Abstract
The longterm effects of ketamine on haemodynamic parameters and exogenous catecholamine requirements were studied in twenty-five critically ill patients with catecholamine-dependent heart failure. Following sedation with midazolam (0.15±0.07 mg.kg–1.h–1) and sufentanil (0.88±0.33 μg.kg–1.h–1), patients with impaired left ventricular function (left ventricular ejection fraction area 30±7%) were randomly assigned to receive ketamine (2.5±0.9 mg.kg–1.h–1) and midazolam (Group A) or remained on sufentanil/midazolam (Group B). Haemodynamic measurements were performed throughout the first 24 hours after randomization. In group A cardiac index decreased by 21% (P=0.01), mean arterial pressure increased by 13% (P=0.01), mean pulmonary artery pressure by 14% (P=0.04), pulmonary capillary wedge pressure by 20% (P=0.03), and systemic vascular resistance index by 38% (P<0.001). No significant cardiovascular effects were observed in Group B. Neither group had significant changes of exogenous catecholamine requirement.
In conclusion, ketamine exhibits potential negative cardiovascular effects in patients with catecholamine-dependent heart failure. Therefore, ketamine should not be considered a first line drug for longterm sedation of patients with impaired left ventricular function.