Thermoregulatory responses of febrile sheep to spinal and hypothalamic heating

1987 ◽  
Vol 253 (6) ◽  
pp. R868-R876 ◽  
Author(s):  
C. M. Blatteis ◽  
R. Necker ◽  
J. R. Hales ◽  
A. A. Fawcett ◽  
K. Hirata
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
O2 Consumption ◽  
Plateau Phase ◽  
Lower Range ◽  
Ambient Temperatures ◽  
Hypothalamic Thermosensitivity ◽  
The Mean ◽  
Conscious Sheep ◽  
Skin Temperatures

Fever was induced by the intravenous injection of 0.25 microgram/kg of lipopolysaccharide (LPS) from Escherichia coli in eight conscious sheep exposed to ambient temperatures adjusted to the lower range of thermoneutrality. Chronic spinal or hypothalamic thermodes were perfused with water of 44 degrees C for 20 min or for most of the rising phase of fever (100 min of the mean 166 min total rise time). The effects of spinal and hypothalamic heating were identical. Thus, before LPS, spinal or hypothalamic heating did not affect the rate of O2 consumption (VO2) but increased skin blood flow (as indicated by skin temperatures) and elicited panting; therefore rectal temperature (Tre) fell. During fever rise, the already reduced skin blood flow and respiratory rate were not affected by spinal or hypothalamic heating, but the increased VO2 was reduced; consequently, the rise in Tre was attenuated. During the plateau phase of fever, all responses were similar to those seen before LPS. In febrilysis, heating strongly enhanced the operating heat loss mechanisms and, hence, augmented the fall in Tre. Thus, although the thermoeffectors activated by spinal or hypothalamic heating were modified during the different stages of fever, the effect on body temperature was nearly the same. Therefore there seems to be no change in spinal or hypothalamic thermosensitivity during fever in sheep.

Control of skin blood flow in the neutral zone of human body temperature regulation

1996 ◽  
Vol 80 (4) ◽  
pp. 1249-1257 ◽  
Author(s):  
M. V. Savage ◽  
G. L. Brengelmann
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Inverse Relationship ◽  
Forearm Blood Flow ◽  
Wave Pattern ◽  
The Body ◽  
Reflex Response ◽  
Neutral Zone ◽  
Human Body Temperature ◽  
Skin Temperatures

In humans, matching of heat loss and heat production in the “neutral” zone, defined operationally in terms of a range of skin temperatures (Tsk), is accomplished by regulation of skin blood flow (SkBF). Our studies were designed to reveal the characteristics of control of SkBF [from measurements of forearm blood flow (FBF)] in this zone. We controlled the temperature of water sprayed on most of the body of supine men and women at 33 or 35 degrees C in a square-wave pattern (15 min at each temperature) or a step pattern (60 min at 33 degrees C separated by short periods at 35 degrees C). FBF followed Tsk (0.5 ml.min-1.degrees C-1). Esophageal temperature changed approximately 0.11 degrees C with each 2 degrees C change in Tsk, falling with Tsk increase and vice versa. Little influence on FBF, < 0.1 ml.min-1.100 ml-1. degrees C-1, was observed when only the forearm was sprayed with 33 and 35 degrees C water. We conclude that SkBF control in the 33-35 degree C range of Tsk is dominated by the feedforward reflex influence of Tsk on SkBF. The reflex response overcompensates for the effect of Tsk on thermal balance in the neutral zone, so that equilibrium core temperature has an inverse relationship to Tsk.

Skin Oxygen Permeability in Premature Infants

PEDIATRICS ◽  
1978 ◽  
Vol 62 (4) ◽  
pp. 488-491
Author(s):  
Hans T. Versmold ◽  
Mathäus Holzmann ◽  
Otwin Linderkamp ◽  
Klaus P. Riegel
Keyword(s):  
Blood Flow ◽  
Premature Infants ◽  
Oxygen Diffusion ◽  
Oxygen Permeability ◽  
Newborn Infants ◽  
Skin Surface ◽  
The Mean ◽  
Arterial Po2 ◽  
Skin Temperatures ◽  
Transcutaneous Po2

