title: What is the role of pulse oximetry in the assessment of patients with community-acquired pneumonia in primary care?
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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%).
  
  
  CONCLUSIONS
  SpO₂ ≤ 90% has good specificity but low sensitivity for adverse outcomes in CAP. It complements rather than replaces clinical severity scoring.
authors.affiliation: Department of Respiratory Medicine, David Evans Building, Nottingham City Hospital, Nottingham, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bewick
authors.forename: Sonia
authors.initials: S
authors.lastname: Greenwood
authors.forename: Wei Shen
authors.initials: WS
authors.lastname: Lim
mesh_terms: D000368:Aged; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D011014:Pneumonia / Q000097:blood / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D011320:Primary Health Care; D011379:Prognosis; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D010100:Oxygen