Bag-Valve-Mask Ventilation and Survival From Out-of-Hospital Cardiac Arrest: A Multicenter Study

Effect of different airway devices on ventilation during cardiopulmonary resuscitation

PURPOSE

This study compared face mask, supraglottic airway device (SGA), and endotracheal tube (ETT) ventilation with mechanical ventilation (MV) during cardiopulmonary resuscitation (CPR) in the flat position and with head and thorax elevation (HTE).

METHODS

Using thawed, fresh-frozen human cadavers this randomized cross-over study compared face mask, SGA, and ETT ventilation using an automated ventilator in the flat and HTE positions. Tidal volume (TV) was set to 8 mL/kg ideal predicted body weight, and expiratory TV (VTe) (mL/kg) was the primary endpoint. Secondary endpoints included inspiratory TV (VTi), maximal inspiratory airway pressure (Pmax), and leakage between inspiratory and expiratory tidal volumes (VTi-VTe).

RESULTS

Data from 8 cadavers and 2302 ventilation cycles were analyzed. In the flat position, VTe was 7.66 ± 3.75 with ETT, 5.01 ± 3.14 with SGA, and 5.63 ± 2.83 with face mask, respectively. A mixed linear model showed the airway device significantly impacted VTe, VTi, Pmax, and VTi-VTe (p < 0.001 for each). Compared with intubation, both face mask and SGA ventilation resulted in lower VTe, lower Pmax, and higher VTi-VTe (p < 0.001 for each). No significant differences were observed between face mask and SGA ventilation. There were higher VTe and lower VTi-VTe values (p < 0.001 for each) with HTE versus the flat position (p < 0.001).

CONCLUSIONS

In human cadavers undergoing CPR, mechanical ventilation through a face mask or SGA versus an ETT was associated with lower VTe, lower Pmax, and higher leakage values in human cadavers during CPR. Head and thorax elevation reduce face mask and SGA airway leakage during CPR and increase VTe.

Registration of transthoracic impedance signal and ventilation volume data in out-of-hospital cardiac arrest

Studying ventilation during out-of-hospital cardiac arrest (OHCA) presents significant challenges due to the limited methods available for monitoring ventilation during Basic Life Support care. Researchers are increasingly focusing on transthoracic impedance (TTI) as a new means of investigating ventilation. We employed manual ventilation monitoring devices to record cardiopulmonary resuscitation (CPR), ventilation volumes (Vvol) and TTI data. A registration of TTI with Vvol signals is performed. The Vvol are considered as the ground truth for ventilation detection in our dataset. The latter comprises data recorded during OHCA involving adult patients. Specifically, the data include TTI signals and automated external defibrillators (AED) analysis markers collected using Defigard Touch 7® AEDs (Schiller Medical, Wissembourg, France), as well as CPR Vvol recorded by manual ventilation monitoring devices (EOlife®, ARCHEON Medical, Besançon, France). The TTI signals and Vvol data that derived from the same OHCA can be registered. It allows better characterization of the TTI signal by identifying when TTI variations are caused by ventilations and distinguishing these from artifacts. This registration process allows to position the ventilation on TTI. The combination of TTI signals and Vvol data improves readability of CPR process, by providing a robust method to interpret TTI signals.

The apnea interval: Ventilation interruption during tracheal intubation and its association with cardiac arrest resuscitation care and outcome

BACKGROUND

Guidelines for out-of-hospital cardiac arrest (OHCA) resuscitation recommend advanced airway management without interrupting chest compressions. However, the extent and impact of interrupting ventilation is unknown. We described the apnea interval that occurs during tracheal intubation and its association with clinical outcomes.

METHODS

We conducted a cohort investigation of adult ventricular fibrillation (VF) OHCA patients who underwent attempted tracheal intubation prior to return of spontaneous circulation (ROSC) in a metropolitan EMS system (2017-2020). Apnea interval was defined as elapsed time between last breath delivered before and first breath delivered following tracheal intubation attempt. We used multivariable logistic regression to determine the relationship between apnea interval (≤60 s vs > 60 s) and outcomes: ROSC, survival to hospital discharge, and favorable neurologic survival (CPC 1-2).

