Cardiac output of dogs exercising in the heat

1984 ◽  
Vol 247 (1) ◽  
pp. R124-R126
Author(s):  
L. W. Chapman ◽  
M. A. Baker
Keyword(s):  
Cardiac Output ◽  
Ambient Temperature ◽  
High Ambient Temperature ◽  
Moderate Exercise ◽  
Heavy Exercise ◽  
Blood Temperature ◽  
Cool Conditions

We measured cardiac output and central blood temperature in five large dogs (27 kg mean body wt) running at 7.5 km/h for 30 min at two work loads and at low and high ambient temperature (Ta). Each animal ran on a level treadmill (O2 cost about 4 times that of resting) at 25 and 35 degrees C Ta and at a 20% slope (O2 cost about 10 times that of resting) at 25 and 35 degrees C Ta. Cardiac output (CO) was the same at 15 and 30 min of exercise at both work loads and both TaS. CO was higher at 35 degrees C Ta at both work loads. Blood temperature rose 0.6 degrees C during exercise on the level treadmill at 25 degrees C and stabilized after the 15th min of exercise. On the level treadmill at 35 degrees C, blood temperature increased by 1.9 degrees C after 30 min. During 30 min of running at 20% slope, blood temperature increased by 3.2 degrees C at 25 degrees C and by 4.6 degrees C at 35 degrees C. At these work loads the dog is able to increase CO during exercise in the heat. This response is similar to that of humans doing moderate exercise in the heat but is in contrast to that of humans doing heavy exercise in the heat, in whom CO shows a drop or no change compared with cool conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of exercise-induced hypoxemia in horses

1989 ◽  
Vol 66 (3) ◽  
pp. 1227-1233 ◽  
Author(s):  
P. D. Wagner ◽  
J. R. Gillespie ◽  
G. L. Landgren ◽  
M. R. Fedde ◽  
B. W. Jones ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Treadmill Exercise ◽  
Inert Gas ◽  
Diffusion Limitation ◽  
O2 Uptake ◽  
Heavy Exercise ◽  
Physiological Basis ◽  
Blood Temperature ◽  
Exercise Induced ◽  
Arterial Po2

Arterial hypoxemia has been reported in horses during heavy exercise, but its mechanism has not been determined. With the use of the multiple inert gas elimination technique, we studied five horses, each on two separate occasions, to determine the physiological basis of the hypoxemia that developed during horizontal treadmill exercise at speeds of 4, 10, 12, and 13–14 m/s. Mean, blood temperature-corrected, arterial PO2 fell from 89.4 Torr at rest to 80.7 and 72.1 Torr at 12 and 13–14 m/s, respectively, whereas corresponding PaCO2 values were 40.3, 40.3, and 39.2 Torr. Alveolar-arterial PO2 differences (AaDO2) thus increased from 11.4 Torr at rest to 24.9 and 30.7 Torr at 12 and 13–14 m/s. In 8 of the 10 studies there was no change in ventilation-perfusion (VA/Q) relationships with exercise (despite bronchoscopic evidence of airway bleeding in 3) and total shunt was always less than 1% of the cardiac output. Below 10 m/s, the AaDO2 was due only to VA/Q mismatch, but at higher speeds, diffusion limitation of O2 uptake was increasingly evident, accounting for 76% of the AaDO2 at 13–14 m/s. Most of the exercise-induced hypoxemia is thus the result of diffusion limitation with a smaller contribution from VA/Q inequality and essentially none from shunting.

scholarly journals High ambient temperature and child emergency and hospital visits in New York City

2021 ◽  
Author(s):  
Li Niu ◽  
Maria Teresa Herrera ◽  
Blean Girma ◽  
Bian Liu ◽  
Leah Schinasi ◽  
...  
Keyword(s):  
New York ◽  
New York City ◽  
Ambient Temperature ◽  
York City ◽  
High Ambient Temperature ◽  
Hospital Visits

PSVII-24 Blend of essential oils plus 25-hydroxy-vitamin-D3 as alternative to the use monensin on growth performance and dietary energetics in feedlot cattle raised under high ambient temperature

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 452-453
Author(s):  
Daniel Mendoza-Cortés ◽  
Jorge L Ramos-Méndez ◽  
Adrián Félix-Bernal ◽  
Alfredo Estrada-Angulo ◽  
Manuel Franco ◽  
...  
Keyword(s):  
Essential Oils ◽  
Ambient Temperature ◽  
Vitamin D3 ◽  
Animal Health ◽  
Average Daily Gain ◽  
Feedlot Cattle ◽  
High Ambient Temperature ◽  
Energy Utilization ◽  
Daily Weight Gain ◽  
Final Weight

Abstract Ninety young crossbreed bulls (approximately 25% Zebu breeding with the remainder represented by continental and British breeds in various proportions, initial weight=228.04±7.06 kg) were used in a 84-day feeding trial to assess the effects of treatments in feedlot cattle fed transition diets during high ambient temperatures. Treatments consisted of a steam-flaked corn-based diets (average 1.95 Mcal ENm/kg) supplemented with: 1) 20 mg monensin/kg diet (MON, Rumensin, Elanco Animal Health, Indianapolis, IN], and 2) 100 mg of blend of essential oils /kg diet plus 0.1 mg 25-hydroxy-vitamin-D3/kg diet (EO+HyD; CRINA® Ruminants and HyD®, DSM Nutritional Products, Basel, Switzerland). Both dry matter intake (DMI) and climatic variables were measured daily and the temperature humidity index (THI) was estimated. Daily maximal THI remained over 80 during the whole trial (avg. THI = 82.67). Cattle supplemented with EO+HyD increased average daily gain in 8.7% (1.446 vs. 1.320 kg/day, P < 0.01), gain-to-fed ratio in 4.5% (0.199 vs. 0.190; P = 0.03), final weight in 10.05 kg (349.48 vs. 339.43; P = 0.04) and tended (P = 0.07) to shown greater dietary net energy (2.5%) and observed-to-expected dietary NE ratio (3%). Even when EO+HyD tended to increase (4.3%; P = 0.06) DM intake, intake pattern variation were not different (P = 0.38) between MON and EO+HyD (Figure 1). Then, difference in ADG and final BW between MON and EO+HyD was not only a reflection of difference in energy intake, was also caused by difference in efficiency of energy utilization during conditions of high ambient temperature (a reduction of 7% in the estimated increase of coefficient of maintenance by heat load). Results indicate that supplementation with a combination of essential oil blend plus 25-hydroxy-vitamin-D3 can have greater beneficial effects than supplemental monensin on daily weight gain, final weight and feed intake during initiation-transition phase of cattle raised under high ambient temperature.

