Prediction equations for spirometry in four- to six-year-old children / Equações de predição da espirometria em crianças de quatro a seis anos

Abstract Objective To generate prediction equations for spirometry in 4- to 6-year-old children. Methods Forced vital capacity, forced expiratory volume in 0.5 s, forced expiratory volume in one second, peak expiratory flow, and forced expiratory flow at 25–75% of the forced vital capacity were assessed in 195 healthy children residing in the town of Sete Lagoas, state of Minas Gerais, Southeastern Brazil. The least mean squares method was used to derive the prediction equations. The level of significance was established as p < 0.05. Results Overall, 85% of the children succeeded in performing the spirometric maneuvers. In the prediction equation, height was the single predictor of the spirometric variables as follows: forced vital capacity = exponential [(−2.255) + (0.022 × height)], forced expiratory volume in 0.5 s = exponential [(−2.288) + (0.019 × height)], forced expiratory volume in one second = exponential [(−2.767) + (0.026 × height)], peak expiratory flow = exponential [(−2.908) + (0.019 × height)], and forced expiratory flow at 25–75% of the forced vital capacity = exponential [(−1.404) + (0.016 × height)]. Neither age nor weight influenced the regression equations. No significant differences in the predicted values for boys and girls were observed. Conclusion The predicted values obtained in the present study are comparable to those reported for preschoolers from both Brazil and other countries.

Resumo Objetivo Gerar equações de predição da espirometria em crianças de quatro a seis anos. Métodos Capacidade vital forçada, volume expiratório forçado em 0,5 segundo, volume expiratório forçado em um segundo, pico de fluxo expiratório e fluxo expiratório forçado com 25-75% da capacidade vital forçada foram avaliados em 195 crianças saudáveis que residem em Sete Lagoas, Estado de Minas Gerais, Sudeste do Brasil. O método dos mínimos quadrados foi usado para derivar as equações de predição. O nível de significância foi estabelecido como p < 0,05. Resultados No geral, 85% das crianças foram bem-sucedidas ao fazer as manobras espirométricas. Na equação de predição, a estatura foi a única variável preditora das variáveis espirométricas, da seguinte forma: capacidade vital forçada = exponencial [(-2,255) + (0,022 x estatura)], volume expiratório forçado em 0,5 segundo = exponencial [(-2,288) + (0,019 x estatura)], volume expiratório forçado em um segundo = exponencial [(-2,767) + (0,026 x estatura)], pico do fluxo expiratório = exponencial [(-2,908) + (0,019 x estatura)] e fluxo expiratório forçado com 25-75% da capacidade vital forçada = exponencial [(-1,404) + (0,016 x estatura)]. Nem a idade nem o peso influenciaram as equações de regressão. Não foi observada diferença significativa nos valores previstos em meninos e meninas. Conclusão Os valores previstos obtidos neste estudo são comparáveis àqueles relatados em crianças em idade pré-escolar tanto do Brasil quanto de outros países.

Prediction equations for spirometry in four- to six-year-old children.

OBJECTIVE: To generate prediction equations for spirometry in 4- to 6-year-old children. METHODS: Forced vital capacity, forced expiratory volume in 0.5s, forced expiratory volume in one second, peak expiratory flow, and forced expiratory flow at 25-75% of the forced vital capacity were assessed in 195 healthy children residing in the town of Sete Lagoas, state of Minas Gerais, Southeastern Brazil. The least mean squares method was used to derive the prediction equations. The level of significance was established as p<0.05. RESULTS: Overall, 85% of the children succeeded in performing the spirometric maneuvers. In the prediction equation, height was the single predictor of the spirometric variables as follows: forced vital capacity=exponential [(-2.255)+(0.022×height)], forced expiratory volume in 0.5s=exponential [(-2.288)+(0.019×height)], forced expiratory volume in one second=exponential [(-2.767)+(0.026×height)], peak expiratory flow=exponential [(-2.908)+(0.019×height)], and forced expiratory flow at 25-75% of the forced vital capacity=exponential [(-1.404)+(0.016×height)]. Neither age nor weight influenced the regression equations. No significant differences in the predicted values for boys and girls were observed. CONCLUSION: The predicted values obtained in the present study are comparable to those reported for preschoolers from both Brazil and other countries.

