NAPLEX Question of the Week: Going Deep with DVTs

This week's question will challenge your knowledge of the basics of VTE prophylaxis.
NAPLEX Question of the Week: Going Deep with DVTs

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RK is a 45-year-old male who is admitted to the ICU for septic shock. He is currently intubated and initiated on Zosyn 4.5gm IV q6h and norepinephrine 0.05 mcg/kg/min (after appropriate volume resuscitation).

PMH: Type 2 diabetes mellitus, hypertension, dyslipidemia

Home Medications: Metformin 1000mg PO BID (held on admission), Atorvastatin 40 mg PO daily, Zestril 40mg PO daily (held on admission), Metoprolol Tartrate 25mg PO daily (held on admission)

Pertinent Labs/Vitals:

Na: 137mg/dL, K: 4.3meq/L, Phosphate: 3 meq/L, WBC: 10.4 X 103/µL , SCr: 0.9 mg/dl (baseline 0.8 mg/dl), , Lactate 3 mmol/L

BP: 95/70 mmHg, HR 95 bpm, RR 13 rpm, Temp 100.4°F

Weight – 110 kg, Height 64 inches, BMI 41.6 kg/m2

While on rounds, the intern wants to start this patient on pharmacologic VTE prophylaxis. She writes an order for “Heparin 5000 units IV Q24h”. Select the most appropriate intervention to make.

A. Change the route of administration to subcutaneous; keep the same dose and dosing interval

B. Change the route of administration to subcutaneous; keep the same dose and increase the frequency to q8h

C. Keep the same route of administration; increase the dose to 7500 units and increase the frequency to q8h

D. Verify the order as written

Rationale with correct answers

Brand/generic: Lisinopril (Zestril), Metoprolol Tartrate (Lopressor), Metformin (Glucophage), Atorvastatin (Lipitor)

Septic shock is a life threating syndrome that is caused by a dysregulated host response to infection with persistent hypotension requiring vasopressors to maintain a MAP >65 despite adequate volume resuscitation. Patients with confirmed septic shock are treated in the ICU and are immobilized which often requires mechanical and pharmacologic VTE prophylaxis if no contraindications. Dosing varies significantly with these agents as well as route of administration depending on whether using for prophylaxis or treatment. Let’s review our question to see the correct answer.

Answer A is incorrect. Changing the route of administration to subcutaneous is appropriate in this patient because he is receiving VTE prophylaxis and the use of IV is used for treatment. Keeping the same dose and dosing interval would be inappropriate since a standard dosing regimen is 5000-7500 units SQ q8h-12h.

Answer B is correct. This change would be the correct regimen. Due to our patient’s obesity (BMI >30), increasing the dose to 7500 units would be an appropriate consideration in some patients. In addition, it would not be unreasonable to dose the patient q12h instead of q8h as this is within the normal dosing range for VTE prophylaxis.

Answer C is incorrect. Unfractionated Heparin is typically administered IV only for treatment of DVT/PE, not prophylaxis. In addition, patients may receive unfractionated heparin IV in the management of acute coronary syndromes, such as myocardial infarction or unstable angina. 

Answer D is Incorrect. Verifying this order would underdose this patient increasing their risk for development of a DVT/PE. The IV route of administration is not appropriate as detailed in answer C.


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