Cardiovascular and respiratory responses to heat in dehydrated dogs

1984 ◽  
Vol 246 (3) ◽  
pp. R369-R374 ◽  
Author(s):  
M. A. Baker
Keyword(s):  
Blood Flow ◽  
Body Weight ◽  
Cardiac Output ◽  
Ambient Temperature ◽  
Rectal Temperature ◽  
Respiratory Frequency ◽  
Carotid Blood Flow ◽  
Ambient Temperatures ◽  
Upper Respiratory ◽  
Respiratory Evaporation

The effect of dehydration on rectal temperature, respiratory frequency, upper respiratory evaporation, cardiac output, and common carotid blood flow was studied in large mongrel dogs at rest at ambient temperatures between 25 and 45 degrees C. Measurements were made in animals hydrated ad libitum and when they had been dehydrated by removal of drinking water. In hydrated animals, mean body weight was 31.6 +/- 1.7 (SE) kg and plasma osmolality was 296 +/- 2 mosmol/kg H2O. Dehydration decreased body weight to 28.2 +/- 1.5 kg and increased osmolality to 328 +/- 5 mosmol/kg H2O. At all ambient temperatures, every dehydrated animal had a higher rectal temperature, lower respiratory frequency, lower upper respiratory evaporation, lower cardiac output, and lower common carotid blood flow. Rectal temperature, measured in seven animals, was constant as ambient temperature was raised from 25 to 45 degrees C in both the hydrated and dehydrated state, but was elevated by 0.72 degrees C in dehydrated animals. Hypothalamic temperature, measured in two animals, was elevated less than rectal temperature when they were dehydrated. Upper respiratory evaporation and respiratory frequency, measured in seven animals, increased with increasing ambient temperature in both the hydrated and the dehydrated dogs, but were lower at every ambient temperature in dehydrated animals. Cardiac output, measured in five animals, was lower in dehydrated animals at every ambient temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Thermoregulatory responses to exercise in dehydrated dogs

1984 ◽  
Vol 56 (3) ◽  
pp. 635-640 ◽  
Author(s):  
M. A. Baker
Keyword(s):  
Blood Flow ◽  
Drinking Water ◽  
Body Weight ◽  
Cardiac Output ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Rectal Temperature ◽  
Initial Body Weight ◽  
Ad Libitum ◽  
Made In

Measurements of rectal temperature (Tre), water lost by evaporation (Eresp) and drooling, cardiac output (CO), and common carotid blood flow (CCBF) were made in dogs (mean hydrated wt 31.0 +/- 1.5 kg) running for 1 h on a level treadmill at 7.5 km/h at an ambient temperature of 25 degrees C. Each animal was studied when it was hydrated ad libitum and when it had been dehydrated by removal of drinking water until 9–10% of the initial body weight had been lost. Dehydrated exercising animals had significantly higher Tre and lower rates of Eresp, CO, and CCBF. Tre and Eresp were measured in seven animals. Average Tre during running was 39.11 +/- 0.10 degrees C in hydrated and 39.80 +/- 0.25 degrees C in dehydrated animals (P less than 0.01). Average Eresp during running was 3.9 +/- 0.3 g/min in hydrated animals and 2.3 +/- 0.3 g/min in dehydrated animals (P less than 0.01). Average CO during exercise, measured in five animals, was 11.1 +/- 0.7 1/min in the hydrated state and 8.6 +/- 0.5 1/min in the dehydrated state (P less than 0.01). Unilateral CCBF during exercise, measured in four animals, was 602 +/- 40 ml/min in the hydrated state and 418 +/- 22 ml/min in the dehydrated state (P less than 0.01). Water lost by drooling in seven exercising animals was 41.5 +/- 11 g/h when they were hydrated and 0.6 +/- 0.4 g/h when they were dehydrated. It is concluded that dehydrated dogs doing mild exercise can save water by reducing Eresp and regulating body temperature above hydrated levels.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Correlation of Carotid Blood Flow and Carotid Flow Time With Invasive Cardiac Output Measurements

CHEST Journal ◽  
2016 ◽  
Vol 150 (4) ◽  
pp. 297A
Author(s):  
Irene Ma ◽  
Joshua Caplin ◽  
Aftab Azad ◽  
Christina Wilson ◽  
Michael Fifer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Flow Time ◽  
Carotid Blood Flow ◽  
Cardiac Output Measurements ◽  
Carotid Flow

Effect of Changes in Ambient Temperature on Spontaneous Activity, Food Intake and Body Weight of Goldthioglucose-Obese and Nonobese Mice

1957 ◽  
Vol 188 (3) ◽  
pp. 435-438 ◽  
Author(s):  
M. J. Fregly ◽  
N. B. Marshall ◽  
J. Mayer
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Ambient Temperature ◽  
The Body ◽  
Lower Body ◽  
Obese Mice ◽  
Ambient Temperatures ◽  
Exposure To Cold ◽  
Running Activity ◽  
Body Weights

Goldthioglucose-obese mice cannot adjust their food intake to meet the increased energy requirements due to cold. At all ambient temperatures above 15°C the spontaneous running activity of these animals is less than that observed for nonobese controls. Activity of obese mice is maximal at 19°C and minimal at 15°C or lower. Body weights decrease during exposure to cold. In contrast to that of obese mice, running activity of nonobese controls is maximal at an ambient temperature of 25°C but nearly ceases at 15°C or lower. The food intake of these animals increases in the cold and remains elevated even at temperatures at which activity decreases. The body weight of nonobese controls is either maintained constant or increases during exposure to cold air.

