title: [Precision and accuracy of "a pocket" pulse oximeter in Mexico City].
abstract: BACKGROUND
  Pulse oximeters are frequently used in the clinical practice and we must known their precision and accuracy. The objective was to evaluate the precision and accuracy of a "pocket" pulse oximeter at an altitude of 2,240 m above sea level.
  
  
  METHODS
  We tested miniature pulse oximeters (Onyx 9,500, Nonin Finger Pulse Oximeter) in 96 patients sent to the pulmonary laboratory for an arterial blood sample. Patients were tested with 5 pulse oximeters placed in each of the fingers of the hand oposite to that used for the arterial puncture. The gold standard was the oxygen saturation of the arterial blood sample.
  
  
  RESULTS
  Blood samples had SaO2 of 87.2 +/- 11.0 (between 42.2 and 97.9%). Pulse oximeters had a mean error of 0.28 +/- 3.1%. SaO2 = (1.204 x SpO2) - 17.45966 (r = 0.92, p < 0.0001). Intraclass correlation coefficient between each of five pulse oximeters against the arterial blood standard ranged between 0.87 and 0.99. HbCO (2.4 +/- 0.6) did not affect the accuracy.
  
  
  CONCLUSIONS
  The miniature oximeter Nonin is precise and accurate at 2,240 m of altitude. The observed levels of HbCO did not affect the performance of the equipment. The oximeter good performance, small size and low cost enhances its clinical usefulness.
authors.affiliation: Clínica de Suefio, Instituto Nacional de Enfermedades Respiratorias, Tlalpan, DF México.
authors.forename: Luis
authors.initials: L
authors.lastname: Torre-Bouscoulet
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Chávez-Plascencia
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Vázquez-García
authors.forename: Rogelio
authors.initials: R
authors.lastname: Pérez-Padilla
mesh_terms: D000328:Adult; D000368:Aged; D000531:Altitude; D002263:Carboxyhemoglobin / Q000032:analysis; D004781:Environmental Exposure; D005260:Female; D005385:Fingers; D006452:Hemoglobinometry / Q000379:methods; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D008297:Male; D008706:Methemoglobin / Q000032:analysis; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D010092:Oximetry / Q000191:economics / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood*; D010108:Oxyhemoglobins / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012906:Smoke; D012907:Smoking / Q000097:blood / Q000453:epidemiology; D013053:Spectrophotometry; D014028:Tobacco Smoke Pollution; D014505:Urban Population
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; D012906:Smoke; D014028:Tobacco Smoke Pollution; D008706:Methemoglobin; D002263:Carboxyhemoglobin; D010100:Oxygen