Incidence and Associated Factors of Hypotension Following Spinal Anaesthesia in Elective Lower-Limb and Lower-Abdominal Surgeries: A Retrospective Observational Study
Keywords:
Spinal Anaesthesia, Hypotension, Bupivacaine, Hypertension, Vasopressor, Retrospective Study.Abstract
Background: Hypotension is a frequent haemodynamic complication of spinal anaesthesia and may be particularly important in older patients and those with cardiovascular comorbidity.
Objective: To estimate the incidence of hypotension after spinal anaesthesia and examine its unadjusted associations with routinely recorded demographic, clinical and anaesthetic variables.
Methods: This retrospective observational analysis included 50 elective surgical patients who received spinal anaesthesia. Hypotension was defined as systolic blood pressure <90 mmHg or a >30% reduction from baseline during the intraoperative or immediate postoperative period. Fisher exact tests were used for binary categorical comparisons and Mann-Whitney U tests for continuous variables. Multivariable regression was not performed because several predictors showed complete separation and strong collinearity.
Results: Hypotension occurred in 26/50 patients (52.0%; 95% CI 38.5-65.2%). Patients with hypotension were older (median 59.5 vs 36.5 years), had higher BMI (30.2 vs 25.0 kg/m²) and higher baseline systolic pressure (151 vs 123 mmHg), all p<0.001. Hypotension occurred in all 26 patients with hypertension and none of 24 without hypertension (p<0.001), and in all 12 patients with diabetes compared with 14/38 without diabetes (p<0.001). ASA II-III status and the L2-L3 puncture interspace were also strongly associated with hypotension. All 26 hypotensive patients received vasopressor therapy.
Conclusion: Hypotension affected approximately half of this cohort and clustered among older patients with greater comorbidity and higher ASA status. The observed associations with puncture interspace and bupivacaine dose were strongly confounded by patient and procedural selection and should not be interpreted causally. Larger datasets with detailed haemodynamic and anaesthetic records are required for adjusted risk modelling.
