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PubMed1983

Effects of low concentrations of chlorine on pulmonary function in humans.

Eight healthy unacclimated volunteers were exposed to chlorine gas in concentrations of 0.5 or 1 ppm, and several pulmonary function measurements were made. Comparisons were made by paired t test between the percent change from base-line values obtained at various times after chlorine exposure and the percent change from base line at analogous times after a sham exposure. With the sham vs. 0.5-ppm exposure, there were trivial changes observed. Total lung capacity (TLC) was lower before 0.5-ppm exposure than before sham exposure, and the percent decrease in carbon dioxide pulmonary diffusing capacity was smaller 24 h after 0.5-ppm exposure than 24 h after sham exposure. With the sham vs. 1-ppm exposure, there were many differences in percent change from base line that were significant at the P less than 0.05 level or better. These were in forced vital capacity (FVC), forced expiratory volume at 1 s (FEV1), peak expiratory flow rate (PEFR), forced expiratory flow rate at 50 and 25% vital capacity (FEF50 and FEF25, respectively), and airway resistance (Raw). There were, in addition, significant changes after only 4 h of exposure. These were in FEV1, PEFR, FEF50, FEF25, TLC, Raw, and the difference in nitrogen concentration. Most of the test results had returned to normal by the next day. We conclude that even though chlorine at low concentrations does not produce any serious subjective symptoms, it adversely affects pulmonary function transiently.

Adult↗
PubMed1984

[Study of forced expiratory flow rates in respiratory paralysis].

Subjects with a complete paralysis of the abdominal muscles and severe or lesser involvement of the intercostals were studied. The author analysed, under electromyographic control, the flow-volume curves by measuring flow at 50% (V50) and at 25% (V25) of the observed and theoretical vital capacity (CV) above observed residual volume. The results were compared to a group of normal subjects in three situations: sitting and lying in air and sitting in water. A sloping, head down position was also studied. In the handicapped, instantaneous flow at 50% CV was significantly lower than normals in all situations; at 25% CV the difference was not significant but expiration was incomplete for those sitting in air. For the handicapped, sitting in water, the residual volume was close to that of normal subjects sitting in air and the last part of the flow-volume curve was the same gradient as of normal subjects sitting in air: this enabled some comparisons of instantaneous flow. In order that measures of instantaneous flow were made at the same inflation volume, they were made at 50% and 25% of theoretical vital capacity in the handicapped. The results did not differ from those of normal subjects sitting in air. The situation was less satisfactory lying in air, only useable in practice, the most handicapped subjects having notably reduced outputs compared to those whose motor deficit was less severe. The head down position was as for outputs at very low volume.

Adult↗
PubMedDate not supplied

High prevalence of reversible airway obstruction in asbestos-exposed workers.

In this retrospective study of 97 male workers exposed to asbestos for 2-50 yr, data were collected on chest x-ray findings and lung function, including lung volumes, forced expiratory flow rates (i.e., forced expiratory volume in 1 sec [FEV1.0], forced expiratory flow measured between 25% and 75% of forced vital capacity [FEF(25-75%)]), airway resistance (R(aw)), carbon monoxide (CO)-diffusing capacity, and the existence of airway obstruction reversible by a beta-adrenergic agonist (RAO). The authors performed multiple-regression analyses to correlate the variations in lung function data with age, smoking habits, duration of asbestos exposure, and time since last exposure. Occupational activities of subjects that might induce specific lung abnormalities were also considered. No significant decrease was seen in lung volumes or CO-diffusing capacity; however, a decrease in FEV1.0 and an increase in R(aw) were measured in 65% of the subjects, and an isolated decrease in FEF(25-75%) occurred in only 18%. There was no difference in lung-function data between subjects who had chest x-ray signs of abnormalities (n = 59) and those who did not (n = 38). A significant relationship was found between the decrease in FEV1.0 and age; however, no correlation was noted between altered lung function and cigarette smoking, duration of asbestos exposure, or time since last exposure. RAO prevalence was higher (34%) than previously reported (9%) in subjects with chronic obstructive pulmonary disease (COPD) who were not exposed to asbestos or outdoor pollution. The RAO prevalence in asbestos-exposed workers was nearly the same as that measured in COPD subjects who lived downtown and who were exposed to outdoor pollution (36%). The high RAO prevalence in asbestos-exposed workers was found in 43% of subjects who were exposed only to asbestos, and in 33% of subjects who were also exposed to air pollution due to their occupational activities. It is hoped that the observations in this study will encourage practitioners to check for RAO in asbestos workers who use inhaled bronchodilators.

