The effect of local heating on blood flow in the finger and the forearm skin

1987 ◽  
Vol 65 (6) ◽  
pp. 1329-1332 ◽  
Author(s):  
Tetsuo Nagasaka ◽  
Kozo Hirata ◽  
Tadahiro Nunomura ◽  
Michel Cabanac
Keyword(s):  
Blood Flow ◽  
Relative Humidity ◽  
Local Heating ◽  
Venous Occlusion ◽  
Water Bath ◽  
Strain Gauges ◽  
Forearm Skin ◽  
Thermal Sweating ◽  
Hot Environments ◽  
Male Subjects

Blood flow of the finger and the forearm were measured in five male subjects by venous occlusion plethysmography using mercury-in-Silastic strain gauges in either a cool–dry (COOL: 25 °C, 40% relative humidity), a hot–dry (WARM: 35 °C, 40% relative humidity), or a hot–wet (HOT: 35 °C, 80% relative humidity) environment. One hand or forearm was immersed in a water bath, the temperature (Tw) of which was raised every 10 min by steps of 2 °C until it reached 41° or 43 °C. While the other hand or forearm was kept immersed in a water bath (Tw, 35 °C), blood flow in the heated side (BFw) was compared with the corresponding blood flow in the control side (BFc). Under WARM or HOT conditions, linger BFw was significantly lower than finger BFc at a Tw of 39–41 °C in the majority of subjects. When Tw was raised to 43 °C, however, finger BFw became higher than BFc in nearly half of the subjects. In the COOL state, finger BFw did not decrease but increased steadily when Tw increased from 37° to 43 °C. In the forearm, BFw increased steadily with increasing Tw even in WARM–HOT environments. No such heat-induced vasoconstriction was observed in the forearm. From these results we conclude that in hyperthermic subjects, the rise in local temperature to above the core temperature produces vasoconstriction in the fingers, an area where no thermal sweating takes place.

Forearm skin and muscle vasoconstriction during lower body negative pressure

1986 ◽  
Vol 60 (5) ◽  
pp. 1535-1541 ◽  
Author(s):  
A. Tripathi ◽  
E. R. Nadel
Keyword(s):  
Blood Flow ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Venous Occlusion ◽  
Lower Body ◽  
Total Blood ◽  
Forearm Skin ◽  
The Difference ◽  
Total Blood Flow ◽  
Male Subjects

In view of conflicting reports of skeletal muscle and skin blood flow participation in baroreceptor-mediated reflexes, we studied the effects of graded lower body negative pressure (LBNP) on cutaneous and muscular components of forearm blood flow (FBF) in seven male subjects at 28 degrees C. FBF was measured by venous occlusion plethysmography and cutaneous flow by laser-Doppler velocimetry, the difference being the muscular flow. Mean FBF decreased by 39 and 56% from control at LBNP of 20 and 50 Torr, respectively. Skin flow decreased linearly with graded LBNP contributing 32% of the decrease of total blood flow at 20 Torr and then 50% of total decrease of blood flow at 50 Torr. Conversely, the decrease in muscle flow represented 68% of the total decrease at LBNP of 20 Torr and then 50% of the total decrease at LBNP of 50 Torr. We concluded that both skin and muscle circulations participate in sustained peripheral vasoconstriction during LBNP, with muscle flow achieving near maximum vasoconstriction by 20 Torr and skin showing a graded vasoconstriction to decreases in LBNP.

Effect of nerve block on response of forearm blood flow to local temperature

1986 ◽  
Vol 61 (1) ◽  
pp. 227-232 ◽  
Author(s):  
C. B. Wenger ◽  
L. A. Stephenson ◽  
M. A. Durkin
Keyword(s):  
Blood Flow ◽  
Nerve Block ◽  
Forearm Blood Flow ◽  
Brachial Plexus Block ◽  
Thermal Sensation ◽  
Strain Gauges ◽  
Forearm Skin ◽  
Plastic Bag ◽  
Plexus Block

