Larissa Andrade de Sá Feitosa

Diagnostic accuracy of exhaled nitric oxide in exercise-induced bronchospasm: Systematic review

INTRODUCTION The gold-standard method for the diagnosis of exercise-induced bronchospasm (EIB) is an exercise test combined with spirometry. However, this test is expensive, time consuming and requires specialized equipment and trained personnel. Exhaled nitric oxide (eNO) is a fast, easy, noninvasive method for the diagnosis of EIB. The aim of the present study was to assess the accuracy of the measurement of eNO for the diagnosis of EIB through a systematic review of the literature. METHODS A search was carried out in the PubMed, Lilacs, SciELO and SCOPUS databases by two independent researchers. RESULTS Fifty-six papers were found. Following the application of the eligibility criteria to the title, abstract and text, six papers remained for analysis. There was a significant heterogeneity in sex (X(2)=56.44, p=0.000) and clinical spectrum (X(2)=504.00, p=0.000) between studies. In children between 3.8 and 7.8 years old a cutoff point >28ppb EIB can be ruled in and in children between 5 and 16 years old at a cutoff point <20EIB can be ruled out. For adults a cutoff point <7EIB can be ruled out and it can be ruled in with a cutoff point >12. Four papers reported negative predictive values above 88%. CONCLUSION The measurement of eNO seems to be effective for ruling in and ruling out EIB in some specific groups. Therefore, the measurement of eNO levels could be an important tool to safely avoid the need for an exercise test when the result is negative, reducing the individual and economic impact of this disease.

Acute effects of incremental inspiratory loads on compartmental chest wall volume and predominant activity frequency of inspiratory muscle.

AIM This research aims to analyze the acute effect of incremental inspiratory loads on respiratory pattern and on the predominant activity frequency of inspiratory muscle, taking into account differences in gender responses. Optoelectronic Plethysmography was performed during loads in 39 healthy subjects (20 women), placing 89 markers on the thoracic-abdominal wall to obtain total and regional volumes. Surface electromyography (SEMG) was taken simultaneously on the Sternocleidomastoid and Diaphragm muscles, to calculate the predominant muscle activity frequency through wavelet analysis. Inspiratory loads were performed using Threshold(®)with 2 min of breathing at different levels, ranging from a load of 10 cmH(2)O plus 5 cmH(2)O to 40 cmH(2)O or fatigue. RESULTS Inspiratory Time increased during loads. Total and compartmental volumes increased with different regions, changing at different loads. These changes in volume occur earlier in women (20 cmH(2)O) than in men (30 cmH(2)O). The predominant activity frequency of Sternocleidmastoid muscle decreased at 30 cmH(2)O, while Diaphragm activity decreased at 40 cmH(2)O. CONCLUSION The acute effects of incremental inspiratory loads are increases of total and regional volumes and inspiratory time. As for muscle activity, the predominant activity frequency declined in Sternocleidomastoid and Diaphragm muscles, but at different loads. Such respiratory and SEMG patterns and gender differences should be considered when clinical interventions are performed.

Clinimetric properties of breath-stacking technique for assessment of inspiratory capacity.

BACKGROUND AND PURPOSE Breath stacking (BS) is used as an alternative method for lung expansion therapy and the assessment of inspiratory capacity in uncooperative patients. The aims of the present study were to identify the reproducibility of the BS technique in healthy volunteers and to compare BS with conventional spirometry with regard to inspiratory capacity. METHODS A cross-sectional study was carried out. Eighty-five healthy volunteers (21.78 ± 2.79 years; 41 men, 44 women) underwent spirometry and BS. Lung function, anthropometric and cardiopulmonary parameters were evaluated prior to the intervention. BS was performed with a unidirectional inspiratory valve by two different examiners. The order of each examiner was randomized. Spirometric tests were performed three times, and the BS manoeuvre was evaluated three times by each examiner. Respiratory rate, heart rate and peripheral arterial oxygen saturation were determined before, during and following the manoeuvre. RESULTS There were no statistically significant differences in the intra-examiner and inter-examiner analyses for the volume mobilized during BS, respiratory rate, duration of BS manoeuvre or perceived effort index (p > 0.05). The intra-class correlation coefficient was greater than 0.7 for all variables analysed. Maximal volumes achieved using the BS technique were significantly higher than those achieved with conventional spirometry (p < 0.0001). CONCLUSION Data from both the intra-examiner and inter-examiner analyses suggest that the BS technique is reproducible. This technique mobilizes greater lung volumes than conventional spirometry.

Accuracy of optoelectronic plethysmography in childhood exercise-induced asthma

ABSTRACT Objective: To assess the variations of end-expiratory volume of chest wall (EEVcw) measured by optoelectronic plethysmography (OEP) as a diagnostic tool in exercise-induced asthma (EIA) among asthmatic preschool children. Methods: Forty children diagnosed with asthma were included in the study. Spirometry was used as a gold standard test for comparison with OEP. A 10% decline in forced expiratory volume in 1 second was considered positive for EIA. OEP was performed with 8 cameras at a frequency of 60 Hz and 89 markers were placed on the thoraco-abdominal surface of participants. Following bronchoprovocation testing on a treadmill, series of OEP and spirometry were conducted between 5 and 30 minutes after exercise. To obtain the ideal cut-off point, a receiver operating characteristic (ROC) curve was constructed for the largest EEVcw. The highest Youden index was used as criteria to obtain the cut-off point with the best sensitivity and specificity. Results: Of the 40 children studied, 16 had EIA. According to the ROC curve, the cut-off point of 0.185% for EEWcw provided mean sensitivity (95% confidence interval) of 93.75% (0.69–0.99), for a specificity of 83.33% (0.63–0.95), when using the largest increase in the period of 5–30 minutes post-exercise. The low area of the ROC was 0.93 (0.85–1.00) for p < 0.001. Conclusion: OEP can be accurately used to replace spirometry in asthmatic children unable to adequately execute the required manoeuvres.

Influência dos corticosteroides inalatórios nas pressões respiratórias máximas de crianças escolares asmáticas

INTRODUCTION: The inhaled corticosteroid (IC) is the mean therapy used for the preventive and maintenance treatment of asthma. Overdose or prolonged use of IC can cause some collateral effects as remission in bone growth, adrenal suppression and myopathy. OBJECTIVES: To evaluate the influence of inhaled corticosteroids in the inspiratory and expiratory strength in asthmatic school children. MATERIALS AND METHODS: A cross-sectional, observational study, that included 60 children between 6 to 12 years divided into three groups: control (CG), asthma (AG) and children whose used IC for at least three months (AG+IC). The maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured in 3 different days with 12 days between them. RESULTS: The mean ± SD of MIP in the third day was - (65.4 ± 21.9), - (74.9 ± 19.5) and - (80.7 ± 21.5) cmH2O to the AG, AG+IC and CG, respectively. The MIP in the AG was lesser than in the CG (p < 0.05). The mean ± SD of MEP in the third day was 52.7 ± 14.8; 61.7 ± 17.4; and 75.6 ± 18.4 cmH2O to the AG, AG+IC and CG, respectively. The MEP was superior in the CG than in the AG (p < 0.05). The MEP was superior in the CG than the AG+CI (p < 0.05). CONCLUSIONS:The results suggest that IC promotes a major control of pulmonary hiperinflation with the increase of MIP in asthmatic children, but decrease the MEP probably by the effect in the type II muscles fibers.