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

Right ventricular dilatation on bedside echocardiography performed by emergency physicians aids in the diagnosis of pulmonary embolism

Background

Pulmonary embolism (PE) is a disease entity with a high mortality rate, ranging from 2.5-33%. Frequently, its diagnosis is delayed or frankly missed and often it is only discovered during autopsy. Around 66% of deaths occur during the first hour of presentation and 75% of deaths during the initial hospitalization. The mechanism of morbidity/mortality for PE is thought to be secondary to right ventricle (RV) outflow obstruction, leading to circulatory collapse. Delays in diagnosis have been linked to issues with imaging (wait times, schedules), contrast in the setting of renal impairment, and poor IV access.

In the emergency department, it is not only critical to identify patients with PE, but also to identify those who are at risk for decompensation and poor outcomes. This can be accomplished by evaluating for signs of RV dysfunction which has been associated with RV failure, hemodynamic collapse, and death. Previous studies have shown that right ventricular dysfunction has been found in 27-40% of normotensive patients with PE. Well studied markers of RV dysfunction include elevated biomarkers [1], specific ECG findings (RBBB, tachycardia, S1Q3T3, anterior TWI, ST elevation aVR, atrial fibrillation) [2], and RV dysfunction on echocardiography [3]. While biomarkers and ECG are readily available to emergency providers (EP), these are less specific for the diagnosis of PE and bedside echocardiography may prove to be more useful for evaluation of PE and RV dysfunction.

Right Ventricular Dilatation on Bedside Echocardiography Performed by Emergency Physicians Aids in the Diagnosis of Pulmonary Embolism

Clinical Question

Does evaluation for right ventricular dilation by emergency physicians using bedside echocardiography add diagnostic value in the evaluation for suspected pulmonary embolism? 

Methods & Study Design

  • Design
    • Prospective observational study
  • Population
    • Using a “convenience sample” population of patients who presented to the ED at Boston Medical Center from June 2009 – August 2011, with a moderate to high suspicion (pretest probability) of having a PE.  Wells score 2, those receiving PE imaging (CT, angio, V/Q scan), or those who came in with diagnosis of PE.
  • Exclusion criteria 
    • Non-english speakers
    • Prisoners
  • Intervention
    • Transthoracic echocardiography (blinded of confirmatory results) was performed by 4 ED docs, 1 with advanced training in cardiac sonography.  The other 3 had standard 1-month residency rotation in ultrasound and a minimum of 25 cardiac ultrasounds; plus, 10 hours hands-on and 10 hours image review with principal investigator.
    • Data collection
      • 3 views recorded: parasternal short & long axis, and apical 4-chamber, with primary measurement being qualitative assessment of RV size vs. LV size. Normal ratio (0.6:1)
        • Dilation defined as >1:1 RV:LV ratio
        • RV length and diameter or qualitative distension of RV apex adjacent to LV apex also assessed
      • They also recorded: RV function (nl vs. hypokinetic), paradoxical septal motion, and presence of McConnell’s sign.
      • All image reads were reviewed by the PI.
      • ED RAs then used chart review to compare findings to confirmatory imaging
        • PE was categorized as proximal vs distal
        • Disposition of patient was also documented 
  • Outcomes
    • Diagnostic characteristics
      • Sensitivity, specificity, PPV, NPV, positive and negative likelihood ratios
    • Presence of advanced signs of RV dysfunction
      • Right ventricular hypokinesis [qualitatively assessed as normal or hypokinetic], paradoxical septal motion, and McConnell’s sign

Results

    • Final analysis
      • 146 patients included in study
      • 126 with moderate pretest probability
      • 20 with high pretest probability
      • 126 with normal RV:LV ratio, 17 with increased RV:LV ratio
      • 30 had PE, of these 15 also had increased RV:LV ratio
    • Presence of RV dilation test characteristics
      • Sensitivity 50% (95% CI 32% to 68%)
      • Specificity 98% (95% CI 95% to 100%), a positive predictive value of 88%
      • Positive Predictive Value 88%  negative predictive value of 88%
      • Negative Predictive Value 88% (95% CI 83% to 94%).
      • Positive Likelihood Ratio 29 (95% CI 6.1% to 64%)
      • Negative Likelihood Ratio 0.51 (95% CI 0.4% to 0.7%)
      • Good observer agreement 96%, independent 100%

Strengths & Limitations

  • Strengths
    • Good concordance of sens/spec with prior study observations, although higher sensitivity
    • Good intra-observer agreement/reliability
  • Limitations
    • Single location, young population (less chronic diseases leading to RV changes)
    • Operator skill may not generalize to other physicians, other EDs.  PI was very experienced sonographer.
    • Convenience sample leading to possible selection bias.
    • Secondary outcomes under-powered.

Author's Conclusions

The authors conclude that right ventricular dilatation on bedside echocardiography may help emergency physicians rule in pulmonary embolism more rapidly by raising a provider’s index of suspicion before definitive testing. They also note that this evidence supports the concept that patients with a moderate to high pretest probability for pulmonary embolism and a bedside echocardiography result showing right ventricular dilatation should be considered for anticoagulation before definitive testing.

