerance of the procedure |
| Notes |
| Methods | RCT |
| Participants | N = 294 Cardiac surgery |
| Interventions | 1.BIS guided anaesthesia 2.MAC guided anaesthesia |
| Outcomes | ‐Time to extubation ‐Length of stay in the ICU and total postoperative hospital length of stay. |
| Notes |
| Methods | RCT |
| Participants | N=723 Patients undergoing cardiac surgery. |
| Interventions | 1. BIS guided anaesthesia (target BIS 40‐60) 2. End‐tidal anaesthetic concentration (ETAC) guided anaesthesia |
| Outcomes | ‐Time to tracheal extubation. |
| Notes | A single institution who were enrolled in the larger, multicentre BIS or Anaesthesia Gas to Reduce Explicit Recall (BAG‐RECALL) clinical trial. |
Acronyms and abbreviations used in these tables
BAG‐RECALL: a multi‐centre, randomized, controlled clinical trial comparing bispectral index (BIS) guided versus end‐tidal anaesthetic concentration (ETAC) guided anaesthesia on explicit recall in patients at high risk of intraoperative recall awareness; BIGA: Bispectral index‐guide anaesthesia; BIS: Bispectral index; EBUS: Endobronchial ultrasound; :ETAC: End‐tidal anaesthetic concentration; ICU: Intensive care unit..
Data and analyses
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Risk of awareness in BIS versus CS guided anaesthesia Show forest plot | 4 | 7761 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 0.24 [0.12, 0.48] |
| Analysis 1.1  Comparison 1 Bispectral index versus standard practice (risk of awareness in surgical patients with high risk of awareness), Outcome 1 Risk of awareness in BIS versus CS guided anaesthesia. | ||||
| 2 Risk of awareness in BIS versus ETAG guided anaesthesia Show forest plot | 4 | 26530 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 1.13 [0.56, 2.26] |
| Analysis 1.2  Comparison 1 Bispectral index versus standard practice (risk of awareness in surgical patients with high risk of awareness), Outcome 2 Risk of awareness in BIS versus ETAG guided anaesthesia. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Time to eyes opening (minutes) Show forest plot | 20 | 2557 | Mean Difference (IV, Random, 95% CI) | ‐1.93 [‐2.70, ‐1.16] |
| Analysis 2.1  Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 1 Time to eyes opening (minutes). | ||||
| 1.1 propofol | 7 | 552 | Mean Difference (IV, Random, 95% CI) | ‐3.59 [‐5.15, ‐2.04] |
| 1.2 desflurane | 4 | 322 | Mean Difference (IV, Random, 95% CI) | ‐0.51 [‐1.44, 0.42] |
| 1.3 isoflurane | 1 | 60 | Mean Difference (IV, Random, 95% CI) | ‐0.90 [‐2.32, 0.52] |
| 1.4 sevoflurane | 8 | 530 | Mean Difference (IV, Random, 95% CI) | ‐1.42 [‐2.45, ‐0.38] |
| 1.5 propofol/volatile anaesthetics | 1 | 1093 | Mean Difference (IV, Random, 95% CI) | ‐1.73 [‐1.00, ‐0.46] |
| 2 Time to respond to verbal command (minutes) Show forest plot | 12 | 777 | Mean Difference (IV, Random, 95% CI) | ‐2.73 [‐3.92, ‐1.54] |
| Analysis 2.2  Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 2 Time to respond to verbal command (minutes). | ||||
| 2.1 propofol | 3 | 359 | Mean Difference (IV, Random, 95% CI) | ‐4.88 [‐7.57, ‐2.20] |
| 2.2 desflurane | 3 | 130 | Mean Difference (IV, Random, 95% CI) | ‐3.38 [‐4.68, ‐2.07] |
| 2.3 isoflurane | 2 | 90 | Mean Difference (IV, Random, 95% CI) | ‐3.86 [‐11.87, 4.15] |
| 2.4 sevoflurane | 4 | 198 | Mean Difference (IV, Random, 95% CI) | ‐1.30 [‐3.06, 0.46] |
