Month: January 2018

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Prospective Outcomes of Pregnant ED Patients with Documented Fetal Cardiac Activity on Ultrasound

Background

Vaginal bleeding is a common cause of presentation to the emergency department (ED), and is the leading cause of presentations to the ED among patients with first trimester pregnancy [1]. It is reported that up to 25% of pregnancies have some bleeding within the first trimester [2]. Based on previous data, bleeding in the first trimester represents an increased risk of spontaneous abortion (SAB), with up to 50% of women losing the pregnancy [3]. However, patients with first trimester bleeding and a documented intrauterine pregnancy (IUP)  with fetal heart tones (FHTs), represent a subset of first trimester bleeding patients with improved outcomes, with rates of SAB ranging from 11.1-16.4% [4-5]. These previous studies were performed in outpatient obstetrical clinics and no prospective data exists with respect to outcomes in this subset of patients presenting to the emergency department. 

Prospective Outcomes of Pregnant ED Patients with Documented Fetal Cardiac Activity on US

Clinical Question

What is the rate of SAB in pregnant women presenting to the ED with first trimester bleeding and a documented IUP with cardiac activity?

Methods & Study Design

  • Design
    • Prospective observational study
    • Convenience sample of pregnant patients presenting to the University of Utah ED from January 1, 2008 through April 30, 2010.
  • Population
    • Pregnant women presenting to the ED with abdominal pain and/or bleeding
  • Inclusion criteria
    • Ultrasound (performed by ED physician at bedside or formal radiology study) demonstrating an IUP with FHTs and whose pregnancy dates placed them in the first trimester (< 13 weeks)
  • Exclusion criteria
    • No specific criteria
  • Intervention
    • Ultrasound demonstrating IUP with FHTs
  • Outcomes
    • Rate of SAB at 30 days after ED visit
    • Patients were contacted by telephone at least 30 days after their ED visit and asked about the status of their pregnancy

Results

Strengths & Limitations

  • Strengths
    • Performed in ED based population
    • Majority of ultrasound examinations performed by ED physicians making this applicable to point-of-care ultrasound
  • Limitations
    • Performed at single academic center
    • Low patient enrollment leading to large CI for rate of SAB
    • 85.9% patient follow up rate
    • Patients only followed out to 30 days after ED visit

Authors Conclusion

"In this prospective study of ED patients with first trimester bleeding and/or pain, we found that patients who had an IUP and FHTs by ED US had a 14.8% rate of SAB at 30 days. These findings may help to better define risk of SAB after first-trimester bleeding and allow us to provide more accurate counseling and prognostic information to pregnant ED patients presenting with these symptoms.”

Our Conclusion

This is an excellent paper that helps provide emergency medicine providers with prognostic information  regarding women presenting to the ED during first trimester pregnancy with vaginal bleeding and a documented IUP with FHTs. Often in emergency medicine we are focused on ruling out the life threatening diagnoses, in the above scenario, ectopic pregnancy, and it can be easy to lose sight of other important aspects of patient care. This paper helps refocus our attention and gives us important data to be able to provide an already anxious patient with some useful information on the potential expected course of their pregnancy. With this data, we are now able to better define the risk of SAB after first trimester bleeding and provide improved counseling and prognostic information to these patients.

The Bottom Line

In ED patients with first trimester bleeding, those that have an IUP and FHTs by ED ultrasound have ~15% rate of SAB at 30 days. 

Authors

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

References

    1. Dighe M, Cuevas C, Moshiri M, Dubinsky T, Dogra VS. Sonography in first trimester bleeding. J Clin Ultrasound 2008;36(6):352-66.
    2. Hasan R, Baird DD, Herring AH, Olshan AF, Jonsson Funk ML, Hartmann KE. Patterns and predictors of vaginal bleeding in the first trimester of pregnancy. Ann Epidemiol 2010;20(7):524-31.
    3. Dideriksen KL, Lidegaard O, Langhoff-Roos J. First trimester vaginal bleeding and complications later in pregnancy. Obstet Gynecol 2010;115(5):935-44.
    4. Poulose T, Richardson R, Ewings P, Fox R. Probability of early pregnancy loss in women with vaginal bleeding and a singleton live fetus at ultrasound scan. J Obstet Gynaecol 2006;26(8):782-4.
    5. Siddiqi TA, Caligaris JT, Miodovnik M, Holroyde JC, Mimouni F.Rate of spontaneous abortion after first trimester sonographic demonstration of fetal cardiac activity. Am J Perinatol 1988;5(1):1-4.
    6. Mallin M, e. (2018). Prospective outcomes of pregnant ED patients with documented fetal cardiac activity on ultrasound. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 26 January 2018, from https://www.ncbi.nlm.nih.gov/pubmed/21334156
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Case # 12: Bilateral Vision Loss

A 45 year old male with poorly controlled DM presents with bilateral vision loss. His right eye vision acutely worsened 3 days ago with the sensation of a curtain moving back and forth across his visual field. Today his left eye vision acutely worsened with flashes and floaters occurring. He denies any trauma, headache, or new medications.

