Dopexamine does not improve jejunal or gastric tube mucosal perfusion following oesophageal resection

Background

There is conflicting evidence that dopexamine hydrochloride exerts a selective vasodilating effect upon the gastrointestinal mucosa. Whilst some human studies conducted in the critically ill and in high risk surgical patients have suggested that dopexamine may cause an increase in tonometrically measured gastric intra-mucosal pH (pHi) and an improvement in clinical outcome, this has not been confirmed in our randomised trials. Furthermore, there are no previously published reports of the effect of dopexamine on human small bowel mucosal perfusion. An increase in splanchnic perfusion in general or gastric mucosal perfusion in particular following oesophageal resection may potentially reduce the incidence of anastomotic leaks and structures as these complications are thought to be caused by hypoperfusion and consequent tissue hypoxia at the gastric end of the oesophagogastric anastomosis. This study assessed the effect of dopexamine on gastric tube and jejunal mucosa pHi measured tonometrically following oesophagectomy.

Methods

Twelve patients undergoing oesophageal resection for carcinoma and reconstitution of gastrointestinal continuity using a gastric tube were randomised into dopexamine and control groups. During surgery tonometer balloons (Tonometric Division, Instrumentarium Division, Helsinki, Finland) were placed 5 cm distal to the anastomosis within the stomach and 10 cm during the duodeno-jejunal flexure within the jejunum. These were connected to separate `Tonocap' analysers (Datex, Helsinki, Finland). 24 h following surgery all the patients were sedated, ventilated and cardiovascularly stable. Three measurements of heart rate, mean arterial pressure, central venous pressure as well as gastric and jejunal pHi were made at 30 min intervals prior to the commencement of an intravenous infusion of either dopexamine (2 μg/kg/min) or of a placebo. Four further sets of measurements were made at 30 min intervals during the infusion, and after 2 h it was stopped and three measurements over the next 90 min were made. The results were analysed using the Mann–Whitney test for non-parametric data.

Results

There were no significant changes in systemic arterial or central venous pressure in either group during the study. However, in the dopexamine group there was a significant increase in mean (SD) heart rate from 85 (12) to 104 (10) beats per minute during the infusion and a subsequent fall to 94 (10) beats per minute after its cessation (in both cases P < 0.005). There were no significant changes in either gastric or jejunal pHi during dopexamine or placebo infusion (in all cases P > 0.05).

Conclusion

Dopexamine hydrochloride does not increase gastric tube pHi following oesophagectomy. Furthermore there is no evidence from this study that dopexamine is capable of influencing jejunal mucosal perfusion, and its potential role not only in protecting gastrointestinal anastomoses but also in reducing mortality due to MODS by directly influencing splanchnic perfusion is not supported by the findings of this study.

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