While 24 newborn infants (ages, 2 to 48 hours; gestational ages, 24 to 42 weeks) breathed various concentrations of oxygen, the PO2 values on their unheated skin surface were measured by an unheated microcathode electrode for transcutaneous PO2 monitoring. In infants with arterial PO2 values in the range of 50 to 100 torr and with similar skin temperatures, the mean surface PO2 of unheated skin was inversely related to birth weight: 27.2 torr in infants weighing less than 1,500 gm, 14.3 torr in infants weighing 1,500 to 2,500 gm, and 2.9 torr in infants weighing more than 2,500 gm. In the smallest infants, the skin surface PO2 was significantly related to arterial P02: it was about one third of arterial PO2 as estimated by a second electrode for transcutaneous PO2 monitoring heated to 44°C. Phototherapy, crying, or blood transfusion increased the surface P02 of unheated skin, but not the tcPO2 measured at 44°C. These findings suggest that blood flow to the skin in excess of its metabolic needs due to immature control of cutaneous circulation, along with low resistance to oxygen diffusion, determines the high oxygen permeability of skin in premature infants.

Forearm blood flow during body temperature transients produced by leg exercise

1975 ◽  
Vol 38 (1) ◽  
pp. 58-63 ◽  
Author(s):  
C. B. Wenger ◽  
M. F. Roberts ◽  
J. A. Stolwijk ◽  
E. R. Nadel
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Forearm Blood Flow ◽  
Bicycle Ergometer ◽  
Vapor Pressures ◽  
Internal Temperature ◽  
Ambient Temperatures ◽  
Forearm Skin ◽  
Leg Exercise ◽  
Skin Temperatures

Subjects exercised for 30 min on a bicycle ergometer at 30, 50, and 70% of maximal aerobic power in ambient temperatures of 15, 25, and 35 degrees C and vapor pressures of less than 18 Torr. Exercise was used to vary internal temperature during an experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Forearm skin temperature was fixed at about 36.5 degrees C. Esophageal temperature (Tes) was measured with a thermocouple at the level of the left atrium, and mean skin temperature (Tsk) was calculated from a weighted mean of thermocouple temperatures at eight skin sites. Forearm blood flow (BF) was measured by electrocapacitance plethysmography. Our data are well accounted for by an equation of the form BF = a1Tes + q2Tsk + b, independent of exercise intensity, although some subjects showed an equivocal vasodilator effect of exercise. The ratios a1/a2 (7.5, 9.6, 11.7) are quite similar to the ratios (8.6, 10.4) of the corresponding coefficients in two recent models of thermoregulatory sweating.

Prolactin Responses To Exercise In The Heat With Altered Skin Temperatures And Skin Blood Flow

2005 ◽  
Vol 37 (Supplement) ◽  
pp. S170
Author(s):  
David A. Low ◽  
N. Tim Cable ◽  
Alison Purvis ◽  
Thomas Reilly
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Skin Temperatures

Prolactin Responses To Exercise In The Heat With Altered Skin Temperatures And Skin Blood Flow

2005 ◽  
Vol 37 (Supplement) ◽  
pp. S170
Author(s):  
David A. Low ◽  
N. Tim Cable ◽  
Alison Purvis ◽  
Thomas Reilly
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Skin Temperatures

scholarly journals Skin blood flow in different ambient temperatures at rest and during exercise.

1985 ◽  
Vol 4 (1) ◽  
pp. 51-54
Author(s):  
Norihiro ISE ◽  
Tetsuo KATSUURA ◽  
Yoshiyuki KIKUCHI
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Ambient Temperatures

scholarly journals Effect of skin temperature on cutaneous vasodilator response to the β-adrenergic agonist isoproterenol

2015 ◽  
Vol 118 (7) ◽  
pp. 898-903 ◽  
Author(s):  
Gary J. Hodges ◽  
Dean L. Kellogg ◽  
John M. Johnson
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Skin Temperature ◽  
Skin Blood Flow ◽  
Local Skin ◽  
Vasodilator Response ◽  
Skin Cooling ◽  
Local Skin Temperature ◽  
Β Receptor ◽  
Skin Temperatures

