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Biomedical subjects

J K Stothers

Publications and source records attributed to J K Stothers.

13 recordsLinked to original sources
PubMed1979

Hats for the newborn infant.

The efficacy of a Gamgee-lined hat in reducing the rate of fall in rectal temperature of infants during the first 30 minutes of life was studied. The trial, which included 211 infants, was randomised, prospective, and controlled. One hundred and seven infants were exposed to overhead radiantheaters. Of these, only 30 had normal deliveries, so the analysis was confined to the infants who were not subjected to radiant heat, and in this group no conclusions were drawn about the efficacy of a hat or a radiant heater. In the 104 infants not subjected to radiant heat, body weight, initial rectal temperature, the application of hat, the environmental temperature, and the duration of exposure while naked were all found to influence measureably the rate of fall in rectal temperature during the first 30 minutes. Gamgee-lined hats should be routinely used to minimise heat loss, especially in small infants exposed at birth, during surgical operations, and during investigations necessitating prolonged exposure.

Body Temperature↗
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↗
PubMed1979

Effect of feeding on neonatal oxygen consumption.

Oxygen consumption was measured in 9 short-gestation infants before feeding and for an hour after, using a closed-circuit metabolism chamber. Using the same system, O2 consumption of 9 term infants was measured for varying periods, beginning one hour from the end of the last feed. In the short-gestation infants a rise was found in the 15--45 minutes after feeding; O2 consumption then fell, and after 60 minutes had reached prefeed levels. The term infants showed no decrease with time after the first hour, as would be expected if the effect of feeding on O2 consumption extended beyond this. It is concluded that increased O2 demand after appropriate feeding does not extend beyond one hour postprandially.

Eating↗
PubMed1978

Oxygen consumption and neonatal sleep states.

1. In thirty full-term infants in the first week of life, nursed in a constant volume, closed-circuit metabolism chamber in a neutral thermal environment (31.5-33.5 degrees C), measurements were made of oxygen consumption ( V(O2)) during periods of rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep.2. The mean V(O2) during REM sleep was 5.97 ml. kg(-1). min(-1). In NREM sleep the mean V(O2) was 5.72 ml. kg(-1). min(-1). This difference was significant (paired t test P < 0.05).3. When the direction of sleep state change was taken into account the difference in V(O2) between the two states was much less when REM sleep preceded NREM than when the change was in the opposite direction. In nineteen infants in whom the change was from REM to NREM the difference in V(O2) (6.18 and 6.03 ml. kg(-1). min(-1)) was not significant (P > 0.05). The mean difference when the sleep state change was from NREM to REM was significant (P < 0.01), the values being 5.54 and 5.81 ml. kg(-1). min(-1) respectively.4. In the NREM state, a gradual diminution of V(O2) with time was consistently found. This was not the case in REM sleep.5. In twelve infants studied in a cool environment (29 +/- 0.5 degrees C) V(O2) during REM sleep was 7.77, and during NREM sleep it was 6.58 ml. kg(-1). min(-1), (P < 0.001). Thus even the maximum difference found in a neutral thermal environment of 6.6% was significantly increased to 14.9% (P < 0.01) with mild thermal stress.6. No consistent changes in V(O2) with time were found in either REM or NREM sleep in twelve infants studied in a cool environment, in contrast to the findings in thermal neutrality

Humans↗
PubMed1975

Relation between changes in plasma calcium in first week of life and renal function.

(1) Of 71 infants fed on reconstituted dried or evaporated cow's milk, 31 showed a fall in plasma calcium between the 1st and 6th days of life, whereas in 35 breast-fed infants this occurred in only 5. (2) Those artificially-fed infants who had shown a rise in plasma calcium over this period had significantly lower plasma creatinine values and significantly higher excretion of creatinine than those infants who showed a fall in calcium levels. (3) Artificially-fed infants who had shown a rise in calcium had significantly lower plasma osmolality and significantly higher osmolar excretion in the urine than those infants who showed a fall in plasma calcium. (4) It is suggested that a delay in the normal increase in glomerular filtration rate during the first week of life in some infants leads to phosphate retention. This, together with a higher dietary intake of phosphate, leads to a decrease of the plasma calcium to hypocalcaemic levels.

Animals↗