A Comparison Of Intrathecal Ketamine Versus Intravenous Dexamethasone For Postoperative Analgesia In Parturients Undergoing Spinal Anaesthesia For Cesarean Section: A Randomised Trial

Caesarean delivery is associated with postoperative pain that may influence recovery, psychological maternal well-being, and breastfeeding Multimodal analgesic regimen including an intrathecal long-acting opioid, non-steroidal anti-inflammatory drugs, and acetaminophen has been suggested to effectively control postoperative pain after caesarean delivery Intravenous dexamethasone is recommended in elective caesarean delivery to decrease postoperative pain. Several systematic reviews and meta-analyses have examined the efficacy of dexamethasone after caesarean delivery and reported decreased postoperative pain and prolonged time to first analgesia In the same context, a meta-analysis of randomized controlled trials in humans suggests that there may be a benefit to using intrathecal ketamine as an adjunct to bupivacaine to improve postoperative pain after cesarean section . The mechanisms of action of intrathecal ketamine are incompletely understood. One study reports that ketamine's high lipophilicity allows for rapid diffusion into the venous system, namely through the azygos vein.

The following parameters will be monitored intraoperatively every 5 min:

• HR, SBP, DBP, and MAP and SpO2 and documented every 15 min. till the end of surgery.
• Any hemodynamic response to skin incision and to subsequent surgical steps will be documented.
• For maintaining HR or systolic in range of more or less than 20% of baseline intraoperatively, ephedrine and intravenous fluids will be used . No other analgesic will be given intraoperatively.
• primperan 0.1 mg/kg will be given at the end of the procedure to all patients.
• All patients will receive 20 iu of oxytocin more till 40 iu or any ueterotonic drugs ( papal,methylergometrine) if needed .
• Postoperative pain will be assessed using an 11-point (0=no pain and 10=worst pain) numeric rating scale (NRS). NRS for pain at rest and when coughing will be assessed serially at 1, 2, 4, 8, 16 and 24 h after surgery. The assessor and the patients will be unaware of the type of intervention received.
• Time for first analgesic request and NRS at first analgesic request will be recorded. The duration of analgesia will be evaluated as the time from block administration to the time at which patient complained of pain or NRS ≥4 on assessment at serial intervals and nalurphine will be used as rescue analgesia . Total doses of analgesics required in the first 24 h will be recorded.
• The presence of postoperative nausea and vomiting during the first 24 h will be recorded. Postoperative nausea or vomiting will be treated with 0.1 mg/kg of ondansetron. If the patient did not respond to ondansetron, then metoclopramide 10 mg will be given IV. Occurrence of any complications such as sedation ,nystagmus ,dizziness will be assessed