Aged↗
PubMed2000

Exhaled nitric oxide as an indicator of severity of asthmatic inflammation.

Traditional assessment of severity of asthma relies on an evaluation of signs and symptoms and pulmonary function tests. These pulmonary function tests, such as peak expiratory flow rates, forced vital capacity, and forced expiratory flow rates, are indirect measures of airway caliber only, and not inflammation. Since asthma is an inflammatory disease, a measure of the degree of inflammation would be helpful in quantitating severity and titrating of anti-inflammatory therapy. A noninvasive method for measuring pulmonary inflammation would therefore be helpful to assist the emergency physician in initial treatment and assist in titration of anti-inflammatory therapy during repeat visits. Exhaled nitric oxide (NO) assays are convenient and practical and may fulfill this role. In this review, we discuss the role of NO in asthmatic inflammation and the role that exhaled NO values may play in the emergency management of asthma.

Asthma↗
PubMedDate not supplied

A comparison of autogenic drainage and the active cycle of breathing techniques in patients with chronic obstructive pulmonary diseases.

PURPOSE: The effects of a long-term treatment of autogenic drainage (AD) and the active cycle of breathing techniques (ACBT) were evaluated in patients with chronic obstructive pulmonary disease (COPD). METHODS: Thirty clinically stable male COPD patients were randomly assigned to AD or the ACBT treatment for a 20-day treatment period. Patients were assessed through pulmonary function tests, arterial blood gases, a 6-minute walking test, and a modified Borg Scale before, and immediately after the walking test. RESULTS: Autogenic drainage improved forced vital capacity, forced expiratory volume in 1 second, peak expiratory flow rate, forced expiratory volume from 25 to 75%, chronic hypercapnia, arterial oxygenation, exercise performance, and dyspnea perception during exercise. The ACBT increased forced vital capacity, peak expiratory flow rate, arterial oxygenation and exercise performance. Peak expiratory flow rate increased in AD more than in ACBT. In AD treatment, the increase in oxygen saturation was significantly higher than in ACBT treatment. Chronic hypercapnia improved significantly in AD treatment than in ACBT. No differences were found in other lung function parameters. CONCLUSIONS: Autogenic drainage is as effective as the ACBT in cleaning secretions and improving lung functions. These techniques can be used in stable COPD patients according to the patients' and the physiotherapists' preferences.

Aged↗
PubMed1991

Effect of cigarette smoking on maternal airway function during pregnancy.

The effects of cigarette smoking on maternal airway function during pregnancy were investigated in a cross-sectional study of 97 smokers and 175 nonsmokers at different gestational ages. The groups were comparable in age, height, and weight. All subjects were healthy. Forced vital capacity, forced expiratory volume in 1 second, their ratio, the forced expiratory flow rates between 0.2 and 1.2 L, 25% and 75%, and 75% and 85%, and instantaneous flows at lung volumes of 25%, 50%, and 75% were measured. All spirometric tests were unaffected by gestational age. However, all parameters of spirometry were significantly less in smokers than in nonsmokers when cumulative data during pregnancy were compared. Forced vital capacity, forced expiratory volume in 1 second, and their ratio were minimally reduced (4%, p less than 0.05; 8%, p less than 0.001; and 4%, p less than 0.001; respectively) in smokers as compared with nonsmokers. Larger reductions were noted in forced expiratory flow rates between 0.2 and 1.2 L (14%, p less than 0.001) and between 25% and 75% (16%, p less than 0.001), and in instantaneous maximum flows at lung volumes of 75% (11%, p less than 0.001) and 50% (13%, p less than 0.001). Maximum reduction of forced expiratory flow rates between 75% and 85% (26%, p less than 0.001) and in instantaneous flows at maximum lung volumes of 25% (23%, p less than 0.001) suggests marked increases in small-airway resistance and early small-airway disease in smokers. The progression of small-airway disease is related to the level of cigarette exposure. The results of our study demonstrate that the bronchodilatory effect expected in pregnancy is not sufficient to overcome the deleterious effects of cigarette smoking.

Adult↗
PubMed1975

Comparison of the bronchial response to running and cycling in asthma using an improved definition of the response to work.