Lastly, they also comment on severity of PE, noting that patients with signs of advanced right ventricular dysfunction on bedside echocardiography (right ventricular dilatation with right ventricular hypokinesis, McConnell’ s sign, or paradoxical septal motion), tends to occur in patients with a larger clot burden who are more likely to be admitted to an ICU setting or have in hospital mortality (though this study was not powered appropriately for this analysis).

Our Conclusions

 We agree with the author's conclusions of this study that EP performed bedside echocardiography is a useful adjunct in the evaluation of suspected PE, both in identification of PE as well as risk stratification. We know that delays in diagnosis/treatment can lead to worse outcomes, however with the ability of EPs to perform bedside echocardiography and identify right ventricular dilation, this may reduce the time to both of these endpoints. It also seems reasonable that in patients who are moderate to high risk for PE, whom have evidence of right ventricular dilation on bedside echocardiography,  be empirically treated with anticoagulation prior to definitive imaging, with the caveat that they have no high bleed risk.

The Bottom Line

Emergency physician performed bedside echocardiography can be used reliably to increase provider's index of suspicion for PE in patients demonstrating RV dilation; however, given its poor sensitivity, it should not be used as a screening tool for PE.

Authors

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

References

    1. Weekes AJ, e. (2017). Diagnostic Accuracy of Right Ventricular Dysfunction Markers in Normotensive Emergency Department Patients With Acute Pulmonary Embolism. - PubMed - NCBI. Ncbi.nlm.nih.gov. Retrieved 25 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/26973178
    2. Shopp, J., Stewart, L., Emmett, T., & Kline, J. (2015). Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis. Academic Emergency Medicine, 22(10), 1127-1137. doi:10.1111/acem.12769
    3. Dudzinski DM, e. (2017). Assessment of Right Ventricular Strain by Computed Tomography Versus Echocardiography in Acute Pulmonary Embolism. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 25 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/27664798
    4. Dresden S, e. (2017). Right ventricular dilatation on bedside echocardiography performed by emergency physicians aids in the diagnosis of pulmonary embolism. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 25 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/24075286

Case # 6: Not Your Average Syncope

A 25 year old female presents to the emergency department with acute abdominal pain and a syncopal episode. She notes a positive home urine pregnancy test 1 week ago. She appears mildly uncomfortable with a tender abdomen. A bedside ultrasound is performed, a clip is shown below. What are the findings of the ultrasound clip and what is your diagnosis?

Vitals: T 98.7 HR 120 BP 95/72  RR 20 O2 98% on RA

Image courtesy of Elizabeth Owen, MD

Image courtesy of Elizabeth Owen, MD

Answer and Learning Point

Answer

The ultrasound clip demonstrates a large amount of free fluid between the spleen and the diaphragm. There is also a sliver of echogenic material above the capsule of the spleen suggestive of clotted blood. Morison’s pouch (not shown) was also noted to be significantly positive for free fluid. Given the patient’s unstable vitals and the clinical history, this was concerning for a ruptured ectopic pregnancy. OB was consulted immediately and the patient was taken to the OR. The diagnosis of ruptured ectopic pregnancy was confirmed during laparotomy. The patient did well.

While the FAST exam has traditionally been used in trauma, there has been increasing use to diagnose intra-abdominal bleeding as a source of hypotension in medical patients. Specifically with regards to ectopic pregnancy, data has suggested that positive free fluid in Morison’s pouch is highly predictive of operative intervention with a positive likelihood ratio of 112 (Sens 50%, Spec 99.5) [1]. A retrospective study in 2001, looking at emergency medicine physician performed ultrasound, demonstrated that identifying patients with a suspected ectopic pregnancy and free fluid in Morison’s pouch decreased the time to diagnosis and treatment [2].

Learning Points

    • All women of childbearing age presenting with abdominal pain and syncope should be presumed to have a ruptured ectopic pregnancy until proven otherwise
    • Transabdominal ultrasound to evaluate for free fluid should be utilized by the emergency physician in cases of suspected ruptured ectopic pregnancy to assist with risk stratification and rapid diagnosis
    • As in trauma patients, evaluation for free fluid should be performed with the patient supine (or preferably Trendelenburg position as this increases the sensitivity of identifying free fluid in Morison’s pouch [3])
    • A curvilinear (preferred) or phased-array probe should be used to evaluate the abdomen for free fluid and it is critical to completely visualize the most inferior portion of Morison's Pouch, including the caudal tip of the liver & inferior renal pole, as this is where free fluid will collect first
    • A positive pregnancy test and positive free fluid in Morison’s pouch is essentially diagnostic of a ruptured ectopic pregnancy (though ruptured splenic artery aneurysm should also remain on your differential)

Author

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

References

    1. Moore C, Todd WM, O’Brien E. Free Fluid in Morison’s Pouch on Bedside Ultrasound Predicts Need for Operative Intervention in Suspected Ectopic Pregnancy. Acad Emerg Med. 2007; 14(8):755-8.
    2. Rodgerson JD, Heegaard WG, Plummer D, Hicks J, Clinton J, Sterner S. Emergency department right upper quadrant ultrasound is associated with a reduced time to diagnosis and treatment of ruptured ectopic pregnancies. Acad Emerg Med. 2001; 8:331–6.
    3. Abrams BJ, Sukumvanich P, Seibel R, Moscati R, Jehle D. Ultrasound for the detection of intraperitoneal fluid: the role of Trendelenburg positioning. Am J Emerg Med. 1999;17:(2)117-20.

Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions

Background

Point-of-care ultrasound (POCUS) has quickly become a core adjunct used in the emergency department (ED) during cardiopulmonary resuscitation (CPR). Specifically, it is now frequently used to evaluate for reversible causes of cardiac arrest (i.e. cardiac tamponade, pulmonary embolism), guide resuscitation, and prognosticate on patient outcomes based on presenting cardiac activity [1]. However at this time, the benefits of the use of POCUS during CPR are not yet clear in terms of patient centered outcomes. What is known to have an effect on patient outcomes is providing high quality CPR, with minimal interruptions, and early defibrillation [2]. POCUS during CPR is often performed during pulse checks and it can take ample time to obtain sufficient views for proper interpretation. One concern is that this can result in unnecessary delays in resuming chest compressions during CPR, leading to harmful effects on patient outcomes.

Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions

 

Clinical Question

Does use of point-of-care ultrasound (POCUS) in cardiopulmonary resuscitation lengthen the duration of pulse checks beyond the guideline recommendation of 10 seconds?

Methods & Study Design

  • Design
    • Prospective cohort study
  • Population
    • This was a single center study performed at an adult, urban, tertiary care, academic medical center
    • All patients, 18 years of age or older, who presented to the emergency department (ED) in cardiac arrest or in whom cardiac arrest occurred while in the ED were eligible for enrollment
  • Exclusion criteria 
    • No documentation of a pulse check
    • Not placed in one of three designated resuscitation rooms with continuous video monitoring capability
    • Video monitoring obtained was not available or image quality was too poor for extraction of data
  • Intervention
    • All cardiac arrest resuscitations were recorded by video camera
      • Researchers recorded the duration of pulse checks (in milliseconds) and whether POCUS was used
  • Outcomes
    • Duration of pulse checks with the use of POCUS

Results

    • 23 patients enrolled
    • 123 individual rhythm checks
    • The use of POCUS significantly increased the pulse-check duration by 8.4 seconds (95% CI, 6.7-10.0 [p<0.0001])
    • Age and BMI did not affect the duration of pulse checks or CPR interruptions
    • No findings on any of the POCUS images prompted a procedure
    • Survival to ED discharge/hospital admission: 35% (8/23)
    • Survival to hospital discharge: 4% (1/23)
    • Survival at 30 days: 4% (1/23)

Strengths & Limitations

  • Strengths
    • Data collected directly from video which removes any bias on recall of events that occurred during cardiopulmonary resuscitation
  • Limitations
    • Small number of patients included in the study
    • Single center study reduces its external validity
    • No information of level of training of US operators
    • No commentary on the impact of POCUS on mortality or neurologic outcomes

Author's Conclusions

"The use of POCUS during cardiac arrest resuscitation was associated with an increase in the duration of pulse checks by 8.4 seconds, causing interruptions in high-quality chest compressions nearly double the 10-second duration recommended by current international cardiopulmonary resuscitation guidelines. It is critical for acute care providers to pay close attention to the duration of CPR interruptions when using POCUS during cardiac arrest resuscitation."

Our Conclusions

With the introduction of novel indications for POCUS, we need to be aware of both the benefits and harms. This is an important study that identifies a potential harm of POCUS during CPR. There is no doubt from this data that POCUS did result in prolonged pulse checks above the guideline recommended 10 seconds. While this study does not directly tell us that POCUS increases mortality in cardiac arrest (as it is much too small), there is clear evidence that increased interruptions in chest compressions during CPR leads to worse outcomes.

The utility of this study is that it identifies a problem with POCUS in which there are clear solutions. With this new evidence, we must take a thoughtful approach to use of POCUS during CPR. Some proposed solutions to address this problem include:

    • Identifying personnel during CPR who can verbalize the time spent during pulse check to make providers acutely aware of when CPR should be resumed ("10, 9, 8, 7...")
    • Recording a POCUS clip for 5 seconds, then reviewing the stored images while CPR is resumed
    • Having a care provider ready to perform POCUS exam with probe on chest just before chest compressions are withheld
    • Use of transesophageal (TEE) POCUS which allows for image acquisition during ongoing CPR

The findings of this paper are definitely not the end of POCUS in CPR, as I find that there are numerous reasons that it is useful (i.e. monitoring of proper chest compression location, identification of reversible etiology of cardiac arrest, prognostication, closure for health care providers during end of resuscitations...), however I would like to see larger studies on this topic as well as quality improvement and awareness of this potential harm of prolonged pulse checks secondary to POCUS utilization.

The Bottom Line

The use of POCUS during CPR may increase the duration of pulse checks beyond the recommended 10 seconds. Care providers should be aware of this potential harm and measures should be taken to prevent unnecessary delays in chest compressions.

Authors

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

References

    1. Gaspari R, e. (2017). Emergency department point-of-care ultrasound in out-of-hospital and in-ED cardiac arrest. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 8 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/27693280
    2. Link MS et al. Part 7: Adult Advanced Cardiovascular Life Support: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2015 Nov 3;132(18 Suppl 2):S444-64.

