Continued breathing followed by gasping or apnea in a swine model of ventricular fibrillation cardiac arrest

Ventilation during cardiopulmonary resuscitation: A narrative review

Ventilation during cardiopulmonary resuscitation is vital to achieve optimal oxygenation but continues to be a subject of ongoing debate. This narrative review aims to provide an overview of various components and challenges of ventilation during cardiopulmonary resuscitation, highlighting key areas of uncertainty in the current understanding of ventilation management. It addresses the pulmonary pathophysiology during cardiac arrest, the importance of adequate alveolar ventilation, recommendations concerning the maintenance of airway patency, tidal volumes and ventilation rates in both synchronous and asynchronous ventilation. Additionally, it discusses ventilation adjuncts such as the impedance threshold device, the role of positive end-expiratory pressure ventilation, and passive oxygenation. Finally, this review offers directions for future research.

RESPIRATORY MECHANICS AND NEURAL RESPIRATORY DRIVE OF UNTREATED GASPING DURING CARDIAC ARREST IN A PORCINE MODEL

ABSTRACT

Introduction: Although the effects on hemodynamics of gasping during cardiac arrest (CA) have received a lot of attention, less is known about the respiratory mechanics and physiology of respiration in gasping. This study aimed to investigate the respiratory mechanics and neural respiratory drive of gasping during CA in a porcine model. Method: Pigs weighing 34.9 ± 5.7 kg were anesthetized intravenously. Ventricular fibrillation (VF) was electrically induced and untreated for 10 min. Mechanical ventilation (MV) was ceased immediately after the onset of VF. Hemodynamic and respiratory parameters, pressure signals, diaphragmatic electromyogram data, and blood gas analysis data were recorded. Results: Gasping was observed in all the animals at a significantly lower rate (2-5 gaps/min), with higher tidal volume ( VT ; 0.62 ± 0.19 L, P < 0.01), and with lower expired minute volume (2.51 ± 1.49 L/min, P < 0.001) in comparison with the baseline. The total respiratory cycle time and the expiratory time tended to be lengthened. Statistically significant elevations in transdiaphragmatic pressure, the pressure-time product of diaphragmatic pressure, and the mean of root mean square diaphragmatic electromyogram values (RMSmean) were observed ( P < 0.05, P < 0.05, and P < 0.001, respectively); however, VT /RMSmean and transdiaphragmatic pressure/RMSmean were reduced at all time points. The partial pressure of oxygen showed a continuous decline after VF to reach statistical significance in the 10th minute (9.46 ± 0.96 kPa, P < 0.001), whereas the partial pressure of carbon dioxide tended to first rise and then fall. Conclusions: Gasping during CA was characterized by high VT , extremely low frequency, and prolonged expiratory time, which may improve hypercapnia. During gasping, increased work of breathing and insufficient neuromechanical efficacy of neural respiratory drive suggested the necessity of MV and appropriate management strategies for MV during resuscitation after CA.

Prognostic value of gasping for short and long outcomes during out-of-hospital cardiac arrest: an updated systematic review and meta-analysis

Objective

We systematically reviewed the literature to investigate whether gasping could predict short and long outcomes in patients with out of hospital cardiac arrest (OHCA).

Methods

PubMed, Embase, and Cochrane Library were searched for observational studies regarding the prognostic effect of gasping on short and long outcomes in adults with OHCA. The primary outcome was return of spontaneous circulation (ROSC). The secondary outcomes were favorable neurological outcome at discharge or at 30 days after cardiac arrest;long term (≥6 months) survival; initial shockable rhythm.The Mantel-Haenszel method with random-effects model was used to calculate pooled relative risks (RRs) and 95% confidence intervals (CIs).

Results

Five studies (six cohorts) were included in the final analysis. In the pooled analysis, gasping was not only associated with a significant increase in ROSC (RR, 1.87; 95% CI, 1.64–2.13; I² = 70%), but also a high likelihood of favorable neurological outcomes (RR, 3.79; 95% CI, 1.86–7.73), long-term survival (RR, 3.46; 95% CI, 1.70–7.07), and initial shockable rhythm (RR, 2.25; 95% CI, 2.05–2.48).

Conclusions

Current evidence indicates that gasping can predict short and long outcomes in patients with OHCA.In addition, gasping is associated with a high likelihood of initial shockable rhythm,which may contribute to positive outcomes.

'She's sort of breathing': What linguistic factors determine call-taker recognition of agonal breathing in emergency calls for cardiac arrest?

BACKGROUND

In emergency ambulance calls, agonal breathing remains a barrier to the recognition of out-of-hospital cardiac arrest (OHCA), initiation of cardiopulmonary resuscitation, and rapid dispatch. We aimed to explore whether the language used by callers to describe breathing had an impact on call-taker recognition of agonal breathing and hence cardiac arrest.

METHODS

We analysed 176 calls of paramedic-confirmed OHCA, stratified by recognition of OHCA (89 cases recognised, 87 cases not recognised). We investigated the linguistic features of callers' response to the question "is s/he breathing?" and examined the impact on subsequent coding by call-takers.

