Higher Peak Expiratory Flow Research Articles

Increased adhesion to vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 of eosinophils from patients with asthma

Adhesion of peripheral blood eosinophil and neutrophil granulocytes to the endothelial cell adherence receptors E-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 has been measured. The study included patients with allergic rhinitis, patients with mild allergic and nonallergic asthma, and healthy individuals; 10 persons were in each group. In addition, assay of eosinophil and neutrophil cell surface expression of the receptor complex CD11b/CD18 was performed. Increased eosinophil adhesion to vascular cell adhesion molecule-1 ( p < 0.05) and intercellular adhesion molecule-1 ( p < 0.05) was demonstrated in the patients with a more labile asthma, that is, a peak expiratory flow rate variability of more than 10%, suggesting a relationship to the degree of ongoing inflammation in the airways of the patients. The increased eosinophil adhesion was most probably due to a functional upregulation of the CD11b/CD18 and very late activation antigen-4 receptors, because the number of receptors measured as cell surface expression was unaltered. The increased eosinophil adhesion in the patients with high peak expiratory flow rate variability appeared independent of atopy. The increased adhesion was not entirely specific to the eosinophils, because neutrophils from patients with a peak expiratory flow rate variability of more than 10% also demonstrated increased adhesion to intercellular adhesion molecule-1 ( p < 0.05) when compared with neutrophils from the patients with low peak expiratory flow rate variability. In conclusion, the demonstrated priming of eosinophil adhesion to vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 might be one contributing mechanism behind the selective accumulation of eosinophils in the lung tissue of patients with asthma. (J A LLERGY C LIN I MMUNOL 1995;96:941-50.)

Tidal breathing flow-volume loops in horses with recurrent airway obstruction (heaves)

Summary Tidal breathing flow-volume (tbfv) loops were determined in a group of control horses and in horses affected with recurrent airway obstruction (heaves). The latter group was studied when the condition was in remission and under increasing amounts of airway obstruction as reflected by measurements of change in pleural pressure, pulmonary resistance, and dynamic compliance. The tbfv loops of control horses had biphasic inspiratory and expiratory patterns; peak inspiratory and peak expiratory flows were detected early in inspiration and expiration, respectively. Tidal volume was unaffected by heaves, but at all stages of heaves, respiratory frequency was increased principally because of shorter inspiratory time, and therefore, inspiratory flow rate was increased. In horses with heaves, tbfv loops did not have a biphasic pattern; peak inspiratory flow was observed late in inspiration, and peak expiratory flow was observed early in expiration. As airway obstruction became more severe, peak expiratory flow increased as pulmonary resistance increased so that, during severe airway obstruction, tbfv loops had a characteristic appearance with high peak expiratory flow early in expiration followed by low flow rate.

Peak expiratory flow variability and bronchial responsiveness to methacholine. An epidemiologic study in 117 workers.

We studied the relationships between peak expiratory flow (PEF) variability and bronchial responsiveness to methacholine in 117 workers attending the annual compulsory examination (mean age, 38.7 yr +/- 9.5; men, 86.3%). Subjects recorded their highest PEF out of three, every 3 waking hours (i.e., five times a day) for 7 days, each using a newly purchased Vitalograph peak flow meter, and underwent methacholine challenge tests with a maximal cumulative dose of 1,200 micrograms. Those with a FEV1 fall of 15% or more were considered as reactors. The variability of PEF was expressed as the amplitude percent mean, calculated from daily amplitude (highest-lowest reading/mean reading of the day x 100), averaged over 6 days, from the second to the seventh. This index had a continuous distribution, skewed towards the greatest amplitudes, and correlated negatively with FEV1 (r = -0.25, p = 0.01). Subjects with asthma (n = 8) had greater variations. In the 109 nonasthmatics, greater variability was observed in subjects with wheeze apart from colds, breathlessness, or hay fever; the average amplitude was greater in reactors than in nonreactors to methacholine (16.9% versus 9.3%, p less than 0.001). The subjects with excessive PEF variability were all methacholine reactors, but they were only a subgroup of the reactors. These results provide evidence that excessive PEF variability is an indicator of bronchial hyperresponsiveness to methacholine in a population sample.

Formoterol, a new long acting beta 2 agonist for inhalation twice daily, compared with salbutamol in the treatment of asthma.

Sixteen patients with stable chronic asthma participated in a double blind crossover study comparing the new inhaled long acting beta 2 agonist formoterol with salbutamol. Inhaled (n = 15) and oral steroid (n = 1) treatment were maintained at the same daily dose throughout the study. For four weeks the patients received either formoterol 24 micrograms twice daily or salbutamol 400 micrograms twice daily, plus additional puffs (with the same drug) when needed. Asthma symptoms, additional puffs of beta 2 agonist, peak expiratory flow (PEF), and side effects were recorded daily. During treatment with formoterol the patients used fewer additional puffs of beta 2 agonist, had better symptom scores, less disturbed sleep, more days without additional aerosol, and higher PEF both morning and evening than during salbutamol treatment. Thus formoterol 24 micrograms twice daily gave long lasting bronchodilatation and asthma symptoms were well controlled with regular twice daily administration.

Lung function in teenage Bangladeshi boys and girls

Data on forced vital capacity, forced expiratory volume in one second and peak expiratory flow rate were obtained in a group of 588 healthy and well-nourished (but not obese) Bangladeshi teenagers to establish normal values in this population. Bangladeshi girls in their early teens showed higher peak expiratory flow rates than boys of the same age but while this continued to rise in boys after the age of 15 years the peak expiratory flow rate in girls seemed to have attained its maximum values by that age. Correlations between sitting height and the lung function variables were found to be marginally greater than those with standing height. Prediction equations were calculated for each lung function variable with sitting and standing separately. Comparison of the results in our study with those reported from other ethnic groups indicate that Bangladeshi values are lower than those of Europeans, Jordanians or Chinese but not significantly different from those reported for Libyans. Since in practice, genetic, nutritional and environmental factors are not readily disentangled, norms for a given study population need to be derived from healthy subjects of similar background and ethnicity.

Points: Falsely high peak expiratory flow readings

Points: Falsely high peak expiratory flow readings