Complications of bystander cardiopulmonary resuscitation for unconscious patients without cardiopulmonary arrest

Performance of the Medical Priority Dispatch System® in Identifying Patients Requiring Chest Compressions at Overdose Prevention Services: A Retrospective Cohort Study

BACKGROUND AND AIMS

The Medical Priority Dispatch System (MPDS)® is used to triage 9-1-1 calls according to acuity, with certain coding receiving telecommunicator cardiopulmonary resuscitation (T-CPR) for suspected out-of-hospital cardiac arrest (OHCA). However, this may be challenging for those with drug poisoning emergencies, who may resemble OHCA. We sought to examine the performance of the system to correctly identify cases requiring T-CPR, specifically at overdose prevention services (OPS).

METHODS

This retrospective cohort study included patients attended by the provincial emergency medical system (EMS) (May 1, 2019-January 31, 2023). We calculated the diagnostic performance of MPDS® assessment of whether the case required T-CPR instructions against the gold standard of whether the patient was found pulseless on EMS clinician arrival. We compared performance among subgroups, specifically OPS vs other locations and drug poisoning-classified cases vs other case classifications.

RESULTS

Comparing OPS to other locations, the sensitivity of MPDS® was similar (66.7% vs 62.4%, p = 0.4), with lower specificity (87.3% vs 98.1%, p < 0.01) and positive predictive value (0.3% vs 35.7%, p < 0.01) and higher negative predictive value (99.9% vs 99.4%, p < 0.01). The negative likelihood ratio of MPDS® was 0.381 at OPS locations, compared with 0.383 at other locations, while the positive likelihood ratio was 5.24, compared with 32.36. In patients with drug poisoning emergencies, compared with other 9-1-1 events, MPDS® had higher sensitivity (83.6% vs 60.6%, p < 0.01) but lower specificity (77.6% vs 98.9%, p < 0.01) and positive predictive value (10.5% vs 48.5%, p < 0.01), and similar negative predictive value (99.33% vs 99.35%, p = 0.03). The negative likelihood ratio of MPDS® was 0.212 in drug poisoning emergencies compared with 0.398 for all other presentations, and the positive likelihood ratio was 3.73 compared with 57.88.

DISCUSSION AND CONCLUSIONS

The ability of MPDS® to correctly identify patients needing telecommunicator cardiopulmonary resuscitation instructions differed between OPS settings and other locations, frequently recommending T-CPR for patients not suffering OHCA at an OPS. Different strategies developed in collaboration with people who use substances are required to better tailor dispatch instructions prior to EMS arrival to avoid delays in life-saving interventions.

When the machine is wrong. Characteristics of true and false predictions of Out-of-Hospital Cardiac arrests in emergency calls using a machine-learning model

BACKGROUND

A machine-learning model trained to recognize emergency calls regarding Out-of-Hospital Cardiac Arrest (OHCA) was tested in clinical practice at Copenhagen Emergency Medical Services (EMS) from September 2018 to December 2019. We aimed to investigate emergency call characteristics where the machine-learning model failed to recognize OHCA or misinterpreted a call as being OHCA.

METHODS

All emergency calls were linked to the dispatch database and verified OHCAs were identified by linkage to the Danish Cardiac Arrest Registry. Calls with either false negative or false positive predictions of OHCA were evaluated by trained auditors. Descriptive analyses were performed with absolute numbers and percentages reported.

RESULTS

The machine-learning model processed 169,236 calls to Copenhagen EMS and suspected 5,811 (3.4%) of the calls as OHCA, resulting in 84.5% sensitivity and 97.1% specificity. Among OHCAs not recognised by machine-learning model, a condition completely different from OHCA was presented by caller in 31% of the cases. In 28% of unrecognised calls, patient was reported breathing normally, and language barriers were identified in 23% of the cases. Among falsely suspected OHCA, the patient was reported unconscious in 28% of the cases, and in 13% of the false positive cases the machine-learning model interpreted calls regarding dead patients with irreversible signs of death as OHCA.

CONCLUSION

Continuous optimization of the language model is needed to improve the prediction of OHCA and thereby improve sensitivity and specificity of the machine-learning model on recognising OHCA in emergency telephone calls.

