Air-oxygen flowmeter confusion.

Abstract

AnaesthesiaVolume 58, Issue 2 p. 194-195 Free Access Air – oxygen flowmeter confusion First published: 27 July 2005 https://doi.org/10.1046/j.1365-2044.2003.03005_17.xCitations: 2 The authors wish to acknowledge the assistance of Mr A. P. Rowlinson, Senior Biomedical Engineer, North Manchester General Hospital AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Previous letters to Anaesthesia have highlighted the ease with which an oxygen regulator/flowmeter can be attached to an air cylinder [1,2]. We report an incident in which a clinician mistakenly administered 100% air instead of 100% oxygen during the resuscitation of a patient. The gas was delivered when a bag valve and mask assembly was attached to an air flowmeter, which was correctly fitted into an air Schrader wall outlet. The essential problem seems to have been that in the ‘heat of the moment’ and the reduced lighting of the ward, the air and the oxygen flowmeters, and their respective wall outlets, appeared similar (Fig. 5). Figure 5 Open in figure viewerPowerPoint In theory, each of the component parts of the gas delivery system has several safety features designed to clearly identify the nature of the gas being delivered; the sum of these safety features should make it impossible to make a mistake. Although marking the Schrader outlet with the symbol of the gas is mandatory, colour coding seems to be optional (EN 737–1: 1998) [3]. ‘If colour coding is used, it shall be in accordance…’ with the standard for the marking of medical gas cylinders (1S032: 1997) [4]. Recently, the requirement for CE marking has led to a change in colour coding of Schrader outlets; hence, there may be two designs for the labelling of air outlets in a hospital (Fig. 6). The colour coding and annotation of the wall Schrader outlet may be obscured by the flowmeter (Fig. 5). Figure 6Open in figure viewerPowerPoint Within the standard for the manufacture of flowmeters (EN 13220 : 1999) [5], there is clear guidance that flow control valves should be clearly marked with the direction for increasing flow. However, as with EN 737–1, colour coding of components, such as the flow control valve and gas outlet nipple seems to be optional; though if colour coding is used, it must be black for air flowmeters, and white for oxygen flowmeters. Therefore, it is not possible to rely on the colour of the flow control valve or the nipple to definitively identify the gas, even at the time of purchase. In addition, the practice of annotating the flow control valve with the specific gas symbol is at the manufacturer's discretion. The situation is compounded by the fact that once a flowmeter is in use in a hospital, ward staff sometimes change the gas outlet nipple for any available colour. Thus, it can be seen that, in the ‘heat of the moment’, it is possible to confuse oxygen and air flowmeters, despite all existing anticonfusion devices, labelling and colour coding of the component parts. Since the event, we have ensured that air outlets are clearly identifiable by the use of high visibility signs (Fig. 7). Figure 7Open in figure viewerPowerPoint A. WaiteI. Macartney North Manchester General Hospital, Manchester M8 5RB, UK E-mail: NMGH.icu@virgin.net References 1 Arepalli N, Jones N. Oxygen or Air? Anaesthesia 2001; 56: 1205.CrossrefCASPubMedWeb of Science®Google Scholar 2 Thomas AN, Hurst W, Saha B. Interchangeable Oxygen and Air connectors. Anaesthesia 2001; 56: 1205.CrossrefCASPubMedWeb of Science®Google Scholar 3 EN. 737–1: 1998: Medical gas pipeline systems for patients. Terminal units for compressed medical gases and Vacuum. Google Scholar 4 ISO 32; 1997; Gas cylinders for medical use – marking for the identification of content. Google Scholar 5 EN. 13220: 1999: Flow metering devices for connection to terminal units of medical gas pipeline systems. Google Scholar Citing Literature Volume58, Issue2February 2003Pages 194-195 FiguresReferencesRelatedInformation