Purpose: Urapidil is an antihypertensive drug with actions of α1-receptor blockade and 5-HT1A (5-hydroxytryptamine) receptor stimulation. Although many agents have been used to attenuate the cardiovascular response to endotracheal intubation, few of them are related to urapidil. This study was done to evaluate the effects of urapidil on reducing the cardiovascular response to intubation.
Methods: In this randomized, double-blind, placebo-controlled study, 30 ASA I-II adult surgical patients without cardiovascular disease were divided into two groups of 15 each, receiving either an i.v. bolus of 0.6 mg·kg-1 urapidil 5 min before intubation or an equivalent volume of saline as control. The heart rate and the systolic and diastolic blood pressure were determined intermittently for 5 min before and 10 min after intubation. The mean blood pressure, product of systolic blood pressure and heart rate, and coefficient of variation (CV) of these variables around intubation were calculated.
Results: Urapidil had no effects on the heart rate (P>0.05), could effectively attenuate the increases in the diastolic and mean arterial pressures (P<0.05) caused by intubation, but had a weak effect on the systolic pressure (P>0.05) and its product with heart rate. In addition, the CV of the diastolic pressure and mean arterial pressure was greater (P<0.05) in the urapidil group than in the control group, which meant that the induction procedure with urapidil was not more stable than that when saline was used as placebo.
Conclusion: The effects of urapidil on reducing the cardiovascular response to intubation are mild when uradipil is used 5 min before intubation. As urapidil mainly decreases diastolic blood pressure, an important determinant of cardiac blood supply, and it makes systolic, diastolic, and mean blood pressure fluctuate strongly during induction, we should be alert about its latent detrimental effect on patients, especially those with ischemic heart disease.
Keywords: Cardiovascular response; Endotracheal intubation; Urapidil.