ABSTRACT NO: 003
Introduction: The low blood/gas partition coefficient of xenon (0.14) leads to rapid induction and emergence from anaesthesia. An accumulation in fatty tissue is expected, because of a fat/gas coefficient of 1.3. Furthermore, a transfer to the bowel could occur. This study was designed to quantify the kinetics and accumulation of xenon in different tissues.
Methods: After approval by the Institutional Animal Care Committee, seven pigs were anaesthetized with pentobarbitone. After tracheal intubation and catheter placement, they were ventilated with a mixture of 70% xenon131 and the isotope xenon133 in oxygen for 4 h; this was followed by a washout phase of 2 h. Throughout, the animals lay under a gamma camera to determine the specific distribution and retention of xenon in the body, by means of the accumulation of xenon133. The whole-body uptake of xenon was also calculated from the xenon133 activity in the different tissues. Data are presented as mean ± SD.
Results: During 4 h of xenon anaesthesia, there was an accumulation of xenon in the fat tissue of 20.8 ± 3.3% and in the bowel of 28.8 ± 6.3%. The uptake of xenon during that time was 1.8 ± 0.4 L. The excretion half-life of the lung could be defined as 2.5 ± 0.4 min, the half-life of the fat tissue as 96.4 ± 21.3 min and that of the bowel as 125.2 ± 21.1 min.
Conclusions: The retention in fat tissue and bowel, in conjunction with the long half-life of these tissues, leads to a significant loss of xenon during longer-lasting xenon anaesthesia. Furthermore, xenon should be used carefully in patients with occlusion of the bowel.
The publication of this supplement has been supported by the sponsors of the Third ISMG Meeting: Abbott, AGA, AstraZeneca, Dräger, Janssen, Medex Medical, Messer Austria, Ohmeda, Pharmacia & Upjohn, Scott Medical Products, Siemens