| 3 Time to extubation (minutes) Show forest plot | 18 | 1501 | Mean Difference (IV, Random, 95% CI) | ‐2.62 [‐3.46, ‐1.78] |
| Analysis 2.3  Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 3 Time to extubation (minutes). | ||||
| 3.1 propofol | 6 | 539 | Mean Difference (IV, Random, 95% CI) | ‐4.55 [‐5.36, ‐3.73] |
| 3.2 desflurane | 6 | 432 | Mean Difference (IV, Random, 95% CI) | ‐1.64 [‐2.97, ‐0.32] |
| 3.3 isoflurane | 0 | 0 | Mean Difference (IV, Random, 95% CI) | 0.0 [0.0, 0.0] |
| 3.4 sevoflurane | 9 | 530 | Mean Difference (IV, Random, 95% CI) | ‐2.29 [‐3.24, ‐1.35] |
| 4 Time to orientation (minutes) Show forest plot | 7 | 373 | Mean Difference (IV, Fixed, 95% CI) | ‐3.06 [‐3.63, ‐2.50] |
| Analysis 2.4  Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 4 Time to orientation (minutes). | ||||
| 4.1 propofol | 1 | 20 | Mean Difference (IV, Fixed, 95% CI) | ‐2.19 [‐8.19, 3.81] |
| 4.2 desflurane | 2 | 70 | Mean Difference (IV, Fixed, 95% CI) | ‐2.60 [‐4.23, ‐0.97] |
| 4.3 isoflurane | 1 | 44 | Mean Difference (IV, Fixed, 95% CI) | ‐3.6 [‐5.92, ‐1.28] |
| 4.4 sevoflurane | 4 | 239 | Mean Difference (IV, Fixed, 95% CI) | ‐3.10 [‐3.73, ‐2.48] |
| 5 PACU stay (minutes) Show forest plot | 12 | 1953 | Mean Difference (IV, Random, 95% CI) | ‐6.75 [‐11.20, ‐2.31] |
| Analysis 2.5  Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 5 PACU stay (minutes). | ||||
| 5.1 propofol | 3 | 318 | Mean Difference (IV, Random, 95% CI) | ‐5.84 [‐10.07, ‐1.62] |
| 5.2 desflurane | 4 | 272 | Mean Difference (IV, Random, 95% CI) | ‐14.76 [‐29.61, 0.09] |
| 5.3 isoflurane | 1 | 60 | Mean Difference (IV, Random, 95% CI) | ‐14.00 [‐34.12, 6.12] |
| 5.4 sevoflurane | 4 | 180 | Mean Difference (IV, Random, 95% CI) | ‐7.56 [‐15.85, 0.72] |
| 5.5 propofol/volatile anaesthetics | 1 | 1123 | Mean Difference (IV, Random, 95% CI) | ‐3.41 [‐9.72, 2.90] |
| 6 Time to home readiness (minutes) Show forest plot | 6 | 329 | Mean Difference (IV, Random, 95% CI) | ‐7.01 [‐30.11, 16.09] |
| Analysis 2.6  Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 6 Time to home readiness (minutes). | ||||
| 6.1 propofol | 1 | 39 | Mean Difference (IV, Random, 95% CI) | ‐5.36 [‐33.01, 22.29] |
| 6.2 isoflurane | 0 | 0 | Mean Difference (IV, Random, 95% CI) | 0.0 [0.0, 0.0] |
| 6.3 desflurane | 2 | 70 | Mean Difference (IV, Random, 95% CI) | ‐30.93 [‐107.35, 45.48] |
| 6.4 sevoflurane | 4 | 220 | Mean Difference (IV, Random, 95% CI) | 8.93 [‐4.49, 22.35] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Normalized propofol infusion rate (mg/kg/hr) Show forest plot | 10 | 672 | Mean Difference (IV, Random, 95% CI) | ‐1.32 [‐1.91, ‐0.73] |
| Analysis 3.1  Comparison 3 Bispectral index versus clinical signs (requirement for anaesthetics), Outcome 1 Normalized propofol infusion rate (mg/kg/hr). | ||||
| 2 Volatile anaesthetic requirement, minimal alveolar concentration equivalents (MAC equivalents) Show forest plot | 14 | 985 | Std. Mean Difference (IV, Random, 95% CI) | ‐0.65 [‐1.01, ‐0.28] |
| Analysis 3.2  Comparison 3 Bispectral index versus clinical signs (requirement for anaesthetics), Outcome 2 Volatile anaesthetic requirement, minimal alveolar concentration equivalents (MAC equivalents). | ||||
| 2.1 desflurane | 5 | 352 | Std. Mean Difference (IV, Random, 95% CI) | ‐1.02 [‐2.03, ‐0.01] |
