Correction: Real-time feedback improves chest compression quality in out-of-hospital cardiac arrest: A prospective cohort study.

[This corrects the article DOI: 10.1371/journal.pone.0229431.].

Real-time feedback improves chest compression quality in out-of-hospital cardiac arrest: A prospective cohort study.

BACKGROUND: Current guidelines underline the importance of high-quality chest compression during cardiopulmonary resuscitation (CPR), to improve outcomes. Contrary to this many studies show that chest compression is often carried out poorly in clinical practice, and long interruptions in compression are observed. This prospective cohort study aimed to analyse whether chest compression quality changes when a real-time feedback system is used to provide simultaneous audiovisual feedback on chest compression quality. For this purpose, pauses in compression, compression frequency and compression depth were compared. METHODS: The study included 292 out-of-hospital cardiac arrests in three consecutive study groups: first group, conventional resuscitation (no-sensor CPR); second group, using a feedback sensor to collect compression depth data without real-time feedback (sensor-only CPR); and third group, with real-time feedback on compression quality (sensor-feedback CPR). Pauses and frequency were analysed using compression artefacts on electrocardiography, and compression depth was measured using the feedback sensor. With this data, various parameters were determined in order to be able to compare the chest compression quality between the three consecutive groups. RESULTS: The compression fraction increased with sensor-only CPR (group 2) in comparison with no-sensor CPR (group 1) (80.1% vs. 87.49%; P < 0.001), but there were no further differences belonging compression fraction after activation of sensor-feedback CPR (group 3) (P = 1.00). Compression frequency declined over the three study groups, reaching the guideline recommendations (127.81 comp/min vs. 122.96 comp/min, P = 0.02 vs. 119.15 comp/min, P = 0.008) after activation of sensor-feedback CPR (group 3). Mean compression depth only changed minimally with sensor-feedback (52.49 mm vs. 54.66 mm; P = 0.16), but the fraction of compressions with sufficient depth (at least 5 cm) and compressions within the recommended 5-6 cm increased significantly with sensor-feedback CPR (56.90% vs. 71.03%; P = 0.003 and 28.74% vs. 43.97%; P < 0.001). CONCLUSIONS: The real-time feedback system improved chest compression quality regarding pauses in compression and compression frequency and facilitated compliance with the guideline recommendations. Compression depth did not change significantly after activation of the real-time feedback. Even the sole use of a CPR-feedback-sensor ("sensor-only CPR") improved performance regarding pauses in compression and compression frequency, a phenomenon known as the 'Hawthorne effect'. Based on this data real-time feedback systems can be expected to raise the quality level in some parts of chest compression quality. TRIAL REGISTRATION: International Clinical Trials Registry Platform of the World Health Organisation and German Register of Clinical Trials (DRKS00009903), Registered 09 February 2016 (retrospectively registered).

Predicting ROSC in out-of-hospital cardiac arrest using expiratory carbon dioxide concentration: Is trend-detection instead of absolute threshold values the key?

AIM: Guidelines recommend detecting return of spontaneous circulation (ROSC) by a rising concentration of carbon dioxide in the exhalation air. As CO2 is influenced by numerous factors, no absolute cut-off values of CO2 to detect ROSC are agreed on so far. As trends in CO2 might be less affected by influencing factors, we investigated an approach which is based on detecting CO2-trends in real-time. METHODS: We conducted a retrospective case-control study on 169 CO2 time series from out of hospital cardiac arrests resuscitated by Muenster City Ambulance-Service, Germany. A recently developed statistical method for real-time trend-detection (SCARM) was applied to each time series. For each series, the percentage of time points with detected positive and negative trends was determined. RESULTS: ROSC time series had larger percentages of positive trends than No-ROSC time series (p=0.003). The median percentage of positive trends was 15% in the ROSC time series (IQR: 5% to 23%) and 7% in the No-ROSC time series (IQR: 3% to 14%). A receiver operating characteristic (ROC) analysis yielded an optimal threshold of 13% to differentiate between ROSC and No-ROSC cases with a specificity of 58.4% and sensitivity of 73.9%; the area under the curve was 63.5%. CONCLUSION: Patients with ROSC differed from patients without ROSC as to the percentage of detected CO2 trends, indicating the potential of our real-time trend-detection approach. Since the study was designed as a proof of principle and its calculated specificity and sensitivity are low, more research is required to implement CO2-trend-detection into clinical use.

