title: Comparison of arterial and venous pH, bicarbonate, PCO2 and PO2 in initial emergency department assessment.
abstract: OBJECTIVE
  To determine the agreement between arterial and venous samples in a pathologically diverse patient population presenting at an emergency department (ED) with a view to obviating the need for arterial blood gas (ABG) analysis in initial ED evaluation.
  
  
  METHODS
  Prospective study of 95 patients (69 males, 26 females, mean (SD) age 52 (1.6) years) with diverse medical conditions, presenting at a tertiary health centre ED and deemed by the treating physician to require an ABG analysis. Arterial and venous samples for gas analysis were taken as close in time to each other as possible. The data thus obtained were analysed for agreement between pH, Pco(2), Po(2) and bicarbonate using the Bland-Altman method.
  
  
  RESULTS
  The arterial and venous values of pH, bicarbonate and Pco(2) show acceptably narrow 95% limits of agreement using the Bland-Altman method (0.13 to -0.1, 4.3 to -5.8 and 6.8 to -7.6, respectively). Agreement in Po(2) measurements was poor (95% limits of agreement 145.3 to -32.9).
  
  
  CONCLUSIONS
  Venous blood gas analysis for pH, bicarbonate and Pco(2) may be a reliable substitute for ABG analysis in the initial evaluation of an adult patient population presenting to the ED.
authors.affiliation: Department of Internal Medicine and Dept of Emergency Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: G
authors.initials: G
authors.lastname: Malatesha
authors.forename: Nishith K
authors.initials: NK
authors.lastname: Singh
authors.forename: Ankur
authors.initials: A
authors.lastname: Bharija
authors.forename: Bhavya
authors.initials: B
authors.lastname: Rehani
authors.forename: Ashish
authors.initials: A
authors.lastname: Goel
mesh_terms: D001158:Arteries; D001639:Bicarbonates / Q000097:blood*; D001784:Blood Gas Analysis / Q000379:methods*; D004635:Emergency Medicine / Q000379:methods*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies; D014680:Veins
chemical_list: D001639:Bicarbonates; D010100:Oxygen