The vascular response to local skin cooling is dependent in part on a cold-induced translocation of α2C-receptors and an increased α-adrenoreceptor function. To discover whether β-adrenergic function might contribute, we examined whether β-receptor sensitivity to the β-agonist isoproterenol was affected by local skin temperature. In seven healthy volunteers, skin blood flow was measured from the forearm by laser-Doppler flowmetry and blood pressure was measured by finger photoplethysmography. Data were expressed as cutaneous vascular conductance (CVC; laser-Doppler flux/mean arterial blood pressure). Pharmacological agents were administered via intradermal microdialysis. We prepared four skin sites: one site was maintained at a thermoneutral temperature of 34°C (32 ± 10%CVCmax) one site was heated to 39°C (38 ± 11%CVCmax); and two sites were cooled, one to 29°C (22 ± 7%CVCmax) and the other 24°C (16 ± 4%CVCmax). After 20 min at these temperatures to allow stabilization of skin blood flow, isoproterenol was perfused in concentrations of 10, 30, 100, and 300 μM. Each concentration was perfused for 15 min. Relative to the CVC responses to isoproterenol at the thermoneutral skin temperature (34°C) (+21 ± 10%max), low skin temperatures reduced (at 29°C) (+17 ± 6%max) or abolished (at 24°C) (+1 ± 5%max) the vasodilator response, and warm (39°C) skin temperatures enhanced the vasodilator response (+40 ± 9%max) to isoproterenol. These data indicate that β-adrenergic function was influenced by local skin temperature. This finding raises the possibility that a part of the vasoconstrictor response to direct skin cooling could include reduced background β-receptor mediated vasodilation.

Thermoregulatory control of finger blood flow

1975 ◽  
Vol 38 (6) ◽  
pp. 1078-1082 ◽  
Author(s):  
C. B. Wenger ◽  
M. F. Roberts ◽  
E. R. Nadel ◽  
J. A. Stolwijk
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Aerobic Power ◽  
Water Vapor Pressure ◽  
Bicycle Ergometer ◽  
Finger Blood Flow ◽  
Internal Temperature ◽  
Finger Temperature ◽  
Ambient Temperatures ◽  
Skin Temperatures

Three men exercised on a bicycle ergometer at 30, 50, asd 70 per cent of maximal aerobic power in ambient temperatures of 15, 25, and 35 degrees C with water vapor pressure less than 18 Torr. Exercies was used to vary internal temperature during as experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Finger temperature was fixed at about 35.7 degrees C. Espohageal temperature (Tes) was measured with a thermocouple at the level of the left atrium, and mean skin temperature (Tsk) was calcualted from a weighted mean of thermocouple temperatures at eight skin sites. Finger blood flow (BF) was measured by electrocapacitance plethysmography. Although some subjects showed small and equivocal vasomotor effects of exercise, our data are well accounted for by an equation of the form BF equal to alTes + a2Tsk + b, independent of exercise intensity. For these subjects, the ratios a1/a2 (5.9, 8.6, 9.4) were similar to the ratios of the corresponding coefficients recently reported for thermaoregulatory sweating (8.6, 10.4) and for forearm blood flow (9.6).

Attenuated thermoregulatory sweating and cutaneous vasodilation after 14-day bed rest in humans

2004 ◽  
Vol 96 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Daisaku Michikami ◽  
Atsunori Kamiya ◽  
Qi Fu ◽  
Satoshi Iwase ◽  
Tadaaki Mano ◽  
...  
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Sweat Rate ◽  
Bed Rest ◽  
Hot Water ◽  
Tympanic Temperature ◽  
Whole Body ◽  
Threshold Temperature ◽  
Cutaneous Vasodilation ◽  
Skin Temperatures

