Changes in Hemodynamics and Plasma Catecholamine Levels following Midazolam Premedication

Chon, Jin Young; Choi, Jeong Hwan; Chae, In; Kang, Yu Jin; Song, Ho Geong; Lee, Sung Kyun

Abstract

The present study atternpted. to expiore the new benzodiazepine, midazolam, which is water-soluble, shorter-acting, more potent, and less irritating to inject than diazepam, and which has been used as premedication before induction of anesthesia in various elective surgeries. Forty patients (aged 20 to 50 and in ASA class I or II ) about to undergo simple elective surgery under general anesthesia entered the study. The patients were divided into the study group (n=20) that recieved 0.07 mg/Kg i.m midazolan premedication and the control group (n= 20) that recieved normal saline as sham premedication. The changes in the values of various hemodynamic parameters, i.e., heart rate and systolic, diastolic, mean arterial pressures, were monitored first before tracheal intubation, then at the time of intubation and 5, 10 and 30 minutes after intubation. The concentrations of plasma catecholamines i.e., epinephrine and norepinephrine, were measured before intubation and 5, 30 minutes after intubation. Systolic pressure and plasma epinephrine concentration before induction was significantly low in the study compared with the controls. At the time of intubation, sytolic, diastolic & mean arterial pressures were significantly low in the study group compared with the controls. Heart rates measured at 10 and 30 minutes postintubation were significantly low at 30 minutes postintubation in the study group compared with the controls as was plasma epinephrine levels at each instance of its measurement. In conclusion, midazolam-premedicated patients appear to maintain stable hemodynamies and plasma catecholamine levels. Our findings support that midazolam premedication effectively reduces stress response during induction period making it suitable induction for elective surgery.