| Using Statistical Techniques to Predict Dynamic Arterial PCO₂ in COPD Patients During Maximum Exercise. | |
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MedLine Citation:
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PMID: 22272573 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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BACKGROUND: PaCO₂ as measured during exercise in COPD patients is poorly predicted (PaCO₂pred) from lung function testing and some noninvasive measurements such as end-tidal PCO₂s (PETCO₂). OBJECTIVE: We performed a number of statistical techniques on PETCO₂ and its interaction with other physiologic variables during exercise testing in order to improve our ability to predict PaCO₂. The estimated PaCO₂ as determined from these techniques may therefore be used (1) to contrast the PETCO₂ readings that are measured during an incremental exercise test on a breath-by-breath basis (i.e., Pa-ETCO₂); and (2) to identify exercise-induced hypercapnia. METHODS: 47 men with COPD underwent both pulmonary function testing and incremental exercise testing until limited by symptoms. Arterial blood gases and exercise physiological measurements were performed during maximal exercise testing. The prediction equations for PaCO₂ were generated using regression techniques with the leave-one-out cross-validation technique. RESULTS: 41 patients were included in the final analysis after six patients were excluded due to inadequate data collection. The best prediction equation we found was: PaCO₂pred = 23.71+PETCO₂ × (0.9-0.00531 × DLCO-0.03704 × VT)-2.61 × SVC-0.039 × MEP where DLCO is diffusing capacity for carbon monoxide in mL/min/mm Hg; VT is tidal volume in L; SVC is slow vital capacity in L; and MEP is maximum expiratory pressure in cm H₂O. The difference between the measured and predicted PaCO₂ at each time point was not statistically significant (all P > 0.05). The standard errors of the estimated PaCO₂ at each time point were 0.91-1.12 mm Hg. CONCLUSIONS: A validated mixed-model regression derived equation yields a predicted PaCO₂ trend during exercise that can be helpful when interpreting exercise testing to determine Pa-ETCO₂ and exercise-induced hypercapnia. |
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Authors:
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Ming-Lung Chuang; I-Feng Lin; Janine Vintch; En-Hao Tien |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-23 |
Journal Detail:
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Title: Respiratory care Volume: - ISSN: 0020-1324 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-25 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7510357 Medline TA: Respir Care Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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