The metabolic rates of newborn pigs in relation to floor insulation and ambient temperature

1971 ◽  
Vol 13 (2) ◽  
pp. 303-313 ◽  
Author(s):  
D. B. Stephens
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Regression Coefficients ◽  
Metabolic Rates ◽  
Similar Treatment ◽  
Concrete Floor ◽  
Ambient Temperatures ◽  
Newborn Pigs ◽  
Floor Material

SUMMARY1. The metabolic rates of 58 individual piglets kept either on a straw or on a concrete floor at ambient temperatures near to 10°, 20° or 30°C have been measured with ages ranging from newborn to 9 days, and body weight from 1·0 to 3·2 kg. The oxygen consumption was measured on each floor material at the chosen ambient temperature thus allowing paired comparisons for each animal.2. In comparison with the concrete floor, oxygen consumption on straw was reduced by 18% at 10°C, 27% at 20°C and by 12% at 30°C for pigs 2 to 9 days old. The regression coefficients of mean log (oxygen consumption) on log (body weight) were around 0·66 at 10° and 20°C. At 30°C the value was 0·99 ± 0·14. The regression coefficients were not significantly affected by the presence of a straw floor showing that its effect did not vary with body weight. Corresponding values foi piglets below 24 hours of age were 17% at 10°C, 27% at 20°C and 22% at 30°C ambient temperature.3. Moving a piglet on to a straw floor at 10°C had the same thermal effect as raising the ambient temperature to 18°C. Similar treatment at 30°C was equivalent to raising the ambient temperature to 32°C.4. Lowering ambient temperature to increase the temperature gradient between the homeothermic body of the piglet and the environment progressively increased heat loss in all cases. There was a concomitant decrease in the calculated conductance between core and environment which was more pronounced for the piglets lying on the concrete floor.

Responses of young calves to low ambient temperatures at two levels of feeding

1992 ◽  
Vol 55 (3) ◽  
pp. 397-405 ◽  
Author(s):  
J. W. Schrama ◽  
A. Arieli ◽  
M. J. W. Heetkamp ◽  
M. W. A. Verstegen
Keyword(s):  
Energy Metabolism ◽  
Ambient Temperature ◽  
Rectal Temperature ◽  
Heat Production ◽  
Experimental Period ◽  
Metabolizable Energy ◽  
Ambient Temperatures ◽  
Feeding Level ◽  
Holstein Friesian ◽  
Maintenance Requirements

AbstractSeven groups of five or six Holstein-Friesian male calves were transported to an experimental farm at 2 to 3 days of age. At 6 days of age, heat production (HP) and metabolizable energy (ME) intake were measured for an 8-day period. During this period, calves were exposed to various ambient temperatures: 6, 9, 12 and 15°C. Ambient temperature was constant within days, but changed between days. Calves were fed below (four groups) or near (three groups) the maintenance requirements (290 or 460 kJ ME per kg M0·75 per day).From 6 to 14 days of age the lower critical temperature (Tc) was 12·5°C and HP increased by 8·4 kJ/kg M0·75 per day per °Cfall in ambient temperature below Tc. Both Tc and increase in HP below Tc were not affected by feeding level. Rectal temperature was lower at low ambient temperatures. The decrease in rectal temperature with ambient temperature was greatest at the low feeding level.During the experimental period, calves were not in a steady-state regarding energy metabolism. Heat production decreased with time. This decrease was affected by feeding level and ambient temperature. After arrival, the influence of both ambient temperature and feeding level on the energy metabolism of young calves increased with time.

Fluid replacement and glucose infusion during exercise prevent cardiovascular drift

1991 ◽  
Vol 71 (3) ◽  
pp. 871-877 ◽  
Author(s):  
M. T. Hamilton ◽  
J. Gonzalez-Alonso ◽  
S. J. Montain ◽  
E. F. Coyle
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Cardiac Output ◽  
Rectal Temperature ◽  
Prolonged Exercise ◽  
Blood Glucose Concentration ◽  
Fluid Replacement ◽  
O2 Uptake ◽  
Trained Subjects ◽  
Cardiovascular Drift