To determine the role of neurotransmitter in the response of forearm blood flow (ABF) to local (forearm) skin temperature (Tsk) we measured ABF of six subjects at Tsk from 25 to 40 degrees C before (control) and after brachial plexus block (BPB). Control experiments were conducted in an ambient temperature of 27–29 degrees C, adjusted to minimize the subject's overall thermal sensation. Tsk was regulated by blowing a controlled-temperature airstream through a plastic bag enclosing the arm. We first lowered Tsk to 25 degrees C and after 20 min began to measure ABF with Whitney strain gauges. We then raised Tsk by 2.5 degrees C steps to 40 degrees C and measured ABF every 30 s for at least 10 min at each level of Tsk. Mean ABF rose from 1.1 ml X 100 ml-1 X min-1 at Tsk of 25 degrees C to 2.1 ml X 100 ml-1 X min-1 at 32.5 degrees C to 13.7 ml X 100 ml-1 X min-1 at 40 degrees C in control experiments and from 2.8 to 4.4 to 14.8 ml X 100 ml-1 X min-1 after BPB. The effect of Tsk on ABF was highly significant (P less than 0.0001) but the effect of BPB was not (P approximately equal to 0.2). At thermoneutrality, the effect of Tsk on ABF is largely independent of neural activity, since this effect is unaffected by nerve block.

scholarly journals β-Adrenergic blockade does not impair the skin blood flow sensitivity to local heating in burned and nonburned skin under neutral and hot environments in children

2017 ◽  
Vol 24 (4) ◽  
pp. e12350 ◽  
Author(s):  
Eric Rivas ◽  
Serina J. McEntire ◽  
David N. Herndon ◽  
Ronald P. Mlcak ◽  
Oscar E. Suman
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Adrenergic Blockade ◽  
Flow Sensitivity ◽  
Hot Environments

Cutaneous vascular response to exercise and acute hypoxia

1982 ◽  
Vol 53 (4) ◽  
pp. 920-924 ◽  
Author(s):  
L. B. Rowell ◽  
P. R. Freund ◽  
G. L. Brengelmann
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Acute Hypoxia ◽  
Venous Occlusion ◽  
Moderate Exercise ◽  
Work Intensity ◽  
Short Term ◽  
Forearm Skin ◽  
Response To Exercise ◽  
Cutaneous Vasoconstriction

Six normal young men were studied during 50 min of moderate exercise (100–137 W) that included one 15-min (protocol 1) or two 10-min periods of breathing 11–12% O2 (in N2) (protocol 2). Absolute work intensity was kept constant for each subject, but relative severity increased during hypoxia owing to reduction in maximum O2 uptake. Our question was whether hypoxia causes cutaneous vasoconstriction; this in turn should cause a rise in esophageal temperature (Tes) and a shift in the forearm skin blood flow (SkBF)-Tes relationship. In all subjects forearm blood flow (FBF) (venous occlusion plethysmography) rose throughout exercise and Tes tended to stabilize. Neither 10- nor 15-min periods of hypoxia caused systematic changes in FBF or Tes or their relationship to each other. We conclude that hypoxia equivalent to that incurred at 4,500–5,000 m does not significantly alter the short-term regulation of SkBF and body temperature during moderate exercise. Net cutaneous vasoconstriction is not elicited by arterial chemoreflexes under these conditions.

Maximal skin vascular conductance in subjects aged 5-85 yr

1995 ◽  
Vol 79 (1) ◽  
pp. 297-301 ◽  
Author(s):  
H. L. Martin ◽  
J. L. Loomis ◽  
W. L. Kenney
Keyword(s):  
Blood Flow ◽  
Reactive Hyperemia ◽  
Venous Occlusion ◽  
Activity Level ◽  
Vascular Conductance ◽  
Doppler Flowmetry ◽  
Resting Blood Pressure ◽  
Forearm Skin ◽  
Linear Fit ◽  
Minimal Resistance

This study examined maximal forearm skin vascular conductance (FVCmax) as a function of age in 74 healthy male and female subjects ranging in age from 5 to 85 yr. The skin temperature of the left forearm was uniformly clamped at 42 degrees C by spraying a fine mist of water over the surface. Forearm blood flow (FBF) was measured by venous occlusion plethysmography (Hg-in-Silastic strain gauge). After 60 min of heating, a reactive hyperemia maneuver was performed to verify that forearm skin blood flow was maximal by using laser Doppler flowmetry to isolate the skin component of FBF. The maximal FBF of each subject was then divided by mean arterial pressure to yield FVCmax (in ml.100 ml-1.min-1.100 mmHg-1), i.e., minimal resistance. The model that best fits the data was curvilinear, as described by FVCmax = 13.1 + 86.9 (age-0.75) (r2 = 0.52, P < 0.001). The exclusion of subjects younger than 18 yr of age simplified the model to a linear fit with a slope of -0.16 conductance units/yr for adults. Interindividual variability remained constant across the entire age span. Once the age effect was considered, there were no significant effects of gender, adiposity, resting blood pressure, physical activity level, or body surface area on FVCmax.

