title: A nasal catheter for the measurement of end-tidal carbon dioxide in spontaneously breathing patients: a preliminary evaluation.
abstract: BACKGROUND
  Several devices have been proposed to monitor end-tidal carbon dioxide tension (Petco(2)) in spontaneously breathing patients; however, many have been reported to be inaccurate. We designed this study to investigate the accuracy of a balloon-tipped nasal catheter in measuring Petco(2) in nontracheally intubated, spontaneously breathing patients.
  
  
  METHODS
  The catheter was assembled using a 14-F rubber Foley catheter, a tracheal tube pilot balloon, and the plastic sheath from an 18-gauge needle. The catheter was connected to the sampling tube of a gas analyzer. Petco(2) and Paco(2) were determined simultaneously in 20 otherwise healthy postsurgical patients while receiving oxygen.
  
  
  RESULTS
  The mean Petco(2) - Paco(2) difference was -4.4 +/- 1.6 (SD) mm Hg with a correlation coefficient r = +0.87 (P < 0.001).
  
  
  CONCLUSIONS
  Our results suggest that a balloon-tipped nasal catheter can provide a simple, easy, and reliable method for Petco(2) measurement in nontracheally intubated, spontaneously breathing patients.
authors.affiliation: Anesthesiology Department, Asyut University Hospital, Asyut, Egypt. msraheem@doctors.net.uk
authors.forename: Mohamed Samy Abdel
authors.initials: MS
authors.lastname: Raheem
authors.forename: Olaa M
authors.initials: OM
authors.lastname: Wahba
mesh_terms: D000328:Adult; D000769:Anesthesia, Inhalation; D001784:Blood Gas Analysis; D019296:Capnography / Q000295:instrumentation* / Q000379:methods*; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism*; D002404:Catheterization / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009296:Nasal Cavity; D010102:Oxygen Inhalation Therapy; D015203:Reproducibility of Results; D015656:Respiratory Mechanics / Q000502:physiology*; D012907:Smoking / Q000503:physiopathology
chemical_list: D002245:Carbon Dioxide