Variability of peak flow in wheezy children.

Johnston, I. D. A.; Anderson, H R; Patel, Shaily

doi:10.1136/thx.39.8.583

Cited by 23 publications

(9 citation statements)

References 22 publications

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“…Children who were wheeze-free at follow-up tended to cough in the mornings, whereas those with current wheeze coughed throughout the night, particularly in the early part of the night. This is similar to the observation of THOMSON et al [24] who found that the timing of night cough in asthmatic children varied during the night and was out of phase with the nadir in peak flow [9]. There is no published information on the precise timing of cough during the night in various respiratory disorders in which cough, is prominent.…”

Section: Night Cough and Current Wheeze Statussupporting

confidence: 61%

“…Eur Respir J., 1996, 9, 65- [7]. This work has shown that these cyclical phenomena reach a bathysphase (lowest point) during the night [7][8][9][10]. The timing of nocturnal cough does not tally with the bathysphase of these same measures, possibly indicating an imprecise relationship between cough and other measures of asthma severity.…”

mentioning

confidence: 99%

“…Putative explanations relate to circadian phenomena, such as increased bronchial responsiveness [4], increased airway lability [5], increased sensitivity to inhaled allergens [6], autonomic imbalance [7], and decreased airway calibre [8]. Circadian rhythms have been demonstrated for peak expiratory flow rate [9], bronchial responsiveness [10], and catecholamine secretion [7]. This work has shown that these cyclical phenomena reach a bathysphase (lowest point) during the night [7][8][9][10].…”

mentioning

confidence: 99%

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Night cough in a population-based sample of children: characteristics, relation to symptoms and associations with measures of asthma severity

Brooke

Lambert²,

Burton³

et al. 1996

Eur Respir J

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Nocturnal cough in asthma is a common but poorly understood phenomenon. The aims of this study were to determine the relationship between recorded night cough, reported night cough and current wheeze in a population-based sample of children previously identified as wheezy, and to examine the relationship of nocturnal cough to current symptoms, markers of asthma severity and environmental exposure.Children were reassessed in the early school years by measuring current symptoms, ventilatory function, bronchial reactivity, peak flow variability, respiratory symptom diaries and home monitoring of overnight cough, transcutaneous arterial oxygen saturation, room temperature and humidity. Night studies were performed on 59 asymptomatic children and 41 children with current wheeze.Cough occurred more frequently in current wheezers compared to asymptomatic children (16 out of 41 (39%) vs 11 out of 59 (19%)), and more cough episodes were recorded (median 3.5 vs 2.0). Night cough was not associated with bronchial reactivity, peak flow variability, degree of morning dip, mean overnight arterial oxygen saturation, ventilatory function, maternal smoking or treatment of asthma. However, it was associated with lower overnight air temperature.Although night cough is more common in current wheezers, there is poor agreement between recorded and reported night cough. Objective tests of asthma severity are of little use in predicting its presence in this age group. The sleeping environment deserves further study. Eur Respir J., 1996, 9, 65- [7]. This work has shown that these cyclical phenomena reach a bathysphase (lowest point) during the night [7][8][9][10]. The timing of nocturnal cough does not tally with the bathysphase of these same measures, possibly indicating an imprecise relationship between cough and other measures of asthma severity. Clarification of the precise relationships between nocturnal cough and measures of respiratory function are further hampered by the poor reporting of nocturnal cough, particularly in children [11,12]. In addition, most reported studies have concerned children with severe asthma and/or asthmatics undergoing therapeutic trials to reduce night cough [13]. Finally, it has been recognized that the analysis of factors important in determining night cough may be confounded by environmental exposures, such as tobacco smoke [14], pollutants [15] and dampness [16].We have studied night cough in a population-based cohort of children aged 4-7 yrs, who had previously been identified as having wheeze in the preschool years, with the following aims: 1) to determine the relationship between recorded night cough and recent wheeze (within the last year); 2) to compare the reported frequency of night cough with that actually recorded at night; 3) to define the nature and timing of nocturnal cough in those with and without wheeze in the preceding year; and 4) to determine whether factors, such as lung function, bronchial reactivity and environmental exposure, predict, or are associated with, nocturna...

