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

Prim Care Respir J. 2010 Dec;19(4):378-82. doi: 10.4104/pcrj.2010.00049.


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 (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.

Results: 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%).

Conclusion: SpO₂ ≤ 90% has good specificity but low sensitivity for adverse outcomes in CAP. It complements rather than replaces clinical severity scoring.

MeSH terms

  • Aged
  • Female
  • Hospital Mortality
  • Humans
  • Male
  • Middle Aged
  • Oximetry*
  • Oxygen / blood
  • Pneumonia / blood
  • Pneumonia / diagnosis*
  • Pneumonia / mortality
  • Pneumonia / therapy
  • Primary Health Care
  • Prognosis
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Treatment Outcome


  • Oxygen