Capnography and chest-wall impedance algorithms for ventilation detection during cardiopulmonary resuscitation

Abstract

Objective-Hyperventilation is both common and detrimental during cardiopulmonary resuscitation (CPR). Chest wall impedance algorithms have been developed to detect ventilations during CPR. However, impedance signals are challenged by noise artifact from multiple sources, including chest compressions. Capnography has been proposed as an alternate method to measure ventilations. We sought to assess and compare the adequacy of these two approaches.Methods-Continuous chest wall impedance and capnography were recorded during consecutive in-hospital cardiac arrests. Algorithms utilizing each of these data sources were compared to a manually determined "gold standard" reference ventilation rate. In addition, a combination algorithm, which utilized the highest of the impedance or capnography values in any given minute, was similarly evaluated.Results-Data were collected from 37 cardiac arrests, yielding 438 min of data with continuous chest compressions and concurrent recording of impedance and capnography. The manually calculated mean ventilation rate was 13.3±4.3/min. In comparison, the defibrillator's impedancebased algorithm yielded an average rate of 11.3±4.4/min (p=0.0001) while the capnography rate was 11.7±3.7/min (p=0.0009). There was no significant difference in sensitivity and positive predictive value between the two methods. The combination algorithm rate was 12.4±3.5/min (p=0.02), which yielded the highest fraction of minutes with respiratory rates within 2/min of the reference. The Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conclusions-Both the impedance and capnography-based algorithms underestimated the ventilation rate. Reliable ventilation rate determination may require a novel combination of multiple algorithms during resuscitation. Conflict of Interest

Part 5: Adult Basic Life Support

“…In a case series (LOE 4 110 ), capnography and chest-wall impedance algorithms were inaccurate for determining ventilation rate.…”

Reliability and accuracy of the thoracic impedance signal for measuring cardiopulmonary resuscitation quality metrics

“…The TI signal can be used to identify CCs 17,26-28 and ventilations. 17,[29][30][31][32] Although the compression depth is associated with outcome, it has been reported that it cannot be measured using the TI signal. 33,34 Therefore, the identification of CCs and ventilations in the TI only allows to evaluate quality metrics related to presence and rate.…”

“…Algorithms for CC detection using the TI signal are integrated into commercial software for episode reviewing, and algorithms for ventilation detection have been recently proposed using the TI. 29,30 Their global performance is provided in terms of sensitivity and positive predictive value (PPV). 26 Nevertheless, detailed analysis of the utility of the TI signal for CC/ventilation metrics is needed.…”

A Review of Carbon Dioxide Monitoring During Adult Cardiopulmonary Resuscitation

“…Interestingly, capnography has been proposed as a method of monitoring ventilation during CPR and is especially used in basic science experiments [8]. Edelson et al suggested that the use of capnography in combination with chest wall impedance from defibrillator pads may estimate more accurately the ventilation rate [73]. As a result, hyperventilation due to increased respiratory frequency may be prevented and thus haemodynamics during CPR may improve [74].…”