Cardiopulmonary Resuscitation Without Aortic Valve Compression Increases Chances of Return of Spontaneous Circulation for Patients Experiencing Out-of-hospital Cardiac Arrest
Authors: Chu Sheng-En , Huang Chun-Yen , Cheng Chiao-Yin , Chan Chun-Hsiang , Chen Hsuan-An , Chang Chin-Ho , Tsai Kuang-Chau , Chiu Kuan-Ming , Ma Matthew Huei-Ming , Chiang Wen-Chu , Sun Jen-Tang 
Published: July 2023

Background

Current cardiopulmonary resuscitation (CPR) guidelines recommend that chest compressions should be applied at “the center of the chest.” However, in approximately 50% of patients experiencing out-of-hospital cardiac arrest (OHCA) the aortic valve (AV) is reportedly compressed, potentially obstructing blood flow and worsening prognosis. We aimed to use resuscitative transesophageal echocardiography (TEE) to elucidate the impact of compressed vs. uncompressed AV on outcomes of adult patients experiencing OHCA.

Methods

This prospective single-center observational cohort study included patients experiencing OHCA who underwent resuscitative TEE in the emergency department (ED). Exclusion criteria were early return of spontaneous circulation (ROSC) before TEE, resuscitative endovascular balloon occlusion of the aorta (REBOA) or extracorporeal membrane oxygenation (ECMO) initiation before ROSC, unidentifiable compression site, or poor quality/missing TEE images. Patients were divided into AV-compressed or uncompressed groups based on initial TEE findings. Documented patient characteristics, TEE recordings, resuscitation data, and critical time points were analyzed. Primary outcome was sustained ROSC. Secondary outcomes included end-tidal carbon dioxide (EtCO2) level at the 10th-minute post-ED arrival, any ROSC, survival to admission and discharge, active withdrawal post-resuscitation, and favorable neurological outcomes at discharge. Sample size was pre-estimated at 37 patients/group.

Results

From October 2020 to January 2023, 76 patients were enrolled (39 and 37 patients in the AV-uncompressed and compressed groups, respectively). Intergroup baseline characteristics were similar. The AV-uncompressed group had better probability of sustained ROSC (53.8% vs. 24.3%, odds ratio [OR] 3.63, adjusted OR [aOR] 4.72,P=0.010), any ROSC (56.4% vs. 32.4%, OR 2.70, aOR 3.30,P=0.033), and survival to admission (33.3% vs. 8.1%, OR 5.67, aOR 6.74,P=0.010) than the AV-compressed group. The 10th-minute EtCO2levels (16.0 vs. 14.0 mmHg), active withdrawal post-resuscitation (7.7% vs. 5.4%), and survival to discharge (5.1% vs. 0%) revealed no significant intergroup differences. No patient was discharged with favorable neurological outcomes. An uncompressed AV remained an essential factor for sustained ROSC across all predefined subgroups.

Conclusions

Uncompressed AV during CPR increases the chances of ROSC and survival to admission among patients experiencing OHCA. However, its potential impact on long-term survival and neurological outcomes remains unclear.

Clinical Trial Registration

This trial was registered at ClinicalTrials.gov, identifierNCT05932784. URL:https://clinicaltrials.gov/study/NCT05932784.

Clinical Perspective

1)

What is new?

When performing cardiopulmonary resuscitation according to the current guideline-recommended site, chest compressions may lead to accidental compression of the aortic valve (AV), which obstructs blood flow and worsens prognosis for patients experiencing out-of-hospital cardiac arrest.

We have used resuscitative transesophageal echocardiography to elucidate the impact of compressed vs. uncompressed AV on outcomes of these patients, a hitherto unexplored aspect.

Primary outcome was sustained return of spontaneous circulation (ROSC) and secondary outcomes included end-tidal carbon dioxide level at the 10th-minute post-emergency department arrival, any ROSC, survival to admission and discharge, active withdrawal post-resuscitation, and favorable neurological outcomes at discharge.

2)

What are the clinical implications?

The AV-uncompressed group had a better chance of sustained ROSC, any ROSC, and survival to admission than the AV-compressed group.

However, its potential impact on long-term survival and neurological outcomes remains unclear; if resuscitative transesophageal echocardiography can be successfully used or if more convenient and lightweight tools can detect AV compression, both in prehospital situations, stronger evidence may be obtained.

Current cardiopulmonary resuscitation guidelines may need to be revised for a more individualized approach, which can help rescuers avoid accidental AV compression and improve patient outcomes and prognosis.