Cardiovascular, respiratory, and metabolic adjustments to exercise in dogs

1977 ◽  
Vol 42 (3) ◽  
pp. 403-407 ◽  
Author(s):  
J. A. Wagner ◽  
S. M. Horvath ◽  
T. E. Dahms
Keyword(s):  
Cardiac Output ◽  
Central Body ◽  
Metabolic Parameters ◽  
Body Temperatures ◽  
Vo2 Max ◽  
Co2 Gas ◽  
Heart Rates ◽  
Pentobarbital Sodium ◽  
Anesthetized Dogs ◽  
Mixed Venous

Cardiovascular and metabolic parameters were studied in dogs anesthetized with pentobarbital sodium, and while awake resting or exercising for 30 min at either 6.4 km/h, 10% grade (32% VO2 max) or 8.0 km/h, 16% grade (50% VO2 max). The anesthetized dogs had lower cardiac outputs, stroke volumes, arterial-mixed venous oxygen differences, oxygen uptakes, rectal temperatures, and higher diastolic and mean arterial pressures than awake resting dogs. Heart rates and arterial systolic pressures were similar in the two conditions. The increased oxygen uptakes during exercise were associated with approximately equal percentage increments in cardiac outputs and oxygen extractions. Cardiac output increases during exercise were largely due to increases in heart rates. Arterial CO2 tension and CO2 contents as well as venous O2 and CO2 gas tensions and contents declined, and pH and rectal temperatures increased during exercise. The dogs became alkalotic during exercise. Elevated central body temperatures appeared to be the major factor controlling respiration.

Appearance of excess lactate in anesthetized dogs during anemic and hypoxic hypoxia

1965 ◽  
Vol 209 (3) ◽  
pp. 604-610 ◽  
Author(s):  
Stephen M. Cain
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Oxygen Transport ◽  
Liver Dysfunction ◽  
Hypoxic Hypoxia ◽  
Blood Gas ◽  
Total Oxygen ◽  
Anesthetized Dogs ◽  
Lactate And Pyruvate ◽  
Mixed Venous

Ten anesthetized, splenectomized dogs were made progressively anemic by replacement of blood with warmed dextran to approximate hematocrits of 30, 20, 15, and 10%. A second group of 10 dogs was made progressively hypoxic by having them inspire 11.4, 9.5, 8.0, and 5.9% O2 in N2. Blood gas contents, pH, and gas tensions were measured in arterial and mixed venous bloods. Cardiac output was calculated from the arteriovenous O2 difference and the O2 uptake. Excess lactate was calculated from measured levels of lactate and pyruvate in blood water. Excess lactate appeared at higher mixed venous Po2 in anemic animals than in hypoxic, 40 mm Hg versus 20 mm Hg. When related to total oxygen transport, however, excess lactate appeared at about the same point (12 ml/kg per min) in both groups. Because liver has been shown to reduce its oxygen uptake with any lowering of perfusate oxygen content, it was suggested that the excess lactate measured during both anemic and hypoxic hypoxia in anesthetized dogs is largely the result of liver dysfunction with respect to lactate.

scholarly journals Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury

2007 ◽  
Vol 102 (1) ◽  
pp. 331-339 ◽  
Author(s):  
Rebecca S. Syring ◽  
Cynthia M. Otto ◽  
Rebecca E. Spivack ◽  
Klaus Markstaller ◽  
James E. Baumgardner
Keyword(s):  
Cardiac Output ◽  
Lung Injury ◽  
Respiratory Rate ◽  
Pressure Control ◽  
Plateau Pressure ◽  
Control Mode ◽  
Intrinsic Peep ◽  
Mixed Venous Saturation ◽  
Mixed Venous ◽  
Saline Lavage

