Biomedical subjects

M F Sudlow

Publications and source records attributed to M F Sudlow.

At least 37 records · Page 2Linked to original sources

PubMed1982

Protective effect of drugs on bronchoconstriction induced by sulphur dioxide.

The response to inhaled sulphur dioxide in eight normal, seven atopic, and 22 asthmatic subjects was studied by measuring thoracic gas volume and airway resistance in a whole-body plethysmograph. The fall in specific airway conductance in relation to the concentration of sulphur dioxide inhaled (0-20 ppm) was determined in all three groups. The specific airway conductance fell significantly in the atopic and asthmatic subjects but not in the normal group. In a double-blind study prior inhalation of disodium cromoglycate caused a significant reduction in the response to sulphur dioxide inhalation in atopic and asthmatic subjects. Prior treatment with inhaled ipratropium bromide blocked the response in the atopic subjects, but the effect was variable in the patients with asthma. Previous treatment with inhaled clemastine also reduced the response in patients with asthma, without causing a change in baseline specific conductance. We conclude that non-allergic bronchial hyperreactivity was increased in the atopic and the asthmatic subjects and that mediator release, in addition to a vagal reflex, has a role in such bronchoconstriction.

Adolescent↗

PubMed1981

Bronchial needle aspiration in the diagnosis of bronchial carcinoma.

Sixty consecutive patients with central bronchial carcinomas were studied by fibreoptic bronchoscopy. In all forceps biopsy and bronchial needle aspiration were performed, and in 54 bronchial brushings were obtained. The combination of bronchial brushings and forceps biopsy diagnosed bronchial carcinoma of a defined cell type in 80% of patients. Bronchial needle aspiration was the most effective single technique giving a cytological diagnosis in 80% of patients, and when all three techniques were combined the positive rate increased to 92%. No major complications occurred using bronchial needle aspiration. Needle aspiration was particularly helpful when sampling from lesions in the upper lobes where forceps biopsies were technically difficult, from tumours lying submucosally, and from abnormalities caused by extrinsic compression. We conclude that bronchial needle aspiration should be used routinely, together with other sampling techniques, in the diagnosis of central bronchial carcinoma with the fibreoptic bronchoscope.

Biopsy↗

PubMed1981

Breathing at low lung volumes and chest strapping: a comparison of lung mechanics.

In six normal subjects forced expiratory flow rates increased progressively with increasing degrees of chest strapping. In nine normal subjects forced expiratory flow rates increased with the time spent breathing with expiratory reserve volume 0.5 liters above residual volume, the increase being significant by 30 s (P less than 0.01), and flow rates were still increasing at 2 min, the longest time the subjects could breathe at this lung volume. The increase in flow after low lung volume breathing (LLVB) was similar to that produced by strapping. The effect of LLVB was diminished by the inhalation of the atropinelike drug ipratropium. Quasistatic recoil pressures were higher following strapping and LLVB than on partial or maximal expiration, but the rise in recoil pressure was insufficient to account for all the observed increased in maximum flow. We suggest that the effects of chest strapping are due to LLVB and that both cause bronchodilatation.

Adult↗

PubMed1980

Computer measurement of dynamic compliance: technique and reproducibility in man.

A computer program was developed to calculate the frequency dependence of dynamic compliance (Cdyn) using continuous data analysis. Cdyn was measured repeatedly in eight normal human subjects over a 2-yr period. Comparison with Cdyn results measured manually showed that the computer program improved 10-fold the ratio of variance within subjects to between subjects of the compliance at specific frequencies, but there was only slight improvement in indices of the slope of the frequency dependence of compliance. We suggest that the absolute compliance at specific frequencies merits further consideration as a pathophysiological measurement and that, if the frequency dependence of compliance continues to be used, standardization of its calculation should be applied and the wide normal range should be more widely appreciated. Measurements of Cdyn in subjects breathing 80% helium-20% oxygen confirm that inertia is insignificant when breathing with tidal volumes of less than 500 ml and frequency of less than 1.5 Hz.

