The need for standardisation of peak flow charts

Short term effects of rapid maxillary expansion on breathing function assessed with spirometry: A case-control study

BACKGROUND

The aim of this work is to evaluate changes following rapid maxillary expansion (RME) on breathing function in two groups of patients: mouth breathers and nasal breathers.

MATERIALS AND METHODS

Twenty-five oral breather patients (12 male, 13 female, mean age 15.2 ± 1.3), and 25 nasal breather patients (14 male, 11 female, mean age 15.3 ± 1.6) were treated with RME. Breathing function was evaluated by computerized spirometry. Forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), Tiffenau index (FEV1/ FVC ratio, IT%), forced expiratory flow at 25-75% of vital capacity (FEF 25-75%), and Tidal volume (TV) were assessed. Breathing function analysis was performed before RME and 6 and 12 months after RME during follow-up appointments. The Shapiro-Wilk test was used to assess whether data were normally distributed. As data were not normally distributed, Mann-Whitney U and Friedman tests were used to perform comparisons between treatment groups and within group comparisons, respectively.

RESULTS

Oral breathers and nasal breathers showed statistically significant differences in FVC, FEF 25-75%, and TV at T0. They did not present any statistically significant difference in FEV1 and IT% at the same time point.Statistically significant differences were noticed for all indices in the oral breather group after maxillary expansion, while the nasal breather group showed statistically significant differences only in FCV, FEF 25-75%, and TV after treatment.There were no statistically significant differences in all indices 12 months after maxillary expansion between the oral breather and nasal breather groups.

CONCLUSIONS

RME appeared to improve breathing function in both groups. Forced vital capacity (FVC), forced expiratory flow at 25-75% of vital capacity (FEF 25-75), and Tidal volume (TV) reached similar values in both groups after treatment with RME.

Use of Symptoms Scores, Spirometry, and Other Pulmonary Function Testing for Asthma Monitoring

Asthma is a global problem affecting millions of people all over the world. Monitoring of asthma both in children and in adulthood is an indispensable tool for the optimal disease management and for the maintenance of clinical stability. To date, several resources are available to assess the asthma control, first is the monitoring of symptoms, both through periodic follow-up visits and through specific quality of life measures addressed to the patient in first person or to parents. Clinical monitoring is not always sufficient to predict the risk of future exacerbations, which is why further instrumental examinations are available including lung function tests, the assessment of bronchial hyper-reactivity and bronchial inflammation. All these tools may help in quantifying the future risk for each patient and therefore they potentially may change the natural history of asthmatic disease. The monitoring of asthma in children as in adults is certainly linked by many aspects, however the asthmatic child is a future asthmatic adult and it is precisely during childhood and adolescence that we should implement all the efforts and strategies to prevent the progression of the disease and the subsequent impairment of lung function. For these reasons, asthma monitoring plays a crucial role and must be particularly close and careful. In this paper, we evaluate several tools currently available for asthma monitoring, focusing on current recommendations emerging from various guidelines and especially on the differences between the monitoring in pediatric age and adulthood.

Asthma outcomes: pulmonary physiology

BACKGROUND

Outcomes of pulmonary physiology have a central place in asthma clinical research.

OBJECTIVE

At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to provide recommendations on the use of pulmonary function measures as asthma outcomes that should be assessed in a standardized fashion in future asthma clinical trials and studies to allow for cross-study comparisons.

METHODS

Our subcommittee conducted a comprehensive search of PubMed to identify studies that focused on the validation of various airway response tests used in asthma clinical research. The subcommittee classified the instruments as core (to be required in future studies), supplemental (to be used according to study aims and in a standardized fashion), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011.

RESULTS

A list of pulmonary physiology outcomes that applies to both adults and children older than 6 years was created. These outcomes were then categorized into core, supplemental, and emerging. Spirometric outcomes (FEV(1), forced vital capacity, and FEV(1)/forced vital capacity ratio) are proposed as core outcomes for study population characterization, for observational studies, and for prospective clinical trials. Bronchodilator reversibility and prebronchodilator and postbronchodilator FEV(1) also are core outcomes for study population characterization and observational studies.

CONCLUSIONS

The subcommittee considers pulmonary physiology outcomes of central importance in asthma and proposes spirometric outcomes as core outcomes for all future NIH-initiated asthma clinical research.

Impact of graphic format on perception of change in biological data: implications for health monitoring in conditions such as asthma

BACKGROUND

Variation in graphic format can substantially influence interpretation of data. Despite a large body of literature on the optimal design of graphs, little attention has been paid to the format of charts for health monitoring.

AIMS

This study assessed the effect of aspect ratio (x:y ratio) and interconnecting lines on visual identification of change in biological data, such as during asthma exacerbations.

METHODS

Eighty volunteers viewed 72 sets of six consecutive blocks of unidentified biological data, recording if each block of data was increasing, decreasing, or the same as the previous block. Three chart aspect ratios were examined (A, 5.2:1; B, 3.0:1; C, 1.1:1), with or without lines between data points. Datasets from lung function monitoring by asthma patients included a mild/moderate/severe fall ('exacerbation') or no exacerbation. False negative (missing true exacerbations) and false positive (identifying non-existent exacerbations) responses were calculated.

RESULTS

84% of exacerbation blocks were correctly identified. There was a significant interaction between exacerbation severity and aspect ratio (p=0.0048). The most compressed chart (C) had the fewest false negative responses. Moderate falls were missed in 24%, 12%, and 5% of trials on charts A, B, and C, respectively (C vs A: adjusted relative risk 0.19 (95% CI 0.12 to 0.30)). False positive responses were infrequent (A, 2.5%; B, 3.8%; C, 8.3%), increasing slightly if data points were joined with lines (4.3% vs 5.1%, p=0.004) .

