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Biomedical subjects

W J Kinnear

Publications and source records attributed to W J Kinnear.

At least 37 records · Page 2Linked to original sources
PubMed1996

Evaluation of the THRESHOLD trainer for inspiratory muscle endurance training: comparison with the weighted plunger method.

Inspiratory muscle training (IMT) has been shown to enhance exercise performance. The weighted plunger (WP) system of inspiratory threshold loading is the most commonly used method of IMT, but is expensive and cumbersome. We have evaluated a commercially available portable spring-loaded IMT device, the THRESHOLD trainer. The WP and THRESHOLD trainer devices were evaluated with their opening pressures set, in random order, at 10, 20, 30 and 40 cmH2O. Using an airpump, pressure at the valve inlet was recorded at the point at which the valve opened, and at airflow rates of 20, 40, 60, 80 and 100 L.min-1. Ten THRESHOLD trainers were then compared using the same opening pressures and airflow rates. Finally, 10 patients with stable chronic heart failure (CHF) inspired, in random order, through the WP and THRESHOLD trainer for 4 min each. The pressure-time product (PTP) was calculated for each 4 min period, to compare the work performed on inspiring through each device. The mean measured opening pressures for the WP set at 10, 20, 30 and 40 cmH2O, were 9.0, 19.3, 27.9 and 39.2 cmH2O, respectively, and there was little change over the range of flow tested. Corresponding values for the THRESHOLD trainer were 7.5, 16.9, 26.2 and 39.1 cmH2O, with the pressure being closer to the set pressure as flow increased to that seen in clinical practice. The 10 different trainers tested performed very similarly to one another. Work performed (as measured by PTP) on inspiring through the WP and THRESHOLD trainer was not significantly different. Although less accurate than the weighted plunger, the THRESHOLD trainer is an inexpensive device of consistent quality. In a clinical setting it would be a satisfactory option for inspiratory muscle training in most patients, but less so in patients with very low inspiratory flow rates.

Breathing Exercises↗
PubMed1995

Time course of resolution of persistent air leak in spontaneous pneumothorax.

Persistent air leak (PAL) following tube drainage for spontaneous pneumothorax (SP) is a potentially troublesome complication. The optimum time to intervene surgically is not known. We therefore investigated the rate of resolution of PAL (defined as continued air leak at 2 days after tube insertion) in patients treated medically. We retrospectively reviewed the records of 214 patients presenting with SP over 5 yr. One hundred and forty-two (67%) had tube drainage and in 73 (51%) of these a PAL developed. Overall median time to resolution in the 43 patients with PAL treated medically was 8 days from tube insertion, but PAL resolution was longer in those with underlying lung disease (n = 19) than those without such disease (11 days vs. 7 days, P = 0.05). In patients with normal lungs 20/24 had resolved by 9 days but subsequently the rate of resolution was much slower. In those with abnormal lungs only 8/19 had resolved by 9 days (P < 0.05 compared with those with normal lungs) but the rate of resolution in such patients appeared to change little subsequently. The size of the initial SP did not influence the rate of resolution of PAL. For patients with PAL and normal lungs, surgery at 7-9 days from tube insertion would provide a reasonable opportunity for the PAL to resolve with medical treatment. For those with underlying lung disease there is no clear optimal time and decisions need to be taken on an individual basis.

Adolescent↗
PubMed1995

Effects of captopril and oxygen on sleep apnoea in patients with mild to moderate congestive cardiac failure.

