Dexamethasone and Duration of Spinal Anesthesia

This study will evaluate whether intravenous dexamethasone affects the duration of spinal anesthesia in patients undergoing lower abdominal surgery. Eligible adult patients classified as ASA I or II will undergo routine preoperative assessment by an anesthetist. Before surgery, patients will receive either intravenous dexamethasone (8 mg diluted in 100 mL normal saline) or 100 mL normal saline alone. The medication will be administered through a peripheral intravenous cannula. Spinal anesthesia will then be performed using a standard technique. A 25-gauge spinal needle will be used to administer 12-15 mg of 0.75% hyperbaric bupivacaine into the lower lumbar region while the patient is in the sitting position. After confirming the flow of cerebrospinal fluid, the patient will be positioned for surgery. The level and effectiveness of anesthesia will be assessed using standard sensory and motor assessments. Surgery will begin after an adequate level of numbness and motor block has been achieved. The recovery of sensory and motor function will subsequently be assessed at regular 15-minute intervals by an anesthesia team member who was not involved in administering the spinal anesthesia, to minimize assessment bias. The main outcome will be the time required for the sensory block to regress from its initial level to the lower thoracic region (T10-T12). Additional outcomes will include the total duration of sensory and motor block and postoperative pain, assessed using a visual pain scale four hours after surgery. Patient information such as age, sex, diagnosis, type of surgery, duration of sensory and motor block, and postoperative pain score will be recorded and analyzed to determine whether intravenous dexamethasone prolongs the duration of spinal anesthesia.