Effect of Nalbuphine Versus Fentanyl on Hemdoynamic Effects of Laryngoscopy

Participants will undergo standard preoperative assessment and will receive oral alprazolam 0.5 mg the night before surgery. Intravenous access will be established in the recovery area. Upon arrival in the operating room, standard monitoring will be applied, including non-invasive blood pressure, pulse oximetry, electrocardiography, capnography, and temperature monitoring. Under aseptic conditions and local anesthesia, a central venous catheter will be inserted into the internal jugular vein and an arterial line into the radial artery.

Premedication with intravenous midazolam 0.01 mg/kg will be administered and baseline parameters recorded. An opioid analgesic (nalbuphine 0.2 mg/kg or fentanyl 3 µg/kg) will be given intravenously over 5 minutes prior to induction of anesthesia. General anesthesia will be induced with intravenous etomidate 0.3 mg/kg. After adequate sedation, atracurium 0.5 mg/kg will be administered to facilitate neuromuscular blockade, followed by bag-mask ventilation with 100% oxygen. Endotracheal intubation will then be performed under direct laryngoscopy, with confirmation of bilateral air entry and secure fixation of the tube.

Anesthesia will be maintained with 60% oxygen in air, sevoflurane (approximately 2 MAC), and a continuous atracurium infusion (5-12 µg/kg/min). Hemodynamic parameters including heart rate and arterial blood pressure will be continuously monitored during the peri-intubation and intraoperative period.

Inclusion criteria

• Weighing 40-70kg

• ASA III of either sex
• Undergoing cardiac surgery with CPB

Exclusion criteria

• History of Drug Allergy • Pre-existing Asthma • Renal or Hepatic dysfunction • Extreme obesity • Pregnant / lactating patients • Difficult intubation/prolonged intubation