OBJECTIVES: To determine the effects of captopril and oxygen on sleep quality in patients with mild to moderate cardiac failure. DESIGN: An open observational study. PATIENTS: 12 patients with New York Heart Association class II-III heart failure were studied at baseline. 9 of these patients were then examined at the end of 1 month of treatment with captopril; 9 of the patients were separately assessed during a single night of supplementary oxygen. MAIN OUTCOME MEASURES: Sleep patterns by polysomnography, overnight oximetry, and subjective sleep assessment using visual analogue scores. RESULTS: Abnormal sleep was present in all baseline studies. Complete polysomnograms after treatment with captopril were obtained in 8 patients. Light sleep (stages 1 and 2) was reduced (mean (SEM) 61%(8)% to 48%(6)% actual sleep time, P < 0.05) but slow wave (stages 3 and 4) and REM (rapid eye movement) sleep increased (25%(6)% to 31%(5)%, 14%(2)% to 21%(5)% actual sleep time, P < 0.05). Apnoeic episodes (242(59) to 118(30), P < 0.05), desaturation events (171(60) to 73(37), P < 0.05), and arousals (33(5) to 18(3) P < 0.01) were reduced. Visual analogue scores of sleep quality increased 49(5) to 69(5), P < 0.01). Complete polysomnograms were obtained in 7 patients treated with oxygen. Light sleep duration was reduced (55% (7)% to 42%(5)% actual sleep time, P < 0.05) and slow wave sleep increased (30%(5)% to 38%(6)% actual sleep time, P < 0.05). REM sleep duration was not significantly different. Total arousals (33(6)% to 20(2) P < 0.05), desaturation events (140(33) to 38(10), P < 0.01), and apnoeic episodes (212(53) to 157(33), P < 0.05) were reduced. Visual analogue scores of sleep quality were unchanged. CONCLUSIONS: Captopril and oxygen may improve sleep quality and reduce nocturnal desaturation in patients with mild to moderate cardiac failure. Improved sleep quality could explain the reduction in daytime symptoms seen after treatment in patients with chronic heart failure.

Captopril↗
PubMed1995

Static lung compliance in chronic heart failure: relation with dyspnoea and exercise capacity.

BACKGROUND: The pathogenesis of dyspnoea in patients with chronic heart failure is poorly understood. Static lung compliance is reduced in chronic heart failure. The relation between static lung compliance and exercise capacity and dyspnoea in chronic heart failure has been investigated. METHODS: Static lung compliance was calculated from expiratory pressure-volume curves in 18 patients with chronic heart failure (three women, mean age 62 years). Catheter mounted pressure transducers were used to measure changes in oesophageal pressure. Changes in lung volume were determined by integrating flow at the mouth, measured by a pneumotachograph. New York Heart Association (NYHA) class for dyspnoea was determined by a single observer. Patients underwent treadmill exercise to symptom limited maximum using staged and fixed rate protocols. Borg ratings for dyspnoea at submaximal exercise were measured. RESULTS: Static lung compliance, whether expressed as % total lung capacity (TLC)/cm H2O or % predicted TLC/cm H2O, was unrelated to NYHA class. Similarly, there was no relation between static lung compliance and exercise capacity with either protocol or with Borg ratings for dyspnoea at submaximal exercise, with the exception of that measured after 11 minutes of the staged protocol. CONCLUSIONS: Static lung compliance at rest has no relation with treadmill exercise capacity in chronic heart failure, and its relation with measures of dyspnoea is variable. No role for lung elasticity in determining the symptomatology of chronic heart failure was found.

Cardiac Output↗
PubMed1995

Respiratory muscle strength in chronic heart failure.

BACKGROUND: Several studies have suggested that the respiratory muscles are weak in patients with heart failure, but the aetiology and clinical relevance of this weakness are unclear. In order to see if respiratory muscle weakness in this context is part of a more generalised myopathic process, respiratory and limb muscle strength were compared in patients with heart failure. The relation between respiratory muscle strength, breathlessness on exercise, and exercise capacity was also examined. METHODS: Twenty patients (three women) with New York Heart Association (NYHA) class II-IV heart failure of mean age 63 years were studied. Respiratory muscle strength was assessed using maximum inspiratory and expiratory mouth pressures (MIP and MEP) and transdiaphragmatic pressure during sniffs (sniff PDI). These parameters were compared with cardiac output (indirect Fick) and with limb muscle strength as assessed by grip strength. The patients also performed two exercise tests during which they rated their breathlessness on a Borg scale. RESULTS: Mean (SD) cardiac index was 2.2 (0.4) l/min/m2. MIP and MEP were 66 (27) and 99 (29) cm H2O respectively. Sniff PDI was 103 (21) cm H2O and was positively correlated with grip strength and cardiac output (Spearman rank correlation coefficients 0.527 and 0.451, respectively). None of the indices of respiratory muscle strength were related to exercise time or breathlessness during exercise. CONCLUSIONS: The respiratory muscles are weak in patients with heart failure. This weakness reflects a more generalised myopathic process, possibly related to reduced cardiac output. However, respiratory muscle weakness does not appear to be an important factor in the aetiology of breathlessness on exercise.

Aged↗
PubMed1993

Does Harrington instrumentation improve pulmonary function in adolescents with idiopathic scoliosis? A meta-analysis.

