PubMed Health⌕ Search

Biomedical subjects

P M Tweeddale

Publications and source records attributed to P M Tweeddale.

At least 19 recordsLinked to original sources
PubMed1994

Breathing retraining: effect on anxiety and depression scores in behavioural breathlessness.

Thirty-six patients underwent assessment of behavioural breathlessness which included monitoring of breathing patterns and end tidal CO2 concentration and completion of questionnaires relating to hyperventilation (HV), anxiety and depression. Twenty-two patients had a positive assessment and underwent breathing retraining. Assessments were repeated immediately after re-training and 2 months later. Ten of the patients (Group A) had behavioural breathlessness either as the primary problem or secondary to an established clinical condition, and twelve (Group B) in association with chronic fatigue. Before re-training, resting end-tidal PCO2 was significantly lower in Group A than Group B (p < 0.05), but there was no significant difference in mean scores for HV-related symptoms, anxiety or depression. Following breathing retraining, both groups showed improvements in breathing patterns, end tidal CO2 levels and scores for HV-related symptoms which were sustained. In Group A the mean score for anxiety decreased (p < 0.01) and the score for depression was significantly lower than in Group B (p < 0.05). Although mean scores for anxiety and depression in Group B did not change significantly, some individuals in the group did show sustained improvement. There was no improvement in symptoms associated with chronic fatigue in Group B. In behavioural breathlessness, breathing retraining is of benefit, not only in restoring more normal patterns of breathing but also in reducing anxiety, particularly in patients without the complication of chronic fatigue.

Adult↗
PubMed1994

The effect of pulmonary function of local and loco-regional irradiation for breast cancer.

Eighty-five patients treated with loco-regional radiotherapy to the breast/chest wall and cervico-axillary nodes, and 16 patients treated with local radiotherapy to the breast/chest wall alone for breast cancer were enrolled in a prospective study to measure the effects of treatment on pulmonary function during the acute phase (10 weeks after completing irradiation) and during the late phase (12 months after completing irradiation). Baseline pulmonary function values were obtained from all patients immediately prior to commencing radiotherapy. Twenty-two patients (25.8%) treated with loco-regional radiotherapy developed transient chest symptoms compared with two patients (12.5%) treated with local radiotherapy (P = 0.11). Patients undergoing loco-regional radiotherapy showed a reduction of mean vital capacity of 0.13 litres (4.2%) (P < 0.0001) during the acute phase and at 1 year a further decrease occurred (P = 0.02) so that mean vital capacity was reduced by 0.18 litres (5.8%) (P < 0.0001) compared to pretreatment values. Mean transfer factor for carbon monoxide (TLCO) was reduced by 0.85 mmol.kPa-1.min-1 [11.9%] (P < 0.0001) during the acute phase and remained unchanged at 1 year. Patients undergoing local radiotherapy to the breast/chest wall alone did not show any significant loss of vital capacity but mean TLCO was reduced during the acute phase by 0.65 mmol.kPa-1.min-1 (8.3%) (P < 0.002) which remained unchanged at 1 year. No significant association was found between impairment of ventilation or gas transfer and respiratory history, smoking history, concurrent respiratory symptoms, age, side treated or physiological pulmonary function in either the acute or late phase. This study has quantified some of the physiological sequelae following local and loco-regional radiotherapy for breast cancer. There is no evidence to suggest that any of the above factors are relevant to deciding which patients should, or should not, be offered local or loco-regional radiotherapy for breast cancer.

Breast Neoplasms↗
PubMed1989

Pulmonary function in childhood leukaemia survivors.

Little is known of pulmonary function in survivors of acute lymphoblastic leukaemia (A.L.L.); this is despite the fact that some drugs used, most notably methotrexate, have well-recorded pulmonary toxicity, and the most common infections during therapy in most series are of upper and lower respiratory tract. As part of a survey of all cancer survivors attending the Royal Hospital for Sick Children in Edinburgh, 38 leukaemic patients, who had completed treatment 3 months to 14 years 6 months (median 6 years and 8 months) prior to survey were assessed with regards to their respiratory status. Each patient completed a questionnaire and had spirometry and lung volumes measured; 30 patients additionally had transfer factor for carbon monoxide (TCO) measured. There were 21 children, 11 adults, and 6 patients in the age range between child and adult. Of the 26 adults and children studied with complete data available, 17 (65%) had one or more low values for vital capacity (VC), total lung capacity (TLC), residual volume, or TCO. Mean VC, TLC and TCO were significantly lower than the mean of the predicted values (P less than .001). Gas transfer per unit lung volume (KCO) was normal in all cases. Few patients had symptoms of respiratory disease. There was an increased incidence of low TCO in patients diagnosed under 8 years of age. Impairment of lung growth could be a contributing factor to the observed abnormalities in pulmonary function. Impairment of pulmonary function in survivors of A.L.L. may be of significance for them in later life.

