Dex as Analgesic Adjuvant in OSA Patients

A Double Blinded Randomized Placebo Controlled Study Evaluating the Use of Intraoperative Dexmedetomidine in Reducing Postoperative Pain and Narcotic Requirement in Patients With Moderate to Severe OSA.

The purpose of this study is to assess whether intravenous peri-operative Dexmedetomidine reduces opioid requirements and or improves pain control after Uvulopalatopharyngoplasty (UPPP) in patients with obstructive sleep apnea (OSA).

BACKGROUND/STUDY SIGNIFICANCE Patients with OSA undergoing surgery have increased surgical risk compared to patients that do not have OSA . Perioperative medication such as benzodiazepines and opioids can decrease upper airway tone, inhibit central respiratory drive and inhibit upper airway reflexes. The supine position may also worsen the severity of the OSA. Additionally, this group of patients is more likely to have a higher incidence of complications, particularly post operative hypoxemia , difficult intubation , and complicated extubation course . Uvulopalatopharyngoplasty (UPPP) along with other tongue base procedures are commonly performed surgical procedures used to help alleviate the symptoms of obstructive sleep apnea (OSA). Postoperative management of oropharyngeal pain is challenging since narcotic administration may compromise respiratory status in OSA patients. The Anesthesiology and Otorhinolaryngology communities have begun to rethink acceptable narcotic use in OSA patients especially following the recent FDA announcement highlighting serious adverse effects related to codeine consumption in children who had undergone tonsillectomies. Dexmedetomidine (Precedex) is a sedative with minimal respiratory depression. Its mechanism is via alpha 2 agonism and has 8 times the affinity for the alpha 2 adrenoreceptor than clonidine. It has been shown to have sedative, analgesic, and anxiolytic effects. It produces a predictable and dose dependent decrease in heart rate and blood pressure. Dexmedetomidine undergoes extensive metabolism in the liver and is then eliminated as methyl and glucuronide conjugates mostly via the renal system. The pharmacokinetics are markedly affected by hepatic insufficiency .

This group will receive 1mcg/kg bolus of dexmedetomidine over 15 minutes after intubation followed by an infusion of dexmedetomidine at 0.5mcg/kg/hr until approximately 30 minutes before the end of surgery.

This group will receive a colorless, odorless liquid (i.e. normal saline) in order to resemble Dexmedetomidine.

Patient self-reported pain scores will be measured immediately after awakening post-op using the Numerical Pain Rating Scale and opioid requirements using morphine equivalents

Inclusion Criteria: Age 18 or older Patients scheduled for UPPP Patients with diagnosis of OSA via polysomnography American Society of Anesthesiology (ASA) classification 3 or lower Exclusion Criteria: Bradycardia as defined as resting heart rate <60 Beats per min (BPM) or symptomatic Any degree of heart block diagnosed by ECG Hypotension as defined as <20% from baseline or symptomatic Liver failure, (two fold rise in liver enzymes) Chronic Kidney Disease (CKD) III or greater History of allergy to opioids or dexmedetomidine ASA classification 4 or higher ICU or Step down admission Difficult airway as defined by previous history of difficult intubation or requiring a fiberoptic intubation.

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