A meta-analysis of the effects of Harrington instrumentation on vital capacity in adolescent patients with idiopathic scoliosis was conducted in an attempt to clarify the conflicting conclusions of different studies. Thirty-eight studies were assessed. Those that did not prevent sufficient statistical information and those that did not allow for normal growth during the interval between tests were excluded. The five studies remaining for analysis, involving a total of 173 patients, showed an increase in mean vital capacity ranging from 2% to 11% of predicted vital capacity. The weighted mean effect size for the five studies analyzed was 0.22 with 95% confidence intervals of 0.01-0.43. The authors conclude that Harrington instrumentation leads to a small but statistically significant improvement in vital capacity.

Adolescent↗
PubMed1993

Normal range for transdiaphragmatic pressures during sniffs with catheter mounted transducers.

BACKGROUND: Transdiaphragmatic pressure (sniff PDI) during maximal sniffs is a useful clinical test of inspiratory muscle function. Although a normal range has been established for sniff PDI using air filled balloons, no comparable data are available for catheter mounted pressure transducers. METHODS: Using a single catheter with two pressure transducers 15 cm apart, oesophageal and gastric pressures were recorded in 50 normal volunteers (25 women), five of each sex from each decade between the third and seventh decades of life. Each subject performed 10 maximal sniffs at functional residual capacity. RESULTS: Mean (SD) sniff PDI was 149 (32) cm H2O in men and 127 (22) cm H2O in women. The lower limits of normal for sniff PDI (mean -1.96 x SD) after logarithmic transformation of the data were 95 and 78 cm H2O in men and women respectively. CONCLUSIONS: With this technique transdiaphragmatic pressure can be measured using a single catheter which can easily be cleaned and reused. The values for sniff PDI are similar to those recorded previously with air filled balloons, suggesting that the method of recording pressure does not significantly affect the values obtained.

Adult↗
PubMed1992

Pulmonary function after spinal surgery for idiopathic scoliosis.

Respiratory function was assessed in 20 patients with idiopathic scoliosis undergoing spinal surgery (median age, 15 years; range, 11-34 years; median preoperative vital capacity, 67%; range, 28-109% predicted). Ten patients underwent anterior spinal surgery through a thoracotomy incision, seven of whom had posterior spinal surgery as a second-stage procedure. The other ten had posterior spinal surgery as their initial operation. Postoperatively, three patients had clinical evidence of respiratory complications. Daytime oxygen saturation was reduced throughout the first postoperative week, with no significant difference between anterior and posterior spinal surgery. Hypercapnia was unusual and generally mild. Vital capacity was reduced significantly 1 week after both anterior and posterior spinal surgery (P less than 0.05). The median vital capacity 1 week after anterior spinal surgery was 45% of preoperative values compared with 78% after posterior surgery (P less than 0.05). Inspiratory muscle strength, as assessed by sniff mouth pressure, was 56% of preoperative values 1 week after anterior spinal surgery (P less than 0.05) and 85% after posterior spinal surgery (not significant). Vital capacity, but not sniff mouth pressure, remained significantly reduced 6 weeks after surgery. Oxygen saturation should be monitored noninvasively during the first week after both anterior and posterior spinal surgery even in patients at low risk of developing respiratory complications.

Adolescent↗
PubMed1992

Respiratory disease in systemic lupus erythematosus: correlation with results of laboratory tests and histological appearance of muscle biopsy specimens.

BACKGROUND: In systemic lupus erythematosus, certain laboratory tests and evidence from muscle biopsy specimens of lymphocytic vasculitis reflect disease activity. A study was designed to determine if such indices predict respiratory lesions, and in particular whether the presence of vasculitis in quadriceps muscle reflects respiratory muscle function. METHODS: Twenty seven 27 patients with systemic lupus erythematosus were studied, ten of whom were consecutive untreated patients and 17 having clinically active disease and being treated. They were prospectively evaluated on the basis of erythrocyte sedimentation rate, lymphocyte count, C3 degradation products, quadriceps muscle biopsy, spirometry, lung volumes, carbon monoxide transfer factor, and mouth pressure during a maximal sniff. RESULTS: Lung function test results were abnormal in 12 patients. Vital capacity was reduced in seven, carbon monoxide transfer factor capacity in five, and mouth pressure was low (< 70% predicted) in ten. Lymphocytic vasculitis was seen in the muscle biopsy specimens of ten patients. No correlation was found between laboratory tests and lung function or mouth pressure, or between the presence of lymphocytic vasculitis and mouth pressure. In untreated patients, those with lymphocytic vasculitis had lower spirometric values. CONCLUSIONS: In systemic lupus erythematosus, evidence from muscle biopsy specimens of lymphocytic vasculitis is not predictive of impaired inspiratory muscle function as measured by mouth pressure. In untreated patients there were relationships between some laboratory test results and respiratory function, but this was not the case for the whole group. In systemic lupus erythematosus, laboratory tests and evidence from muscle biopsy specimens of lymphocytic vasculitis are therefore unlikely to be helpful in the assessment of respiratory disease.

