SEDATION WITH PROPOFOL-FENTANYL IN CRITICALLY ILL PATIENTS

This study investigated the efficacy of a constant rate infusion of propofol and fentanyl in thirty patients requiring artificial ventilation for more than 24 h. A loading dose, which differed according to the patient's age, was administered over a 30 min period : 2.5 mg.kg-1 for patients less than 50 (G1) (n = 9), 2 mg.kg-1 for patients between 50 and 60 years old (G2) (n = 9), and 1.5 mg.kg-1 for patients over 60 (G3) (n = 12). This was followed by an infusion of 3 mg.kg-1.h-1 in G1 and G2, and 2 mg.kg-1.h-1 in G3. A 1-mu-g.kg-1.h-1 infusion of fentanyl was also given. The degree of sedation was assessed with the Ramsay scale before starting, after induction, and every four hours thereafter. When this proved to be insufficient, the dose of propofol was increased by 0.5 mg.kg-1.h-1 as well as that of fentanyl by 0.5-mu-g.kg-1.h-1. Heart rate, mean arterial blood pressure, blood propofol, creatinine, transaminase and lipid levels, and urine output were measured before, during, and after the infusion. The blood propofol level increased during the infusion, being correlated to the doses given (r = 0.64, p < 0.001). Sedation lasted 91.7 +/- 57.7 h. After stopping the infusion of propofol, mean recovery times were 7.5 +/- 5.9 min (G1), 11.4 +/- 11.4 min, and 14.4 +/- 13.5 min (G3) (p < 0.05). In this last group, 4 patients took more than 30 min to recover, even though blood propofol levels at the end of the infusion were lower than in the other group members. There was a significant decrease in heart rate in G3, as well as a significant fall in mean arterial blood pressure in G2 and G3, these not being correlated with propofol levels. Fluid loading was required in two patients in G2 and in six in G3 as a result of the fall in blood pressure. Urine volume did not change significantly. Cholesterol level increased in G1 and G3, as well as phospholipids in G1. Combined continuous infusions of propofol and fentanyl was a practical way of sedating, on the long-term, intensive care patients being mechanically ventilated. However, doses should be reduced in elderly patients so as to avoid delaying recovery, as well as the haemodynamic alterations.