Simpatectomía dorsal bilateral en el tratamiento de la hiperhidrosis esencial: efectos a los 3 años sobre la función pulmonar / Bilateral dorsal sympathectomy for the treatment of primary hyperhidrosis: effects on lung function at 3 years

Introducción La hiperhidrosis esencial se caracteriza por un exceso de sudoración en la palma de las manos, la planta de los pies y las axilas, debida a una hiperestimulación del sistema nervioso simpático que pasa a través del segundo y tercer ganglios torácicos simpáticos. El tratamiento de elección es la simpatectomía dorsal bilateral (SDB) por videotoracoscopia. El objetivo de nuestro estudio ha sido evaluar si las modificaciones en la función respiratoria halladas previamente en un grupo de pacientes intervenidos por SDB se mantenían a los 3 años de la cirugía. Pacientes y métodos Del grupo de 20 pacientes estudiados previamente, pudimos reunir a 18 (3 varones y 15 mujeres) con una edad media de 35 años. Se les realizaron una espirometría y una prueba de provocación bronquial con metacolina, y se determinó la concentración de óxido nítrico en aire espirado. Los resultados se compararon con los de las pruebas efectuadas antes de la cirugía. Resultados A los 3 años se detectó un incremento estadísticamente significativo del porcentaje de la capacidad vital forzada basal, que pasó de un valor medio (±desviación estándar) del 96±10% al 101±11% (p=0,008). Respecto a las cifras iniciales del flujo máximo mesoespiratorio, se halló un descenso estadísticamente significativo a los 3 años de la cirugía: de un valor basal de 3,8±0,9l/s se pasó a 3,5±0,9l/s (p=0,01). La prueba de provocación bronquial con metacolina y la concentración de óxido nítrico en aire espirado no experimentaron cambios a los 3 años. Conclusiones Las modificaciones en la función pulmonar indican una mínima afectación de la pequeña vía aérea, que persiste a los 3 años de la SDB, como consecuencia de la denervación simpática producida por la cirugía, pero sin ninguna significación clínica(AU)

Introduction Primary hyperhidrosis is characterized by excessive sweating of the palms, soles, and axillae due to overactivity of the sympathetic nervous system at the level of the second and third sympathetic thoracic ganglia. The treatment of choice is bilateral dorsal sympathectomy performed using video-assisted thoracic surgery (VATS). The objective of our study was to determine whether lung function changes observed in a group of patients prior to bilateral dorsal sympathectomy performed using VATS were still evident 3 years after surgery. Patients and methods Of the 20 patients studied at baseline, we were able to obtain data for 18 (3 men and 15 women; mean age, 35 y). They underwent spirometry and a bronchial challenge test with methacholine, and the fraction of exhaled nitric oxide (FENO) was measured. The results were compared with those of the tests performed before surgery. Results At 3 years from baseline, we detected a statistically significant increase in forced vital capacity from a mean (SD) of 96% (10%) to 101% (11%) (P=.008), and a statistically significant decrease in midexpiratory flow rate from 3.8 (0.9)L/s to 3.5 (0.9)L/s (P=.01). The results of the bronchial challenge test with methacholine and the FENO remained unchanged. Conclusions The lung function changes detected point toward minimal, clinically insignificant small airway alterations due to sympathetic denervation following bilateral dorsal sympathectomy performed 3 years earlier(AU)

[Bilateral dorsal sympathectomy for the treatment of primary hyperhidrosis: effects on lung function at 3 years]. / Simpatectomía dorsal bilateral en el tratamiento de la hiperhidrosis esencial: efectos a los 3 años sobre la función pulmonar.