Adult↗
PubMed1991

Comparison of the diagnostic yields of disposable and reusable cytology brushes in fibreoptic bronchoscopy.

Disposable rake and reusable bristle type cytology brushes have been compared in 50 patients undergoing fibreoptic bronchoscopy for suspected malignancy. Forty seven patients were eventually found to have carcinoma of the bronchus. A diagnosis of malignancy was made from the specimens taken with one or other brush in 34 patients, from the reusable brush in 28, and from the disposable brush in 31. The specimens taken with the two types of brush were of similar quality. The reusable brush is about five times less expensive per procedure but carries a risk of cross contamination and cross infection, and time is needed to clean the brush after each bronchoscopy. The diagnostic yield appears to be at least as good with the disposable brush.

Adult↗
PubMed1990

A survey of thoracic actinomycosis.

We have reviewed the case notes of 19 patients with thoracic actinomycosis. The median age at presentation was 42 (range 9-66) years, 15 were male and 12 were urban residents. Cough, sputum production, chest pain and weight loss were the commonest symptoms. Six patients reported haemoptysis. In contrast with the classical appearances of thoracic actinomycosis, only four patients had cutaneous abnormalities, and only one patient had radiological evidence of bone involvement. The provisional diagnosis was bronchial carcinoma in nine patients, and in seven patients the diagnosis of actinomycosis was only made after resection of the lesion, in two cases by pneumonectomy. The median delay between presentation and diagnosis was 3.5 (range 1-24) weeks. Two patients developed extrathoracic complications, but all patients made a full recovery after receiving antibiotic therapy for a median of 6 (range 1-24) weeks. Thoracic actinomycosis is rare, but should still be considered in the differential diagnosis of a pulmonary lesion thought to be malignant.

Actinomycosis↗
PubMed1990

Nosocomial lower respiratory tract infections in surgical wards.

A six month prospective study of nosocomial lower respiratory tract infection was conducted in four general surgery wards and one urological surgery ward. Thirty eight cases were identified, representing 1% of the surgical admissions to these wards. Twenty eight of the infections followed abdominal surgery. Six patients died, five of whom had pre-existing cardiorespiratory disease. Potential pathogens were isolated in 21 patients, the commonest organisms being Streptococcus pneumoniae and Haemophilus influenzae.

Adult↗
PubMed1989

Exercise responses in patients treated for pulmonary tuberculosis by thoracoplasty.

Twenty eight subjects (mean age 64 years) who had been treated for tuberculosis by thoracoplasty in the past performed an increasing work rate exercise test, from which maximum oxygen consumption (VO2max), ventilation and heart rate were measured. VO2max was significantly lower than predicted, being 0.75 l/min in 17 subjects, 1.0 l/min in 10, and 1.5 l/min in one. Only one subject achieved a heart rate of 85% of the predicted maximum. The ratio of heart rate to oxygen consumption (HR/VO2) and heart rate at standard interpolated submaximal levels of oxygen uptake at 0.75 l/min (heart rate 0.75) and 1.0 l/min (heart rate 1.0) were normal. VO2max correlated with ventilation at maximal exercise (VE max) (r = 0.87) and FEV1 (r = 0.47). It did not correlate with resting arterial oxygen or carbon dioxide tensions, FEV1, maximum inspiratory pressure, angle of scoliosis, or number of ribs resected. The relation between ventilation and oxygen consumption (VE/VO2) and VE at the submaximal levels of oxygen consumption of 0.75 l/min (VE 0.75) and 1.0 l/min (VE 1.0) were normal. In 10 subjects a plateau of breathing frequency (fmax) was reached, after which the increase in ventilation was achieved by a further increase in tidal volume (VT). These subjects showed significantly lower values for the forced expiratory ratio, VO2max, and VEmax than those with a normal relation between tidal volume and breathing frequency. VEmax was correlated with FEV1 (r = 0.61), FVC (r = 0.46), maximum VT (r = 0.55), change in VT (r = 0.52), fmax (r = 0.56), and change in breathing frequency (r = 0.72). These results indicate that exercise in patients treated for tuberculosis by thoracoplasty is limited by ventilatory capacity and that this is due to a reduction in both dynamic lung volumes and respiratory frequency.

