[Change of sedation depth, oxygen consumption index and hemodynamics after withdrawal of midazolam sedation].

ABSTRACT

BACKGROUND: The change of oxygen consumption after withdrawal of sedation is controversial. We evaluated the changes of sedation depth, oxygen consumption and hemodynamics after withdrawal of midazolam sedation in the patients undergoing major abdominal surgery. METHODS: We evaluated 18 patients after major abdominal surgery. Midazolam was used for intravenous sedation after admission to the ICU. Midazolam was administered at a bolus dose of 0.1 mg kg(-1), followed by continuous infusion at 0.04 mg kg(-1) hr(-1), which was adjusted every 2 hrs to achieve a desired level of sedation of 4 on Ramsay sedation scale (RSS). After about 14 hours of sedation, we stopped the infusion of midazolam. From that time, we measured systolic and mean arterial pressure, heart rate, minute volume and oxygen consumption, and evaluated RSS every 5 minutes for 1 hour. We evaluated RSS as sedation depth, oxygen consumption index (V(O2)I) and rate pressure product (RPP=systolic arterial pressure x heart rate) as hemodynamic parameters. RESULTS: RSS significantly decreased gradually, but the other parameters including V(O2)I and RPP were unchanged. CONCLUSIONS: After withdrawal of midazolam sedation in the patients undergoing major abdominal surgery, the sedation depth became lighter, but V(O2)I and RPP were unchanged.