    3. Huis In 't Veld MA, e. (2017). Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 8 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/28754527

Case # 5: It’s Not Always Blood

A middle aged male s/p TURBT (transurethral resection of bladder tumor) 1 day ago presented with lower abdominal pain and no urine output from his foley catheter. A bladder scan was performed which was ~ 50 cc. What's the dx?

Vitals: T 98.7 HR 110 BP 117/70  RR 18 O2 98% on RA

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Answer and Learning Point

Answer

The image above is of Morrison's pouch, demonstrating significant free fluid within the peritoneal cavity. Given the recent TURBT and lack of urinary output from the patient's foley catheter, this suggests that the fluid identified is consistent with urine secondary to intraperitoneal bladder perforation. This was later confirmed by CT cystogram and shortly after the patient was taken to the operating room for definitive repair.

Learning Points

    • Bladder perforation from TURBT is relatively rare with an incidence of clinically significant perforations of 1.3%. Furthermore, intraperitoneal bladder perforation only accounts for ~17% of these, making it quite uncommon [1]. A small number of intraperitoneal bladder perforations are also associated with small bowel or colon injury [2].
    • While around 30% of bladder ruptures from TURBT are detected intraoperatively, the remainder present postoperatively (mean time to diagnosis of 6 days) with lower abdominal pain and/or decreased urine output [2].
    • CT cystogram is the gold standard for diagnosis of bladder perforation and can provide information on location of the perforation as well as whether it is intraperitoneal or extraperitoneal [3].
    • As demonstrated in the case above, ultrasound can be used as an imaging adjunct at the bedside to rapidly detect intraperitoneal fluid to expedite consultation with urologic services and definitive CT imaging.
    • The treatment of extraperitoneal perforation of the bladder is usually conservative via prolonged foley catheter drainage. For intraperitoneal lesions, open-surgical exploration and repair is recommended [1-2].
    • Emergency department management of these patients should consist of rapid diagnosis, broad spectrum antibiotic therapy, fluid resuscitation as needed, and urgent urological consultation.

Author

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

References

    1. Rausch S, e. (2017). [Transurethral resection of bladder tumors: management of complications]. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 2 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/?term=24806801
    2. Golan S, e. (2017). Transurethral resection of bladder tumour complicated by perforation requiring open surgical repair - clinical characteristics and oncological outc... - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 2 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/20860654
    3. COMPLICATIONS OF TRANSURETHRAL RESECTION OF BLADDER TUMORS. Eric A. Singer MD, MA and Ganesh S. Palapattu MD. Complications of Urologic Surgery: Prevention and Management, Chapter 25, 295-302

Feasibility and accuracy of bedside transthoracic echocardiography in diagnosis of acute proximal aortic dissection

Background

Acute aortic dissection is a life threatening condition that requires prompt diagnosis and definitive management; dissection involving the ascending aorta is undoubtably an indication for emergent surgical intervention. Previous data suggests that the mortality of type A dissection increases by 1-2% for every hour that passes which further highlights the importance of rapid diagnosis [1-2]. Currently, CT is considered the gold standard that enables the visualization of the entire aorta and can distinguish among the different types of acute aortic syndromes; however this is not always available, requires transferring patients to the CT scanner, and can ultimately generate a significant delay in treatment. Ultrasound is an easily available alternative imaging adjunct that may prove useful in rapid diagnosis of acute aortic dissection, specifically, type A dissection that require emergency surgical intervention.

Feasibility and Accuracy of Bedside Transthoracic Echocardiography in Diagnosis of Acute Proximal Aortic Dissection

 

Clinical Question

What is the accuracy of transthoracic echocardiography (TTE) in the diagnosis of acute type A aortic dissection in comparison to CT (with reference to the intra-operative diagnosis)?

Methods & Study Design

  • Design
    • Retrospective chart review
  • Population
    • This was a single center study involving patients  transferred due to suspected acute type A aortic dissection
    • Cardiac surgery for type A dissection was conducted in 172/178 patients (1 patient refused the operation and died, 5 patients underwent cardiac arrest and died prior to transfer to the operating room)
      • Because intra-operative findings were considered the gold standard reference for the presence of aortic dissection, the 6 patients who died without cardiac surgery were excluded from the final analysis
    • Inclusion criteria:
      • Referral for an urgent surgery due to proximal aortic dissection (Stanford classification Type A)
      • Available results of both CT and bedside TTE
    • Excluded
      • Patients who died prior to cardiac surgery
      • 1 patient who refused surgery
      • Patients who underwent surgical repair of acute type A aortic dissection based on TTE without confirmatory CT
  • Intervention
    • TTE was performed in the emergency department by an “experienced echocardiographer" to evaluate for: maximum ascending aorta diameter, presence of a dissection flap in the ascending aorta, left ventricular ejection fraction, pericardial effusion (and cardiac tamponade), aortic valve morphology and severity of aortic regurgitation
      • Echocardiographic findings were compared to CT findings and intra-operative findings were used as a gold standard
  • Outcomes
    • Identification of type A aortic dissection by TTE
    • Correlation of TTE measurements of maximum ascending aortic diameter with CT and intra-operative findings

