Fall In Peak Expiratory Flow Rate Research Articles

A quasi-experimental study of the effects of yogic practices on pulmonary functions and exercise-induced bronchial lability in children with controlled asthma

Background: It has been observed that regular practice of yogic postures (asana) and breathing exercises (pranayama) improves the airway dynamics of healthy persons. This can be helpful for reducing exercise-induced bronchial lability, and thus yoga and pranayama could be used as an effective management strategy for asthma. Objectives: The objective was to study the effect of 12 weeks of regular yogic practices on pulmonary functions and exercise-induced bronchial lability in asthmatic and healthy children. Objectives: The objective was to study the effect of 12 weeks of regular yogic practices on pulmonary functions and exercise-induced bronchial lability in asthmatic and healthy children. Materials and Methods: Thirty asthmatic children attending pediatrics outpatient department were enrolled as cases (Group I) and thirty apparently healthy children who were having no any family history of asthma were enrolled as controls (Group II). Both the groups were further divided into four subgroups namely Ia, Ib, IIa, and IIb (Groups Ia and IIa – not practicing yoga and Groups Ib and IIb – practicing yoga). The yoga groups (Ib and IIb) performed yoga regularly for 45 min daily for 12 weeks under the guidance of a yoga expert. Spirometry (lung volume and capacities as well as flow rates) along with exercise-induced bronchial lability testing was done at baseline and at 12 weeks in all participants. The responses to exercise were quantitated as the percentage rise and fall in the peak expiratory flow rate (PEFR) during and after exercise and Exercise Lability Index (ELI). Results: Group Ib (asthmatics, practicing yoga) had significant increases in vital capacity (VC), forced VC (FVC), forced expiratory volume in 1 s (FEV1%), and PEFR and a decrease in percentage fall in PEFR and ELI at 12 weeks. Group IIb (healthy, practicing yoga) had highly significant increases in VC, FVC, and FEV1 and a significant increase in PEFR and a decrease in ELI at 12 weeks. Conclusions: By improving pulmonary functions and reducing exercise-induced bronchial lability, yoga helps asthmatics as well as healthy children to cope better with vigorous physical activities.

Sensitivity of peak expiratory flow rate for diagnosing bronchial obstruction on methacholine inhalation challenge in school-aged asthmatic children

To study whether forced expiratory volume in 1 s (FEV1) for the diagnosis of bronchial reactivity by means of the methacholine inhalation challenge test could be appropriately replaced by simple measurements of peak expiratory flow rate (PEFR), 75 consecutively referred asthmatic children aged 6–15 y were examined during a symptom-free period. Their baseline FEV1 and PEFR values ranged from 70 to 130% (mean 99.1) and from 77 to 122% (mean 101.4) of those predicted, respectively. The methacholine inhalation challenge was performed with stepwise doubled cumulative doses and both FEV1 and PEFR were measured at each step. Of the 67 children who had a 20% reduction in either test, the fall in FEV1 was achieved after a lower dose of methacholine than the 20% fall in PEFR in 49 cases, after a higher dose in 15 and after the same dose in 3. There was a significant correlation (r= 0:56, p < 0:001) between the changes in FEV1 and PEFR, although considerable scatter was found in the results. The 64 children who had a reduction of 20% in FEV1 showed a corresponding drop in PEFR that varied from 1.8 to 28.8% (mean 15.3), including 9 children for whom this drop was less than 10%. The results indicate that if the challenge test were based on PEFR measurements, the reference values for the test would have to be different.

Nitrogen dioxide exposure from domestic gas cooking and airway response in asthmatic women.

