Real-time identification of aetiology in patients able to undergo transoesophageal echocardiography with non-traumatic out-of-hospital cardiac arrest in China: a prospective, single-centre exploratory study

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) in China has a high incidence and poor survival, highlighting an urgent need for rapid identification of reversible aetiologies. Conventional transthoracic echocardiography during resuscitation can be limited by imaging quality and prolonged chest compression interruptions. Transoesophageal echocardiography (TEE) is a feasible alternative that allows for continuous real-time imaging during compressions, but its utility in Chinese OHCA patients remains uncertain. METHODS: This prospective, single-centre exploratory study enrolled 45 consecutive selected adults with non-traumatic OHCA (NT-OHCA) of unclear aetiology who were eligible for TEE. Of all enrolled patients, 43 completed standardised TEE image acquisition, while 2 cases with TEE-unrecognisable aetiology were excluded from aetiological analysis. The per-protocol analysis finally included 41 patients in whom TEE was successfully completed. Certified emergency physicians performed simplified TEE examinations (five standard views) during active resuscitation. Door-to-TEE interval, diagnostic yield, TEE-guided interventions and clinical outcomes were recorded according to Utstein guidelines. RESULTS: TEE yielded diagnostic-quality images in all patients (43/43), with a median door-to-TEE time of 13 min (IQR: 6.5-22). Reversible aetiologies were identified in 39.0% (16/41), most commonly acute aortic dissection (50.0%, 8/16), followed by massive pulmonary embolism (25.0%), hypertrophic cardiomyopathy (18.8%) and hypovolaemia (6.3%). TEE guided interventions in 56.3% (9/16) of identified cases. Return of spontaneous circulation (ROSC) and 28-day survival rates were 41.5% and 12.2%, respectively, with no significant differences between aetiology-identified and unidentified groups (ROSC: 37.5% vs 44.0%, p>0.05; 28-day survival: 6.3% vs 16.0%, p>0.05). Sensitivity analysis of the 43-case complete imaging cohort and the total 45 enrolled cases further verified the stability and reliability of the diagnostic results. CONCLUSIONS: During mechanical cardiopulmonary resuscitation, TEE rapidly identified suspected aetiologies in 39% (16/41) of NT-OHCA cases, notably revealing frequent acute aortic dissections. Lacking a comparator group, TEE's feasibility as a complementary tool requires further controlled investigation.