Month: October 2017

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Focused Transesophageal Echocardiography by Emergency Physicians is Feasible and Clinically Influential

Background

Cardiac ultrasound is frequently used in the emergency department (ED) to effectively identify  pericardial effusion, differentiate causes of shock, assess left ventricular function, and guide cardiopulmonary resuscitation (CPR). However, cardiac ultrasound employed in the ED is usually transthoracic echocardiography (TTE) as opposed to transesophageal echocardiography (TEE). TTE can often be limited, especially in critically ill patients and patients with high BMI. TEE offers the ability to reliably obtain continuous high-quality images that can be performed without interrupting CPR. Despite this, TEE is not often employed in the ED due to a variety of factors, including transducer cost, invasiveness, physician training, and hospital culture.

Focused Transesophageal Echocardiography by Emergency Physicians is Feasible and Clinically Influential: Observational Results from a Novel Ultrasound Program

 

Clinical Question

Is TEE performed by emergency medicine trained  physicians, in the emergency department setting, feasible and does it provide clinical utility?

Methods & Study Design

  • Design
    • Retrospective Review
  • Population
    • Study performed during a TEE in the ED pilot program by an academic emergency medicine program comprising 2 separate EDs, one of which is a regional trauma center.
    • All patients who underwent TEE in the ED during the 2-year program period were included.
  • Exclusion criteria
    • None
  • Intervention
    • TEE was performed on critically ill, intubated patients. Most commonly, the mid-esophageal 4-chamber view, followed by the transgastric short axis, mid-esophageal long axis, and bicaval views  were obtained.
  • OutcomesThe clinical impact of TEE, divided into two categories:
      • Diagnostic influence on clinical decision making
      • Therapeutic influence on procedures, medications, fluids, and CPR

Results

    • 54 TEE exams performed with 100% probe insertion success rate
      • 83% on first attempt
      • 11% required multiple attempts
      • 6% required use of a laryngoscope
      • 98% of exams produced images that were interpretable by the operator
    • TEE was diagnostically influential in 78% of cases
      • Excluded cardiac cause of arrest (56%)
      • Identified depressed left ventricular function (15%)
      • Identified hypovolemia (13%)
      • Identified regional wall motion abnormalities (6%)
      • Identified aortic dissection (4%)
    • TEE was therapeutically influential in 67% of cases
      • Influenced changes to CPR (43%)
      • Directed cessation of resuscitation (30%)
      • Guided hemodynamic support (26%)
    • No major adverse effects from probe placement identified

Strengths & Limitations

  • Strengths
    • TEE exams were performed successfully by 14 different emergency physicians at 2 separate sites after only 4 hours of training, which demonstrated well the feasibility of TEE use in the ED on a more widespread basis.
    • Well-described outcomes
  • Limitations
    • Retrospective
    • Relatively small sample size
    • No comparison with TTE

Author's Conclusions

“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

This study demonstrates that performing TEE in the ED is both feasible and safe, and can be implemented with limited training of the physician staff. It also shows that TEE does have some clinical utility in the ED, specifically the detection of aortic dissection. However, the most common therapeutic effect noted in the study was the assessment of CPR quality, which can typically be assessed with less invasive means such as femoral pulse palpation and waveform capnography. The other common findings noted in the study (i.e. depressed ejection fraction, hypovolemia, guidance of hemodynamic support) can typically be assessed with more traditional and less invasive TTE. In order to truly evaluate the utility of TEE in the ED, a prospective study showing a comparison of TEE with TTE, and other less invasive diagnostic modalities, would need to be performed. That being said, having the ability to diagnose aortic dissection at the bedside and to guide resuscitation via direct cardiac visualization during ongoing CPR are important considerations. This is a promising pilot study that opens up the door for further research evaluating the utility of TEE in the ED, however at this point, it is not clear whether it will perform better than traditional TTE and other clinical adjuncts in both diagnostic and therapeutic abilities.

