Efficacy of esmolol administration at different time intervals in attenuating hemodynamic response to tracheal intubation.

Background: Laryngoscopy and endotracheal intubation are known to cause increase in both arterial blood pressure and heart rate. Several strategies have been evolved to blunt the haemodynamic response to tracheal intubation but each method has its own advantages and disadvantages. Esmolol, a cardio selective Beta -1 blocking drug, can alleviate some of these problems. Esmolol, when administered parenterally, exhibits rapid onset and a short duration of action due to its rapid clearance by red blood cell esterases. Hence we conducted the present study to evaluate the efficacy and optimum time of single bolus esmolol administration in attenuating hypertensive- tachycardiac response to laryngoscopy and tracheal intubation. Materials and Methods: The randomized double blind prospective study was conducted in 60 patients, in the age group of 20-40 years, of both sexes, belonging to American Society of Anaesthesiologists (ASA) physical status class I or II and scheduled for elective surgery requiring endotracheal intubation and general anaesthesia. The efficacy and optimum time of single bolus esmolol administration in attenuating hypertensive - tachycardiac response to laryngoscopy and tracheal intubation was evaluated. Patients in group I (n=20) received bolus administration of injection esmolol 1.5 mg/kg intravenously (iv) 90 seconds before intubation; in group II (n=20) three minutes before intubation and in group III (n=20) six minutes before intubation. Results: There was no clinical and statistically significant variation in heart rate in group I and II at different time intervals of the study period but in group III heart rate increased significantly one minute after tracheal intubation. (P<0.05) One minute after intubation, the increase in systolic, diastolic and mean blood pressure and rate pressure product was statistically significant in group I (P<0.01) and group III. (P<0.05) However, in group II increase in systolic blood pressure and rate pressure product was statistically not significant. (P>0.05) Conclusion: To conclude, single intravenous bolus dose of esmolol (1.5 mg/kg) is safe and more effective in attenuating haemodynamic response to laryngoscopy and tracheal intubation when administered three minutes prior to intubation.

Efficacy of fentanyl and esmolol in the prevention of haemodynamic response to laryngoscopy and endotracheal intubation

To compare the effectiveness of single bolus dose of esmolol or fentanyl in attenuating the haemodynamic responses during laryngoscopy and endotracheal intubation. Randomized, placebo controlled, double blind study. Department of Anaesthesia and Surgical Intensive Care Unit, Civil Hospital, Karachi, from December 1998 to November 1999. Sixty adult ASA-I and ASA-II patients undergoing elective surgery were included in the study. The patients were randomly divided into three groups i.e., A, B and C. Heart rate, systolic, diastolic and mean blood pressures were recorded as 0= baseline and after administration of study drug, laryngoscopy and endotracheal intubation and 10 minutes thereafter. Study agent was injected 30 seconds before the induction of anaesthesia. Group 'A' [control] received 10 ml saline, group 'B' and group 'C' received fentanyl 2 mg/kg and esmolol 2mg/kg respectively diluted to make a total volume of 10 ml in normal saline. Readings of heart rate, systolic, diastolic and mean arterial pressures were compared with baseline and among each group. The rise in heart rate was minimal in esmolol group and was statistically significant. Following intubation, blood pressure was increased in all groups but was least in group C. Bolus injection of fentanyl 2 mg/kg 2 minutes prior to laryngoscopy and intubation failed to protect against elevation of both the heart rate and systolic blood pressure, whereas esmolol at 2mg/kg provided consistent and reliable protection against the increase of heart rate but not arterial blood pressure

Medicolegal aspect of voice analysis in prolonged endotracheal intubation versus laryngeal mask airway

Voice print analysis has been utilized in many different situations. The present study was designed to compare the changes of voice analysis in the first 24 hours after insertion of laryngeal mask airway [LMA] with those produced by endotracheal intubation. By using spectrum analyzer, we measured the frequency and the intensity level before and after anaesthesia at different intervals up to 24 hours from full recovery. There were significant differences between LMA and endotracheal intubation in the 2 variables [frequency and intensity]. Also the result demonstrated that both LMA and endotracheal intubation affected the voice print, but LMA caused little vocal changes than tracheal intubation and versus 24 hours after full recovery. The study suggest that the voice print must not be taken except after 24 hours from general anaesthesia