Midazolam and Thiopentone as Co-induction

This study was undertaken to compare the induction characteristics of conventional thiopentone sodium, midazolam, and a combination of midazolam and thiopentone sodium as co-induction agent. Total one hundred and fifty patients of ASA grade I and II were divided into three groups in a double blind randomized study. Group-I received midazolam 0.25 mgkg-1 intravenously, group–II received thiopentone sodium 5 mgkg-1 intravenously and Group-III received midazolam 0.1 mg/kg-1 IV followed by thiopentone sodium 2.5 mg/kg-1 IV. Induction time was significantly prolonged with midazolam (group-II) compared to thiopentone sodium. The fall in systolic blood pressure (SBP) and diastolic blood pressure (DBP) was clinically insignificant in midazolam group. Induction with midazolam was not smooth and was associated with unwanted movement of limbs. Incidence of apnoea, pain, thrombophlebites were significantly less with midazolam. Co--induction with midazolam and thiopentone significantly reduced the induction time, unwanted movements of limbs, apnoea during induction and cardiovascular stability was also more in co-induction group than thiopenfone sodium group. Incidence and duration of drowsiness was also significantly lesser in coinduction group. These advantages signifies that combination of midazolan and thiopentone is better choice for induction of anaesthesia than the other conventional induction agent like individual midazolam or thiopentone. INTRODUCTION: Intra-venous anaesthetic agents are commonly used to induce anaesthesia, as induction is usually more rapid and smoother than inhalational agents. The induction agents available at present are not able to meet all properties of the ideal intravenous Original Article MIDAZOLAM AND THIOPENTONE AS CO-INDUCTION Md. Habibur Rahman1, Mahbub Hassan2, Md. Monirul Islam3 1. Associate Professor (C.C) Dept. of Anaesthesia, SBMC, Barisal 2. Professor (C.C) Dept. of Anaesthesia, Mymensingh Medical College. 3. Assistant Professor, BIRDEM, Medical College, Dhaka. anaesthetic agents1. Although many drugs have been used and trailed as IV induction agent but only a few drugs have stood the test of time. Of them thiopentone sodium, midazolam, ketamine and propofol are important Thiopentone sodium is the drug, widely accepted for IV induction from long 1935. The advantages of thiopentone include rapid onset, reliability and smoothness of induction. However, recovery with thiopentone is delayed and this is a major disadvantage particularly in out patients anaesthesia, where the patients are expected to ambulate soon after surgery. Ketamine has the advantage of good tissue tolerability and can be used either by intramuscular or intravenous routes. But it produces hypertonous, hypertension and emergence delirium and delayed recovery. Propofol is short acting with rapid onset and absence of excitatory effects. Beside these, there is a clear-headed recovery with this drug, which is very helpful for outpatient procedure. Pain on injection is a disadvantage. However, it is quite popular for induction and maintenance for short surgical procedures2. Midazolam hydrochloride an imidazole benzodiazepine derivative synthesized in 1976 and was introduced into anaesthesia practice in 1981 as a water-soluble benzodiazepine with short duration of action3. This drug is now gaining popularity as an induction agent because of its smooth induction and less cardiovascular and other side effects. Induction time with midazolam has been reported to vary from 30 second to 2.55 minutes in various studies4-5. Pre-medication reduces induction time. Midazolam acts synergistically with barbiturate, opioids, propofol. Induction dose of each of these agents can be lowered by 75% when it is combined Journal of BSA, Vol. 17, No. 1 & 2, 2004