Compound A concentrations
during sevoflurane anesthesia in children Frink EJ, Green WB, Brown EA et al; Anesthesiology
[ see abstract below ]
Compound A is produced by the degradation of sevoflurane. Sevoflurane
is gaining popularity for induction and maintenance of pediatic inhalation
anesthesia, and this paper quantifies the amount of Compound A produced
in this population.
ABSTRACT Background
Sevoflurane is a new inhalation agent that should be useful for pediatric anesthesia. Sevoflurane undergoes degradation in the presence of carbon dioxide adsorbents; however, quantification of the major degradation product (compound A) has not been evaluated during pediatric anesthesia.
This study evaluates sevoflurane degradation compound concentrations during sevoflurane anesthesia using a 2-1 fresh gas flow and a circle system with carbon dioxide absorber in children with normal renal and hepatic function.
Methods
The concentrations of compound A were evaluated during sevoflurane anesthesia in children using fresh soda lime as the carbon dioxide absorbent. Nineteen patients aged 3 months-7 yr were anesthetized with sevoflurane (2.8% mean end-tidal concentration) using a total fresh gas flow of 2 1 in a circle absorption system.
Inspiratory and expiratory limb circuit gas samples were obtained at hourly intervals, and the samples were analyzed using a gas chromatography-flame ionization detection technique. Carbon dioxide absorbent temperatures were measured in the soda lime during anesthesia. Blood samples were obtained before and after anesthesia for hepatic and renal function studies. Venous blood samples were obtained before anesthesia, at the end of anesthesia, and 2 h after anesthesia for plasma inorganic fluoride ion concentration.
Results
The maximum inspiratory concentration of compound A was 5.4 �4.4 ppm (mean � SD), and the corresponding expiratory concentration was 3.7 � 2.7 ppm (mean � SD). The maximum inspiratory compound A concentration in any patient was 15 ppm. Mean concentrations of compound A peaked at intubation and remained stable, declining slightly after 120 min of anesthesia.
The duration of anesthesia was 240 � 139 min (mean � SD). Maximum soda lime temperature fanged between 23.1 C and 40.9 C. There was a positive correlation between maximum absorbent temperature and maximum compound A concentration (r' = 0.58), as well as between the child's body surface area and maximum compound A concentration (r' = 0.59). Peak plasma inorganic fluoride Ion concentration was 21.5 � 6.1 umol/l. There were no clinically significant changes in hepatic or renal function studies performed 24 h postanesthesia.
Conclusions
Sevoflurane anesthesia of 4 h in normal children using a 2-1 flow circle system produced concentrations of compound A of 15 ppm or less. There was no evidence of abnormality of renal or hepatic function up to 24 h after anesthesia; however, larger studies will be required to confirm the absence of organ toxicity.
Received from the University of Arizona Health Sciences Center, Tucson, Arizona. Submitted for publication March 7, 1995. Accepted for Publication November 30, 1995. Supported in part by a grant from Abbott Laboratories. Presented in part at the annual meeting of the American Society of Anesthesiologists, San Francisco, California, October 15 -19, 1994.
Address reprint requests to Dr. Frink: Department of Anesthesiology, University of Arizona Health Sciences Center, P.O. Box 245114, Tucson, Arizona 85724-5 114.
