Comparison of a fixed dose of 0.15% Hypobaric and 0.5% Hyperbaric Bupivacaine for shortterm unilateral lower limb orthopedic surgeries.Retrospective study with two videos

Background: Unilateral spinal anesthesia in orthopedic surgery of a limb has its advantages, especially in patients undergoing outpatient basis surgeries. Low dose, slow speed of administration and remaining in lateral decubitus for a certain period facilitate unilateral distribution in spinal anesthesia. Isobaric solutions of local anesthetics are not suitable for this type of anesthesia. Hypobaric and hyperbaric solutions of bupivacaine were compared in unilateral spinal anesthesia in patients undergoing orthopedic surgeries of one limb on an outpatient basis. Methods: Retrospective study carried out between 2002 and 2020 with 497 patients were randomly divided into two groups to receive 6 mg of 0.15% hypobaric bupivacaine or 6 mg of 0.5% hyperbaric bupivacaine. The solutions were administered in the L3-L4 space with the patient in the left lateral decubitus and remaining in this position for 15 minutes. Sensitive anesthesia was evaluated by the pin prick test. Motor blockade was determined by the modified Bromage scale. Both blockades were compared with the opposite side and among themselves. Results: There was a significant difference between the side of the surgery and the opposite side in all two groups at 15 minutes, but the frequency of unilateral spinal anesthesia was 90.9% with the 0.15% hypobaric bupivacaine versus 93.2% with the 0.5% hyperbaric bupivacaine. Patients did not develop any hemodynamic changes. Post puncture headache and transitory neurological symptoms were not observed. Conclusion: Spinal anesthesia with hypobaric and hyperbaric solutions present a higher frequency of unilateral anesthesia, without cardiocirculatory alteration, and patient satisfaction in remaining with a limb without anesthesia.