Bacterial contamination and greenhouse gas emissions A randomised study of reuse versus single-use of infusion-set components for intravenous anaesthesia

BACKGROUND Reusing anaesthesia infusion-set components may reduce the climate impact from plastic waste and discarded medications. Infusion-set contents can be shielded from patient contact by single use of an infusion line fitted with dual antireflux valves, preventing retrograde entry of microorganisms, and eliminating the risk for patient-to-patient cross-contamination. However, infusion-set contamination from compromised aseptic handling could affect quality of care. INTERVENTIONS To determine the prevalence of infusion-set bacterial contamination and compare the climate effects, we randomised operating rooms scheduled for total intravenous anaesthesia to handle procedures by infusion-set reuse or single-use. Both methods used dual single-use antireflux valves. OUTCOMES The primary outcome was infusion-set bacterial contamination assessed by aerobic culture of infusion-set fluid collected after each procedure. The secondary outcome was CO2 emissions (CO2-eq) estimated by life cycle assessment of component and medication use. To assess feasibility of detecting an inter-method difference in bacterial contamination, an interim analysis was planned after including at least 150 procedures per group. RESULTS After allocating 54 operating rooms per method, 189 and 159 procedures of reuse and single use were included. Reuse permitted a median of three procedures per infusion set (range 1 to 8). Positive cultures occurred in two procedures per method [mean (95% CI)]; prevalence 1.15% (0.03 to 2.27); relative risk of reuse versus single use 0.84 (0.12 to 5.93), P = 0.861. As prespecified, inclusion was stopped due to futility. The median (95% CI) per-procedure climate emissions were 0.43 (0.41 to 0.47) and 1.39 (1.37 to 1.40) kg CO2-eq for reuse and single-use respectively; difference -0.96 (-0.99 to -0.93), P < 0.0005. The main sources for climate emissions were production of infusion-set components and waste handling. CONCLUSIONS We conclude that the prevalence of bacterial contamination was low for both methods. A much larger study would be needed to detect an inter-method difference. Reuse of infusion-set components allowed significantly reduced intravenous anaesthesia climate emissions.