Effectiveness and acceptability of ventilation modifications in healthcare facilities, Liberia 2022-2023.

Objective: To evaluate the effectiveness and acceptability of ventilation interventions in naturally ventilated hospitals in Liberia.

Design: Difference-in-differences analysis of pre- and post-air changes per hour of intervention and control spaces.

Setting: Hospitals in Bong and Montserrado Counties, Liberia.

Participants: Seventy patient care spaces were evaluated at baseline. Six spaces underwent physical intervention modifications, while 2 spaces were assessed for indirect effects and 2 others used as controls. Healthcare workers were interviewed to assess ventilation knowledge and acceptability.

Interventions: Ventilation interventions included the installation of window screens, louvered doors and windows, and wind turbines.

Methods: We measured carbon dioxide levels with portable meters and documented persons per room to estimate per-person ventilation rates in both L/s/person for the initial assessment and air changes per hour (ACH) in the intervention. Measurements were taken in patient care spaces in 7 hospitals in Liberia. Healthcare worker acceptability was evaluated via structured interviews.

Results: Two-thirds (46/70) of patient care spaces were below the WHO-recommended ventilation threshold of 60 L/s/person. Six spaces underwent ventilation interventions, including placement of window screens (3), wind turbines (2), and louvered doors and windows (1), with 2 additional spaces being indirectly affected by these interventions and 2 more spaces serving as controls. Ventilation improved by an average of 2 ACH in the spaces with wind turbines and louvered doors and windows. Overall acceptability of the interventions was high.

Conclusions: Implementing interventions to improve ventilation in naturally ventilated healthcare facilities is efficacious, feasible, and acceptable, though longer-term evaluations should assess sustainability.