Assessment of ventilation in low-resource healthcare settings: Montserrado County, Liberia—2022−2023

Abstract

Background: Mitigating the risk of nosocomial respiratory disease transmission in the healthcare facilities of low- and middle−income countries (LMICs) poses unique challenges because mechanical ventilation and mixed−mode strategies are often unavailable. Carbon dioxide (CO2) can serve as a proxy for ventilation and, hence, airborne infectious disease transmission risk in naturally ventilated spaces. We assessed the adequacy of ventilation in Liberian hospitals. Methods: We sampled 3 hospitals, both urban and rural, in Montserrado County, Liberia. Moreover, 3 CO2 meters were concurrently utilized to measure CO2 levels at a 1-meter height in every patient-care room in each facility. We recorded temperature, humidity, room dimensions, and number of people in the rooms. From these variables, we calculated absolute ventilation using the ASHRAE equation to determine areas with the highest risk of nosocomial respiratory disease transmission. We also recorded qualitative observations about the sampled spaces. Results: From August 2022 to February 2023, 39 rooms in 3 healthcare facilities were sampled. Initial quantitative findings show that only 8 rooms (21%) met the WHO-recommended ventilation rate of 60 L per second per person. The average ventilation rate per person in the adequately ventilated settings was 86 L per second per patient, compared to 19 liters per second per patient in inadequately ventilated rooms. Additionally, 467 ppm mean CO2 was noted in well-ventilated rooms compared to 895 ppm mean CO2 in inadequately ventilated rooms.