Effect of Intravenous Paracetamol Combination With Caudal Ropivacaine on Quality of Postoperative Recovery in Pediatric Patients Undergoing Hypospadias Repair.A Randomized Controlled Trial.

After obtaining approval from Ethical Review Committee (ERC) of Aga Khan University Hospital Karachi (AKUH) and inform about the study to primary surgeon (who ever doing the surgical procedure on this time), informed written consent will be obtained from the parents of patients fulfilling the inclusion criteria schedule for surgical procedures on the day before surgery. Assent will be obtained from older children.

The patients will be assigned to one of the two groups by randomization through sealed opaque envelope technique. The envelopes will be prepared using a computer generated randomization table. Randomization envelopes will be used in consecutive order.

Patients will be allocated to either placebo group, who will not receive intravenous paracetamol, or group who will receive intravenous paracetamol.

All patient will be given general anesthesia as per standard of care. Anaesthesia will be standardized as follow. Anaesthesia will be induced by the inhalational route with application of facemask with 8% sevoflurane in 50% oxygen-nitrous oxide mixture. Airway will be managed by laryngeal mask airway (LMA) of appropriate size as recommended by manufacturer and anesthesia will be subsequently maintained with Minimum alveolar concentration 1-2% sevoflurane in 40% oxygen-nitrous mixture with spontaneous ventilation via LMA. Heart rate (HR), noninvasive blood pressure, core body temperature (oral/nasal probe), end-tidal carbon dioxide (ETCO2) and oxygen saturation by pulse oximetry (SpO2) will be monitored throughout.

After induction of anaesthesia, patients will be turned to lateral position and maximum safe dose of ropivacaine will be calculated (3mg/kg) and documented. After all aseptic measures, butterfly needle (size 23 gauge) will be inserted into the sacral hiatus. A total volume of 1 ml/kg of 0.25% ropivacaine solution will be injected in caudal space. The time of performing block will be noted. The success of caudal analgesia will be assessed by monitoring the parameters like heart rate (HR) and blood pressure (BP) in response to incision. In case of tachycardia (>20% from baseline) and hypertension (>20% from baseline), the concentration of sevoflurane will be adjusted. If tachycardia persists for more than 5 minutes despite increasing the sevoflurane concentration, rescue analgesia in the form of fentanyl 1mcg/kg will be administered.