Clinical recovery and psychomotor function after brief anesthesia with propofol or thiopental.

Propofol, the new intravenous anesthetic agent, is generally used in outpatient anesthesia with expectations of fast recovery. We assessed recovery from anesthesia in a double-blind, crossover, controlled manner in 12 healthy volunteers using clinical tests during the first hour and several psychomotor tests 0.5, 1, 3, 5, and 7 h after brief anesthesia with propofol (2.5 mg/kg and 1.0 mg/kg 3 min later) or thiopental (5.0 mg/kg and 2.0 mg/kg 3 min later). Subjects were able to respond to command, sit, and stand steadily significantly faster (P less than 0.05) after propofol (time until standing steadily 33 +/- 7 min; mean +/- SD) when compared to thiopental anesthesia (time until standing steadily 62 +/- 29 min; mean +/- SD). Psychomotor performance remained significantly worse (P less than 0.05 to P less than 0.001) compared to control for 1 h after propofol and for 5 h after thiopental anesthesia. We conclude that the rapid and complete recovery makes propofol a suitable anesthetic for patients undergoing brief ambulatory surgery.

Sedation and recovery of psychomotor function after intravenous administration of various doses of midazolam and diazepam.

A placebo-controlled, double-blind, crossover trial in 11 healthy male volunteers compared clinical sedation and psychomotor function after intravenous injection of midazolam (0.05, 0.1, or 0.15 mg/kg), diazepam (0.15 or 0.3 mg/kg), or placebo (saline). The depth of sedation was estimated at 5-10-min intervals during the first hour after injection. A comprehensive battery of psychomotor tests was used to collect objective data of psychomotor performance before drug injection and 1, 3, 5, and 7 h after injection. Midazolam (0.15 mg/kg) produced the highest scores of sedation and most impairment of psychomotor performance. In most tests, the maximal psychomotor effects seen after 0.3 mg/kg of diazepam did not reach those of 0.1 mg/kg of midazolam. Although the strongest psychomotor effects were induced by midazolam, these effects disappeared sooner than those of diazepam. By 5 h after injection, 0.3 mg/kg of diazepam showed the highest scores of psychomotor impairment. The authors conclude that at least four times as much diazepam as midazolam is needed to produce equally severe psychomotor impairment. That the residual effects of midazolam terminate sooner than those of diazepam probably accounts for the occasional underestimation of the potency of midazolam in clinical practice.

Evaluation of a new computerized psychomotor test battery: effects of alcohol.

In order to better evaluate the effects of centrally active drugs, a new computer based set of psychomotor tests was developed. Compared to the older apparati, the new set is very flexible and easy to operate allowing the measurement of hand/eye coordination, attention and several types of reaction skills. To evaluate the sensitivity and usefulness of the new tests, the effects of alcohol (oral doses of 0.5 g/kg and 1.0 g/kg) were studied in twelve healthy volunteers. The peak blood alcohol concentration after the larger dose was 0.86 g/l, and the effects were clearly seen with all new tests. The smaller dose of alcohol gave 0.33 g 1 peak blood alcohol concentration and it impaired significantly only coordination at 1 hr after drinking. The results suggest that the new tests are at least as sensitive and reliable as older psychomotor tests detecting the effects of central depressant agents. The advantage of the new tests is that they are easy to operate and easy to modify without any specific programming skills. Because they can be used with a computer which is easy to transport, these tests are suitable for use in clinical areas to conduct studies with patients.