The Epidemiology and Impact of Hypoxemia in Sub-Saharan Africa: Prevalence, Practices, and Outcomes.

Abstract

Rationale: The epidemiology of hypoxemia in sub-Saharan Africa is largely unknown. Objectives: To determine the prevalence, clinical care, and outcomes for hospitalized hypoxemic adults in sub-Saharan Africa. Methods: We prospectively screened all adults admitted to five hospitals in Kenya, Malawi, and Rwanda over four months; identified those with hypoxemia (defined as oxygen saturation as measured by pulse oximetry [Sp_O2] < 90% or receipt of oxygen therapy); and followed hypoxemic patients to discharge. Results: Of the 24,724 adult patients admitted, 1,739 (7%) were hypoxemic on admission. The median imputed ratio of arterial oxygen pressure to fraction of inspired oxygen (Pa_O2 :FI_O2) was 168. Of all patients screened, 4,546 (18%) had complete oxygenation domains (Sp_O2, device, and quantity) documented in their charts on admission. Among hypoxemic patients, 44% of in-hospital days (6,890 of 15,553) had chart documentation of all three oxygenation domains. Of 1,508 unique hypoxemic patients, 770 (51%) had at least one day with subtherapeutic oxygen (Sp_O2 < 90%). Of patient-days with patients on oxygen therapy, 84% indicated supratherapeutic oxygen therapy (Sp_O2 > 94%). Of all hypoxemic adults, 35% died in the hospital. Sixteen percent of patients were mechanically ventilated during their stays, and in-hospital mortality in this subgroup was 49%. Conclusions: Hypoxemia is common and associated with high mortality at five referral hospitals in three countries in sub-Saharan Africa. Monitoring and titration practices for oxygen therapy are inconsistent. Subtherapeutic and supratherapeutic oxygen therapy are common. Mortality is high among the few patients who receive mechanical ventilation. These findings suggest the urgent need to study interventions to improve survival for hypoxemic patients in sub-Saharan Africa. Prioritized investigations include the development and implementation of oxygen monitoring and titration protocols, as well as studies of advanced oxygen therapies other than mechanical ventilation.