This study examined the influence of both hydration and blood glucose concentration on cardiovascular drift during exercise. We first determined if the prevention of dehydration during exercise by full fluid replacement prevents the decline in stroke volume (SV) and cardiac output (CO) during prolonged exercise. On two occasions, 10 endurance-trained subjects cycled an ergometer in a 22 degrees C room for 2 h, beginning at 70 +/- 1% maximal O2 uptake (VO2max) and in a euhydrated state. During one trial, no fluid (NF) replacement was provided and the subject's body weight declined 2.09 +/- 0.19 kg or 2.9%. During the fluid replacement trial (FR), water was ingested at a rate that prevented body weight from declining after 2 h of exercise (i.e., 2.34 +/- 0.17 1/2 h). SV declined 15% and CO declined 7% during the 20- to 120-min period of the NF trial while heart rate (HR) increased 10% and O2 uptake (VO2) increased 6% (all P less than 0.05). In contrast, SV was maintained during the 20- to 120-min period of FR while HR increased 5% and thus CO actually increased 7% (all P less than 0.05). Rectal temperature, SV, and HR were similar during the 1st h of exercise during NF and FR. However, after 2 h of exercise, rectal temperature was 0.6 degree C higher (P less than 0.05) and SV and CO were 11–16% lower (P less than 0.05) during NF compared with FR.(ABSTRACT TRUNCATED AT 250 WORDS)

DISTRIBUTION OF BLOOD FLOW IN COLD STRESSED PIGLETS

1979 ◽  
Vol 59 (4) ◽  
pp. 721-726 ◽  
Author(s):  
P. E. V. WILLIAMS ◽  
R. O. PARKER ◽  
B. A. YOUNG ◽  
F. X. AHERNE
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Cold Stress ◽  
Rectal Temperature ◽  
Cold Exposure ◽  
Alimentary Tract ◽  
Distribution Of Cardiac Output

Radioactive ruthenium labelled microspheres 15 ± 3 μm in diameter were used to determine distribution of cardiac output in unfed control (35 °C) and unfed cold stressed (5 °C) piglets 3.5 h of age. The cold stress produced an average 7.1 °C drop in rectal temperature and a redistribution of blood flow. In cold exposed piglets the adrenal fraction of cardiac output was significantly (P < 0.05) lower: 0.56% in the control compared with 0.29% in the cold exposed piglets; however, the relative blood flow to the adrenals was higher than for other tissues. The fractions of cardiac output reaching the psoas and biceps muscles increased (P < 0.05) by 148 and 260%, respectively, during cold exposure, while that reaching the heart, brain, alimentary tract, skin and fat was not significantly (P > 0.05) affected by cold exposure.

Abstract 2059: Transthoracic Application of Medium Voltage Therapy Maintains Forward Blood Flow during Cardiac Arrest

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Giuseppe Ristagno ◽  
Yongqin Li ◽  
Hao Wang ◽  
Shijie Sun ◽  
Gilman Byron ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Arrest ◽  
Cardiac Output ◽  
Ejection Fraction ◽  
Stroke Volume ◽  
Chest Compression ◽  
Entire Interval ◽  
Carotid Blood Flow ◽  
Medium Voltage ◽  
Threshold Levels

We have previously reported that transthoracic medium voltage therapy (MVT) generated coronary perfusion pressure (CPP), forward carotid blood flow (CBF) and end-tidal CO 2 (EtCO 2 ) comparable to those produced by manual chest compression. In the present study, we investigated the capability of MVT to generate and maintain forward blood flow for a longer interval, i.e. 1 min, in a porcine model of short duration cardiac arrest. MVT can maintain threshold levels of CPP, CBF and EtCO 2 , for a minute interval prior to defibrillation. In 7 domestic male pigs weighing 40 ± 1 kg, VF was electrically induced and untreated for 10 seconds. Animals were then subjected to receive MVT for one minute with the aid of a Galvani E-CPR device (Galvani Ltd, Edina, MN), after when a biphasic shock was delivered. The MVT pulsed packet was 400 msec, the pulsed packet rate was 80/min, the intra-packet pulse period was 25 ms and intra-packet pulse durations were 0.2 ms. CPP and EtCO2 were continuously measured during MVT. CBF and ejection fraction generated during MVT were measured by echo-Doppler technique, while cardiac output with stroke volume by thermodiluition method. MVT was able to maintain CPP and EtCO2 above the threshold levels for successful resuscitation for the entire interval of application (Table ). During MVT, excellent stroke volume, cardiac output and ejection fraction together with carotid blood flow were generated (Table ). MVT produced and maintained for one minute forward blood flow during cardiac arrest. This electrical therapy might represent a new approach intended to generate and/or maintain forward blood flow in lieu of or in association with chest compression in victims of cardiac arrest

Skin temperature and blood flow in the rabbit ear

1963 ◽  
Vol 204 (4) ◽  
pp. 615-618 ◽  
Author(s):  
N. Honda ◽  
L. D. Carlson ◽  
W. V. Judy
Keyword(s):  
Blood Flow ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Rectal Temperature ◽  
Peripheral Blood ◽  
Room Temperature ◽  
Peripheral Blood Flow ◽  
Rabbit Ear

The relation of skin temperature and blood flow in the rabbit ear may be expressed as (See PDF for Equation) where Ts is skin temperature, F is peripheral blood flow, TR is rectal temperature, Tr is room temperature, and K1, K2, K3, and α are constants. The constants vary with ambient temperature probably reflecting the degree of precooling that occurs in the circulating blood.

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