Background: Exacerbation of chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality, but the effect of metabolic compensation of respiratory acidosis (RA) on mortality is not fully understood. Objective: To investigate the relationship between metabolic compensation and mortality in COPD patients with RA. Methods: We prospectively investigated all COPD patients with RA admitted to the respiratory intensive care unit between February 2001 and March 2007. Two hundred and thirteen patients (159 male, 54 female; mean age 65 ± 10.8 years) were divided into three groups (71 patients each) according to base excess (BE) levels: (1) low BE, (2) medium BE, and (3) high BE. H+ concentration was calculated according to their standard formula and BE was calculated according to the Van Slyke equation. Results: The overall mortality rate was 24.9%. The group mortality rates were 32, 17 and 25% in the low, medium and high BE groups, respectively (p = 0.001). When patients were divided into three groups according to the HCO3– levels, the group mortality rate was 59.1% in the low HCO3– group and 19.8% in the high HCO3– group. Based on univariate analysis, six factors affecting mortality were identified. However, multivariate analysis showed that the levels of serum HCO3– (p = 0.013; OR: 0.552; CI: 0.345–0.882) and creatinine (p = 0.019; OR: 2.114; CI: 1.132–3.949) had an independent effect. Conclusion: In patients with COPD exacerbation and hypercapnia, the development of sufficient metabolic compensation and adequate renal function significantly decreases mortality.

Keywords:
Chronic obstructive pulmonary disease, Respiratory acidosis, Metabolic alkalosis, Hypercapnia
1.
Jeffrey A, Warren P, Flenley D: Acute hypercapnic respiratory failure in patients with chronic obstructive lung disease: risk factors and use of guidelines for management. Thorax 1992;47:34–40.
2.
Afessa B, Morales IJ, Scanlon PD, Peters SG: Prognostic factors, clinical course, and hospital outcome of patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure. Crit Care Med 2002;30:1610–1615.
3.
Moran JL, Green JV, Homan SD, Leeson RJ, Leppard PI: Acute exacerbations of chronic obstructive pulmonary disease and mechanical ventilation: a reevaluation. Crit Care Med 1998;26:71–78.
4.
Nevins ML, Epstein SK: Predictors of outcome for patients with COPD requiring invasive mechanical ventilation. Chest 2001;119:1840–1849.
5.
Groenewegen KH, Schols AM, Wouters EF: Mortality and mortality-related factors after hospitalization for acute exacerbation of COPD. Chest 2003;124:459–467.
6.
Ucgun I, Metintas M, Moral H, Alatas F, Yildirim H, Erginel S: Predictors of hospital outcome and intubation in COPD patients admitted to the respiratory ICU for acute hypercapnic respiratory failure. Respir Med 2005;100:66–74.
7.
Hodgkin JE, Soeprono FF, Chan DM: Incidence of metabolic alkalemia in hospitalized patients. Crit Care Med 1980;8:725–728.
8.
Webster NR, Kulkarni V: Metabolic alkalosis in the critically ill. Crit Rev Clin Lab Sci 1999;36:497–510.
9.
Standards for the diagnosis and care of patients with chronic obstructive pulmonary disease. American Thoracic Society statement. Am J Respir Crit Care Med 1995;152:S77–S120.
10.
NHLBI/WHO Workshop Report: Global Initiative for Chronic Obstructive Pulmonary Diseases, 2001, pp 1–104.
11.
Knaus WA, Draper EA, Wagner DP, Zimmerman JE: APACHE II: a severity of disease classification system. Crit Care Med 1985;13:818–829.
12.
Lang W, Zander R: The accuracy of calculated base excess in blood. Clin Chem Lab Med 2002;40:404–410.
13.
Akgun M, Meral M, Onbas O, et al: Comparison of clinical characteristics and outcomes of patients with COPD exacerbation with or without venous thromboembolism. Respiration 2006;73:428–433.
14.
Wilson RF, Gibson D, Percinel AK, et al: Severe alkalosis in critically ill surgical patients. Arch Surg 1972;105:197.
15.
Anderson LE, Henrich WL: Alkalemia-associated morbidity and mortality in medical and surgical patients. South Med J 1987;80:729–733.
16.
Weiss SM, Hudson LD: Outcome from respiratory failure. Crit Care Clin 1994;10:197–215.
17.
Connors AF Jr, Dawson NV, Thomas C, et al: Outcomes following acute exacerbation of severe chronic obstructive lung disease: the SUPPORT investigators (Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments). Am J Respir Crit Care Med 1996;154:959–967.
18.
Fuso L, Incalzi RA, Pistelli R, et al: Predicting mortality of patients hospitalized for acutely exacerbated chronic obstructive pulmonary disease. Am J Med 1995;98:272–277.
19.
Anthonisen NR, Wright EC, Hodgkin JE: Prognosis in chronic obstructive pulmonary disease. Am Rev Respir Dis 1986;133:14–20.
20.
Gray-Donald K, Gibbons L, Shapiro SH, et al: Nutritional status and mortality in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1996;153:961–966.
21.
Landbo C, Prescott E, Lange P, et al: Prognostic value of nutritional status in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1999;160:1856–1861.
22.
Schols A, Slangen J, Volovics L, et al: Weight loss is a reversible factor in the prognosis of chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1998;157:1791–1797.
23.
Incalzi RA, Fuso L, DeRosa M, et al: Co-morbidity contributes to predict mortality of patients with chronic obstructive pulmonary disease. Eur Respir J 1997;10:2794–2800.
24.
Groenewegen KH, Schols AM, Wouters EFM: Mortality and mortality-related factors after hospitalization for acute exacerbation of COPD. Chest 2003;124:459–467.
25.
Gursel G: Determinants of the length of mechanical ventilation in patients with COPD in the intensive care unit. Respiration 2005;72:61–67.
26.
Hoo GW, Hakimian N, Santiago SM: Hypercapnic respiratory failure in COPD patients: response to therapy. Chest 2000;117:169–177.
27.
Kettel LJ, Diener CF, Morse JO, et al: Treatment of acute respiratory acidosis in chronic obstructive lung disease. JAMA 1971;217:1503–1508.
28.
Warren PM, Flenley DC, Millar JS, et al: Respiratory failure revisited: acute exacerbations of chronic bronchitis between 1961–68 and 1970–76. Lancet 1980;1:467–470.
© 2008 S. Karger AG, Basel
2008
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.