What is the best VTE prophylaxis for a patient with suspected septic shock in the ICU receiving high-dose norepinephrine infusion?

Best VTE Prophylaxis in Septic Shock Patient on High-Dose Norepinephrine

Enoxaparin 40 mg subcutaneously every 24 hours plus an intermittent pneumatic compression (IPC) device is the best choice for VTE prophylaxis in a patient with septic shock receiving high-dose norepinephrine. 1

Rationale for Pharmacological Prophylaxis

The 2017 Surviving Sepsis Campaign guidelines strongly recommend pharmacologic prophylaxis against venous thromboembolism (VTE) in patients with sepsis or septic shock, with specific preference for low-molecular-weight heparin (LMWH) over unfractionated heparin (UFH):

1. LMWH is recommended over UFH (strong recommendation, moderate quality evidence) 1
2. Daily subcutaneous LMWH is preferred over twice or three times daily UFH 1
3. Enoxaparin specifically has demonstrated superiority in reducing pulmonary embolism compared to UFH in critically ill patients 1

Combination with Mechanical Prophylaxis

Adding mechanical prophylaxis with an intermittent pneumatic compression device provides additional protection:

• The guidelines suggest combination pharmacologic VTE prophylaxis and mechanical prophylaxis whenever possible (weak recommendation, low quality evidence) 1
• This dual approach is particularly important in high-risk patients such as those with septic shock 1

Considerations for Patients on Vasopressors

For patients receiving high-dose norepinephrine:

• There is no specific contraindication to LMWH in patients receiving vasopressors 1, 2
• The risk of VTE in critically ill septic patients remains high despite other treatments 3
• Early VTE can occur in septic patients and is often clinically silent, making prophylaxis essential 3

Dosing Considerations

The standard dosing of enoxaparin 40 mg subcutaneously every 24 hours is appropriate for most patients with normal renal function:

• If creatinine clearance is < 30 mL/min, the guidelines recommend using dalteparin or another LMWH with low renal metabolism, or switching to UFH 1
• For obese patients (BMI ≥35 kg/m² or weight ≥150 kg), weight-based dosing may be considered 4

Why Not Other Options?

1. UFH 5000 units subcutaneously every 8 hours alone: While effective, this is inferior to LMWH based on strong evidence showing LMWH superiority in reducing pulmonary embolism risk 1

2. UFH 5000 units subcutaneously every 8 hours plus IPC: Although the combination with IPC is beneficial, UFH remains inferior to LMWH for pharmacological prophylaxis 1

3. Enoxaparin 40 mg subcutaneously every 24 hours alone: While better than UFH alone, this lacks the additional protection provided by combining pharmacological and mechanical prophylaxis 1

Potential Pitfalls and Caveats

• Monitor for bleeding: Patients with septic shock may have coagulopathy or thrombocytopenia that increases bleeding risk
• Assess renal function: Enoxaparin clearance is reduced in renal impairment; adjust or switch to UFH if creatinine clearance is <30 mL/min 1
• Reassess regularly: The patient's risk profile may change during ICU stay, requiring adjustment of prophylaxis strategy
• Consider contraindications: If severe thrombocytopenia, active bleeding, or other contraindications to pharmacological prophylaxis develop, switch to mechanical prophylaxis only 1

In conclusion, for this 37-year-old female with suspected septic shock on high-dose norepinephrine, the combination of enoxaparin 40 mg subcutaneously every 24 hours plus an intermittent pneumatic compression device represents the optimal VTE prophylaxis strategy based on current guidelines and evidence.