False-Positive Colorimetric Capnometry After Ingestion of Carbonated Beverages

Abstract

Under proper circumstances, a significant potential exists for false-positive colorimetric capnometric results in the presence of even small amounts of carbonated beverages.

Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies*

“…Failure to satisfy the criteria for sustained exhaled carbon dioxide following passage of a tracheal tube therefore requires oesophageal intubation to be actively excluded [ 8 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ]. Although in some circumstances exhaled carbon dioxide may be detected despite oesophageal intubation (Table 2 [ 12 , 91 , 95 , 96 , 97 ]), even these false positives will not typically result in sustained exhaled carbon dioxide. In rare situations, the first three criteria may be satisfied despite the tube being misplaced (e.g.…”

“…Tube removal is the most rapid and definitive method for excluding oesophageal intubation when the criteria for sustained exhaled carbon dioxide are not met. While there are other common causes for failure to meet the criteria for sustained exhaled carbon dioxide (Table 4 ) [ 96 , 97 , 106 , 107 ], unrecognised oesophageal intubation has catastrophic consequences, whereas there is usually low potential for harm if a tracheal tube is unnecessarily removed, particularly if airway management was straightforward. Furthermore, many causes of inability to meet the criteria for sustained exhaled carbon dioxide that occur despite tracheal placement still indicate absent alveolar ventilation (e.g.…”

“…Potential causes of failure to detect sustained exhaled carbon dioxide (CO 2 ) despite tracheal placement of tube[96,97,106,107]. Many of these will often be associated with additional clinical cues.…”

Using spectral reflectance to distinguish between tracheal and oesophageal tissue: applications for airway management

“…Unfortunately, end‐tidal carbon dioxide‐monitoring devices require several breaths to allow enough exposure for detection, can be compromised in some cases of cardiac arrest owing to low blood flow and insufficient levels of carbon dioxide produced and yield false positives when exposed to acidic contents (gastric contents) or drugs (e.g. lidocaine) . Despite the importance of end‐tidal carbon dioxide monitoring, there are greatly variable rates in its pre‐hospital use .…”

‘No trace, wrong place’ does not mean ‘positive trace, right place’. Identifying and managing misplaced or displaced tracheal tubes in cardiopulmonary resuscitation

“…Could anatomically incorrect (non‐tracheal) placement nevertheless facilitate sufficient alveolar ventilation to produce an attenuated ETCO 2 trace? Clearly not, if the tube is unambiguously in the oesophagus (notwithstanding reports of short‐lived false positive readings after recent ingestion of carbonated drinks [18]). But other non‐tracheal sites could allow this; a tube lying anywhere in the upper airway in a spontaneously breathing patient facilitates transmission of a carbon dioxide waveform.…”