Previous studies have not found a consistent association between exposure to domestic cooking using gas appliances and exacerbation of asthma. We investigated the immediate airflow response to acute exposure from single episodes of gas cooking, and peak airflow variability from continued exposure to repeated episodes of gas cooking in a group of non-smoking asthmatic women. Sixteen adult non-smoking women with mild to severe persistent asthma were studied. The acute short term level of nitrogen dioxide (NO2) during gas cooking episodes and the mean exposure to NO2 from repeated gas cooking episodes were measured over a 2 week period, as well as proxy measures of frequency of cooking on each day and the length of time spent cooking each day. Their asthma status was monitored using peak expiratory flow rates (PEFR) before and after cooking, 2 week self-recorded serial readings of PEFR, respiratory symptom severity score, and use of rescue bronchodilators for acute asthma attacks. Cooking was significantly associated with an immediate mean fall in PEFR of 3.4% (p=0.015, paired t test). The acute short term NO2 level during cooking was significantly correlated with the fall in PEFR (r=-0.579; p=0.019). The frequency of cooking over a 2 week period was positively correlated with the mean exposure to NO2 (r=0.529; p=0.042). Continued exposure to NO2 over a 2 week period was associated significantly with increased frequency of rescue bronchodilator usage for asthma attacks (r=0.597; p=0.031). However, it was negatively associated with PEFR variability (r=-0.512; p=0.051) and respiratory symptom severity score (r= -0.567; p=0.043), probably due to the masking effects of bronchodilator treatment. Acute short term exposure to NO2 from single episodes of gas cooking is associated with immediate airflow limitation. Continued exposure from repeated episodes of gas cooking in asthmatic women is associated with greater use of rescue bronchodilators.

Nitrogen dioxide exposure from domestic gas cooking and airway response in asthmatic women

BACKGROUNDPrevious studies have not found a consistent association between exposure to domestic cooking using gas appliances and exacerbation of asthma. We investigated the immediate airflow response to acute exposure from...

Exhaled carbon monoxide levels during treatment of acute asthma.

Carbon monoxide is known to be present in measurable quantities in the exhaled air of normal subjects and at higher concentrations in asthmatic patients not treated with glucocorticoids. To examine whether exhaled CO is useful in monitoring asthma control, time course changes in peak expiratory flow rate (PEFR) and exhaled CO concentration before and after treatment of acute asthma exacerbations were measured in 20 asthmatic patients. Exhaled CO was measured in triplicate by a portable CO analyser. Exhaled CO was reproducible at all time points. Asthma exacerbations caused a fall in PEFR and a rise in exhaled CO (towards an average of 3.3 parts per million (ppm)) in all patients, and treatment with oral glucocorticoids reversed these changes in both parameters. An improvement of PEFR was closely associated with a reduction of exhaled CO (to an average of 1.5 ppm) after treatment. The maximal exhaled CO concentration significantly correlated with recovery time of PEFR after treatment with oral glucocorticoids (p<0.01). The present study suggests that exhaled CO may be a useful noninvasive means of monitoring the control of asthma.

Acute changes in peak expiratory flow rate following palliative radiotherapy for bronchial carcinoma

Purpose: Changes in respiratory function occurring in the months and years following radiotherapy have been well documented. The changes that occur in the hours after treatment are less clear, we report a study that recorded peak expiratory flow rate (PEFR) in the 72 h following radiotherapy to the mediastinum and large airways. Methods: Fifty-six patients with carcinoma affecting the major bronchii were recruited; 39 were male, with a median age of 66 years; 49 had histologically confirmed lung cancer. The median baseline PEFR was 300 l/s (range: 120–600). Patients were asked to record home PEFR readings in the 72 h that followed the first fraction of radiotherapy. Doses ranges from an 8-Gy single fraction to 60 Gy in 30 fractions. Results: Forty-nine patients recorded a fall in PEFR (3%–60% of the baseline value) in the 24 h after radiotherapy, the mean for all 56 patients was a fall of 20.3% (95% confidence interval −15.8% to −24.8%). These lowest values occurred a median time of 6 h after treatment (range: 2–24 h). By 72 h the mean PEFR had returned to the baseline. Tumour site (central or lobar bronchus) and fraction size (<3 GY or > 3 Gy) had no significant effect on the fall in PEFR (Mann-Whitney U-test P = 0.15 and P = 0.06, respectively). Conclusion: We conclude that a fall in PEFR can occur after radiotherapy treatment to the mediastinum. This is of concern in patients being treated for bronchial carcinoma whose respiratory function may already be compromised.

Exercise induced bronchospasm in Ghana: differences in prevalence between urban and rural schoolchildren.

