Comparison of nalbuphine and dexmedetomidine for attenuation of haemodynamic response to laryngoscopy and intubation

Rationale: Laryngoscopy and endotracheal intubation is associated with haemodynamic changes which can be fatal to patients with hypertension, cardiac dysfunction, coronary artery disease and cerebrovascular disease. It increases heart rate and blood pressure which can precipitate arrhythmias, myocardial infarction, left ventricular failure, pulmonary oedema and cerebral haemorrhage. Various categories of drugs have been tried to attenuate this haemodynamic response but no ideal agent has been found till date. Recently dexmedetomidine and nalbuphine have been studied for attenuation of this haemodynamic response and have been found to be effective. None of the studies have compared these two drugs so this study is designed to compare nalbuphine and dexmedetomidine for attenuation of haemodynamic response to laryngoscopy and endotracheal intubation.

Purpose of study: To compare nalbuphine and dexmedetomidine in blunting intubation response and finding out the better drug with an eye on the side effects encountered.

Background of study: The haemodynamic changes occuring in response to laryngoscopy and intubation were first described in 1940 by Reid and Brace.Since then various categories of drugs have been studied to blunt this response in order to provide haemodynamic stability to patients specially cardiac patients.But they all have their own side effects hence the search for an ideal agent continues. Dexmedetomidine is a highly specific alpha-2 adrenergic agonist with sympatholytic properties.Numerous studies have found it effective in blunting intubation response. Nalbuphine is a agonist- antagonist opioid with cardiostable properties and it also has been found effective .

Aim: To compare the effects of nalbuphine and dexmedetomidine for attenuation of haemodynamic response to laryngoscopy and intubation.

Objectives:

1. To study change in       -           Heart rate (HR)

-           Systolic (SBP), diastolic (DBP) and mean (MAP) blood pressure

2. To study side effects and complications of both study drugs.

 Setting: Department of Anaesthesiology & Critical Care, UCMS & GTBH, Delhi.

 Study design: Randomised, Double Blind, Comparative study

Time frame: November 2016 to April 2018

 Sample size: 80 patients (40 patients in each group)

 Method: Group allocation is by computer-generated random number table, into two equal groups and concealed by sealed envelope.

·                     Group N (n=40): Patients will receive 0.2 µg/kg of nalbuphine diluted to 10 ml with 0.9% saline solution over a period of 10 minutes before induction of anaesthesia.

·                     Group D (n=40): Patients will receive 1 µg/kg of dexmedetomidine diluted to 10 ml with 0.9% saline solution over a period of 10 minutes before induction of anaesthesia.

 Standard general anaesthesia will be administered to all patients. Haemodynamic response to laryngoscopy and endotracheal intubation will be observed intraoperatively. Postoperatively patients will be observed for any side effects of the study drugs.

 Statistical analysis: Demographic quantitative data will be analysed by unpaired student t test and qualitative data by Chi square test. A p value of <0.05 will be considered significant. Haemodynamic parameters will be analysed using repeated measure of ANOVA followed by Tukey’s test at 5% level of significance. The side effects of two study drugs will be compared using Chi square/ Fisher exact test.

 Primary outcome measure: Change in heart rate (HR) and systolic blood pressure (SBP)

Secondary outcome measure:

·         Change in diastolic blood pressure (DBP) and mean arterial pressure (MAP).

·         Side effects of the two study drugs