Effect of Two Different Doses of Dexmedetomidine Infusion in Morbidly Obese Patients

The Effect of Two Different Doses of Dexmedetomidine Infusion on Oxygenation, Lung Mechanics, and Quality of Recovery in Morbidly Obese Patients: A Prospective Randomized Controlled Study

Compare the effects of two different doses of dexmedetomidine infusion on oxygenation as a primary outcome and on lung mechanics, quality of recovery and perioperative analgesia as secondary outcomes in morbidly obese patients with restrictive lung disease undergoing abdominal surgery.

Dexmedetomidine is a selective α2 receptor agonist and has sympatholytic, analgesic, anti-inflammatory and sedative properties. Dexmedetomidine decreased dead space and improved both lung compliance and oxygenation in chronic obstructive pulmonary disease (COPD) patients undergoing lung cancer surgery. The effects of dexmedetomidine on oxygenation and lung mechanics had been investigated in obstructive lung disease, but there are little information about its effect in morbidly obese patients with restrictive lung disease .

patients will receive a bolus dose of 1µg/kg dexmedetomidine15 minute after endotracheal intubation over 10 minutes followed by continuous infusion of 0.6 mic/kg/hour for one hour.

patients will receive a bolus dose of 1µg/kg dexmedetomidine 15 minute after endotracheal intubation over 10 minutes followed by continuous infusion of 0.3 mic/kg/hour for one hour.

Patients will receive comparable volume of normal saline (0.9%) 15 minute after endotracheal intubation.

Patients received a bolus dose of 1μg/kg Dexmedetomidine, 15 minutes after endotracheal intubation over 10 minutes followed by infusion of 0.6 μg/kg/hr for one hour.

Patients received a bolus dose of 1μg/kg Dexmedetomidine, 15 minutes after endotracheal intubation over 10 minutes followed by infusion of 0.3 μg/kg/hr for one hour.

Patients received over 10 minutes comparable volume of normal saline (0.9%) 15 min after endotracheal intubation followed by infusion.

Intraoperative oxygenation was assessed by P/F ratio (Arterial oxygen tension/fraction of inspired oxygen) at baseline and the end of drug infusion.

Assessment of post-operative pain by The 11-point numeric scale ranges from '0' representing one pain extreme (e.g. "no pain") to '10' representing the other pain extreme

Physiological dead space was calculated by Hardman and Aitkenhead equation: (dead space to tidal volume) = 1.14(PaCO2 -EtCO2)/PaCO2- 0.005 dead space (%) = dead space by end of infusion - dead space at the base line / dead space by the end of drug infusion %

The Quality of recovery score scale provides a score ranging from 0 to 150, with a high score indicating a good quality of recovery

Inclusion Criteria: Body Mass Index above 40 kg/m2 with restrictive lung disease((forced vital capacity) <70% in pre-operative pulmonary function tests), of American Society of anesthesiologists (ASA) physical status II and III. Aged 18-50 years. Scheduled for abdominal surgery. Exclusion Criteria: Patients with Forced expiratory volume1/forced vital capacity<7. Uncontrolled cardiac, respiratory, hepatic or renal diseases. Allergy to the study drug

The data will be available upon a reasonable request from the corresponding author after the end of study for one year.