scholarly journals Cardiac Reserve and Pulmonary Gas Exchange Kinetics in Patients With Stroke

Stroke ◽  
2008 ◽  
Vol 39 (11) ◽  
pp. 3102-3106 ◽  
Author(s):  
Corey R. Tomczak ◽  
Anwar Jelani ◽  
Robert G. Haennel ◽  
Mark J. Haykowsky ◽  
Robert Welsh ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Pulmonary Gas Exchange ◽  
Cardiac Reserve ◽  
Exchange Kinetics ◽  
Gas Exchange Kinetics

A New Method Using Pulmonary Gas-Exchange Kinetics To Evaluate Efficacy of β-Blocking Agents in Patients With Dilated Cardiomyopathy

CHEST Journal ◽  
2003 ◽  
Vol 124 (3) ◽  
pp. 954-961 ◽  
Author(s):  
Yasuyo Taniguchi ◽  
Kenji Ueshima ◽  
Ikuo Chiba ◽  
Ikuo Segawa ◽  
Noboru Kobayashi ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Dilated Cardiomyopathy ◽  
Pulmonary Gas Exchange ◽  
New Method ◽  
Blocking Agents ◽  
Exchange Kinetics ◽  
Gas Exchange Kinetics

Effect of interbreath fluctuations on characterizing exercise gas exchange kinetics

1987 ◽  
Vol 62 (5) ◽  
pp. 2003-2012 ◽  
Author(s):  
N. Lamarra ◽  
B. J. Whipp ◽  
S. A. Ward ◽  
K. Wasserman
Keyword(s):  
Gas Exchange ◽  
Least Squares ◽  
Kinetic Parameters ◽  
Nonlinear Least Squares ◽  
Cycle Ergometer ◽  
Gaussian Stochastic Process ◽  
Co2 Output ◽  
Nonsteady State ◽  
Exchange Kinetics ◽  
Gas Exchange Kinetics

Breathing has inherent irregularities that produce breath-to-breath fluctuations (“noise”) in pulmonary gas exchange. These impair the precision of characterizing nonsteady-state gas exchange kinetics during exercise. We quantified the effects of this noise on the confidence of estimating kinetic parameters of the underlying physiological responses and hence of model discrimination. Five subjects each performed eight transitions from 0 to 100 W on a cycle ergometer. Ventilation, CO2 output, and O2 uptake were computed breath by breath. The eight responses were interpolated uniformly, time aligned, and averaged for each subject; and the kinetic parameters of a first-order model (i.e., the time constant and time delay) were then estimated using three methods: linear least squares, nonlinear least squares, and maximum likelihood. The breath-by-breath noise approximated an uncorrelated Gaussian stochastic process, with a standard deviation that was largely independent of metabolic rate. An expression has therefore been derived for the number of square-wave repetitions required for a specified parameter confidence using methods b and c; method a being less appropriate for parameter estimation of noisy gas exchange kinetics.

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