Offline exhaled nitric oxide in children: chemiluminescence vs. electrochemical devices / Óxido nítrico exhalado «fuera de línea¼ en niños: comparación entre equipos de quimioluminiscencia y electroquímicos

Abstract Background: Exhaled nitric oxide (eNO) is a noninvasive marker of airway inflammation that has been used in children, using the "offline" technique. To the extent of our knowledge, no article reported in literature compares the concordance and correlation between the two different technologies used to measure eNO at tidal volume offline. This study aimed to report the concordance and correlation of the eNO measured "offline" at tidal volume, using chemioluminiscence (cl) vs electrochemical devices (eq). Methods: A cross-sectional, observational, and prospective study was conducted in the National Institute of Respiratory Diseases (Instituto Nacional de Enfermedades Respiratorias), Mexico City. Healthy children and those with a lung disease between 1 and 11 years of age were included. The exhaled air sample at tidal volume was obtained by attaching a mask connected to a Mylar® bag. Results: We studied 36 children. The mean ± standard deviation (SD) age of the study population was 6 ± 2.6 years; 25% of the subjects included were healthy, and the rest had a lung disease. The concordance correlation coefficient between the two measuring devices was 0.98 (p < 0.001), with a mean difference of 1.46 ± 3.5 ppb and 95% limits of agreement from -5.3 ppb to 8.3 ppb. The linear regression model equation for the estimation of eNO was eNOcl = (eNOeq·1.0718) - 0.1343 (r2 = 0.97). Conclusions: The measurement of eNO at tidal volume by the offline method can be analyzed by electrochemical devices, and the results are interchangeable with those analyzed by chemiluminescence technology.

Resumen Introducción: El óxido nítrico exhalado (eNO) es un marcador no invasivo de inflamación de la vía aérea que se ha utilizado en niños mediante técnica «fuera de línea¼. Por lo que sabemos, en la literatura no existen reportes que comparen la concordancia y la correlación entre dos técnicas diferentes a volumen corriente. El objetivo de este trabajo es informar la concordancia y la correlación del eNO obtenido por la técnica fuera de línea a volumen corriente en los equipos de quimioluminiscencia (cl) y electroquímico (eq). Métodos: Se realizó un estudio transversal, observacional y prospectivo en el Instituto Nacional de Enfermedades Respiratorias, en Ciudad de México. Se incluyeron niños sanos y con enfermedad pulmonar de 1-11 años de edad. La muestra de aire exhalado se obtuvo a volumen corriente mediante una máscara con conexión a una bolsa de Mylar®. Resultados: Se estudiaron 36 niños. La edad promedio con su desviación estándar de la población de estudio fue de 6 ± 2.6 años. El 25% de los sujetos incluidos estaban sanos y el resto tenían alguna enfermedad pulmonar. El coeficiente de correlación de concordancia entre los dos equipos fue de 0.98 (p < 0.001), con una diferencia media de 1.46 ± 3.5 ppb y unos límites de concordancia del 95% de −5.3 a 8.3 ppb. La ecuación del modelo de regresión lineal del eNO fue eNOcl = (eNOeq·1,0718) − 0.1343 (r2 = 0.97). Conclusiones: La medición del eNO por el método fuera de línea a volumen corriente puede analizarse en dispositivos electroquímicos. Los resultados son intercambiables con los de quimioluminiscencia.

Cutoff value of lipid-laden alveolar macrophages for diagnosing aspiration in infants and children.

Chronic passage of gastric and/or alimentary material into the airways is a frequent and difficult-to-diagnose condition. Because alveolar macrophages phagocytose aspirated material, it has been suggested that their identification is a useful diagnostic method. To know the usefulness of the lipid-laden alveolar macrophages (LLAM) index as a diagnostic tool for aspiration, children from 1 month to 16 years of age were included in three groups: G-I, children with pulmonary pathology and suspicion of aspiration by clinic or image evaluation; G-II, with pulmonary pathology without suspicion of aspiration; and G-III, without respiratory symptoms nor suspicion of aspiration. Bronchoalveolar lavage was obtained through bronchoscopy in G-I and G-II, and through endotracheal tube in G-III, and the LLAM index (0-400) was determined. A total of 112 patients (41, 30, and 41 in G-I to III, respectively) were studied. LLAM index (mean +/- SEM) was highest in G-I (233.2 +/- 5.5), as compared with G-II (187.8 +/- 11.6, P < 0.05), and G-III (108.5 +/- 13.5, P < 0.001). However, notable overlap of LLAM values was observed between G-I and G-II, and between G-II and G-III. When patients from G-I and G-III were jointly analyzed, the area under the ROC curve for diagnosing aspiration was 0.92, with a best cutoff value of >165 (98.6% sensitivity, 78.0% specificity, 87.8% overall accuracy). LLAM index, with a cutoff value of >165 is a useful diagnostic test for aspiration when there is suspicion of this condition. However, due to its low specificity, it does not discriminate other causes of chronic lung disease.

Foreign body removal by flexible fiberoptic bronchoscopy in infants and children.

Rigid bronchoscopy is the preferred method for removal of foreign bodies lodged in the airways, but some studies found that flexible bronchoscopy can also achieve a high success rate. The aim of the present work was to report our experience in using flexible bronchoscopy for foreign body retrieval in infants and children. Reports of all bronchoscopies performed from 1994-2003 at a tertiary-level pediatric hospital in Mexico City were reviewed. Those with a final diagnosis of foreign body aspiration were analyzed. Of 2,376 bronchoscopies performed during the study period, 59 (2.5%) yielded a final diagnosis of foreign body aspiration: 28 lodged in the right bronchi, 15 in the left bronchi, and those remaining, in the larynx or trachea. Foreign bodies were organic in nature in 38 (64.4%), mainly peanuts, pumpkin seeds, and beans, while 21 (35.6%) were inorganic, mainly pen caps and pins. In 23 cases, flexible bronchoscopy was attempted as the initial therapeutic procedure. Among these latter patients, the procedure was successful in 21 (91.3%). Ages of these 21 patients ranged from 9 months to 16 years (median, 5 years). The only two patients in whom foreign bodies could not be removed through flexible bronchoscopy were males, 2 years of age, both with a peanut lodged in right main bronchus. In conclusion, flexible bronchoscopy must be taken into account as initial therapeutic method for foreign body removal in infants and children.