title: Elevated erythrocyte carbonic anhydrase activity is a novel clinical marker in hyperventilation syndrome.
abstract: BACKGROUND
  The aim of this study was to evaluate the erythrocyte carbonic anhydrase (CA) activity in patients with hyperventilation syndrome.
  
  
  METHODS
  A total of 71 patients with hyperventilation syndrome and 60 controls were recruited in this study for measurement of the erythrocyte CA activity. CA activity was analyzed from erythrocyte using CA esterase activity analysis.
  
  
  RESULTS
  The erythrocyte CA activity was significantly elevated in the patients with hyperventilation syndrome compared to controls (31.07+/-1.37 U/g Hb vs. 24.67+/-0.99 U/g Hb, p=0.003). The standardized beta value and significant R(2) value of total CA activity for prediction of hyperventilation was 0.155 (p=0.016) and 0.024, respectively. Moreover, a significant negative correlation was found between total CA activity and partial pressure of carbon dioxide (PaCO(2)) (r=-0.185, p=0.03, n=131). Furthermore, the adjusted odds ratios for patients with hyperventilation were 11.6 (95% CI: 4.8-27.9) and 51.0 (95% CI: 5.8-445.2) for individuals with either PaCO(2)<or=28.1 mm Hg or CA activity >or=29.71 U/g hemoglobin (Hb), and for individuals with both PaCO(2)<or=28.1 mm Hg and CA activity >or=29.71 U/g Hb, respectively, compared to individuals with both PaCO(2)>28.1 mm Hg and CA activity <29.71 U/g Hb.
  
  
  CONCLUSIONS
  Erythrocyte CA activity was significantly elevated in patients with hyperventilation. Detection of erythrocyte CA activity may provide a potential explanatory parameter for the prediction of hyperventilation syndrome.
authors.affiliation: Institute of Medicine, Chung Shan Medical University; Department of Emergency Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Ying-Hock
authors.initials: YH
authors.lastname: Teng
authors.forename: Hsiu-Ting
authors.initials: HT
authors.lastname: Tsai
authors.forename: Yih-Shou
authors.initials: YS
authors.lastname: Hsieh
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Chen
authors.forename: Chiao-Wen
authors.initials: CW
authors.lastname: Lin
authors.forename: Meng-Chih
authors.initials: MC
authors.lastname: Lee
authors.forename: Long-Yau
authors.initials: LY
authors.lastname: Lin
authors.forename: Shun-Fa
authors.initials: SF
authors.lastname: Yang