Effect of slow expiration with glottis opened in lateral posture (ELTGOL) on mucus clearance in stable patients with chronic bronchitis.

BACKGROUND: Slow expiration with glottis opened in lateral posture (ELTGOL, l'expiration lente totale glotte ouverte en infralatéral) has been used in clinical practice to improve mucus clearance from peripheral airways. The purpose of this crossover study was to evaluate the effect of ELTGOL on mucus clearance of right and left lungs, especially of peripheral lung areas, in stable patients with chronic bronchitis. METHODS: Twelve 45-75-year-old patients with chronic bronchitis were studied (10 of whom had mild to moderate COPD according to the Global Initiative for Chronic Obstructive Lung Disease guidelines). Control and ELTGOL interventions were performed on a randomized allocation of subjects. Mucus clearance was measured through 6 posterior scintigraphy images taken with the patient in the right lateral decubitus position 20 (T1), 40 (T2), 60 (T3), 80 (T4), and 120 (T5) min after baseline image (T0). In the control intervention only ventilatory scintigraphy measurements were performed. During ELTGOL the technique was performed after the baseline image (T0). RESULTS: Significant increases in mucus clearance from the peripheral area were found only in the right lung, and were observed at all times during ELTGOL (P < .05) except T1. Significant increases in mucus clearance were observed at all times studied in the total area of the right lung and in the left lung at T1 and T2. For the intermediate area and central areas, results were similar in both lungs. CONCLUSIONS: ELTGOL was efficient in increasing peripheral airway clearance in dependent lung of patients with chronic bronchitis, most of them with mild to moderate COPD.

Interação paciente ventilador nas diferentes fases do ciclo ventilatório em ventilação por pressão de suporte / Patient-ventilator interaction on different phases of mechanical breath in pressure support ventilation

Introdução: O principal objetivo da ventilação mecânica é a diminuição do trabalho respiratório. Para que isto ocorra, o ciclo mecânico deveria coincidir com o tempo inspiratório neural do paciente. A assincronia paciente ventilador ocorre por fatores relacionados ao paciente e aos parâmetros ventilatórios e podem prolongar o tempo de suporte mecânico e permanência em unidades de terapia intensiva. Objetivos: Revisar a assincronia nas diferentes fases do ciclo respiratório, sua avaliação através dos gráficos e as intervenções capazes de melhorar a interação paciente ventilador em ventilação por pressão de suporte. Resultados/ Discussão: Através de busca em base de dados científicos, foram incluídos 26 artigos que abordavam o tema proposto. Os diferentes tipos de assincronia podem ser observados através de esforços ineficientes, atrasos no disparo, disparos automáticos, disparos duplos, presença de PEEP intrínseca, términos prematuro ou prolongado da inspiração e curvas diferentes do padrão usual. Conclusão: A correta identificação e ajustes conforme a demanda do paciente são pontos importantes na interação paciente ventilador e podem contribuir para a melhora do prognóstico destes pacientes.(AU)

Introduction: The main reason of mechanical ventilation is the decrease the work of breathing. To achieve it, the mechanical breath should coincide with the neural inspiratory time. Patient-ventilator asynchrony may be secondary for the facts related to the patient´s condition or ventilatory settings and may prolong support and UTI stay. Objectives: Review asynchrony in different phases of mechanical breath, the evaluation through ventilator waveforms and the proper settings to improve patient-ventilator interaction in pressure support ventilation. Results/ Discussion: Through research on scientific basis, 26 studies that match the theme were included. Asynchrony may be seen as inefficient efforts, trigger delay, auto-triggering, double triggering, presence of auto-PEEP, premature termination, delayed termination or unusual waveforms. Conclusion: Proper identification and adjustments that coincides with patient´s demand are critical points in patient ventilator interaction and may contribute to improve their prognosis.(AU)

Reliability and accuracy of cirtometry in healthy adults.