| 2.2 isoflurane | 1 | 60 | Std. Mean Difference (IV, Random, 95% CI) | ‐0.37 [‐0.88, 0.14] |
| 2.3 sevoflurane | 9 | 573 | Std. Mean Difference (IV, Random, 95% CI) | ‐0.52 [‐0.87, ‐0.18] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Total dose of fentanyl (microgramme) Show forest plot | 7 | 333 | Mean Difference (IV, Random, 95% CI) | 13.80 [‐19.80, 47.40] |
| Analysis 4.1  Comparison 4 Bispectral index versus clinical signs (requirement for narcotics), Outcome 1 Total dose of fentanyl (microgramme). | ||||
| 2 average normalized remifentanil infusion rates ( microgramme/kg/min) Show forest plot | 3 | 276 | Mean Difference (IV, Fixed, 95% CI) | ‐0.01 [‐0.02, ‐0.00] |
| Analysis 4.2  Comparison 4 Bispectral index versus clinical signs (requirement for narcotics), Outcome 2 average normalized remifentanil infusion rates ( microgramme/kg/min). | ||||
| 3 Total dose of sufentanil ( microgramme) Show forest plot | 1 | 40 | Mean Difference (IV, Fixed, 95% CI) | ‐33.80 [‐51.03, ‐16.57] |
| Analysis 4.3  Comparison 4 Bispectral index versus clinical signs (requirement for narcotics), Outcome 3 Total dose of sufentanil ( microgramme). | ||||
Methodological quality graph: review authors' judgements about each methodological quality item presented as percentages across all included studies.
Methodological quality summary: review authors' judgements about each methodological quality item for each included study.
Funnel plot of comparison: bispectral index versus clinical signs on the requirement of propofol infusion rate (mg/kg/hr).
Funnel plot of comparison: bispectral index versus clinical signs on requirement of volatile anaesthetic (minimal alveolar concentration equivalents, MAC equivalents).
Comparison 1 Bispectral index versus standard practice (risk of awareness in surgical patients with high risk of awareness), Outcome 1 Risk of awareness in BIS versus CS guided anaesthesia.
Comparison 1 Bispectral index versus standard practice (risk of awareness in surgical patients with high risk of awareness), Outcome 2 Risk of awareness in BIS versus ETAG guided anaesthesia.
Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 1 Time to eyes opening (minutes).
Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 2 Time to respond to verbal command (minutes).
Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 3 Time to extubation (minutes).
Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 4 Time to orientation (minutes).
Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 5 PACU stay (minutes).
Comparison 2 Bispectral index versus clinical signs (recovery profiles), Outcome 6 Time to home readiness (minutes).
Comparison 3 Bispectral index versus clinical signs (requirement for anaesthetics), Outcome 1 Normalized propofol infusion rate (mg/kg/hr).
Comparison 3 Bispectral index versus clinical signs (requirement for anaesthetics), Outcome 2 Volatile anaesthetic requirement, minimal alveolar concentration equivalents (MAC equivalents).
Comparison 4 Bispectral index versus clinical signs (requirement for narcotics), Outcome 1 Total dose of fentanyl (microgramme).
Comparison 4 Bispectral index versus clinical signs (requirement for narcotics), Outcome 2 average normalized remifentanil infusion rates ( microgramme/kg/min).