Results

    • Statistical analysis with chi square test did not show any statistically significant differences between CT and TTE in the detection of proximal aortic dissection.
    • Additionally, echo revealed concomitant abnormalities (i.e. bicuspid aortic valve, AV calcifications, moderate/severe aortic incompetence, cardiac tamponade), which were all confirmed intra-operatively and influenced the treatment strategy (graft vs. valve-sparing surgery).
    • In patients with any aortic valve abnormalities (bicuspid aortic valve, AV calcifications, significant aortic regurgitation) procedure of choice was replacement by a composite graft (77.59% vs. 49.12%), whereas patients with normal aortic valves were significantly more likely to have the valve sparing surgery (50.88% vs. 22.41%)
    • There was a strong positive correlation between maximum diameter of the ascending aorta measured by TTE and CT (correlation coefficient 0.869)

Strengths & Limitations

  • Strengths
    • This was a feasibility study, and they used a population with known acute type A aortic dissection to determine if TTE could be used to provide both a rapid and reliable diagnosis in proximal aortic dissection
    • Gold standard was intra-operative findings
  • Limitations
    • Retrospective analysis, meaning that the diagnosis of aortic dissection has either already been made or was strongly suspected prior to initiating scanning; some may argue this may falsely increase the noted sensitivity/specificity of TTE
    • All patients who underwent cardiac surgery for acute proximal dissection based on TTE without CT verification (~30% patients at their institution) were excluded from the analysis
    • The TTE was performed by personnel trained in advanced echocardiography which may lower the sensitivity/specificity of these findings in the hands of less experienced operators

Author's Conclusions

"Our data confirm that TTE is a reliable method for diagnosis of proximal aortic dissection. TTE provides a reliable value of maximum diameter of the ascending aorta in comparison to both CT and direct intra-operative measurement. Moreover, TTE gives the additional information that influences the operative technique of choice and identifies the high-risk patients (cardiac tamponade, severe aortic dilatation, severe aortic regurgitation). Our retrospective analysis confirms the pivotal role of TTE in the evaluation of the patients with suspected proximal aortic dissection in emergency room setting."

Our Conclusions

Our conclusions are very similar to author findings on this paper. From the emergency department standpoint, we need the ability to distinguish sick patients from not sick patients and TTE in suspected acute aortic dissection does just that. Looking at this data, TTE measurements of maximum ascending aorta diameter correlate very well with intra-operative measurements. Furthermore, TTE is very accurate at identifying complications of type A aortic dissection such as decompensated heart failure (due to acute aortic regurgitation) and cardiac tamponade, both of which will alter surgical management.

What this means is that if you suspect aortic dissection, a bedside echo should be performed immediately looking for ascending aorta enlargement, dissection flap, and/or complications of dissection. If found, cardiac surgery can confidently be consulted and the patient can either be pushed to the operating room if unstable or pushed directly to the CT scanner by the emergency medicine provider. What this does not mean is that your work up stops here if no findings of dissection are found. If you are truly concerned about aortic dissection then the next step is to proceed with CT for definitive rule out. For more information on evaluation of acute aortic dissection, please read our recent case here.

The Bottom Line

The use of TTE in suspected proximal aortic dissection facilitates a rapid and reliable diagnosis, and shortens the delay to definitive treatment in a subset of high-risk patients.

Authors

This post was written by Ryan Shine, MS-4 at UCSD. It was edited by Michael Macias, MD.

References

    1. HIRST AE Jr, e. (2017). Dissecting aneurysm of the aorta: a review of 505 cases. - PubMed - NCBI Ncbi.nlm.nih.gov. Retrieved 26 August 2017, from https://www.ncbi.nlm.nih.gov/pubmed/13577293

    2. Hagan PG, e. (2017). The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. - PubMed - NCBI Ncbi.nlm.nih.gov. Retrieved 26 August 2017, from https://www.ncbi.nlm.nih.gov/pubmed/10685714

    3. Sobczyk, D., & Nycz, K. (2015). Feasibility and accuracy of bedside transthoracic echocardiography in diagnosis of acute proximal aortic dissection. Cardiovascular Ultrasound, 13(1). doi:10.1186/s12947-015-0008-5

Case # 4: To Bolus or Not to Bolus?

 

 

A 67 year old male with a PMHx of DM presents with a chief complaint of cough and generalized weakness.

Vitals: T 102.4 HR 127 BP 77/58  RR 24 O2 88% on RA

You place the patient on O2 via nasal cannula and activate the sepsis protocol. He is empirically treated with broad spectrum antibiotics and IVFs are started. The chest x-ray shows multifocal pneumonia and you call hospital medicine to admit the patient.  “What’s the blood pressure now,” the hospitalist asks. You glance at the monitor and murmur back, “92/63, but he looks pretty good.” The hospitalist asks you to insert a central line, start vasopressors, and contact the ICU. Instead, you wheel the ultrasound machine into his room, and ultrasound his IVC. Does this patient require a central line and vasopressors?

Answer and Learning Point

Answer

No, the patient’s IVC is small and collapsing almost 75% with normal respiratory variation. This predicts a fluid-responsive state. The patient was given another liter of lactated ringers, his blood pressure improved to 108/69, and his lactate cleared. You start maintenance IV fluids, call the hospitalist back, and the patient is admitted upstairs and does well.

