Diagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.

STUDY OBJECTIVES: Parapneumonic effusions are common, and measurement of pleural pH is one of the most useful measurements in assessing the need for tube drainage. Use of pleural pH assumes that a single measurement conveys a representative picture of pH throughout the effusion. Often effusions are...

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Main Authors: Maskell, N, Gleeson, F, Darby, M, Davies, R
Format: Journal article
Language:English
Published: 2004
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author Maskell, N
Gleeson, F
Darby, M
Davies, R
author_facet Maskell, N
Gleeson, F
Darby, M
Davies, R
author_sort Maskell, N
collection OXFORD
description STUDY OBJECTIVES: Parapneumonic effusions are common, and measurement of pleural pH is one of the most useful measurements in assessing the need for tube drainage. Use of pleural pH assumes that a single measurement conveys a representative picture of pH throughout the effusion. Often effusions are multiloculated, and varying concentrations of nondiffusible acids such as lactic acid, if present in different concentrations, could mean clinically significant variations in pH between locules. If these differences were large, a single pH measurement could misrepresent the "stage" that the parapneumonic effusion had reached. We therefore set out to test the hypothesis that pH varies significantly between locules in complicated parapneumonic effusions. DESIGN: The study was performed in seven consecutive patients presenting to our institution with complicated parapneumonic effusions. INTERVENTIONS: In each case, pleural pH was measured in several separate pleural fluid locules, using ultrasound-guided pleural fluid sampling. RESULTS: Significant variations were found in pleural fluid visual appearance, pH, and lactate dehydrogenase between locules in four of seven patients. Three of seven patients had variations, resulting in pH levels both above and below 7.2, which is the threshold used in our institution to indicate the need for tube drainage. CONCLUSIONS: This is the first reported series of variation in pleural pH between different locules in complicated parapneumonic effusions. These variations are clinically important and cast light on the mechanisms responsible for the acidosis seen in infected effusions. Physicians should be aware of this when making drainage decisions in these patients using the clinical picture and a single pH result alone.
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spelling oxford-uuid:70611214-35cf-4e4a-8dab-9727155496762022-03-26T19:36:44ZDiagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:70611214-35cf-4e4a-8dab-972715549676EnglishSymplectic Elements at Oxford2004Maskell, NGleeson, FDarby, MDavies, R STUDY OBJECTIVES: Parapneumonic effusions are common, and measurement of pleural pH is one of the most useful measurements in assessing the need for tube drainage. Use of pleural pH assumes that a single measurement conveys a representative picture of pH throughout the effusion. Often effusions are multiloculated, and varying concentrations of nondiffusible acids such as lactic acid, if present in different concentrations, could mean clinically significant variations in pH between locules. If these differences were large, a single pH measurement could misrepresent the "stage" that the parapneumonic effusion had reached. We therefore set out to test the hypothesis that pH varies significantly between locules in complicated parapneumonic effusions. DESIGN: The study was performed in seven consecutive patients presenting to our institution with complicated parapneumonic effusions. INTERVENTIONS: In each case, pleural pH was measured in several separate pleural fluid locules, using ultrasound-guided pleural fluid sampling. RESULTS: Significant variations were found in pleural fluid visual appearance, pH, and lactate dehydrogenase between locules in four of seven patients. Three of seven patients had variations, resulting in pH levels both above and below 7.2, which is the threshold used in our institution to indicate the need for tube drainage. CONCLUSIONS: This is the first reported series of variation in pleural pH between different locules in complicated parapneumonic effusions. These variations are clinically important and cast light on the mechanisms responsible for the acidosis seen in infected effusions. Physicians should be aware of this when making drainage decisions in these patients using the clinical picture and a single pH result alone.
spellingShingle Maskell, N
Gleeson, F
Darby, M
Davies, R
Diagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.
title Diagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.
title_full Diagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.
title_fullStr Diagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.
title_full_unstemmed Diagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.
title_short Diagnostically significant variations in pleural fluid pH in loculated parapneumonic effusions.
title_sort diagnostically significant variations in pleural fluid ph in loculated parapneumonic effusions
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AT gleesonf diagnosticallysignificantvariationsinpleuralfluidphinloculatedparapneumoniceffusions
AT darbym diagnosticallysignificantvariationsinpleuralfluidphinloculatedparapneumoniceffusions
AT daviesr diagnosticallysignificantvariationsinpleuralfluidphinloculatedparapneumoniceffusions