Incidence of Hypotension in Patients Undergoing Subarachnoid Block in Sitting versus Lateral Decubitus Position in Elective Lower Limb Surgeries.

Background Subarachnoid block (SAB) is a widely practiced regional anesthetic for lower limb surgeries. The patient position for subarachnoid block induction, either sitting or lateral decubitus, may affect hemodynamic stability and block quality. Objective To compare the incidence of hypotension and the onset times of block in these two positions. Method In this prospective single-center observational comparative study, 108 patients, who were scheduled to undergo elective lower limb surgery, were equally assigned to subarachnoid block in sitting position (SP) and Lateral decubitus position (LP) groups. An intrathecal dose of hyperbaric Bupivacaine 0.5% (15 mg) was given. Hemodynamic variables, onset of sensory and motor block, maximum level of sensory and motor block and any complications including hypotension and bradycardia were recorded and compared. Categorical variables were analyzed using the Chi-square test, and continuous variables were compared using the unpaired Student's t-test. Result The incidence of hypotension was greater in sitting position group (20.41%) than in LP group (16.67%), but the difference was not statistically significant. Out of these, bradycardia was more frequent in sitting position (9.2%) as compared to lateral decubitus position (7.4%). The onset times of sensory and motor blocks in the lateral decubitus position group were significantly shorter (p < 0.05). Conclusion Lateral decubitus position results in superior early hemodynamic stability and shorter time to sensory and motor block onset as compared to sitting in subarachnoid block for elective lower limb surgeries.