December 16, 2019

Background: The clinical diagnosis of pulmonary embolism (PE) can be challenging given its variable presentation, thus requiring dependence on objective testing. decision instruments such as PERC and the Wells’ score help stratify patients to low or high probability, enabling focused use of CT pulmonary angiography (CTPA) for diagnosis. However, despite these algorithms, there is evidence of increasing use of CTPA along with diminishing diagnostic rates (less than 10%). This combination results in the overdiagnosis of subsegmental PEs, unnecessary exposure to radiation and false positive results.

Though the D-dimer test has long been maligned for its low specificity the real issues around it rest in indiscriminate use and threshold value. In recent years, age-adjustment of the D-dimer and the YEARS algorithm have attempted to adjust the threshold in order to “rule-out” more patients without advanced imaging. The YEARS creates a two-tiered D-dimer threshold by first asking three questions:

  1. Are there clinical signs of DVT?
  2. Does the patient have hemoptysis? and
  3. Is PE the most likely diagnosis.

If the answer to all 3 questions is no, the D-dimer threshold is set at 1000 ng/mL FEU (500 ng/mL DDU) and if the answer is “yes” to any of the 3 questions, the D-dimer threshold is set at 500 ng/mL FEU (250 ng/mL DDU). More recently, the YEARS algorithm has been assessed in pregnancy.

Age-adjustment of the D-dimer assay simply multiplies 10 X the patients age (if using FEU and 5 X age if using DDU) and uses this number as the threshold for the test. This adjustment is applied to patients > 50 years of age. Age-adjustment of the D-dimer was endorsed by an ACEP clinical policy in 2018.

The PEGeD study is another attempt to show the safety of using an adjusted D-dimer threshold.

December 12, 2019

Background: The 2015 American Heart Association guidelines for Adult Advanced Cardiac Life Support recommend adenosine in non-hypotensive patients in regular narrow-complex supraventricular tachycardia (SVT).  Adenosine has a rapid onset and a half-life that is <10 seconds, which makes it an ideal agent for hemodynamically stable SVT. Typically, adenosine is administered as an initial 6mg rapid IV bolus over 1 – 2 seconds followed by a rapid 10 – 20mL saline flush.  If SVT is not terminated and normal sinus rhythm maintained within 1 – 2 minutes, a repeat dose of 12mg is given followed by a 10 – 20mL saline flush, and this can be repeated for a total of 3 doses. Because of the short half-life of adenosine, several advocate for a two-way stopcock, where adenosine and a 10 – 20mL saline flush are given in tandem. The logistics and timing with using a two way stopcock can be challenging and can result in less rapid flush than intended.

October 31, 2019

Take Home Points  
  • Stress cardiomyopathy looks like ACS/STEMI, with patient presenting with chest pain, dyspnea or maybe syncope. It looks like ACS and should be treated as such until you prove to yourself it’s not.
  • Classic patient is an older woman with chest pain or syncope after a stressful event.
  • Bedside echo will show left ventricular dysfunction with one of a variety of patterns of wall motion abnormality. The most common is apical, but there are also variant patterns including mid-ventricular, basal, focal and global.
  • Watch for QTc prolongation as this could precipitate an arrhythmia. Be sure to stop all QT prolonging meds and replete magnesium
  • Consider the differential in the patient who has cardiogenic shock because the treatment differs. Avoid catecholamines and if you need inotropic support use dobutamine or dopamine. Look for evidence of left ventricular outflow tract (LVOT) obstruction, as this should be treated like a hypertrophic cardiomyopathy with beta blockers rather than inotropes.

October 21, 2019

Background Information: Atrial fibrillation is the most commonly encountered dysrhythmia in the emergency department (ED) and is associated with an increased long-term risk of stroke, heart-failure and all-cause mortality.1,2 In fact, the overall mortality rate for patients with atrial fibrillation is approximately double that of patients in normal sinus.3,4 The decision to rate vs. rhythm control patients while in the emergency department remains controversial in the literature and the method of doing so using chemical vs. electrical cardioversion also stirs up debate. Prior studies have shown the success rate of electrical cardioversion alone to be 90%.1,5 other studies have demonstrated that emergency physicians use each strategy roughly half the time.1 The authors of this study sought to determine if one of the two strategies resulted in achievement of normal sinus rhythm and discharge more quickly.
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