A Method to Detect Presence of Chest Compressions During Resuscitation Using Transthoracic Impedance

Aim of the study: To evaluate quality of cardiopulmonary resuscitation (CPR) performed by a physician-manned ambulance, and assess whether it changed with time influenced by developing scientific evidence and guideline changes. Materials and methods: Retrospective, observational study of all cardiac arrest patients (except trauma) older than 18 years treated between May 2003 and December 2006 by the physician-manned ambulance in Oslo. CPR quality was assessed from continuous electronic recordings from the defibrillators (LIFEPAK 12, Physio-Control or a modified Heartstart 4000, Philips Medical Systems). Ventilations were assessed from changes in transthoracic impedance, chest compressions from transthoracic impedance for LIFEPAK 12 and from an accelerometer for Heartstart 4000 (nine patients). Values are given as mean ± SD and differences analysed with ANOVA and unpaired Student’s t-test with Bonferroni correction. Results: Forty-eight of 169 consecutive cases were excluded from CPR quality analysis, 47 due to missing defibrillator data and one due to short arrest time (<1 min). Hands-off intervals (fraction of time without spontaneous circulation where no chest compressions are given) were reduced from 0.18±0.11 in 2003 to 0.10±0.06 in 2006 (p=0.03). Compression and ventilation rates were significantly reduced from 122±12 and 16±3 per minute respectively in 2003 to 111±10 and 12±3 in 2006 (p<0.0001 and p=0.001). In 2003–4 10% were discharged alive vs. 16 % in 2005–6 (p=0.3, Chi square test). Conclusion: High quality CPR is achievable out-of-hospital, and the improvement with time could reflect developing scientific evidence focusing on reducing hands-off intervals and hyperventilation. Quality of CPR from May 2003 to 2006.

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Automatic Detection Algorithm for Chest Compressions Signal with Classification Algorithm

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.926-930.3493 ◽

2014 ◽

Vol 926-930 ◽

pp. 3493-3496

Author(s):

Di Xiang

Keyword(s):

Cardiopulmonary Resuscitation ◽

Detection Algorithm ◽

Experimental Results ◽

Chest Compressions ◽

Multiple Sources ◽

Baseline Drift ◽

Transthoracic Impedance ◽

Potential Indicator ◽

Automatic Detection Algorithm

Transthoracic impedance (TTI) has been demonstrated to be a potential indicator to monitor the quality of chest compressions (CCs) during cardiopulmonary resuscitation (CPR). However, TTI signals are challenged by noise artifact from multiple sources, such as ventilations and baseline drift. Practically, it is very essential to accurately detect the peak-to-trough of the complicated TTI signals. However, nowadays, there is no method to solve the problem. In this paper, Extrima search with niche technology was used to search the peak-to-trough of TTI signal. We select 2 features to judge the potential peaks and troughs in order to remove the false ones. Besides, we designed a LDA classifier for recognizing the compression and ventilation waves. The experimental results show that this method in this paper can precisely recognize the real peaks and troughs of TTI signals which include some false ones.

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Assessment of the evolution of end-tidal carbon dioxide within chest compression pauses to detect restoration of spontaneous circulation

PLoS ONE ◽

10.1371/journal.pone.0251511 ◽

2021 ◽

Vol 16 (5) ◽

pp. e0251511

Author(s):

Jose Julio Gutiérrez ◽

Mikel Leturiondo ◽

Sofía Ruiz de Gauna ◽

Jesus María Ruiz ◽

Izaskun Azcarate ◽

...

Keyword(s):

Chest Compression ◽

Life Support ◽

Advanced Life Support ◽

Spontaneous Circulation ◽

Chest Compressions ◽

Average Value ◽

Transthoracic Impedance ◽

Single Feature ◽

End Tidal ◽

Hospital Cardiac Arrest

Background Measurement of end-tidal CO2 (ETCO2) can help to monitor circulation during cardiopulmonary resuscitation (CPR). However, early detection of restoration of spontaneous circulation (ROSC) during CPR using waveform capnography remains a challenge. The aim of the study was to investigate if the assessment of ETCO2 variation during chest compression pauses could allow for ROSC detection. We hypothesized that a decay in ETCO2 during a compression pause indicates no ROSC while a constant or increasing ETCO2 indicates ROSC. Methods We conducted a retrospective analysis of adult out-of-hospital cardiac arrest (OHCA) episodes treated by the advanced life support (ALS). Continuous chest compressions and ventilations were provided manually. Segments of capnography signal during pauses in chest compressions were selected, including at least three ventilations and with durations less than 20 s. Segments were classified as ROSC or non-ROSC according to case chart annotation and examination of the ECG and transthoracic impedance signals. The percentage variation of ETCO2 between consecutive ventilations was computed and its average value, ΔETavg, was used as a single feature to discriminate between ROSC and non-ROSC segments. Results A total of 384 segments (130 ROSC, 254 non-ROSC) from 205 OHCA patients (30.7% female, median age 66) were analyzed. Median (IQR) duration was 16.3 (12.9,18.1) s. ΔETavg was 0.0 (-0.7, 0.9)% for ROSC segments and -11.0 (-14.1, -8.0)% for non-ROSC segments (p < 0.0001). Best performance for ROSC detection yielded a sensitivity of 95.4% (95% CI: 90.1%, 98.1%) and a specificity of 94.9% (91.4%, 97.1%) for all ventilations in the segment. For the first 2 ventilations, duration was 7.7 (6.0, 10.2) s, and sensitivity and specificity were 90.0% (83.5%, 94.2%) and 89.4 (84.9%, 92.6%), respectively. Our method allowed for ROSC detection during the first compression pause in 95.4% of the patients. Conclusion Average percent variation of ETCO2 during pauses in chest compressions allowed for ROSC discrimination. This metric could help confirm ROSC during compression pauses in ALS settings.

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