Clinical Management of Latex-Allergic Children

Latex allergy in children with myelodysplasia and congenital urological anomalies has been well recognized in recent years ^[1-9]. Yet there is a paucity of outcome data after latex avoidance during perioperative care. Furthermore, it remains unclear whether premedication regimens for attenuating the allergic response are beneficial ^[8,10-13]. This report describes the patients' histories and allergy evaluations, and our clinical results recorded as a concurrent audit, and confirms our initial favorable experience with the avoidance of chemoprophylaxis in a latex-safe environment ^[7,14].

Methods

One hundred sixty-two children with latex allergy established by clinical history, allergy testing, or both (Table 1) presented to our operating room for 267 surgical procedures (Table 2) over a 6-yr period. The 162 patients were 11.6 +/- 5.8 yr old (range 1-31 yr). Primary diagnoses were myelodysplasia in 139 patients, extrophy of the bladder in 10 patients, and cloacal extrophy in 11 patients; 1 patient had undergone a tracheoesophageal fistula repair in infancy requiring repeat bougienage with red rubber bougies, and 1 patient was allergic to latex for reasons not apparent in his medical or surgical history. General anesthesia was administered during 264 procedures, combined epidural and general anesthesia was administered during 2 procedures, and epidural anesthesia alone was administered in 1 procedure. As a group, these children had undergone a total of 1646 surgical procedures, including those in this report, an average of 10.2 +/- 4.7 surgical procedures each. All patients were treated according to the protocol previously established in our department ^[7] (Table 3). Patients did not receive any premedication with histamine antagonists or corticosteroids for allergy prophylaxis.

Physiological responses during surgery from all patients were recorded consecutively as a concurrent audit. Blood pressure and heart rate data were calculated as the percent difference from preanesthetic baseline for each patient and displayed against elapsed time from the start of surgery. Oxygen saturation (Nellcor N-200[registered sign]; Nellcor Incorporated, Hayward, CA) and end-tidal carbon dioxide level in millimeters of mercury (Capnomac Ultima[registered sign]; Datex, Helsinki, Finland) were recorded for each patient throughout surgery.

Results

One patient of 162 (1 procedure of 267) had an intraoperative anaphylactic reaction manifested by urticaria, hypotension, and wheezing after injection of an epidural catheter with bupivacaine 0.125% and fentanyl 2 micro g/mL. This syringe, with a latex stopper, had been prepared in our pharmacy 1.5 weeks earlier. The surgical procedure had been underway for 4.5 h, and the patient, anesthetized with isoflurane in oxygen and air and with pancuronium for neuromuscular block, had been stable until shortly after the injection of the epidural catheter, which had not yet been injected with medication from this syringe. Intravenous (IV) cefazolin reconstituted with normal saline in a multidose vial with the stopper removed, had been administered earlier, but not within 3 h of the injection of the epidural catheter. Within minutes of the injection of the epidural catheter, this patient developed hypotension, with systolic and diastolic blood pressure less than 35% of baseline, unresponsive to fluid administration. There was also an increase in peak inspiratory airway pressure with mild wheezing bilaterally. Urticaria were present on his arms and chest as well as on his abdomen, as seen from within the surgical field. The anaphylactic reaction resolved within 30 min, responding to several doses of 0.1 micro g/kg of epinephrine and a brief continuous infusion of 0.01 micro g [center dot] kg^-1 [center dot] min^-1 of epinephrine as well as general supportive care. The patient received an analgesic mixture of bupivacaine 0.125% and fentanyl 2 micro g/mL, freshly prepared in a nonlatex stopper syringe, during the perioperative period without any adverse reaction.

No other procedure was complicated by urticaria, wheezing, or instability of vital signs. End-tidal carbon dioxide levels and oxygen saturation remained normal throughout all 267 surgical procedures, and all patients recovered uneventfully in the perioperative period.

Discussion

The most common first presentations of latex allergy, as ascertained by patient history, were intraoperative anaphylaxis during previous surgery, an allergic reaction at the dentist's office, or an allergic reaction to latex balloons. Almost all patients or their families (161 of 162) could recall a specific event that led to the suspicion of latex allergy, which was confirmed in most patients by in vivo or in vitro techniques, although not all families accepted the offer to document the diagnosis (Table 1). Anaphylaxis in the operating room occurred in 26% of the patients (71% were validated by allergy testing, 29% declined testing). In addition, 22% of the patients had allergic reactions at the dentist's office (80% were validated by allergy testing, 20% declined testing), and 17% of the patients had allergic reactions to latex balloons (52% were subsequently validated by allergy testing, 48% declined testing). Although not all patients with a positive history were proven latex-allergic by in vivo or in vitro testing, no previously symptomatic patient in this high-risk population had ever had a negative latex allergy test, regardless of the method of investigation used. The sensitivity of the history alone in this at-risk population may have led a sizable minority of parents to decline further allergy evaluation when weighing the information to be gained against the knowledge of their child's response to latex exposure.