RESULTS

Among all cases (recognised and non-recognised), 64% (113/176) of callers said that the patients were breathing (yes-answers). We identified two categories of yes-answers: 56% (63/113) were plain answers, confirming that the patient was breathing ("he's breathing"); and 44% (50/113) were qualified answers, containing additional information ("yes but gasping"). Qualified yes-answers were suggestive of agonal breathing. Yet these answers were often not pursued and most (32/50) of these calls were not recognised as OHCA at dispatch.

CONCLUSION

There is potential for improved recognition of agonal breathing if call-takers are trained to be alert to any qualification following a confirmation that the patient is breathing.

Cardiocerebral and cardiopulmonary resuscitation - 2017 update

Sudden cardiac arrest is a major public health problem in the industrialized nations of the world. Yet, in spite of recurrent updates of the guidelines for cardiopulmonary resuscitation and emergency cardiac care, many areas have suboptimal survival rates. Cardiocerebral resuscitation, a non‐guidelines approach to therapy of primary cardiac arrest based on our animal research, was instituted in Tucson (AZ, USA) in 2002 and subsequently adopted in other areas of the USA. Survival rates of patients with primary cardiac arrest and a shockable rhythm significantly improved wherever it was adopted. Cardiocerebral resuscitation has three components: the community, the pre‐hospital, and the hospital. The community component emphasizes bystander recognition and chest compression only resuscitation. Its pre‐hospital or emergency medical services component emphasizes: (i) urgent initiation of 200 uninterrupted chest compressions before and after each indicated single defibrillation shock, (ii) delayed endotracheal intubation in favor of passive delivery of oxygen by a non‐rebreather mask, (iii) early adrenaline administration. The hospital component was added later. The national and international guidelines for cardiopulmonary resuscitation and emergency medical services are still not optimal, for several reasons, including the fact that they continue to recommend the same approach for two entirely different etiologies of cardiac arrest: primary cardiac arrest, often caused by ventricular fibrillation, where the arterial blood oxygenation is little changed at the time of the arrest, and secondary cardiac arrest from severe respiratory insufficiency, where the arterial blood is severely desaturated at the time of cardiac arrest. These different etiologies need different approaches to therapy.

Advancing resuscitation science

PURPOSE OF REVIEW

To describe an alternative approach for improving survival of patients with out-of-hospital cardiac arrest (OHCA). The survival of patients with OHCA has been poor and relatively unchanged for decades in spite of recurrent national and international guidelines. Although there are exceptions, many thought and continue to think that any change in the guidelines for cardiopulmonary resuscitation should be based on randomized controlled trials in humans. However, many factors, including the need for informed consent, the marked variability of patients, and the variability of the type and quality of bystander and advanced resuscitation efforts, all make such studies problematic. Thus, potentially life-saving procedures are often withheld for decades, resulting in unnecessary loss of life.

RECENT FINDINGS

Many improvements in public health conditions have been made using models of continuous quality improvement. When applied to resuscitation science, once baseline data are obtained, changes based on reliable experimental findings are instituted and outcomes measured. This approach has now been shown to result in significant improvement in neurologically intact survival of patients with OHCA.

SUMMARY

Following this model, we found significant improvement in survival of patients with a witnessed OHCA primary cardiac arrest.

The association of gasping and outcome, in out of hospital cardiac arrest: A systematic review and meta-analysis

OBJECTIVE

Gasping is common after cardiac arrest, and its frequency decreases over time. The aim of this study was to conduct a meta-analysis to evaluate the association of gasping and survival to discharge in patients who suffered out-of-hospital cardiac arrest.

METHODS

Relevant studies were identified by searching in PubMed, Medline, Embase, OVID, Web of Science and Google Scholar. Risk ratios (RR) and 95% confidence intervals (CI) were calculated to assess the association of gasping and on out-of-hospital cardiac arrest outcomes. Heterogeneity, subgroup analysis, sensitivity analysis and publication bias were explored.

RESULTS

Individual patient data was obtained from 10,797 participants suffered out-of-hospital cardiac arrest in five cohort studies of 4 articles. A fixed effects model suggested that patients with gasping were 3.525 times (95% CI: 3.028-4.104; P<0.01) more likely to survive to discharge than those without gasping, and there was no heterogeneity among studies (P=0.564). Also it may be a favorable factor for return of spontaneous circulation (RR: 2.170; 95% CI: 1.691, 2.785) with high heterogeneity (Q=5.26; P=0.022).

CONCLUSIONS

Findings of this meta-analysis demonstrated that gasping is common after cardiac arrest, and is associated with increased survival to discharge. Patients who are cardiac arrest with gasping should be promptly resuscitated.

[Broncho-pulmonary aspiration of brain and cartilage tissue in a context of gasping]

Evidence of post-mortem breath movements are rarely reported. We present two cases of broncho-pulmonary aspiration of brain and cartilage tissue following two fatal suicidal gunshots to the head. We also discuss the physiopathological implications for the agony.

