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Biomedical subjects

H Atherton

Publications and source records attributed to H Atherton.

7 recordsLinked to original sources
PubMed1998

Changes in skin blood flow over the foot with warming of the contralateral heel.

Vasospasm in one leg is a common complication of umbilical artery catheterization in preterm infants. It is a common practice to wrap the contralateral leg in a warm washcloth. The rationale for this intervention is to induce reflex vasodilatation of the affected extremity, thereby avoiding the necessity to remove or replace the catheter. This study tested the hypothesis that heating the contralateral extremity in preterm infants would increase peripheral blood flow to the contralateral foot. Ten stable preterm infants who had had no umbilical catheter inserted for at least 2 weeks were studied. Skin perfusion was measured using the laser Doppler method in the distal leg after heating of the opposite foot to 40.5 degrees C. Blood flow to the skin of the contralateral foot was measured before and after warming the ipsilateral one. The skin blood flow measured with and without heat application to the contralateral foot was not significantly different. Direct heat does not induce contralateral reflex vasodilatation in the foot of preterm infants.

Catheterization↗
PubMed1994

Measurement of transcutaneous carbon dioxide in low birthweight infants during the first two weeks of life.

With the advent of pulse oximetry, there has been a general decrease in the use of transcutaneous (Tc) blood gas monitoring in intensive care environments. The available data, however, suggest that arterial carbon dioxide pressure (PCO2) levels are best estimated by Tc methods. In this study, we report our experience using routine Tc PCO2 monitoring in 32 consecutive infants less than 2 weeks of age with birthweights less than 1500 g. A total of 644 simultaneous pairs (Tc PCO2 versus arterial PCO2) were obtained. Pairs were categorized according to a 2 x 2 matrix design based on sensor temperature (40 degrees or 43 degrees C) versus site of arterial sampling (umbilical [UAC] or peripheral artery catheter [PAC]). Sampling via the UAC resulted in excellent correlation between sample pairs at both sensor temperatures with similar regressions between groups. Sampling via the PAC, however, yielded poor correlation between sample pairs and a significantly different regression from both UAC groups. Based on these findings, we advocate the use of a sensor temperature of 40 degrees C in very low birthweight infants for tracking Tc PCO2 values. In addition, we suggest that inaccuracies in PAC sampling may lead to erroneous PCO2 determinations. We conclude that routine monitoring of Tc PCO2 is accurate and serves a useful and continuing role in the neonatal intensive care environment.

Arteries↗
PubMedDate not supplied

Effects of prior drug experience on the establishment of taste aversions in rats.

Groups of food and water deprived rats were injected with either 2 mg/kg d-amphetamine, 9mg/kg dl-fenfluramine or isotonic saline immediately after the first presentation of a 25 percent solution of condensed milk for a 30 min period. When animals were tested for aversion to condensed milk 8 days later both drugs were found to cause a highly significant decrease in total amounts drunk; in contrast saline injected animals showed significant increases in the amount drunk. However, it was found that the development of a conditioned taste aversion could be markedly attenuated or abolished altogether by providing groups of animals with experience of both drugs prior to aversion establishment, and that the degree of attenuation of aversion was proportional to the amount of prior experience. Novelty of drug administered would seem to be a critical variable in the establishment of taste aversions. The results are discussed with reference to some of the paradoxical aspects of drug induced taste aversions.

Animals↗