A rare complication of cardiopulmonary resuscitation applied during transportation by ambulance: A case report of flail chest

Cardiopulmonary resuscitation (CPR) to be applied during patient transfer by ambulance differs from CPR applied in the field or in the hospital in terms of physical condition. Especially the deeper and faster chest compressions recommended in the latest CPR guidelines, when administered during ambulance transport, may result in a further increase in traumatic CPR complications. However, in the current CPR guidelines, there are no clear recommendations regarding additional measures that can be taken to reduce the complications and increase the efficiency of CPR during patient transport. In this study, a case of flail chest that developed after short-term CPR application during ambulance transport is presented. The aim of this study was to evaluate the flail chest complication and solution suggestions that may occur due to chest compressions applied during transportation.

On Assessing Trustworthy AI in Healthcare. Machine Learning as a Supportive Tool to Recognize Cardiac Arrest in Emergency Calls

Artificial Intelligence (AI) has the potential to greatly improve the delivery of healthcare and other services that advance population health and wellbeing. However, the use of AI in healthcare also brings potential risks that may cause unintended harm. To guide future developments in AI, the High-Level Expert Group on AI set up by the European Commission (EC), recently published ethics guidelines for what it terms “trustworthy” AI. These guidelines are aimed at a variety of stakeholders, especially guiding practitioners toward more ethical and more robust applications of AI. In line with efforts of the EC, AI ethics scholarship focuses increasingly on converting abstract principles into actionable recommendations. However, the interpretation, relevance, and implementation of trustworthy AI depend on the domain and the context in which the AI system is used. The main contribution of this paper is to demonstrate how to use the general AI HLEG trustworthy AI guidelines in practice in the healthcare domain. To this end, we present a best practice of assessing the use of machine learning as a supportive tool to recognize cardiac arrest in emergency calls. The AI system under assessment is currently in use in the city of Copenhagen in Denmark. The assessment is accomplished by an independent team composed of philosophers, policy makers, social scientists, technical, legal, and medical experts. By leveraging an interdisciplinary team, we aim to expose the complex trade-offs and the necessity for such thorough human review when tackling socio-technical applications of AI in healthcare. For the assessment, we use a process to assess trustworthy AI, called 1Z-Inspection® to identify specific challenges and potential ethical trade-offs when we consider AI in practice.

[Basic life support]

The European Resuscitation Council has produced these basic life support guidelines, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include cardiac arrest recognition, alerting emergency services, chest compressions, rescue breaths, automated external defibrillation (AED), cardiopulmonary resuscitation (CPR) quality measurement, new technologies, safety, and foreign body airway obstruction.

European Resuscitation Council Guidelines 2021: Basic Life Support

The European Resuscitation Council has produced these basic life support guidelines, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include cardiac arrest recognition, alerting emergency services, chest compressions, rescue breaths, automated external defibrillation (AED), CPR quality measurement, new technologies, safety, and foreign body airway obstruction.

Adult Basic Life Support: International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care Science With Treatment Recommendations on basic life support summarizes evidence evaluations performed for 20 topics that were prioritized by the Basic Life Support Task Force of the International Liaison Committee on Resuscitation. The evidence reviews include 16 systematic reviews, 3 scoping reviews, and 1 evidence update. Per agreement within the International Liaison Committee on Resuscitation, new or revised treatment recommendations were only made after a systematic review.

Systematic reviews were performed for the following topics: dispatch diagnosis of cardiac arrest, use of a firm surface for CPR, sequence for starting CPR (compressions-airway-breaths versus airway-breaths-compressions), CPR before calling for help, duration of CPR cycles, hand position during compressions, rhythm check timing, feedback for CPR quality, alternative techniques, public access automated external defibrillator programs, analysis of rhythm during chest compressions, CPR before defibrillation, removal of foreign-body airway obstruction, resuscitation care for suspected opioid-associated emergencies, drowning, and harm from CPR to victims not in cardiac arrest.

The topics that resulted in the most extensive task force discussions included CPR during transport, CPR before calling for help, resuscitation care for suspected opioid-associated emergencies, feedback for CPR quality, and analysis of rhythm during chest compressions. After discussion of the scoping reviews and the evidence update, the task force prioritized several topics for new systematic reviews.

Adult Basic Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This2020 International Consensus on Cardiopulmonary Resuscitation(CPR)and Emergency Cardiovascular Care Science With Treatment Recommendationson basic life support summarizes evidence evaluations performed for 22 topics that were prioritized by the Basic Life Support Task Force of the International Liaison Committee on Resuscitation. The evidence reviews include 16 systematic reviews, 5 scoping reviews, and 1 evidence update. Per agreement within the International Liaison Committee on Resuscitation, new or revised treatment recommendations were only made after a systematic review.

