Supplemental oxygen in Queen Elizabeth Central Hospital Malawi: a prospective cohort study of patients admitted to medical wards

Background: Oxygen is designated an essential drug by the World Health Organisation, and reduces mortality in hypoxic patients. In low-resource settings the provision of oxygen seldom meets its demand. This study describes the predictors and observed time-course of hypoxaemia in order to inform needs assessments for oxygen in hospitals in low and middle income countries. Methods: A prospective cohort study of adults with hypoxaemia admitted to medical wards of a teaching hospital in Malawi between January and March 2020. Vital signs and oxygen therapy were recorded daily. We analysed outcomes (death, discharge from hospital or ongoing inpatient care at 14 days after admission) using Kaplan-Meier and Cox regression time-to-event analysis. Results: 33 patients were recruited with median age 45 years (IQR 33-61), and 13 (39%) female. Median pre-treatment oxygen saturations were 84% (IQR 76-87%). Oxygen delivery devices were often shared with other patients (n=10, 33%) and the flow rate was often unknown (n=14, 47%), mostly because of broken equipment (n=8, 57%). Median duration of oxygen therapy was 3 days (IQR 1-7). Death occurred in 16 (49%). Hazard ratios for short oxygen therapy were reduced in patients who had a chest radiograph performed (HR 0.08, 95% CI 0.02–0.30), in ex-smokers (HR 0.01, 95% CI 0.00-0.22) and in never smokers (HR 0.03, 95% CI 0.00 – 0.78). Conclusions: Delivering oxygen therapy in lower-middle income countries is challenging; broken equipment and shared delivery devices prevented titration of flow rates. Patients were relatively young and at a high risk of death. Patients with a chest radiograph received oxygen for longer than those without. Knowledge of oxygen therapy durations will allow careful assessment of the oxygen supply need at the hospital level.