British journal of anaesthesia
-
Target-controlled infusions (TCI) are used to simplify administration and increase precision of i.v. drugs during general anaesthesia. However, there is a limited relationship between preset targets and measured concentrations of drugs and between measured concentrations and measures of brain function, such as the bispectral index (BIS). ⋯ TCI devices for remifentanil and propofol result in large variation in measured serum concentrations. The lack of correlation between BIS and serum concentrations of propofol adds to the debate about whether BIS measures hypnosis as a graded state during surgery. This study confirms that women wake up faster than men, but provides no explanation for this repeatedly shown difference.
-
Inorganic fluoride is released by the metabolism of enflurane and the increased serum fluoride concentrations may impair renal function. Tobacco smoke consists of numerous reactive compounds that can either induce or inhibit drug metabolism. Studies on the interaction of smoking with anaesthetic drug metabolism and possible toxicity are warranted. ⋯ Regular smoking is associated with an increase in serum inorganic fluoride concentration after anaesthesia with enflurane, but there are no signs of renal damage.
-
Comparative Study
Increased carbon dioxide absorption during retroperitoneal laparoscopy.
Retroperitoneoscopy for renal surgery is now a common procedure. We compared carbon dioxide absorption in patients undergoing retroperitoneoscopy for adrenal or renal surgery with that of patients undergoing laparoscopic cholecystectomy. ⋯ Retroperitoneal carbon dioxide insufflation causes more carbon dioxide absorption than intraperitoneal insufflation, and controlled ventilation should be increased if hypercapnia should be avoided.
-
At present, there is no rapid method for determining the plasma concentration of i.v. anaesthetics. A solution might be the measurement of the anaesthetic concentration in expired breath and its relation to the plasma concentration. We used chemical ionization methods to determine whether an i.v. anaesthetic can be detected in the low concentrations (parts per billion by volume) in the expired breath of an anaesthetized patient. ⋯ Routine measurement of i.v. agents, analogous to that for volatile anaesthetic agents, may be possible.