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.

December 9, 2019

You are working at a Level 1 Trauma Center; a 35-year-old female arrives via EMS from the scene of a motor vehicle accident. She was an unrestrained passenger, ejected 50 feet. She was hypotensive and hypoxic on scene with concern for head injury with a GCS of 7. She is clearly in shock on arrival with weak pulses, clammy skin, and a BP of 80/50mmHg, HR 140, sats 85%.  She is intubated, a chest tube is placed on the left (with improvement in O2 sats to 95%), and a pelvic binder is placed for suspected pelvic fracture. eFast demonstrates free fluid in the pelvis. Massive Transfusion Protocol (MTP) has been activated appropriately, and despite rapid delivery of 4 units Packed Red Blood Cells (PRBCs), 2 units of Fresh Frozen Plasma (FFP) and 1 pack of Platelets, she remains hypotensive, with presumed hemorrhagic shock. The patient is destined for the OR, but you ask yourself, in traumatic hemorrhagic shock, is there a role for vasoactive agents?

REBEL Review 91: Management of Vasopressor Extravasation

Created December 8, 2019 | Procedures and Skills | DOWNLOAD