A Blinded Analysis Of Anesthesia Machine Scavenger System Calibration In An Academic Medical Center

摘要

Exposure to trace gases in the operating has long been recognized as a potential source of increased risk of health problems in operating room personnel (1). Analysis of this risk has not shown an increased risk of mortality in anesthesiologists, but the anesthetic technique used may affect operating room trace gas levels as well (2,3). For example, pediatric anesthesiologists who may frequently use masking techniques which increase exposure to anesthetic gases may have increased risk of obstetric complications (4). The initial set up of the anesthesia machine includes calibration of the scavenging system (5, see appendix A). The components of the system and setup techniques are well described; however the uniformity of knowledge of this setup is unclear. The goal of our study is was to assess the frequency of appropriate scavenger system setup in a major tertiary institution; to the author’s knowledge, there are no studies assessing the frequency of appropriate scavenger calibration. INTRODUCTION Exposure to trace gases in the operating has long been recognized as a potential source of increased risk of health problems in operating room personnel (1). Analysis of this risk has not shown an increased risk of mortality in anesthesiologists, but the anesthetic technique used may affect operating room trace gas levels as well (2,3). For example, pediatric anesthesiologists who may frequently use masking techniques which increase exposure to anesthetic gases may have increased risk of obstetric complications (4). The initial set up of the anesthesia machine includes calibration of the scavenging system (5, see appendix A). The components of the system and setup techniques are well described; however the uniformity of knowledge of this setup is unclear. The goal of our study is was to assess the frequency of appropriate scavenger system setup in a major tertiary institution; to the author’s knowledge, there are no studies assessing the frequency of appropriate scavenger calibration. METHODS Our study was conducted by checking every anesthesia machine in our academic hospitals’ main operating room suite on a weekday morning after setup had been completed but before a patient was brought into operating room. In order to achieve this, between 6:30AM and 7:00AM the investigator examined each operating room’s anesthesia machine to determine if the machine’s scavenging system was appropriately calibrated. The 6:30am time was chosen because the anesthesia resident morning conference takes place from 6:30AM to 7:00AM and the room/machine setup should be done by this time. The practitioners setting up the operating room were unaware/blinded of the study assessing how well calibrated their anesthesia machine was. An example of a normal anesthesia machine with the scavenging device circled is demonstrated in Figure 1. A close up image of this system is (which is on the lateral posterior aspect of the anesthesia machine) is shown in Figure 2. The calibration status was recorded by hand using a premade spreadsheet depicted in appendix B; a key describing the variables recorded are included in the appendix. No changes were made to the anesthesia machine during this project. Finally, the study investigator acquired the staffing arrangements for each operating room from the anesthesiologist directing the operating rooms that day. No patient information was requested or recorded at any point.Follow up checks of the anesthesia machines in the same location occurred one week later after the initial assessment to see if the machine was subsequently appropriately calibrated in the interim. No changes were made to the anesthesia machine at this time as well. The study investigator, again, acquired the staffing arrangements for each operating room from the anesthesiologist directing the operating rooms that day. As before, no patient information was requested or recorded. The data was subsequently analyzed for trends suggesting any difference between the