What is the role of pulse oximetry in the assessment of patients with community-acquired pneumonia in primary care?

Abstract

Community-acquired pneumonia (CAP) is a common presenting condition in primary care. Assessment of oxygenation status using pulse oximetry is increasingly available, but its precise role in disease severity assessment is unknown. To inform the use of pulse oximetry in patients with CAP, including the utility of different oxygenation thresholds, patient subgroups, and interaction with existing severity scores. A prospective cohort study of adults with CAP admitted to a UK teaching hospital trust. Oxygen saturations (SpO₂) and the fraction of inspired oxygen were recorded on admission. The value of different SpO₂ thresholds (< 88%, ≤ 90%, ≤ 92%, and < 95%) in predicting 30-day mortality and critical care admission was analysed. 467 patients had SpO₂ measured on room air. Admission SpO₂ ≤ 90% was observed in 28% of patients and had reasonable specificity (76%) for 30-day mortality or critical care admission, but low sensitivity (46%). Specificity was particularly good for adults <50 years of age (90%) or those with asthma (92.3%). SpO₂ ≤ 90% has good specificity but low sensitivity for adverse outcomes in CAP. It complements rather than replaces clinical severity scoring.