Comparison of esmolol versus diltiazem for attenuation of cardiovascular response during laryngoscopy and endotracheal intubation in patients undergoing elective craniotomy

Abstract

Background: Laryngoscopy and tracheal intubation may cause undesirable increases in BP and/or heart rate in anaesthetized patients. Present study was done to evaluate and compare esmolol and diltiazem for attenuation of pressor responses to direct laryngoscopy and endotracheal intubation in patients undergoing elective craniotomy. Materials & Methods:  The study was carried out in the department of Neuroanesthesiology & Critical Care at Bangur Institute of Neurosciences, IPGME&R, Kolkata, in 60 adult patients according to above stated selection criteria. They was randomly allocated into two groups – Group A (n=30) & Group B (n=30). Standard of heart rate, mean arterial pressure, SpO2, ECG was performed before induction of anaesthesia. Group A or esmolol group received esmolol 1mg/kg administered as a  i.v. bolus 2 minutes before direct laryngoscopy and intubation, and Group B (n=30) received inj.  diltiazem 0.2mg/kg i.v. bolus 60sec before direct laryngoscopy and intubation. After pre-oxygenation of at least 3 minutes, anaesthesia was induced with fentanyl 2µg/kg and inj. thiopentone sodium in increments of 50mg every 5 seconds until eye abolition of eyelash reflex. Inj. rocuronium 0.9mg/kg was administered by iv route to facilitate endotracheal intubation by appropriate sized non kinkable cuffed endotracheal tube. The tube was connected to capnometer and invasive intra-arterial pressure monitoring access was secured. Anaesthesia was maintained by N20/O2/Propofol and intermittent fentanyl injection. Muscle relaxation was maintained by continuous atracurium infusion. Hypoxia and hypercarbia was avoided throughout the procedure. Reversal from neuro-muscular blockade was done with inj neostigmine 0.05 mg/kg and inj glycopyrrolate 0.2 mg per mg of inj neostigmine. Extubation was done when the patient was fully awake, obeying commands, haemodynamically stable and after complete recovery from neuromuscular block. Thorough oro-pharyngeal suction was done before extubation. Results: In the present study esmolol given in group A in a dose of 1 mg /kg 120 seconds, prior to laryngoscopy and intubation caused a highly significant decline in SBP prior to laryngoscopy. There was a significant rise of mean SBP after intubation but at 2 and 5 minutes the SBP declined significantly. The MAP decreased highly significantly before laryngoscopy, that surged non-significantly at post intubation and finally settled down non-significantly at 2 and 5 minutes. Esmolol had caused a highly significant fall in HR at all the intervals of the study, except at 2 minutes past intubation when the decline was just significant. RPP had a highly significant decrease in its mean value at prior to laryngoscopy, post intubation, 2 and 5 minutes after intubation. The present study with diltiazem, administered as an intravenous bolus dose of 0.2mg /kg 60 seconds prior to laryngoscopy, demonstrated a highly significant fall in SBP just prior to laryngoscopy. There was an increase in SBP mean on intubation but to an insignicant value. Conclusion: With diltiazem, RPP after a highly significant decline prior to laryngoscopy surged to a significant extent on intubation. The RPP declined at 2 and 5 minutes of intubation, the fall at 2 minutes being highly significant.  On the other hand, with esmolol RPP had a highly significant decrease in its mean value at prior to laryngoscopy, post intubation, 2 and 5 minutes after intubation.