The bronchial responses to treadmill running and ergometer cycling have been compared in 13 adults with asthma. The exercises were performed on separate days with an interval ranging from three days to six months. The study was designed to ensure that the time course of oxygen consumption during running was replicated during cycling. The response to exercise was estimated by taking serial measurements of the maximum forced expiratory flow rate and forced expiratory volume in one second before and after work. Indices used to describe the response were (b-a)/b and a/b, where b and a were the average lung function before and the lowest value after exercise respectively. There was no significant difference in the lung function of the subjects before running and cycling nor did the duration of exercise or oxygen consumption differ between the two exercises. Eleven of the 13 patients showed a reduction in ventilatory capacity after both forms of exercise. Differences in the lung function responses to the two forms of standard work were trivial and not statistically significant, amounting to only about 1%. It is suggested that previous reports of larger responses to running than cycling were probably due to higher energy expenditures during running. General problems regarding the description and comparison of the responses to exercise are discussed.

Adult↗
PubMed1979

Changes in pulmonary function after naturally acquired respiratory infection in normal persons.

Changes in pulmonary function due to naturally occurring respiratory tract infection were examinated in 26 normal healthy volunteers during a period of 6 months. Forced expiratory maneuvers in each volunteer were recorded at 2-wk intervals throughout the study and daily during illness. Significant impairment of peak expiratory flow rate, forced vital capacity, forced expiratory volume in one second, and maximal mid-expiratory flow rate at 50% of the vital capacity was observed during infection, whereas changes in the maximal expiratory flow rate at 75% of vital capacity were nonsignificant. From these results, we conclude that large airways are certainly affected during uncomplicated respiratory infections in normal healthy persons and from the changes observed in FVC we suggest that more widespread involvement of the small airways may occur.

Adolescent↗
PubMed1980

Intravenous aminophylline therapy for asthma. A comparison of two methods of administration in children.

Eleven asthmatic children were given intravenous aminophylline by two methods of administration: a 6 mg/kg loading dose followed by a 1.4 mg/kg/hr continuous infusion, or a bolus of 4 mg/kg given every four hours. Expiratory flow rates (forced expiratory volume at 1 s and expiratory flow at 50% of vital capacity) were recorded at intervals for 24 hours with each regimen. Although the intermittent administration of aminophylline produced a substantial improvement, there was a significantly greater pulmonary response to continuous infusion.

Adolescent↗
PubMed1996

Conceptual and methodologic issues in quantifying perceptual accuracy in childhood asthma.

Delineated methodologic issues in the study of symptom perception in childhood asthma. A review of past and recent psychophysiological and clinical studies of both adults and children presents the methodologic and analytic approaches that have been applied to quantify perceptual accuracy. Peak expiratory flow rate, forced expiratory volume in the first second, and force expiratory flow can serve as objective measures of asthma. A visual analog scale, a numerical guess, and a categorical description as subjective measures all have clear strengths and weaknesses. Correlational analysis of subjective-objective data, arithmetic differences between subjective guess and objective value, and an error grid categorization can each be applied to calculate an accuracy index on an individual subject. Illustrative examples reveal that the same data lead to different indices depending on the method chosen. Empirical research is needed to standardize various methodologic approaches. Given the increasing prevalence, severity, and morbidity of pediatric asthma, the study of symptom perception may be a critical component in our understanding of asthma management, and will likely lead to useful clinical interventions.

Adolescent↗
PubMed1989

Normal values for simple lung function tests in South African Asian children.

Normal lung function values have frequently been shown to be racially specific. This study of 1072 boys and girls establishes normal standards for peak expiratory flow rate, forced expiratory volume in 1 s, and forced vital capacity in Asian (Indian) children aged 5-14 years. These values are compared with those of American white and black children and of Indian and British Asians.

Adolescent↗
PubMed1984

A dose response study of oxitropium bromide in chronic bronchitis.

In a dose response study 12 patients with chronic bronchitis and airflow obstruction received inhaled placebo and incremental doses of oxitropium bromide. Significant improvements in peak expiratory flow rate, forced expiratory volume in one second, and forced vital capacity were recorded at all times up to 10 hours after all doses of oxitropium bromide. Oxitropium bromide is an effective bronchodilator in chronic bronchitis with an optimal dose of 400-600 micrograms.

Aged↗
PubMed1990

Relative efficacy of nebulised ipratropium bromide and fenoterol in acute severe asthma.

