Oral Liquid Controlled Drug Discrepancies Caused by ENFit™ Enteral Syringes and Adapters

Abstract

Background:

Accurate recording of Controlled Drug (CD) transactions is a key legislative and professional responsibility in Australian hospitals. Following the introduction of ENFit™ enteral systems, designed to reduce wrong-route medication administration errors, discrepancies in oral liquid CD balances continued to be reported. Residual liquid that remained in ENFit™ syringes and multi-dose bottles after the withdrawal process was suggested as a contributing factor.

Objective:

To estimate the amount of oral liquid loss associated with the use of ENFit™ enteral syringes and bottle adapters, and to explore potential implications for oral liquid CD documentation accuracy.

Methods:

A laboratory-based simulation study was conducted to model the use of ENFit™ enteral syringes (1, 2.5, 5, and 10 mL) and ENFit™ bottle adapters during repeated withdrawals from 100 mL sample bottles. Simple syrup B.P. was selected for its viscosity comparable to that of oral liquid medications. Syringes and bottles were weighed before and after each withdrawal using a calibrated scale, and the weight of residual liquid was converted to volume using the density of simple syrup (1.27 g/mL). The viscosity of the test liquid was measured and compared with that of two commonly used oral liquid CDs.

Results:

Across 184 withdrawals, the mean (SD) total volume loss per 100 mL sample was 5.17 mL (0.63), representing a 4.5% to 5.9% discrepancy. Both the number of withdrawals and the syringe size correlated with greater liquid loss. The 10 mL syringes produced the highest loss per withdrawal, while 5 mL syringes produced the largest total loss due to a greater number of withdrawals.

Conclusions:

This study demonstrated a consistent, measurable loss of oral liquid CD (approximately 5%) when using ENFit™ enteral syringes and adapters, even under controlled conditions and when correct withdrawal technique was used. These losses may contribute to minor but recurring CD discrepancies in clinical practice. Healthcare organizations should consider these findings when developing policies for oral liquid CD handling and balance reconciliation. Strategies like correct device fit, unit-dose packaging, and gravimetric verification may improve accuracy, reduce discrepancy investigations, and enhance CD recording compliance.