BACKGROUND: As more developing countries adopt a westernised style of living, an increase in the prevalence of asthma can be expected to occur in these areas. A study was undertaken...

Safety of fibreoptic bronchoscopy in asthmatic and control subjects and effect on asthma control over two weeks.

Concerns remain about the safety of bronchoscopy in asthma and there are few data on the effect of this procedure on asthma control in the days or weeks following bronchoscopy. In an initial study of bronchoalveolar lavage and bronchial biopsies in asthmatic and control subjects, data on peak expiratory flow rates (PEFR) collected prospectively before and after the procedure were available from 21 of the 29 asthmatic subjects studied. These showed a median 23% fall in PEFR from baseline after bronchoscopy (range 3-58%). To determine whether this fall in PEFR following bronchoscopy reflected bronchospasm or the effect of sedation, PEFR and spirometric tests were performed during the two hours following bronchoscopy in a further study of 15 symptomatic asthmatic subjects and 20 non-asthmatic controls. To examine the effect on asthma control, asthmatic patients recorded PEFR, symptom scores, and medication use for two weeks before and after bronchoscopy. After bronchoscopy with bronchial biopsies there was no difference between the median maximal fall in either PEFR or arterial oxygen saturation between the 15 asthmatic patients (10.4% and 4%, respectively) and 20 controls (12% and 3%). Moreover, there were no significant changes in PEFR, symptom score, or medication use by the asthmatic subjects in the two weeks after bronchoscopy when compared with the two weeks before bronchoscopy. Fibreoptic bronchoscopy is well tolerated in asthmatic subjects. Falls in PEFR in both asthmatic and non-asthmatic subjects after bronchial biopsy may reflect the effects of sedation rather than bronchospasm. Additional bronchoalveolar lavage may cause bronchoconstriction. Careful monitoring is therefore essential. Peak flow monitoring up to two weeks after bronchoscopy with bronchial biopsy revealed no delayed effects on asthma control.

Real and Pseudo Late Asthmatic Reactions after Submaximal Exercise Challenge in Patients with Bronchial Asthma : A New Definition for Late Asthmatic Responses after Exercise Challenge

The late asthmatic reaction after exercise challenge remains a controversial issue. In this study, 21 patients recorded peak expiratory flow rate (PEFR) on two control days without performing exercise. There was no difference between both control days when PEFR at 1 h was compared with baseline PEFR and when PEFR at 4 to 13 hours was compared with baseline PEFR. After analyzing variation coefficients of baseline PEFR on a control day and exercise day, PEFR was not allowed to differ more than 15.3 percent in the same patient when comparing exercise day and control day for the late fall in PEFR in the study. In 17 of 81 patients, a late asthmatic reaction after exercise challenge was present when PEFR fall was ≥20 percent compared with baseline PEFR value. In eight of the 17 patients, a real late asthmatic reaction to exercise challenge was present with a PEFR fall ≥20 percent on at least three successive time points and who had a PEFR fall ≥20 percent compared with corresponding clocktime on a control day. The late asthmatic reaction to exercise challenge is characterized not as a nonspecific epiphenomenon, but as a fall in PEFR of ≥20 percent compared with baseline PEFR value and with corresponding clocktime on a control day on at least three successive time points. Graphic illustration of airway responses following exercises may facilitate the detection of a late asthmatic response.

