Real-time transesophageal echocardiography for guiding prolonged cardiopulmonary resuscitation

Prolonged cardiopulmonary resuscitation (CPR) often presents a dilemma regarding when to terminate resuscitation efforts, particularly when the return of spontaneous circulation (ROSC) remains elusive. Transesophageal echocardiography (TEE) has emerged as a valuable tool for real-time hemodynamic monitoring during CPR, but its role in guiding extended resuscitation beyond conventional time limits has not been reported. We present a case in which real-time TEE assessment of myocardial viability supported the decision to continue CPR for 90 min,ultimately resulting in successful resuscitation without neurological sequelae.

A 70-year-old male experienced ventricular fibrillation (VF) and loss of consciousness during a routine echocardiographic examination. Immediate chest compressions were initiated, and the patient was transferred to the emergency department (ED) at 10:45 am (day 1).

Upon arrival, the patient was comatose with bilaterally dilated and non-reactive pupils. The emergency physicians immediately initiated chest compressions and bag-valve-mask ventilation, followed by endotracheal intubation. Mechanical ventilation was subsequently established using volume-controlled ventilation (VCV) with the following settings: fraction of inspired oxygen (FiO₂) 100%, tidal volume (Vₜ) 460 mL, positive end-expiratory pressure (PEEP) 3 cmH₂O (1 cmH₂O=0.098 kPa), and respiratory rate 10 breaths/min. Intravenous (IV) access was rapidly established, and epinephrine was administered every 3 min at a dosage of 1 mg.

The initial rhythm analysis at 10:48 am revealed VF. Immediate unsynchronized biphasic defibrillation at 200 J was performed, with subsequent uninterrupted manual chest compressions and scheduled rhythm checks every 2 min. At 10:52 am, recurrent VF was detected, prompting a second defibrillation and continued compressions. Amiodarone (300 mg) was administered as an IV bolus. Two additional VF episodes occurred at 11:00 am and 11:05 am, when the patient was treated with repeated defibrillation and an additional 150 mg of amiodarone. Severe metabolic acidosis, as evidenced by initial arterial blood gas (pH 6.936, PaO₂ 76.2 mmHg [1 mmHg=0.133 kPa], PaCO₂ 50.9 mmHg, and lactate concentration 14.31 mmol/L), prompted the IV administration of 125 mL of 5% sodium bicarbonate.

Simultaneously, with ongoing CPR, TEE was performed by the emergency physician. Rapid sequential scans were conducted in the following order: midesophageal four-chamber (ME 4C) view→midesophageal two-chamber (ME 2C) view→midesophageal long-axis (ME LAX) view→upper esophageal aortic arch short-axis (UE aortic arch SAX) view→descending aorta short-axis (descending aorta SAX) view. This examination excluded structural causes of cardiac arrest, including pulmonary embolism, aortic dissection, cardiac tamponade, and cardiac rupture. Simultaneously, TEE guidance was utilized to optimize manual chest compression positioning, ensuring maximal ventricular compression while avoiding left ventricular outflow tract (LVOT) obstruction.

After approximately 30 min of CPR, the patient demonstrated no improvement in neurological status (unchanged consciousness and fixed pupils), unobtainable blood pressure, or an absent carotid pulse. Rhythm analysis showed a slow idioventricular rhythm without signs of ROSC. By conventional criteria, termination of resuscitation would have been considered at this juncture. However, TEE revealed visible yet ineffective myocardial contractions consistent with electromechanical dissociation (manifesting as pseudopulseless electrical activity [pseudo-PEA]); contractile activity was present but insufficient in amplitude and frequency to maintain systemic perfusion (supplementary video 1). These findings indicated preserved myocardial viability with the potential for ROSC. Based on these TEE results, the resuscitation team continued manual chest compressions.

Continuous TEE monitoring was maintained to assess myocardial contractile efficacy (supplementary video 2). Gradual recovery of myocardial function was observed as resuscitation progressed. Following approximately 60 min of additional CPR (approximately 12:15 pm), TEE demonstrated that the heart had resumed stable, rhythmic contractions, with myocardial activity transitioning from ineffective to effective contractions, thereby achieving sustained ROSC (supplementary video 3). A subsequent comprehensive TEE examination was performed in the following sequence: ME 4C view→ ME 2C view→ME LAX view→ transgastric short-axis (TG SAX) view. This revealed markedly reduced motion/severe hypokinesis of the left ventricular anterior wall (Figure 1) (supplementary video 4). Subsequent 12-lead electrocardiography demonstrated ST-segment elevation in the precordial leads, confirming the diagnosis of acute anterior myocardial infarction (Figure 2).

Figure 1. The midesophageal two-chamber view demonstrating akinesia of the extensive anterior wall after ROSC (arrows).

Figure 2. The 12-lead electrocardiogram obtained after ROSC, showing significant ST-segment elevation in the anterior leads. ROSC: return of spontaneous circulation.

Emergency coronary angiography at 12:35 pm (day 1) revealed total occlusion of the left anterior descending artery (LAD) ostium (Figure 3). Successful revascularization was achieved via balloon angioplasty and stent implantation.

Figure 3. Emergency coronary angiography and percutaneous intervention for the LAD. A: initial angiography reveals total occlusion at the ostium of the LAD (arrow), with a TIMI flow grade of 0; B: post-interventional angiography after balloon angioplasty and implantation of a 3.5 mm×13.0 mm drug-eluting stent showing restoration of TIMI flow grade III in the target vessel (arrow indicates the stent site). LAD: left anterior descending artery.

