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MODULE 6, PART 2: CRITICAL CARE (ICU) PHARMACY WORKFLOWS
Section 7: The “Big Three” Prophylaxis Bundles
This masterclass focuses on the essential, everyday pharmacist interventions that prevent common ICU complications: blood clots, stress ulcers, and ventilator-associated pneumonia. Mastering these is as crucial as managing any code.
PART 7.1
Venous Thromboembolism (VTE) Prophylaxis
The Pharmacist’s First Daily Check
Of all the preventative therapies in the ICU, VTE prophylaxis is arguably the most important. Critically ill patients are in a profoundly hypercoagulable state due to systemic inflammation (Virchow’s triad), while at the same time being completely immobile. This is a perfect storm for the development of deep vein thrombosis (DVT) and pulmonary embolism (PE). A preventable, hospital-acquired VTE is considered a major patient safety failure. As the pharmacist, your first task every single day, on every single patient, is to ask and answer the question: “Is this patient on appropriate VTE prophylaxis?” This daily check is a core responsibility of the ICU pharmacist.
Retail Pharmacist Analogy: The Monthly Refill Check
In your retail practice, you have a systematic way of checking for adherence. When a patient with hypertension only refills their lisinopril every 45 days, you don’t ignore it. You recognize this as a safety risk, a gap in therapy that could lead to a stroke. You investigate, counsel the patient, and contact the provider if needed.
VTE prophylaxis in the ICU is the same concept, just on a 24-hour cycle. A critically ill patient without VTE prophylaxis is like that hypertensive patient who is out of their lisinopril—they have a dangerous gap in their preventative care. Every morning, you are doing your “refill check.” You scan your patient list, and for any patient not on prophylaxis, you must ask “Why?” Is it intentional (e.g., they are actively bleeding)? Or was it an oversight? Your systematic daily review is the safety net that catches these gaps before a clot can form.
Pharmacologic vs. Mechanical Prophylaxis
VTE prevention is achieved through two primary modalities. For most patients, pharmacologic prophylaxis is superior and is the standard of care. Mechanical prophylaxis is reserved for patients who have an active, high-risk contraindication to anticoagulants.
| Modality | Examples | Mechanism | When to Use |
|---|---|---|---|
| Pharmacologic | Subcutaneous Unfractionated Heparin (UFH) Subcutaneous Enoxaparin (Lovenox®) |
Inhibits the coagulation cascade (primarily Factor Xa and thrombin) to prevent thrombus formation. | Standard of care for almost all ICU patients. |
| Mechanical | Sequential Compression Devices (SCDs) Intermittent Pneumatic Compression (IPC) devices |
Inflatable sleeves on the legs that simulate the muscle-pumping action of walking, preventing venous stasis. | Used ONLY when pharmacologic prophylaxis is absolutely contraindicated (e.g., active major bleeding, severe thrombocytopenia [<50,000/mm³], impending major surgery like neurosurgery). |
Heparin vs. Enoxaparin: The Pharmacist’s Choice
The two workhorses of VTE prophylaxis are UFH and the low-molecular-weight heparin (LMWH) enoxaparin. As the pharmacist, you are the expert who guides the selection and dosing of these agents.
| Feature | Unfractionated Heparin (UFH) | Enoxaparin (Lovenox®) |
|---|---|---|
| Standard Dosing | 5000 units SUBCUT every 8 hours (TID) | 40 mg SUBCUT every 24 hours (QD) |
| Elimination | Reticuloendothelial system (non-renal) | Renal |
| Renal Adjustment | None required. | Required if CrCl < 30 mL/min. Dose is reduced to 30 mg SUBCUT every 24 hours (QD). |
| Reversibility | Short half-life. Fully reversible with protamine. | Longer half-life. Partially reversible with protamine. |
| Pharmacist’s Choice | Drug of choice in patients with severe renal dysfunction (CrCl < 30 mL/min) or those at high risk of needing an urgent procedure. | Often preferred in stable patients with normal renal function due to once-daily dosing and a more predictable response. |
Clinical Pearl: The Renal Dosing Intervention
Screening for appropriate renal dosing of enoxaparin is one of your most frequent and important interventions. A common error is for a patient to be started on enoxaparin 40 mg daily, and then develop an acute kidney injury (AKI), dropping their creatinine clearance below 30. The team may miss this change. It is your job to catch it during your daily review and recommend the dose be adjusted to 30 mg daily or, even better, to switch to heparin 5000 units TID, which does not require renal adjustment and is safer in the setting of fluctuating renal function. This is a critical safety intervention.
PART 7.2
Stress Ulcer Prophylaxis (SUP)
The Art of Initiation and De-Prescribing
Critically ill patients are at risk for developing stress-related mucosal disease (SRMD), or stress ulcers. The profound physiological stress of their illness shunts blood away from the gut, impairing the mucosal barrier and leaving the stomach lining vulnerable to acid damage. A clinically significant upper GI bleed from a stress ulcer is a serious complication. Stress Ulcer Prophylaxis (SUP) involves using acid-suppressive medications to reduce this risk. However, unlike VTE prophylaxis, not every ICU patient needs SUP. In fact, overuse of these agents is a major problem, and the pharmacist plays a key role in both appropriate initiation and, crucially, de-prescribing.
