Volatile Anesthetics Give a False-Positive Reading in Chemical Agent Monitors in the “H” Mode

Abstract

Chemical agent monitors (CAMs) are routinely used by the armed forces and emergency response teams of many countries for the detection of the vesicant sulfur mustard (HD) and the G series of organophosphate nerve agents. Ambient operating room isoflurane levels were found to produce strong positive signals in the "H" mode when the CAM was used to monitor the efficacy of decontamination procedures during routine surgical procedures on HD-poisoned animals requiring up to 8 hours of general anesthesia. Subsequent testing showed that isoflurane, as well as desflurane, sevoflurane, halothane and methoxyflurane, produce two ionization peaks in the CAM response. One of these peaks is interpreted by the CAM processing software as HD, resulting in a CAM "H" mode bar response. No interference was encountered with isoflurane, desflurane, and sevoflurane when the CAM was set to the "G" mode, although extremely high (nonclinical) concentrations of halothane and methoxyflurane yielded a weakly positive bar response. These findings have potentially serious ramifications for the medical management of patients resulting from terrorist, military, or chemical agent decommissioning activity when concomitant chemical injuries are also possible.

A primer on nerve agents: what the emergency responder, anesthesiologist, and intensivist needs to know

“…Isoflurane, desflurane, sevoflurane, and halothane can produce signals consistent with vesicant sulfur mustard (HD). 64 Opioids may be required as part of general anesthesia and to treat pain. They do not interact with the cholinergic receptors or AChEs.…”

Investigation of the Persistence of Nerve Agent Degradation Analytes on Surfaces through Wipe Sampling and Detection with Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry

“…Direct extraction of the surface or complete removal of contaminated material may be the most rigorous approach; however, it may not always be possible or desirable, especially when considering waste management costs. Field instrumentation can be used as a screening tool to identify areas where CWAs may exist; however, field instrumentation may result in false positives, − increasing the number of samples generated for analysis. Wipe sampling is a preferred collection procedure because it can be performed quickly and easily during the initial incident response and remediation phase without the destruction of the tested surface. ,, Complications associated with wipe sampling and analysis for both parent CWAs and their degradation analytes from surfaces should be considered.…”