In a double-blind, randomised, controlled clinical trial of 145 patients with acute asthma, the efficacy of nebulised 4-hourly ipratropium bromide plus 4-hourly fenoterol (group I, 50 patients), 2-hourly fenoterol (group II, 50 patients) and 4-hourly fenoterol (group III, 45 patients) was assessed. All patients received an optimal infusion of aminophylline and 81 patients (27 in each group) received hydrocortisone for clinical indications. It was found that cholinergic side-effects in group I were not more common than in group II. Tremor was more common in group II. Assessment of bronchodilator efficacy was confined to the 81 patients whose therapy included hydrocortisone. Peak expiratory flow rate, forced expiratory volume in 1 second, and forced vital capacity were expressed as a percentage of predicted for each individual and the mean values for each group plotted. It was found that the response rate, as assessed by the area under the curve, was significantly more rapid in group I compared with both group II (P less than 0.001) and group III (P less than 0.005). These findings were consistent for all three lung function measurements. However, there was no significant difference in the responses between group II and group III. It is concluded that adding ipratropium bromide to conventional regimens is likely to benefit patients with acute asthma.

Acute Disease↗
PubMed1993

Continuous intercostal nerve block versus epidural morphine for postthoracotomy analgesia.

Twenty patients undergoing elective thoracotomy were randomized into two groups, receiving either lumbar epidural morphine (n = 10) or continuous extrapleural intercostal nerve block (n = 10). Subjective pain relief was assessed on a linear visual analogue scale. Pulmonary function (peak expiratory flow rate, forced expiratory volume in 1 second, and forced vital capacity) was measured on the day before operation and daily for 4 days after operation. Pulse oximetry monitoring was used to determine the incidence of hypoxemia. No significant difference was observed between the groups concerning pain relief (except at 28 hours, in favor of the intercostal nerve block group), respiratory performance, or arterial oxygen saturation. Vomiting, pruritus, and urinary retention occurred only in the epidural group, whereas nausea occurred significantly less frequently in the extrapleural group. We conclude that after thoracotomy continuous extrapleural intercostal nerve block is as effective as lumbar epidural morphine in reducing postoperative pain and restoring pulmonary mechanics. Because of the significantly lower complication rates we favor continuous extrapleural intercostal nerve block for postthoracotomy analgesia.

Adult↗
PubMed2003

Clinical trial efficacy: what does it really tell you?

The primary goal of most clinical trials is an evaluation of the efficacy of the drug being evaluated. Therefore, it is important to understand if study outcomes are a true reflection of a drug's "real-life" effectiveness. Clinical trials generally evaluate three types of outcomes: subjective, objective, and health-related. Clinical trials that use subjective measures as endpoints usually evaluate outcomes such as symptom scores, the need for rescue medication, and quality-of-life measures. The majority of clinical trials rely on objective measures to test the efficacy of asthma medications. These include lung function (peak expiratory flow rate, forced expiratory volume at one second [FEV1]), level of bronchial hyperresponsiveness (methacholine challenge or exercise challenge), and markers of inflammation (exhaled nitric oxide, sputum eosinophils, bronchoalveolar lavage, and bronchial biopsy). FEV1 remains the gold standard of efficacy measures; however, in pediatrics, where FEV1 values are often within the normal range, re-adjustment of what constitutes various levels of asthma severity should occur. Occasionally, studies will include an assessment of health outcomes, either as a primary or secondary measure, during the course of the study. Commonly measured health outcomes include a reduction in need for rescue systemic glucocorticoids, a reduction in the need for emergent asthma care, a reduction in asthma hospitalizations, and a reduction in asthma deaths. Studies designed to assess impact of treatment regimens on morbidity and mortality remain a high priority, as do studies designed to predict response to current asthma therapies.

Anti-Asthmatic Agents↗
PubMed1999

Minimal access surgery for cholelithiasis induces an attenuated acute phase response.

BACKGROUND: Some benefits of laparoscopic (LC) and minilaparotomy (MC) cholecystectomy may reflect attenuation of the acute phase response. The authors examined components of this response. METHODS: Patients were randomized to LC (n = 11) or MC (n = 11). C-reactive protein (CRP), alpha-1-antitrypsin (AAT), retinol-binding protein (RBP), transferrin, and albumin were measured preoperatively and on postoperative days 1, 2, 4, and 7. Interleukin-1 receptor antagonist (IL-1ra), IL-6, and tumor necrosis factor (TNF-alpha) were measured more frequently perioperatively. Peak expiratory flow rate, forced expiratory volume in 1 second, and forced vital capacity were measured daily. RESULTS: The IL-6 increase was more persistent and marked in the MC patients from hour 8 to day 7 postoperatively (P < 0.05). Alterations in CRP, AAT, and albumin were similar. Postoperative deficits of respiratory function correlated with the magnitude of acute phase protein alteration. CONCLUSIONS: Minimal access surgery induces an acute phase response that is less prominent after a laparoscopic technique.

Acute-Phase Proteins↗