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Section: Night Cough and Current Wheeze Statussupporting

confidence: 61%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Night cough in a population-based sample of children: characteristics, relation to symptoms and associations with measures of asthma severity

Brooke

Lambert²,

Burton³

et al. 1996

Eur Respir J

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“…On this basis, the in strument A seems to be preferable for single and for serial PEFR measurements, where the assessment of variability is cru cial [5,6]. However, the performance of A with respect to PEFR variability is satis factory only in a reduced range of air flows.…”

Section: Discussionmentioning

confidence: 99%

“…These measurements are usually done, in the outpatients, using mini peak flow meters, which are very dif ferent between manufacturers. Studies in vestigating the accuracy of some dispos able instruments have been published [4], Several methods have been proposed to evaluate the PEFR diurnal variability [5,6] but the performance of the instruments to reproduce the actual variability of PEFR has not been investigated so far.…”

Section: Introductionmentioning

confidence: 99%

Comparison of The Performance of Two Mini Peak Flow Meters

Pistelli

Fuso²,

Muzzolon³

et al. 1989

Respiration

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Two mini peak flow meters commonly used to monitorize the peak expiratory flow rate (PEFR) are compared to assess their agreement, precision and, with respect to a standard pneumotachygraph, accuracy. Precision of the mini-Wright peak flow meter is greater, possibly as result of a systematic overestimation of PEFR values. The Assess peak-flow meter is more accurate, but its ability to reproduce the actual well-known PEFR variability is dependent from the absolute level of air flow. The agreement between two instruments is very poor, both in asthmatics and in normals, so that it is mandatory to use always the same mini peak flow meter in population studies and during the follow-up of asthmatic patients.

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Hydrolytic stabilities of some polyurethane hydrogels

Lai¹

1991

J of Applied Polymer Sci

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SYNOPSISThe hydrolytic stability of some polyurethane hydrogels derived from UV-curable urethane prepolymers and hydrophilic monomers was addressed. It was found that polyurethane hydrogels derived from prepolymers with hydrophilic polypropylene glycol soft segments were not stable when the films were cast from nonpolar solvent, whereas they are stable if the films were cast from neat monomer mix. The causes for this instability were analyzed. Spectroscopic and gel permeation chromatographic studies of the water extractables suggested that improper curing of hydrophilic monomers with the urethane prepolymers in nonpolar solvent was mainly responsible for the instability phenomenon. I N T R O D U CTlO NPolyurethanes have broad applicability because their properties can be tailored by variation of their components: the flexible polyol, short chain diol, and polyisocyanates. Urethane polymers are used extensively as foams, coatings, adhesives, elastomers, and fibers.' Polyurethanes are widely used as biomedical materials and rapid growth is expected as scientists and manufacturers are capable of tailoring the basic polyurethane products to suit their intended applications.2 Polyurethane hydrogels were claimed to have applications in the biomedical area. Blair and Hudgin disclosed the use of hydrophilic polyurethanes as a soft contact lens material.3 Gould and Johnston reported the interpenetrating polymer networks of polyurethane and acrylates by polymerizing diacrylates in the presence of a hydrophilic polyurethane.4-7 These systems formed hydrogels and were claimed to have applications as contact lenses, surgical implants,8 canulae,' and separation membranes."One of the most critical requirements for hydrogels to be useful as durable devices is their hydrolytic stability. Not all hydrogels are hydrolytically stable. Recently, in an evaluation of some polyurethane hydrogels for biomedical applications," we found that some hydrogels were not hydrolytically stable.

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Variability of peak flow in wheezy children.

Cited by 23 publications

References 22 publications

Night cough in a population-based sample of children: characteristics, relation to symptoms and associations with measures of asthma severity

Night cough in a population-based sample of children: characteristics, relation to symptoms and associations with measures of asthma severity

Comparison of The Performance of Two Mini Peak Flow Meters

Hydrolytic stabilities of some polyurethane hydrogels

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