Comparing Three Methods for Dilution Accuracy of Intravenous Preparations

Area of Science:

• Pharmaceutical Sciences
• Clinical Pharmacy Practice
• Medication Safety

Background:

• Intravenous medication dilutions can exhibit inaccuracies.
• The method of mixing is a significant factor influencing dilution accuracy.

Purpose of the Study:

• To evaluate the impact of different dilution techniques on medication accuracy.
• To identify optimal methods for preparing intravenous medication dilutions at the bedside.

Main Methods:

• Nurses prepared glucose in saline dilutions using a random factorial design.
• Tested factors included dilution volume (large vs. small), mixing method (shaking vs. inversion), and number of maneuvers (3 vs. 10).
• Accuracy was assessed by comparing measured concentration (Cmes) to expected concentration (Cexp).

Main Results:

• Measured concentrations ranged from 89.5% to 123.6% of expected concentrations.
• Dilutions were more accurate when using a large volume (98.4% vs. 106.5% of Cexp).
• Mixing by inversion yielded higher accuracy (100.6% vs. 104.6% of Cexp) compared to shaking.

Conclusions:

• Inversion mixing and dilution in large volumes improve accuracy for bedside medication preparation.
• The number of mixing maneuvers (3 vs. 10) did not significantly affect accuracy.
• Findings suggest simpler, more accurate bedside dilution protocols are achievable.