Skin blood flow changes during apneic spells in preterm infants

Changes in skin blood flow during apneic spells were determined in 18 preterm infants using a diode laser Doppler flow meter without light conducting fibres. Heart rate, nasal air flow, impedance pneumography, skin and incubator temperature and laser Doppler skin blood flow were recorded simultaneously in each infant. During 212 apneic spells with a duration of 11.6 ± 7.5 s (mean ± S.D.) (range 6.0–48.0 s), the laser Doppler skin blood flow was measured. In all children except one, the majority of the apneic spells was associated with a decrease in skin blood flow. During 155 apneic spells (73%) skin blood flow decreased significantly P < 0.025), the maximum decrease being 16.7 ± 14.8%, 28.5 ± 23.9% and 18.9 ± 16.1% (mean ± S.D.) for central, obstructive and mixed apneic spells, respectively. The decrease in skin blood flow started immediately after the beginning of apneic spells in 71%, the rest started with a mean delay of 3.4 s (range 0.1–7.0 s). No relation was found between the decrease in skin blood flow and the duration of the apneic spells. Thirty-four percent of the apneic spells were accompanied by bradycardia. In apneic spells accompanied by bradycardia the decrease in skin blood flow was not related to the fall in heart rate

Forehead Skin Blood Flow in Normal Neonates during Active and Quiet Sleep, Measured with a Diode Laser Doppler Instrument

Changes in forehead skin blood flow during active and quiet sleep were determined in 16 healthy neonates using a recently developed semi-conductor laser Doppler flow meter without light conducting fibres. Measurements were carried out at a postnatal age varying from 5 hours to 7 days. The two sleep states could be distinguished in 17 recordings. The mean skin blood flow values during active sleep were significantly higher (p<0.01) than those during quiet sleep, the mean increase being 28.1%. The variability of the flow signal, expressed as the coefficient of variation, changed significantly from 23.1% during active sleep to 18.2% during quiet sleep

Influence of local anesthetics on tissue blood flow−The change of skin blood flow by subcutaneous injection into the back skin of rabbits−

We examined the influence of lidocaine, mepivacaine, ropivacaine , bupivacaine , and levobupivacaine on skin blood flow in rabbits using a laser Doppler blood flowmeter. New Zealand White rabbits were anesthetized with sodium thiopental. 0.2 ml of 0.125～ 2.0% lidocaine, 0.125～3.0% mepivacaine, 0.125～0.75% ropivacaine, 0.125～0.5% bupivacaine, 0.125～0.75% levobupivacaine, 2.0% lidocaine with adrenaline (A) (1/80,000), and 3.0% propitocaine with felypressin (0.03 IU) were injected subcutaneously into the back skin of the rabbit’s. Physiological saline (0.2 ml) was injected as a control. We measured the skin blood flow using a laser Doppler blood flowmeter before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, and 10 minutes after the injection. The blood flow after the injection of each local anesthetic was converted into a percentage of the control value (before injection). The mean values of the skin blood flow before the injection in each group showed no significant differences. The skin blood flow was increased 30 seconds after the injection of physiological saline and showed no significant changes from 1 to 10 minutes after the injection. The skin blood flow was significantly increased by the subcutaneous injection of 0.125, 0.25, 0.5, 0.75, 1.0, and 2.0% lidocaine, 1.0, 2.0, and 3.0% mepivacaine, 0.125, 0.25, and 0.5% bupivacaine, and 0.75% levobupivacaine. The skin blood flow was significantly decreased by the injection of 0.125, 0.25, 0.5, and 0.75% mepivacaine, 0.125, 0.25, 0.5, and 0.75% ropivacaine, 0.125, 0.25, and 0.5% levobupivacaine. Lidocaine and bupivacaine increased the skin blood flow dependent on their concentration. On the other hand, ropivacaine decreased the skin blood flow dependent on its concentration. Mepivacaine decreased the skin blood flow at concentrations lower than 0.75% and increased it at a concentration higher than 1.0%. Levobupivacaine decreased the skin blood flow at concentrations lower than 0.5%, and increased it at those higher than 0.75%. The 0.5% bupivacaine and 2.0% lidocaine led to the most marked increase in skin blood flow, and 2.0% lidocaine?A and 0.75% ropivacaine led to the most marked decrease.2013博士（歯学）松本歯科大

Basic Taste Stimuli Elicit Unique Responses in Facial Skin Blood Flow

Facial expression changes characteristically with the emotions induced by basic tastes in humans. We tested the hypothesis that the five basic tastes also elicit unique responses in facial skin blood flow. Facial skin blood flow was measured using laser speckle flowgraphy in 16 healthy subjects before and during the application of basic taste stimuli in the oral cavity for 20 s. The skin blood flow in the eyelid increased in response to sweet and umami taste stimuli, while that in the nose decreased in response to a bitter stimulus. There was a significant correlation between the subjective hedonic scores accompanying these taste stimuli and the above changes in skin blood flow. These results demonstrate that sweet, umami, and bitter tastes induce unique changes in facial skin blood flow that reflect subjective hedonic scores

