The Role of Preoperative Melatonin in Reducing the Inhaled Isoflurane Requirements in Open Nephrectomy

Study Overview
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Brief Summary
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Melatonin is a hormone that the pineal gland in the brain produces. Melatonin fulfills many functions in the body but it is mostly known for maintaining a circadian rhythm that is governed by the central circadian pacemaker (biological clock) in the suprachiasmatic nuclei in the hypothalamus. Melatonin works by attaching to receptors or nerve endings in the suprachiasmatic nucleus (SCN) in the hypothalamus. It binds to melatonin receptor 1 and melatonin receptor 2, commonly referred to as MT1 and MT2. People can take it as a natural or synthetic supplement to promote restful sleep. Melatonin showed promise for preventing shifts in sleep and wake times in people with jetlag and improving sleep in people with insomnia. It can also be used for headaches, cancer, and Alzheimer's disease. Melatonin can be used as an analgesic, sedative, and hypnotic drug that can distinguish it as an attractive alternative premedicant

Detailed Description
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A study that was done before in J Anaesth by Borazan H et al revealed that postoperative pain score in patients undergoing radical prostatectomy who received melatonin one hour before surgery as a premedication was significantly lower than the control group with a significant P-value( less than 0.05). The entropy is indicated for adult and pediatric patients older than 2 years intraoperatively for monitoring the electric state of the brain. In adult patients, state entropy and response entropy can be used as an aid in monitoring the effects of certain anaesthetic agents which will help the user to titrate the anaesthetic agent according to the individual needs of each patient. Furthermore, the use of entropy parameters may be associated with a reduction of anaesthetic use and faster emergence of anaesthesia. The entropy measurement is to be used as an adjunct to other physiological parameters. To the best of investigators knowledge, there is no study that examined the effect of melatonin on inhaled isoflurane requirements intraoperatively. So, in this study, the effect of melatonin will be assessed on intraoperative inhaled isoflurane requirements in patients undergoing open nephrectomy under general anaesthesia by using entropy

Official Title
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Effect of Preoperative Melatonin in Inhaled Anesthetic Consumption

Conditions
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Postoperative Pain

Intervention / Treatment
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* Drug: Melatonin 5 mg
* Drug: Sugar Coated Tablets


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing nephrectomy under general anesthesia aged from 20 to 60 years. ASA 1 or 2. BMI 25 to 30 Exclusion Criteria: Patients with uncontrolled hypertension. Patients presenting with (IHD, significant arrhythmias, heart failure). Allergy to melatonin. History of epileptic seizures, psychoactive medications, neurological disorders or trauma.

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: randomized controlled trial
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: melatonin group<br>Melatonin group (group M )will receive melatonin as a premedication 1 hour before surgery in a dose of 5 mg | Drug: Melatonin 5 mg<br>* study the effect of preoperative oral melatonin 5mg on isoflurane consumption and postoperative pain<br>|
| Placebo Comparator: control group<br>15 patients will be enrolled for open nephrectomy will receive sugar-coated tablets. Control group(group C) | Drug: Sugar Coated Tablets<br>* the control group patients will receive placebo tablets one hour before induction of anesthesia<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inhaled isoflurane requirement (volume%) to maintain entropy readings 40-60 | Inhaled Isoflurane requirement (volume %) will be titrated to maintain state entropy (SE) and response entropy (RE) readings 40-60 measured using GE carestation 650-crescent pulse anaesthesia machine(6). | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total morphine consumption over 24 hours postoperative |  | 24 hours | 
| Total intraoperative fentanyl consumption | The sum of fentanyl top up doses will be recorded | 2 hours |