Routine Antiemetic Prophylaxis for Nonfasted Parturients Undergoing Cesarean Sections Under Spinal Anesthesia

The aim of this prospective randomized double-blind study is to compare the effectiveness of routine antiemetic prophylaxis for the prevention of intraoperative nausea and vomiting (IONV) in non-fasted parturients undergoing emergency cesarean section under spinal anesthesia. Nausea and vomiting are common complications during cesarean delivery performed under spinal anesthesia and may negatively affect maternal comfort and perioperative safety. The incidence of these symptoms may be particularly increased in emergency cesarean sections involving non-fasted (full-stomach) parturients. This study compares two commonly used antiemetic strategies, namely 5-hydroxytryptamine-3 (5-HT3) receptor antagonists and dopamine receptor antagonists, to determine their relative effectiveness in preventing IONV during surgery. The findings are expected to contribute to optimization of antiemetic prophylaxis protocols, improvement of maternal comfort, and reduction of perioperative complications associated with nausea and vomiting during emergency cesarean delivery.

Inclusion Criteria: * Pregnant women scheduled for emergency cesarean delivery under spinal anesthesia * Non-fasted (full-stomach) parturients * American Society of Anesthesiologists (ASA) physical status I-II * Age ≥ 18 years * Singleton pregnancy * Ability to provide written informed consent Exclusion Criteria: * ASA physical status III or higher * Refusal to participate * Elective cesarean delivery (non-emergency cases) * Preoperative antiemetic use within 24 hours before surgery * Known allergy or contraindication to study drugs (ondansetron or metoclopramide) * Pre-existing gastrointestinal disorders (e.g., severe GERD, gastroparesis, bowel obstruction) * Psychiatric illness or current use of psychotropic medications * Preoperative anemia (as defined by institutional threshold, e.g., Hb \< 10 g/dL) * Intraoperative conversion to general anesthesia * Massive intraoperative hemorrhage (\>1000-1500 mL or requiring transfusion, depending on your protocol definition) * Intraoperative administration of additional sedative or antiemetic agents outside study protocol * Multiple gestation pregnancies