Spinal anesthesia and management
hypotension
QUINCKE, COLD, DECUBITUS
All patients received routine preoperative care without premedication. On arrival in the operating room, standard monitoring was initiated, including noninvasive automated blood pressure, electrocardiography, and pulse oximetry. Spinal anesthesia was induced in the lateral decubitus position using a 25-gauge Quincke spinal needle and 10-12 mg of hyperbaric 0.5% bupivacaine in the L3/L4 or L4/L5 intervertebral space. The level of sensory block was assessed using cold sensitivity to alcohol swabs 10 min after intrathecal injection. After achieving an adequate sensory block (at the T10 level), the patients were prepared for surgery, and oxygen was administered at 3 L/min via a nasal cannula. Spinal anesthesia-induced hypotension was defined as a systolic BP (SBP) < 90 mmHg and a decrease in baseline SBP > 20% after the intrathecal injection. The patient was initially treated with 200 mL of a balanced crystalloid solution when hypotension occurred. When hypotension persisted for 3 min, 5 mg of ephedrine was administered intravenously and repeated every 3 min, depending on the subsequent improvement. Patients with incomplete or high-level spinal anesthesia (sensory block level > T4) and low blood pressure (systolic blood pressure < 90 mmHg) that persisted despite appropriate treatment were excluded from the study.