Simple Simulation for Transportation of Remaining EOG in the Endotracheal Tube to the Intratracheal Tissue during Intubation

Abstract

It is well known that small amounts of sterilant "ethylene oxide" (EOG) generally remain in the disposable medical devices after sterilization.Several studies regarding tissue damage caused by residual EOG in the device have been reported.The simple simulations were done for the determination of amount of EOG transported from endotracheal tube to the intratracheal tissues during endotracheal intubation.The two methods used are as follow : That is, first as a simulation of the contact of the tube with living tissues, small pieces of the tubes were allowed to immerse in physiological saline solution at 37℃ and the content of EOG eluted from the outer surface of tube into saline was determined.Secondly, as a simulation for the release of EOG from the tube by simulated respiratory motion, the content of EOG released from the inner surface of the tube was determined by varying air-flow rate.From these studies, it is inferred that 0.90×10^<-3>〜1.94×10^<-3> of EOG transported to the tissue from the endotracheal tube, assuming that a patient is treated by intubation of the tube containing EOG at the safety level of 250 ppm (4.31×10^<-3> of EOG), giving by U.S.FDA regulation.