Efficacy of nifedipine on cardio- vascular response during laryngoscopy and intubation

Background: The procedure of laryngoscopy and intubation is an integral part of modern day balanced anaesthesia. It is also the most delicate phase in general anaesthesia. It is performed for most major and some minor surgical procedures. The procedure of direct laryngoscopy and intubation is associated with significant haemodynamic changes such as increased heart rate, arterial pressure and dysarrhythmias in most patients (REID LC ct al 1940). Unfortunately these changes are often overlooked during anaesthesia as the anaesthesiologist may be much engaged in the intubation procedure and he has little opportunity to note any abnormal circulatory reactions. There exists an ongoing search for an ideal agents for attenuating cardiovascular responses to laryngoscopy and intubation. The aim of the present study was to see the effect of sublingual Nifedipine to reduce the adverse effects of intubation and laryngoscpy. We did a comparartive study in 40 normal healthy individuals undergoing surgery under general anaesthesia in our hospital. We divided patients in 2 groups (A & B) of 20 each. GROUP A: Patients received premedication only and formed the control group. GROUP B: Patients received 10mg. Nifedipine sublingual 20 minutes before induction. Baseline parameters were recorded in operation room e.g. pulse rate (PR), Blood Pressure – systolic (SBP) and diastolic (DBP),Mean Arterial Pressure (MAP),SPO2 % and E.C.G. The readings were recorded at the following intervals: -Just before giving drugs (baseline values, B.V) - After giving drugs (before induction, B.I ) - After induction, (A.I) - Just after laryngoscopy and intubation, (L&I) - Post intubation at 1st (I1), 3rd (I3), 5th (I5), 10th (I10), 15th (I15) and 30th (I30) minute’s interval. After completion of the study observations were tabulated, qualitatively and quantitatively analyzed using proper statistical methods. Results: Sublingual Nifedipine given 20 minutes before induction effectively attenuated the increases in blood pressure but caused significant tachycardia which was further exaggerated following laryngoscopy and intubation.