Thiocyanate Accumulation in Critically Ill Patients Receiving Nitroprusside Infusions

Area of Science:

• Pharmacology
• Clinical Toxicology

Background:

• Nitroprusside is a potent vasodilator used in critical care.
• Nitroprusside metabolism can lead to cyanide and thiocyanate production.
• Thiocyanate accumulation may pose a risk of toxicity in intensive care unit (ICU) patients.

Purpose of the Study:

• To evaluate thiocyanate concentrations in ICU patients receiving nitroprusside.
• To identify factors associated with thiocyanate accumulation.
• To assess the impact of sodium thiosulfate coadministration on thiocyanate levels.

Main Methods:

• Retrospective analysis of critically ill adults receiving nitroprusside.
• Comparison of patients with and without thiocyanate accumulation (≥30 µg/mL).
• Statistical analysis including Spearman correlation and multivariate regression.

Main Results:

• 16% of patients (14/87) showed thiocyanate accumulation.
• Accumulation was associated with higher cumulative nitroprusside and sodium thiosulfate doses, and longer infusion durations.
• Higher thiocyanate concentrations were observed with sodium thiosulfate coadministration.
• Cumulative nitroprusside dose was independently associated with thiocyanate accumulation.

Conclusions:

• Cumulative nitroprusside dose is a key factor in thiocyanate accumulation.
• Despite elevated levels in some patients, no clinical toxicity was observed.
• Routine thiocyanate monitoring is advisable for patients on high-dose nitroprusside therapy.