Learning Points

    • Fluid responsiveness is a controversial topic that continues to plague emergency medicine physicians and intensivists alike
    • In patients whom a fluid bolus is being considered, ultrasound can be a useful tool to assess for cardiac function, lung fluid status (interstitial edema) and whether a patient will improve their cardiac output in response to this fluid challenge
    • A recent study showed that the cIVC (inferior vena cava collapsibility) can be used as a predictor of who will be a fluid responder [1]
      • cIVC = (IVC expiratory diameter - IVC inspiratory diameter)/IVC expiratory diameter
      • Patients with a cIVC > 25% are likely to be fluid responders (LR + 4.56)
      • Patients with a cIVC < 25% are unlikely to be fluid responders (LR - 0.16)
    • The IVC should be examined in the subxiphoid region with the probe in a sagittal plane, and can be found by first identifying the right atrium and following this caudally
      • A back-up approach involves using the liver as an acoustic window , placing the probe in the mid axillary line in a coronal plane,  and fanning anteriorly and posteriorly until the IVC is visualized
      • The IVC should be measured 3 cm caudal to the junction of the right atrium and IVC [2]
    • M-mode can be used to evaluate the cIVC and has the advantage of measuring the exact same spot along the IVC over an extended period of time
    • As with all adjuncts to clinical decision making, fluid responsiveness should not be determined solely on a single ultrasound measurement such as cIVC but should be taken into context with the rest of the clinical picture

Author

This post was written by Amir Aminlari, MD, Ultrasound Fellowship Director at UCSD.

References

Corl KA, e. (2017). Inferior vena cava collapsibility detects fluid responsiveness among spontaneously breathing critically-ill patients. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 19 August 2017, from https://www.ncbi.nlm.nih.gov/pubmed/28525778

Nagdev AD, e. (2017). Emergency department bedside ultrasonographic measurement of the caval index for noninvasive determination of low central venous pressure. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 19 August 2017, from https://www.ncbi.nlm.nih.gov/pubmed/19556029

Diagnosing Acute Heart Failure in the Emergency Department: A Systematic Review and Meta-analysis

Background

The chief complaint of “dyspnea” represents a very large cohort of patient who present to the emergency department. While acute heart failure (AHF) is a very common diagnosis in the setting of dyspnea, the diagnosis remains challenging when the emergency physician is presented with the undifferentiated dyspneic patient. Interestingly, emergency physicians have varied approaches to the work up and diagnosis of these patients and it is not clear as to which diagnostic element is most crucial in confirming the diagnosis of AHF. Spoiler: Ultrasound proves to be quite useful.

Diagnosing Acute Heart Failure in the Emergency Department: A Systematic Review and Meta-analysis‌

 

Clinical Question

What are the operating characteristics of the diagnostic elements available to the emergency physician for diagnosing acute heart failure?

Methods & Study Design

  • Design
    • This is a systematic review evaluating index test operating characteristics in diagnosing AHF. A medical literature search was performed using PubMed and EMBASE, evaluating peer-reviewed published papers from 1965 through 2015
    • Individual systematic reviews for each index test were conducted by two separate physicians and thereafter reconciled to obtain a comprehensive set of studies on the topic. These were then screened against the inclusion/exclusion criteria for final inclusion into the meta-analysis
    • The reference standard used was a final diagnosis of AHF based on review of clinical data by independent reviewers who were blinded to the study’s primary index test
  • Population
    • All studies included involved patients presenting to the emergency department (ED) with the chief complaint of “dyspnea.”
  • Outcomes
    • Pooled sensitivities, specificities and likelihood ratios (LRs) of index tests for diagnosing acute heart failure in patients presenting to the ED with dyspnea
    • They specifically looked at the following index tests in evaluation of AHF: history and physical exam, ECG, chest x-ray, BNP and NT-ProBNP, lung ultrasound (US), and bedside echocardiography
  • Excluded
    • Patients presenting to urgent care with dyspnea
    • Patients with chronic, compensated heart failure
    • Studies focusing on prognosis or therapeutics and not the diagnosis of AHF
    • Studies with ultrasound images that were not obtained and interpreted by emergency physicians

Results

    • History and Physical: S3 most specific finding for AHF (+LR 4)
    • ECG: Found to be insensitive and unspecific for diagnosing or ruling out AHF
    • CXR: Pulmonary edema was the most specific finding (LR + 4.8). All other imaging findings were insensitive for ruling out heart failure
    • BNP and NT-Pro-BNP: Quite sensitive for ruling out AHF at a threshold of 100/300pg/dL
    • Lung Ultrasound:
      • Presence of >3 B-lines in >2 lung fields is very specific for the presence of AHF
      • Lack of this also sensitive for ruling out acute heart failure
      • High inter-rater reliability
    • Bedside Echo
      • ED provider evaluation of systolic function had high inter-rater reliability with the ultimate ejection fraction assessed by cardiologists on formal echo
      • Restricted Mitral Inflow very specific for ruling in diastolic AHF in patients with preserved systolic function

Strengths & Limitations

  • Strengths
    • Very thorough analysis of the operating characteristics of a plethora of diagnostic elements and sub-elements available to the emergency physician in diagnosing AHF
    • Authors didn’t exclude comorbidities, etiology of AHF or if there was an underlying arrhythmia which increased the generalizability of their results
    • All data was screened and evaluated by two separate physicians
  • Limitations
    • The reference standard was a final diagnosis of AHF made by physicians in retrospective fashion which weakens this as a “gold standard.”
    • The authors did not specifically evaluate or reconcile whether the heart failure was left or right sided
    • Each of the tests or test characteristics were assessed in isolation to determine the likelihood of heart failure. The likelihood of AHF when considering multiple index tests was not assessed
    • As in all large meta-analyses, some spectrum bias may exist as inclusion/exclusion criteria varied among included studies. However, ome of this heterogeneity is likely countered by the pooled analysis and is unlikely to drastically change the calculated LRs

Author's Conclusions

"Bedside lung US and echocardiography appear to the most useful tests for affirming the presence of AHF while natriuretic peptides are valuable in excluding the diagnosis."