RESULTS

Among 254 patients, median age was 65 years, 18% were female, and 98% had tracheal intubation success. Overall, 151 (59%) achieved ROSC, 71 (28%) survived to discharge, and 67 (26%) with favorable survival. The median apnea interval during attempted tracheal intubation was 84 s (64-113 s). Median chest compression fraction was 85% overall and 87% during the apnea interval. In unadjusted and adjusted analyses, a shorter apnea interval was associated with better outcomes: ROSC (72% vs 56%), survival (39% vs 25%), and favorable survival (39% vs 23%) (p < 0.05 for each comparison).

CONCLUSIONS

In this VF-OHCA cohort, shorter apnea intervals (≤60 s) were associated with greater likelihood of favorable outcomes. Given its variability and relationship to outcomes, the apnea interval may be a modifiable measure to improve OHCA survival.

Chest compression synchronized ventilation during prolonged experimental cardiopulmonary resuscitation improves oxygenation but may cause pneumothoraces

Background

Chest compression synchronized ventilation (CCSV) has been proposed to provide superior ventilation and haemodynamics during cardiac arrest (CA) compared to conventional asynchronous ventilation and compressions. We compared arterial gas exchange, pH, lactate levels and haemodynamics between CCSV and manual asynchronous ventilation during prolonged experimental CA.

Methods

We randomized 30 pigs (weight ca. 55 kg) to receive CCSV with a MEDUMAT Standard2 ventilator or a manual bag valve targeting 10-12 ventilations per minute. Chest compressions were provided with a Lucas® 2 device. Arterial samples were drawn every 5 min and monitoring was recorded continuously. The animals underwent chest CT scans after death.

Results

The median intra-arrest arterial blood gas results for CCSV were PaO2 = 490 (86-570) mmHg, PaCO2 = 20 (10-35) mmHg and pH = 7.39 (7.19-7.53). In the manual ventilation group, the results were PaO2 = 304 (109-379), PaCO2 = 36 (28-47) and pH = 7.24 (7.12-7.34). The oxygen levels were significantly higher in the CCSV group compared to a linear mixed model (p = 0.046). The differences in CO2 and pH levels were not statistically significant. The minute volumes and positive end-expiratory pressures were higher in the CCSV (18.0 [15.3-19.8] l/min; 32.6 [29.2-35.6] cmH2O) group compared to the control group (5.7 [4.9-7.0] l/min; 2.8 [1.8-4.1] cmH2O). The CCSV group had 12 pneumothoraces compared to 3 in the control group (p = 0.008).

Conclusions

The CCSV protocol resulted in higher arterial oxygenation but more pneumothoraces.The study was approved by the Finnish National Animal Experiment Board (ESAVI-26974-2023).

Towards a common terminology of ventilation during cardiopulmonary resuscitation

Manual and mechanical ventilation during cardiopulmonary resuscitation are critical yet poorly understood components of resuscitation care. In recent years, intra-arrest ventilation has been the subject of a growing number of laboratory and clinical investigations. Essential components to accurately interpret or reproduce original investigations are the exact measurement and transparent reporting of key ventilation parameters, such as volumes and airway pressures obtained during ongoing cardiopulmonary resuscitation. Chest compressions lead to frequent intrathoracic and intrapulmonary pressure rises which interact with artificial ventilation. The resulting unique phenomena during continuous chest compressions with asynchronous ventilation and an advanced airway necessitate a nuanced conceptualization supported by a common terminology. Based on previous original investigations and observations, we describe intra-arrest ventilation parameters and propose a common terminology integrating established and novel concepts. The proposed terminology may serve as a methodological and reporting consideration for future research of intra-arrest ventilation. Additionally, it may serve as a foundation for an authoritative scientific consensus process, which may further facilitate the transparent reporting and reproducible science needed to understand cardiopulmonary resuscitation and improve survival for cardiac arrest patients.

