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Skin blood flow and sweating in health and disease. Craig Crandall, Ph.D. Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, and Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas. Semenza et al. Am J Prev Med 1999. - PowerPoint PPT Presentation
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Skin blood flow and sweating in health and disease
Craig Crandall, Ph.D.
Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas,
and
Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas.
Semenza et al. Am J Prev Med 1999
Semenza et al. N Engl J Med. 1996
Heat stress
Cutaneous vasodilation
Decreases systemic vascular
resistance
Increases cardiac output
Maintenance of blood pressure
Heart FailureBlood pressure = TPR * CO
Of the “excess” death identified in the cohort from the 1995 Chicago heat wave, 39% had a prior “heart condition”Semenza et al. N Engl J Med. 1996
Normothermia Heat stress
E.F. (%) 30 2 -
Age (yrs) 51 4 -
MAP (mmHg) 90 3 85 4
HR (bpm) 70 4 87 5*
Tsk ( C) 34.1 0.1 38.0 0.2*
Normothermia Heat stress
64 1 -
51 4 -
87 2 82 2
58 4 80 4*
34.1 0.1 38.0 0.2*
Heart Failure (N=14)NYHA Class II and III
Controls (N=14)
Cui, Arbab-Zadah, Prasad, Durand, Levine, Crandall. Circulation (2005)
Increase in core temperature (ºC)
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Sw
eat r
ate
(mg/
cm2 /
min
)
0.0
0.2
0.4
0.6
0.8
1.0
Cui, Arbab-Zadah, Prasad, Durand, Levine, Crandall Circulation (2005)
CutaneousVasculature
Central NervousSystem
Vasodilation
Vasoconstriction
Internal Temp
Skin Temp
SweatGland
Sudomotor
Congestive Heart Failure
Cui, Arbab-Zadah, Prasad, Durand, Levine, Crandall Circulation (in press)
Summary
Impaired thermoregulation in subjects with CHF is primarily due to reduced cutaneous vasodilation since sweating responses are normal during the heat stress.
Possible mechanisms ???
“We had a new recruit die here at ----------- last week due to a heat-induced
arrhythmia. His core temp was 106 F. He died standing in the chow line- and
had done very minimal exertion that day (2 mi walk several hours earlier). The
guy had burn injuries at age 11- he had skin grafts covering 30% of his trunk-
to include one axilla. Our Army medical fitness reg make no mention of skin
grafting/burns as a disqualifier- and we are seeking additional knowledge to
see if we need to change the regulation. Since so many of our soldiers have
recently acquired burn injuries and are subjected to tremendous thermal stress
we think that this is a very important question.”
Whole-body heat stress
Laser Scanner
SweatCapsule
Local Heater &Laser Probe Graft
Markings forScanner
Normotherm. Heat Stress
GraftGraft
0
1000
500
Sw
eat R
ate
(mg/
cm2 /
min
)
Control Graft
0.0
0.2
0.4
0.6
0.8
*
Normothermia Cold Stress Heat Stress
Cut
aneo
us V
ascu
lar
Con
duct
ance
(uni
ts/m
mH
g)
0.0
0.3
0.6
0.9
1.2
1.5
*
Grafted Skin
Normothermia Cold Stress Heat Stress
Cut
aneo
us V
ascu
lar
Con
duct
ance
(uni
ts/m
mH
g)
0.0
0.3
0.6
0.9
1.2
1.5
*
*Normal Skin
ACh Administration
SNP Administration Cutaneous
Vasculature
ACh Co-transmitters
EDHFNO VIP, etc.PGsEndothelium
Sympathetic Cholinergic Nerve
Dry Nitrogen Gas
Sweat Capsule Humidit
y Sensor
Laser Doppler Probe
Acetylcholine (ACh)(10-7 M to 1 M) Skin
10 mm
*
*
**
* P<0.05
Control EC50 = -3.34 ± 0.46 EC50 = -2.61 ± 0.44
P<0.01†
†
CV
C fr
om B
asel
ine
(au/
mm
Hg)
log [ACh]
-7 -6 -5 -4 -3 -2 -1-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
▼Graft
Cutaneous vascular conductance (CVC) response to exogenous acetylcholine (ACh)
log [SNP]
-8 -7 -6 -5 -4 -3 -2-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
Cutaneous vascular conductance (CVC) response to exogenous sodium nitroprusside (SNP)
Control
EC50 = -3.94 ± 0.45 EC50 = -4.43 ± 1.08▼ Graft *
* P<0.05
CV
C f
rom
Bas
elin
e (a
u/m
mH
g)
log [ACh]
-7 -6 -5 -4 -3 -2 -1-0.2
0.0
0.2
0.4
0.6
0.8
1.0 Control▼ Graft
SR
from
Bas
elin
e (m
g/cm
2 /m
in)
Sweat rate (SR) response to exogenous acetylcholine (ACh) administration
*
*
* P<0.05
• Cutaneous vasodilation to whole-body heating is absent in grafted skin
• ACh mediated vasodilation (endothelial dependent) is inhibited in grafted skin
• Nitric oxide mediated vasodilation (endothelial independent) is attenuated at the highest dose in grafted skin
• No sweating suggests abnormal or absence of functional sweat glands
Summary of Findings
• Juvenile (i.e. 6-9 months post-surgery) split thickness skin grafts have an attenuated capability of contributing to thermoregulation
• Increased risk of heat related injury
• It is unknown whether there is a restoration of cutaneous vasodilation and sweat function with graft maturity?