Comparison 4 Bispectral index versus clinical signs (requirement for narcotics), Outcome 3 Total dose of sufentanil ( microgramme).
| Bispectral index versus standard practice (risk of awareness in surgical patients with high risk of awareness) for improving anaesthetic delivery and postoperative recovery | ||||||
| Patient or population: patients for improving anaesthetic delivery and postoperative recovery | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Control | Bispectral index versus standard practice (risk of awareness in surgical patients with high risk of awareness) | |||||
| Awareness in surgical patients with high risk of recall awareness ‐ using clinical signs as the guide in standard practice | Study population | OR 0.24 | 7761 | ⊕⊕⊕⊝ | ||
| 8 per 1000 | 2 per 1000 | |||||
| Moderate | ||||||
| 8 per 1000 | 2 per 1000 | |||||
| Awareness in surgical patients with high risk of recall awareness ‐ using end tidal anaesthetic gas as the guide | Study population | OR 1.13 | 26530 | ⊕⊕⊝⊝ | ||
| 1 per 1000 | 1 per 1000 | |||||
| Moderate | ||||||
| 1 per 1000 | 1 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 clinical heterogeneity | ||||||
| Study | Anaesthetic technique | Titrating strategies |
| Endotracheal GA. Induction: sevoflurane | Sevoflurane/sufentanil titrated for increased blood pressure/heart rate > 20%, despite a BIS value of 50‐60 or end tidal sevoflurane concentration 2% | |
| Endotracheal GA, Induction: propofol‐sufentanil Intubation: atracurium Maintenance: sevoflurane and nitrous oxide in oxygen, sufentanil, atracurium | BIS group: intermittent bolus dose of sufentanil despite BIS or Entropy values within the recommended range Control group (CS group): increased sevoflurane concentration or intermittent bolus doses of intravenous sufentanil for signs of inadequate anaesthesia, i.e. hypertension and bradycardia | |
| LMA GA. Induction: propofol‐alfentanil | NA | |
| LMA GA. Induction: propofol‐fentanyl | NA | |
| Endotracheal GA. Induction: fentanyl‐thiopentone | Inadequate analgesia in both groups managed by increased concentration of sevoflurane (no supplemental fentanyl) | |
| Endotracheal GA. Induction: fentanyl‐thiopentone | BIS group: additional fentanyl was administered in 0.1mg doses when the BIS value rose to 55. With inadequate decreases in the haemodynamic values, sevoflurane concentration was increased by 20% | |
| Endotracheal GA. Induction: remifentanil‐propofol | BIS group: desflurane during maintenance was continuously adjusted according to a target value of ‘50’. In case anaesthesia was judged inadequate despite the BIS target value, the infusion rate of remifentanil could be increased. | |
| Endotracheal GA. Induction: fentanyl‐propofol | BIS group: adjustment of the propofol infusion to achieve BIS 40 to 50 | |
| Endotracheal GA plus regional anaesthesia for intraoperative and postoperative pain control Induction: remifentanil, propofol Intubation:cis‐atracurium Maintenance: propofol infusion, remifentanil infusion | During maintenance of anaesthesia, all patients were assessed for signs of inadequate anaesthesia, hypotension or bradycardia. Inadequate anaesthesia was defined as hypertension, tachycardia or patient movement, eye‐opening, swallowing, grimacing, lacrimation or sweating. The definition of adverse haemodynamic responses was adapted from Garrioch et al15: responses were classified as ‘hypertension’ (SAP >40 mmHg from baseline), ‘hypotension’ (SAP <40 mmHg from baseline), ‘tachycardia’ (HR >100 beats/minute‐1) and ‘bradycardia’ (HR <45 beats/minute‐1). In the standard practice group, if anaesthesia was judged inadequate the propofol concentration was increased in steps of 1 mg/kg/hour as necessary | |
