Breathing pattern affects respiratory heat loss but not bronchoconstrictor response in asthma

Lung ◽  
1990 ◽  
Vol 168 (1) ◽  
pp. 23-34 ◽  
Author(s):  
E. P. Ingenito ◽  
B. M. Pichurko ◽  
J. Lafleur ◽  
J. M. Drazen ◽  
R. H. Ingram ◽  
...  
Keyword(s):  
Heat Loss ◽  
Breathing Pattern ◽  
Respiratory Heat Loss

Cold-induced changes in breathing pattern as a strategy to reduce respiratory heat loss

1990 ◽  
Vol 69 (6) ◽  
pp. 1946-1952 ◽  
Author(s):  
D. A. Diesel ◽  
A. Tucker ◽  
D. Robertshaw
Keyword(s):  
Heat Loss ◽  
Air Temperature ◽  
Cold Exposure ◽  
Breathing Pattern ◽  
Ventilatory Response ◽  
Respiratory Frequency ◽  
Hypothalamic Temperature ◽  
Respiratory Heat Loss ◽  
Induced Changes ◽  
Expired Air

Thermoregulatory benefits of cold-induced changes in breathing pattern and mechanism(s) by which cold induces hypoventilation were investigated using male Holstein calves (1-3 mo old). Effects of ambient temperatures (Ta) between 4 and 18 degrees C on ventilatory parameters and respiratory heat loss (RHL) were determined in four calves. As Ta decreased, respiratory frequency decreased 29%, tidal volume increased 35%, total ventilation and RHL did not change, and the percentage of metabolic rate attributed to RHL decreased 26%. Total ventilation was stimulated by increasing inspired CO2 in six calves (Ta 4-6 degrees C), and a positive relationship existed between respiratory frequency and expired air temperature. Therefore, cold-exposed calves conserve respiratory heat by decreasing expired air temperature and dead space ventilation. Compared with thermoneutral exposure (16-18 degrees C), hypoventilation was induced by airway cold exposure (4-6 degrees C) alone and by exposing the body but not the airways to cold. Blocking nasal thermoreceptors with topical lidocaine during airway cold exposure prevented the ventilatory response but did not lower hypothalamic temperature. Hypothalamic cooling (Ta 16-18 degrees C) did not produce a ventilatory response. Thus, airway temperature but not hypothalamic temperature appears to control ventilation in cold-exposed calves.

Respiratory water and heat loss of the black duck during flight at different ambient temperatures

1971 ◽  
Vol 49 (5) ◽  
pp. 767-774 ◽  
Author(s):  
M. Berger ◽  
J. S. Hart ◽  
O. Z. Roy
Keyword(s):  
Heat Loss ◽  
Water Loss ◽  
Pulmonary Ventilation ◽  
Evaporative Heat Loss ◽  
Total Heat Loss ◽  
Ambient Temperatures ◽  
Black Duck ◽  
Respiratory Heat Loss ◽  
Metabolic Water ◽  
Expired Air

Pulmonary ventilation and temperature of expired air and of the respiratory passages has been measured by telemetry during flight in the black duck (Anas rubripes) and the respiratory water and heat loss has been calculated.During flight, temperature of expired air was higher than at rest and decreased with decreasing ambient temperatures. Accordingly, respiratory water loss as well as evaporative heat loss decreased at low ambient temperatures, whereas heat loss by warming of the inspired air increased. The data indicated respiratory water loss exceeded metabolic water production except at very low ambient temperatures. In the range between −16 °C to +19 °C, the total respiratory heat loss was fairly constant and amounted to 19% of the heat production. Evidence for the independence of total heat loss and production from changes in ambient temperature during flight is discussed.

Longitudinal distribution of canine respiratory heat and water exchanges

1989 ◽  
Vol 66 (6) ◽  
pp. 2788-2798 ◽  
Author(s):  
D. W. Ray ◽  
E. P. Ingenito ◽  
M. Strek ◽  
P. T. Schumacker ◽  
J. Solway
Keyword(s):  
Heat Loss ◽  
Wall Temperature ◽  
Minute Ventilation ◽  
Local Heat ◽  
Longitudinal Distribution ◽  
Evaporative Heat Loss ◽  
Airway Wall ◽  
Gas Temperature ◽  
Dry Air ◽  
Respiratory Heat Loss