Children with myelodysplasia or congenital urological anomalies are particularly susceptible to developing latex allergy, with an estimated overall prevalence from 18% to 73% ^[9,15]. When avoiding latex materials or only using older, washed latex materials, such as ventilator bellows ^[7], there were no signs of intraoperative anaphylaxis in 266 of the 267 procedures in our latex-allergic patients. With a virtually identical latex-avoidance protocol, Birmingham et al. ^[16] found an incidence of latex allergy of 4% before the protocol was instituted, decreasing to 1.2% after the latex-avoidance protocol was instituted. Of this 1.2%, three of the five patients were accidentally exposed to latex products by the surgical or anesthesia team. In the initial report of latex allergy from our institution ^[17], hypotension, flushing, and bronchospasm were seen during 3.8% (11 of 288) of procedures in patients with myelodysplasia; no latex-avoidance precautions were used during this time period (P = 0.013 compared with this report, chi squared with correction for continuity). Moreover, in the five-year period from 1988 to 1993, 36 of 875 (4.1%) surgical procedures were complicated by intraoperative signs of an allergic reaction, notwithstanding the use of a latex-avoidance protocol at our institution for three of those five years ^[7] (P = 0.006 compared with this report, chi squared with correction for continuity). As experience with latex avoidance was acquired, it became easier to avoid the human errors that most consistently accounted for these allergic reactions ^[14]. With a latex-safe protocol in place, latex allergic patients can therefore be expected to experience an allergic reaction 0%-0.3% of the time in the absence of protocol violations.

The immune expression of latex allergy in adults may differ from that in children. Myelodysplasia patients have a greater proportion of IgE antibodies to a 27-Kd peptide, whereas health-care workers with latex allergy produce IgE with a greater proportion of antibodies to a 20-Kd peptide ^[18]. Although the diagnosis of latex allergy is made by a combination of medical history, physical examination, and reliable in vivo or in vitro tests, latex allergy testing may be of particular importance for adults who have developed signs and symptoms of latex intolerance in the workplace and who wish to confirm the diagnosis before surgery. It is possible that the environmental control, use of washed latex equipment, and avoidance of chemoprophylaxis are appropriate and successful for children, but they may not be adequate for preventing anaphylaxis in latex-allergic adults.

We continued our policy of avoiding allergy-attenuating premedication ^[7,14]. There is no evidence that supports the use of premedication with antihistamines or steroids to prevent IgE-mediated reactions when the antigen itself can be avoided ^[10,19]. Indeed, premedication has failed to prevent latex anaphylaxis ^[13,16]. The patients' chronic medication regimens consisted primarily of prophylactic antibiotics and anticholinergics for the urinary tract, not medications such as steroids or antihistamines that affected their allergy responsiveness.

Latex-allergic patients often have many additional allergies and sensitivities. Antibiotic allergies, primarily to those antibiotics used to sterilize the urinary tract, were by far the most common medication allergies reported in our population, with 222 occurrences. Several patients had allergy signs and symptoms and positive intradermal tests to morphine, fentanyl, lidocaine, pancuronium, and succinylcholine. Although cross-reactivity of latex and tropical fruit allergies is not uncommon ^[20-23], and although tropical fruit allergy may raise suspicion about a patient's potential for latex allergy, we found few children allergic to tropical fruits.

It is of utmost importance to recognize the role of human error when caring for latex-allergic patients. The single reaction to latex in 267 episodes of surgery was attributable to the use of a routine clinical practice for our patients without latex allergy. Underscoring our findings and the difficulty in altering clinical habits, violations of a latex-avoidance protocol accounted for most of the anaphylactic reactions in another recently published series of children with myelodysplasia and latex allergy ^[16].

In conclusion, although anaphylactic reactions are rare during anesthesia, their high incidence of morbidity and mortality makes these reactions a major concern. For children who have had serious allergic reactions to latex, a latex-safe environment is effective in preventing perioperative anaphylaxis. Latex-allergic patients require the avoidance of latex products or the use of safe latex products that have been previously used and thoroughly washed. Careful attention to usual habits with avoidance of exposure to potential sources of latex antigen must be maintained at all times. The administration of chemoprophylaxis for the attenuation of an allergic response is unnecessary, whereas the avoidance of human error remains paramount.