| Endotracheal/LMA anaesthesia | BIS group: increasing alfentanil if BIS was within the recommended range (45‐60) | |
| Endotracheal GA. Induction: propofol Maintenance: propofol‐fentanyl‐mivacurium | Signs of inadequate anaesthesia managed in both groups by fentanyl | |
| Endotracheal GA. Induction: fentanyl‐propofol Intubation: succinylcholine. Maintenance: sevoflurane, nitrous oxide in oxygen, fentanyl, and atracurium | Any instances of inadequate anaesthesia were managed by increasing the concentration of sevoflurane | |
| Endotracheal GA. Induction : propofol, Intubation:atracurium Maintenance: sevoflurane, 50% nitrous oxide in oxygen, atracurium by TOF, fentanyl | BIS group:If the patient in that group, exhibited hypertension or tachycardia the mode of treatment was dependent on the BIS index. If the BIS index was >60, anaesthesia was deepened by increasing sevoflurane concentration until BIS index was between 50 and 60. If BIS index was already in the targeted range and the patient exhibited hypertension or tachycardia, fentanyl 25‐50 μg IV was given. If BIS index was <50, sevoflurane was decreased and patient was checked for signs of lack of analgesia (i.e., lacrimation, grimacing, movement). In case of lack of analgesia, fentanyl 25‐50 μg IV was administered. But if no signs of lack of analgesia, labetalol 5‐10 mg IV was administered Standard practice group: If the patient in this group exhibited hypertension (mean arterial blood pressure >25% above baseline) (MBP) and tachycardia (heart rate (HR) >90 beats min‐1), anaesthesia was deepened either by increasing inspired sevoflurane concentration, or administering fentanyl 25‐50 μg or labetalol 5‐10 mg IV. The mode of treatment was left to anaesthesiologist’s discretion | |
| Endotracheal GA. Induction: propofol‐remifentanil | Remifentanil infusion was given in both groups for signs of inadequate anaesthesia despite achieving propofol target concentration or a target value of 50 for BIS | |
| Endotracheal GA, Induction: propofol‐remifentanil | BIS group: desflurane during maintenance was continuously adjusted according to a target value of ‘50’. In case anaesthesia was judged inadequate despite the BIS target value, the infusion rate of remifentanil could be increased. | |
| Relaxant general anaesthesia. Induction: midazolam‐propofol or thiopentone Intubation: nondepolarizing muscle relaxants. Maintenance: propofol or volatiles‐nitrous oxide‐opioids. Hypnotic drugs. Combined general and regional anaesthesia | Narcotic analgesics on the discretion of the attending anaesthesiologists | |
| Endotracheal GA | BIS group: propofol or desflurane to keep BIS 45‐55 and opioids according clinical criteria | |
| Endotracheal GA | NA | |
| Endotracheal GA | Managed by fentanyl 50‐100 µg, despite 2% in sevoflurane in both groups | |
| Relaxant general anaesthesia. Induction: midazolam‐propofol or thiopentone Intubation: nondepolarizing muscle relaxants. Maintenance: Propofol or volatiles‐nitrous oxide‐opioids. Hypnotic drugs. Combined general and regional anaesthesia | Narcotic analgesics on the discretion of the attending anaesthesiologists | |
| Endotracheal GA. Induction:propofol Intubation: rocuronium | Supplemental alfentanil given for haemodynamic variables >25% of the preanaesthetic value, despite BIS of 50‐60 in BIS group or sevoflurane concentration of 1.4% in CP group | |