The Bottom Line

Performing TEE in the ED is both feasible and safe, and does provide useful clinical information. However more studies are required in order to assess the true clinical utility of this modality.

Authors

This post was written by Toby Matt, MS4 at UCSD. It was reviewed by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

    1. Arntfield R, e. (2017). Focused Transesophageal Echocardiography by Emergency Physicians is Feasible and Clinically Influential: Observational Results from a Novel Ultraso... - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 30 October 2017, from https://www.ncbi.nlm.nih.gov/pubmed/26508495
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Case # 8: A Case of Comparision

A 40 year old male presents to the emergency department with pain to the entire right thumb and wrist for 1 day.  He notes that he suffered a small puncture wound to his right thumb 1 day ago while working on his car.  The patient has notable circumferential, non-erythematous swelling to his right thumb with tenderness along the flexor tendon. There is also fullness of the dorsum of his wrist. He is holding his fingers flexed and has pain radiating into the wrist with any movement of his fingers or wrist, especially with extension of his fingers.

Vitals: T 98.7 HR 90 BP 132/81  RR 13 O2 98% on RA

A bedside ultrasound is performed, what is the next best step in management?

Normal Left Thumb in Long Axis

Normal Left Thumb in Long Axis

Abnormal Right Thumb in Long Axis

Abnormal Right Thumb in Long Axis

Answer and Learning Points

Answer

Empirical antibiotic therapy and orthopedic surgery consultation for infectious flexor tenosynovitis (FTS).  The patient meets 4 out of 4 Kanavel's signs and has ultrasound evidence of FTS suggested by a thickened tendon with surrounding anechoic fluid.

Short Axis View of Right 1st Digit demonstrating hypoechoic fluid surrounding tendon.

Learning Points

    • FTS is often a clinical diagnosis and examination (Kanavel's signs) is thought to have high sensitivity (91.4-97.1%) but low specificity (51.3-69.2%) for infectious FTS [2]; however a negative exam does not rule it out completely.
      • Kanavel's signs include:
        • Finger held in slight flexion
        • Fusiform swelling
        • Tenderness along the flexor tendon sheath
        • Pain with passive extension of the digit
    • FTS is treated with empirical antibiotic  therapy as well as early surgical debridement and drainage. Delays in diagnosis can lead to local spread of infection, compartment syndrome and necrosis.
    • While there is not high quality evidence describing the use of emergency department point of care ultrasound (POCUS) to diagnose FTS, previous radiographic studies have found ultrasound to be more sensitive than clinical exam for detecting tenosynovitis [3].
    • Common ultrasound findings for FTS include:
      • Hypoechoic or anechoic edema or debris within the tendon sheath
      • +/- thickening of the tendon sheath
    • The ultrasound examination should be performed using a linear probe, examining the affected tendon (and normal tendon on other hand for comparison), in both the longitudinal and transverse plane.
      • Small rocking or fanning motions should be used to ensure perpendicular orientation of the probe to the tendon to avoid artifact secondary to anisotropy.
    • As in all uses of POCUS in the emergency department setting, findings should be interpreted in conjunction with clinical examination and history when evaluating for infectious FTS. We believe POCUS for infectious FTS can be used to increase diagnostic certainty and even expedite care and aggressive treatment however a normal exam should not be used to rule out this diagnosis.

Author

This post was written by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

    1. Padrez, K., Bress, J., Johnson, B., & Nagdev, A. (2015). Bedside Ultrasound Identification of Infectious Flexor Tenosynovitis in the Emergency Department. Western Journal Of Emergency Medicine, 16(2), 260-262. doi:10.5811/westjem.2015.1.24474
    2. Kennedy CD, e. (2017). Differentiation Between Pyogenic Flexor Tenosynovitis and Other Finger Infections. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 21 October 2017, from https://www.ncbi.nlm.nih.gov/pubmed/28720000
    3. Hmamouchi I, Bahiri R, Srifi N, et al. A comparison of ultrasound and clinical examination in the detection of flexor tenosynovitis in early arthritis. BMC Musculoskelet Disord. 2011;12(1):91.
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Variability in Interpretation of Cardiac Standstill Among Physician Sonographers