We investigated the effect of head-down bed rest (HDBR) for 14 days on thermoregulatory sweating and cutaneous vasodilation in humans. Fluid intake was ad libitum during HDBR. We induced whole body heating by increasing skin temperature for 1 h with a water-perfused blanket through which hot water (42°C) was circulated. The experimental room was air-conditioned (27°C, 30–40% relative humidity). We measured skin blood flow (chest and forearm), skin temperatures (chest, upper arm, forearm, thigh, and calf), and tympanic temperature. We also measured sweat rate by the ventilated capsule method in which the skin area for measurement was drained by dry air conditioned at 27°C under similar skin temperatures in both trials. We calculated cutaneous vascular conductance (CVC) from the ratio of skin blood flow to mean blood pressure. From tympanic temperature-sweat rate and -CVC relationships, we assessed the threshold temperature and sensitivity as the slope response of variables to a given change in tympanic temperature. HDBR increased the threshold temperature for sweating by 0.31°C at the chest and 0.32°C at the forearm, whereas it reduced sensitivity by 40% at the chest and 31% at the forearm. HDBR increased the threshold temperature for cutaneous vasodilation, whereas it decreased sensitivity. HDBR reduced plasma volume by 11%, whereas it did not change plasma osmolarity. The increase in the threshold temperature for sweating correlated with that for cutaneous vasodilation. In conclusion, HDBR attenuated thermoregulatory sweating and cutaneous vasodilation by increasing the threshold temperature and decreasing sensitivity. HDBR increased the threshold temperature for sweating and cutaneous vasodilation by similar magnitudes, whereas it decreased their sensitivity by different magnitudes.

scholarly journals Infrared thermography: usefulness in treatment with percutaneous needle electrolysis in cesarean section treatment. A case study

2019 ◽  
Vol 02 (02) ◽  
pp. 094-095
Author(s):  
Álvarez Prats D. ◽  
Carvajal Fernández O. ◽  
Jiménez Sánchez S.
Keyword(s):  
Blood Flow ◽  
Cesarean Section ◽  
Infrared Thermography ◽  
Skin Blood Flow ◽  
Scar Tissue ◽  
Surrounding Tissue ◽  
Time Interval ◽  
Imaging Tool ◽  
The Mean

Abstract Background and Aim In Spain, one out of every four births is a cesarean delivery and in most cases complications occur such as adhesions. Adhesions may cause functional problems, as well as psychological and esthetic problems, such as pain and itchiness.A correct scarring restores connections and replaces the lost tissue, preserving esthetics and functionality. The final change in tissue tone will be responsible for the correct reestablishment of the vascular network. If this does not occur correctly, we may encounter situations with a high level of hypervascularization (hypothermic areas) and the probability of generating fibrosis. Infrared thermography (IT) is a complementary imaging test which is able to capture the infrared radiation emitted by the human body and transform this information into a thermal image. There is proportionality between skin temperature and skin blood flow, therefore, the thermal images provide us with information on skin blood flow. These data are then used to identify the areas of hypervascularization or local inflammation. Aims The aim of this study was to evaluate whether scar tissue has a different temperature to the surrounding tissue, also to detect areas of hyperthermia (hipervascularization) and apply percutaneous needle electrolysis (PNE) using thermography as a tool for assessment and monitoring. Material and Methods A case study of a woman aged 34 years with two cesarean section scars, the last of which took place 6 months before.Four sessions of PNE were performed using IT as a method to identify treatment points, with a time interval of 21 days between each application. Via infrared thermography, the scar area was assessed and the points where a greater temperature was registered were marked. Subsequently, the PNE technique was applied, performing 3 impacts with a duration of 3 seconds and with an intensity of 4 mA in each point marked. The intervention procedure was performed under ultrasound guidance, based on a transverse section of the scar and positioning the needle on the long axis, at a 45° tilt from the skin. The Visual Analog Scale (VAS) was registered in the first and last session. Results After the performance of PNE on the hyperthermic points of the scar, the VAS decreased from 5 points to 0 and both the mean scar temperature in relation to the surrounding tissue improved, also, there was a reduction of the hyperthermic points. Conclusion Infrared thermography may be a complementary imaging tool for finding alterations in the mean temperature of a scar tissue and identifying hyperthermic points which are a therapeutic target in the treatment with PNE. Besides, it could become a follow-up tool to monitor the evolution of the temperature of the scar, and therefore the effectiveness of the treatment applied. Despite the results obtained in this case, further studies are required.

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