title: Transcutaneous carbon-dioxide partial pressure trends during six-minute walk test in patients with very severe COPD.
abstract: Transcutaneous carbon-dioxide partial-pressure (TCPCO2) can be reliably measured and may be of clinical relevance in COPD. Changes in TCPCO2and exercise-induced hypercapnia (EIH) during six-minute walk test (6MWT) need further investigation. We aimed (1) to define patterns of TCPCO2trends during 6MWT and (2) to study determinants of CO2-retention and EIH.
  
  
  
  Sixty-two COPD patients (age: 63±8years, FEV1: 33±10%pred.) were recruited and TCPCO2 was recorded by SenTec digital-monitoring-system during 6MWT.
  
  
  
  Half of patients (50%) exhibited CO2-retention (TCPCO2[Δ]>4mmHg); 26% preserved and 24% reduced TCPCO2. Nineteen (31%) patients presented EIH (TCPCO2>45mmHg). EIH was associated to higher baseline-PCCO2, worse FEV1, lower inspiratory-pressures, underweight/normal BMI, and pre-walk dyspnea. Stronger determinants of CO2-retention were FEV1 and pre-walk dyspnea, whereas baseline-PCCO2and pre-walk dyspnea better predict EIH.
  
  
  
  PCO2response to 6MWT is highly heterogeneous; however, very low FEV1 and elevated baseline-PCCO2together with pre-walk dyspnea increase the risk for CO2-retention and EIH. Overweight-BMI seems to carry a protective effect against EIH in very severe COPD.
authors.affiliation: Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany. Electronic address: VAndrianopoulos@schoen-kliniken.de.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Andrianopoulos
authors.affiliation: Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands. Electronic address: lowievanfleteren@ciro-horn.nl.
authors.forename: Lowie E G W
authors.initials: LE
authors.lastname: Vanfleteren
authors.affiliation: Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany. Electronic address: IJarosch@Schoen-Kliniken.de.
authors.forename: Inga
authors.initials: I
authors.lastname: Jarosch
authors.affiliation: Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department for Prevention, Rehabilitation and Sports Medicine, Klinikum Rechts der Isar, Technische Universität München (TUM), Munich, Germany. Electronic address: RGloeckl@Schoen-Kliniken.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Gloeckl
authors.affiliation: Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department of Pulmonary Rehabilitation, Philipps University Marburg, Marburg, Germany. Electronic address: TSchneeberger@Schoen-Kliniken.de.
authors.forename: Tessa
authors.initials: T
authors.lastname: Schneeberger
authors.affiliation: Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands. Electronic address: ewouters@ciro-horn.nl.
authors.forename: Emiel F M
authors.initials: EF
authors.lastname: Wouters
authors.affiliation: Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; REVAL - Rehabilitation Research Center, BIOMED - Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium. Electronic address: martijnspruit@ciro-horn.nl.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Spruit
authors.affiliation: Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department of Pulmonary Rehabilitation, Philipps University Marburg, Marburg, Germany. Electronic address: KKenn@Schoen-Kliniken.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Kenn
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001785:Blood Gas Monitoring, Transcutaneous; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010313:Partial Pressure; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000503:physiopathology*; D013990:Tidal Volume / Q000502:physiology; D000070857:Walk Test; D016138:Walking / Q000502:physiology*
keywords: 6MWT; CO(2) retention; Chronic obstructive pulmonary disease; Exercise-induced hypercapnia