Smoking cessation for parents of children with asthma.
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Adult↗
Biomedical subjects
M A Wall
Publications and source records attributed to M A Wall.
Communication between the PC and laboratory instruments.
In this paper we describe communications between a personal computer and any instrument with a serial port for the purpose of collecting data or controlling equipment and a program for performing this task. From a user-defined file, the software reads the communication parameters: baud rate, data bits, stop bits and parity. The communication protocol is also read: echo, acknowledge and end-of-transmission characters. The software can be used to determine the protocol, to check the integrity of the communications, and can form the basis of a program for more specific applications.
Equipment and Supplies↗
Respiratory impedance and multibreath N2 washout in healthy, asthmatic, and cystic fibrosis subjects.
We measured forced expiratory volume in 1 s (FEV1), respiratory impedance (Zrs) from 4 to 60 Hz, and a multibreath N2 washout (MBNW) in 6 normal, 10 asthmatic, and 5 cystic fibrosis (CF) subjects. The MBNW were characterized by the mean dilution number (MDN) derived by a moment analysis. The Zrs spectra were characterized by the minimum resistance (Rmin), the drop in resistance (Rdrop) from 4 Hz to Rmin, and the first resonance frequency (Fr1). Measurements were repeated after bronchodilation in three normal and all asthmatic subjects. Before bronchodilation, six of the asthmatic subjects showed close to normal FEV1. The Zrs in the normal subjects showed low Rmin (1.9 +/- 0.7 cmH2O.l-1.s), Rdrop (0.4 +/- 0.4), and Fr1 (10 +/- 2 Hz). Four of the mildly obstructed asthmatic subjects had normal Zrs but elevated MDNs (i.e., abnormal ventilation distribution). The other six asthmatic subjects had significantly elevated Rmin (4.1 +/- 0.8), Rdrop (6.3 +/- 5.8), and Fr1 (34 +/- 0.4 Hz) and elevated MDNs. The CF patients had elevated Zrs features and MDNs. After bronchodilation, no changes in FEV1, MDN, or Zrs occurred in the normal subjects. All asthmatic subjects showed increased FEV1 and decreased MDN, but the Zrs was unaltered in the four asthmatic subjects whose base-line Zrs was normal. For the other six asthmatic subjects, there were large decreases in the Rmin, Rdrop, and Fr1. Finally, there was a poor correlation between the MDN and the Zrs features but high correlation between the Zrs features alone. These results imply that significant nonuniform peripheral airway obstruction can exist such that ventilation distribution is abnormal but Zrs from 4 to 60 Hz is not. Abnormalities in Zrs from 4 to 60 Hz occur only after significant overall obstruction in the peripheral and more central airways. Combining Zrs and the MBNW may permit us to infer whether the disease is predominantly in the lung periphery or in the more central airways.
Adolescent↗
Changes in ventilation homogeneity from preschool through young adulthood as determined by moment analysis of nitrogen washout.
This study was designed to assess potential differences in ventilation homogeneity related to growth. One hundred thirty-three healthy subjects representing four stages of growth were studied: group 1, preschool, ages 34-74 months; group 2, preadolescent, ages 8-10 yr; group 3, postpubertal, ages 15-17 yr; group 4, young adult, ages 26-40 yr. Ventilation homogeneity was assessed by moment analysis of multibreath nitrogen washout with functional residual capacity, the ratio of the 1st to 0th moment (MR 1/0), and the ratio of the 2nd to 0th moment (MR 2/0) being the outcome variables of interest. Across the four groups functional residual capacity increased as a curvilinear function of height. At all heights functional residual capacity was larger in males than females and the slope of the regression was steeper in males than females (p less than 0.001). Both MRs 1/0 and 2/0 were significantly higher in group 1 than the other groups, indicating that ventilation washout was less homogeneous in the preschool subjects than in older children or adults. Males of group 1 had significantly higher values for both moment ratios (more ventilation nonuniformity) than females. In the other groups there were no significant sex based differences although there was a trend for males to have a lower MR 1/0 than females in the young adults, p = 0.08. The results indicate that both age and sex are important determinants of the growth of distribution of ventilation.
Adolescent↗
Cotinine in the serum, saliva, and urine of nonsmokers, passive smokers, and active smokers.
Cotinine was measured in the serum, saliva, and urine of nonsmokers, passive smokers, and active smokers. Serum and saliva could not discriminate between nonsmokers and passive smokers. Mean urine cotinine was higher in passive smokers than nonsmokers but there was a great deal of intersubject overlap. Cotinine in all body fluids could separate active smokers from the other two groups. Among smokers, light smokers had lower levels than heavier smokers.
Adult↗
Relationship between maldistribution of ventilation and airways obstruction in children with asthma.