2024 American Heart Association and American Academy of Pediatrics Focused Update on Special Circumstances: Resuscitation Following Drowning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

Drowning is the third leading cause of death from unintentional injury worldwide, accounting for 7% of all injury-related deaths. The World Health Organization estimates that there are ≈236 000 deaths due to drowning worldwide each year. Significant efforts have focused on creating systems to prevent drowning, but an average of 4000 fatal and 8000 nonfatal drownings still occur annually in the United States-likely an underestimate. Drowning generally progresses from initial respiratory arrest due to submersion-related hypoxia to cardiac arrest; thus, it can be challenging to distinguish respiratory arrest from cardiac arrest because pulses are difficult to accurately palpate within the recommended 10-second window. Therefore, resuscitation from cardiac arrest attributable to this specific circumstance must focus on restoring breathing as much as it does circulation. Resuscitation from drowning may begin with in-water rescue breathing when safely provided by rescuers trained in the technique and should continue with chest compressions, in keeping with basic life support guidelines, once the drowned individual and the rescuer are in a safe environment (eg, dry land, a boat). This focused update incorporates systematic reviews from 2021 to 2023 performed by the International Liaison Committee on Resuscitation related to the resuscitation of drowning. These clinical guidelines are the product of a committee of experts representing the American Heart Association and the American Academy of Pediatrics. The writing group reviewed the recent International Liaison Committee on Resuscitation systematic reviews, including updated literature searches, prior guidelines related to resuscitation from cardiac arrest following drowning, and other drowning-related publications from the American Heart Association and American Academy of Pediatrics. The writing group used these reviews to update its recommendations aimed at resuscitation of cardiac arrest following drowning in adults and children.

The Association of Time to Key Prehospital Interventions Recorded by EMT-Worn video Devices and Sustained Return of Spontaneous Circulation in Out-of-Hospital Cardiac Arrest

OBJECTIVES

The quality of prehospital resuscitation provided by emergency medical technicians (EMTs) is essential to ensure better outcomes following out-of-hospital cardiac arrests (OHCA). We assessed the quality of prehospital resuscitation by recording time to key prehospital interventions using EMT-worn video devices and investigated its association with outcomes of patients with OHCA.

METHODS

This retrospective, cross-sectional study included cases of non-traumatic OHCA in adults treated by emergency medical services (EMS) in Hsinchu City, Taiwan, during 2022 and 2023. We used data from high-resolution, chest-mounted wearable cameras to define and measure six quality indices (QIs) for prehospital resuscitation interventions (i.e., time spent recognizing OHCA). To evaluate the association between QI performance and sustained return of spontaneous circulation (ROSC), we used multivariable logistic regression.

RESULTS

Of 745 patients eligible for this study, 187 (25.1%) achieved sustained ROSC. Six core QIs were analyzed: recognition of OHCA (median time: 9.0 s), time from recognizing OHCA to initiating cardiopulmonary resuscitation (cardiopulmonary resuscitation [CPR]; 9.0 s), automated external defibrillator setup (34.0 s), time from recognizing OHCA to beginning ventilation (160.0 s), advanced airway management (300 s), and deploying a mechanical CPR device (50 s). The performance of the six QIs were not associated with sustained ROSC (Adjusted odds ratio [95% confidence interval]: 1.00 [0.99-1.00], 0.99 [0.98-1.00], 1.00 [1.00-1.01], 1.00 [1.00-1.00], 1.00 [1.00-1.00], and 0.99 [0.99-1.00], respectively).

CONCLUSIONS

This study describes the rate of sustained ROSC and time to key interventions captured by EMT-worn video devices in non-traumatic OHCA patients. Although we found no direct link between QI performance and improved OHCA outcomes, this study highlights the potential of video-assisted QIs to enhance the documentation and understanding of prehospital resuscitation processes. These findings suggest that further refinement and application of these QIs could support more effective resuscitation strategies and training programs.

