Background

Cardiac ultrasound is an established diagnostic modality in Emergency Medicine (EM). We use it to diagnose pericardial effusions (medical and traumatic), to discern the etiology of shock, to evaluate for congestive heart failure, and to guide treatment and prognosis in cardiac arrest. Nonetheless, the trans-thoracic approach (TTE) to cardiac ultrasound has its limitations: poor windows (in the trauma patient, the patient with COPD, or the obese patient), poor timing (interrupting chest compressions), and heavily user dependent. In critically ill patients, all these factors combine to make obtaining high quality TTE images that much more difficult.

Trans-esophageal echocardiography (TEE) provides an excellent alternative to TTE as it can be inserted during chest compressions, provides excellent windows with minimal manipulation, and reliably generates high quality images. Blaivas demonstrated in a groundbreaking EM case series in 2008 that TEE can help guide resuscitations during cardiac arrest and provide diagnoses that could not be reached with TTE alone. Despite these advantages, TEE has not been widely applied in Emergency Departments (EDs) almost a decade later.

Clinical Question

Is it feasible to utilize TEE in the ED and does this modality have a clinical impact on management?
Additionally, what are the complications that occur from the use of TEE in the ED?

Population

Intubated, critically ill patients (medical and traumatic) who underwent TEE in the ED in two Canadian EDs from February 1, 2013 to January 30, 2015.

Intervention

Bedside TEE in the ED following a 4 view protocol by emergency physicians

Design

Retrospective reivew

Primary Results

Primary Results:

  • 54 TEE studies were performed over 2 years by 12 Emergency physicians
  • 64% no vital signs on arrival, 72% admitted to ICU, 28% died in the ED
  • Indication for TEE was intra-arrest and post-arrest management primarily, but medical and traumatic hypotension were also included
  • 100% of patients undergoing TEE were intubated prior to the procedure
  • 100% of patients had successful placement (83% 1st pass success)
  • 98% of cases had interpretable images
  • 0% aero-digestive complications on chart review and autopsy (in available cases)

Critical Results:

The clinical impact of each TEE was divided into: (1) diagnostic influence on clinical decision-making and (2) therapeutic influence on procedures, prescription of fluids, or ceasing resuscitation based on findings.

  • 78% of patients TEE provided diagnostic influence (2 aortic dissections, 1 fine ventricular fibrillation, 4 cases of hypovolemic shock, 5 LV dysfunction, and 27 cases where they “ruled out the cause of arrest”
  • 24% TEE had no influence on the diagnosis
  • 57% they found “TEE-specific findings” (quality of CPR, fine v-fib, aortic dissection, procedural guidance) beyond “basic” echo findings
  • 67% TEE had a therapeutic influence (primarily CPR management like changing providers, moving hands, increasing depth, increasing rate).
  • 30% TEE helped make a prognostic decision as to the expected course (and stop further efforts)
  • 18% it helped guide volume and fluid management
  • 8% TEE helped guide pressors / ionotrope management
  • In one case TEE helped with trans-venous pacing guidance

Strengths

  • First paper of its kind describing a novel TEE program in an ED
  • Demonstrated that conducting TEE studies by Emergency physicians in the ED is feasible and clinically influential

Limitations

  • Small sample size of 54 cases
  • Unique experience that can be replicated by very few other EDs at this time
  • Retrospective review; not possible to compare TEE to TTE head-to-head
  • Cannot evaluate for TEE patient-centered outcomes, like 30-day mortality

Other Issues

  • No known aero-digestive complications, but in many cases where the patient died in the ED, it was not clear if there had been any aero-digestive injuries

Author's Conclusions

"From our analysis of a single-center experience, ED-based TEE showed a high degree of feasibility (98% determinate rate) and clinical utility, with a diagnostic and therapeutic influence seen in the majority of cases. Focused TEE demonstrates the most promise in patients who are intubated and have either undifferentiated shock or cardiac arrest."

Our Conclusions

Placing a TEE into critically ill and intubated patients seems feasible and without a high risk of complication. TEE can affect diagnosis and therapeutic intervention, depending on your definitions of both. If the only thing that has been shown to improve outcomes in cardiac arrest is high quality chest compressions, then TEE may be an excellent tool to help improve compressions. The benefits of placing a TEE probe in critically ill trauma and medical patients in the ED appears to outweigh the risks in skilled hands.

Potential Impact To Current Practice

In the future we expect to see a multicenter trial comparing outcomes in critically ill patients comparing the use of TTE to TEE. This studies and others like it lead us to believe that TEE has the potential to become an important part of the management of cardiac arrest and critically ill patients in the ED in the future.

Bottom Line

TEE is an emerging application in the ED as it has a number of diagnostic advantages over TTE. It is feasible for trained emergency physicians to perform TEE and it impacts both diagnosis and therapy in critically ill patients. Prospective randomized studies are needed to elucidate the role of TEE in comparison to other imaging modalities and skilled clinician evaluation.

Read More

Read More:

Ultrasound Podcast: Echo Arrest Case

Ultrasound Podcast: Bedside TEE Part 1

Ultrasound Podcast: Bedside TEE Part 2

Blaivas M. Transesophageal echocardiography during cardiopulmonary arrest in the emergency department. Resuscitation, 2008; 78, 135-140. PMID: 18486300

Arntfield RT et al. Focused transesophageal echocardiography for emergency physicians – description and results from simulation training of a structured four-view examination. Crit Ultrasound J 2015; 7:10. PMID: 26123608

Arntfield RT. An elderly woman that presents with absent vital signs. Chest, 2014; 146:e156-9. PMID: 25367482