The Effects of a Combination of Fentanyl and Esmolol on Hemodynamic Responses after Endotracheal Intubation in Hypertensive Patients / 대한마취과학회지

BACKGROUND: To prevent hypertension and tachycardia after endotracheal intubation, esmolol and low-dose fentanyl have been used and it was reported that the combination of them was more effective than either in normotensive patients. However there have been few studies in this regard using hypertensive patients. Therefore, the author evaluated the effects of a combination of esmolol and low-dose fentanyl on hemodynamic responses after laryngoscopy and endotracheal intubation in hypertensive patients. METHODS: Thirty hypertensive patients were premedicated with midazolam and glycopyrrolate. Fentanyl 2 microgram/kg and esmolol 1 mg/kg were injected before induction of anesthesia. Thiopental sodium 3 5 mg/kg and succinylcholine 1 mg/kg were used for the induction of anesthesia. Endotracheal intubation was performed at 5 minutes after fentanyl injection. Thereafter 50% nitrous oxide in oxygen and 2 vol% enflurane were inhaled. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP) and heart rate (HR) were measured before fentanyl injection (base), before intubation, and at 1, 3 and 5 minutes after intubation. RESULTS: At 1 minute after intubation, SBP and MAP did not change significantly, but DBP increased slightly compared to base (P 170 mmHg) developed in 2 patients at 1 minute after intubation, and hypotension (SBP 100 bpm) developed in 2 patents at 1 minute after intubation and bradycardia (HR< 50 bpm) in 1 patient at 5 minutes after intubation. CONCLUSIONS: In treated hypertensive patients, the use of a combination of fentanyl 2 microgram/kg and esmolol 1 mg/kg is a useful method to attenuate hypertension and tachycardia after endotracheal intubation.

ED95 of Esmolol for Protection of Tachycardia and Systolic Hypertension by Endotracheal Intubation in Anesthetic Induction with Enflurane, Nitrous Oxide, Thiopental and Fentanyl / 대한마취과학회지

BACKGROUND: Esmolol has been used combined with small dose of fentanyl to prevent tachycardia and hypertension induced by tracheal intubation, but there has been few studies about the appropriate doses of esmolol when used combined with fentanyl. METHODS: According to esmolol dose, 140 patients were randomly allocated to 7 groups of 20 patients. After 2 microgram/kg of fentanyl, 4 mg/kg of thiopental and 0.12 mg/kg of vecuronium were intravenously administered, mask ventilation for 3 minutes with enflurane, nitrous oxide and oxygen was followed. Then one of the doses of esmolol, 0, 0.2, 0.3, 0.45, 0.6, 0.8 or 1.0 mg/kg was administered. Ninty seconds later, tracheal intubation by direct laryngoscopy was performed. After then heart rate was monitored continuously and blood pressure was measured 5 times with 1 minute interval. The highest heart rate and systolic blood pressure were recorded. We calculated the doses of esmolol which reduce the incidence of tachycardia (increased above 100 bpm or by more than 40% of preinduction level) and systolic hypertension (increased above 170 mmHg or by more than 40% of preinduction level) below 5% respectively. RESULTS: The ED95 of esmolol for prevention of tachycardia induced by tracheal intubation was 0.56 mg/kg (95% CI: 0.44-0.81 mg/kg). But the incidence of systolic hypertension was so low even without esmolol injection that the esmolol dose was not significant factor. CONCLUSIONS: In anesthetic induction and tracheal intubation with enflurane, nitrous oxide, thiopental, vecuronium, and fentanyl 2 microgram/kg, esmolol 0.56 mg/kg was ED95 of preventing tachycardia. But the incidence of systolic hypertension was acceptably low even without esmolol injection.