49 CIRGADIAN PULMONARY RHYTHMS IN ASTHMATIC CHILDREN AFTER WITHDRAWAL OF MEDICATION

Three days after withdrawal of maintenance treatment, peak expiratory flow rate (PEFR) was measured in 38 asthmatic children every four hours during 24 hours on three consecutive days. In all children a circadian rhythm, with a nocturnal fall in PEFR existed. The interindividual amplitude varied from 2 to 65%. Two groups of 9 patients each, were selected from the total study population based on a difference in PEFR values between 16.00 and 04.00 hours of more then 20% or less then 15% on three study days. The remaining children did not fit in both subgroups because the 16.00 and 04.00 hour difference in PEFR values was not persistent. The clinical data of this group, however, were comparable with both subgroups.In the group with a 16.00 - 04.00 hours difference of more then 20% (mean ± SD: 31.5±8.5) both the mean PEFR value and the PEFR value measured at 04.00 hours on day 6 was significantly decreased as compared to the values obtained on day 4. Moreover the amplitude of the PEFR still increased significantly from day 4 to day 6. In the group with 16.00 - 04.00 hours difference of less then 15% (mean ± SD: 6.4 ± 2.7) no increase in amplitude and decrease in mean PEFR values during day 4 and day 6 were observed. With regard to FEV1/FEV1 predicted, PC20 Histamine and skintests no significant differences were observed between both subgroups. In retrospect the group of children with the large amplitude seems to be more inhaled steroid dependent.

Standardization of the severity of exercise‐induced bronchospasm in Japanese children with asthma:‐ A report of the Committee on Standardization of EIB, Japanese Society of Pediatric Allergy‐

AbstractThe correlation between the severity of asthmatic symptoms and of EIB (exercise‐induced bronchospasm) was studied by changes in PEFR (peak expiratory flow rate). This was accomplished by bicycle ergometer exercise of 12.6 kpm/kg of body weight for 6 minutes, or by treadmill exercise of 6km/h, 10% incline for 6 minutes, by children with bronchial asthma in 7 institutions in Japan (both inpatients and outpatients).The incidence of EIB in those using bicycle ergometers was 63.7%, and the clinical severity paralleled the EIB severity closely, showing complete agreement in 71% and almost complete agreement in 94%. The severity of EIB was as follows: no EIB in less than 15%, mild EIB in15–20%, moderate EIB in 21 ‐45%, and severe EIB in over 45%.The incidence of EIB in those using the treadmill was 65.2% and did not correlate as well as with the clinical severity as in those using the bicycle ergometer. The maximum % fall in PEFR of those judged to be EIB positive using the treadmill was more than 25%.We recommend the use of the bicycle ergometer to determine the severity of bronchial asthma in children.

Analysis of antigen-induced changes in pulmonary mechanics in sensitized inbred rats

An inbred line of rats was derived which develop marked and consistent dyspnea following sensitization and then exposure to aerosolized antigen. This pulmonary response was investigated in detail by determining forced pulmonary mechanics to derive respiratory rate, peak expiratory flow rate (PEFR), forced vital capacity (FVC), forced expiratory volume in 0.1 s (FEV0.1), and maximal midexpiratory flow rate (MMFR). Challenging anesthetized rats for 5 min with an aerosol of 3% egg albumin produced minimal change in respiratory rate, a 20% fall in PEFR, a 50% fall in FVC, and a 30% decrease in FEV0.1 and MMFR. The response could be inhibited or reversed by salbutamol (0.5 mg/kg, i.v.) and aminophylline (25 mg/kg, i.v.) administered either before or after challenge. The pulmonary changes are consistent with antigen-induced asthma in the rats. The response shows similarities to human asthma and may provide a relevant experimental model.

Multiple exercise and histamine challenge in asthmatic patients.

We studied the effects of repeated exercise and histamine challenge in asthmatic patients to determine the frequency and degree to which a state of refractoriness was induced by these stimuli. Twenty-nine patients performed three exercise tests, and on a separate day 16 of these patients had three histamine inhalational challenge tests. Forty minutes separated each challenge. Changes in airways resistance were measured using the peak expiratory flow rate (PEFR). The fall in PEFR (expressed as a percentage of the pre-challenge value) was used to quantify the response to challenge. Significant “protection” was defined as a fall in PEFR after a repeated challenge less than 50% of the fall observed on the first challenge. All patients had a fall in PEFR greater than 22% on the first challenge of the day. With repeated exercise 28 out of 29 patients had a fall in PEFR less than that observed on the first test and 12 had significant “protection”. The fall in PEFR after the third exercise challenge was not significantly different to the second challenge and a “plateau” effect was observed. There was no significant difference in the fall in PEFR after the first and second histamine challenge although two of the 16 patients were significantly protected. After the third histamine challenge five of the 16 patients were significantly protected from the effects of the same dose of histamine. The degree to which repeated exercise challenge induces a diminished response is variable. With repeated challenge the response to histamine remains relatively constant in most patients though 30% may be expected to be refractory after a third challenge.

