Sevoflurane and propofol anaesthesia differentially modulate the effects of epinephrine and norepinephrine on microcirculatory gastric mucosal oxygenation.

BACKGROUND

Adequate gastrointestinal mucosal oxygenation is regarded to be crucial in the prevention and therapy of critical illness. Epinephrine and norepinephrine are used for perioperative haemodynamic support. However, their per se effects on gastromucosal haemoglobin oxygenation (μHbO(2)) remain unclear. Moreover, respective effects of epinephrine and norepinephrine may be affected by the type of underlying anaesthesia. Thus, we studied the effects of epinephrine and norepinephrine during anaesthesia with sevoflurane or propofol on regional gastromucosal μHbO(2) and systemic O(2)-derived variables.

METHODS

In a double-randomized cross-over study, chronically instrumented dogs (n=6 per group) were anaesthetized randomly with sevoflurane or propofol, ventilated, and then randomly received either epinephrine or norepinephrine (0, 0.05, 0.1, and 0.2 µg kg(-1) min(-1)). We measured gastromucosal μHbO(2), systemic haemodynamics, and O(2)-derived variables.

RESULTS

During sevoflurane anaesthesia, norepinephrine markedly increased μHbO(2) (P<0.0001) and systemic oxygen transport (DO(2)) (P=0.0006). In contrast, epinephrine failed to increase μHbO(2), despite doubling DO(2) (P=0.0002). During propofol anaesthesia, in contrast to sevoflurane, neither epinephrine nor norepinephrine affected μHbO(2), although epinephrine, but not norepinephrine, again resulted in markedly increased DO(2) (P<0.0001).

CONCLUSIONS

The effects of epinephrine and norepinephrine depended on the type of anaesthesia. In addition, regional effects (i.e. μHbO(2)) were not predictable from systemic effects (i.e. DO(2)).