Distinct Effects of Blood Flow and Temperature on Cutaneous Microvascular Adaptation

Aims: We performed two experiments to determine whether cutaneous microvascular adaptations in response to repeated core temperature elevation are mediated by increases in skin temperature, and/or, skin blood flow. Methods: Healthy subjects participated for 8-weeks in thrice-weekly bouts of 30mins lower limb heating (40°C). In Study 1, both forearms were “clamped” at basal skin temperature throughout each heating bout (n=9). Study 2 involved identical lower limb heating, with the forearms under ambient conditions (unclamped, n=10). In both studies, a cuff was inflated around one forearm during the heating bouts to assess the contribution of skin blood flow and temperature responses. We assessed forearm skin blood flow responses to both lower limb (systemic reflex) heating, and to local heating of the forearm skin, pre and post intervention. Results: Acutely, lower limb heating increased core temperature (Study 1: +0.63±0.15°C, Study 2: +0.69±0.19°C, P<0.001) and forearm skin blood flow (Study 1: 10±3 vs 125±44, Study 2: 16±9 vs 136±41 PU, P<0.001), with skin responses significantly attenuated in the cuffed forearm (P<0.01). Skin blood flow responses to local heating decreased in Study 1 (clamped forearms, week 0vs8: 1.46±0.52 vs 0.99±0.44 CVC, P<0.05), whereas increases occurred in Study 2 (unclamped; week 0vs8: 1.89±0.57 vs 2.27±0.52 CVC, P<0.05). Cuff placement abolished local adaptations in both studies. Conclusion: Our results indicate that repeated increases in skin blood flow and skin temperature result in increased skin flux responses to local heating, whereas repeated increases in skin blood flow in the absence of change in skin temperature induced the opposite response. Repeated increases in core temperature induce intrinsic microvascular changes, the nature of which are dependent upon both skin blood flow and skin temperature

Effect Of Fluocinolone Acetonide Cream On Human Skin Blood Flow

Blood flow rate was measured in the forearm skin of human subjects exposed to ultraviolet irradiation. Blood flow was determined by the 133Xe disappearance technique 18hr after ultraviolet (UV) irradiation with a Westinghouse RS sunlamp held 10 inches from the skin for 10min. Ultraviolet irradiation caused skin blood flow to increase. Application of fluocinolone acetonide cream, 0.025%, 4 times in the 16hr following UV irradiation had no effect on either control skin blood flow or the UV-induced hyperemia

Primary Aging: Thermoregulatory Sweating & Skin Blood Flow

Heat related morbidities and mortalities are disproportionately high in the aged population(=60 yr). Aging without overt illness is associated with the attenuation of heat dissipationmechanisms including cutaneous vasodilation and eccrine sweating responses. These agerelateddecrements in thermoregulatory function are well represented in literature discussingheat dissipation, yet despite attempts to investigate a potential signaling mechanismbetween sweating and skin blood flow (SkBF), a functional link has not beendemonstrated. Recent evidence supports a role of nitric oxide (NO), a potent signalingmolecule in cutaneous vasodilation, as additionally signaling the eccrine sweatingresponse. The aim of this study was to investigate the putative role of NO in eccrine sweatgland signaling in young and primary aged individuals. Prior to experimentation, pilotstudies were conducted to develop experimental drug dilutions to achieve a successful flowmatching protocol. In two subjects, three intradermal microdialysis (MD) probes wereinserted into the left ventral forearm and perfused with 1) Lactated Ringer’s solution, 2)Epoprostenol sodium (EPO) + NG-Nitro-L-arginine (L-NNA), and 3) Sodium Nitroprusside(SNP) + L-NNA. Regional sweating rates (RSR) over each MD membrane were measuredusing ventilated capsules with a laser Doppler probe housed in each capsule formeasurement of red cell flux (laser Doppler flux, LDF) and divided by mean arterial bloodpressure (Cutaneous vascular conductance (CVC) = LDF/MAP) as an index ofSkBF. Subjects completed a whole body heating protocol to a 1°C rise in sublingualtemperature. Maximal CVC values were obtained pharmacologically at the end of eachprotocols using 25 mM SNP. During whole body heating in the second pilot, the L-NNA/EPOsite displayed lower levels of CVC than the control site, implying the EPO had becomeinactive. A buffer solution was created to maintain EPO stability at physiological pH. Thenext steps are to complete pilot tests with EPO in buffer to ensure it remains active and toachieve a successful flow matching protocol before beginning the sweating study