Prevalence of undiagnosed hypoxia in an under-resourced district hospital in Zambia

Background: Untreated hypoxia is a life-threatening condition. In adequately resourced clinical environments, diagnosis via pulse oximetry and treatment with supplemental oxygen are the universally accepted standard of care. Unfortunately, pulse oximetry is rarely utilized in under-resourced hospitals in low-income countries and the prevalence of undiagnosed hypoxia in such environments is largely unknown.

Methods: This cross-sectional analysis of prevalence of undiagnosed hypoxia was conducted in Kapiri Mposhi, Zambia, at the 60-bed District Hospital, which serves a population of 320,000. The resting oxygen saturation of a consecutive sample of all adult and pediatric inpatients was measured over a four-day period in December 2008 using handheld pulse oximetry. Hypoxia was defined as SpO2 92% or less for adults, and SpO2 95% or less for children under age 12.

Results: Of 70 total patients, 9 had previously unrecognized hypoxia (13%), none of whom were receiving oxygen therapy. Pneumonia and tuberculosis were the most common diagnoses among those with hypoxia. Oximetry data changed management in 12 cases (17%), leading to application of supplemental oxygen, initiation of further diagnostic testing, prolongation of inpatient stay, or expedited discharge home.

Conclusions: Undiagnosed hypoxia was present with high prevalence in this under-resourced clinical environment. Diagnosis via pulse oximetry altered the management for a significant proportion of patients. Further investigation is warranted into the extent of undiagnosed hypoxia in other similar settings, the ability of pulse oximetry to allocate scarce resources efficiently, and the potential for impact on morbidity and mortality.