Adolescent↗
PubMed1987

A standardised comment scheme for routine pulmonary function test results.

Observed values of ventilatory capacity, gas transfer and lung volumes in 840 patients were used to formulate a standardised scheme of descriptive comments. Response to bronchodilators was also defined. Absolute differences between measured and predicted values are used to identify normal and abnormal patterns of results, together with an overall pattern. The algorithms are suitable for computer use. The scheme has been in routine manual use for four years and can be used by any laboratory in which the necessary quality control standards are applied.

Adult↗
PubMed1987

Short term variability in FEV1 and bronchodilator responsiveness in patients with obstructive ventilatory defects.

Short term variability in FEV1 and responsiveness to inhaled bronchodilator were measured in 150 patients with obstructive ventilatory defects. The range of initial FEV1 was 0.5-4.71 and the natural variability over a 20 minute period when expressed in absolute terms was similar over the entire range, and differed insignificantly from that found in normal subjects. The increase in FEV1 and vital capacity (VC) required to exclude natural variability with 95% confidence in these patients was 160 ml and 330 ml respectively. Natural variability when expressed in percentage terms was negatively correlated with the level of FEV1 recorded. The analysis of changes in FEV1 and VC after administration of bronchodilator used absolute and percentage criteria for response. The number of responders differed considerably according to the criterion used. In those defined by the absolute criterion as responders there was no evidence that size of response was related to level of FEV1. Percentage criteria have traditionally been used to identify responses to bronchodilator that may be clinically useful, while absolute criteria, although statistically valid, have not been favoured. Reappraisal of the criteria used and their limitations and implications is required.

Adolescent↗
PubMed1985

Effects of verapamil and sodium cromoglycate on bronchoconstriction induced by isocapnic hyperventilation.

Twenty-four patients who were known to develop bronchoconstriction in response to isocapnic hyperventilation (IH) took part in a double-blind, placebo-controlled trial to assess the effects of verapamil (5 mg) and sodium cromoglycate (SCG) 20 mg in the prevention of IH-induced bronchoconstriction. Both drug and placebo were inhaled in dry powder form and responses were assessed by serial measurements of forced expiratory volume in 1 sec (FEV1). Sodium cromoglycate was shown to offer significant protection whereas verapamil powder provoked bronchoconstriction in over 40% of patients and these patients appeared to be those with more marked degrees of bronchial reactivity.

Asthma, Exercise-Induced↗
PubMed1985

Evaluation of Biox IIA ear oximeter.

Arterial blood gas tensions, pH, and carboxyhaemoglobin were measured on 322 occasions in 165 patients and the actual oxygen saturation of the haemoglobin (Sao2) was compared with the ear oxygen saturation (SEO2) recorded during the arterial sampling with a Biox IIA ear oximeter. The overall agreement between SEO2 and Sao2 was good, with a mean difference in saturation (SEO2-Sao2) of + 1.5% (SD 3.0). The difference in saturation remained similar at all levels of arterial saturation observed and was unaffected by carboxyhaemoglobin concentration. On four occasions (1% of readings), however, SEO2 and Sao2 differed by more than 10% and such occasional errors might be misleading in clinical practice.

Ear↗
PubMed1984

Short term variability in FEV1: relation to pretest activity, level of FEV1, and smoking habits.

The natural variability in forced expiratory volume in one second (FEV1) over 20 minutes was determined in 54 fit hospital employees and 13 patients with restrictive lung disorders. Initial FEV1 ranged from 1.1 to 6.3 1 BTPS. Variability when expressed as absolute change was similar at all levels of FEV1, so that, when expressed as percentage change, variability decreased with increasing FEV1. Smoking habits did not appear to affect variability but activity before the test did. On the basis of these results an absolute change in FEV1 of 190 ml would be necessary for 95% confidence that the change in FEV1 occurred other than by chance in any one individual. This suggests that the absolute change in FEV1 might be a more reliable criterion than percentage change when distinguishing between natural variability and a response to inhalation of bronchodilators.