Our Conclusions

This is one of the most thorough studies available to assess the likelihood that a patient presenting to the emergency department has acute heart failure based on an index test. There are many old standby diagnostic modalities available to emergency physicians including the history, physical exam, and chest x-ray. Unfortunately, these diagnostic elements are relatively non-specific in establishing that a patient’s acute symptoms are likely or unlikely due to heart failure. BNP and NT Pro BNP are quite useful in ruling out heart failure however these tests take time to result. Ultrasound is rapidly becoming a fundamental tool in every emergency physicians tool belt and should be utilized alongside the primary patient assessment in determining the likelihood that a patient has heart failure. The presence or absence of B lines (>3 in at least 2 fields) is quite specific for ruling in heart failure and the absence is nearly as sensitive as a normal BNP or NT Pro BNP, too. And in the event of systolic heart failure, echo is a great modality to rapidly assess a patient’s pump function; our interpretation is consistent with the formal result obtained by cardiologists [2].

Caution must nevertheless be maintained when evaluating these results. The LRs found in these studies were calculated independently of other findings and in reality, the emergency physician takes multiple factors from the history, physical exam, and other diagnostic modalities, to ultimately come to a definitive diagnosis. Essentially, the short answer is that no single test should be taken as definitive in diagnosis of AHF (or any diagnosis for that matter) and the emergency physician should follow a bayesian approach using pre- and post- test probabilities from their fund of knowledge to rule in and rule out cannot miss diagnoses. Lastly, with regards to this study, physicians should be wary about interpreting these results in the context of renal failure primarily but also superimposed pneumonia or underlying concern for pulmonary embolism as these patients were excluded in a number of papers included in this meta-analysis.

The Bottom Line

Bedside ultrasound to evaluate for the presence or absence of pulmonary edema should be an integral part of the emergency physicians approach to evaluating patients to the emergency department with undifferentiated dyspnea.

Authors

This post was written by Matt Correia, MD PGY-2 at UCSD. It was edited by Michael Macias, MD.

References

    1. Martindale JL, e. (2017). Diagnosing Acute Heart Failure in the Emergency Department: A Systematic Review and Meta-analysis. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 14 August 2017, from https://www.ncbi.nlm.nih.gov/pubmed/26910112
    2. Moore CL, e. (2017). Determination of left ventricular function by emergency physician echocardiography of hypotensive patients. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 14 August 2017, from https://www.ncbi.nlm.nih.gov/pubmed/11874773

Case # 3: Under Your Skin

A 52 year old male with presents with 4 days of painful swelling and redness to his middle right thigh. Physical exam shows a 3 cm area of erythema that is tender to touch. He denies fever and trauma to the area. A bedside ultrasound is performed as seen below. What is the next step in management?

Vitals: HR 82 BP 110/72 RR 14 O2 98

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Answer and Learning Point

Answer

Incision and drainage. The image above demonstrates a well circumscribed fluid collection within the soft tissue,  without evidence of surrounding cellulitis. The above abscess was incised with immediate release of a large volume of purulent material. The patient did well.

Learning Point

    • Ultrasound is an excellent adjunct to the physical exam in the evaluation of soft tissue infections. It improves accuracy in the diagnosis of superficial abscesses and has been shown to change management in up to 50% of emergency department cases of clinical cellulitis [1,2].
    • The ultrasound image above is atypical for an abscess given the iso-echoic texture appreciated in the fluid and is easily missed if the operator is not aware of this unusual finding. Most abscesses will appear as a hypoechoic fluid collection, however occasionally they may have increased internal echoes which can lead to false negative ultrasound results.
    • This can be avoided by applying gentle pressure to the area of the suspected cellulitis/abscess to evaluate for the "swirl sign" which is indicative of fluid movement within the abscess cavity [Figures 1&2].
    • This can be distinguished from the common pattern appreciated in cellulitis known as "cobblestoning" which indicates increased subcutaneous fluid.
Figure 1: Soft tissue ultrasound demonstrating swirling of iso-echoic fluid collection consistent with abscess. Image courtesy of UOTW.
Figure 2: Additional soft tissue ultrasound demonstrating the "swirl sign." Image courtesy of UOTW.

References

 Tayal VS, e. (2017). The effect of soft-tissue ultrasound on the management of cellulitis in the emergency department.

Squire BT, e. (2017). ABSCESS: applied bedside sonography for convenient evaluation of superficial soft tissue infections.

