Appendix 3: Critical Care: Patient Assessment and Pharmacotherapy

Absorption

↓ Absorption

Perfusion abnormalities

Decreased GI motility

Altered gastric pH

Bowel wall edema

Drug–nutrient interactions

Enteral, intramuscular, or subcutaneous drugs

Itraconazole (capsules need an acidic medium for absorption), phenytoin (significant drug–nutrient interactions), subcutaneous enoxaparin (incompletely absorbed in the setting of vasopressors and edema)

Distribution

↑ Vd

Large-volume resuscitation

Capillary leak syndrome

Ascites

Mechanical ventilation

Hydrophilic drugs

Aminoglycosides, beta-lactams, daptomycin, hydromorphone, morphine, vancomycin

Hypoalbuminemia

Albumin-bound drugs

Amiodarone, ceftriaxone, midazolam, morphine, phenytoin, propofol, valproic acid, warfarin

Extracorporeal circuits with expansive surface area (ECMO)

Lipophilic drugs

Diazepam, fentanyl, fluoroquinolones, macrolides, midazolam, propofol

↓ V_d

Decreased α1-acid glycoprotein

Drugs bound to α1-acid glycoprotein

Azithromycin, carvedilol, fentanyl, lidocaine, olanzapine, phenobarbital

Metabolism

↑ Metabolism

Hepatic enzyme induction

Augmented hepatic blood flow

Flow-dependent drugs (hepatic extraction ratio >0.7)

Propofol, midazolam, morphine, metoprolol

↓ Metabolism

Hepatic enzyme inhibition

Decreased hepatic blood flow

Flow-independent drugs (hepatic extraction ratio <0.3)

Warfarin, diazepam, phenytoin

Excretion

↑ Clearance

Augmented renal clearance

Extracorporeal removal

Renally eliminated medications

Beta-lactam antibiotics, vancomycin, enoxaparin, gabapentin, levetiracetam

↓ Clearance

Acute kidney injury

Nephrotoxic medications

Aminoglycosides, NSAIDs, antivirals, contrast

Feeding

American Society for Parenteral and Enteral Nutrition

Replenish nutritional stores

Maintain gut function

Data suggest reductions in infectious complications (eg, pneumonia) and mortality with enteral nutrition

Enteral nutrition formulas

Gastric motility agents

Parenteral nutrition

Analgesia

Maintain patient comfort due to interventions, procedures, or chronic pain

Analgesia-first approach (ie, analgosedation) to limit sedative agents

Acetaminophen

Neuropathic-acting agents

Nonsteroidal anti-inflammatory drugs

Opioids

Sedation

Maintain patient comfort due to interventions or procedures

Respiratory depression for mechanical ventilation and severe respiratory failure

Lightest level of sedation possible preferred; daily sedation interruption

Benzodiazepines

Dexmedetomidine

Ketamine

Propofol

Thromboembolic prophylaxis

Reduction in incidence of venous thromboembolism

Balance with risk of bleeding

Enoxaparin

Heparin

Head-of-bed elevation (45^o)

Reduces aspiration events and pneumonia

N/A

Stress Ulcer prophylaxis

Reduction in stress-related mucosal damage (eg, gastrointestinal bleeding)

Risk based on risk factors related to bleeding (eg, coagulopathy)

Data inconsistent on benefits

Histamine₂-receptor antagonists

Proton pump inhibitors

Glycemic control

Prevent hypoglycemia and hyperglycemia in setting of critical illness

Studies indicate improved mortality, length of stay, and reduced infections by prevention hyperglycemia

Hypoglycemia associated with increased mortality

Goal range dependent on population (eg, cardiac)

Basal insulin

Insulin infusion

Sliding scale insulin

Spontaneous breathing trial

Limits duration of mechanical ventilation

Limits amount of sedatives a patient is exposed to

Decreasing analgesia/Sedation

Bowel regimen

Prevention of ileus with immobility or ...