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

Abstract

Introduction:

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.

Aims:

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.

Methods:

A prospective cohort study of adults with CAP admitted to a UK teaching hospital trust. Oxygen saturations (S_pO₂) and the fraction of inspired oxygen were recorded on admission. The value of different S_pO₂ thresholds (<88%, ≤90%, ≤92%, and <95%) in predicting 30-day mortality and critical care admission was analysed.

Results:

467 patients had S_pO₂ measured on room air. Admission S_pO₂ ≤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%).

Conclusions:

S_pO₂ ≤90% has good specificity but low sensitivity for adverse outcomes in CAP. It complements rather than replaces clinical severity scoring.

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