Biomaterial Database

Determination of cardiac output at rest and during exercise by carbon dioxide rebreathing method in obstructive airway disease. 1985

D A Mahler, and R A Matthay, and P E Snyder, and R K Neff, and J Loke

We evaluated the accuracy of the CO2 rebreathing method (CO2rb) for measuring cardiac output at rest and during steady-state exercise in 15 patients (mean +/- SD age, 59.7 +/- 7.5 yr) with obstructive airway disease. At rest, there was a significant correlation between direct Fick and CO2rb methods using measured arterial PCO2 (r = 0.70; p = 0.002), but not with using end-tidal PCO2 (r = 0.38; p = NS). During exercise, there was greater correlation with CO2rb using arterial PCO2 (r = 0.79; p = 0.001) than using end-tidal PCO2 (r = 0.63; p = 0.007) compared with the direct Fick determination. Correlation between the CO2rb and direct Fick methods was greater with moderate air-flow obstruction (n = 6) than with severe airway disease (n = 9), and the CO2rb method was more accurate during exercise than at rest. The CO2rb method using either end-tidal or arterial PCO2 underestimated the direct Fick measurement in 13 of 15 patients at rest, which may reflect inadequate equilibration between alveolar and oxygenated mixed venous PCO2. However, no consistent error was observed during exercise when higher CO2 production and an increased venoarterial PCO2 difference would diminish potential inaccuracies. We concluded that the CO2rb technique is an acceptable method for measuring cardiac output during exercise in patients with moderate and severe obstructive airway disease as long as arterial PCO2 is directly measured rather than estimated from end-tidal PCO2.

UI	MeSH Term	Description	Entries
D008173	Lung Diseases, Obstructive	Any disorder marked by obstruction of conducting airways of the lung. AIRWAY OBSTRUCTION may be acute, chronic, intermittent, or persistent.	Obstructive Lung Diseases,Obstructive Pulmonary Diseases,Lung Disease, Obstructive,Obstructive Lung Disease,Obstructive Pulmonary Disease,Pulmonary Disease, Obstructive,Pulmonary Diseases, Obstructive
D008297	Male		Males
D008722	Methods	A series of steps taken in order to conduct research.	Techniques,Methodological Studies,Methodological Study,Procedures,Studies, Methodological,Study, Methodological,Method,Procedure,Technique
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D010313	Partial Pressure	The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Partial Pressures,Pressure, Partial,Pressures, Partial
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D012129	Respiratory Function Tests	Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.	Lung Function Tests,Pulmonary Function Tests,Function Test, Pulmonary,Function Tests, Pulmonary,Pulmonary Function Test,Test, Pulmonary Function,Tests, Pulmonary Function,Function Test, Lung,Function Test, Respiratory,Function Tests, Lung,Function Tests, Respiratory,Lung Function Test,Respiratory Function Test,Test, Lung Function,Test, Respiratory Function,Tests, Lung Function,Tests, Respiratory Function
D012146	Rest	Freedom from activity.	Rests
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D002302	Cardiac Output	The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).	Cardiac Outputs,Output, Cardiac,Outputs, Cardiac