| Endotracheal GA. Induction: remifentanil ‐ thiopentone Intubation: vecuronium Maintenance: sevoflurane‐nitrous oxide‐remifentanil‐vecuronium | Remifentanil infusion (0.4 µG/kg/min) for both groups | |
| Endotracheal GA. Induction: midazolam‐morphine‐thiopentone | Signs of inadequate analgesia (tachycardia, hypertension, sweating, lacrimation etc) in both groups managed by morphine before vasodilators or beta‐blocker | |
| Endotracheal GA Premedication: Induction: propofol‐fentanyl | Intermittent intravenous fentanyl 0.5 mg/kg as needed to maintain haemodynamic variables within 15% of the baseline value | |
| Endotracheal GA. Induction: fentanyl‐propofol. Intubation:succinylcholine Maintenance: desflurane or sevoflurane‐nitrous‐fentanyl‐mivacurium (at least 1‐2 TOF) | Inadequate analgesia (haemodynamic variables >20%of baseline) managed by supplemental doses of fentanyl (25‐30 µg) | |
| Endotracheal GA. Induction: remifentanil, propofol .Intubation: rocuronium. Maintenance: remifentanil infusion (0.5 µg/kg/min)‐propofol infusion | Remifentanil infusion | |
| Endotracheal GA. Induction: Propofol. Intubation: Cis‐atracurium. Maintenance: propofol infusion or sevoflurane‐nitrous oxide‐cisatracurium‐fentanyl | NA | |
| Endotracheal GA. Induction: propofol and fentanyl Intubation: succinylcholine. Maintenance: desflurane‐nitrous‐cisatracurium | Esmolol to treat sustained increased heart rate | |
| Endotracheal GA. Induction: propofol‐fentanyl‐midazolam | BIS group: BIS > 60 increasing isoflurane concentration; BIS = 50‐60 giving supplemental fentanyl; BIS < 50 decreasing isoflurane concentration and supplementing fentanyl (signs of inadequate anaesthesia) or labetalol (no sign of inadequate anaesthesia) | |
| LMA GA. Induction: propofol‐fentanyl | In both groups, the sevoflurane concentration was increased in response to signs of an inadequate “depth of anaesthesia” (e.g. movement in response to surgical stimulation) | |
| GA = general anaesthesia, LMA = laryngeal mask airway, TCI = target controlled infusion NA = not available | ||
| Trial | Outcome | Value | BIS group | CS group | Note |
| Bispectral index (BIS) during operation | Mean | Not applicable | Not applicable | Data not available | |
| BIS during operation | Mean | Cn = 30; mean = 44.9; SD (standard deviation) = 5.15 | Cn = 30; mean = 40.5; SD = 4.53 | ||
| BIS index during maintenance | Mean | Cn = 24; mean = 54 ; SD = 4 | Cn = 23; mean = 46; SD = 5 | ||
| BIS index during maintenance | Mean | Data presented as a graph showing comparable BIS values between BIS and control (CS) groups at various point of anaesthesia | |||
| BIS index during cardiopulmonary by pass | Mean | ||||
| Intraoperative BIS | Mean | mean = 44.35 SD = 5.25 | mean = 45.89 SD = 5.98 | ||
| BIS index during maintenance | Mean | Not applicable | Not applicable | Data presented as a graph showing BIS values at various points of anaesthesia in BIS group > in SP group | |
| BIS index during maintenance | Median | Cn = 20; mean = 46.4; 95% confidence interval (CI ) = 44.4 to 44.8 | Cn = 20; mean = 42.2; 95% CI = 40.1 to 44.2 | Data presented as a graph showing BIS values at various points during cardiopulmonary bypass in BIS group > in SP group | |
| BIS index during maintenance | Mean | Not applicable | Not applicable | Data: not available | |
| BIS index during maintenance After discontinuation of anaesthesia | Mean | mean = 52.4 , SD = 3.4 mean = 70.1 SD = 11.2 | Mean = 41.2 SD = 7.3 mean = 66.5 SD = 14.3 | None of patients reported awareness | |