Systematic reviews were performed for the following topics: dispatch diagnosis of cardiac arrest, use of a firm surface for CPR, sequence for starting CPR (compressions-airway-breaths versus airway-breaths-compressions), CPR before calling for help, duration of CPR cycles, hand position during compressions, rhythm check timing, feedback for CPR quality, alternative techniques, public access automated external defibrillator programs, analysis of rhythm during chest compressions, CPR before defibrillation, removal of foreign-body airway obstruction, resuscitation care for suspected opioid-associated emergencies, drowning, and harm from CPR to victims not in cardiac arrest.

The topics that resulted in the most extensive task force discussions included CPR during transport, CPR before calling for help, resuscitation care for suspected opioid-associated emergencies, feedback for CPR quality, and analysis of rhythm during chest compressions. After discussion of the scoping reviews and the evidence update, the task force prioritized several topics for new systematic reviews.

Part 3: Adult Basic Life Support and Automated External Defibrillation: 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This review comprises the most extensive literature search and evidence evaluation to date on the most important international BLS interventions, diagnostics, and prognostic factors for cardiac arrest victims. It reemphasizes that the critical lifesaving steps of BLS are (1) prevention, (2) immediate recognition and activation of the emergency response system, (3) early high-quality CPR, and (4) rapid defibrillation for shockable rhythms. Highlights in prevention indicate the rational and judicious deployment of search-and-rescue operations in drowning victims and the importance of education on opioid-associated emergencies. Other 2015 highlights in recognition and activation include the critical role of dispatcher recognition and dispatch-assisted chest compressions, which has been demonstrated in multiple international jurisdictions with consistent improvements in cardiac arrest survival. Similar to the 2010 ILCOR BLS treatment recommendations, the importance of high quality was reemphasized across all measures of CPR quality: rate, depth, recoil, and minimal chest compression pauses, with a universal understanding that we all should be providing chest compressions to all victims of cardiac arrest. This review continued to focus on the interface of BLS sequencing and ensuring high-quality CPR with other important BLS interventions, such as ventilation and defibrillation. In addition, this consensus statement highlights the importance of EMS systems, which employ bundles of care focusing on providing high-quality chest compressions while extricating the patient from the scene to the next level of care. Highlights in defibrillation indicate the global importance of increasing the number of sites with public-access defibrillation programs. Whereas the 2010 ILCOR Consensus on Science provided important direction for the “what” in resuscitation (ie, what to do), the 2015 consensus has begun with the GRADE methodology to provide direction for the quality of resuscitation. We hope that resuscitation councils and other stakeholders will be able to translate this body of knowledge of international consensus statements to build their own effective resuscitation guidelines.

Comparison of complications secondary to cardiopulmonary resuscitation between out-of-hospital cardiac arrest and in-hospital cardiac arrest

OBJECTIVE

The aim of this study was to assess whether there was a significant difference in the complications of cardiopulmonary resuscitation (CPR) between out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) survivors using multidetector computed tomography (MDCT).

SUBJECTS AND METHODS

We performed a retrospective analysis of prospective registry data. We enrolled both OHCA and IHCA patients who underwent successful CPR. We classified chest injuries secondary to chest compression into rib fractures, sternum fractures, and uncommon complications such as lung contusions and extrathoracic complications. We compared these complications according to CPR locations. We also analysed risk factors for CPR complications using multiple regression analysis and classification and regression tree analysis.

RESULTS

During the study period, a total of 148 patients were included in the primary analysis. Rib fractures were detected more in OHCA survivors than in IHCA survivors (74 patients (83.2%) vs. 37 patients (62.7%), p=0.05), and frequency of multiple rib fractures was higher in OHCA survivors than IHCA survivors (69 patients (77.5%) vs. 34 patients (57.6%), p=0.01). Although other complications were not significantly different between the groups, there was a trend for OHCA survivors to sustain more serious and direct high-energy related complications. Older age, longer CPR, and OHCA were significantly associated with incidence of rib fractures, multiple rib fractures, and number of rib fractures.

CONCLUSIONS

Rib fractures were more likely to occur in OHCA survivors, and serious complications tended to occur more often in OHCA compared to IHCA survivors.