The impact of real-time feedback on ventilation quality during out-of-hospital cardiac arrest: A before-and-after study

INTRODUCTION

Ventilations are a critical component of cardiopulmonary resuscitation (CPR). There is conflicting evidence, however, on the most appropriate method of ventilation during cardiac arrest management. Recent evidence has suggested that regardless of the optimal ventilation strategy, ventilations are often not delivered compliant with guideline recommendations. Recent technological advancements have allowed for accurate measurement and real-time feedback of ventilation rate and volume during resuscitation. Simulation studies have found significant improvements in ventilations with the use of real-time feedback during simulated cardiac arrest. The use of feedback has not been studied in clinical practice. The objective of this study was to determine whether the use of real-time feedback improves compliance with pre-defined targets for ventilation rate and volume during out-of-hospital cardiac resuscitation.

METHODS

This was a before-and-after study with four paramedic services in Ontario, Canada. We enrolled adult, out-of-hospital cardiac arrest (OHCA) patients where the ZOLL Accuvent® device was utilized to measure ventilation rate and volume. In the before phase (without feedback), the Accuvent® was used to measure ventilations, however, providers were blinded to the real-time feedback. In the after phase (with feedback), the feedback dashboard was activated and providers used the real-time feedback to guide their ventilations. All other aspects of resuscitation remained consistent throughout the study. The main objective of the study was to compare the proportion of each case that was compliant with pre-defined ventilation targets with real-time feedback and without real-time feedback. We also examined the use of advanced airways on ventilation quality and examined for associations between ventilation parameters and return of circulation.

RESULTS

We enrolled 412 patients in the study (191 in the before phase without feedback and 221 in the after phase with feedback). Overall, we found significant improvements in both ventilation rate and volume in the after phase (with real-time feedback) compared to the before phase (without real-time feedback). We did not find any differences in ventilation compliance with or without advanced airways, or intra-arrest or post-cardiac arrest.

CONCLUSION

The use of real-time feedback was associated with an increased proportion of ventilations that were compliant with pre-defined targets during cardiac resuscitation. Further work is required to improve the use of real-time ventilation feedback, and to determine the impact of ventilations on patient outcomes.

Novel Pharyngeal Oxygen Delivery Device Provides Superior Oxygenation during Simulated Cardiopulmonary Resuscitation

INTRODUCTION

Passive oxygenation with non-rebreather face mask (NRFM) has been used during cardiac arrest as an alternative to positive pressure ventilation (PPV) with bag-valve-mask (BVM) to minimize chest compression disruptions. A dual-channel pharyngeal oxygen delivery device (PODD) was created to open obstructed upper airways and provide oxygen at the glottic opening. It was hypothesized for this study that the PODD can deliver oxygen as efficiently as BVM or NRFM and oropharyngeal airway (OPA) in a cardiopulmonary resuscitation (CPR) manikin model.

METHODS

Oxygen concentration was measured in test lungs within a resuscitation manikin. These lungs were modified to mimic physiologic volumes, expansion, collapse, and recoil. Automated compressions were administered. Five trials were performed for each of five arms: (1) CPR with 30:2 compression-to-ventilation ratio using BVM with 15 liters per minute (LPM) oxygen; continuous compressions with passive oxygenation using (2) NRFM and OPA with 15 LPM oxygen, (3) PODD with 10 LPM oxygen, (4) PODD with 15 LPM oxygen; and (5) control arm with compressions only.

RESULTS

Mean peak oxygen concentrations were: (1) 30:2 CPR with BVM 49.3% (SD = 2.6%); (2) NRFM 47.7% (SD = 0.2%); (3) PODD with 10 LPM oxygen 52.3% (SD = 0.4%); (4) PODD with 15 LPM oxygen 62.7% (SD = 0.3%); and (5) control 21% (SD = 0%). Oxygen concentrations rose rapidly and remained steady with passive oxygenation, unlike 30:2 CPR with BVM, which rose after each ventilation and decreased until the next ventilation cycle (sawtooth pattern, mean concentration 40% [SD = 3%]).

CONCLUSIONS

Continuous compressions and passive oxygenation with the PODD resulted in higher lung oxygen concentrations than NRFM and BVM while minimizing CPR interruptions in a manikin model.