INTRODUCTION: Primary hyperhidrosis is characterized by excessive sweating of the palms, soles, and axillae due to overactivity of the sympathetic nervous system at the level of the second and third sympathetic thoracic ganglia. The treatment of choice is bilateral dorsal sympathectomy performed using video-assisted thoracic surgery (VATS). The objective of our study was to determine whether lung function changes observed in a group of patients prior to bilateral dorsal sympathectomy performed using VATS were still evident 3 years after surgery. PATIENTS AND METHODS: Of the 20 patients studied at baseline, we were able to obtain data for 18 (3 men and 15 women; mean age, 35 y). They underwent spirometry and a bronchial challenge test with methacholine, and the fraction of exhaled nitric oxide (FE(NO)) was measured. The results were compared with those of the tests performed before surgery. RESULTS: At 3 years from baseline, we detected a statistically significant increase in forced vital capacity from a mean (SD) of 96% (10%) to 101% (11%) (P=.008), and a statistically significant decrease in midexpiratory flow rate from 3.8 (0.9)L/s to 3.5 (0.9)L/s (P=.01). The results of the bronchial challenge test with methacholine and the FE(NO) remained unchanged. CONCLUSIONS: The lung function changes detected point toward minimal, clinically insignificant small airway alterations due to sympathetic denervation following bilateral dorsal sympathectomy performed 3 years earlier.

Medición del patrón ventilatorio mediante tomografía por impedancia eléctrica en pacientes con EPOC / Measuring Breathing Pattern in Patients With Chronic Obstructive Pulmonary Disease by Electrical Impedance Tomography

Introducción. La medición del patrón ventilatorio (PV) en pacientes con enfermedad pulmonar obstructiva crónica (EPOC) mediante tomografía por impedancia eléctrica (TIE) requiere disponer de un modelo matemático de calibración que tenga en cuenta no sólo las características antropométricas (ya evaluadas en la persona sana), sino probablemente también las alteraciones funcionales propias de la enfermedad. El objetivo del presente estudio ha sido relacionar, en un grupo de pacientes (varones) con EPOC, las variables de la función pulmonar espirometría, volúmenes estáticos, transferencia de monóxido de carbono (CO) con las determinaciones de TIE y obtener una ecuación de calibración que permita convertir la señal eléctrica de la TIE en una señal de volumen.Material y métodosSe estudió a 28 pacientes volumen espiratorio forzado en el primer segundo (FEV1)/capacidad vital forzada (FVC)<70% con un equipo TIE-4 previamente validado y se compararon los resultados con los de un neumotacómetro estándar. Previamente se determinaron los siguientes parámetros: FVC, FEV1, FEV1/FVC, volumen residual, capacidad pulmonar total, capacidad de difusión de CO y coeficiente de transferencia de CO (KCO), además de las variables antropométricas habituales.ResultadosLos valores medios (±desviación estándar) de las diferentes pruebas funcionales fueron: FVC del 72±16%; FEV1 del 43±14%; FEV1/FVC del 42±9%; volumen residual del 161±44%, capacidad pulmonar total del 112±17%; capacidad de difusión de CO del 58±17%, y KCO del 76±25%. Los valores medios de volumen circulante de las determinaciones obtenidas con el neumotacómetro y la TIE fueron de 0,697±0,181 y 0,515±0,223l, respectivamente (p<0,001). Se encontraron relaciones significativas entre las medidas de la TIE y la transferencia de CO. El modelo matemático para ajustar las diferencias entre ambas determinaciones (R2=0,568; p<0,001) fue: factor de compensación=1,81 0,82×talla (m) 0,004×KCO (%). Conclusiones. La medición del PV mediante un equipo de TIE en pacientes con EPOC requiere una calibración previa que tenga en cuenta no sólo las características físicas de cada individuo, sino además la situación funcional del área de intercambio gaseoso (AU)

