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Updated: Oct 2, 2026

Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
[The tissue oxygenation status and the effects of mechanical ventilation on oxygen dynamics in COPD patients with
1Dept. of Pulmonary Med. Beijing Red Cross Chaoyang Hospital Affiliate of Capital University of Medical Sciences, Beijing 100020.
Objective:
To assess the tissue oxygenation status and the effects of mechanical ventilation (MV) on oxygen dynamics in COPD patient with hypercapnia.
Methods:
Gastric intramucosal pH (pHi) measured by gastric tonometer was examined in 19 patients before and after MV.
Results:
pHi calculated before MV was 7.18 +/- 0.06; After receiving MV, pHi increased gradually until above 7.32 in 4 days; during weaning, there were no significant changes in pHi before and after discontinuation. The correlation analysis showed that there was no correlation between pHi and pHa (r = 0.352, P > 0.05), PgCO(2) and PaCO(2) (r = 0.421, P > 0.05), suggesting that pHi measurement would not be affected by hypercapnia.
Conclusions:
Our study showed that tissue oxygenation insufficiency existed in COPD exacerbation stage. Gastric pHi may be used as the parameter to estimate tissue oxygenation status and a predictor of weaning from mechanical ventilation.
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