It has been suggested that the incidence of tourniquet pain is less frequent in patients in whom bupivacaine has been employed for spinal anesthesia than in patients to whom tetracaine has been administrated. The current study was accomplished to compare the incidence of tourniquet pain in patients in whom 0.5% plain bupivacaine spinal anesthesia and 0.5% hyperbaric tetracaine spinal anesthesia were employed.

The incidence of tourniquet pain was evaluated in 40 patients having orthopaedic surgery of the lower extremities during spinal anesthesia using 15 mg of hyperbaric 0.5% tetracaine(group I) or 15 mg of a plain solution of 0.5% bupivacaine(group II). The drugs were administrated in a randomized fashion. We measured the maximal sensory spread of analgesia to pinprick test, the incidence of tourniquet pain, the sensory anesthesia to pinprick test at time of onset of tourniquet pain and the number of patient treated with IV injection of fentanyl to relieving tourniquet pain.

The maximal sensory spread of analgesia mean was higher in patients given hyperbaric tetracaine (T8) than in patients given plain bupivacaine (T9). The incidence of tourniquet pain was significantly greater in patients given hyperbaric tetracaine (65%) than in patients given plain bupivacaine (15%). The incidence of analgesics injection for tourniquet pain was greater in patients given hyperbaric tetracaine (10%) than in patients given plain bupivacaine (none).

In conclusion, the tourniquet pain in surgery of the lower extremities occurs less frequently when plain bupivacaine is employed for spinal anesthesia as compared to hyperbaric tetracaine.