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Biomedical subjects

D C Flenley

Publications and source records attributed to D C Flenley.

At least 91 records · Page 5Linked to original sources
PubMed1982

The renal glomerulus in hypoxic cor pulmonale.

We measured the mean capillary tuft area by a custom-built semi-automatic technique in postmortem sections from the kidneys of 16 patients with "blue and bloated" chronic bronchitis and emphysema and in seven patients of similar age who were free of respiratory and renal disease at death. Nine bronchitic patients had received domiciliary oxygen treatment while seven had not. The mean glomerular tuft area in these treated bronchitic patients (14 200 microns2) was not significantly different from that of the untreated patients (16 900 microns2) but the tuft area in the bronchitic subjects was significantly larger than that of the non-bronchitic controls (12 100 microns2, p less than 0 . 02). There was no reduction in glomerular cellularity to suggest passive venous distension, and glomerular size was not correlated with clinical or pathological indices of cor pulmonale (including red cell mass). The arterial oxygen tension (Po2), however, was correlated with glomerular size (r = 0 . 68, p less than 0 . 01) if allowance was made for the higher Po2 of the patients receiving oxygen. The percentage of glomeruli with an identifiable juxtaglomerular apparatus also increased with increasing glomerular size. These structural changes in the kidneys of patients with severe chronic bronchitis and emphysema may reflect changes in renal salt and water handling that are potentially reversible by oxygen treatment.

Aged↗
PubMed1982

Cigarette smoking and secondary polycythemia in hypoxic cor pulmonale.

We have related the red cell mass (RCM) in 47 hypoxic patients with COPD (mean PO2, 52.5 +/- 5.2 SD mmHg; mean PCO2, 51.7 +/- 6.7 mmHg; mean/FEV1, 0.6 +/- 0.2 L; mean FVC, 1.7 +/- 0.6 L) to their smoking habits and outpatient carboxyhemoglobin concentrations. The mean RCM was 42.5 +/- 8.0 ml/kg in the 31 patients who still smoked, significantly (p less than 0.01) higher than in the 16 who were currently nonsmokers (RCM, 29.7 +/- 4.4 ml/kg). Measurements of arterial PO2, pH, P50, and COHb showed that the saturation of available hemoglobin (SO2A) was less well correlated (r = -0.36, p less than 0.05) with RCM in the smokers, than was SO2T (r = -0.58, p less than 0.001), SO2T including a corrective term for COHb. The RCM correlated well with the mean outpatient COHb measured repeatedly over 6 to 36 months in 40 of the patients but poorly with thier average arterial oxygen saturation (r = 0.15, p less than 0.1). In 15 patients given long-term oxygen therapy (15 hours/24-hour period) for 12 months RCM decreased significantly only in those who stopped smoking, as shown by a decrease in COHb. We conclude that cigarette smoking may determine the severity of secondary polycythemia in patients with hypoxic COPD, and prevent its correction by long-term oxygen therapy.

Carboxyhemoglobin↗
PubMed1981

Carbon monoxide and exercise tolerance in chronic bronchitis and emphysema.

The effects of carbon monoxide on exercise tolerance as assessed by the distance walked in 12 minutes were studied in 15 patients with severe chronic bronchitis and emphysema (mean forced expiratory volume in one second 0.56 1, mean forced vital capacity 1.54 1). Each subject walked breathing air and oxygen before and after exposure to sufficient carbon monoxide to raise their venous carboxyhaemoglobin concentration by 9%. There was a significant reduction in the walking distance when the patients breathed air after exposure to carbon monoxide (p less than 0.01), and the significant increase in walking distance seen after exercise when breathing oxygen at 2 1/minute via nasal cannulae was abolished if carbon monoxide has previously been administered. Thus concentrations of carboxyhaemoglobin frequently found in bronchitic patients who smoke may reduce their tolerance of everyday exercise, possibly by interfering with the transport of oxygen to exercising muscles.

Bronchitis↗
PubMed1981

Reduced airway vagal tone in diabetic patients with autonomic neuropathy.

