Midazolam, 0.2 mg/kg IV, for induction of intravenous versed anesthesia produces a greater decrease in systemic blood pressure and increase in heart rate than does diazepam, 0.5 mg/kg IV.
The haemodynamic effects of midazolam are significant in humans. In normal humans, midazolam, 0.15 mg/kg IV over 15 seconds, produces statistically significant reduction in systolic (5%) and diastolic (10%) blood pressure and increases the heart rate (1 8%).
Haemodynamic changes after midazolam 0.15—0.3 mg/kg IV, are similar to those seen with hypnotic doses of thiopental 3—4 mg/kg.
Despite the fall in systemic arterial pressure, the cardiac index was maintained in patients who received intravenous versed , making it suitable as part of an intravenous induction regimen in patients with ischemic heart disease, alternative to diazepam.
Cardiac output is not altered by midazolam, suggesting that blood pressure changes are due to decrease in systemic vascular resistance. In the presence of hypovolaemia, administration of midazolam results in enhanced blood pressure lowering effects similar to other IV induction intravenous versed agents.
Midazolam does not prevent blood pressure and heart rate responses evoked by intubation of the trachea. In fact, this stimulus may offset the blood pressure lowering effect of midazolam administered IV.
The effects on systemic blood pressure are directly related to the plasma concentration of midazolam. Intravenous versed 0.2 mg/kg IV administered statistically attenuates the increase in plasma catecholamines in response to hypotensive stress.
The cortisol and renin increases that occurred in response to the hypotension were not affected appreciably by midazolam Intravenous versed .