| BIS index during maintenance | Mean | Not applicable | Not applicable | Data presented as a graph showing BIS values at various points of anaesthesia in BIS group >in SP group | |
| BIS index during maintenance and at the end of surgery | Mean | Data presented as a graph showing comparable BIS values between BIS and control (CS) groups at various point during operation. At the end of surgery, BIS values were significantly higher in the BIS group | |||
| BIS index during skin incision | Mean | Cn = 20; mean = 46; SD = 6 | Cn = 19; mean = 47; SD = 10 | ||
| BIS 10 minutes before end of surgery | Mean | Cn = 20; mean = 59; SD = 6 | Cn =19; mean = 52; SD = 9 | ||
| BIS at end of surgery | Mean | Cn = 20; mean = 69; SD = 12 | Cn = 19; mean = 60; SD = 9 | ||
| BIS at end of anaesthesia | Mean | Cn = 20; mean = 92; SD = 6 | Cn = 19; mean = 88; SD = 6 | ||
| BIS index during maintenance | Mean | Not applicable | Not applicable | Data presented as graph showed BIS values at various points of anaesthesia in BIS group < in SP group | |
| BIS during surgery | Median | Cn = 32; median = 54; min‐max = 49‐61 | Cn = 30; median = 55; min‐max = 30‐65 | ||
| BIS during surgery | Median | Cn = 45; median = 46; min‐max = 36‐67 | Cn = 45; median = 42; min‐max = 39‐61 | ||
| BIS after skin closure | Median | Cn = 45; median = 62; min‐max = 43‐98 | Cn = 45; median = 54; min‐max = 34‐99 | ||
| BIS index during maintenance | Mean | Cn = 30; mean = 49; SD = 13 | Cn = 30; mean = 40; SD = 11 | ||
| BIS during emergence from anaesthesia | Mean | Cn = 30; mean = 88; SD =11 | Cn = 30; mean = 88; SD = 12 | At the time of eye opening before removal of endotracheal tube | |
| BIS index during operation | Mean | Cn = 15; mean = 60; SD = 4 | Cn = 15; mean = 44; SD = 11 | ||
| BIS during operation | Mean | Cn = 15; mean = 62; SD =3 | Cn = 15; mean = 42; SD = 8 | ||
| BIS index during maintenance | Mean | Cn = 20; mean = 57; SD = 12 | Cn = 20; mean = 41; SD = 10 | ||
| BIS index during operation | Mean | Cn = 29; mean = 51; SD = 4.9 | Cn = 31; mean = 44.3; SD = 8.8 | ||
| BIS index at discontinuation of anaesthesia | Mean | Cn = 29; mean = 68; SD =13 | Cn = 31; mean = 64; SD = 13 | ||
| BIS index during operation | Mean | Cn = 25, mean= 57; SD = 10 | Cn = 25, mean = 59; SD =10 | ||
| BIS index upon discontinuation of sevoflurane | Mean | Cn = 25, mean= 57; SD = 17 | Cn = 25, mean = 58; SD = 18 | ||
| BIS index upon removal of airway device | Mean | Cn = 25, mean = 78; SD = 13 | Cn = 25, mean = 81; SD = 14 |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Risk of awareness in BIS versus CS guided anaesthesia Show forest plot | 4 | 7761 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 0.24 [0.12, 0.48] |
| 2 Risk of awareness in BIS versus ETAG guided anaesthesia Show forest plot | 4 | 26530 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 1.13 [0.56, 2.26] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Time to eyes opening (minutes) Show forest plot | 20 | 2557 | Mean Difference (IV, Random, 95% CI) | ‐1.93 [‐2.70, ‐1.16] |
| 1.1 propofol | 7 | 552 | Mean Difference (IV, Random, 95% CI) | ‐3.59 [‐5.15, ‐2.04] |
| 1.2 desflurane | 4 | 322 | Mean Difference (IV, Random, 95% CI) | ‐0.51 [‐1.44, 0.42] |
| 1.3 isoflurane | 1 | 60 | Mean Difference (IV, Random, 95% CI) | ‐0.90 [‐2.32, 0.52] |
| 1.4 sevoflurane | 8 | 530 | Mean Difference (IV, Random, 95% CI) | ‐1.42 [‐2.45, ‐0.38] |
| 1.5 propofol/volatile anaesthetics | 1 | 1093 | Mean Difference (IV, Random, 95% CI) | ‐1.73 [‐1.00, ‐0.46] |
| 2 Time to respond to verbal command (minutes) Show forest plot | 12 | 777 | Mean Difference (IV, Random, 95% CI) | ‐2.73 [‐3.92, ‐1.54] |
