Effect of Injection Speed of Heavy Bupivacaine in Spinal Anesthesia on Quality of Block and Hemodynamic Changes

Spinal anesthesia is a technique widely used for gynecological, lower abdominal, pelvic and lower limb procedures. Even though it causes a profound nerve block, it is associated with profound hypotension. To assess the effect of the speed of injection of heavy bupivacaine on quality of block and hemodynamic changes in patients undergoing gynecological surgeries under spinal anesthesia. This was a prospective randomized study conducted on 40 patients. Group F patients were given 3.2 mL of 0.5% heavy bupivacaine intrathecally in 15 s and Group S patients were given the same drug over 60 s. The time to achieve T dermatomal block, maximum block height, block height at 5 min were recorded. Heart rate (HR), systolic, diastolic blood pressures, and mean arterial pressures (MAP) were also recorded at different time points. HR, systolic BP, diastolic BP, and MAPs and mean block height at 5 min were comparable between the two groups at all time points. The time to achieve T dermatome block was significantly faster in Group F (1.85 ± 1.14 min) as compared to Group S (3.98 ± 1.58 min). Majority of patients in Group F (65%) had a maximum block up to T and those in Group S (45%) had a block upto T . The usage of vasopressors was found to be significantly higher in Group F compared to Group S with = 0.041. Using faster speed of injection of heavy bupivacaine during spinal anesthesia can lead to faster achievement of blockade but with significantly higher usage of vasopressors.