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Biomedical subjects

H E Suichies

Publications and source records attributed to H E Suichies.

6 recordsLinked to original sources
PubMed1992

Digital blood flow in cooled and contralateral finger in patients with Raynaud's phenomenon. Comparative measurements between photoelectrical plethysmography and laser Doppler flowmetry.

The effects of cooling of a hand on lateral and contralateral digital skin blood flow were investigated in 18 patients with primary or secondary Raynaud's phenomenon. The aim of the study was to compare photoelectrical plethsmography (PhEP) and laser Doppler flowmetry (LDF). PhEP and LDF were used simultaneously for skin blood flow measurements of the third finger of both hands. One hand was cooled in water from 33 degrees to 3 degrees C in steps of 3 degrees C, each step lasting four minutes. It was followed by a recovery period of ten minutes in room air of 24 degrees C. During stepwise cooling from 33 degrees to 9 degrees C the relative PhEP and LDF values, measured on the cooled hand, decreased to 6.2% +/- 3.2% and 10% +/- 12% respectively. The correlation coefficients between LDF and PhEP varied between 0.79 and 0.99. In the contralateral hand the relative PhEP and LDF values decreased to 38% +/- 30.% and 64% +/- 7.9% respectively. The correlation coefficients between LDF and PhEP values were lower on the contralateral hand and ranged from 0.26 to 0.95. By calculating the LDF/PhEP ratios during cooling and recovery, more specific changes in red blood cell velocities during cooling were studied. Increasing LDF/PhEP ratios suggest increasing red blood cell velocities during cooling at 9 degrees C and a difference in the measuring methods. For testing the severity of Raynaud's phenomenon and the effect of treatment the results of both methods show consistent and quite comparable results when measured on the cooled hand. The effect of indirect cooling on the contralateral hand is, however, less consistent.

Adult↗
PubMed1990

Skin blood flow changes, measured by laser Doppler flowmetry, in the first week after birth.

Changes in forehead skin blood flow were determined in 17 healthy, term newborns, using a fiberless diode laser Doppler flow meter (Diodopp). Measurements were carried out three times on each infant, at postnatal ages of 16.8 +/- 7.4 h, 58.9 +/- 6.2 h and 121.5 +/- 14.2 h (mean +/- S.D.), respectively. Skin blood flow, respiration, heart rate and skin temperature were recorded simultaneously, while the newborns were asleep. During the recordings, the behavioural state of the newborns was observed and environmental temperature and humidity were kept constant. Postocclusive hyperaemia of the skin blood flow was obtained by pressing the laser Doppler probe against the skull for 30 or 60 s. The following parameters changed significantly between the first and third measurements (t-test for paired samples): the basal skin blood flow during active and quiet sleep decreased, the average decrease being 29.4% (P = 0.002) and 25.9% (P = 0.01), respectively; skin blood flow during postocclusive hyperaemia also changed: the time taken to reach maximum hyperaemia increased from 17.3 to 22.7 s (P = 0.01), while the halftime recovery increased from 46.1 to 57.1 s (P = 0.02). The changes in skin blood flow between the first and second measurements and between the second and third measurements did not reach the level of statistical significance.

Blood Flow Velocity↗
PubMed1989

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 less than 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.

Blood Flow Velocity↗
PubMed1989

Postocclusive reactive hyperaemia of cutaneous blood flow in premature newborn infants.

Reactive hyperaemia, which occurs after a period of arterial occlusion is the result of an autoregulatory mechanism, involving local factors and autonomic nerve system control. To determine this autoregulatory mechanism in cutaneous blood flow in premature newborns measured the cutaneous reactive hyperaemia response after a 1 min occlusion, using a diode laser Doppler flowmeter applied to the skin. Twenty-four infants with a gestational age ranging from 25 to 37 weeks and a postnatal age of 0.3 to 72 days were studied. The reactive hyperaemia response is described by the parameters maximal cutaneous blood flow (Vmax), the time to reach maximal flow (tmax), the time taken for blood flow to return to baseline following Vmax (t(end)) and the % increase in cutaneous blood flow above preocclusional level (overshoot). A cutaneous reactive hyperaemia response could be elicited in all infants. Following occlusion the Vmax was 2,640 +/- 1,050 mV (mean +/- SD), the tmax was 7.6 +/- 3.9 sec (mean +/- SD), the t(end) was 35.6 +/- 14.6 sec (mean +/- SD) and the overshoot was 74.6 +/- 34% (mean +/- SD). A negative correlation was found between hematocrit and tmax (r = -0.62, p less than 0.01). No influence of postconceptional age, postnatal age, skin and rectal temperature, incubator temperature, weight, and transcutaneous oxygen tension on the reactive hyperaemia parameters could be found. We conclude that reactive hyperaemia of cutaneous blood flow can be elicited in premature newborn infants irrespective of postconceptional age, and that the hematocrit is inversely related to the time to reach maximal flow after occlusion.

Age Factors↗
PubMed1988

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 with-out 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 less than 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.

Forehead↗