Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart Failure

Introduction. The relation between minute ventilation (VE) and carbon dioxide production (VCO2) can be characterised by the instantaneous ratio of ventilation to carbon dioxide production, the ventilatory equivalent for CO2 (VEqCO2). We hypothesised that the time taken to achieve the lowest VEqCO2 (...

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Main Authors: Lee Ingle, Rebecca Sloan, Sean Carroll, Kevin Goode, John G. Cleland, Andrew L. Clark
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:Pulmonary Medicine
Online Access:http://dx.doi.org/10.1155/2012/589164
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author Lee Ingle
Rebecca Sloan
Sean Carroll
Kevin Goode
John G. Cleland
Andrew L. Clark
author_facet Lee Ingle
Rebecca Sloan
Sean Carroll
Kevin Goode
John G. Cleland
Andrew L. Clark
author_sort Lee Ingle
collection DOAJ
description Introduction. The relation between minute ventilation (VE) and carbon dioxide production (VCO2) can be characterised by the instantaneous ratio of ventilation to carbon dioxide production, the ventilatory equivalent for CO2 (VEqCO2). We hypothesised that the time taken to achieve the lowest VEqCO2 (time to VEqCO2 nadir) may be a prognostic marker in patients with chronic heart failure (CHF). Methods. Patients and healthy controls underwent a symptom-limited, cardiopulmonary exercise test (CPET) on a treadmill to volitional exhaustion. Results. 423 patients with CHF (mean age 63±12 years; 80% males) and 78 healthy controls (62% males; age 61±11 years) were recruited. Time to VEqCO2 nadir was shorter in patients than controls (327±204 s versus 514±187 s; 𝑃=0.0001). Univariable predictors of all-cause mortality included peak oxygen uptake (𝑋2=53.0), VEqCO2 nadir (𝑋2=47.9), and time to VEqCO2 nadir (𝑋2=24.0). In an adjusted Cox multivariable proportional hazards model, peak oxygen uptake (𝑋2=16.7) and VEqCO2 nadir (𝑋2=17.9) were the most significant independent predictors of all-cause mortality. Conclusion. The time to VEqCO2 nadir was shorter in patients with CHF than in normal subjects and was a predictor of subsequent mortality.
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spelling doaj-art-e99fecaf4fa640acb5e565042a59c6252025-08-20T02:22:15ZengWileyPulmonary Medicine2090-18362090-18442012-01-01201210.1155/2012/589164589164Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart FailureLee Ingle0Rebecca Sloan1Sean Carroll2Kevin Goode3John G. Cleland4Andrew L. Clark5Department of Sport, Health & Exercise Science, University of Hull, Cottingham Road, Kingston-upon-Hull HU6 7RX, UKDepartment of Sport, Health & Exercise Science, University of Hull, Cottingham Road, Kingston-upon-Hull HU6 7RX, UKDepartment of Sport, Health & Exercise Science, University of Hull, Cottingham Road, Kingston-upon-Hull HU6 7RX, UKDepartment of Cardiology, Hull York Medical School, Daisy Building, University of Hull, Castle Hill Hospital, Cottingham, Kingston-upon-Hull HU16 5JQ, UKDepartment of Cardiology, Hull York Medical School, Daisy Building, University of Hull, Castle Hill Hospital, Cottingham, Kingston-upon-Hull HU16 5JQ, UKDepartment of Cardiology, Hull York Medical School, Daisy Building, University of Hull, Castle Hill Hospital, Cottingham, Kingston-upon-Hull HU16 5JQ, UKIntroduction. The relation between minute ventilation (VE) and carbon dioxide production (VCO2) can be characterised by the instantaneous ratio of ventilation to carbon dioxide production, the ventilatory equivalent for CO2 (VEqCO2). We hypothesised that the time taken to achieve the lowest VEqCO2 (time to VEqCO2 nadir) may be a prognostic marker in patients with chronic heart failure (CHF). Methods. Patients and healthy controls underwent a symptom-limited, cardiopulmonary exercise test (CPET) on a treadmill to volitional exhaustion. Results. 423 patients with CHF (mean age 63±12 years; 80% males) and 78 healthy controls (62% males; age 61±11 years) were recruited. Time to VEqCO2 nadir was shorter in patients than controls (327±204 s versus 514±187 s; 𝑃=0.0001). Univariable predictors of all-cause mortality included peak oxygen uptake (𝑋2=53.0), VEqCO2 nadir (𝑋2=47.9), and time to VEqCO2 nadir (𝑋2=24.0). In an adjusted Cox multivariable proportional hazards model, peak oxygen uptake (𝑋2=16.7) and VEqCO2 nadir (𝑋2=17.9) were the most significant independent predictors of all-cause mortality. Conclusion. The time to VEqCO2 nadir was shorter in patients with CHF than in normal subjects and was a predictor of subsequent mortality.http://dx.doi.org/10.1155/2012/589164
spellingShingle Lee Ingle
Rebecca Sloan
Sean Carroll
Kevin Goode
John G. Cleland
Andrew L. Clark
Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart Failure
Pulmonary Medicine
title Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart Failure
title_full Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart Failure
title_fullStr Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart Failure
title_full_unstemmed Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart Failure
title_short Abnormalities of the Ventilatory Equivalent for Carbon Dioxide in Patients with Chronic Heart Failure
title_sort abnormalities of the ventilatory equivalent for carbon dioxide in patients with chronic heart failure
url http://dx.doi.org/10.1155/2012/589164
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