Koduri Aparanji1, Manta Radhasundari2, Kommula Gopalakrishna3
Anaesthetic technique used for any surgery in adults comprises of induction with Intravenous (IV) anaesthetic drugs. When used as sole induction agent, drugs like propofol and thiopentone can produce adverse effects on cardiorespiratory system. When induction agent like propofol is combined with a sedative benzodiazepine, midazolam, synergism occurs between these two drugs causing reduction in total dose of primary drug like propofol, a technique called coinduction. Recent studies have shown that if a small dose of propofol itself also called predosing was given prior to induction of propofol, its dose requirement was reduced considerably with less adverse haemodynamic effects. This technique of induction of GA is called auto coinduction.
The aim of the study is to-
1. Find out the total dose of propofol required for IV induction when propofol is used as coinduction agent (auto coinduction) and when a small fixed dose of midazolam is used as coinduction agent (coinduction).
2. Study the effect on haemodynamic parameters and complications in both study groups.
MATERIALS AND METHODS
60 adult patients of either sex belonging to ASA grade I/II and posted for elective surgical procedures under general anaesthesia were randomly divided into two equal groups of 30 patients each. Group A- Auto coinduction group - These patients were given propofol 0.5 mg/kg body weight IV 2 minutes prior to induction with propofol. Group B- Midazolam coinduction group - These patients received midazolam 0.05 mg/kg body weight IV 2 minutes prior to induction with propofol. Total dose of propofol required in both study groups, haemodynamic parameters and complications were studied.
Patients of auto coinduction group required less dose of propofol for induction as compared to patients of midazolam coinduction group. No significant changes in pulse rate in both the groups. Insignificant rise in SBP, DBP and MAP following tracheal intubation in auto coinduction group as compared to that in midazolam coinduction group, which showed highly significant rise in the above parameters. The incidence of side effects in both the groups was low and comparable with no significant difference.
Auto coinduction with propofol for induction of anaesthesia is definitely superior to coinduction with midazolam