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

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

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

Hospitals in Bong and Montserrado Counties, Liberia.

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.

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

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.

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.

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