Background

The use of point-of-care echocardiography to inform termination or continuation of cardiopulmonary resuscitative efforts remains controversial [1,2]. Current understanding of its utility in prognostication is limited by varying definitions of cardiac activity. Definitions of cardiac standstill range from absence of “organized contractile activity (nonfibrillating) with a decrease in chamber size” to absence of “any visible movement of the myocardium, excluding movement of blood within the cardiac chambers or isolated valve movement” to absence of “any detected atrial, valvular, or ventricular motion within the heart” [3-5]. Without a consistent definition of cardiac standstill, it is difficult to interpret studies reporting conflicting resuscitation outcomes in cardiac arrest.

Variability in Interpretation of Cardiac Standstill Among Physician Sonographers

Clinical Question

What is the interrater reliability among providers in classification of cardiac standstill in point-of-care echocardiography?

Methods & Study Design

  • Design
    • Cross-sectional convenience sample survey
  • Population
    • Eligible: Residents, fellows, and faculty practicing in emergency medicine, critical care, or cardiology in attendance at one of six weekly emergency medicine (EM) conferences held at the following locations:
      • Icahn School of Medicine at Mount Sinai
      • Beth Israel Medical Center
      • St. Luke’s-Roosevelt Hospital
  • Exclusion criteria
    • Providers who had previously participated at a prior conference
  • Intervention
    • Participants were presented with the following clinical scenario: “55-year-old man in cardiac arrest who remains pulseless after 20 minutes of CPR”
    • Participants were shown 15 clips (6 seconds each, looped for 20 seconds total) presenting a variety of sonographic features
    • Asked to identify presence or absence of cardiac activity
    • Responses transmitted via remote polling devices
    • No definition of cardiac activity was provided
  • Outcomes
    • Primary: interrater reliability in interpreting cardiac standstill (Krippendorff’s alpha coefficient)
    • Secondary: subgroup analyses by specialty, training level, and self-described point of care (POC) ultrasound experience

Results

    • 127 participants (majority EM residents with basic ultrasound skills)
    • Overall moderate agreement with respect to identifying cardiac standstill (alpha 0.47)
    • Clips with stronger agreement:
      • No myocardial contraction
      • Myocardial contraction
      • Strong myocardial contraction
    • Clips with poorer agreement:
      • Valve flutter
      • Mechanical ventilation
      • Weak myocardial contraction
    • Moderate agreement across all training levels and self-reported ultrasonographic skill levels

Strengths & Limitations

  • Strengths
    • All participants saw the same clips
    • Response time limited (similar to clinical practice)
  • Limitations
    • Bias: recruitment from academic conferences
    • Majority with no or basic self-reported ultrasonographic skill level
    • Reported discussion among participants throughout survey

Author's Conclusions

“Our results support the possibility that previous studies have been subject to variability in the interpretation of cardiac standstill.”

Our Conclusions

We agree with the authors’ conclusions that there appears to be substantial variability in the interpretation of cardiac standstill. This study highlights a weakness in the current literature examining the utility of POC echocardiography used during resuscitation futility assessment. While this study does not provide data on clinical outcomes of standstill misclassification, it identifies a potential weakness in the available research. It is difficult to interpret studies reporting outcomes after standstill (such as meaningful survival) when the predictor is not consistently identified.

As a follow-up study, it would perhaps be interesting to see how the interrater reliability changes when participants are provided with a clear definition of cardiac standstill. Does the variability persist even with a uniform definition? If this improves interrater reliability it would provide additional support for the need for a consensus definition across future studies.

The Bottom Line

There is significant variability in classification of cardiac standstill among providers. A uniform definition of standstill may reduce this variability and aid in the interpretation of studies reporting conflicting outcomes after cardiac arrest.

