Research Article The Use of Catheter Mount Will Result in More Reliable Carbon Dioxide Monitoring under Fluid Exposing Conditions Yongil Cho , 1 Wonhee Kim , 2,3 Tae Ho Lim , 1 Hyuk Joong Choi , 1 Jaehoon Oh , 1 Bossng Kang , 1 Youjin Kim, 4 and In Young Kim 3 1 Department of Emergency Medicine, College of Medicine, Hanyang University, Seoul, Republic of Korea 2 Department of Emergency Medicine, College of Medicine, Hallym University, Seoul, Republic of Korea 3 Department of Biomedical Engineering, College of Medicine, Hanyang University, Seoul, Republic of Korea 4 Department of Plant Biology, Rutgers, e State University of New Jersey, New Brunswick, New Jersey, USA Correspondence should be addressed to Wonhee Kim; wonsee02@gmail.com Received 2 April 2019; Revised 30 May 2019; Accepted 12 June 2019; Published 1 July 2019 Guest Editor: Yan-Ren Lin Copyright © 2019 Yongil Cho et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Capnometer can be readily malfunctioned by fuid exposure during treatment of critically ill patients. Tis study aimed to determine whether placing capnometer distant from the endotracheal tube by connecting direct connect catheter mount (DCCM) is efective in yielding reliable end-tidal carbon dioxide (ETCO 2 ) by reducing capnometer malfunctioning caused by water exposure. Methods. In 25 healthy adults, a prospective, open label, crossover study was conducted to examine the efect of DCCM in mainstream and microstream capnometers under water exposing conditions. Te primary endpoint was the comparison of ETCO 2 between proximal DCCM (pDCCM) and distal DCCM (dDCCM). Results. For mainstream capnometers, mean ETCO 2 was signifcantly (p < 0.001) higher in dDCCM compared to pDCCM under water exposing conditions (29.5 vs. 19.0 with 5 ml; 33.8 vs. 21.2 with 10 ml; mmHg). Likewise, for microstream capnometers, ETCO 2 was greatly higher (p < 0.001) in dDCCM compared to pDCCM (30.5 vs. 13.9 with 5 ml; 29.9 vs.11.4 with 10 mL; mmHg). ETCO 2 measured by dDCCM was reliable in microstream settings, whereas it was unreliable in mainstream (correlation coefcient 0.88 vs. 0.27). Conclusions. Application of DCCM onto the capnometer setting seems to be efective in reducing capnometer malfunctioning under fuid exposing conditions, which is obvious in microstream capnometer by producing more reliable ETCO 2 . 1. Introduction Capnometer is a device that measures end-tidal carbon dioxide (ETCO 2 ) by infrared sensor [1, 2]. Capnometer has been widely used to monitor proper placement of endotracheal tube (ETT) and status of ventilation [3, 4]. According to the 2010 American Heart Association (AHA) and European Resuscitation Council (ERC) guidelines, the use of capnometer is recommended during cardiopulmonary resuscitation (CPR), in order to evaluate quality of CPR and detect recovery of spontaneous circulation (ROSC) in intubated patients [5, 6]. During CPR, while low ETCO 2 (<10 mmHg) represents poor quality of CPR, a dramatic increase of ETCO 2 (up to 35-40 mmHg) indicates the occurrence of ROSC [6–8]. Accurate assessment of ETCO 2 is therefore essential to monitor placement of ETT and quality of CPR. Nevertheless, reliable ETCO 2 measurement by capnome- ter is difcult in clinical settings. ETCO 2 measurement becomes readily unreliable when capnometer is vulnerable to fuid exposure through ETT, mostly in cases of wet lung conditions [1, 4]. In wet lung conditions, fuid produced by patients is present in ETT, which interferes the infrared sensor on capnometer with detecting CO 2 absorption at 4.3 m wavelength, resulting in under- or oversensing ETCO 2 values. Furthermore, the sampling line connected to sidestream capnometer (i.e., microstream capnometer) is ofen occluded by condensed particles of fuid sourced from patients [1, 4]. Terefore, clinical settings of which patients Hindawi Emergency Medicine International Volume 2019, Article ID 4120127, 7 pages https://doi.org/10.1155/2019/4120127