Acute High Spinal Block After Subarachnoid Anesthesia During Lower Limb Surgery: A Case Report

Background: High spinal block is a rare but potentially life-threatening complication of subarachnoid anesthesia resulting from excessive cephalad spread of local anesthetic within the cerebrospinal fluid. It can rapidly progress to profound hypotension, bradycardia, respiratory insufficiency, and cardiovascular collapse if not recognized and managed promptly. Early diagnosis and immediate resuscitative intervention are essential to ensure favorable outcomes. Case Presentation: We report the case of a 45-year-old male who underwent open reduction and internal fixation for a right tibial shaft fracture under subarachnoid anesthesia with 0.5% hyperbaric bupivacaine. Within minutes of intrathecal injection, the patient developed rapidly ascending sensory blockade, severe hypotension, bradycardia, respiratory distress, and oxygen desaturation, consistent with high spinal block. Immediate management included administration of 100% oxygen, rapid intravenous fluid resuscitation, atropine, vasopressor support, endotracheal intubation, and controlled mechanical ventilation. The patient remained hemodynamically stable following resuscitation, demonstrated gradual neurological recovery, and was successfully extubated after complete regression of the spinal block. He was discharged without neurological, cardiovascular, or respiratory sequelae. Conclusion: High spinal block remains an uncommon but serious complication of spinal anesthesia that requires rapid recognition and immediate intervention. Careful patient monitoring during the immediate post-spinal period, early airway stabilization, aggressive hemodynamic support, and adherence to established anesthetic guidelines are essential for preventing morbidity and ensuring successful recovery. This case highlights the importance of preparedness for airway emergencies and reinforces the need for prompt multidisciplinary management of this potentially reversible anesthetic complication. Keywords: High spinal block; Subarachnoid anesthesia; Spinal anesthesia; Hypotension; Bradycardia; Airway management; Mechanical ventilation; Lower limb surgery; Case report.