Aortic luminal thrombus and intramural hematoma after cardiopulmonary resuscitation

We describe the case of a patient with an intramural hematoma and floating thrombus after cardiopulmonary resuscitation. The 92-year old man had a cardiac arrest due to ventricular fibrillation and witnesses immediately initiated manual cardiopulmonary resuscitation. Transesophageal echocardiography was performed immediately on hospital admission because the patient was in cardiogenic shock. In addition to an akinetic anterior wall, examination of the descending thoracic aorta demonstrated an intramural hematoma and a floating intra-aortic thrombus at a distance of 40cm from the dental arch. There was no aortic dissection. The thrombus was attributed to aortic compression during cardiopulmonary resuscitation. Although the aortic thrombus and intramural hematoma were not associated with any complications in this patient, insertion of an intra-aortic balloon may have led to aortic rupture or embolic events. Transesophageal echocardiography should be performed, when available, prior to insertion of an intra-aortic balloon for counterpulsation in patients who have undergone cardiopulmonary resuscitation.

Risky locations for out-of-hospital cardiopulmonary arrest in a typical urban city

Background:

The aim of this study is to clarify the circumstances including the locations where critical events resulting in out-of-hospital cardiopulmonary arrest (OHCPA) occur.

Materials and Methods:

Subjects of this population-based observational case series study were the clinical records of patients with nontraumatic and nonneck-hanging OHCPA.

Results:

Of all 1546 cases, 10.3% occurred in a public place (shop, restaurant, workplace, stations, public house, sports venue, and bus), 8.3% on the street, 73.4% in a private location (victim's home, the homes of the victims’ relatives or friends or cheap bedrooms, where poor homeless people live), and 4.1% in residential institutions. In OHCPA occurring in private locations, the frequency of asystole was higher and the outcome was poorer than in other locations. A total of 181 OHCPA cases (11.7%) took place in the lavatory and 166 (10.7%) in the bathroom; of these, only 7 (3.9% of OHCPA in the lavatory) and none in the bath room achieved good outcomes. The frequencies of shockable initial rhythm occurring in the lavatory and in bath room were 3.7% and 1.1% (lower than in other locations, P = 0.011 and 0.002), and cardiac etiology in OHCPA occurring in these locations were 46.7% and 78.4% (the latter higher than in other locations, P < 0.001).

Conclusions:

An unignorable population suffered from OHCPA in private locations, particularly in the lavatory and bathroom; their initial rhythm was usually asystole and their outcomes were poor, despite the high frequency of cardiac etiology in the bathroom. We should try to treat OHCPA victims and to prevent occurrence of OHCPA in these risky spaces by considering their specific conditions.

Etiology of out-of-hospital cardiac arrest diagnosed via detailed examinations including perimortem computed tomography

CONTEXT

The spectrum of the etiology of out-of-hospital cardiopulmonary arrest (OHCPA) has not been established. We have performed perimortem computed tomography (CT) during cardiopulmonary resuscitation.

AIMS

To clarify the incidence of non-cardiac etiology (NCE), actual distribution of the causes of OHCPA via perimortem CT and its usefulness.

SETTINGS AND DESIGN

Population-based observational case series study.

MATERIALS AND METHODS

We reviewed the medical records of 1846 consecutive OHCPA cases and divided them into two groups: 370 showing an obvious cause of OHCPA with NCE (trauma, neck hanging, terminal stage of malignancy, and gastrointestinal bleeding) and others.

RESULTS

Of a total OHCPA, perimortem CT was performed in 57.5% and 62.5% were finally diagnosed as NCE: Acute aortic dissection (AAD) 8.07%, pulmonary thrombo-embolization (PTE) 1.46%, hypoxia due to pneumonia 5.25%, asthma and acute worsening of chronic obstructive pulmonary disease 2.06%, cerebrovascular disorder (CVD) 4.48%, airway obstruction 7.64%, and submersion 5.63%. The rates of patients who survived to hospital discharge were 6-14% in patients with NCE. Out of the 1476 cases excluding obvious NCE of OHCPA, 66.3% underwent perimortem CT, 14.6% of cases without obvious NCE and 22.1% of cases with perimortem CT were confirmed as having some NCE.

CONCLUSIONS

Of the total OHCPA the incidences of NCE was 62.5%; the leading etiologies were AAD, airway obstruction, submersion, hypoxia and CVD. The rates of cases converted from cardiac etiology to NCE using perimortem CT were 14.6% of cases without an obvious NCE.