Einfluss von niedrigem Alkalimetallgehalt im Atemkalk auf Compound-A-Bildung während Low-flow-Narkosen mit Sevofluran

Abstract

The alkali hydroxide content in soda lime induces Compound A formation from Sevoflurane (Sevo). This study was designed to answer the question if the use of potassium hydroxide-free Soda Lime (SL) would lead to lower Compound A levels as compared to Sodasorb (SO). A total of 30 patients scheduled for elective laparoscopic cholecystectomy received Sevo anaesthesia under low-flow conditions (0.8 l/min fresh gas flow). Each absorbent was used in 15 patients, but 3 patients of the SO group were excluded due to technical problems with Compound A analysis. Hemodynamic parameters, parameters of ventilation and gas concentrations were documented. Compound A concentrations were measured by gas chromatography from gas samples before Sevo application and 20, 40, 60, 90 and 120 min after low-flow start. Mean endtidal Sevo concentrations were 1.94 +/- 0.17 (SO) and 1.97 +/- 0.15 (SL) vol %, the total anaesthetic exposition was 1.52 +/- 0.36 (SO) and 1.64 +/- 0.47 (SL) MAC-h (n.s). The maximum Compound A concentration was significantly higher in SL group (19.6 +/- 2.8 vs. 11.7 +/- 4.1 ppm, p < 0.001). Therefore, elimination of potassium hydroxide from carbon dioxide absorbents alone did not lead to a reduction of Compound A formation during low-flow anaesthesia.

Sevofluran [MAK Value Documentation in German language, 2013]

“…Abschnitt 3.2), wurde in mehreren Studien untersucht. Compound A wird schon in den ersten Minuten nach Narkosebeginn in der eingeatmeten Luft nachgewiesen(Reichle et al 2001). Die mittlere Konzentration an eingeatmeter Compound Ab ei Patienten betrug nach Sevofluran-Narkose 16 ±6ml/m 3 ,d er Maximalwert lag bei 25 ±9ml/m 3 .D er AUC-Wert für eine Narkosedauer von 9,1 ±3 ,0 Stunden wird mit 165 ±9 5m l/m 3 ×S tunde angegeben(Kharasch et al 2001).…”