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Biomedical subjects

K R Hughes

Publications and source records attributed to K R Hughes.

17 recordsLinked to original sources

An argument for orogastric tubes during caesarean section.

Routine orogastric aspiration of stomach contents during general anaesthesia for caesarean section was recommended in the latest triennial report on maternal deaths. We conducted a postal survey which revealed that the majority of obstetric units do not follow this guideline. Following the report, we aspirated the stomach contents of all our patients undergoing general anaesthesia for caesarean section and analysed the aspirate volume and pH. Despite routine antacid prophylaxis, a large proportion of our emergency patients remain at risk for aspiration pneumonia. We thus concur with the recommendation that the stomach should be aspirated during general anaesthesia for emergency caesarean section.

Journal Article↗

Aortic pH oscillations in conscious humans and anaesthetised cats and rabbits.

Respiratory oscillations in arterial blood gas composition influence breathing in cats and dogs. Their role in the control of breathing in humans in less certain. To determine whether oscillations are very small or absent in mammals who are large or breathe fast, aortic pH oscillations, recorded with a tridodecylamine based hydrogen-ion selective electrode, were compared in humans (n = 13), cats (n = 7) and rabbits (n = 4) over a wide range of ventilation. For comparison, data were analysed in terms of the ratio of tidal volume to functional residual capacity (VT/FRC). During spontaneous breathing in rabbits, cats and humans (mean respiratory frequency fR = 61, 20.4 and and 17.5 min-1), mean VT/FRC were 1.35, 0.63 and 0.36 respectively. Corresponding pH amplitudes (pHamp) of 0.009 (0.004), 0.016 and 0.013 (0.005) pH units (mean +/- 1SD) were not significantly different. The pHamp decreased exponentially with increasing FR in each species and pHamp increased linearly with increasing VT in the 3 cats in which this was studied. The study confirms the dependence of pHamp on FR and VT and its comparability among species despite differences in body size. It also demonstrates that oscillations can be recorded in humans at FR in excess of 20 min-1.

Acid-Base Equilibrium↗

Fluid requirements of patients with burns and inhalation injuries in an intensive care unit.

We have studied 9 patients with burns (20%-75%) who had inhalation injuries and compared their actual fluid requirements with their requirements calculated from the Muir and Barclay formula. All patients were resuscitated with plasma protein fraction at a rate sufficient to keep their physiological variables within the following range: heart rate less than 120/min, central venous pressure 8-12 cm H2O, urine output greater than 30-50 ml/h, systolic blood pressure greater than 90 mm Hg and diastolic blood pressure greater than 60 mm Hg. The amount of plasma protein fraction needed was 4.38 +/- 1.26 ml/kg/% burn in the first 24 h and 2.15 +/- 0.97 ml/kg/% burn in the second 24 h. This is an increase of 75% and 110% respectively above values predicted from the formula. We suggest that the observed difference is due to a combination of the presence of an inhalation injury which increases fluid requirements by approximately 30% in the first 24 h and the use of plasma protein fraction rather than the dried plasma used in the original Muir and Barclay formula.

Adult↗

Masked vitamin B12 and folate deficiency in the elderly.

1. A high incidence of vitamin B12 or folate deficiency, or both, may be found in the elderly, particularly those in hospital. This report concerns fifty cases detected in an inner-city-area geriatric unit during the course of routine clinical investigation. The majority had none of the classical haematological signs of vitamin B12 or folate deficiency, and all the patients reported had a mean corpuscular volume (MCV) of less than 100 fl. 2. There was a significant negative correlation between the MCV and the erythrocyte folate (P less than 0.01), supporting earlier published work using a low serum folate as an index of folate deficiency. 3. There was no correlation between the MCV and the serum vitamin B12. Published work differs on this point. 4. Serum iron, total Fe-binding capacity and percentage Fe saturation results were available in forty patients in this series. There was a significant positive correlation between the serum Fe and the MCV (P less than 0.01) and 34% of patients had haematological evidence of Fe deficiency. In the majority, however, there was no evidence that associated Fe deficiency had masked the haematological signs of vitamin B12 or folate deficiency. 5. More attention should be paid to the problem of 'masked' vitamin B12 and folate deficiency in the elderly. There is a case for routine screening of the elderly for vitamin B12 and folate deficiency irrespective of the MCV.

Aged↗

Neostriatal administration of somatostatin:differential effect of small and large doses on behavior and motor control.

The administration of small doses of somatostatin (SRIF) (0.01 and 0.1 microgram) into the neostriatal complex of unrestrained, freely moving rats induced general behavioral excitation associated with a variety of stereotyped movements, tremors, and a reduction of rapid eye movements (REM) and deep slow wave sleep (SWS). In contrast, the higher doses of SRIF (1.0 and 10.0 microgram) caused movements to be uncoordinated and frequently induced more severe difficulties in motor control such as contralateral hemiplegia-in-extension which restricted or completely prevented the expression of normal behavioral patterns. As a result, the animals appeared drowsy and inhibited. Analysis of the sleep-waking cycle revealed prolonged periods of a shallow SWS while REM sleep and deep SWS were markedly reduced; electroencephalogram recordings revealed periods of dissociation from behavior. The administration of endocrinologically inactive as well as the active analogues of SRIF failed to induce effects comparable with those observed after the administration of the same dose of the native hormone (10.0 microgram).

Animals↗

Cortical administration of somatostatin (SRIF): effect on sleep and motor behavior.

Cortical administration of SRIF in unrestrained, freely moving rats produced an early activation, stereotyped behavior patterns and later, coordination difficulties often associated with drowsiness. A few animals showed a tendency toward paraplegia-in-extension. A considerable, prolonged alteration in the sleep-waking cycle was also observed. Similar results were obtained in both intact and hypophysectomized animals. Intraperitoneal administration of SRIF induced several other effects in addition to those seen after cortical application. The latter were however, restricted in variety, intensity and duration.

Animals↗