Specialty education in Colorado Springs Saving American Hearts, Inc Education events in Colorado official Colorado vacation information

Posted by Elsevier Science Direct Journals and Books October 23, 2023 on Oct 23rd 2023

Association of small adult ventilation bags with return of spontaneous circulation in out of hospital cardiac arrest

Association of small adult ventilation bags with return of spontaneous circulation in out of hospital cardiac arrest

Introduction

Little is known about the impact of tidal volumes delivered by emergency medical services (EMS) to adult patients with out-of-hospital cardiac arrest (OHCA). A large urban EMS system changed from standard adult ventilation bags to small adult bags. We hypothesized that the incidence of return of spontaneous circulation (ROSC) at the end of EMS care would increase after this change.

Methods

We performed a retrospective analysis evaluating adults treated with advanced airway placement for nontraumatic OHCA between January 1, 2015 and December 31, 2021. We compared rates of ROSC, ventilation rate, and mean end tidal carbon dioxide (ETCO2) by minute before and after the smaller ventilation bag implementation using linear and logistic regression.

Results

Of the 1,994 patients included, 1,331 (67%) were treated with a small adult bag. ROSC at the end of EMS care was lower in the small bag cohort than the large bag cohort, 33% vs 40% (p = 0.003). After adjustment, small bag use was associated with lower odds of ROSC at the end of EMS care [OR 0.74, 95% CI 0.61 – 0.91]. Ventilation rates did not differ between cohorts. ETCO2 values were lower in the large bag cohort (33.2 ± 17.2 mmHg vs. 36.9 ± 19.2 mmHg, p < 0.01).

Conclusion

Use of a small adult bag during OHCA was associated with lower odds of ROSC at the end of EMS care. The effects on acid base status, hemodynamics, and delivered minute ventilation remain unclear and warrant additional study.

Introduction

More than 350,000 Americans experience out-of-hospital cardiac arrest (OHCA) annually. With a mortality rate around 90%, identifying modifiable factors that could improve survival is a primary focus of many healthcare systems.1 While there has been significant emphasis on optimizing compressions, little is known about how best to deliver supportive ventilation during cardiopulmonary resuscitation (CPR). Excess minute ventilation can adversely affect hemodynamics in OHCA by increasing intrathoracic pressure, decreasing venous return, and negatively impacting cardiac output.2, 3, 4 Since carbon dioxide (CO2) is a major regulator of cerebral blood flow, hyperventilation causes cerebral vasoconstriction and can worsen secondary brain injury.5, 6, 7, 8 Additionally, nearly half of all OHCA patients who survive to 48 hours develop acute respiratory distress syndrome (ARDS), which can be worsened by large tidal volumes.9 Conversely, hypoventilation could produce atelectasis, worsen hypoxia, and worsen acidosis.

International guidelines recommend adults be ventilated with tidal volumes of 500–600 ml per breath during ongoing CPR, though these estimates are largely extrapolated from animal studies and healthy controls.10, 11, 12 EMS systems commonly provide rescue breaths to adults with large adult ventilation bag devices (large bags).13 Depending on manufacturer and model, large bags have maximum tidal volumes of 1500–1685 ml and deliver approximately 600–830 ml per one-handed squeeze.14, 15, 16, 17 Simulation-based studies indicate EMS providers often provide minute ventilation well above the recommended ranges to OHCA patients.18, 19

To mitigate the perceived risk of hyperventilation, the Seattle Fire Department (SFD) replaced its large bags with small adult ventilation bag devices (small bags) in the summer of 2017. The small bag reduced the maximum volume from 1685 to 1000 ml and expected delivered tidal volume from 700 to 450 ml.17 The delivered tidal volumes of the small bags more closely approximated tidal volumes used in patients receiving mechanical ventilation and known to be safe in patients with acute respiratory failure.20 The primary aim of this study was to assess the relationship between small bag use and incidence of return of spontaneous circulation (ROSC) in OHCA. We hypothesized the incidence of ROSC at the end of EMS care would increase after this change due to the potentially favorable hemodynamic effects of lower minute ventilation.

Section snippets

Study design and setting

This is a retrospective, observational cohort analysis of prospectively acquired OHCA and advanced airway management registries managed by our quality improvement staff. The Seattle Fire Department is the primary responding 911 EMS provider in Seattle, WA. The tiered response model used has been previously described.21 This study was approved by the University of Washington Institutional Review Board and adhered to STROBE guidelines for reporting observational studies.22

Emergency medical

Participants/descriptive data

From January 1, 2015 to December 31, 2021, 1,994 of 3,252 patients treated by SFD for non-traumatic OHCA met inclusion criteria (Fig. 1). The included cases totaled 48,603 minutes of resuscitation; but 15,701 (32.3%) were recorded while the patient had spontaneous circulation and were excluded from this analysis. Following exclusions, 280,107 unique ventilations were analyzed within 9,135 and 17,786 minutes of data for the large bag and small bag cohorts, respectively.Fig 2.

Across both cohorts,

Discussion

Among patients with non-traumatic OHCA who received an intra-arrest advanced airway, small bag use was associated with lower odds of ROSC at the end of EMS care. This result was unexpected since we implemented the smaller adult size ventilation bag to reduce delivery of excessive tidal volume and avoid complications related to hyperventilation. EMS providers in our study delivered a mean ventilation rate of 12 breaths/min and delivered ventilations between 9 and 11 breaths/min, close to the

Conclusion

In conclusion, the use of small adult ventilation bags was associated with a lower likelihood of ROSC at the end of EMS care in non-traumatic, adult OHCA. Future studies should measure the relationship between tidal volume delivered and patient outcomes, as well as impact on downstream lung injury.

CRediT authorship contribution statement

Bonnie D. Snyder: . Molly R. Van Dyke: Writing – review & editing, Software, Formal analysis, Data curation. Robert G. Walker: Writing – review & editing, Software, Resources. Andrew J. Latimer: Writing – review & editing, Conceptualization. Bartholomew C. Grabman: Writing – review & editing, Conceptualization. Charles Maynard: Writing – review & editing, Validation, Methodology, Formal analysis. Thomas D. Rea: Writing – review & editing, Validation. Nicholas J. Johnson: Writing – review &

Declaration of competing interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: This research did not receive any external funding. Robert Walker is a biomedical engineer employed by Stryker Emergency Care. Nicholas Johnson receives research funding from National Institutes of Health, Centers for Disease Control and Prevention, and University of Washington Royalty Research Fund for unrelated work and serves on a Scientific Advisory Board

Acknowledgements

Thanks to the paramedics, EMTs, dispatchers, and staff of the Seattle Fire Department for their commitment to and delivery of excellent patient care.

References (39)

Newsletter Signup