The Impact of a Novel Operational Readiness Response Model on the Environmental Cleanliness of Emergency Ambulances

Objectives: Environmental cleanliness of emergency ambulances may be associated with increased risk of healthcare acquired infection (HAI). Surface cleanliness, measured using adenosine triphosphate (ATP) testing, has been demonstrated to correlate with potentially harmful levels of microbial pathogens. In most ambulance services, environmental cleanliness of ambulances and the equipment within them is the responsibility of paramedics. In 2016 NSW Ambulance introduced the Make Ready Model (MRM), in which ambulances are systematically cleaned by non-clinical support staff at the end of each shift. This prospective study aimed to 1) provide a baseline level of ambulance cleanliness; and 2) compare the MRM to a standard cleaning model (SCM). Methods: A prospective comparative study was conducted comparing cleanliness of ambulances in the SCM to those in the MRM. Adenosine-triphosphate (ATP) bioluminescence testing was performed in a pseudo-randomised sample of ambulances. Six 'high touch' areas within each ambulance were systematically sampled. Testing occurred without warning to operational staff. The primary outcome was 'overall bioburden' (OB)' measured in radiant light units ('RLU'). Non-parametric tests were used to assess differences in RLU values between each of the test points, while Poisson multivariate regression was used to compare median overall bioburden between the two groups, adjusting for the confounder variable of 14-day ambulance workload. Results: Sixty-eight ambulances were sampled, 32 from the SCM and 36 from the MRM. Median surface bioburden was significantly lower in the MRM for four of the six test points (preparation table, mobile data terminal, stretcher handles and steering wheel). For the primary outcome of overall bioburden, the unadjusted MRM OB was 35% lower than for the SCM group (RR 0.65 (0.64-0.66; p < 0.01)). After adjusting for the significant confounding variable of 14-day workload, the OB was 38% lower for the MRM group (ARR 0.68 (0.61-0.63; p < 0.001)). Conclusion: The innovative MRM cleaning system was associated with significantly improved cleanliness in frontline emergency ambulances. The magnitude of improvement in cleanliness suggests this cleaning model has the potential to make a major contribution to infection control strategies in paramedicine. Future research should focus on cost effectiveness of the MRM and its applicability to regional and remote ambulance service operations.