The aim of this study is to compare the efficacy of oral melatonin versus nebulized dexmedetomidine in attenuating the hemodynamic response to direct laryngoscopy and endotracheal intubation in controlled hypertensive patients prepared for general anesthesia
Laryngoscopy and endotracheal intubation are associated with sympathetic stimulation and induce hemodynamic changes with consequent increase in heart rate (HR) and blood pressure (BP) which may lead to myocardial infarction, cardiac arrhythmias, cardiac failure and cerebrovascular accidents in patients with underlying cardiovascular or cerebrovascular diseases. Dexmedetomidine is a centrally acting α-2 adrenergic agonist with sedative, hypnotic, analgesic, anxiolytic, anti-sialagogue, antinociceptive and sympatholytic action. Premedication with dexmedetomidine through intravenous, intramuscular and intranasal route has been shown to effectively attenuate hemodynamic response to laryngoscopy and endotracheal intubation. Nebulization provides an alternative route of dexmedetomidine premedication with high bioavailability through both nasal (65%) and oral mucosa (82%) and avoids a venipuncture as a prerequisite. Recent studies have shown nebulization as a novel route of dexmedetomidine administration for attenuation of hemodynamic response to endotracheal intubation. Melatonin is a natural substance produced mainly in the pineal gland of all mammals and vertebrates. It is rapidly distributed and eliminated after intravenous administration. After oral administration, plasma concentration peaks after 60 min and is then eliminated. It exerts its hypnotic effects through the activation of the Melatonin receptors type I and II (MT1, MT2). It has shown potent analgesic effects in a dose dependent manner in experimental studies. It may induce relaxation of the arterial wall smooth muscle by increasing nitric oxide levels. Therefore, premedication with sublingual/oral Melatonin is associated with pre-operative anxiolysis and sedation without impairment of orientation, psychomotor skills, or impact on quality of recovery, moreover, it attenuates the hemodynamic stress response to laryngoscopy and tracheal intubation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Nebulized Dexmedetomidine (1μg/kg)
Oral Melatonin tablet (5mg)
Tanta University Hospital
Tanta, El-Gharbia Govenorate, Egypt
Change in Heart Rate (HR)
Heart Rate will be assessed using pulse oximeter in pre-operative room (baseline), before the induction of anesthesia, immediately before laryngescopy or intubation, 1 minute after induction, 3 minutes after induction, 5 minutes after induction, every 30 minutes till the end of operation.
Time frame: Till the end of surgery (up to 2 hours)
Change in Systolic and Diastolic blood pressure
Systolic and diastolic blood pressure will be recorded in pre-operative room (baseline), before the induction of anesthesia, immediately before laryngescopy or intubation, 1 minute after induction, 3 minutes after induction, 5 minutes after induction, every 30 minutes till the end of operation.
Time frame: Till the end of surgery (up to 2 hours)
Sedation levels using Ramsay Sedation Scale
Sedation levels will be assessed using Ramsay Sedation Scale (1, Anxious and agitated, restless, or both; 2, Cooperative, oriented, and calm; 3 Responsive to commands only; 4 Exhibiting brisk response to light glabellar tap or loud auditory stimulus; 5, Exhibiting a sluggish response to light glabellar tap or loud auditory stimulus; 6, Unresponsive) before administration of the study drugs, before induction of anesthesia (60 minutes after drug taken), every 30 minutes post operative till 2 hours after surgery.
Time frame: Till 2 hours after the surgery
Intraoperative requirement of fentanyl
Additional fentanyl bolus dosages of 1 µg/kg IV will be administered if heart rate or mean arterial blood pressure elevated more than 20% of the baseline (after exclusion of other causes than pain).
Time frame: Intraoperatively
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Masking
DOUBLE
Enrollment
70