Background: Evidence-based guidelines on optimal perioperative fluid management have not been established, and recent randomized trials in major abdominal surgery suggest that large amounts of fluid may increase morbidity and hospital stay. However, no information is available on detailed functional outcomes or with fast-track surgery. Therefore, we investigated the effects of two regimens of intraoperative fluids with physiological recovery as the primary outcome measure after fast-track colonic surgery.

Methods: In a double-blind study, 32 ASA I-III patients undergoing elective colonic surgery were randomized to 'restrictive' (Group 1) or 'liberal' (Group 2) perioperative fluid administration. Fluid algorithms were based on fixed rates of crystalloid infusions and a standardized volume of colloid. Pulmonary function (spirometry) was the primary outcome measure, with secondary outcomes of exercise capacity (submaximal exercise test), orthostatic tolerance, cardiovascular hormonal responses, postoperative ileus (transit of radio-opaque markers), postoperative nocturnal hypoxaemia, and overall recovery within a well-defined multimodal, fast-track recovery programme. Hospital stay and complications were also noted.

Results: 'Restrictive' (median 1640 ml, range 935-2250 ml) compared with 'liberal' fluid administration (median 5050 ml, range 3563-8050 ml) led to significant improvement in pulmonary function and postoperative hypoxaemia. In contrast, we found significantly reduced concentrations of cardiovascularly active hormones (renin, aldosterone, and angiotensin II) in Group 2. The number of patients with complications was not significantly different between the groups [1 ('liberal' group) [corrected] vs 6 ('restrictive' group) [corrected] patients, P = 0.08].

Conclusions: A 'restrictive' [corrected] fluid regimen led to a transient improvement in pulmonary function and postoperative hypoxaemia but no other differences in all-over physiological recovery compared with a 'liberal' [corrected] fluid regimen after fast-track colonic surgery. Since morbidity tended to be increased with the 'restrictive' fluid regimen, future studies should focus on the effect of individualized 'goal-directed' fluid administration strategies rather than fixed fluid amounts on postoperative outcome.