Following surgery to remove tumours of the head and neck, patients undergo reconstruction with free flaps - tissue that is taken from elsewhere in the body and given a new blood supply by attaching it to vessels in the neck. Following this type of surgery, patients often need medication to maintain their blood pressure in the intensive care unit. The effect of these drugs on the transplanted tissues is unknown. This study investigates the effects of four commonly used drugs on free flap perfusion.

The optimal sympathomimetic drug to support blood pressure without adverse vasoconstriction of free flap circulation remains unknown. This study examined the effects of four agents (epinephrine, norepinephrine, dobutamine and dopexamine) on free flaps following resection of head and neck cancer.

Twenty five patients were recruited to the study. Each patient received an infusion of the four drugs in a random order with an intervening washout period between drugs, at four infusion rates. Continuous free flap skin blood flow monitoring was performed using laser Doppler velocimetry, with a second sensor on normal skin acting as a control. Global cardiovascular variables were monitored using the LiDCO Rapid pulse contour analysis system.

Inclusion Criteria:

• Patients undergoing free tissue transfer surgery at the John Radcliffe Hospital wih planned post-operative admission to the intensive care unit.

Exclusion Criteria:

• Pregnancy
• Weight >100kg
• Contraindications to pressor infusions
• Overnight ventilation not indicated