Acute effect of fentanyl on haemodynamics and myocardial carbohydrate utilization and phosphate release during ischaemia.

The effect of fentanyl 25 micrograms/kg body weight i.v. on left ventricular haemodynamics, myocardial carbohydrate utilization and phosphate release during ischaemia in dogs was investigated. A reproducible degree of ischaemia could be obtained by partial occlusion (stenosis) of the interventricular artery, using an inflatable cuff. Inducing stenosis twice made it possible to use the animal as its own control. Arterio-local venous differences of glucose increased during ischaemia and lactate and inorganic phosphate were released from the ischaemic myocardium. Fentanyl administered before the second stenosis reduced heart rate and, to a lesser extent, mean aortic pressure and left ventricular dP/dt max. The release of lactate and inorganic phosphate was diminished during the period of ischaemia. These findings suggest that fentanyl prevents excessive breakdown of energy-rich phosphates and high anaerobic production rate of lactate by decreasing the energy demand of the ischaemic myocardium.