Simulation and educationImproving the quality of cardiopulmonary resuscitation by training dedicated cardiac arrest teams incorporating a mechanical load-distributing device at the emergency department☆
Introduction
Sudden cardiac arrest is a global concern. The incidence of out-of-hospital cardiac arrest (OHCA) in USA has been estimated at 1.89/1000 person-years and at 5.98/1000 person-years in subjects with any clinically recognized heart disease.1 Published survival rates for OHCA ranged from 3.0% to 16.3% in North America.2
The problem with standard cardiopulmonary resuscitation (STD-CPR) is that it provides only one third of normal blood supply to the brain and 10–20% of normal blood flow to the heart.3 Thus there have been efforts to develop mechanical CPR as an alternative. It is also increasingly recognized that although defibrillation is the definitive treatment for ventricular fibrillation, its success is also dependent on adequate circulation.4, 5, 6 Thus effective CPR is often a prerequisite for effective defibrillation.
The Autopulse™ (Revivant Corporation, Sunnyvale, CA) is a non-invasive load-distributing band (LDB), mechanical CPR device that generates artificial circulation mechanically. LDB–CPR is based on the concept that distributing force over the entire chest improves the effectiveness of chest compressions by delivering more total energy to the torso. The device adjusts automatically to the size and shape of each patient and is constructed around a backboard that contains a motorized rotating shaft under microprocessor control. It utilizes a load-distributing band, which is connected to the rotating shaft to compress the chest. The band is tightened or relaxed around the chest rhythmically to provide a “squeezing” effect. The microprocessor is programmed to provide a consistent 20% reduction in the anterior–posterior dimension of the subject's chest during the compression phase. This would be equivalent to a compression depth of maximum 5 cm.
Other theoretical advantages of the mechanical CPR include elimination of rescuer fatigue factor and the need to stop CPR during rescuer changes and patient transfers, as well as more consistent and reliable chest compression. Additionally, distributing compressive force over the anterior chest may help to mitigate chest wall trauma, abdominal injury and thoracic visceral injury that occur frequently during STD-CPR.
However, survival outcomes from clinical trials with the LDB device have been conflicting. In a single center, phased, before–after clinical trial with 783 patients, the addition of the autopulse device to an EMS system was found to improve survival to discharge for out-of-hospital cardiac arrest patients.7 However a simultaneously reported clinical trial failed to find any significance difference between manual and LDB–CPR in their primary outcome of survival to 4 h or survival to discharge.8 Possible explanations for these unexpected results advanced by the authors included a Hawthorne effect for manual CPR, prolonged deployment time for the devices resulting in delayed defibrillation and enrollment bias.8 This study highlights the importance of incorporating the LDB device into overall treatment protocols in cardiac arrest resuscitations, to improve the quality of mechanical CPR by reducing interruptions to CPR and decreasing human-dependent variables such as deployment time.
Quality of CPR can be determined by various variables.9 The no-flow ratio (NFR) is a function of pauses to compressions in the CPR cycle, and thus a direct measure of device deployment efficiency as well. In this study, the objective is to determine if implementing cardiac arrest teams trained in a ‘pit-crew’ protocol incorporating a LDB device, improves the quality of CPR as determined by the NFR in the first 10 min of resuscitation in the ED.
Section snippets
Methods
We conducted a phased, prospective cohort evaluation with intention-to-treat analysis of adults with non-traumatic cardiac arrest. The intervention was implementation of cardiac arrest teams trained in a sequenced protocol (see Fig. 1) in deploying and using Autopulse™ in one urban ED. The study was approved by the hospital's ethics committee.
The ED in the study has been using LDB–CPR as standard of care since August 2007. This design was chosen because the ED implemented cardiac arrest teams
Results
A total of 248 patients were included in the study 100 in Phase 1 and 148 in Phase 2. Table 1 shows the characteristics of patients in the two phases. Patients in both phases were comparable for age and gender. There were significant differences in ethnicity, prevalence of respiratory disease and cause of collapse.
Table 2 shows the difference in quality of CPR between Phases 1 and 2. The mean NFR for the first 10 min decreased from 0.33 in Phase 1 to 0.23 (decrease = 0.10, 95% CI 0.07–0.14) in
Discussion
In our study, we found that a team resuscitation protocol significantly decreases the NFT and NFR in the first 5 min as well as the next 5 min of resuscitation. In the first 5 min, the reduction is attributed to decreased time taken to apply the LDB device and ensuring that hands-off time is kept within a reasonable range. In the next 5 min, the reduction in NFT and NFR can be attributed to being trained to check pulse, intubate, analyze cardiac rhythm and defibrillate even as the LDB device is
Conclusion
Implementation of cardiac arrest teams specially trained with a ‘pit-crew’ protocol in using a LDB device was associated with lower NFT and NFR in the first 5 min, next 5 min as well as overall first 10 min of resuscitation. This was probably due to shorter time taken to apply the LDB device in the first 5 min and reducing interruptions to compressions for procedures in the next 5 min. This translates into a better quality of mechanical CPR for the patient.
Conflict of interest statement
Dr. Marcus Ong has a patent filing and a licensing agreement with ZOLL Medical Corporation unrelated to the technology described in the study (Method of predicting acute cardiopulmonary events and survivability of a patient, application number: 13/047,348). All the other authors have neither commercial nor personal associations or any sources of support that might pose a conflict of interest in the subject matter or materials discussed in this manuscript.
Funding source
The study was funded by ZOLL Medical Corp. The funding sources had no involvement in the study design, collection, analysis, and interpretation of data, writing of manuscript, and in the decision to submit the manuscript for publication.
Acknowledgements
We would like to thank and acknowledge the contributions from all the doctors and nurses from Department of Emergency Medicine, Singapore General Hospital.
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Cited by (56)
Mechanical chest compression devices under special circumstances
2022, ResuscitationCitation Excerpt :Fourth, no information on the application of the device or the training status of the users was available for the analyses of this study. As already mentioned above, depending on the training level of the users, large differences in application and no-flow times can arise.24–27 This could have influenced the survival of the patients and thus the results of the work presented here, and should also be specifically examined in further studies.
Education, Implementation, and Teams: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations
2020, ResuscitationCitation Excerpt :The study randomized 32 internal medicine residents to receive simulation training with a focus on the role of the resuscitation team leader compared with no additional training but did not find an effect on CPR quality during actual resuscitation of patients. We also found very low-certainty evidence (downgraded for risk of bias, inconsistency, indirectness, and imprecision) from 4 observational studies110,224–226 that reported improved CPR depth, rate, ratio, team communication, and improved deployment times of mechanical devices. For the important outcome of skill performance at 3 to 15 months (patient tasks), we found very low-certainty evidence from 3 randomized trials (downgraded for risk of bias, inconsistency, and imprecision) that reported improvement in patient tasks.227–229
Out-of-hospital cardiac arrest: prehospital management
2018, The Lancet
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A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2012.07.033