Comparison of Lidocaine Versus Nifedipine for Attenuation the Cardiovascular Response to Direct Laryngoscopy and Intubation during General Anesthesia

Abstract

Background: Laryngoscopy and Endo-tracheal intubation are gold standard for securing the airway and giving positive pressure ventilation. Drugs like Lidocaine, Fentanyl citrate and Nifedipine are used frequently to attenuate presser response to laryngoscopy and intubation, Single drug or technique is not satisfactory. Different methods of attenuation of response to laryngoscopy and intubation are still to be studied with new drugs tried every once a while. Aim: To compare the lidocaine and nifedipine effect on the cardiovascular response to direct laryngoscopy and intubation during general anesthesia Methods: Following the approval of the Institutional Review Board of AL jala Teaching hospital and written informed consent from patients undergoing elective surgery under general anesthesia, fifty patients between 18 and 60 years old, American Society of Anesthesiologist (ASA) Grades I and II, were randomized to one of the following groups, Group A: Lidocaine group 1.5 mg/kg IV bolus 3 minutes prior to laryngoscopy and intubation, Group B: Nifedipine group. 10 mg SL 15 minutes prior to induction. The induction protocol was standard for all patients. Intraoperative vitals were monitored using ECG, Pulse Oxymeter and NIBP. HR, SBP, DBP and MAP were recorded & RPP was calculated in all patients inside the operation theater just before induction (baseline), immediate after laryngoscopy and intubation, every 2 minutes after intubation during which no stimulus was given to patient for the next 10 minutes after laryngoscopy and intubation. Results: Patients' characteristics of age, gender and were comparable in the two groups. There was no significant difference between the groups regarding the type of the surgery. Statistically there was no significant difference (p=0.66) in the two groups in terms of ASA grading. No significant difference was observed between Lignocaine group and Nifedipine group values (P> 0.05), in any parameters at pre anaesthetic check-ups. the first significant change between the two groups , in which significant drop (p <0.05 ) in MAP occurred 4 minutes after intubation in group received Nifedipine sublingually, Once again , 6 minutes after intubation we recorded significant drop in SBP and MAP in Nifedipine group compared to Lidocaine group, No significant changes in parameters between two groups , 8and 10 minutes after intubation. The HR reached its maximum value immediately after intubation, after that the recording of HR became fluctuant in both groups. The percentage of rise in HR was less significant in Lidocaine group immediately after intubation and after that except for the reading 2 minutes, which was less significant in Nifedipine group. Both drugs failed to bring the HR to pre-operative value even after 10 minutes; the highest SBP was recorded at the pre-anaesthetic check-up. After that the SBP started to decline in both groups, this decline reached its maximum 4 minutes after intubation. After that the SBP started to gradually rise until 10 minutes without reaching the pre-anaesthetic basal value. The percentage of decline was more pronounced in Lidocaine group immediately and after 2 minutes of intubation and more pronounced in Nifedipine group after that, The highest DBP was recorded at the pre-anaesthetic check-up. After that the DBP started to decline in both groups, this decline reached its maximum 4 minutes after intubation. After that the DBP started to gradually rise until 10 minutes without reaching the pre-anaesthetic basal value. The percentage of decline was more pronounced in Lidocaine group immediately after intubation and more pronounced in Nifedipine group after that, The highest MAP was recorded at the pre-anaesthetic check-up. After that the MAP started to decline in both groups, this decline reached its maximum 4 minutes after intubation. After that the MAP started to gradually rise until 10 minutes without reaching the pre-anaesthetic basal value. The percentage of decline was more pronounced in Lidocaine group immediately after intubation and more pronounced in Nifedipine group after that. The Pressure Rare Product reached its maximum value immediately after intubation, the highest decrease in Pressure Rare Product occurred 4 minutes after intubation in both groups Conclusion: Both drugs in our study ( Lidocaine and Nifedipine ) has been shown to be effective in attenuating and preventing the increase in haemodynamic stress response to direct laryngoscopy and intubation during general anaesthesia in our patients. However, Nifedipine is more effective than Lidocaine in preventing the hypertensive response and attenuating the increase in RPP, and Lidocaine is more effective in attenuating the tachycardia response than Nifedipine. Recommendation: Based on the results of this study, it is recommended to consider the use of iv Lidocaine and sublingual Nifedipine to reduce the presser effect of laryngoscopy and intubation.