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.

Increasing ventilation in drowning resuscitation - A cross-over randomized simulation study of ventilation during automated external defibrillator analysis pauses

Objective

The aim of this study was to analyze the feasibility of a new resuscitation strategy in which breaths are provided during automated external defibrillator (AED) rhythm analysis, and to evaluate its impact on chest compressions (CC) quality and the peri-analysis time.

Method

A randomized simulation study, comparing two cardiopulmonary resuscitations strategies, has been conducted: the standard strategy (S1) with strategy involving ventilation during AED analysis (S2). Thirty lifeguards have performed both strategies in a cross-over study design during 10 min of CPR.

Results

The number of ventilations per 10 min increases from 47 (S1) to 72 (S2) (p < 0.001). This results in the delivery of an additional 17.1 L of insufflated air in S2 compared to S1 (p < 0.001). There have been no significant changes in frequency and total number of CC. These findings correspond to a reduction of the non-ventilation period from 176 s (S1) to 48 s (S2).

Conclusions

This simulation study suggests that it is feasible to increase the number of ventilations during resuscitation following drowning, without affecting the quantity and quality of chest compressions. The results of this study may serve as a foundation for further investigation into optimal ventilation strategies in this context.

A new physiological manikin to test and compare ventilation devices during cardiopulmonary resuscitation

Background

There is a lack of bench systems permitting to evaluate ventilation devices in the specific context of cardiac arrest.

Objectives

The objective of the study is to assess if a new physiological manikin may permit to evaluate the performances of medical devices dedicated to ventilation during cardiopulmonary resuscitation (CPR).

Methods

Specific CPR-related features required to reproduce realistic ventilation were implemented into the SAM (Sarthe Anjou Mayenne) manikin. In the first place, the manikin ability to mimic ventilation during CPR was assessed and compared to real-life tracings of airway pressure, flow and capnogram from three out of hospital cardiac arrest (OHCA) patients. In addition, to illustrate the interest of this manikin, ventilation was evaluated during mechanical continuous chest compressions with two devices dedicated to CPR: the Boussignac cardiac arrest device (B-card - Vygon; Ecouen France) and the Impedance Threshold Device (ITD - Zoll; Chelmsford, MA).

Results

The SAM manikin enabled precise replication of ventilation tracings as observed in three OHCA patients during CPR, and it allowed for comparison between two distinct ventilation devices. B-card generated a mean, maximum and minimum intrathoracic pressure of 6.3 (±0.1) cmH2O, 18.9 (±1.1) cmH2O and -0.3 (±0.2) cmH2O respectively; while ITD generated a mean, maximum and minimum intrathoracic pressure of -1.6 (±0.0) cmH2O, 5.7 (±0.1) cmH2O and -4.8 (±0.1) cmH2O respectively during CPR. B-card allowed to increase passive ventilation compared to the ITD which resulted in a dramatic limitation of passive ventilation.

Conclusion

The SAM manikin is an innovative model integrating specific physiological features that permit to accurately evaluate and compare ventilation devices during CPR.

Recovery of arterial blood pressure after chest compression pauses in patients with out-of-hospital cardiac arrest

BACKGROUND AND AIMS

Chest compressions generating good perfusion during cardiopulmonary resuscitation (CPR) in cardiac arrest patients are critical for positive patient outcomes. Conventional wisdom advises minimizing compression pauses because several compressions are required to recover arterial blood pressure (ABP) back to pre-pause values. Our study examines how compression pauses influence ABP recovery post-pause in out-of-hospital cardiac arrest.

METHODS

We analyzed data from a subset of a prospective, randomized LUCAS 2 Active Decompression trial. Patients were treated by an anesthesiologist-staffed rapid response car program in Oslo, Norway (2015-2017) with mechanical chest compressions using the LUCAS device at 102 compressions/min. Patients with an ABP signal during CPR and at least one compression pause >2 sec were included. Arterial cannulation, compression pauses, and ECG during the pause were verified by physician review of patient records and physiological signals. Pauses were excluded if return of spontaneous circulation occurred during the pause (pressure pulses associated with ECG complexes). Compression, mean, and decompression ABP for 10 compressions before/after each pause and the mean ABP during the pause were measured with custom MATLAB code. The relationship between pause duration and ABP recovery was investigated using linear regression.