Implications
31 year old man with a 10 year history of drug abuse was found disoriented and combative. Blood pressure: 115/76 mmHg; heart rate: 197 bpm; respiratory rate: 72/min; temperature 107.2 F (41.8 C). Urine specimen tested positive for cocaine metabolite and negative for ethanol and other central nervous stimulants. Patient died. Human Pathology, 22:1141-1145, 1991.
38 year old known cocaine user was transported to emergency room by the police after acting bizarrely and barking like a dog. The patient was agitated, diaphoretic, incoherent, and unresponsive to pain. Urine specimen tested positive for cocaine and cocaine metabolites and nicotine. Blood pressure: 120/69 mmHg; heart rate: 150 bpm; respiration: 40/min; temperature 41.1 C (106 F). Patient died seven days after admission. Western J. Med. 150:210-212, 1989.
14 patients with rhabdomyolysis after cocaine use had an average temperature of 103.7 F (range 99 – 106 F). The average temperature for the 5 patients that died was 105.4 F (40.8 C). Acta Neurol. Scand. 92: 161-165, 1995.
Lidocaine Cocaine P-value
Blood pressure(mmHg)
85(3)
93(3)
0.001
Heart rate(bpm)
64(4)
74(5)
0.01
Esoph. Temp.(C)
36.75(0.08)
36.79(0.10)
0.2
CVC(% max)
9(2)
7(2)
0.09
Pre-heat stress (~30 min post-drug)
Mean ±(SEM)
Crandall, Vongpatanasin, Victor Ann Int Med 2002
(2 mg/kg) (2 mg/kg)
Crandall, Vongpatanasin, Victor Ann Int Med 2002
Crandall, Vongpatanasin, Victor Ann Int Med 2002
37.0 37.2 37.4 37.6 37.80.0
0.3
0.6
0.9
LidocaineCocaine
0
20
40
60
80
LidocaineCocaine
37.0 37.2 37.4 37.6 37.8Esophageal Temperature Esophageal Temperature
Cut
aneo
us V
ascu
lar
Con
duct
ance
Sw
eat R
ate
(mg/
cm2 /
min
)
4.0 Neutral
4.5
5.0 Warm
5.5
6.0 Hot
6.5
7.0 Very hot
7.5
8.0 Unbearably hot
Toner, Drolet, Pandolf Percept Motor Skills 1986
Crandall, Vongpatanasin, Victor Ann Int Med 2002
Summary
Intranasal cocaine significantly impairs thermoregulation as evidenced by a delay in the onset of cutaneous vasodilation and sweating. Moreover, cocaine impairs the perception of heating such that the individual does not recognize they are as hot when compared to the placebo trial.
Contributors
Scott Davis, Ph.D.David Keller, Ph.D.David Low, Ph.D.Marilee Brown, R.N.Rebecca MacDougal, M.D.Obiora Chukwumah, MBBSJohn Hunt, M.D.Gary Purdue, M.D.Karen Kowalske, M.D.
Normothermia Peak heat stress
Ski
n bl
ood
flow
(un
it)
0
20
40
60
80
100
120
140CHF Control
*
*
#