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Biomedical subjects

G H Hulands

Publications and source records attributed to G H Hulands.

At least 19 recordsLinked to original sources
PubMed1987

Serum fluoride levels in morbidly obese patients: enflurane compared with isoflurane anaesthesia.

Obese patients are known to metabolise anaesthetic agents more than patients of normal weight. The extent of this was investigated by the measurement of serum fluoride concentrations in 10 morbidly obese patients undergoing gastroplasty. Five were allocated to receive enflurane and five to receive isoflurane supplemented anaesthesia. The mean peak serum fluoride concentrations after enflurane anaesthesia were greater (22.7 mumol/litre, SE 2.9) than after isoflurane anaesthesia (6.5 mumol/litre, SE 0.6). The mechanisms and implications of this finding are discussed.

Adult↗
PubMed1984

The effect of nicotine on pulmonary epithelial permeability in man.

We examined the effect of nicotine on pulmonary epithelial permeability in man. Nicotine was administered from a chewing gum base given over a seven-day period. An index of pulmonary permeability was derived from the rate of clearance from the lung into the blood of 99mTcDTPA (diethylenetriamine pentacetate). In five nonsmoking volunteers there was no change in permeability for the seven-day study period. This lack of effect of nicotine alone was in striking contrast to the increase in epithelial permeability observed in five nonsmoking subjects who took up cigarette smoking.

Adult↗
PubMed1980

Protective effect of steroids on cultured cells damaged by high concentrations of oxygen.

Chromosomal aberrations resulting from the exposure of Chinese hamster lung fibroblast cells to 95% oxygen have been used to investigate the protective effect of three steroids. Hydrocortisone had little useful effect. However, dosage of both methylprednisolone and dexamethasone could be increased to a level at which damage by oxygen was reduced to 50% of nuclei compared with 90% damaged in cells unprotected by steroids. There was no appreciable impairment of cell growth. Concentrations of steroids required for this effect were respectively 100 and 10 mumol litre-1, which corresponds to the high dosage regimen currently used to protect the lungs against the effects of endotoxic shock, haemorrhage and other conditions. The steroids did not protect against the depression of cell growth caused by 95% oxygen.

Animals↗
PubMed1980

Systemic and local effects of the application of a tourniquet.

The effect of the application of a tourniquet to a limb and the release of the accumulated metabolites have been investigated with reference to the acid-base level in the blood from the limb and in the right atrium. Investigations have been carried out experimentally in rhesus monkeys and observations have been made on patients undergoing reconstructive operations on the knee. The acidotic blood from the ischaemic limb produces little systemic effect. The limb recovers in approximately 40 minutes after a tourniquet has been in place for four hours. Three hours is recommended as a reasonable upper limit for the safe application of a pneumatic tourniquet.

Acid-Base Equilibrium↗
PubMed1979

Alveolar-capillary membrane permeability. Correlation with functional, radiographic, and postmortem changes after fluid aspiration.

An index of permeability of the alveolar-capillary membrane was derived from the relative extraction from the lung into arterial blood of 2 tracers, 125I-antipyrine and 51Cr-ethylenediaminetetraacetate. The effect on this index of aspirating 2 ml of isotonic saline, distilled water, or 10(-1) M hydrochloric acid per kg of body weight was studied in 3 groups of rabbits. The severity and time course of changes in the permeability index were correlated with changes in lung mechanics, gas exchange, serial chest roentgenograms, ratio of extravascular lung water to dry weight, and histologic findings. Aspiration of saline produced no change in the permeability index; aspiration of water produced a large mean +/- SEM increase in the index, from a baseline of 0.025 +/- 0.002 to 1,050 +/- 0.054 (P less than 0.001), but this value returned to baseline 15 min later. After hydrochloric acid, the permeability index increased from a baseline of 0.027 +/- 0.003 to 1.068 +/- 0.098 (P less than 0.005), with no evidence of resolution after 60 min. Changes in lung mechanics, gas exchange, and roentgenograms were smallest after aspiration of distilled water and greatest after aspiration of hydrochloric acid. The functional changes after aspiration of water and saline recovered at a rate proportional to the known clearance rates of these liquids from the lung. The changes after hydrochloric acid either showed no tendency toward recovery or, in the case of the roentgenograms, worsened with time. There were no detectable histologic abnormalities or an increase in the ratio of extravascular lung water to dry weight after aspiration of water or saline, but there were extensive histologic abnormalities and a 70 per cent increase in lung water after acid. The increase in the permeability index after aspiration of water was too transient to exert a deleterious effect. In contrast, the persistence of the increase in the permeability index after hydrochloric acid was associated with persistent functional changes attributable to the considerable increase in lung water.

Animals↗
PubMed1974

Functional residual capacity during anaesthesia. I: Methodology.

The helium dilution technique for the measurement of functional residual capacity (FRC) is reviewed with special reference to anaesthesia. A modification is described which permits measurements to be made during intermittent positive pressure ventilation. This modification causes minimal interference with the circuit as it is used for spontaneous respiration. The measuring circuit may be alternated with an open circuit without disturbance of the pattern of breathing (spontaneous or artificial). Potential errors in the measurement of FRC during anaesthesia are considered and assessment of linearity, reproducibility and accuracy is described.

Anesthesia↗
PubMed1974

Functional residual capacity during anaesthesia. II. Spontaneous respiration.

Functional residual capacity has been measured by helium dilution in 26 spontaneously breathing patients before and immediately after anaesthesia, which was induced with thiopentone and maintained with halothane. The mean reduction was 390 ml (16.1% or pre-induction value) and the change was highly significant (P less than 0.001). The decrease in FRC correlated with age (r equals 0.41: P less than 0.005) and less (P less than 0.001). The decrease in FRC correlated with age (r equals 0.41; P less than 0.005) and less satisfactorily with the weight/height ratio (r equals 0.31; P less than 0.05) which itself correlated with age. Inspired oxygen concentration, expiratory reserve volume and the presence of phasic expiratory muscle activity bore no significant relationship to the decrease in FRC. There was no evidence of any progressive change in FRC between 6 and 20 min after the induction of anaesthesia.

Adult↗
PubMed1974

Functional residual capacity during anaesthesia III: Artificial ventilation.

The helium dilution technique has been used to measure the FRC of 13 patients before and during anaesthesia with paralysis and artificial ventilation, and also in 5 conscious subjects during spontaneous and artificial ventilation without paralysis. After induction of anaesthesia the mean reduction in FRC was 297 ml or 15.4% of the preoperative value and the change was highly significant (P is smaller than 0.005). In the conscious subjects, the FRC was reduced in every case during artificial ventilation by a mean value of 99 ml or 4.1% of original value. This change was also significant. The anaesthetized patients breathed 35% oxygen before and during anaesthesia. The (A-a) PO2 difference increased from a mean value of 49.1 mm Hg before anaesthesia to a mean of 79.7 mm Hg during anaesthesia, the change being highly significant (P is smaller than 0.001). Individual changes correlated with the reduction in FRC (P is smaller than 0.005).

Adult↗