Chronic hormone replacement therapy does not alter resting or maximal skin blood flow

1998 ◽  
Vol 85 (2) ◽  
pp. 505-510 ◽  
Author(s):  
E. M. Brooks-Asplund ◽  
W. L. Kenney
Keyword(s):  
Blood Flow ◽  
Replacement Therapy ◽  
Postmenopausal Women ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Hormone Replacement ◽  
Venous Occlusion ◽  
Body Core Temperature ◽  
Vascular Conductance ◽  
Doppler Flowmetry

Postmenopausal women on estrogen replacement therapy (ERT) regulate body core temperature at a lower baseline level at rest in a thermoneutral environment. We conducted a series of studies to test whether, in a thermoneutral environment, chronic (≥2 yr) oral ERT significantly alters baseline skin blood flow (SkBF) and cutaneous vascular conductance (CVC) and whether ERT alters maximal CVC (CVCmax) and SkBF in postmenopausal women. In the first set of studies, forearm blood flow (FBF) was measured by venous-occlusion plethysmography in 24 postmenopausal women: 8 not taking exogenous hormone therapy (No HRT group), 8 on ERT, and 8 receiving combination of estrogen and progesterone therapy, at rest and during prolonged (1 h) local heating of the forearm at 42°C. Mean arterial pressure (MAP) was measured by brachial auscultation before each set of FBF measurements to calculate forearm vascular conductance (FVC = FBF/MAP). SkBF was measured by laser-Doppler flowmetry (LDF), and CVC was calculated as LDF/MAP and standardized as %CVCmax. Baseline FVC, %CVCmax, and maximal FVC were not significantly different among the three groups of women. In the second set of experiments, LDF in ERT and No HRT groups was measured at rest in both thermoneutral and warm environments. %CVCmax was again not significantly different between ERT and No HRT groups at thermoneutral ambient temperatures and increased similarly in the warm environment. Therefore, chronic exogenous ERT does not appear to influence either baseline or maximal SkBF.

Control of skin blood flow during exercise by thermal reflexes and baroreflexes

1980 ◽  
Vol 48 (4) ◽  
pp. 717-723 ◽  
Author(s):  
M. F. Roberts ◽  
C. B. Wenger
Keyword(s):  
Blood Flow ◽  
Stroke Volume ◽  
Skin Temperature ◽  
Forearm Blood Flow ◽  
Weighted Average ◽  
Venous Occlusion ◽  
Air Temperatures ◽  
Cycle Ergometers ◽  
Cardiac Filling ◽  
Male Subjects

Four male subjects exercised on cycle ergometers at 40-51% of maximal aerobic power in the upright and supine positions at air temperatures of 15, 25, and 40 degrees C. Esophageal temperature (Tes) was measured at heart level, and mean skin temperature was computed from a weighted average of eight skin temperature measurements. Forearm blood flow (ABF) was measured by venous occlusion plethysmography, and cardiac output was measured by a CO2 rebreathing technique. At air temperatures of 15 and 25 degrees C, cardiac stroke volume was slightly lower during upright exercise than it was during supine exercise, as was ABF at a given Tes. At 40 degrees C, however, stroke volume was much lower and ABF at a given Tes was considerably lower during upright as opposed to supine exercise. The reduced stroke volume during upright exercise in the heat shows that gravity compounds the effect of cutaneous venodilation by allowing blood to pool in dependent limbs and thus impairing cardiac filling. The proportionality between reduced stroke volume and reduced forearm blood flow suggests that the reduction in blood flow may be mediated by cardiopulmonary baroreflexes that are activated by reduced cardiac filling pressure.

scholarly journals Cutaneous Vascular Responses to Acetylcholine are Mediated by a Prostanoid-Dependent Mechanism in Man

1997 ◽  
Vol 2 (2) ◽  
pp. 82-86 ◽  
Author(s):  
Faisel Khan ◽  
Neil C Davidson ◽  
Roberta C Littleford ◽  
Stuart J Litchfield ◽  
Allan D Struthers ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Relative Proportion ◽  
Venous Occlusion ◽  
Normal Male ◽  
Doppler Flowmetry ◽  
Vascular Responses ◽  
Before And After ◽  
Forearm Skin ◽  
Dependent Mechanism