Aged↗
PubMed1987

Importance of airflow obstruction after thoracoplasty.

Thirty six patients previously treated for pulmonary tuberculosis by thoracoplasty were studied to determine the prevalence and effect of airflow obstruction. The mean (SD) FEV1 was 1.3 (0.65) 1 and the mean forced expiratory ratio (FER) 64% (12%). FEV1 was less than predicted in every patient whereas FER was less than predicted in 30, being below the lower 98th percentile in 15 (42%). In the 18 patients who complained of breathlessness the means of the standardised residuals (SR) for FEV1, peak expiratory flow (PEF), and FER were significantly lower and that for residual volume/total lung capacity (RV/TLC) significantly higher than those for the 18 patients who were not breathless (all p less than 0.0001). There was no difference in the smoking history of the two groups. Only three of the 23 patients in whom reversibility of airflow obstruction was assessed showed a greater than 25% increase in PEF. None showed an increase in FEV1 of greater than 15%. The 18 who were breathless had significantly lower values of arterial oxygen tension (PaO2) and higher values of arterial carbon dioxide tension (PaCO2) (p less than 0.0001). Thirteen of these patients were in chronic respiratory failure (PaO2 less than 8.0 kPa or PaCO2 greater than 5.9 kPa, or both) compared with only one of the 18 who were not breathless. The indices correlating best with PaO2 and PaCO2 were SR FEV1 and SR PEF respectively. SR FEV1 accounted for 34% of the variance in PaO2 and SR PEF for 29% of the variance in PaCO2. Airflow obstruction has been found to be common in patients with a thoracoplasty and to be associated with hypoxia and hypercapnia.

Aged↗
PubMed1987

Late sequelae of pulmonary tuberculosis treated by thoracoplasty.

With the help of information provided by the Office of Population, Censuses and Surveys the survival up to 1 July 1985 of the 171 patients treated for pulmonary tuberculosis by thoracoplasty at Papworth from 1951 to 1953 was determined. Thirteen (8%) could not be traced, 65 (38%) had died, and 93 (54%) were alive. For those who were traced the survival at 10, 20, and 30 years from the date of operation was 93%, 79%, and 65%. This represents a significantly greater mortality rate than that predicted from the Registrar General's review of deaths in England and Wales (1841-1984). Nineteen patients died from cardiorespiratory failure. Eight of the survivors are known to have developed respiratory failure, five having enjoyed apparently good health before this was precipitated by intercurrent illness or drugs. A stepwise logistic regression analysis using information from the 124 patients for whom full details were available showed significant associations between the development of cardiorespiratory or respiratory failure and a preoperative contralateral artificial pneumothorax, older age at operation, the presence of cavities before operation, and male sex. In a questionnaire 50 of the survivors (57% of those who replied) reported cough, 45 (51%) breathlessness, 41 (47%) wheeze, and 24 (27%) ankle swelling. Nineteen (22%) smoke and the same number now attend a chest clinic. Many patients treated for tuberculosis by thoracoplasty have respiratory symptoms and some are at risk of respiratory failure. There are grounds for considering that they should be reviewed periodically by a chest physician.

Adolescent↗
PubMed1985

Abdominal scintigraphy with 99Tcm-labelled red cells in the detection of rebleeding from peptic ulcers.

The technique of 99Tcm-labelled red cell scintigraphy as a means of detecting rebleeding was investigated in 33 patients with bleeding peptic ulcers. Scintigrams were performed twice during the 24 h period succeeding diagnostic endoscopy. There was scintigraphic evidence of rebleeding in 23 patients but this was clinically manifest in 14 patients only. Thirteen of the 14 patients with clinical rebleeding had positive scintigrams while only in one patient with clinical rebleeding was the scintigram negative (P less than 0.05). These results show that rebleeding is common and often clinically inapparent during the first 24 h following gastroscopy but that in the absence of scintigraphic rebleeding serious clinical rebleeding is unlikely to occur.

Adult↗