Following a 2-week hospitalization, the patient was discharged on day 14 and was fully ambulatory and neurologically intact. At the one-year follow-up, he remained asymptomatic without recurrent myocardial infarction or TEE-related complications.

This case demonstrates the pivotal role of real-time TEE in resuscitation decision-making, especially during prolonged CPR. Current resuscitation guidelines typically consider termination of CPR after 30 min of advanced life support without ROSC, particularly when clinical signs such as non-measurable blood pressure, fixed pupils, and an absent carotid pulse indicate refractory cardiac arrest.^[1,2] However, these traditional clinical parameters often fail to reflect true myocardial status. A previous study has demonstrated that 10%-35% of patients with electrocardiographic asystole or PEA actually maintain sonographic cardiac activity when assessed by echocardiography.^[3] In the present case, despite the absence of palpable pulses and non-measurable arterial pressure after 30 min of CPR—findings that would typically prompt consideration of resuscitation termination—TEE revealed preserved myocardial contractility characterized by electromechanical dissociation (pseudo-PEA). This critical difference between clinical assessment and ultrasonographic findings underscores the inherent limitation of peripheral perfusion markers in reflecting intrinsic cardiac function during prolonged CPR.^[4]

The utility of intra-arrest TEE has been increasingly recognized in recent years. A systematic review by Vetrugno et al^[5] revealed that TEE identifies the etiology of cardiac arrest in up to 43% of cases (compared with 13% with transthoracic echocardiography [TTE]) and influences clinical decision-making in approximately 78% of resuscitation scenarios. Teran et al^[6] reported that TEE detected pseudo-PEA in 28% of patients with apparent PEA, revealing coordinated ventricular contractions that were insufficient to generate systemic perfusion. Similarly, Hwang et al^[7] utilized TEE and demonstrated that conventional chest compressions resulted in LVOT obstruction or aortic root compression in 41% of cases, with stroke volume correlating significantly with compression position.

Our case extends these findings by providing the first detailed visualization of the dynamic transition from ineffective to effective myocardial contractions during ultra-prolonged CPR. While a previous report documented TEE identification of reversible causes or optimization of compression mechanics,^[8] the present case uniquely demonstrates TEE’s ability to monitor the temporal evolution of myocardial contractility over 90 min of resuscitation. The observed progression from electromechanical dissociation to coordinated ventricular contractions with systemic perfusion capability offers direct visual evidence supporting the rationale for prolonged resuscitation when TEE indicates preserved myocardial viability.

Currently, TEE-assisted CPR remains largely dependent on operator experience and qualitative visual assessment. Our case highlights the urgent need for quantitative metrics to standardize the evaluation of myocardial contractile effectiveness during resuscitation. Future research should focus on developing reproducible TEE parameters—such as left ventricular fractional area change, aortic valve opening duration, or Doppler-derived flow velocities—to objectively assess compression efficacy and predict ROSC potential. Additionally, structured training protocols enabling emergency physicians to perform focused resuscitative TEE examinations within 7-12 min of patient arrival have proven feasible and safe, supporting broader implementation of this technology in emergency departments.^[6]

End-tidal carbon dioxide (ETCO₂) measurement represents the only hemodynamic monitoring parameter with established prognostic value during CPR, with levels ≥20 mmHg after 20 min serving as a robust predictor of ROSC, whereas an ETCO₂ <10 mmHg after 20 min is associated with a ROSC probability of merely 0.5%.^[9] Unfortunately, the absence of capnography in our resuscitation center precluded comparisons between TEE-derived myocardial contractility and this quantitative physiologic marker. This limitation prevents us from determining whether TEE assessment of myocardial contractility could serve as a complementary or alternative prognostic indicator to ETCO₂ in predicting ROSC during prolonged CPR.

On the other hand, while ETCO₂ is currently recognized as the sole hemodynamic parameter with proven prognostic value for predicting ROSC during CPR, its utility as a peripheral circulation marker presents specific constraints in assessing real-time myocardial contractility. We posit that TEE does not conflict with but rather supplements ETCO₂ monitoring, providing clinicians with an alternative visualization modality to evaluate the effectiveness of resuscitation efforts. Future studies should prospectively evaluate the correlation between TEE-derived myocardial performance parameters (such as fractional area change or mitral annular plane systolic excursion) and ETCO₂ values to establish integrated monitoring protocols.

This case demonstrates that real-time TEE may serve as a decision-making tool during prolonged CPR, enabling the identification of salvageable myocardial activity when conventional monitoring suggests futility. Integration of TEE into resuscitation protocols raises the possibility of extending the temporal limits of effective CPR and may offer a potential for recovery in select patients. Prospective studies are warranted to validate TEE-guided resuscitation strategies and establish objective criteria for continuing versus terminating prolonged CPR efforts.

Funding: This study was supported by National Key Clinical Specialty Construction Project (2022).

Ethical approval: This study was approved by the Ethics Review Committee of Beijing Jishuitan Hospital, Capital Medical University. The ethical approval number is Ji Lun [K2024] No. [525]-01.

Conflicts of interest: The authors declare that they have no conflicts of interest.

Contributions: LXQ proposed the study and wrote the paper. All the authors contributed to the design and interpretation of the study and to further drafts.

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