Vitals: T 98.6 HR 90 BP 149/87  RR 16 O2 98% on RA

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

Left Eye

Left Eye

Right Eye

Right Eye

Answer and Learning Points

Answer

The ultrasound clips demonstrate hypoechoic material in the orbits bilaterally, swirling around with subtle eye movement. This is consistent with bilateral vitreous hemorrhage. The diagnosis was discussed with the patient and he was referred to ophthalmology clinic for dilated eye exam in 24 hours.

Learning Points

Vitreous hemorrhage is a common diagnosis (though usually unilateral) seen in poorly controlled diabetes. The most frequent etiologies include proliferative diabetic retinopathy, posterior vitreous detachment, and ocular trauma, with trauma more common in patients under the age of 40. Since it is difficult to obtain  a good physical exam of the posterior aspects of the eye without a dilated exam, there is high utility in the use of point of care ultrasound in evaluating for acute pathology.  It can be used to distinguish vitreous hemorrhage and retinal detachment, which have significantly different prognoses and treatment pathways. To perform an ocular ultrasound, follow these steps:

    1. Prepare the patient by laying the bed backwards and having their face parallel to the ceiling,  supporting the patient's head and neck with a pillow or blanket.
    2. Place a tegaderm over the eye (optional). If you do, ensure there is no air between the tegaderm and the eyelid.
    3. Place the ultrasound gel on the tegaderm and prepare the linear probe with the gain turned almost all the way up (this will help you visualize both retinal detachment and vitreous hemorrhage.
    4. Stabilize your hand on the patient's nasal bridge or zygoma, with the probe marker to your left, and place the probe transverse on the orbit with minimal pressure being applied directly to the eye.
    5. Adjust the depth to ensure the optic nerve is just visualized at the bottom of the screen. The anterior chamber and lens should be used as visual landmarks to ensure you are in proper location. Next, have the patient look up, down , left and right (oculokinetic echography), to assess for any abnormalities in the posterior aspects of the eye.
    6. Repeat this technique with the probe marker pointed superiorly and have the patient again look in all directions.

Retinal detachment: The common POCUS findings include a thin linear structure tethered to the optic nerve.  It flaps back and forth as the eye is moved giving it the appearance of “swaying seaweed”. This is an ophthalmologic emergency, especially if the macula is still attached,  the ophthalmologist should be immediately consulted.

Vitreous hemorrhage: You will notice a diffuse mobile opacity often described as a “snow globe” that is exacerbated with moving the eye from side to side. If this is seen in a diabetic patient with floaters, there is a high likelihood that the diagnosis is a vitreous hemorrhage. These patients will still need follow up with ophthalmology for further management, but typically there will not be an emergent intervention.

Author

This post was written by Sam Frenkel, MD, PGY-2 UCSD EM. It was reviewed by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

    1. Yoonessi R, Hussain A, Jang TB. Bedside ocular ultrasound for the detection of retinal detachment in the emergency department. Acad Emerg Med. 2010;17(9):913-7.
    2. Dawson, Mallin. Introduction to Bedside Ultrasound, Volume 2. 2013. Apple iBook.
    3. Kilker B, Holst J, Hoffmann B. Bedside ocular ultrasound in the emergency department. Eur J Emerg Med. 2014;21(4):246-253.
    4. Shinar Z, Chan L, Orlinsky M. Use of ocular ultrasound for the evaluation of retinal detachment. J Emerg Med. 2011;40(1):53-57. 
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Ultrasound Guided Catheterization of the Radial Artery

Background

Arterial catheterization (the radial artery being the most common site)  is often performed in critically ill patients for hemodynamic monitoring and serial blood gas sampling, and is a core skill for critical care and emergency providers alike. While ultrasound guidance has become standard of care for  central venous catheterization, this is still not common practice for radial artery catheterization. In this critically ill patient population, there are often patient specific factors that make this procedure difficult using the palpation method, including hypotension, edema and obesity. Frequently, the palpation method requires multiple attempts which can result in arterial vasospasm, making further attempts even more difficult. This review article investigates whether their is a role for the addition of ultrasound guidance to radial artery catheterization. 