Senior citizens as rescuers: Is reduced knowledge the reason for omitted lay-resuscitation-attempts? Results from a representative survey with 2004 interviews.

OBJECTIVE: Resuscitation (CPR) provided by a bystander prior to the arrival of the emergency services is a beneficial factor for surviving a cardiac arrest (CA). Our registry-based data show, that older patients receive bystander-CPR less frequently. Little is known on possible reasons for this finding. We sought to investigate the hypothesis that awareness of CPR measures is lower in older laypersons being a possible reason for less CPR-attempts in senior citizens. METHODS: 1206 datasets on bystander resuscitations actually carried out were analyzed for age-dependent differences. Subsequently, we investigated whether the knowledge required carrying out bystander-CPR and the self-confidence to do so differ between younger and older citizens using computer-assisted telephone interviewing. 2004 interviews were performed and statistically analyzed. RESULTS: A lower level of knowledge to carry out bystander-CPR was seen in older individuals. For example, 82.4% of interviewees under 65 years of age, knew the correct emergency number. In this group, 66.6% named CPR as the relevant procedure in CA. Among older individuals these responses were only given by 75.1% and 49.5% (V = 0.082; P < 0.001 and V = 0.0157; P < 0.001). Additionally, a difference concerning participants' confidence in their own abilities was detectable. 58.0% of the persons younger than 65 years were confident that they would detect a CA in comparison to 44.6% of the participants older than 65 years (V = 0.120; P < 0.001). Similarly, 62.7% of the interviewees younger than 65 were certain to know what to do during CPR compared to 51.3% of the other group (V = 0.103; P < 0.001). CONCLUSIONS: Lower levels of older bystanders' knowledge and self-confidence might provide an explanation for why older patients receive bystander-CPR less frequently. Further investigation is necessary to identify causal connections and optimum ways to empower bystander resuscitation.

Kids save lives: a six-year longitudinal study of schoolchildren learning cardiopulmonary resuscitation: Who should do the teaching and will the effects last?

AIMS: This prospective longitudinal study over 6 years compared schoolteachers and emergency physicians as resuscitation trainers for schoolchildren. It also investigated whether pupils who were trained annually for 3 years retain their resuscitation skills after the end of this study. METHODS: A total of 261 pupils (fifth grade) at two German grammar schools received resuscitation training by trained teachers or by emergency physicians. The annual training events stopped after 3 years in one group and continued for 6 years in a second group. We measured knowledge about resuscitation (questionnaire), chest compression rate (min(-1)), chest compression depth (mm), ventilation rate (min(-1)), ventilation volume (mL), self-efficacy (questionnaire). Their performance was evaluated after 1, 3 and 6 years. RESULTS: The training events increased the pupils' knowledge and practical skills. When trained by teachers, the pupils achieved better results for knowledge (92.86% ± 8.38 vs. 90.10% ± 8.63, P=0.04) and ventilation rate (4.84/min ± 4.05 vs. 3.76/min ± 2.37, P=0.04) than when they were trained by emergency physicians. There were no differences with regard to chest compression rate, depth, ventilation volume, or self-efficacy at the end of the study. Knowledge and skills after 6 years were equivalent in the group with 6 years training compared with 3 years training. CONCLUSIONS: Trained teachers can provide adequate resuscitation training in schools. Health-care professionals are not mandatory for CPR training (easier for schools to implement resuscitation training). The final evaluation after 6 years showed that resuscitation skills are retained even when training is interrupted for 3 years.

Difficult intubation and outcome after out-of-hospital cardiac arrest: a registry-based analysis.

