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Biomedical subjects

D M Kerslake

Publications and source records attributed to D M Kerslake.

12 recordsLinked to original sources
PubMed1991

The insulation provided by infants' bedclothes.

The insulation provided by bedclothes of given thermal resistance (tog value) depends on the size of the body insulated. For simple shapes, discs, strips and cylinders, it is always less than the tog value. If the trunk and limbs of a baby are considered to be thermally independent cylinders, each with the bedclothes well tucked in, the net insulation, I, in tog units, is described by (1/I) = 0.6/Ib + 0.3/Im + 4.5/G, where Ib is the tog value of the bedclothes, Im that of the mattress and G the girth of the trunk in centimetres. I is reduced if the cot is small, if occupation has been belief, and if the bedclothes are loosely draped over the baby. I is increased (perhaps 2.5 times) if the baby curls up tightly. It is concluded that there is little risk of overinsulating a normal baby whose posture is not restricted, but a combination of fever and thick bedclothes might be dangerous.

Bedding and Linens↗
PubMed1979

An estimation of intracranial blood flow in the new-born infant.

1. A non-invasive method for the estimation of the intracranial blood flow of the new-born infant is described, and results obtained with it are presented. 2. The technique is a novel application of the principle of blood flow measurement by venous occlusion plethysmography. It is possible to apply a plethysmographic technique to the neonatal cranium because the presence of open sutures between the component bones permits small, but readily measurable, changes in intracranial volume to occur. 3. Skull volume changes are calculated from changes in the occipito-frontal circumference of the cranium as recorded and measured with a mercury-in-Silastic strain gauge. 4. The jugular veins in the baby's neck are occluded by finger pressure and there follows an increase in skull volume, which is rapid at first, but which decreases exponentially as venous drainage diverts to non-occluded channels such as the vertebral venous plexus. At the instant of jugular occlusion the rate of skull volume increase is representative of the rate of flow in the jugular vessels prior to occlusion, and so provides an index of the relative magnitude of the intracranial blood flow. The method thus allows changes in intracranial blood flow to be followed. When occlusion is released cranial volume decreases, initially rapidly, but slowing exponentially as resting volume is regained. 5. A theoretical model of the events occurring during the inflow and outflow phases has been developed, and a formula derived which allows an estimation to be made of the flow of blood through uncompressed channels. The measured value of jugular blood flow can then be augmented to an estimate of total intracranial flow. 6. The mean cerebral blood flow of sixteen normal babies was estimated to be 40 ml. 100 g-1.min-1 (S.D. = +/- 11.63).

Brain↗
PubMed1969

The relation between sweat rate and weight loss when sweat is dripping off the body.

1. The relation between the rate of sweat production, S, and the rate of weight loss, W, has been examined under conditions in which the rate of evaporation was small.2. S could be found from W provided that a film of liquid was maintained over the skin surface. This could be achieved initially by immersing the subject in water containing detergent. Thereafter the film was maintained so long as the rate of weight loss exceeded about 10 g/min.3. When the rate of weight loss was changing and the rate of evaporation was constant, S could be calculated as W + 2.5 W.4. When the subject was constantly sprayed with water while being weighed, the correction for W became negligible. In this case there was no lower limit to the sweat rate which could be measured, but spraying considerably reduced the accuracy of the measurement.5. The output of sweat from a ventilated capsule on the forearm correlated well with estimates of central sweating drive based on weight measurements corrected for hidromeiosis.

Body Weight↗
PubMed1968

The effects of soaking the skin in water at various temperatures on the subsequent ability to sweat.

1. The ability of two human subjects to produce sweat was measured before and after immersion for up to 4 hr in water at 32-36 degrees C (soak).2. The ability to produce sweat declined about 4 times as rapidly when the subject was soaked at 36 degrees C as at 32 degrees C.3. The rate of decline characteristic of soaking at 36 degrees C was shown by subjects exercising in water at 35 degrees C, but not at rest at 35 degrees C. The difference appeared to be related to the presence or absence of moderate sweating (300 g/hr) during the soak. At higher rates there was no further increase in the rate of decline.4. Soaking at 39 degrees C for 5 min, after which the water temperature was reduced to 33 degrees C, caused a decline consistent with the supposition that while the subject was sweating the rate of decline was the same as that at 36 degrees C and for the rest of the time the same as that at 32 degrees C.5. It is concluded that the rate of decline is increased if the sweat ducts are perfused, and some possible mechanisms are discussed.

Body Weight↗