Propofol ou kétamine pour l'anesthésie du grand vieillard. Etude des effets hémodynamiques à l'induction

Abstract

The haemodynamic changes following anaesthesia for hip surgery in 16 very old ASA II or III patients (mean age 85.8±5 years) were studied. Patients were randomly assigned to two groups : group I 1 mg · kg −1 propofol, group II 1.5 mg · kg −1 ketamine. After injection, the patients were left spontaneously breathing oxygen, and were assisted when apneic. Haemodynamic measures with a Swan-Ganz catheter and thermodilution cardiac output calculator were made before and 1, 3, 5, 10 and 15 min after anaesthetic induction. The two groups were similar in age, weight and mean arterial pressure, but statistically different for some haemodynamic parameters (Ppa, Ppw, CI). In groupe I, arterial pressure fell significantly (−17%) in the first minute and continued to fall (−15%) until the 15 th min. Heart rate remained unchanged : right atrial and pulmonary pressures were not changed; cardiac index fell slightly and MV̇o 2 estimated by the triple product fell (−27%) as soon as propofol was infused. There was no clinical sign of cardiac failure. In group II, arterial pressure increased significantly, and heart rate decreased; pulmonary capillary wedge pressure increased (+93% after the 3 rd min) and cardiac index was unchanged. The ventricular function curve was shifted to the right, suggesting a decrease in inotropism. Systemic vascular resistances were steady. MV̇o 2 increased twofold, mainly due to the rise in pulmonary capillary wedge pressure. In conclusion, the cardiovascular state was maintained in the two groups, however with two opposite patterns : MV̇o 2 decreased with propofol, whilst its increase was important and long lasting with ketamine. Propofol appeared to be a valuable anaesthetic agent for old people when MV̇o 2 elevation may be dangerous.