Background and ObjectiveThe measurement of breathing pattern in patients with chronic obstructive pulmonary disease (COPD) by electrical impedance tomography (EIT) requires the use of a mathematical calibration model incorporating not only anthropometric characteristics (previously evaluated in healthy individuals) but probably functional alterations associated with COPD as well. The aim of this study was to analyze the association between EIT measurements and spirometry parameters, static lung volumes, and carbon monoxide diffusing capacity (DLCO) in a group of male patients to develop a calibration equation for converting EIT signals into volume signals.Materials and MethodsWe measured forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC, residual volume, total lung capacity, DLCO, carbon monoxide transfer coefficient (KCO) and standard anthropometric parameters in 28 patients with a FEV1/FVC ratio of <70%. We then compared tidal volume measurements from a previously validated EIT unit and a standard pneumotachometer.ResultsThe mean (SD) lung function results were FVC, 72 (16%); FEV1, 43% (14%); FEV1/FVC, 42% (9%); residual volume, 161% (44%); total lung capacity, 112% (17%); DLCO, 58% (17%); and KCO, 75% (25%). Mean (SD) tidal volumes measured by the pneumotachometer and the EIT unit were 0.697 (0.181)L and 0.515 (0.223)L, respectively (P<.001). Significant associations were found between EIT measurements and CO transfer parameters. The mathematical model developed to adjust for the differences between the 2 measurements (R2=0.568; P<.001) was compensation factor=1.81o 0.82o× height (m)o 0.004×KCO (%).ConclusionsThe measurement of breathing pattern by EIT in patients with COPD requires the use of a previously calculated calibration equation that incorporates not only individual anthropometric characteristics but gas exchange parameters as well(AU)

[Measuring breathing pattern in patients with chronic obstructive pulmonary disease by electrical impedance tomography]. / Medición del patrón ventilatorio mediante tomografía por impedancia eléctrica en pacientes con EPOC.

BACKGROUND AND OBJECTIVE: The measurement of breathing pattern in patients with chronic obstructive pulmonary disease (COPD) by electrical impedance tomography (EIT) requires the use of a mathematical calibration model incorporating not only anthropometric characteristics (previously evaluated in healthy individuals) but probably functional alterations associated with COPD as well. The aim of this study was to analyze the association between EIT measurements and spirometry parameters, static lung volumes, and carbon monoxide diffusing capacity (DLCO) in a group of male patients to develop a calibration equation for converting EIT signals into volume signals. MATERIALS AND METHODS: We measured forced vital capacity (FVC), forced expiratory volume in 1 second (FEV(1)), FEV(1)/FVC, residual volume, total lung capacity, DLCO, carbon monoxide transfer coefficient (KCO) and standard anthropometric parameters in 28 patients with a FEV(1)/FVC ratio of <70%. We then compared tidal volume measurements from a previously validated EIT unit and a standard pneumotachometer. RESULTS: The mean (SD) lung function results were FVC, 72 (16%); FEV(1), 43% (14%); FEV(1)/FVC, 42% (9%); residual volume, 161% (44%); total lung capacity, 112% (17%); DLCO, 58% (17%); and KCO, 75% (25%). Mean (SD) tidal volumes measured by the pneumotachometer and the EIT unit were 0.697 (0.181)L and 0.515 (0.223)L, respectively (P<.001). Significant associations were found between EIT measurements and CO transfer parameters. The mathematical model developed to adjust for the differences between the 2 measurements (R(2)=0.568; P<.001) was compensation factor=1.81# - 0.82# height (m)# -0.004 x KCO (%). CONCLUSIONS: The measurement of breathing pattern by EIT in patients with COPD requires the use of a previously calculated calibration equation that incorporates not only individual anthropometric characteristics but gas exchange parameters as well.

[Determining the alveolar component of nitric oxide in exhaled air: procedures and reference values for healthy persons]. / Determinación de la concentración de óxido nítrico alveolar en aire espirado: procedimiento y valores de referencia en personas sanas.

Nitric oxide (NO) production has been described using a 2-compartment model for the synthesis and movement of NO in both the alveoli and the airways. The alveolar concentration of NO (Ca(NO)), an indirect marker of the inflammatory state of the distal portions of the lung, can be deduced through exhalation at multiple flow rates. Our objective was to determine reference values for Ca(NO). The fraction of exhaled NO (Fe(NO)) was measured in 33 healthy individuals at a rate of 50mL/s; the subjects then exhaled at 10, 30, 100, and 200mL/s to calculate Ca(NO). A chemiluminescence analyzer (NIOX Aerocrine) was used to perform the measurements. The mean (SD) Fe(NO) was 15 (6)ppb. The mean Ca(NO) was 3.04 (1.30)ppb. These values of Ca(NO) measured in healthy individuals will allow us to analyze alveolar inflammatory behavior in respiratory and systemic processes.