AN EVALUATION OF ORAL HEXOPRENALINE SULPHATE (IPRADOL) IN EXERCISE‐INDUCED ASTHMA

The effect of hexoprenaline sulphate (1 mg) administered orally on the fall in peak expiratory flow rate (PEFR) after exercise was investigated in 20 asthmatic patients. Compared with placebo, the fall in PEFR expressed as a percentage of the resting value (measured immediately before exercise) was less in 16 of the 20 patients in the presence of hexoprenaline sulphate. This consistent amelioration of exercise-induced asthma has not been observed in this laboratory with similar drugs (such as salbutamol and terbutaline). While eight patients were afforded significant protection by the hexoprenaline sulphate, a fall in PEFR after exercise was within the normal range (less than 10% of the resting value) in only four patients.

A Comparison of Oral Theophylline and Oral Salbutamol in Exercise-Induced Asthma

Ten patients with exercise-induced asthma were premedicated with oral salbutamol and oral theophylline on separate occasions before performing a standardised exercise test. Although both agents produced bronchodilatation, reflected by increases in peak expiratory flow rates (PEFR) at rest, they were generally ineffective in preventing an abnormal post-exercise fall in PEFR. Only one patient was afforded protection by salbutamol and another two patients by theophylline.

Bronchial lability in cystic fibrosis.

Abstract. We investigated the airway's response to exercise in cystic fibrosis (CF). Due to the reported high incidence of allergy in CF we tried to demonstrate the well documented post‐exercise bronchospasm of asthma in patients with CF. Subjects ran on a treadmill for 6 minutes at a speed of three miles per hour and a gradient of 15°.For the 12 controls studied, the mean % rise in peak expiratory flow rate (PEFR) during excercise was 4.7% and the mean % fall in PEFR during recovery was 0.7%. For the eight atopic asthmatics studied the mean % rise in PEFR was 12.2% and the mean % fall in PEFR was 33.7%. For the 29 patients with CF, the mean % rise in PEFR was 20.3% and the mean % fall in PEFR was 3.1%. Patients with CF showed no statistically significant post‐exercise constriction compared with the controls, while asthmatic patients showed a post‐exercise % fall in PEFR significantly greater than seen in controls (p&lt;0.001) or in CF patients (p&lt;0.001). No patient with CF showed post‐exercise bronchospasm, nor was there any difference between patients with CF who had positive skin tests to common allergens and those who did not in their pattern of bronchial lability. It is suggested that the general desensitization therapy should not be instituted in patients with CF merely on the basis of positive skin tests, without more stringent criteria such as characteristic seasonal variation in respiratory symptomatology, family history of atopy and positive bronchial inhalation provocation tests.

Nocturnal and morning asthma. Relationship to plasma corticosteroids and response to cortisol infusion.

Nocturnal and early morning breathlessness is a common and important symptom in asthmatic patients. Six patients in whom these symptoms were a major clinical problem have been studied by serial measurements of peak expiratory flow rate (PEFR) and plasma corticosteroids over two 24-hour periods. Although PEFR and plasma corticosteroids are lowest during the night or early morning, preventing the nocturnal fall in plasma corticosteroids by cortisol infusion did not prevent the fall in PEFR in five out of the six patients. The circadian rhythm of corticosteroid secretion does not appear to be the main cause of nocturnal and early morning asthma.

Peak expiratory flow rates before and after exercise in schoolchildren.

Peak expiratory flow rates (PEFR) were measured before and after 6 minutes9 exercise in 12-year-old schoolchildren living in two areas. In boys, but not in girls, the mean initial PEFR was lower in asthmatics than in nonasthmatics. After exercise, children with current asthma tended to show a marked fall in PEFR. Children with a history of wheezing, atopic disease, or a first-degree asthmatic relative showed something of the same tendency, though their responses to exercise largely overlapped those of the control group. The unknown mechanism causing exercise-induced asthma appears to operate also in some subjects who show features related to asthma, but not in the rest of the child population.