To Evaluate and Compare the Efficacy of Propofol, Etomidate as Induction Agent in Maintaining Haemodynamic Stability in Elective Surgery Under General Anaesthesia

Hemodynamic stability at the time of induction of anaesthesia and during surgery has been major concern for the anaesthetist of both ancient and modern era’s . Induction agent’s causes vasodilatation, myoclonic seizures, nausea and vomiting and attenuation of axis thereby decreasing blood pressure. The aim and objective of this study is to evaluate the hemodynamic effect of etomidate and propofol and as induction agents in elective surgeries under general anaesthesia. To observe any postoperative adverse effects such To observe any postoperative adverse effects such as nausea , vomiting or seizures with propofol and etomidate as induction agent. INTRODUCTION Hemodynamic stability at the time of induction of anaesthesia and during surgery has been a major concern for the anaesthetist of both Ancient and modern eras. The maintenance of hemodynamic stability during induction of anaesthesia is dependent on both basal tone of the autonomic nervous system and also importantly influenced by baroreceptor reflex regulation of autonomic outflow influencing cardiac function and peripheral vascular resistance. Direct laryngoscopy and intubation produces marked circulatory effects known as pressor response, characterised by a sudden increase in heart rate and altered rhythm. Pressor response to laryngoscopy and intubation is documented fact in patients, under a variety of anaesthetic techniques. (2-3) The effects of laryngoscopes and intubation on the cardiovascular system were noted early that the cardiac reflex could originate in the trachea, larynx and bronchi. These reflexes were named vasovagal since both the afferent and efferent paths of the reflex were assumed to the vagus nerve, however In 1990 concluded that these changes could be attributed to the stimulation of cardio accelerator nerves implying an increase in the cardiac sympathetic tone rather than vagal stimulation . This response is due to an increase in cardiac output rather than an increase in systemic vascular resistance. (4) It is proposed that the mechanism of hemodynamic and catecholamine response to or tracheal intubation is that of somato-visceral reflex. Direct laryngoscopy activates proprioceptors at the base of the tongue which leads to hypertension, tachycardia and other International Journal of Scientific and Research Publications, Volume 10, Issue 3, March 2020 33 ISSN 2250-3153 http://dx.doi. org/10.29322/IJSRP.10. 03.2020. p9906 www.ijsrp. org arrhythmia in proportion of magnitude of stimulus. Subsequent intubation stimulates the receptors in larynx and trachea with enhancement of hemodynamic and epinephrine response (5) The mean increase in arterial pressure due to laryngoscopy and intubation may be upto 20-25 mmHg. This peak response occurs approximately 30-35 sec after laryngoscopy. These cardiovascular changes due to direct laryngoscopy and intubation are transient, variable and unpredictable and usually well tolerated by healthy individuals, however these changes may be fatal in patients with hypertension, coronary artery disease or raised intracranial tensions. It was also demonstrated that there is an increase in concentration of catecholamines like adrenaline and non adrenaline in response to the stimulus of laryngoscopy and intubation (6) Wide range of intravenous induction agents of anaesthesia is now available. Thiopentone, propofol, etomidate, ketamine are used for induction to lower the stress response to laryngoscopy and intubation and to maintain better hemodynamic stability at the time of induction and during surgery. Induction agents cause vasodilatation, myoclonic seizures, nausea, vomiting and attenuation of Autonomic Nervous System thereby decreasing blood pressure. Each intravenous anaesthetic induction agent affects hemodynamic changes differently. Thiopental is a commonly used induction agent. In this study, we aim to evaluate the hemodynamic effects of propofol and etomidate in order to find the better hemodynamic stability during induction, laryngoscopy, intubation and during surgery under general anaesthesia in elective surgeries. MATERIAL AND METHODS This randomized double blind clinical study was conducted in the department of anaesthesia National institute of medical sciences Rajasthan jaipur, after approval from Institutional Ethical Committee ,on 60 patients aged between 18 to 60 years of either sex , ASA physical status I and II undergoing elective surgery lasting for approximately 2 hrs under general anaesthesia. Written informed consent was taken from all patients. The patients were randomly divided into three groups. Randomization was done by computer generated random numbers tables. Group I induction with inj.propofol (2mg/kg IV) Group II induction with inj.etomidate (0.3mg/kg IV) Patient having following criteria were excluded from the study 1) Cardiac, hepatic and renal disease 2) Respiratory diseases 3) Known hypertensive 4) Known diabetic 5) Epilepsy 6) Pregnant patients 7) Known case of difficult airway (MP grade III and IV) Baseline heart rate (preoperative) systolic blood pressure (SBP) diastolic blood pressure (DBP) mean blood pressure (MBP) and oxygen saturation (SPO2) and end tidal carbon dioxide (ETCO2) were noted. The patients were kept nil per oral for 8 hours prior to the surgery. All patients were premedicated with tab.alprazolam 0.25mg; tab Ranitidine 150mg at night before surgery and in the morning. All patients received inj.glycopyrolate 0.2mg i.v. In preoperative ward prior to the surgery. On arrival at operation theatre standard anaesthesia monitors including pulse oxymetry, electrocardiogram, non invasive blood pressure (NIBP) was attached and hemodynamic parameters were recorded. A 18 G intravenous cannula was secured and ringer lactate infusion was started. Inj midazolam 0.025 mg/kg iv and inj. Nalbuphine 0.1mg/kg was given 2 minutes before International Journal of Scientific and Research Publications, Volume 10, Issue 3, March 2020 34 ISSN 2250-3153 http://dx.doi. org/10.29322/IJSRP.10. 03.2020. p9906 www.ijsrp. org induction. Group I received inj. Propofol 2mg/kg iv and group II etomidate 0.3mg/kg iv.All study drugs were prepared by an anaesthesiologist who was blinded to the details of the study. Volume of medication and speed of injection were equal in all three groups. After induction of anesthesia, hemodynamic variables were recorded. Inj rocoronium1-2mg/mg given. Laryngoscopy and endotracheal intubation was done by experienced anesthesiologist. Duration of laryngoscopy was kept less than 10 seconds. Trachea was intubated with adequate size of endotracheal tube. Proper placement of ETT was confirmed by capnography and bilateral auscultation of chest. Following successful placement of ET tube anesthesia was maintained by isoflurane 1-1.5% and equal mixture of oxygen-nitrous oxide (4 L/min) along with intermittent bolus of rocuronium as required throughout the surgery. Heart rate, systolic blood pressure, diastolic blood pressure ,mean arterial blood pressure and oxygen saturation were continuously monitored and recorded before induction and after induction at 1 minute , 2 minute, 5 minutes ,10 minutes, 20 minutes,30 minutes,60 minute by the anaesthesiologist who is blinded to the study . OBSERVATIONS AND RESULTS This prospective randomized double blind study was carried out on 60 patients between the age group 18-60 years at MIMS, Rajasthan Jaipur to evaluate the hemodynamic effects of etomidate and propofol as induction agent in elective surgeries. Age distribution of patients in different groups(Table 1) Age(in years) N Group I (n-30) Group II (n-30) x p-value