Low-dose Propofol Research Articles

COMPARISON OF ARTERIAL AND ARTERIALIZED VENOUS CONCENTRATIONS OF PROPOFOL DURING INFUSION OF PROPOFOL

Seven patients received a series of low-dose propofol infusions designed to produce three successive pseudo-steady states of arterial blood concentration: 0.06, 0.17 and 0.43 micrograms ml-1. Arterial and arterialized venous blood samples were obtained simultaneously at the end of each infusion. The results indicate that 95% of the arterialized venous concentrations may be expected to lie within 1 +/- 43% of the corresponding arterial concentration, or -5 +/- 35% if one set of measurements with poor agreement between duplicate aliquots is omitted.

Does Propofol Have an Anti-Emetic Effect? A Prospective Study of the Anti-Emetic Effect of Propofol following Laparoscopy

In order to investigate the putative anti-emetic effect of propofol, 53 patients undergoing gynaecological laparoscopy were given a standard anaesthetic including induction with thiopentone. At the end of surgery, the patients received either a sub-anaesthetic does of propofol or an equivalent volume of normal saline. There was no difference in the incidence of nausea and vomiting between the propofol and control group. It is concluded that low-dose propofol does not have an anti-emetic effect.

Utilisation du propofol lors de 1 350 anesthésies pour sismothérapie

Propofol was used for 1 350 sessions of electro-convulsive therapy (ECT). After 0.5 mg of intravenous atropine, patients received 1 to 1.5 mg · kg −1 bolus of propofol over a period of 20 seconds or less. This was convenient for loss of the eye-lash reflex. A bolus of 15 to 20 mg suxamethonium was given, in non allergic patients, to prevent trauma from the seizure. The patient was hyperventilated with pure oxygen through a facial mask. The electric shock was delivered bitemporally after a dental protection had been inserted. For each patient, the following data were noted : sex, use of tricyclic antidepressant drugs, atopy, amount of administered propofol and the effective intensity of the electric shock. The 99 patients were given 16.27 ± 14 ECT sessions. Among them 26 took antidepressant drugs and 34 were atopic. There was no difference, except for weight, between the 25 men and 74 women. The mean dose of propofol was 1.37 ± 0.3 mg · kg −1. The dose decreased with increasing age. There was no statistical relationship between the amount of propofol and intensity of the electric shock required to set off a seizure. The use of antidepressant drugs, and atopy did not influence the required amount of propofol. Speed of injection seemed to be the determining factor for narcosis with low doses of propofol. Hyperoxia and hypocapnia induced by hyperventilating with pure oxygen seemed to facilitate occurrence and duration of seizures. Although propofol has been said to reduce the length of seizures, there is controversy concerning the ECT efficacy criteria. Propofol is generally well tolerated, has a low histamine release potential and its moderate hypotensive effect compensates for the haemodynamic changes due to the seizure.

HAEMODYNAMIC AND HEART RATE REFLEX RESPONSES TO PROPOFOL IN THE RABBIT: Comparison with Althesin

Propofol was administered to eight rabbits by constant i.v. infusion at 0.2, 0.4 and 0.6 mg kg-1 min-1 to produce light sedation. The lowest dose was compared with an infusion of Althesin 0.1 mg kg-1 min-1. The rabbits had been previously implanted with aortic and vena caval perivascular balloon cuffs to examine the baroreceptor-heart rate reflex and an aortic thermistor catheter for cardiac output (CO) measurements. A silastic catheter was placed in the pericardial sac so that the cardiac nerves could be blocked with local anaesthetic. Mean arterial pressure (MAP) was well maintained with all anaesthetic infusions. At the lower doses of propofol, CO increased by 20% (P less than 0.01) with a corresponding decrease in total peripheral resistance (TPR). However, CO and TPR were not changed significantly by Althesin. Both anaesthetics induced a similar tachycardia. Cardiac nerve blockade did not abolish the different CO and TPR responses observed for the two agents. A dose-related reduction in the range and gain of the baroreceptor-heart rate reflex was observed with propofol (P less than 0.05). The pattern of alteration of the reflex curve, however, differed between the two anaesthetics and the vagal efferent component was more resistant to blockade with propofol. The relative preservation of baroreceptor reflex responses, and the reduction in TPR by a reduction of resting constrictor tone, suggest propofol may have significant clinical advantages when used as a sedative infusion.