Production of compound A and carbon monoxide in circle systems: an in vitro comparison of two carbon dioxide absorbents.

Two new generation carbon dioxide absorbents, DrägerSorb Free and Amsorb Plus, were studied in vitro for formation of compound A or carbon monoxide, during minimal gas flow (500 ml x min(-1)) with sevoflurane or desflurane. Compound A was assessed by gas chromatography/mass spectrometry and carbon monoxide with continuous infrared spectrometry. Fresh and dehydrated absorbents were studied. Mean (SD) time till exhaustion (inspiratory carbon dioxide concentration >or= 1 kPa) with fresh absorbents was longer with DrägerSorb Free (1233 (55) min) than with Amsorb Plus (1025 (55) min; p < 0.01). For both absorbents, values of compound A were < 1 ppm and therefore below clinically significant levels, but were up to 0.25 ppm higher with DrägerSorb Free than with Amsorb Plus. Using dehydrated absorbents, values of compound A were about 50% lower than with fresh absorbents and were identical for DrägerSorb Free and Amsorb Plus. With dehydrated absorbents, no detectable carbon monoxide was found with desflurane.

Cost-reduction analysis of propofol versus sevoflurane: maintenance of anaesthesia for gynaecological surgery using the bispectral index.

BACKGROUND AND OBJECTIVE: The study was designed to compare the costs of propofol versus sevoflurane for the maintenance of the hypnotic component of anaesthesia during general anaesthesia, guided by the bispectral index, for gynaecological laparoscopic surgery. METHODS: Forty ASA Grade I-II female patients scheduled for gynaecological laparoscopy were randomly allocated to two groups. All patients received a continuous infusion of remifentanil (0.25 microg kg(-1) min(-1)) for 2 min. Then anaesthesia was induced with propofol 1% at 300 mL h(-1) until loss of consciousness. To guide the bispectral index between 40 and 60, Group 1 patients received propofol 10 mg kg(-1) h(-1) initially, which was increased or decreased by 2 mg kg(-1) h(-1) steps; Group 2 patients received sevoflurane, initially set at 2 vol.% and adjusted with steps of 0.2-0.4%. The time and quality of anaesthesia and recovery were assessed in two postoperative standardized interviews. RESULTS: Patient characteristics, the propofol induction dose, the bispectral index and the haemodynamic profiles during induction of anaesthesia, and its duration, were similar between the groups. In Group 1, 7.55 +/- 1.75 mg kg(-1) h(-1) propofol and in Group 2, 0.20 +/- 0.09 mL kg(-1) h(-1) liquid sevoflurane were used for maintenance. The cost for maintenance, including wasted drugs, was higher when using propofol (Euro 25.14 +/- 10.69) than sevoflurane (Euro 12.80 +/- 2.67). Postoperatively, recovery profiles tended to be better with propofol; however, the day after discharge no differences were found. CONCLUSIONS: When applying the bispectral index to guide the administration of hypnotic anaesthetic drugs, propofol-based maintenance of anaesthesia was associated with the highest cost. A trend towards a better recovery profile was obtained with propofol. However, on the day after discharge, no differences in quality were observed.