Authors

This post was written by Carly Dougher, MS4 at UCSD. It was reviewed by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

    1. Blyth, L., Atkinson, P., Gadd, K. & Lang, E. Bedside Focused Echocardiography as Predictor of Survival in Cardiac Arrest Patients: A Systematic Review: Echocardiography in Cardiac Arrest. Acad. Emerg. Med. 19, 1119–1126 (2012).
    2. Cohn, B. Does the Absence of Cardiac Activity on Ultrasonography Predict Failed Resuscitation in Cardiac Arrest? Ann. Emerg. Med. 62, 180–181 (2013).
    3. Schuster, K. M. et al. Pulseless Electrical Activity, Focused Abdominal Sonography for Trauma, and Cardiac Contractile Activity as Predictors of Survival After Trauma: J. Trauma Inj. Infect. Crit. Care 67, 1154–1157 (2009).
    4. Gaspari, R. et al. Emergency department point-of-care ultrasound in out-of-hospital and in-ED cardiac arrest. Resuscitation 109, 33–39 (2016).
    5. Kim, H. B., Suh, J. Y., Choi, J. H. & Cho, Y. S. Can serial focussed echocardiographic evaluation in life support (FEEL) predict resuscitation outcome or termination of resuscitation (TOR)? A pilot study. Resuscitation 101, 21–26 (2016).
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Case # 7: A Case of Asymmetry

A 22 year old male presents to the emergency department with a sore throat for 1 week. The pain is predominately on the left side and is associated with difficulty opening his mouth and fever. He was placed on amoxicillin 3 days ago but notes that his symptoms have progressed. He appears uncomfortable.

Vitals: T 101.4 HR 105 BP 132/81  RR 14 O2 98% on RA

A bedside ultrasound is performed, what is the next best step in management?

PTA

Answer and Learning Point

Answer

Incision and drainage. The patient presents with lateralizing pharyngitis symptoms associated with fever and trismus concerning for peritonsillar abscess (PTA). The ultrasound clip demonstrates a well circumscribed, hypoechoic fluid collection abutting the left tonsil confirming this diagnosis (see color overlay below).

Previously, physicians relied solely on the physical exam findings of peritonsillar swelling and uvular deviation to make the diagnosis of PTA. However, this approach lacks accuracy, with studies showing a sensitivity and specificity of 75% and 50% respectively [1]. This uncertainty leads to increased CT utilization, repeat drainage attempts and ENT consultation. Intraoral ultrasound is a novel technique that can be used by emergency physicians (EP), both for diagnosis and drainage of PTA. A recent randomized control trial found the use of intraoral ultrasound (vs. traditional landmark technique) to be significantly more reliable for differentiating between PTA and peritonsillar cellulitis. Additionally, this study also demonstrated increased success in PTA drainage by EPs with the use of intraoral ultrasound guidance [2].

Data from Costantino et al

Learning Points

    • An endocavitary probe should be used when PTA is suspected to differentiated between PTA and peritonsillar cellulitis; and assist with drainage if necessary.
    • If an endocavitary probe is not available, or if the patient cannot open their mouth wide enough to pass the probe, an alternative approach, known as the telescopic submandibular approach can also be used and is explained here.
    • When using ultrasound, the distance from the oral mucosa to the center of the PTA should be measure. The plastic sheath of an 18-gauge needle (preferably a spinal needle to allow the barrel of the syringe to be outside of the patients mouth) should be cut to this length to prevent puncturing any deeper structures during drainage.

Author

This post was written by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

    1. Scott PM, e. (2017). Diagnosis of peritonsillar infections: a prospective study of ultrasound, computerized tomography and clinical diagnosis. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 2 October 2017, from https://www.ncbi.nlm.nih.gov/pubmed/10435129
    2. Costantino TG, e. (2017). Randomized trial comparing intraoral ultrasound to landmark-based needle aspiration in patients with suspected peritonsillar abscess. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 2 October 2017, from https://www.ncbi.nlm.nih.gov/pubmed/22687177
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