OBJECTIVE: To determine the intrarater and interrater reliability of cirtometry (measurements of the circumference of the chest and abdomen taken during respiratory movements) as well as its correlation with pulmonary volumes measured by respiratory inductive plethysmography. METHODS: A total of 40 healthy individuals were evaluated. The mean age was 28 years. The measurements were taken in the supine position at three different time points: at rest, at maximal inspiration, and at maximal expiration. Two trained investigators, each of whom was blinded as to the results obtained by the other, performed the measurements. The Friedman test was used to determine intrarater reliability, and the Wilcoxon test, together with the intraclass correlation coefficient, were used to determine interrater reliability. The correlation between the cirtometry measurements and the plethysmography results was obtained using Spearman's correlation coefficient. The level of significance was set at 0.05 for all tests. RESULTS: Intrarater reliability was satisfactory. Regarding interrater reliability, statistically significant differences (2.8 cm at the most) were found in all sets of measurements. However, through the analysis of the intraclass correlation coefficient, the investigators were found to be responsible only for a small portion of the variability (1.2-5.08%) found among the measurements. When the cirtometry measurements were compared to the volumes measured by respiratory inductive plethysmography, low correlations (range, r = 0.170-0.343) were found. CONCLUSIONS: The findings of this study suggest that, although cirtometry is a reliable measurement, it does not accurately measure pulmonary volumes.

Precisão e acurácia da cirtometria em adultos saudáveis / Reliability and accuracy of cirtometry in healthy adults

OBJETIVO: Avaliar a confiabilidade intra-examinador e inter-examinadores da cirtometria (conjunto de medidas das circunferências de tórax e abdômen durante os movimentos respiratórios) e sua correlação com volumes pulmonares medidos por meio da pletismografia respiratória por indutância. MÉTODOS: Quarenta indivíduos saudáveis, com média de idade de 28 anos, foram avaliados. As medidas foram realizadas em decúbito dorsal em três momentos: em repouso, em inspiração máxima e em expiração máxima. Dois examinadores treinados, os quais foram cegados, realizaram as medidas. Utilizou-se o teste de Friedman para avaliar a confiabilidade intra-examinador e foram utilizados o teste de Wilcoxon e o coeficiente de correlação intraclasse para avaliar a confiabilidade inter-examinadores. A correlação entre os resultados da cirtometria e da pletismografia foi obtida por meio do coeficiente de correlação de Spearman. Para todos os testes, considerou-se um nível de significância estatística de 0,05. RESULTADOS: Os resultados mostraram confiabilidade intra-examinador adequada. Em relação à confiabilidade inter-examinadores, foram observadas diferenças estatisticamente significativas (de no máximo 2,8 cm) em todas os conjuntos de medidas.No entanto, por meio da análise do coeficiente de correlação intraclasse, observou-se que os examinadores foram responsáveis apenas por pequena parte da variabilidade (1,2-5,08 por cento) observada entre as medidas. Quando as medidas da cirtometria foram comparadas aos volumes pulmonares medidos por meio da pletismografia respiratória por indutância, encontraram-se correlações de baixa magnitude (variação de r = 0,170-0,343). CONCLUSÕES: Os resultados deste estudo sugerem que a cirtometria constitui uma medida precisa, mas não acurada, para aferir volumes pulmonares.

ABSTRACT OBJECTIVE: To determine the intrarater and interrater reliability of cirtometry (measurements of the circumference of the chest and abdomen taken during respiratory movements) as well as its correlation with pulmonary volumes measured by respiratory inductive plethysmography. METHODS: A total of 40 healthy individuals were evaluated. The mean age was 28 years. The measurements were taken in the supine position at three different time points: at rest, at maximal inspiration, and at maximal expiration. Two trained investigators, each of whom was blinded as to the results obtained by the other, performed the measurements. The Friedman test was used to determine intrarater reliability, and the Wilcoxon test, together with the intraclass correlation coefficient, were used to determine interrater reliability. The correlation between the cirtometry measurements and the plethysmography results was obtained using Spearman's correlation coefficient. The level of significance was set at 0.05 for all tests. RESULTS: Intrarater reliability was satisfactory. Regarding interrater reliability, statistically significant differences (2.8 cm at the most) were found in all sets of measurements. However, through the analysis of the intraclass correlation coefficient, the investigators were found to be responsible only for a small portion of the variability (1.2-5.08 percent) found among the measurements. When the cirtometry measurements were compared to the volumes measured by respiratory inductive plethysmography, low correlations (range, r = 0.170-0.343) were found. CONCLUSIONS: The findings of this study suggest that, although cirtometry is a reliable measurement, it does not accurately measure pulmonary volumes.