1. Forced expiratory flow rates and specific airways conductance were measured before and after the inhalation of the atropine-like drug ipratropium bromide in 11 diabetic patients with autonomic neuropathy and a control group of 11 diabetic patients without autonomic neuropathy. Respiratory muscle function was assessed by recording maximal inspiratory and expiratory mouth pressures. 2. There was no difference between the two groups of diabetic patients in airway calibre before ipratropium bromide or in maximal mouth pressures. 3. Bronchodilatation after ipratropium bromide was greater in the control group than in the autonomic neuropathy group of patients. 4. It is concluded that, despite the lack of clinical evidence of respiratory involvement, patients with diabetic autonomic neuropathy have reduced airway vagal tone.

Adolescent↗
PubMed1980

Arterial puncture.

Explore the source record for details and available documents.

Acid-Base Imbalance↗
PubMed1980

Respiratory failure revisited: acute exacerbations of chronic bronchitis between 1961-68 and 1970-76.

Factors determining survival have been analysed retrospectively in 157 admissions of 135 patients with an acute exacerbation of chronic bronchitis and emphysema causing hypoxaemia and carbon dioxide retention. All were treated with controlled oxygen therapy. The death-rate increased with the age of the patient, but was not correlated with the age of the patient, but was not correlated with the severity of hypoxaemia on admission, when the patient was breathing air. The death-rate was significantly higher in those patients in whom arterial [H+] rose above 55 nmol/1 (pH = 7.26) during controlled oxygen therapy. The absence of a rise in the arterial PCO2 during controlled oxygen therapy was not necessarily indicative of a good prognosis, since 5 out of 18 patients showing this response subsequently died in that admission. Only 28% of the 111 patients who left hospital alive survived for five years.

Acidosis, Respiratory↗
PubMed1980

Arterial blood gas tensions and pH.

1 The definition of PO2 and its relationship to the oxygen saturation (SO2) by the oxygen dissociation curve (ODC) is described with details of the ligands of the ODC and the effects of haemoglobinopathies on P50 (the position of the ODC) and the slope of the ODC (Hill's 'n'). 2 The definition of PCO2 and description of CO2 transport by blood leads to consideration of the basis of acid base balance. 3 Acid base balance is expressed in terms of arterial blood (H+) (or pH) PCO2 relationship using a non-logarithmic diagram. 4 The measurement of arterial blood gas tensions is described with comments on arterial puncture and available modern automated blood gas electrodes and their calibration. 5 Non-invasive indirect measurements of blood gas tensions, by ear oximetry are described, with calibration figures on the Hewlett-Packard 47021A ear oximeter. End-tidal PO2 and PCO2 measurements by mass spectrometer or infra-red CO2 analyser, and of transcutaneous PO2 measurements by a heated polarographic electrode are described. 6 These measurements are necessary to study the effects of pharmacological agents on the chemical control of breathing, on pulmonary gas exchange, and on acid base balance in humans. The measurements are in everyday use in clinical practice, both to aid diagnosis of respiratory diseases, assess their severity, and to quantiate the effects of therapeutic agents.

Acid-Base Equilibrium↗
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

Transient hypoxaemia during sleep in chronic bronchitis and emphysema.

Arterial oxygenation, breathing pattern, and electroencephalogram were studied during sleep in patients with chronic bronchitis and emphysema and in healthy subjects. All of the 10 "blue and bloated" patients had episodes of transient hypoxaemia lasting 1--100 min, when their oxygen saturation fell by more than 10%, whereas such desaturation did not occur in 2 "pink and puffing" patients or in 4 healthy subjects. Hypoxaemic episodes usually occurred during the rapid-eye-movement stage of sleep. It is suggested that these hypoxaemic episodes result from a combination of hypoventilation and impaired ventilation/perfusion relationships and that these episodes may contribute to the development of the pulmonary hypertension and secondary polycythaemia which characterises "blue and bloated" patients.

Adult↗