BACKGROUND: Airway management during resuscitation attempts is pivotal for treating hypoxia, and endotracheal intubation is the standard procedure. This German Resuscitation Registry analysis investigates the influence of airway management on primary outcomes after out-of-hospital cardiac arrest, in a physician-based emergency system. METHODS: A total of 8512 patients recorded in the German Resuscitation Registry (2007-2011) were analyzed. The Return of Spontaneous Circulation After Cardiac Arrest (RACA) score was used to compare observed return of spontaneous circulation (ROSC) rates with the ROSC predicted by the score and to analyze factors influencing the primary outcome. Patients were classified into three groups: difficult intubation, impossible intubation, and a control group with normal airways. RESULTS: The observed ROSC matched the predicted ROSC in the group with difficult airways. The impossible intubation group had lower ROSC rates (31.3% vs. 40.5%; P < 0.05). Impossible intubation was more frequent in men (OR 2.28; 95% CI, 1.43-3.63; P = 0.001), young patients (OR 2.18; 95% CI, 1.26-3.76; P = 0.005) and those with trauma (OR 2.22; 95% CI, 1.01-4.85; P = 0.046). Fewer impossible intubations were reported when the emergency physicians were anesthesiologists (OR 0.65; 95% CI, 0.44-0.96; P = 0.028). If a supraglottic airway device was not used in the impossible intubation group, the observed ROSC (18.0%; 95% CI, 7.4-28.6%) was poorer than predicted (38.2%) (P < 0.05). CONCLUSIONS: Outcomes after resuscitation attempts are poorer when endotracheal intubation is not possible. Predictive factors for impossible intubation are male gender, younger age, and trauma. Supraglottic airway devices should be used at an early stage whenever these negative factors are present.

Chest compression depth after change in CPR guidelines--improved but not sufficient.

AIMS: Cardiopulmonary resuscitation is one of the most vital therapeutic options for patients with cardiac arrest. Sufficient chest compression depth turned out to be of utmost importance to increase the likelihood of a return of spontaneous circulation. Furthermore, the use of real-time feedback-systems for resuscitation is associated with improvement of compression quality. The European Resuscitation Council changed their recommendation about minimal compression depth from 2005 (40 mm) to 2010 (50 mm). The aim of the present study was to determine whether this recommendation of the new guidelines was implemented successfully in an emergency medical service using a real-time feedback-system and to what extend a guideline-based CPR training leads to a "change in behaviour" of rescuers, respectively. METHODS AND RESULTS: The electronic resuscitation data of 294 patients were analyzed retrospectively within two observational periods regarding fulfilment of the corresponding chest compression guideline requirements: ERC 2005 (40 mm) 01.07.2009-30.06.2010 (n=145) and ERC 2010 (50mm) 01.07.2011-30.06.2012 (n=149). The mean compression depth during the first period was 47.1mm (SD 11.1) versus 49.6 mm (SD 12.0) within the second period (p<0.001). With respect to the corresponding ERC Guidelines 2005 and 2010, the proportion of chest compressions reaching the minimal depth decreased (73.9% vs. 49.1%) (p<0.001). There was no correlation between compression depth and patient age, sex or duration of resuscitation. CONCLUSIONS: The present study was able to show a significant increase in chest compression depth after implementation of the new ERC guidelines. Even by using a real-time feedback system we failed to sustain chest compression quality at the new level as set by ERC Guidelines 2010. In consequence, the usefulness of a fixed chest compression depth should be content of further investigations.