546 Management of Pediatric Pavement Burns

2021 ◽  
Vol 42 (Supplement_1) ◽  
pp. S121-S122
Author(s):  
Syed F Saquib ◽  
Paul J Chestovich ◽  
Joseph T Carroll ◽  
Carmen E Flores
Keyword(s):  
Ambient Temperature ◽  
Average Length ◽  
Topical Therapy ◽  
Total Body Surface Area ◽  
High Ambient Temperature ◽  
Unknown Etiology ◽  
Oral Antibiotic ◽  
Superficial Infection ◽  
Plantar Aspect

Abstract Introduction Pavement burns are common in a dry high heat climate. This study reviews the etiology, management and outcome of pavement burns in children. Methods All patients age < 18 who suffered contact burns from hot pavement from Jan 1, 2014 to Dec 31, 2019 were reviewed. A total of 45 patient charts met inclusion criteria. High ambient temperature on each date, and zip code of each injury was extracted from Weather Underground (www.wunderground.com) Results In this study, 45 patients met criteria and were reviewed, of whom 27 patients (60%) were male. Average age was 3.29 years (SD 0.69), made up two discrete age groups: age under 3 (n= 40, 89%) and 14+ (n=5, 11%). 38 patients (84%) had no known medical history. All had 2nd degree burns and one patient (2%) had third degree burns. Mean total body surface area (TBSA) was 2.5% (SD 1.4%, range 0.75% to 5.5%). Burn etiology included 31 patients (69%) walking barefoot on pavement, 6 (13%) falling onto pavement, and other/unknown etiology for the remaining 8 patients (18%). 30 patients (67%) had injuries on the plantar aspect of bilateral feet, 2 (4%) to bilateral palms of hands, 4 (9%) to other parts of upper extremities and 10 (22%) to other parts of lower extremities. Thirty-four (34) patients (76%) were managed without any hospitalization. Those that were hospitalized had an average length of stay (LOS) of 2.72 days (range 1–9 days). All burns were managed non-operatively with topical therapy alone. 35 patients (78%) were managed initially with Silvadene, and 6 (13%) with bacitracin. Aquacel was utilized in 10 patients at a follow-up visit (22%). Three patients (6.7%) were treated with collagenase enzyme therapy. One patient developed a superficial infection requiring oral antibiotic therapy. There were no mortalities in this group. The high ambient temperature on date and location of each injury was 101 F (SD 1.10 F, range 73F-111F). Of the thirty that continued to follow up in clinic, the average time to the burn being 95% healed was 10.50 days (SD 8.97 days, range 2–40 days). Conclusions Pavement burns in children are partial thickness and are safely managed with topical therapy alone, with good outcomes. Patients age 3 and under are a vulnerable population and therefore at particular risk of injury.

Pulmonary gas exchange in humans during exercise at sea level

1986 ◽  
Vol 60 (5) ◽  
pp. 1590-1598 ◽  
Author(s):  
M. D. Hammond ◽  
G. E. Gale ◽  
K. S. Kapitan ◽  
A. Ries ◽  
P. D. Wagner
Keyword(s):  
Gas Exchange ◽  
Sea Level ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Inert Gas ◽  
Diffusion Limitation ◽  
O2 Uptake ◽  
Heavy Exercise ◽  
Blood Temperature ◽  
O2 Diffusion

Previous studies have shown both worsening ventilation-perfusion (VA/Q) relationships and the development of diffusion limitation during exercise at simulated altitude and suggested that similar changes could occur even at sea level. We used the multiple-inert gas-elimination technique to further study gas exchange during exercise in healthy subjects at sea level. Mixed expired and arterial respiratory and inert gas tensions, cardiac output, heart rate, minute ventilation, respiratory rate, and blood temperature were recorded at rest and during steady-state exercise in the following order: rest, minimal exercise (75 W), heavy exercise (300 W), heavy exercise breathing 100% O2, repeat rest, moderate exercise (225 W), and light exercise (150 W). Alveolar-to-arterial O2 tension difference increased linearly with O2 uptake (VO2) (6.1 Torr X min-1 X 1(-1) VO2). This could be fully explained by measured VA/Q inequality at mean VO2 less than 2.5 l X min-1. At higher VO2, the increase in alveolar-to-arterial O2 tension difference could not be explained by VA/Q inequality alone, suggesting the development of diffusion limitation. VA/Q inequality increased significantly during exercise (mean log SD of perfusion increased from 0.28 +/- 0.13 at rest to 0.58 +/- 0.30 at VO2 = 4.0 l X min-1, P less than 0.01). This increase was not reversed by 100% O2 breathing and appeared to persist at least transiently following exercise. These results confirm and extend the earlier suggestions (8, 21) of increasing VA/Q inequality and O2 diffusion limitation during heavy exercise at sea level in normal subjects and demonstrate that these changes are independent of the order of performance of exercise.

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