Cyclical recruitment of atelectasis with each breath is thought to contribute to ventilator-associated lung injury. Extrinsic positive end-expiratory pressure (PEEPe) can maintain alveolar recruitment at end exhalation, but PEEPe depresses cardiac output and increases overdistension. Short exhalation times can also maintain end-expiratory recruitment, but if the mechanism of this recruitment is generation of intrinsic PEEP (PEEPi), there would be little advantage compared with PEEPe. In seven New Zealand White rabbits, we compared recruitment from increased respiratory rate (RR) to recruitment from increased PEEPe after saline lavage. Rabbits were ventilated in pressure control mode with a fraction of inspired O2 (FiO2) of 1.0, inspiratory-to-expiratory ratio of 2:1, and plateau pressure of 28 cmH2O, and either 1) high RR ( 24 ) and low PEEPe (3.5) or 2) low RR ( 7 ) and high PEEPe ( 14 ). We assessed cyclical lung recruitment with a fast arterial Po2 probe, and we assessed average recruitment with blood gas data. We measured PEEPi, cardiac output, and mixed venous saturation at each ventilator setting. Recruitment achieved by increased RR and short exhalation time was nearly equivalent to recruitment achieved by increased PEEPe. The short exhalation time at increased RR, however, did not generate PEEPi. Cardiac output was increased on average 13% in the high RR group compared with the high PEEPe group ( P < 0.001), and mixed venous saturation was consistently greater in the high RR group ( P < 0.001). Prevention of end-expiratory derecruitment without increased end-expiratory pressure suggests that another mechanism, distinct from intrinsic PEEP, plays a role in the dynamic behavior of atelectasis.

Respiratory measurements of cardiac output: from elegant idea to useful test

2004 ◽  
Vol 96 (2) ◽  
pp. 428-437 ◽  
Author(s):  
Gabriel Laszlo
Keyword(s):  
Cardiac Output ◽  
Human Subjects ◽  
Venous Blood ◽  
The Body ◽  
Mixed Venous Blood ◽  
Indirect Determination ◽  
Arterial Blood ◽  
Pulmonary Capillary ◽  
Pulmonary Arterial ◽  
Mixed Venous

The measurement of cardiac output was first proposed by Fick, who published his equation in 1870. Fick's calculation called for the measurement of the contents of oxygen or CO2 in pulmonary arterial and systemic arterial blood. These values could not be determined directly in human subjects until the acceptance of cardiac catheterization as a clinical procedure in 1940. In the meanwhile, several attempts were made to perfect respiratory methods for the indirect determination of blood-gas contents by respiratory techniques that yielded estimates of the mixed venous and pulmonary capillary gas pressures. The immediate uptake of nonresident gases can be used in a similar way to calculate cardiac output, with the added advantage that they are absent from the mixed venous blood. The fact that these procedures are safe and relatively nonintrusive makes them attractive to physiologists, pharmacologists, and sports scientists as well as to clinicians concerned with the physiopathology of the heart and lung. This paper outlines the development of these techniques, with a discussion of some of the ways in which they stimulated research into the transport of gases in the body through the alveolar membrane.

Comparison of cardiac output measurements using electrical velocimetry and lithium dilution with thermodilution in anesthetized dogs

2021 ◽  
Vol 48 (6) ◽  
pp. S997
Author(s):  
V. Paranjape ◽  
N. Henao-Guerrero ◽  
G. Menciotti ◽  
F. Garcia-Pereira ◽  
C. Ricco-Pereira
Keyword(s):  
Cardiac Output ◽  
Electrical Velocimetry ◽  
Anesthetized Dogs ◽  
Cardiac Output Measurements

Estimation of ventilation-perfusion inequality by inert gas elimination without arterial sampling

1985 ◽  
Vol 59 (2) ◽  
pp. 376-383 ◽  
Author(s):  
P. D. Wagner ◽  
C. M. Smith ◽  
N. J. Davies ◽  
R. D. McEvoy ◽  
G. E. Gale
Keyword(s):  
Cardiac Output ◽  
Venous Blood ◽  
Inert Gas ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Arterial Access ◽  
Arterial Blood ◽  
Potential Applications ◽  
Clinical Interest ◽  
Mixed Venous