We assessed the longitudinal distribution of intra-airway heat and water exchanges and their effects on airway wall temperature by directly measuring respiratory fluctuations in airstream temperature and humidity, as well as airway wall temperature, at multiple sites along the airways of endotracheally intubated dogs. By comparing these axial thermal and water profiles, we have demonstrated that increasing minute ventilation of cold or warm dry air leads to 1) further penetration of unconditioned air into the lung, 2) a shift of the principal site of total respiratory heat loss from the trachea to the bronchi, and 3) alteration of the relative contributions of conductive and evaporative heat losses to local total (conductive plus evaporative) heat loss. These changes were not accurately reflected in global measurements of respiratory heat and water exchange made at the free end of the endotracheal tube. Raising the temperature of inspired dry air from frigid to near body temperature principally altered the mechanism of airway cooling but did not influence airway mucosal temperature substantially. When local heat loss was increased from both trachea and bronchi (by increasing minute ventilation), only the tracheal mucosal temperature fell appreciably (up to 4.0 degrees C), even though the rise in heat loss from the bronchi about doubled that in the trachea. Thus it appears that the bronchi are better able to resist changes in airway wall temperature than is the trachea. These data indicate that the sites, magnitudes, and mechanisms of respiratory heat loss vary appreciably with breathing pattern and inspired gas temperature and that these changes cannot be predicted from measurements made at the mouth. In addition, they demonstrate that local heat (and presumably, water) sources that replenish mucosal heat and water lost to the airstream are important in determining the degree of local airway cooling (and presumably, drying).

Effects of carbon dioxide on cold-exposed human subjects

1961 ◽  
Vol 16 (4) ◽  
pp. 633-638 ◽  
Author(s):  
Robert W. Bullard ◽  
John R. Crise
Keyword(s):  
Carbon Dioxide ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Human Subjects ◽  
Respiratory Heat Loss ◽  
Time Periods

Human subjects were exposed to an ambient temperature of 5 C for 75-min periods. Subjects breathed 2.5%—6% carbon dioxide for selected time periods during the exposure. Carbon dioxide appeared to inhibit shivering. After carbon dioxide inhalation, shivering and metabolism were greatly increased. When 6% carbon dioxide was inhaled for 30 min, the inhibition was overcome and shivering and metabolism approached high levels. The increased respiratory heat loss associated with carbon dioxide breathing may be one factor causing the breakthrough of the inhibition. Submitted on November 14, 1960

scholarly journals Exercise-induced asthma without respiratory heat loss

Thorax ◽  
1983 ◽  
Vol 38 (4) ◽  
pp. 320-320 ◽  
Author(s):  
D. Godden ◽  
S. Jamieson ◽  
T. Higenbottam
Keyword(s):  
Heat Loss ◽  
Respiratory Heat Loss ◽  
Exercise Induced

Relationship between respiratory heat loss, panting rate and body temperature in conscious ducks under heat stress

1982 ◽  
Vol 394 (S1) ◽  
pp. R37-R37 ◽  
Author(s):  
Elisabeth Geisthövel ◽  
Eckhart Simon
Keyword(s):  
Heat Stress ◽  
Body Temperature ◽  
Heat Loss ◽  
Respiratory Heat Loss

Respiratory heat loss and core temperatures during submaximal exercise

1995 ◽  
Vol 20 (6) ◽  
pp. 489-496 ◽  
Author(s):  
Matthew D. White ◽  
Michel Cabanac
Keyword(s):  
Heat Loss ◽  
Submaximal Exercise ◽  
Respiratory Heat Loss

Respiratory heat loss in the sheep: a comprehensive model

2002 ◽  
Vol 46 (3) ◽  
pp. 136-140 ◽  
Author(s):  
Roberto Gomes da Silva ◽  
Newton LaScala ◽  
Alvaro Lima Filho ◽  
Marcelo Catharin
Keyword(s):  
Heat Loss ◽  
Comprehensive Model ◽  
Respiratory Heat Loss

Finite difference analysis of respiratory heat transfer

1986 ◽  
Vol 61 (6) ◽  
pp. 2252-2259 ◽  
Author(s):  
E. P. Ingenito ◽  
J. Solway ◽  
E. R. McFadden ◽  
B. M. Pichurko ◽  
E. G. Cravalho ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Air Temperature ◽  
Breathing Pattern ◽  
Human Subjects ◽  
Minute Ventilation ◽  
Tracheobronchial Tree ◽  
Temperature Profiles ◽  
Opposite Pattern ◽  
Normal Human

A numerical computer model of heat and water transfer within the tracheobronchial tree of humans was developed based on an integral formulation of the first law of thermodynamics. Simulation results were compared with directly measured intraluminal airway temperature profiles previously obtained in normal human subjects, and a good correlation was demonstrated. The model was used to study aspects of regional pulmonary heat transfer and to predict the outcomes of experiments not yet performed. The results of these simulations show that a decrease in inspired air temperature and water content at fixed minute ventilation produces a proportionately larger increase in heat loss from extrathoracic airways relative to intrathoracic, whereas an increase in minute ventilation at fixed inspired air conditions produces the opposite pattern, with cold dry air penetrating further into the lung, and that changes in breathing pattern (tidal volume and frequency) at fixed minute ventilation and fixed inspiratory-to-expiratory (I/E) ratio do not affect local air temperature profiles and heat loss, whereas changes in I/E ratio at fixed minute ventilation do cause a significant change.

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