[Determination of the hydrogen peroxide level in exhaled breath condensate of patients under mechanical ventilation].
OBJECTIVE
To determine hydrogen peroxide (H(2)O(2)) content in condensate of exhaled breath (EBC) in order to explore its relation with intensify of inflammation of the respiratory tract and prognosis of the patients under mechanical ventilation in respiratory intensive care unit (RICU).


METHODS
Thirty-six patients undergoing mechanical ventilation were studied. EBC was collected on the 1,3,5,7 days after mechanical ventilation. H(2)O(2) in EBC was measured fluorimetrically.


RESULTS
A significantly lowered H(2)O(2) level in the survivors was observed on day 3 [(0.105+/-0.032)micromol/L], day 5 [(0.072+/-0.034)micromol/L] and day 7 [(0.047+/-0.029)micromol/L] compared with day 1 [(0.192+/-0.135) micromol/L] after mechanical ventilation (all P<0.05). A significantly lowered H(2)O(2) level was observed on day 7 compared with day 3 (P<0.05) after mechanical ventilation. There was no difference in the H(2)O(2) level on day 7 compared with day 5 (P>0.05). A significant lower H(2)O(2) level was observed in non-survivors on day 1 [(0.055+/-0.029)micromol/L], and day 3 [(0.088+/-0.040)micromol/L] and day 5 [(0.150+/-0.134)micromol/L] compared with day 7 [(0.234+/-0.152)micromol/L] after mechanical ventilation (all P<0.05). A significantly lower H(2)O(2) level was observed on day 1 compared with day 5 (P<0.05) after mechanical ventilation. There was no difference in the H(2)O(2) level on day 1 compared with day 3 (P>0.05). A significantly lower H(2)O(2) level in non-survivor compared with survivors on day 1 after mechanical ventilation (P<0.05);There was no difference in the H(2)O(2) level between non-survivors and survivors on day 3 after mechanical ventilation (P>0.05).A significantly higher H(2)O(2) level in non-survivors compared with that of survivors on day 5 and day 7 after mechanical ventilation (P<0.05, respectively). The levels of H(2)O(2) in EBC in survivors and non-survivors undergoing mechanical ventilation showed no correlation with acute physiology and chronic health evaluation II (APACHE II) and APACHE III scores (both P>0.05).


CONCLUSIONS
The findings suggest that the level of H(2)O(2) in EBC is correlated with severity of patients under mechanical ventilation, and it may prove to be useful in monitoring of inflammatory reaction in the airway after mechanical ventilation to be used as a guidance of therapy and prognosis in patients under mechanical ventilation.
Yang
Guo-Hui
GH
Department of Respiratory Medicine, Peking University First Hospital, Beijing 100034, China.
Wang
Guang-Fa
GF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001944:Breath Tests; D045853:Exhalation; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis*; D007249:Inflammation; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012121:Respiration, Artificial; D012137:Respiratory System / Q000473:pathology
D006861:Hydrogen Peroxide