[Teaching resuscitation in schools: "The earlier, the better...."]. / Laienreanimation--Reanimation als Schulfach: "Was Hänschen nicht lernt "

Sudden cardiac arrest is a major contributor to avoidable deaths in Europe. Immediate start of basic life support (BLS) by laypersons is among the most successful strategies in the treatment of cardiac arrest patients. Despite the fact that more than half of all cardiac arrests in Germany are witnessed by a bystander, only in one fifth of all arrests layperson resuscitation is initiated. One strategy to enhance bystander BLS is to establish cardiac resuscitation tuition in schools. BLS instructions for pupils have been proven to be successfully implemented independent from children's age or physical ability. Although an age-adjusted curriculum seems reasonable even usage of automatic external defibrillators (AED) can be taught effectually. The earlier in the life of a student BLS-instruction begins, the more successful the training is. However a national German curriculum for BLS-training in schools has yet to be established in Germany.

Cardiopulmonary resuscitation guidance improves medical students' adherence to guidelines in simulated cardiac arrest: a randomised cross-over study.

BACKGROUND: The 2010 Resuscitation Guidelines require high-quality chest compression and rapid defibrillation for patients with ventricular fibrillation with rhythm analysis and defibrillation repeated every 2 min. A lack of adherence to the guidelines by medical students was observed during simulated resuscitation training. OBJECTIVES: To assess whether real-time cardiopulmonary resuscitation guidance, including an audiovisual countdown timer, a metronome, a display of the chest compression quality and voice prompts, might improve adherence to the guidelines by medical students. DESIGN: Randomised cross-over simulation study. SETTING: Studienhospital Münster, Faculty of Medicine University Münster, Germany PARTICIPANTS: One hundred and forty-one medical students (fifth year) in 47 teams. INTERVENTION: Simulated resuscitation with and without real-time cardiopulmonary resuscitation guidance. MAIN OUTCOME MEASURES: The preshock pause, postshock pause, fraction of time without chest compression and defibrillation intervals. Observed quality parameters were chest compression depth and chest compression rate. RESULTS: With real-time cardiopulmonary resuscitation guidance, there were improved mean (SD) chest compression rates (105 ±â€Š8 vs. 121 ±â€Š12 bpm; P < 0.005), fewer inappropriate shock intervals [median (interquartile range) 0 (1 to 5) vs. 4 (1 to 7); P < 0.005], a smaller fraction of time without chest compression (18.9 ±â€Š4.4 vs. 22.5 ±â€Š7.0%; P < 0.005) and shorter postshock pauses (2.3 ±â€Š0.9 vs. 3.4 ±â€Š1.2 s; P < 0.005). CONCLUSION: Real-time cardiopulmonary resuscitation guidance significantly increased adherence to the guidelines by medical students treating simulated out-of-hospital cardiac arrest. Using a simple tool such as a countdown timer makes it possible to reduce the number of inappropriate shock intervals and time without chest compression.

Chest compression quality management and return of spontaneous circulation: a matched-pair registry study.

AIMS: Investigating the effects of any intervention during cardiac arrest remains difficult. The ROSC after cardiac arrest score was introduced to facilitate comparison of rates of return of spontaneous circulation (ROSC) between different ambulance services. To study the influence of chest compression quality management (including training, real-time feedback devices, and debriefing) in comparison with conventional cardiopulmonary resuscitation (CPR), a matched-pair analysis was conducted using data from the German Resuscitation Registry, with the calculated ROSC after cardiac arrest score as the baseline. METHODS AND RESULTS: Matching for independent ROSC after cardiac arrest score variables yielded 319 matched cases from the study period (January 2007-March 2011). The score predicted a 45% ROSC rate for the matched pairs. The observed ROSC increased significantly with chest compression quality management, to 52% (P=0.013; 95% CI, 46-57%). No significant differences were seen in the conventional CPR group (47%; 95% CI, 42-53%). The difference between the observed ROSC rates was not statistically significant. CONCLUSIONS: Chest compression quality management leads to significantly higher ROSC rates than those predicted by the prognostic score (ROSC after cardiac arrest score). Matched-pair analysis shows that with conventional CPR, the observed ROSC rate was not significantly different from the predicted rate. Analysis shows a trend toward a higher ROSC rate for chest compression quality management in comparison with conventional CPR. It is unclear whether a single aspect of chest compression quality management or the combination of training, real-time feedback, and debriefing contributed to this result.