title: Transcutaneous PCO2 monitoring in critically ill adults: clinical evaluation of a new sensor.
abstract: OBJECTIVE
  In critically ill patients, arterial blood gas analysis is the gold standard for evaluating systemic oxygenation and carbon dioxide partial pressure. A new miniaturized carbon dioxide tension Pco2-Spo2 single sensor (TOSCA, Linde Medical Sensors AG, Basel, Switzerland) continuously and noninvasively (transcutaneously) monitors both Paco2 and oxygen saturation by pulse oximetry (Spo2). The present study was designed to investigate the usability and the accuracy of this device in critically ill patients.
  
  
  METHODS
  Prospective clinical investigation.
  
  
  METHODS
  A 20-bed, university-affiliated, surgical intensive care unit.
  
  
  METHODS
  Patients admitted after major surgery, multiple trauma, or septic shock equipped with an arterial catheter.
  
  
  METHODS
  The heated (42 degrees C) sensor was fixed at the earlobe using an attachment clip. Transcutaneous Pco2 (TcPco2) measurements were correlated with Paco2 values (measured using a blood gas analyzer). In addition, the differences between Paco2 and TcPco2 values were evaluated using the method of Bland-Altman.
  
  
  RESULTS
  We studied 55 patients, aged 18-80 (mean 57 +/- 15) yrs. A total of 417 paired measurements were compared. Correlation between TcPco2 and Paco2 was r = .86 (p < .01) in the Paco2 range of 24-101 mm Hg. Mean bias (+/-sd) between the two methods of measurement (Bland-Altman analysis) was 1.2 +/- 6.0 mm Hg with TcPco2 slightly overestimating arterial carbon dioxide tension. Nineteen percent of the measured values were outside of the acceptable clinical range of agreement of +/-7.5 mm Hg.
  
  
  CONCLUSIONS
  The present study suggests that Paco2 can be acceptably assessed by measuring TcPco2 using the TOSCA Pco2-Spo2 sensor.
authors.affiliation: Surgical Intensive Care Unit, Department of Anesthesiology, Pharmacology and Surgical Intensive Care, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Karim
authors.initials: K
authors.lastname: Bendjelid
authors.forename: Nicolas
authors.initials: N
authors.lastname: Schütz
authors.forename: Martin
authors.initials: M
authors.lastname: Stotz
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gerard
authors.forename: Peter M
authors.initials: PM
authors.lastname: Suter
authors.forename: Jacques-André
authors.initials: JA
authors.lastname: Romand
mesh_terms: D000328:Adult; D000368:Aged; D001785:Blood Gas Monitoring, Transcutaneous / Q000295:instrumentation*; D013504:Cardiovascular Surgical Procedures; D003422:Critical Care; D016638:Critical Illness; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D009638:Norepinephrine / Q000008:administration & dosage; D011446:Prospective Studies; D015203:Reproducibility of Results; D012737:Sex Factors; D012880:Skin Pigmentation; D014662:Vasoconstrictor Agents / Q000008:administration & dosage; D014781:Viscera / Q000601:surgery
chemical_list: D014662:Vasoconstrictor Agents; D009638:Norepinephrine