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Updated: Jun 3, 2026
Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
PaCO2 six months after the initiation of long-term noninvasive ventilation in patients with COPD
Tomomasa Tsuboi1, Toru Oga, Kazuko Machida
1Department of Respiratory Care and Sleep Control Medicine, Kyoto University Graduate School of Medicine, Japan. tsuboit@skyoto.hosp.go.jp
Background And Objective:
The appropriate target level for PaCO(2) after the introduction of long-term noninvasive positive pressure ventilation (NPPV) in patients with COPD remains uncertain, and therefore must be tested.
Methods:
Data on 54 patients with COPD receiving long-term domiciliary NPPV were examined retrospectively. PaCO(2) a few months after NPPV and potential confounders were analyzed with discontinuation of long-term NPPV as the primary outcome. The differences in annual hospitalization rates due to respiratory deterioration between those from 1 year before to 2 years after initiation of NPPV were compared according to the PaCO(2) measured at 6 months after NPPV (6-mo PaCO(2)).
Results:
6-mo PaCO(2) seemed to be most related to continuation of NPPV (p=0.019). Patients with 6-mo PaCO(2) of less than 60 mmHg had maintained a significantly lower PaCO(2) value 6 to 24 months after NPPV (p=0.04) and had a significantly higher continuation rate of NPPV (p=0.03) than those with a 6-mo PaCO(2) of 60 mmHg or more. Annual hospitalization rates due to respiratory deterioration were not associated with the 6-mo PaCO(2) level, but fatal hospitalization rates during the first year of NPPV were significantly correlated with relatively high 6-mo PaCO(2) (p=0.008).
Conclusion:
A relatively low 6-mo PaCO(2) value was predictive of long-term use of NPPV. The target values of 6-mo PaCO(2) may, therefore, be less than 60 mmHg in COPD patients with extremely severe hypercapnia, although more prospective studies are needed.
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