UOTW: Case 66

Comparison of Four Views to Single-View Ultrasound Protocols to Identify Clinically Significant Pneumothorax

Background

Ultrasound has become a key adjunct for the initial evaluation of trauma patients in the emergency department (ED), with the eFAST, or extended focused assessment with sonography in trauma examination, including lung evaluation for the presence of a pneumothorax (PTX) or hemothorax. While prior research has shown ultrasound (US) to be very effective at identifying a PTX [1], there is no standardized imaging protocol that has been shown be superior to others. The two most common approaches are a single view of each hemithorax and four views of each hemithorax [2] —this paper sets out to determine if the single view strategy is sufficient to identify a clinically significant PTX.

Comparison of Four Views to Single-view Ultrasound Protocols to Identify Clinically Significant Pneumothorax

 

Clinical Question

Does the single-view or four-view lung US technique have a higher diagnostic accuracy for the identification of clinically significant PTX in trauma patients?

Methods & Study Design

  • Population
    • The study was conducted at a single urban academic ED with an annual volume of 130,000 patients and a dedicated Level I trauma service staffed by trauma surgeons and EM physicians. Adult patients with acute traumatic injury who were undergoing a CT scan of the chest as part of their clinical care were eligible for enrollment.
  • Intervention
    • Patients were assigned to one of two imaging protocols, a single view of each hemithorax or four views of each hemithorax prior to any CT imaging being done, with US images obtained by emergency physicians or the attending trauma surgeon using a 7.5-Mhz (5- to 10-MHz) linear array transducer. US exams were performed by both residents and attending physicians who had been credentialed in both US protocols.
  • Outcomes
    • Researchers looked for the ability of US to identify clinically significant PTX requiring chest tube placement; a PTX was considered clinically insignificant if the radiologist, who was blinded to the US interpretation, read the CT scan as a thin collection of air up to 1 cm thick in the greatest slice or seen on fewer than five contiguous slices.
  • Design
    • This was a randomized, prospective trial on trauma patients.
  • Excluded
    • The study excluded any patient who was too unstable and required clinical care that prevented performing a chest wall US, patients with a chest tube in place prior to arrival, children, pregnant women, and prisoners.

Results

    • For clinically significant PTX, CXR showed a sensitivity of 48.0% and specificity of 100%, a single view US showed a sensitivity of 93.0% and a specificity of 99.2%, and four views showed a sensitivity of 93.3% and specificity of 98.0%. There was no statistically significant difference in either sensitivity or specificity when comparing single view and four-view for clinically significant or any PTX.

Strengths & Limitations

  • Strengths
    • Randomized, prospective trial
    • 100% agreement between the initial US read by the performing provider and the study author, for a Cohen’s kappa of 1
  • Limitations
    • Study was conducted at a single center with a limited number of US operators
    • Standard prehospital approach to spinal immobilization that results in placement of patients supine on a long board - in areas where this approach may differ (e.g., patients arrive semirecumbent or upright), the positioning of a PTX in the chest may be altered, rendering a single view of the anterior chest wall less accurate
    • As this study was a convenience sample that required the treating physician to remember to enroll the patient and randomize them prior to performing the US, there is a possibility of selection bias

Author's Conclusions

"The sensitivities are equivalent for both a single view and four views of each hemithorax when using point-of-care ultrasound to evaluate for a clinically significant pneumothorax in the trauma population.  The additional time required for additional views should be weighed against the lack of additional diagnostic accuracy when evaluating critically ill and time-sensitive trauma patients in the ED."

Our Conclusions

Although not all PTXs are located anteriorly and multiple views of each hemithorax may be thought to maximize sensitivity and/or allow the physician to be able to attempt to quantify the size of the PTX, performing eight views instead of two views during the eFAST requires extra time while adding no diagnostic value.  From this study, it appears that a single view on each side of the thorax is sufficient to detect clinically significant PTXs on trauma patients.

As with any diagnostic tool, it is important to remember its limitations. Specifically, the US exams in this study were done in supine patients, who were brought in by EMS in a supine position, allowing the pneumothorax to move to the most anterior portion of the chest. Caution should be taken when applying the test characteristics of this study to patients that are not in the supine position. There was also one patient who had a significant PTX that was missed by US and required a chest tube. This patient had received a needle decompression by prehospital providers and was randomized to a single anterior US chest view that was performed just lateral to the needle insertion site which may have led to false negative US exam. It appears this specific group of patients may benefit from a more comprehensive four-view lung examination.

 

The Bottom Line

A single anterior view on each side of the chest in a supine patient is sufficient to detect clinically significant pneumothoraces.

Authors

This post was written by Ben Foorman, MS4 at UCSF. It was edited by Michael Macias, MD.

References

    1. Lichtenstein DA, e. (2017). Ultrasound diagnosis of occult pneumothorax. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 28 July 2017, from https://www.ncbi.nlm.nih.gov/pubmed/15942336
    2. Blaivas M, e. (2017). A prospective comparison of supine chest radiography and bedside ultrasound for the diagnosis of traumatic pneumothorax. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 28 July 2017, from https://www.ncbi.nlm.nih.gov/pubmed/16141018
    3. Helland G, e. (2017). Comparison of Four Views to Single-view Ultrasound Protocols to Identify Clinically Significant Pneumothorax. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 28 July 2017, from https://www.ncbi.nlm.nih.gov/pubmed/27428394