title: The revised digital transcutaneous PCO2/SpO2 ear sensor is a reliable noninvasive monitoring tool in patients after cardiac surgery.
abstract: OBJECTIVE
  The aim of this study was to validate the revised SenTec V-Sign 2 sensor (SenTec AG, Therwil, Switzerland) for combined noninvasive continuous assessment of pulse rate, pulse oximetry (SpO(2)), and transcutaneous carbon dioxide tension (PtcCO(2)) in adults after cardiac surgery.
  
  
  METHODS
  A prospective clinical study.
  
  
  METHODS
  A single-center university hospital.
  
  
  METHODS
  Twenty adult patients aged 36 to 84 years after cardiac surgery.
  
  
  METHODS
  SpO(2) and PtcCO(2) values of three V-Sign 2 sensors (SenTec AG) attached at the earlobe, forehead, and cheek and SpO(2) values of the Nellcor Durasensor (Model DS-100A; Nellcor Puritan Bennett Inc, Pleasanton, CA) were compared with simultaneous measurements of blood gases and end-expiratory carbon dioxide.
  
  
  RESULTS
  Measurements were performed during periods of hyper-, normo-, and hypocapnia and then at 30-minute intervals up to 5 hours. Bland-Altman analysis and simple regression analysis were used.
  
  
  RESULTS
  The detection failures for PtcCO(2) were 0.3% to 1.3%, for SpO(2) 10% to 25%, and for pulse rate 5% to 10%. The V-Sign 2 earlobe sensor provided the best results. The mean bias and limits of agreement for PtcCO(2ear) and PaCO(2) were 1.1 and -3.4/+5.5 mmHg. The drift of PtcCO(2) was negligible at all locations. The mean bias and limits of agreement of V-Sign SpO(2ear) and SaO(2), as well as V-Sign pulse rate and the electrocardiogram, were -1.7% and -6.8/+3.9% and 1.2 beats/min and -3.3/+5.8 beats/min. End-expiratory carbon dioxide showed a weak correlation with PaCO(2) (r(2) = 0.47).
  
  
  CONCLUSIONS
  Transcutaneous capnometry using the revised V-Sign 2 sensor at the earlobe is a reliable monitoring tool during the recovery period of patients after cardiac surgery. This approach has the potential to reduce the number of arterial blood gas samples.
authors.affiliation: Institute of Anaesthesiology, University Hospital of Zurich, Zurich, Switzerland.
authors.forename: Regine
authors.initials: R
authors.lastname: Roediger
authors.forename: Beatrice
authors.initials: B
authors.lastname: Beck-Schimmer
authors.forename: Oliver M
authors.initials: OM
authors.lastname: Theusinger
authors.forename: Denise
authors.initials: D
authors.lastname: Rusch
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Seifert
authors.forename: Donat R
authors.initials: DR
authors.lastname: Spahn
authors.forename: Edith R
authors.initials: ER
authors.lastname: Schmid
authors.forename: Werner
authors.initials: W
authors.lastname: Baulig
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis / Q000379:methods / Q000592:standards; D001785:Blood Gas Monitoring, Transcutaneous / Q000379:methods / Q000592:standards; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000379:methods; D004423:Ear / Q000098:blood supply* / Q000502:physiology*; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000097:blood / Q000175:diagnosis; D016857:Hypocapnia / Q000097:blood / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods / Q000592:standards; D010092:Oximetry / Q000379:methods* / Q000592:standards; D011446:Prospective Studies