CONCLUSIONS

Compressed charts can improve the visual detection of change in biological data by up to 80%. The aspect ratio of charts should be standardised to facilitate clinical pattern recognition.

Physiological differences and similarities in asthma and COPD--based on respiratory function testing

Physiological differences and similarities in asthma and COPD are documented based on respiratory function testing. (1) The airflow reversibility is usually important for the diagnosis of asthma. However, patients with long disease histories may have poor reversibility. The reversibility test in COPD is useful for predicting the treatment response. (2) In some of the stable asthmatic patients without attack, the concave downslope of flow-volume curve is present. In severe COPD, the flow in the second half of the curve is smaller than that of rest-breathing. (3) Inspiratory capacity (IC) is a good estimator of air trapping and of predicting the exercise capacity in COPD or persistent asthma. (4) Peak expiratory flow (PEF) can be an important aid in both diagnosis and monitoring of asthma. PEF is not used in COPD because the main disorder is in the peripheral airway. (5) Measurements of airway responsiveness may help to a diagnosis of asthma. However, many COPD cases also have it. (6) Impulse oscillation system (IOS) revealed that the predominant airway disorders in asthma and COPD are central and peripheral respiratory resistance, respectively. However, some asthma patients have larger values of peripheral component. (7) D(LCO) reflects the extent of pathological emphysema and it is useful for the follow-up of COPD, whereas D(LCO) is not decreased in asthma. (8) The patient with widened A-aDO(2) and alveolar hypoventilation may lead to the life threatening hypoxia in severe asthma attack or severe COPD. When PaCO(2) overcomes PaO(2), the patient should immediately be treated by mechanical ventilation.

Assessment of asthma control and its impact on optimal treatment strategy

Achieving and maintaining optimal asthma control is a major asthma management goal advocated by the Global Initiative for Asthma (GINA). Recent evidence suggests that while asthma control is clearly achievable in most asthmatics, not all asthmatics attain optimal asthma control. The difficulty is compounded further because patients, physicians and regulatory bodies have different perceptions of what is meant by asthma control. The challenge therefore remains as to how best to assess asthma control and define management strategies to ensure that this control is achieved and maintained. Despite the availability of several patient-based tools for assessing asthma control, these are mostly employed in a research setting or in selected specialist clinics. A symptom-based treatment approach also may have its limitations because patients can be poor judges of disease symptoms and severity and under-estimation may lead to inadequate treatment of airway inflammation and airway hyperresponsiveness (AHR) when treatment is administered as on-demand reliever therapy, since the effect of treatment on these underlying features occurs over a longer time course. The clinical benefits of sustained maintenance treatment for at least 3 months has been documented in recent studies of salmeterol/fluticasone propionate combination, which have demonstrated correlations between reduction in airway inflammation/AHR and reduction in exacerbation rates. In view of the putative limitations of a purely symptom-based asthma management plan, we suggest that treatment should be focussed on management of all aspects of the disease rather than management of symptoms alone, with a practical approach being treatment for a minimum of 3 months with an optimal dose to ensure maximal effects are seen on asthma control, airway inflammation, lung function, and remodelling.

What are the best estimates of pediatric asthma control?

PURPOSE OF REVIEW

To evaluate asthma outcome measures in the face of the variable nature of asthma. The outcome measures are divided into objective and subjective clinical measures, humanistic measures such as quality of life, and costs of asthma control.

RECENT FINDINGS

Objective measures of asthma include those traditionally used such as spirometry, peak expiratory flow rate, and airway hyperresponsiveness. Recently, more attention has been geared towards markers of inflammation including exhaled nitric oxide and sputum eosinophils. Subjective measures of asthma control include patient-derived parameters such as number of wheezing episodes, nocturnal symptoms, exercise-induced symptoms, short-acting beta-agonist use, steroid bursts, emergency-department visits, and hospitalizations. Asthma-related quality of life is related to asthma morbidity, and patients with better baseline quality of life have improved outcomes. Asthma-related costs include direct costs mostly comprised of hospitalizations and emergency-room visits, and indirect costs including school absenteeism.

SUMMARY

There is no ideal outcome measure for evaluating pediatric asthma control, but each of these outcome measures must be used together to evaluate a patient at each outpatient visit. Patient-centered measures of asthma control must also be further incorporated into office visits for improved asthma management.

Peak flow monitoring in clinical practice and clinical asthma trials

PURPOSE OF REVIEW

This review summarizes recent reports on peak expiratory flow (PEF) monitoring in clinical asthma trials and clinical practice.

RECENT FINDINGS

In clinical trials, summary measures such as average morning PEF provide only a fraction of the available information about asthma control and treatment response. New statistical models should improve the yield from PEF datasets. Improved criteria are needed for the diagnosis of exacerbations, and these may be developed from quality-control analysis of existing datasets. In clinical practice we must reduce the burden of monitoring and increase the ease of interpretation of PEF data. Electronic monitoring, with short message service or Internet communication, may assist with both. There is a need for standardized user-friendly PEF charts and simple statistically appropriate interpretative tools, which will facilitate the development of clinical algorithms and individualized written action plans. Normal values for diurnal variability should be updated to reflect twice daily monitoring.

SUMMARY

Current use of PEF data is limited by the burden of monitoring and the continuing use of interpretative tools that were originally developed for their practical feasibility rather than their clinical validity. Both of these problems may be improved by giving attention to methods for recording, displaying and analysing PEF data.