This study was designed to explore the relationship between ventilation non-uniformity, as assessed by moment analysis of nitrogen washout, and airways obstruction, as assessed by spirometry, in children with asthma. Moment ratios derived from the multibreath washout curves in asthmatics were significantly higher than those obtained from healthy controls (P less than 0.001). Among patients with asthma, moment ratios showed a high degree of negative correlations with spirometric variables expressed as percent of predicted, i.e., increasing airways obstruction was associated with increasing ventilation non-uniformity. When the subjects were tested on multiple occasions during one test day the results demonstrated a strong quantitative relationship within subjects between spontaneous changes in moment ratios and spirometric variables (P less than 0.001), with the slope of the regressions showing a trend to vary from one patient to another. Chi squared analysis showed that significant changes in FEV1 were paralleled by corresponding significant changes in moment ratios with a sensitivity of approximately 81% and a specificity of 82%. Additionally, changes in FEV1 induced by an inhaled bronchodilator were associated with concomitant changes in moment ratios. We conclude that: (1) the majority of children with asthma have some degree of ventilation non-uniformity which is correlated with their degree of airways obstruction, and (2) spontaneous changes in airways obstruction in such subjects are paralleled by changes in ventilation non-uniformity.
Adolescent↗
Pulmonary function testing in children.
This article concentrates on those factors that are particularly important for performing and interpreting lung function tests in children. Specifically, technical considerations such as equipment, personnel, test performance, and bronchoprovocation procedures are discussed. Changes in lung function with growth and appropriate use of race-specific reference standards are emphasized, and references for standard and experimental pulmonary function tests are provided. Several examples illustrating the utility of pulmonary function testing in clinical situations in children with lung disease are provided as well.
Blood Gas Analysis↗
Moment analysis of multibreath nitrogen washout in young children.
The purpose of this study was to determine whether on-line computerized moment analysis of multibreath N2 washout (MBNW) could be used as a method of estimating lung function in children too young to cooperate with routine pulmonary function testing. The limits of normal variability were determined from results obtained from duplicate studies performed on 36 healthy children ages 3-6 yr. Five healthy adults were studied for comparison. Test sensitivity was estimated by comparing the results in the healthy group to those of 10 age-matched children with cystic fibrosis (CF). Outcome variables of interest included functional residual capacity, the first-to-zeroth moment ratio (M1/M0), the second-to-zeroth moment ratio (M2/M0), and the lung clearance index. Test precision in the healthy group was high with the intrasubject coefficient of variation for all variables being less than 10%. There was no difference in mean within- or among-subject variability between the healthy children and the older, theoretically more cooperative, healthy adults. Mean M1/M0 and M2/M0 were both higher in CF than in the healthy group, 2.69 vs. 2.32 and 13.04 vs. 9.31, respectively (P less than 0.001). Moment ratios in CF showed good negative correlations with Shwachman scores; thus those CF patients with the most advanced lung disease had the highest moment ratios and vice versa. Moment analysis of MBNW has promise as a means of quantifying lung function in young children, since the method is noninvasive, low in inherent variability, requires only quiet breathing, and has the sensitivity required to detect rather mild ventilation inhomogeneity.
Child↗
Lung function in children with sickle cell anemia.
Lung volumes and expiratory flows were measured in 12 children with sickle cell anemia and 12 height-matched black control subjects. Diffusing capacity of the lung for CO, pulmonary capillary blood volume, the membrane component of diffusing capacity, arterial blood gases on breathing room air and 100 per cent O2 were measured in the subjects with sickle cell anemia. The lung volumes and expiratory flows of subjects with sickle cell anemia were no different from those of the control subjects. Diffusing capacity for CO was maintined in the noraml range despite the severe anemia by increases in pulmonary capillary blood volume and the membrane component of diffusing capacity. All subjects with sickle cell anemia had mild hypoxemia and abnormal increases in calculated shunt. Pulmonary function in children with sickle cell anemia appears to be determined by their race and anemia.
Adolescent↗
Lung function in adolescents receiving high-dose methotrexate.
Methotrexate (MTX) has been implicated as a cause of interstitial pneumonitis and/or fibrosis, but the mechanism by which the drug causes these processes is not known. The purpose of this study was to determine whether patients receiving high-dose MTX developed a consistent decrease in pulmonary function, which would implicate a role for total dose of MTX received in the pathogenesis of the lung toxicity. Pulmonary function studies, including spirometry, plethysmography, and diffusing capacity at two levels of alveolar PO2, were performed in 38 adolescents treated for osteogenic sarcoma. The patients were divided into three groups including 12 patients (group 1) studied before and during therapy, 15 patients (group 2) studied during therapy, and 11 patients (group 3) studied after completion of treatment. While total dose received at the time of the study varied from 0 to 256 gm/sq m, pulmonary function showed no change, with one exception. A mild restrictive defect and decrease in diffusing capacity due to unilateral pleural and diaphragmatic disease, whose relationship to MTX therapy is uncertain, developed in one patient. MTX, when administered in high dose to young patients by the described protocol, causes no dose-related decrease in pulmonary function.
Adolescent↗
Etiology of pneumonitis in children with leukemia.
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Leukemia, Lymphoid↗
Implementation of "Open Airways" as an educational intervention for children with asthma in an HMO.
This article describes the adaptation and implementation of an existing pediatric asthma-management educational program, Open Airways, for members of a large group practice health maintenance organization. Seventy-four children ages 4 to 14 years and their families were randomized into one of seven class cohorts as part of a larger study of pediatric asthma management. The Open Airways program was modified to increase the emphasis on behavioral change and medication information and to reflect the different sociodemographic makeup of the population, compared with that for which the program was developed. Of the 74 families, 62 attended at least one class, and 47 of these attended five or more classes. Evaluations after classes suggest an increase in parental confidence in managing their child's asthma and an earlier use of medications. Health care providers may be able to adapt similar programs for successful use with their populations.
Adolescent↗