| 2.1 propofol | 3 | 359 | Mean Difference (IV, Random, 95% CI) | ‐4.88 [‐7.57, ‐2.20] |
| 2.2 desflurane | 3 | 130 | Mean Difference (IV, Random, 95% CI) | ‐3.38 [‐4.68, ‐2.07] |
| 2.3 isoflurane | 2 | 90 | Mean Difference (IV, Random, 95% CI) | ‐3.86 [‐11.87, 4.15] |
| 2.4 sevoflurane | 4 | 198 | Mean Difference (IV, Random, 95% CI) | ‐1.30 [‐3.06, 0.46] |
| 3 Time to extubation (minutes) Show forest plot | 18 | 1501 | Mean Difference (IV, Random, 95% CI) | ‐2.62 [‐3.46, ‐1.78] |
| 3.1 propofol | 6 | 539 | Mean Difference (IV, Random, 95% CI) | ‐4.55 [‐5.36, ‐3.73] |
| 3.2 desflurane | 6 | 432 | Mean Difference (IV, Random, 95% CI) | ‐1.64 [‐2.97, ‐0.32] |
| 3.3 isoflurane | 0 | 0 | Mean Difference (IV, Random, 95% CI) | 0.0 [0.0, 0.0] |
| 3.4 sevoflurane | 9 | 530 | Mean Difference (IV, Random, 95% CI) | ‐2.29 [‐3.24, ‐1.35] |
| 4 Time to orientation (minutes) Show forest plot | 7 | 373 | Mean Difference (IV, Fixed, 95% CI) | ‐3.06 [‐3.63, ‐2.50] |
| 4.1 propofol | 1 | 20 | Mean Difference (IV, Fixed, 95% CI) | ‐2.19 [‐8.19, 3.81] |
| 4.2 desflurane | 2 | 70 | Mean Difference (IV, Fixed, 95% CI) | ‐2.60 [‐4.23, ‐0.97] |
| 4.3 isoflurane | 1 | 44 | Mean Difference (IV, Fixed, 95% CI) | ‐3.6 [‐5.92, ‐1.28] |
| 4.4 sevoflurane | 4 | 239 | Mean Difference (IV, Fixed, 95% CI) | ‐3.10 [‐3.73, ‐2.48] |
| 5 PACU stay (minutes) Show forest plot | 12 | 1953 | Mean Difference (IV, Random, 95% CI) | ‐6.75 [‐11.20, ‐2.31] |
| 5.1 propofol | 3 | 318 | Mean Difference (IV, Random, 95% CI) | ‐5.84 [‐10.07, ‐1.62] |
| 5.2 desflurane | 4 | 272 | Mean Difference (IV, Random, 95% CI) | ‐14.76 [‐29.61, 0.09] |
| 5.3 isoflurane | 1 | 60 | Mean Difference (IV, Random, 95% CI) | ‐14.00 [‐34.12, 6.12] |
| 5.4 sevoflurane | 4 | 180 | Mean Difference (IV, Random, 95% CI) | ‐7.56 [‐15.85, 0.72] |
| 5.5 propofol/volatile anaesthetics | 1 | 1123 | Mean Difference (IV, Random, 95% CI) | ‐3.41 [‐9.72, 2.90] |
| 6 Time to home readiness (minutes) Show forest plot | 6 | 329 | Mean Difference (IV, Random, 95% CI) | ‐7.01 [‐30.11, 16.09] |
| 6.1 propofol | 1 | 39 | Mean Difference (IV, Random, 95% CI) | ‐5.36 [‐33.01, 22.29] |
| 6.2 isoflurane | 0 | 0 | Mean Difference (IV, Random, 95% CI) | 0.0 [0.0, 0.0] |
| 6.3 desflurane | 2 | 70 | Mean Difference (IV, Random, 95% CI) | ‐30.93 [‐107.35, 45.48] |
| 6.4 sevoflurane | 4 | 220 | Mean Difference (IV, Random, 95% CI) | 8.93 [‐4.49, 22.35] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Normalized propofol infusion rate (mg/kg/hr) Show forest plot | 10 | 672 | Mean Difference (IV, Random, 95% CI) | ‐1.32 [‐1.91, ‐0.73] |
| 2 Volatile anaesthetic requirement, minimal alveolar concentration equivalents (MAC equivalents) Show forest plot | 14 | 985 | Std. Mean Difference (IV, Random, 95% CI) | ‐0.65 [‐1.01, ‐0.28] |
| 2.1 desflurane | 5 | 352 | Std. Mean Difference (IV, Random, 95% CI) | ‐1.02 [‐2.03, ‐0.01] |
| 2.2 isoflurane | 1 | 60 | Std. Mean Difference (IV, Random, 95% CI) | ‐0.37 [‐0.88, 0.14] |
| 2.3 sevoflurane | 9 | 573 | Std. Mean Difference (IV, Random, 95% CI) | ‐0.52 [‐0.87, ‐0.18] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Total dose of fentanyl (microgramme) Show forest plot | 7 | 333 | Mean Difference (IV, Random, 95% CI) | 13.80 [‐19.80, 47.40] |
| 2 average normalized remifentanil infusion rates ( microgramme/kg/min) Show forest plot | 3 | 276 | Mean Difference (IV, Fixed, 95% CI) | ‐0.01 [‐0.02, ‐0.00] |
| 3 Total dose of sufentanil ( microgramme) Show forest plot | 1 | 40 | Mean Difference (IV, Fixed, 95% CI) | ‐33.80 [‐51.03, ‐16.57] |
