Tourniquet induced hypertension, defined as a more than 30% increase in either systolic or diastolic arterial pressure in patients with a tourniquet inflated for at least an hour, may develop despite adequate anesthesia for surgical procedure. The mechanism is uncertain. We investigated the effect of stellate ganglion block (SGB) on tourniquet induced arterial pressure and heart rate changes.

Twenty-two patients of ASA physical status class 1 and 2, scheduled for lower extremity surgery using a tourniquet, were randomly assigned into two groups (SGB group, Control group). SGB was done before induction, and anesthesia was maintained with 1.5-2.0 vol% sevoflurane and 50% N₂0 in O₂ with endotracheal intubation. The changes of heart rate, systolic, diastolic blood pressure, end tidal CO₂ and end tidal sevoflurane concentration were measured before induction, 10 minutes after induction, 10, 30, and 60 minutes after tourniquet inflation, just before tourniquet deflation and 10 minutes after tourniquet deflation.

Heart rate increased significantly at 10 minutes after induction and 10 minutes after tourniquet inflation compared to before induction in SGB group. In both groups, systolic arterial pressure increased significantly just before tourniquet deflation compared to before induction, and there was no difference between groups. In SGB group, diastolic arterial pressure decreased significantly compared to control group at 30 minutes after tourniquet inflation.

Preoperative stellate ganglion block was not effective in blunting tourniquet induced hypertension.