The use of ketamine and midazolam for analgesia and sedation in ventilated patients subject to obligatory treatment with catecholamines

This study was undertaken to compare two regimens for analgesic sedation in intensive care patients with exogenous catecholamine therapy, giving special regard to catecholamine demand and hemodynamic parameters. A total of 20 ventilated patients in a surgical intensive care unit were investigated in a prospectively randomized design. Exogenous catecholamine therapy with epinephrine and/or norepinephrine was started at systolic pressure (SAP) less than 85 mmHg or mean arterial pressure (MAP) less than 65 mmHg to maintain cardiovascular function. For analgesic sedation, patients received bolus injections of about 0.2 mg/h fentanyl and 2.5 mg/h midazolam (fentanyl group, n = 10) or an infusion of about 50 mg/h ketamine and 2.5 mg/h midazolam by syringe pump (ketamine group, n = 10). Before the investigation, all patients received fentanyl and midazolam. The study period was 48 h. During the course of the study, mean catecholamine dosage increased significantly in the fentanyl group from 12.1 to 16.3 micrograms/min (+33%, P = 0.003). In the ketamine group, mean catecholamine dosage decreased from 43.9 to 38 micrograms/min (-13%, P = 0.19). No significant differences in group levels or time course were observed with regard to MAP, heart rate, cardiac index, pulmonary capillary wedge pressure, and shunt volume. Levels of pulmonary artery pressure (PAP) were comparable in both groups (ketamine group 29 mmHg, fentanyl group 26 mmHg). In time course, PAP increased by about 5 mmHg in the ketamine group but not in the fentanyl group (P = 0.009). The average central venous pressure (CVP) was 12 mmHg in both groups. At the end of the investigation, CVP decreased in the fentanyl group and increased in the ketamine group (P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)