Perioperative plasma volume expansion reduces the incidence of gut mucosal hypoperfusion during cardiac surgery

Abstract

Objective: To test the hypothesis that perioperative plasma volume expansion would preserve gut mucosal perfusion during elective cardiac surgery.

Design: Prospective randomized open study.

Setting: Teaching hospital.

Patients: Sixty American Society of Anesthesiology grade III patients with a preoperative left ventricular ejection fraction of 50% or greater undergoing elective cardiac surgery.

Interventions: Patients were allocated randomly to a control or protocol group. The control group was treated according to standard practices. After induction of general anesthesia, the protocol group received, in addition, 200-mL boluses of a 6% hydroxyethyl starch solution to obtain a maximum stroke volume. This procedure was repeated every 15 minutes until the end of surgery, except when the patient underwent cardiopulmonary bypass.

Measurements and results: Cardiac stroke volume was estimated by an esophageal Doppler system, and gastric mucosal perfusion was measured by tonometric assessment of gastric intramucosal pH in all patients. Patients were followed up postoperatively until discharge from the hospital or death. The incidence of gut mucosal hypoperfusion (gastric intramucosal pH < 7.32) at the end of surgery was reduced in the protocol group (7% vs 56%) (P < .001), as were the number of patients in whom major complications developed (0 vs 6) (P = .01), mean number of days spent in the hospital (6.4 [range, 5 to 9] vs 10.1 [range, 5 to 48]) (P = .011), and mean number of days spent in the intensive care unit (1 [range, 1 to 1] vs 1.7 [range 1 to 11] days) (P = .023).

Conclusions: Perioperative plasma volume expansion with colloid during cardiac surgery, guided by esophageal Doppler measurement of cardiac stroke volume, reduced the incidence of gut mucosal hypoperfusion. This group of patients also had an improved outcome when compared with controls.