Low dose fentanyl attenuates hypertension but not tachycardia during laryngoscopy and tracheal intubation in a three arm study

Background: Tracheal intubation may induce; hypertension, tachycardia, and/or arrhythmia. Fentanyl is a frequently used opioid that joins with hypnotic agents to diminish hemodynamic responses to tracheal intubation. Furthermore, lidocaine has a suppressive effect on the circulatory responses in patients undergoing laryngoscopy and tracheal intubation. However, intravenous lignocaine has shown variable results and large doses of fentanyl causes hypotension and cough. We compared the effectiveness of intravenous lignocaine 1.5 mg/kg bolus and intravenous fentanyl 2 mcg/kg bolus in attenuating the sympathetic response to laryngoscopy and tracheal intubation. Materials and methods: One hundred and fifty ASA physical status I or II patients undergoing elective, non-cardiac procedures were randomized, to one of the three treatments such as either normal saline or lignocaine 2 mg/kg or fentanyl 2 mcg/kg. Intubation was carried out 3 minutes after administration of these study drugs. Patients received Midazolam before induction, and Thiopental, Rocuronium during anesthesia. The heart rate, blood pressure and SPO2 were recorded a day before (B), before intubation (0) at 1 2 3 4-5 minutes after induction. Results: Tachycardia (HR>100 beats/min) after intubation was statistically similar across 85% (17/20), 75% (15/20) and 55% (11/20) saline, lignocaine, and fentanyl respectively (p>0.05). Hypertension (SBP > 180 mmHg) was seen in 80% (16/20), 70% (14/20) and 40% (8/20) with saline, lignocaine and fentanyl respectively. The incidence of hypertension with fentanyl was significantly (p<0.05) lower than saline; however, such a meaning was not observed with lignocaine. Conclusion: Low dose of fentanyl prevented hypertension but not tachycardia as compared to normal saline; on the other hand, lignocaine did not attenuate cardiovascular responses during laryngoscopy and tracheal intubation.