Key Indications for SUP
The current guidelines recommend SUP only for patients with major risk factors for clinically significant bleeding. Your job is to know these indications by heart so you can identify who needs therapy and who does not.
| Risk Factor | Rationale | Pharmacist’s Action |
|---|---|---|
| Mechanical Ventilation > 48 hours | The strongest predictor of stress ulceration. | Strongly recommend initiating SUP. |
| Coagulopathy (Platelets < 50k, INR > 1.5, or aPTT > 2x normal) | Inability to form a clot if a small erosion begins to bleed. | Strongly recommend initiating SUP. |
| History of GI bleed within 1 year | Pre-existing mucosal vulnerability. | Recommend SUP. |
| Traumatic brain injury, traumatic spinal cord injury, or severe burn | High-stress states with known association to ulceration. | Recommend SUP. |
| High-dose corticosteroid therapy (>250mg hydrocortisone equivalent) | Steroids impair mucosal healing. | Consider SUP, especially if other risk factors are present. |
Importantly, patients who do not have these risk factors, such as a routine post-operative patient or a patient admitted for DKA who is extubated within a day, do NOT require SUP.
PPIs vs. H2RAs: The Pharmacist’s Choice
| Agent Class | Examples | Pros | Cons |
|---|---|---|---|
| Proton Pump Inhibitors (PPIs) | Pantoprazole 40 mg IV/PO daily Esomeprazole 40 mg IV/PO daily |
More potent acid suppression. May be more effective at preventing bleeding. Once-daily dosing. | Associated with a higher risk of hospital-acquired pneumonia and C. difficile infection. More expensive. |
| H2-Receptor Antagonists (H2RAs) | Famotidine 20 mg IV/PO BID | Less potent acid suppression, may have a lower risk of pneumonia/C. diff. Less expensive. | Tachyphylaxis (loss of effect) can occur after several days. Requires renal dose adjustment. Twice-daily dosing. |
The Pharmacist’s Role in De-prescribing: Stopping the “Ritual”
In your retail practice, you often see patients who were started on a PPI in the hospital and were never taken off it. This is a massive problem, and it starts in the ICU. SUP is often continued out of habit long after the indication for it is gone. This inappropriate continuation exposes patients to the risks of pneumonia, C. difficile, and fractures without any benefit.
Your most important role in SUP management is de-prescribing. Every day, you must ask: “Does my patient still have an indication for SUP?”
- Has the patient been extubated for > 48 hours?
- Has their coagulopathy resolved?
- Are they eating a regular diet? (Enteral nutrition is protective of the gut mucosa).
If the answer to these questions is yes, the SUP should be discontinued. You must be the proactive voice that contacts the team and says, “The patient was extubated yesterday and is starting tube feeds. Per guidelines, we can now safely discontinue the pantoprazole.” This single intervention prevents the lifelong, inappropriate continuation of a medication.
PART 7.3
Ventilator-Associated Pneumonia (VAP) Prophylaxis
The Power of Non-Pharmacologic Bundles
Ventilator-associated pneumonia is a lung infection that develops in a patient who has been on a mechanical ventilator for at least 48 hours. The endotracheal tube, while life-saving, bypasses the body’s natural airway defenses and provides a direct conduit for bacteria to enter the lungs. VAP is associated with a significant increase in mortality and length of stay. VAP prophylaxis is not about a single drug, but a “bundle” of care practices designed to reduce the risk of infection. The pharmacist’s role is crucial, particularly in the realm of sedation management.
The VAP Prevention Bundle
This is a set of evidence-based interventions that, when performed together, dramatically reduce the incidence of VAP.
- Head of Bed Elevation: Keeping the head of the bed elevated at 30-45 degrees uses gravity to reduce the risk of aspiration of oral and gastric contents.
- Oral Care with Chlorhexidine: Regular brushing of the teeth and rinsing with chlorhexidine solution reduces the burden of pathogenic bacteria in the oropharynx, preventing them from being aspirated into the lungs.
- Daily Sedation Vacations & Spontaneous Breathing Trials: This is the most important component and where the pharmacist has the most impact.
The Pharmacist’s Role: Minimizing Sedation to Facilitate Early Extubation
The single most effective way to prevent VAP is to get the patient off the ventilator as quickly as possible. Every day a patient spends on the ventilator is another day they are at risk. Your role in VAP prevention is directly tied to your role in sedation and analgesia management (covered in Section 6). By championing the “Analgesia-First” philosophy, by advocating for light sedation targets, by avoiding benzodiazepines, and by ensuring your patient participates in a daily Spontaneous Awakening Trial (SAT), you are actively working to get that patient liberated from the ventilator sooner.
The SAT (or “sedation vacation”) involves holding all sedative infusions once a day to allow the patient to wake up. If they are comfortable and not agitated, they can then be assessed for a Spontaneous Breathing Trial (SBT), where they are allowed to breathe on their own through the ventilator circuit. If they pass the SBT, they are a candidate for extubation.
When you successfully argue to reduce a patient’s propofol infusion, allowing them to wake up and pass a breathing trial, you have just performed a critical VAP prophylaxis intervention. Your expertise in managing sedatives is the key to preventing this deadly infection.
