Is the ACT two minutes after heparin injection reliable?

Area of Science:

• Cardiovascular Surgery
• Anesthesiology
• Pharmacology

Background:

• Traditional activated clotting time (ACT) measurement after heparin administration in cardiac surgery occurs 5 minutes post-injection.
• There is a growing need to shorten the waiting period for ACT verification.
• This study evaluates the reliability of earlier ACT measurements.

Purpose of the Study:

• To determine if ACT measurements at 1, 2, 3, and 4 minutes post-heparin injection are as reliable as the standard 5-minute measurement.
• To assess the clinical relevance of reduced waiting times for ACT assessment in cardiac surgery.

Main Methods:

• Fifty adult patients undergoing routine cardiac surgery were included.
• Unfractionated porcine heparin was used for anticoagulation.
• ACT was measured using 5 Hemochron® Jr. machines at 1, 2, 3, 4, and 5 minutes post-heparin injection.
• Full heparinization was defined as ACT > 400 seconds.

Main Results:

• At 1 and 2 minutes, 94% of ACT measurements exceeded 400 seconds.
• ACT values measured at 2 minutes correlated well with mean 1-5 minute values.
• While statistically significant differences in ACT values were observed at 1, 2, and 3 minutes compared to 5 minutes, the clinical relevance was minimal.

Conclusions:

• Measuring ACT at 2 minutes post-heparin administration is a reliable alternative to the traditional 5-minute measurement.
• The slight variations in ACT values at earlier time points have little to no clinical impact.
• Reducing the ACT measurement time to 2 minutes allows for adequate heparin distribution and verification.