Induction of general anesthesia with tracheal intubation may cause hypertension and tachycardia with concomitant increase in plasam catecholamine concentration. These transient stress responses are undesirable, especially in patients with
cardiovascular
or intracrainal diseases. Many drugs(topical or i.v. lidocaine, inhalation anesthetics, opioids, adrenergic blockers, etc)are used in an attempt to blunt these potentially adverse hemodynamic responses.
This study was made to examine blunting effect of labetalol and fentanyl for hemodynamic changes after tracheal intubation.
Eighty patients, ASA physical status I orⅡ, scheduled for elective surgery were selected randomly. They were divided into four groups.
Group 1: Control(saline)(n=20)
Group 2: Labetalol 0.125mg/kg(n=20)
Group 3:Labetalol 0.25mg/kg(n=20)
Group 4: Fentanyl 3 μg/kg(n=20)
Study drugs were injected 3 minutes before induction with thiopental sodium. Patients were induced with thiopental sodium 5mg/kg and succinylcholine chloride 1 mg/kg i. v. in all groups. 5 minutes after injection of study drug, laryngoscopy was
initiated and performed tracheal intubation. After the completion of intubation, 50% nitrous oxide in oxygen and 1.5vol.% halothane was administed.
The blood pressure and heart rate were measured using automated noninvasive blood pressure device and E. C. G. monitoring for 10 minutes per 1 minute. Data were analyzed with Student's t-test within the group and unpaired t-test between the
groups.
P<0.05 was considered significant.
Labetalol or fentanyl pretreatment significantly blunted the increase in heart rate and rate pressure product caused by laryngoscopy and endotracheal intubation. But the increases of arterial blood pressure was blunted significantly in fentanyl
3μg/kg
group. Labetalol and fentanyl may offer an important role in patients in whom an increase in blood pressure, heart rate and/or rate pressure product should be avoided during the endotracheal intubation.
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