After approval from the departmental research committee and College of Physicians and Surgeons Pakistan (CPSP), all pediatric patients fulfilling the inclusion criteria undergoing elective outpatient infra-umbilical surgery under general anesthesia combined with caudal analgesia at Aga Khan University Hospital would be enrolled for this study. Informed parental consent will be taken after explaining the purpose and procedure of the study.

All patients will be assessed preoperatively for anesthesia fitness by history, physical examination and laboratory investigations. On arrival on the day of surgery, patient will be premedicated with midazolam 0.3mg/kg, 30-45 minutes before the procedure. The following information including age, gender, weight, ASA status, time of last oral intake, preoperative fasting duration, surgical procedure, any history of POV with prior surgery and history of POV in parents or siblings will also be noted preoperatively. Patients at high risk of POV will not be included in the study as prophylactic antiemetic is needed to be given to such patients. Once the patient is taken into the operation room, standard ASA monitoring including electrocardiography, non-invasive blood pressure and pulse oximetry will be applied. Mode of induction will be inhalational with 8% sevoflurane and 100% oxygen or intravenous with propofol 2.5-3mg/kg. Airway will be secured with a supraglottic device appropriate to the weight of the patient. Patient will be positioned for caudal block which will be performed using small gauge butterfly cannula using 0.25% ropivacaine in a dosage of 1ml/kg body weight with a maximum safe dose of 3mg/kg. Maintenance will be achieved with isoflurane in an oxygen and nitrous oxide mixture of 60% and 40% respectively. Minimum Alveolar Concentration (MAC) will be kept between 1.0-2 %. Patients receiving any opioids or antiemetic will be excluded from the study. Intraoperative details of fluids will be noted (total volume and type of fluid). After completion of surgery, supraglottic airway device will be removed deep or awake at the discretion of primary anesthetist and patient will be shifted to the recovery. In PACU and day care ward, child will be assessed for vomiting by recording the number of episode of vomiting and for pain using Wong Baker FACES pain scale.The time of breaking NPO and type of first feed will be noted. Patient will be followed postoperatively for a period of 12 hours for any episodes of vomiting and pain in PACU and on the daycare ward. The decision of breaking NPO will be based on the current practice of pediatric surgeons and will not be interfered with.

Criteria for discharge from the PACU will include full consciousness, adequate pain control determined using Wong Baker FACES pain scale (pain score of less than 4), no bleeding, stable vital signs, and no vomiting. These patients will be followed up initially till discharge from daycare ward. Later, the child will be followed up postoperatively on second day via phone call to the parents for the occurrence of any pain and vomiting and parental satisfaction with the anesthesia will also be asked. These results will be correlated with the length of fasting.