Cardiocerebral Resuscitation: An Approach to Improving Survival of Patients With Primary Cardiac Arrest

Out-of-hospital cardiac arrest (OHCA) is a major public health problem. In the United States, OHCA accounts for more premature deaths than any other cause. For over a half-century, the national "Guidelines" for resuscitation have recommended the same initial treatment of primary and secondary cardiac arrests. Using this approach, the overall survival of patients with OHCA, while quite variable, was generally very poor. One reason is that the etiologies of cardiac arrests are not all the same. The vast majority of nontraumatic OHCA in adults are due to a "primary" cardiac arrest, rather than secondary to respiratory arrest. Decades of research and ongoing reviews of the literature led the University of Arizona Sarver Heart Center Resuscitation Research Group to conclude in 2003 that the national guidelines for patients with primary cardiac arrest were not optimal. Therefore, we instituted a new, nonguidelines approach to the therapy of primary cardiac arrest that dramatically improved survival. We called this approach cardiocerebral resuscitation (CCR), as it is the heart and the brain that are the most vulnerable and therefore need to be the focus of resuscitation efforts for these patients. In contrast, cardiopulmonary resuscitation should be reserved for respiratory arrests. Cardiocerebral resuscitation evolved into 3 components: the community, with emphasis for lay individuals to "Check, Call, Compress" and use an automated external defibrillator if available; the Emergency Medical Services, that emphasizes delayed intubation in favor of passive ventilation, urgent and near continuous chest compressions before and immediately after a single indicated shock, and the early administration of epinephrine; and the third component, added in 2007, the designations of hospitals in Arizona that request this designation and agree to receive patients with return of spontaneous circulation following OHCA and to institute state-of-the-art postresuscitation care that includes urgent therapeutic mild hypothermia and cardiac catheterization as a Cardiac Receiving Center. Each component of CCR is critical for optimal survival of patients with primary OHCA. In each city, county, and state where CCR was instituted, the result was a marked increase in survival of the subgroup of patients with OHCA most likely to survive, for example, those with a shockable rhythm. The purpose of this invited article on CCR is to review this alternative approach to resuscitation of patients with primary cardiac arrest and to encourage its adoption worldwide so that more lives can be saved.

Role of manual and mechanical chest compressions during resuscitation efforts throughout cardiac arrest

The previously published randomized trials of mechanical versus manual resuscitation of patients with cardiac arrest are inconclusive, but a recent systematic review concluded: "There is no evidence that mechanical cardiopulmonary resuscitation devices improve survival; to the contrary they may worsen neurological outcome." However, in our view, none of the randomized trials to date are definitive as the manual groups with primary cardiac arrest have not been treated optimally; that is, with minimally interrupted manual chest compressions, as advocated with cardiocerebral resuscitation. Since the mechanical chest compression devices work on different principles, it is possible that, while they may not be as effective and may even be worse in some subsets of patients, they may be preferable in others. Nevertheless, there are situations where manual chest compressions are not practical and, in these, mechanical devices may well be preferable. The Thumper® (Michigan Instruments, MI, USA) and the LUCAS™ (Jolife AB, Lund, Sweden) devices produce sternal compressions at 100 per min. By contrast, the AutoPulse® (ZOLL Circulation, CA, USA) produces chest compressions at a rate of only 80 per min. Since chest compression rate, as reviewed in this article, is important, one would guess that the devices that can produce a faster rate would be more effective. On the other hand, it could be that sternal compressions with manual or mechanical devices may be more or less effective depending on the arrested patient's chest configuration. We speculate that in the subset of patients with barrel chests, where sternal compressions are less likely to be operative, the AutoPulse might be more effective, but less effective in thin-chested individuals, where direct cardiac compression is the major mechanism of forward blood flow in the manual, Thumper and LUCAS methods. The original LUCAS device had the potential of active decompression as well as compression. To market in the USA, holes had to be placed in the 'suction cup'. It would be informative to know whether the original LUCAS device is more effective than the device in which the active decompression has been deactivated.

Sudden cardiac arrest and death following application of shocks from a TASER electronic control device

BACKGROUND

The safety of electronic control devices (ECDs) has been questioned. The goal of this study was to analyze in detail cases of loss of consciousness associated with ECD deployment.

METHODS AND RESULTS

Eight cases of TASER X26 ECD-induced loss of consciousness were studied. In each instance, when available, police, medical, and emergency response records, ECD dataport interrogation, automated external defibrillator information, ECG strips, depositions, and autopsy results were analyzed. First recorded rhythms were ventricular tachycardia/fibrillation in 6 cases and asystole (after ≈ 30 minutes of nonresponsiveness) in 1 case. An external defibrillator reported a shockable rhythm in 1 case, but no recording was made. This report offers evidence detailing the mechanism by which an ECD can produce transthoracic stimulation resulting in cardiac electrical capture and ventricular arrhythmias leading to cardiac arrest.

CONCLUSIONS

ECD stimulation can cause cardiac electrical capture and provoke cardiac arrest resulting from ventricular tachycardia/ventricular fibrillation. After prolonged ventricular tachycardia/ventricular fibrillation without resuscitation, asystole develops.