Q: Lorazepam is one of the most common drug for sedation in ICU. Vehicle to transport this drug in IV infusion is Propylene Glycol. With high dose and prolong infusion of Lorazepam, Propylene Glycol toxicity is a huge concern. What 2 tests may help in ruling out Propylene Glycol toxicity if suspected?

Answer:

• Osmolal gap
• Hyperlactatemia

Risk for Propylene Glycol Toxicity is high in patients with renal insufficiency particularly in patients with a creatinine clearance of 30 ml/minute or below. 

Reference:

Reynolds HN, Teiken P, Regan ME, et al. Hyperlactatemia, increased osmolar gap, and renal dysfunction during contin-uous lorazepam infusion. Crit Care Med 2000;28:1631-4.