Reducing propofol waste during TIVA by pre-operative estimation of requirement: A single-center retrospective analysis

Abstract

Objective

To evaluate whether estimating propofol requirement before surgery using a target-controlled infusion (TCI) model-based algorithm could reduce waste whilst maintaining workflow.

Design

Retrospective cohort study with in silico TCI-TIVA simulations using the Eleveld model at fixed effect-site targets (Cet 2.5–4.0 μg.ml⁻¹) or a Cet corresponding to an estimated BIS of 45 (EC_BIS45). Monte-Carlo simulation examined uncertainty in surgical duration estimates.

Setting

University tertiary care provider.

Patients

229 adult patients undergoing general anesthesia with conventional propofol TIVA with manually adjusted infusion rate.

Measurements

Primary endpoint: predicted propofol amount for TCI and waste associated with three drawing-up strategies (50 ml vial only, 20 ml vial only, and vial combination based on estimated requirements). Secondary endpoint: relative number of syringe changes.

Main results

Propofol requirements predicted using Cet 3.0 and EC_BIS45 were similar to actual consumption. Algorithm-guided drawing-up produced significantly lower predicted waste than conventional TIVA practice (p < 0.0001, CI = −61.0 to −27.0 mg/procedure for Cet 3.0; p = 0.001, CI = −60.0 to −26.7 mg/procedure for EC_BIS45), comparable to the 20 ml vial-only strategy but requiring fewer syringe changes. Waste remained significantly lower despite surgical duration estimation errors up to 20% for Cet 3.0 (p = 0.007) and 30% for EC_BIS45 (p = 0.01).

Conclusions

Using the Eleveld TCI model to estimate pre-operative propofol requirements could significantly reduce waste and avoid excessive syringe changes, even when surgical duration is uncertain.