ECMO ECMO Pharmacology and Drug Management 1 — Questions and Answers
Question 1: Which pharmacokinetic property makes a drug most susceptible to sequestration in an ECMO circuit?
- High water solubility and low protein binding
- High lipophilicity and high protein binding (Correct answer)
- Small molecular weight and rapid renal clearance
- Low volume of distribution and neutral pH
Correct answer: High lipophilicity and high protein binding
Lipophilic, highly protein-bound drugs bind to PVC tubing and the oxygenator membrane, significantly increasing apparent volume of distribution.
Question 2: Which antibiotic requires the most aggressive therapeutic drug monitoring (TDM) in ECMO patients due to significant circuit sequestration?
- Piperacillin-tazobactam
- Azithromycin
- Vancomycin (Correct answer)
- Metronidazole
Correct answer: Vancomycin
Vancomycin is highly protein-bound and binds to ECMO circuit components, necessitating TDM to ensure therapeutic levels.
Question 3: Which antifungal agent demonstrates clinically significant sequestration in ECMO circuits due to its lipophilic properties?
- Fluconazole
- Micafungin
- Anidulafungin
- Voriconazole (Correct answer)
Correct answer: Voriconazole
Voriconazole is highly lipophilic and binds extensively to ECMO circuit materials, requiring dose escalation and TDM.
Question 4: What is the preferred alternative anticoagulant for ECMO patients diagnosed with heparin-induced thrombocytopenia (HIT)?
- Warfarin
- Fondaparinux
- Bivalirudin (Correct answer)
- Rivaroxaban
Correct answer: Bivalirudin
Bivalirudin is a direct thrombin inhibitor that does not cross-react with HIT antibodies and is the preferred heparin alternative during ECMO.
Question 5: Fentanyl is significantly sequestered in ECMO circuits primarily because it is:
- Renally cleared and water-soluble
- Highly lipophilic with high protein binding (Correct answer)
- A small molecular weight hydrophilic compound
- Metabolized by circuit enzymes
Correct answer: Highly lipophilic with high protein binding
Fentanyl's high lipophilicity and protein binding cause it to adsorb onto ECMO tubing and the oxygenator, reducing effective plasma concentrations.
Question 6: Which vasopressor is considered first-line for maintaining mean arterial pressure (MAP) in VA-ECMO patients with vasodilatory shock?
- Dopamine
- Epinephrine
- Norepinephrine (Correct answer)
- Phenylephrine
Correct answer: Norepinephrine
Norepinephrine is the first-line vasopressor in VA-ECMO due to its potent alpha-adrenergic vasoconstriction with modest beta-1 activity.
ECMO ECMO Pharmacology and Drug Management 1
Which pharmacokinetic property makes a drug most susceptible to sequestration in an ECMO circuit?