RESULTS

We included 56 patients with a total of 271 pauses (pause duration: median = 11 sec, Q1 = 7 sec, Q3 = 18 sec). Mean ABP dropped from 53 ± 10 mmHg for the last pre-pause compression to 33 ± 7 mmHg during the pause. Compression and mean ABP recovered to >90% of pre-pause pressure within 2 compressions, or 1.7 sec. Pause duration did not affect the recovery of ABP post-pause (R2: 0.05, 0.03, 0.01 for compression, mean, and decompression ABP, respectively).

CONCLUSIONS

ABP generated by mechanical CPR recovered quickly after pauses. Recovery of ABP after a pause was independent of pause duration.

Chest Decompressions - The Driver of CPR Efficacy: Exploring the Relationship Between Compression Rate, Depth, Recoil Velocity, and End-Tidal CO2

OBJECTIVE

Cardiopulmonary arrest survival is dependent on optimization of perfusion via high quality cardiopulmonary resuscitation (CPR), defined by a complex dynamic between rate, depth, and recoil velocity. Here we explore the interaction between these metrics and create a model that explores the impact of these variables on compression efficacy.

METHODS

This study was performed in a large urban/suburban fire-based emergency medical services (EMS) system over a nine-month period from 2019 to 2020. Manual chest compression parameters [rate/depth/recoil velocity] from a cohort of out-of-hospital cardiac arrest (OOHCA) victims were abstracted from monitor defibrillators (ZOLL X-series) and end-tidal carbon dioxide (ETCO2) from sensors. The mean values of these parameters were modeled against each other using multiple regression and structural equation modeling with ETCO2 as a dependent variable.

RESULTS

Data from a total of 335 patients were analyzed. Strong linear relationships were observed between compression depth/recoil velocity (r = .87, p < .001), ETCO2/depth (r = .23, p < .001) and ETCO2/recoil velocity (r = .61, p < .001). Parabolic relationships were observed between rate/depth (r = .39, p < .001), rate/recoil velocity (r = .26, p < .001), and ETCO2/rate (r = .20, p = .003). Rate, depth, and recoil velocity were modeled as independent variables and ETCO2 as a dependent variable with excellence model performance suggesting the primary driver of stroke volume to be recoil velocity rather than compression depth.

CONCLUSIONS

We used manual CPR metrics from out of hospital cardiac arrests to model the relationship between CPR metrics. These results consistently support the importance of chest recoil on CPR hemodynamics, suggesting that guidelines for optimal CPR should emphasize the importance of maximum chest recoil.

Ventilation during cardiopulmonary resuscitation with mechanical chest compressions: How often are two insufflations being given during the 3-second ventilation pauses?

BACKGROUND

Mechanical chest compression devices in 30:2 mode provide 3-second pauses to allow for two insufflations. We aimed to determine how often two insufflations are provided in these ventilation pauses, in order to assess if prehospital providers are able to ventilate out-of-hospital cardiac arrest (OHCA) patients successfully during mechanical chest compressions.

METHODS

Data from OHCA cases of the regional ambulance service of Utrecht, The Netherlands, were prospectively collected in the UTrecht studygroup for OPtimal registry of cardIAc arrest database (UTOPIA). Compression pauses and insufflations were visualized on thoracic impedance and waveform capnography signals recorded by manual defibrillators. Ventilation pauses were analyzed for number of insufflations, duration of the subintervals of the ventilation cycles, and ratio of successfully providing two insufflations over the course of the resuscitation. Generalized linear mixed effects models were used to accurately estimate proportions and means.