Diagnosis, Computer-Assisted↗

PubMed1979

Bronchodilatation and the site of airway resistance in severe chronic bronchitis.

Twenty-one patients with severe chronic bronchitis and emphysema (FEV1 less than 1 1) inhaled 80 microgram of the atropine-like agent ipratropium or placebo in a double-blind study and three hours later inhaled 200 microgram salbutamol. After 80 microgram ipratropium, mean FEV1 was significantly greater than after 200 microgram salbutamol (P less than 0.025), but the difference was only 40 ml and the clinical significance of this difference is unproved. There was no correlation between the patient's response to ipratropium and the response to salbutamol. When salbutamol was administered three hours after ipratropium, the FEV1 rose to higher levels than after either agent alone (P less than 0.01). Studies breathing 80% helium/20% oxygen suggest that ipratropium dilates both large and small airways. There was no correlation between the response to helium/oxygen and the response to either bronchodilator. The results suggest that in severe chronic bronchitis and emphysema ipratropium is at least as effective as salbutamol, and that such patients should have reversibility studies with salbutamol alone, ipratropium alone, and after both agents together. The combination of ipratropium and salbutamol may be clinically useful.

Aged↗

PubMed1979

Effect of an inhaled atropinelike agent on normal airway function.

Ten normal subjects inhaled 80 microgram ipratropium or placebo. Body plethysmograph studies showed that ipratropium increased specific conductance (0.14-0.21 s-1.cmH2O-1) and increased flow rates during both maximal and partial forced expiratory maneuvers at all volumes from 50 to 10% vital capacity (P less than 0.01). Ipratropium produced no change in quasi-static or dynamic compliance, closing volume, or the slope of phase III of the closing volume trace, but there was an increase in the height of phase IV (P less than 0.01). Specific conductance reflects central airways caliber, whereas flow rates at low lung volumes in the absence of alteration in static recoil pressure may reflect the caliber of more peripheral airways. We conclude that inhibition of vagal tone results in dilatation of large and small airways. Analysis of the flow volume results on the equal pressure point model suggests that the bronchodilatation normally resulting from the inhalation to total lung capacity is not solely due to inhibition of vagal tone.

Adult↗

PubMed1975

Acute effects of smoking tobacco and a tobacco substitute on lung function in man.

The acute effects on airway function of smoking one cigarette of a tobacco substitute 'New Smoking Material' (NSM), one cigarette of conventional tobacco, and one cigarette containing 70% tobacco and 30% NSM, were studied in 6 healthy nonsmokers and 6 healthy smokers. None of the cigarettes produced any change in three tests of small-airway function (flow-volume curves, closing volume, frequency dependence of compliance). However, smoking either one conventional tobacco cigarette or the 30% NSM/70% tobacco cigarette produced an acute fall in specific airways conductance, of similar degree with both cigarettes, whereas the 100% NSM cigarette produced no such change.

Adolescent↗

PubMed1975

Cardiorespiratory effects of rapid saline infusion in normal man.

We have studied the cardiorespiratory effects of the rapid infusion (100 ml/min) of 2 liters of saline in four normal seated subjects. Cardiac output and pulmonary arterial pressure increased, while vital capacity (VC) and total lung capacity (TLC) decreased. There was an increase in closing volume (CV) without any detectable change in lung compliance or flow-volume characteristics. There was an increase in Pao2 during infusion period which can be related to better matching of ventilation to perfusion and to improved hemoglobin transport. In the recovery stage as cardiac output, pulmonary arterial pressure, TLC, and VC all returned toward control values CV remained high. In two subjects CV occurred within the normal tidal range of ventilation and in these two subjects Pao2 fell significantly below values obtained in the control period. The results suggest that rapid saline infusion in man can cause interstitial edema and lead to premature airway closure and hypoxemia.

Airway Resistance↗

PubMed1974