Estimation of ventilation-perfusion (VA/Q) inequality by the multiple inert gas elimination technique requires knowledge of arterial, mixed venous, and mixed expired concentrations of six gases. Until now, arterial concentrations have been directly measured and mixed venous levels either measured or calculated by mass balance if cardiac output was known. Because potential applications of the method involve measurements over several days, we wished to determine whether inert gas levels in peripheral venous blood ever reached those in arterial blood, thus providing an essentially noninvasive approach to measuring VA/Q mismatch that could be frequently repeated. In 10 outpatients with chronic obstructive pulmonary disease, we compared radial artery (Pa) and peripheral vein (Pven) levels of the six gases over a 90-min period of infusion of the gases into a contralateral forearm vein. We found Pven reached 90% of Pa by approximately 50 min and 95% of Pa by 90 min. More importantly, the coefficient of variation at 50 min was approximately 10% and at 90 min 5%, demonstrating acceptable intersubject agreement by 90 min. Since cardiac output is not available without arterial access, we also examined the consequences of assuming values for this variable in calculating mixed venous levels. We conclude that VA/Q features of considerable clinical interest can be reliably identified by this essentially noninvasive approach under resting conditions stable over a period of 1.5 h.

Influence of changes in cardiac output on the acid-base status of arterial and mixed venous blood

1987 ◽  
Vol 410 (3) ◽  
pp. 257-262 ◽  
Author(s):  
Y. L. Hoogeveen ◽  
J. P. Zock ◽  
P. Rispens ◽  
W. G. Zijlstra
Keyword(s):  
Cardiac Output ◽  
Venous Blood ◽  
Mixed Venous Blood ◽  
Acid Base ◽  
Acid Base Status ◽  
Mixed Venous

Lactate, pyruvate, glucose, and free fatty acid in mixed venous and arterial blood

1963 ◽  
Vol 18 (5) ◽  
pp. 933-936 ◽  
Author(s):  
P. Harris ◽  
T. Bailey ◽  
M. Bateman ◽  
M. G. Fitzgerald ◽  
J. Gloster ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cardiac Output ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Venous Blood ◽  
Average Concentration ◽  
Mixed Venous Blood ◽  
Arterial Blood ◽  
Acquired Heart Disease ◽  
Mixed Venous

The concentrations of lactic acid, pyruvic acid, glucose, and free fatty acids have been measured simultaneously in the blood from the pulmonary and brachial arteries at rest and during exercise in a group of patients with acquired heart disease. The arteriovenous differences in the concentration of lactate, pyruvate, and free fatty acid were such as could be attributed to chance. The average concentration of glucose was slightly but significantly higher in the brachial arterial blood than in the mixed venous blood. cardiac output; lung metabolism; exercise Submitted on January 15, 1963

Influence of age and physical activity on central hemodynamics and lung function in active adults

1978 ◽  
Vol 45 (5) ◽  
pp. 709-717 ◽  
Author(s):  
I. L. Kanstrup ◽  
B. Ekblom
Keyword(s):  
Physical Activity ◽  
Maximal Exercise ◽  
Individual State ◽  
Vo2 Max ◽  
Physically Active ◽  
Circulatory Response ◽  
The Individual ◽  
Active Adults ◽  
Mixed Venous ◽  
Peak Value

Five female and seven male physically active adults were studied twice within a 13-yr interval. The individual state of physical activity was mainly unchanged. Maximal oxygen uptake (VO2 max) was reduced in all subjects except one female, in whom it remained unchanged. During maximal exercise, cardiac output (Q) in males was unchanged. In females, Q was significantly increased due to increased stroke volume (SV). In both sexes, the reduced VO2 max was explained by a smaller arteriovenous O2 difference (mixed venous O2 content (C-VO2) significantly increased). For a given submaximal VO2, Q was increased in both sexes and heart rate was unchanged. Thus, SV was increased and arteriovenous O2 difference was reduced due to increased C-VO2. Another four males were studied several times in various states of physical fitness during an 11-yr period. The reduced VO2 max from peak value was due to a reduced Qmax (SV smaller), whereas the arteriovenous O2 difference and C-VO2 were unchanged. Our results indicate that the observed changes in circulatory response to submaximal and maximal exercise in physically active adults may to a large extent be due to an effect of “detraining.”

Sign in / Sign up

Export Citation Format

Share Document