RESULTS

In 250 cases, 8473 ventilation pauses were identified, of which 4305 (51%) included two insufflations. When corrected for non-independence of the data across repeated measures within the same subjects with a mixed effects analysis, two insufflations were successfully provided in 45% of ventilation pauses (95% CI: 40-50%). In 19% (95% CI: 16-22%) none were given.

CONCLUSION

Providing two insufflations during pauses in mechanical chest compressions is mostly unsuccessful. We recommend developing strategies to improve giving insufflations when using mechanical chest compression devices. Increasing the pause duration might help to improve insufflation success.

A retrospective comparison of mechanical cardio-pulmonary ventilation and manual bag valve ventilation in non-traumatic out-of-hospital cardiac arrests: A study from the Belgian cardiac arrest registry

BACKGROUND

The optimal ventilation modalities to manage out-of-hospital cardiac arrest (OHCA) remain debated. A specific pressure mode called cardio-pulmonary ventilation (CPV) may be used instead of manual bag ventilation (MBV). We sought to analyse the association between mechanical CPV and return of spontaneous circulation (ROSC) in non-traumatic OHCA.

METHODS

MBV and CPV were retrospectively identified in patients with non-traumatic OHCA from the Belgian Cardiac Arrest Registry. We used a two-level mixed-effects multivariable logistic regression analysis to determine the association between the ventilation modalities and outcomes. The primary and secondary study criteria were ROSC and survival with a Cerebral Performance Category (CPC) score of 1 or 2 at 30 days. Age, sex, initial rhythm, no-flow duration, low-flow duration, OHCA location, use of a mechanical chest compression device and Rankin status before arrest were used as covariables.

RESULTS

Between January 2017 and December 2021, 2566 patients with OHCA who fulfilled the inclusion criteria were included. 298 (11.6%) patients were mechanically ventilated with CPV whereas 2268 were manually ventilated. The use of CPV was associated with greater probability of ROSC both in the unadjusted (odds ratio: 1.28, 95% confidence interval [CI]: 1.01-1.63; p = 0.043) and adjusted analyses (adjusted odds ratio [aOR]: 2.16, 95%CI 1.37-3.41; p = 0.001) but not with a lower CPC score (aOR: 1.44, 95%CI 0.72-2.89; p = 0.31).

CONCLUSIONS

Compared with MBV, CPV was associated with an increased risk of ROSC but not with improved an CPC score in patients with OHCA. Prospective randomised trials are needed to challenge these results.

Could CPAP Devices Be Used to Ventilate Cardiac Arrest Patients? A Bench Study

OBJECTIVES

To investigate the potential efficacy of a commercial continuous positive airway pressure (CPAP) ventilator to provide effective respiratory support in a simulated scenario of out-of-hospital cardiac arrest (OHCA).

METHODS

The study was conducted on a high-fidelity manikin (SimMan 3 GTM, Laerdal, NOR) connected to the ASL 5000TM Lung Simulator (IngMar Medical, USA). To simulate OHCA, we set no spontaneous respiratory acts and physiological respiratory system resistance (13 cmH2O/L.sec) and compliance (50 mL/cmH2O). The Respironics BiPAP A40 ventilatorI (Philips, NL) was used to provide ventilatory support while operating in CPAP mode. Tests were performed at different values of positive pressure of the CPAP ventilator (PCPAP: 5, 7.5, 10, 12.5 and 15 cmH2O) and the intrapulmonary volume (tidal volume, Vt) measured via the simulator software computer interface. A trained physician performed the tests. Our primary outcome was a VT of ≈500-600 mL with an intermittent maneuver simulating cardiopulmonary resuscitation (CPR)-like ventilatory support practice according to international guideline-based target (1-sec ventilation followed by 1-sec pause).

RESULTS

In intermittent ventilatory support tests, PCPAP levels of 12.5, and 15 cmH2O resulted in a VT equal to 508 ± 13 mL, and 557 ± 44 mL respectively (p = 0.04), thus approaching the VT target.

CONCLUSIONS

We provide preliminary evidence of the potential efficacy of CPAP ventilators designed for home use to provide effective respiratory support to a simulated respiratory arrest patient.