Controlled hypotension and minimal inflation pressure: a new approach for pneumatic tourniquet application in upper limb surgery.

Abstract

Minimal inflation pressures are recommended for limb surgery to eliminate complications attributable to high inflation pressures with the pneumatic tourniquets. We applied controlled hypotension and a minimal inflation pressure (CHAMIP) technique to provide a bloodless surgical field. Thirty-six patients scheduled for upper extremity surgery were randomized equally to receive either normotensive anesthesia and conventional inflation pressures or controlled hypotension (systolic arterial blood pressure of 80-100 mm Hg and mean arterial blood pressure >60 mm Hg) and minimum inflation pressures. Anesthesia was induced with propofol IV bolus and remifentanil IV continuous infusion and maintained with propofol and remifentanil IV continuous infusion. To determine the minimal inflation pressure, the digital plethysmograph was applied to the second finger at the side of the operation and the tourniquet was inflated slowly until the arterial pulsations disappeared on the oscilloscope. A bloodless surgical field was obtained in almost all patients, even though systolic arterial blood pressures (100-138 mm Hg versus 80-100 mm Hg) and applied tourniquet inflation pressures (270 mm Hg versus 110-140 mm Hg) were significantly lower in the hypotensive group. No complications associated with controlled hypotension were encountered. In conclusion, CHAMIP may be a safe and reliable method for upper extremity surgery performed with pneumatic tourniquets. Pneumatic tourniquets are associated with adverse effects resulting from high inflation pressures. Therefore, minimal inflation pressures are recommended in extremity surgery. To reach real minimal inflation pressure the patient's blood pressure must be reduced. We used controlled hypotension with remifentanil and propofol to reach minimal inflation pressures.