Ultrasound-Guided Catheterization of the Radial Artery 

Figure 1: Flow diagram of study identification, inclusion, and exclusion

Figure 1: Flow diagram of study identification, inclusion, and exclusion

Figure 2: Summary of RCTs of ultrasound-guided arterial catheterization

Figure 2: Summary of RCTs of ultrasound-guided arterial catheterization

Figure 3: Effect of ultrasound-guided catheterization of first attempt success

Figure 3: Effect of ultrasound-guided catheterization of first attempt success

Figure 4: Effect of ultrasound guided catheterization on first attempt success

Figure 4: Effect of ultrasound guided catheterization on first attempt success

Clinical Question

Does ultrasound guidance for radial artery catheterization improve first attempt success compared to the palpation method? 

Methods & Study Design

  • Design
    • Systematic Review and Meta-analysis of Randomized Controlled Trials
      • Article selection
        • Databases searched: EMBASE, CENTRAL, and Medline from inception through February 23, 2010
        • Critical care conference abstracts reviewed from 2005-2009
        • Experts in the field also contacted to seek additional articles
        • The methodologic quality of selected trials was appraised by two independent reviewers using the Jadad criteria
  • Population (See Figure 1)
  •  Heterogenous population of adults and pediatric patients in different clinical settings
  • Inclusion criteria
    • Randomized control trials comparing 2-D ultrasound guidance technique to traditional palpation technique for radial artery catheterization
  • Exclusion criteria
    • Trials evaluating use of doppler ultrasonography, marking techniques, or catheterization of arteries other than the radial artery were excluded
  • Intervention
    • Ultrasound guided radial artery catheterization
  • Outcomes
      • First-attempt success for radial artery catheterization

Results

    • A total of 4 RCTs were included in the final meta-analysis. Individual characteristics can be viewed in figure 2.
    • Pooled Findings
      • The pooled relative risk for ultrasound guided techniques was 1.71 (95% CI, 1.25-2.32). The forest plot can be seen in figure 3 with data provided in figure 4.

Strengths & Limitations

  • Strengths
    • Comprehensive literature search
    • Included only RCTs comparing traditional palpation technique to ultrasound guided technique for radial artery catheterization
    • Adequate sample size obtained which reached statistical significance with respect to outcome
    • Studies independently reviewed by two reviewers for inclusion in meta-analysis
  • Limitations
    • The patient populations were very heterogenous among RCTs (1 adult surgery population, 1 infant neurosurgery population, 1 adult ED population, 1 pediatric surgery population)
    • The operator populations were very heterogeneous among RCTs (anesthesia attendings/residents, emergency physicians, pediatric trainee and consultant anasthesiologists)
    • Lack of blinding

Author's Conclusions

 "Our meta-analysis clearly demonstrated a 71% increase in the likelihood of first-attempt success when using ultrasound guidance for radial artery catheterization."

Our Conclusions

Radial artery catheterization is fraught with error and barriers to success. Often this procedure will be performed in sick patients, with the operator encountering obesity, edema, and shock, all of which can contribute to difficulty palpating the radial pulse. Furthermore, even if the pulse is palpated, this can be unreliable at predicting underlying anatomy. Ultrasound allows direct visualization of the radial artery, including depth, diameter and surrounding structures, and allows for ongoing needle guidance. While not studied, in my personal experience I have also noted numerous occasions where the only sign of successful radial artery catheterization was direct visualization of the catheter tip in the radial artery (i.e. no blood seen in flash chamber) on ultrasound. If the standard palpation method was used, this would lead to a failed attempt.

It has become clear in many other instances that ultrasound adds safety and success to procedures routinely performed in the emergency department including: central venous access, thoracentesis, paracentesis, peripheral nerve blocks and arthrocentesis (of specific joints). This study allows us to confidently add radial artery catheterization to the list. While the patient population and operators in the study discussed are heterogeneous, it is reasonable to assume that emergency medicine providers who have experience with ultrasound guided procedures, will perform just as well, if not better than the study findings.  This generalization assumes ultrasound guided procedure experience and those without this experience may not show a benefit over the traditional palpation method for radial artery catheterization. This study does not mean that the palpation method is obsolete, rather, it suggests that ultrasound is a useful adjunct and likely adds success in patients with risk factors for difficult radial artery catheterization such as obesity, hypotension, edema or a difficult to palpate pulse.

The Bottom Line

Ultrasound guidance for radial artery catheterization shows a higher first-attempt success rate compared to the standard palpation method and should be considered by operators with other procedural ultrasound guidance experience. 

Authors

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

References

    1. Shiloh AL, e. (2018). Ultrasound-guided catheterization of the radial artery: a systematic review and meta-analysis of randomized controlled trials. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 13 January 2018, from https://www.ncbi.nlm.nih.gov/pubmed/20724734

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