title: Accuracy of symptoms and signs in predicting hypoxaemia among young children with acute respiratory infection: a meta-analysis.
abstract: OBJECTIVE
  To assess the accuracy of clinical symptoms and signs in predicting hypoxaemia among young children with acute respiratory infection (ARI).
  
  
  METHODS
  We conducted a systematic review and meta-analysis of prospective diagnostic studies that evaluated the accuracy of individual or combined clinical symptoms and signs in predicting hypoxaemia among children aged <5 years with ARI. MEDLINE® was searched for articles published between 1950 and March 2010. Measurement of arterial haemoglobin oxygen saturation by pulse oximetry was used as reference standard. The hierarchical summary receiver operating characteristic model for meta-analyses was applied.
  
  
  RESULTS
  Eleven diagnostic studies with 5787 patients were included in the review. There was substantial variation in sensitivity and specificity between different symptoms and signs as well as across studies. Cyanosis, inability to feed, head nodding, respiratory rate > 70/min and unresponsiveness/impaired rousability had high specificity but low sensitivity. In contrast, reported rapid breathing and crepitations in lung auscultation had relatively high sensitivity but low specificity. Five models of a combination of symptoms and signs presented moderate sensitivity (range 0.60-0.84) and specificity (range 0.63-0.82).
  
  
  CONCLUSIONS
  Neither single nor combined symptoms and signs have satisfactory performance in predicting hypoxaemia among young children with ARI. Improved access to pulse oximetry is needed in developing countries.
authors.affiliation: Maternal and Child Health Unit, Faculty of Medicine, Federal University of Rio Grande, Rio Grande, Brazil. zhanglinjie63@yahoo.com.br
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: R
authors.initials: R
authors.lastname: Mendoza-Sassi
authors.forename: J C H
authors.initials: JC
authors.lastname: Santos
authors.forename: J
authors.initials: J
authors.lastname: Lau
mesh_terms: D000208:Acute Disease; D002675:Child, Preschool; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D007223:Infant; D007231:Infant, Newborn; D015233:Models, Statistical; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D012372:ROC Curve; D012141:Respiratory Tract Infections / Q000150:complications* / Q000503:physiopathology; D012680:Sensitivity and Specificity
chemical_list: D006454:Hemoglobins; D010100:Oxygen