HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Budweiser, S. Articles by Pfeifer, M. Search for Related Content PubMed Articles by Budweiser, S. Articles by Pfeifer, M.

Base excess, a marker of chronic hypercapnic respiratory failure and predictor of survival in COPD

^* Center for Pneumology, Donaustauf Hospital, Donaustauf, Germany ^# Institute and Outpatient Clinic for Occupational and Environmental Medicine, Ludwig-Maximilians-University, Munich, Germany ^¶ Dept of Internal Medicine II, University of Regensburg, Regensburg, Germany

CORRESPONDENCE: Stephan Budweiser, Center for Pneumology, Donaustauf Hospital, Donaustauf, Germany

We studied the role of base excess (BE) as marker of chronic hypercapnia and survival in patients with chronic obstructive pulmonary disease (COPD) and chronic hypercapnic respiratory failure (CHRF). Moreover, it was investigated whether the effects of non-invasive positive pressure ventilation (NPPV) on CHRF were reflected in BE and survival.

In 240 (160 without exacerbation) patients with COPD (mean±SD FEV1 30.7±9.7 %pred; PaCO₂ 56.9±9.9 mmHg) body-mass index (BMI), lung function, respiratory muscle function, blood gases and 6-minute walking distance (6-MWD) were assessed prior to initiation of NPPV. In addition, the changes of risk factors 6.3±2.9 months after initiation of NPPV were evaluated.

Overall mortality during the follow-up time (26.0±24.5 months) was 34.6%. Deaths resulted predominantly from respiratory causes (65.1%); among those, respiratory failure was most frequent (85.2%). Univariate analysis revealed BMI, FEV1, maximal inspiratory pressure (PI_max), inspiratory load (P_0.1), haemoglobin, 6-MWD, hyperinflation (IC/TLC, RV/TLC), blood gases and BE to be associated (p<0.05 each) with prognosis. In multivariate analyses, however, only BMI, RV/TLC and BE turned out to be independent cross-sectional predictors (p<0.05). Kaplan-Meier analyses showed that BE had predictive value particularly in patients with BMI25 kg·m^–2, RV/TLC70 % and PaCO₂57 mmHg. Furthermore, changes of BMI, RV/TLC and BE (p<0.01) were associated with improved prognosis in severe hypercapnic COPD.

In patients with COPD and CHRF, BE was a prognostic marker for mortality, that was independent from other factors, particularly PaCO₂. In addition, reversal of CHRF was reflected in BE and appeared to have an impact on prognosis.