Approximately 50% of the forearm vasodilatation to intra-arterial infusions of acetylcholine is mediated by endothelium-derived nitric oxide. These conclusions have been derived from venous occlusion plethysmographic measurements of total forearm blood flow during co-infusions of acetylcholine and Ng-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide synthase. Since venous occlusion plethysmography measures total limb blood flow, the relative proportion of the measurement from skin cannot be determined precisely. To determine the effects of acetylcholine on skin specifically, we have used laser Doppler flowmetry to measure vascular responses to local iontophoresis of acetylcholine in the forearm of normal male volunteers. To elucidate the possible mechanisms of cutaneous vasodilatation to acetylcholine, vascular responses were measured before and after systemic inhibition of prostanoid production and nitric oxide synthesis by oral aspirin (600 mg daily for 3 days) and intravenous L-NMMA (3 mg/kg for 60 min), respectively. After aspirin administration, dose-dependent vascular responses to acetylcholine were reduced significantly by approximately 53% (p<0.005, ANOVA). In contrast, intravenous L-NMMA appeared to have no significant effect on cutaneous vascular responses to acetylcholine. While the role of nitric oxide is uncertain, vasodilatation to acetylcholine in the forearm skin is mediated largely by a prostanoid-dependent mechanism. Assessment of cutaneous vascular responses to iontophoresis of acetylcholine may, therefore, be useful in diseases where abnormal endothelium-dependent prostanoid function has been implicated.

Effect of CO2 and 100% O2 on cerebral blood flow in preterm infants

1980 ◽  
Vol 48 (3) ◽  
pp. 468-472 ◽  
Author(s):  
F. A. Leahy ◽  
D. Cates ◽  
M. MacCallum ◽  
H. Rigatto
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Preterm Infants ◽  
Cerebral Circulation ◽  
Pressure Change ◽  
Venous Occlusion ◽  
Co2 Sensitivity ◽  
Important Regulator ◽  
Carbon Dioxide Pressure

To determine 1) the effect of arterial CO2 change on the neonatal cerebral circulation and 2) whether 100% O2 would produce significant decrease in cerebral blood flow (CBF), we studied 24 preterm infants to explain the late (5 min) hyperventilation observed in them during hyperoxia. Of these, 12 were studied before and during inhalation of 2-3% CO2 and 12 before and during the inhalation of 100% O2. We measured CBF by a modification of the venous occlusion plethysmography technique and found that CBF increased 7.8% per Torr alveolar carbon dioxide pressure change and that it decreased 15% with 100% O2. These findings suggest that 1) CO2 is an important regulator of CBF in the perterm infant, 2) CBF-CO2 sensitivity in these infants may be greater than in adult subjects, 3) 100% O2 reduced CBF significantly, and 4) a decrease in CBF during administration of 100% O2 may be at least partially responsible for the increase in ventilation with hyperoxia.

scholarly journals Combined heat and mental stress alters neurovascular control in humans

2010 ◽  
Vol 109 (6) ◽  
pp. 1880-1886 ◽  
Author(s):  
Jenna C. Klein ◽  
Craig G. Crandall ◽  
R. Matthew Brothers ◽  
Jason R. Carter
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Mental Stress ◽  
Muscle Sympathetic Nerve Activity ◽  
Thermal Conditions ◽  
Venous Occlusion ◽  
Vascular Conductance ◽  
Vascular Responses ◽  
Time Condition ◽  
Forearm Skin

This study examined the effect of combined heat and mental stress on neurovascular control. We hypothesized that muscle sympathetic nerve activity (MSNA) and forearm vascular responses to mental stress would be augmented during heat stress. Thirteen subjects performed 5 min of mental stress during normothermia (Tcore; 37 ± 0°C) and heat stress (38 ± 0°C). Heart rate, mean arterial pressure (MAP), MSNA, forearm vascular conductance (FVC; venous occlusion plethysmography), and forearm skin vascular conductance (SkVCf; via laser-Doppler) were analyzed. Heat stress increased heart rate, MSNA, SkVCf, and FVC at rest but did not change MAP. Mental stress increased MSNA and MAP during both thermal conditions; however, the increase in MAP during heat stress was blunted, whereas the increase in MSNA was accentuated, compared with normothermia (time × condition; P < 0.05 for both). Mental stress decreased SkVCf during heat stress but not during normothermia (time × condition, P < 0.01). Mental stress elicited similar increases in heart rate and FVC during both conditions. In one subject combined heat and mental stress induced presyncope coupled with atypical blood pressure and cutaneous vascular responses. In conclusion, these findings indicate that mental stress elicits a blunted increase of MAP during heat stress, despite greater increases in total MSNA and cutaneous vasoconstriction. The neurovascular responses to combined heat and mental stress may be clinically relevant to individuals frequently exposed to mentally demanding tasks in hyperthermic environmental conditions (i.e., soldiers, firefighters, and athletes).

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