Background factors for intra-operative hypotension during hip fracture repair surgery in the elderly under spinal anesthesia managed by orthopedic surgeons: A retrospective case-control study

•The higher the puncture level of lumbar anesthesia, the more likely hypotension is to occur.•Diuretic medication is a risk for spinal anesthesia-induced hypotension.•Bupivacaine doses in the range of 8–14 mg were not associated with intraoperative vasopressor use. Spinal anesthesia is used for femoral trochanteric fracture surgery, but frequently induces hypotension and the causative factors remain unclear. We examined background factors for the use of an intraoperative vasopressor in elderly patients receiving spinal anesthesia for femoral trochanteric fracture surgery. We retrospectively analyzed 203 patients >75 years (mean age, 87.9 years) with femoral trochanteric fractures who underwent short nail fixation under orthopedically managed spinal anesthesia at our hospital between April 2020 and July 2023. Patients were divided into two groups: group A (intraoperative vasopressor) and group B (no vasopressor). The following data were compared: age, sex, height, weight, body mass index, antihypertensive medication, years of experience as a primary surgeon, bupivacaine dose, puncture level, anesthesia time, operation time, hemoglobin level and blood urea nitrogen/creatinine ratio on the day of surgery, brain natriuretic peptide level, left ventricular ejection fraction, and percentage of patients operated on the day of transport. There were 65 patients in group A and 138 in group B. The average dose of bupivacaine was 11.7 mg. In a univariate analysis, group A was slightly younger (87.0 vs. 88.3 years), had a higher blood urea nitrogen/creatinine ratio (27.1 vs. 24.5), more frequently received β-blockers (14.1% vs. 5.8 %) and diuretic medications (21.9% vs. 11.6 %), and had a higher puncture level. A logistic regression analysis identified younger age (p = 0.02) and diuretic medication (p = 0.001) as independent risk factors in group A. Vasopressor use was more frequent at a higher puncture level in group A (57 % for L2/3, 33 % for L3/4, 15 % for L4/5, 0 % for L5/S). Spinal anesthesia-induced hypotension is attributed to volume deficit or extensive sympathetic blockade and may be prevented by avoiding high puncture levels and increasing preoperative fluid supplementation in patients on diuretics. There is currently no consensus on anesthetic dosages.