Gastrointestinal permeability following cardiopulmonary bypass: a randomised study comparing the effects of dopamine and dopexamine

Abstract

Objective: To compare the effects of dopexamine and dopamine on the mucosal permeability of the gastrointestinal tract (GIT).

Design: Prospective, randomised clinical trial.

Setting: Intensive care unit of a postgraduate teaching hospital, London, England.

Patients: Thirty patients undergoing elective surgery involving cardiopulmonary bypass, performed by a single surgeon.

Interventions: Patients were randomly assigned to receive either dopexamine 2.0 micrograms/kg per min or dopamine 2.5 micrograms/kg per min for the duration of the study period.

Measurements and main results: Hemodynamic parameters and gastric intramucosal pH (pHi) were measured at intervals throughout the study. GIT permeability was measured once, post-operatively, using the ratio of absorbed lactulose to L-rhamnose. The groups were similar with respect to demographics, pre- and post-operative risk factors. The lactulose/rhamnose ratio was (mean +/- SEM) 0.44 +/- 0.10 in the dopexamine group vs 0.65 +/- 0.08 in that receiving dopamine (p < 0.05). The dopexamine group had a significantly higher oxygen delivery preoperatively (479.5 +/- 32.0 ml/min per m2 vs 344.4 +/- 23.9 ml/min per m2 for dopamine, p < 0.01), but no other significant differences emerged between the groups.

Conclusions: Compared to dopamine, dopexamine reduces GIT permeability following surgery involving cardiopulmonary bypass. The mechanism of this effect remains unclear.