Adolescent↗
PubMed1981

Hyperventilation or exercise to induce asthma?

Bronchoconstriction was induced in asthmatic patients by means of isocapnic hyperventilation with dry air. Responses both within a day and between days did not differ significantly and corresponded closely with those observed after exercise. The mean fall in forced expiratory volume in one second (FEV1) observed with both techniques was equivalent to 36%. Isocapnic hyperventilation with dry air, as used in this study, was a potent stimulus and provoked a reproducible response. The method was physically less demanding than exercise and was more acceptable to patients.

Adolescent↗
PubMed1977

Oxygen affinity in vivo and in vitro in chronic ventilatory failure.

1. The oxygen affinity in vitro, haematological indices, erythrocyte 2,3-diphosphoglycerate and plasma inorganic phosphate were determined in 20 patients with chronic ventilatory failure and in 20 healthy non-smokers of similar age. 2. No significant difference was observed between the mean oxygen affinity or phosphate concentrations of the patients and healthy subjects but the mean haemoglobin and packed cell volume were significantly higher in the patients. 3. There was a positive correlation between plasma and intraerythrocytic pH which was similar in both patients and healthy subjects. 4. The arteriovenous difference in oxygen saturation in vivo (directly measured at cardiac catheterization) correlated closely with that calculated from the individual patient's oxygen affinity determined in vitro and arterial and mixed venous oxygen and carbon dioxide tensions, suggesting that oxygen affinity in vitro accurately reflects the curve in vivo.

Adult↗
PubMed1976

Effect of age on oxygen-binding in normal human subjects.

1. Oxygen-binding, plasma and intra-erythrocytic pH, and haemoglobin, 2,3-diphosphoglycerate and inorganic phosphate concentrations were measured in sixty-two healthy non-smokers aged between 18 and 89 years. 2. P50 (oxygen tension at 50% oxygen saturation) expressed at plasma pH 7-40 and PCO2 5-33 kPa showed a positive correlation with age. 3. This correlation of P50 with age was closer when P50 was expressed at a constant intra-erythrocytic pH 7-20. On average P50 at intra-erythrocytic pH 7-20 increased from 3-59 kPa at 20 years to 3-96 kPa at 90 years of age. 4. 2,3-Diphosphoglycerate, inorganic phosphate, haemoglobin and mean corpuscular haemoglobin concentrations did not correlate with P50 or with age.

Adolescent↗
PubMed1975

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

1. The purpose of this investigation was to determine the effects of maternal hyperoxaemia and hypercapnia on the uterine vascular bed and foetal oxygenation in the large white sow at 80-90 days gestation. 2. When maternal hyperoxaemia was induced with 100% oxygen, there was a highly significant rise in the maternal arterial oxygen tension, but no other significant blood gas or vascular changes were observed. 3. When mild maternal hypercapnia was superimposed on maternal hyperoxaemia (oxygen plus 6% carbon dioxide), the oxygen tension and saturation of both the maternal uterine venous and foetal umbilical venous bloods were found when severe hypercapnia was induced (oxygen plus 50% carbon dioxide) but in this case all blood samples showed dramatic changes in PCO2 and pH. These changes were accompanied by an increase in the systemic blood pressure and uterine blood flow, and a decrease in uterine vascular resistance. 4. When mild hypercapnia was induced without hyperoxaemia (air plus 5% carbon dioxide) significant increases were recorded in the oxygen tension and saturation of uterine venous and foetal umbilical venous bloods. Systemic and uterine vascular resistance fell. 5. It was concluded that the increased foetal oxygen tension during maternal hypercapnia was the result of the increased uterine blood flow and greater mass delivery of oxygen to the placenta, so that once the oxygen requirements of the placental tissues themselves were exceeded there would be an increased oxygen gradient at the site of gas exchange. 6. Carbon dioxide concentration in arterial blood plays an important role in determining blood flow through the pregnant uterus in the sow.

Animals↗