Determinación de la concentración de óxido nítrico alveolar en aire espirado: procedimiento y valores de referencia en personas sanas / Determining the Alveolar Component of Nitric Oxide in Exhaled Air: Procedures and Reference Values for Healthy Persons

La producción de óxido nítrico (NO) se describe mediante un modelo bicompartimental que relaciona la producción y la movilidad de NO desde los alvéolos hacia las vías aéreas. La espiración a múltiples flujos permite deducir la concentración alveolar de NO (CaNO), marcador indirecto del estado inflamatorio de las zonas distales del pulmón. El objetivo fue determinar los valores de referencia de CaNO. En 33 individuos sanos se determinaron la concentración espirada de NO (FeNO) a 50ml/s y la CaNO a 10, 30, 100 y 200ml/s mediante un sensor de quimioluminiscencia (NIOX Aerocrine). El valor medio (± desviación estándar) de FeNO fue de 15±6ppb y de CaNO fue de 3,04±1,30ppb. Los valores de CaNO obtenidos en individuos sanos permitirán analizar el comportamiento inflamatorio alveolar en procesos respiratorios y sistémicos(AU)

Nitric oxide (NO) production has been described using a 2-compartment model for the synthesis and movement of NO in both the alveoli and the airways. The alveolar concentration of NO (CaNO), an indirect marker of the inflammatory state of the distal portions of the lung, can be deduced through exhalation at multiple flow rates. Our objective was to determine reference values for CaNO. The fraction of exhaled NO (FeNO) was measured in 33 healthy individuals at a rate of 50mL/s; the subjects then exhaled at 10, 30, 100, and 200mL/s to calculate CaNO. A chemiluminescence analyzer (NIOX Aerocrine) was used to perform the measurements. The mean (SD) FeNO was 15 (6)ppb. The mean CaNO was 3.04 (1.30)ppb. These values of CaNO measured in healthy individuals will allow us to analyze alveolar inflammatory behavior in respiratory and systemic processes(AU)

Duration of pulmonary rehabilitation to achieve a plateau in quality of life and walk test in COPD.

OBJECTIVE: To address the minimum duration of pulmonary rehabilitation necessary for patients with chronic obstructive pulmonary disease (COPD) to achieve a plateau in Health-Related Quality of Life (HRQL) and exercise tolerance. METHODS: COPD patients with a dyspnea rating of at least 2 on the Medical Research Council scale participated in an outpatient rehabilitation program of 3 weekly sessions for 12 weeks. Measurements included HRQL and exercise tolerance 2 weeks before the program started and every 2 weeks thereafter. Patients were considered to have reached a plateau if they showed no improvement beyond 20% of the minimal important difference between 2 consecutive evaluations on HRQL score or walk tests. RESULTS: Twenty-eight patients participated. The number of patients achieving stability after 8 weeks, showing continued improvement after 8 weeks, and demonstrating an erratic pattern of change was as follows: for physical function 16 (56%), 10 (37%) and 2 (7%) patients; for emotional function 22 (79%), 5 (18%) and 1 (4%); and for 6-min walk test 21 (75%), 5 (18%) and 2 (7%). More severe patients demonstrated a greater likelihood (76%) of achieving stability in physical function at 12 weeks than did less severe patients (27%; p on difference=0.003). The likelihood of stability at 12 weeks in emotional function and the 6-min walk test did not differ by severity. CONCLUSIONS: A program of 3 weekly 3-h sessions of outpatient pulmonary rehabilitation program should last at least 8 weeks in order to achieve optimal HRQL and exercise tolerance for most patients.

Metodología estadística en los estudios de comparación de métodos de medida. Respuesta de los autores / No disponible

No disponible

[Assessment of differential lung function by electrical impedance tomography]. / Evaluación de la función pulmonar unilateral mediante tomografía por impedancia eléctrica.

OBJECTIVE: To compare unilateral lung function estimated by 2 methods: electrical impedance tomography (EIT) and ventilation-perfusion lung scintigraphy. PATIENTS AND METHODS: This prospective clinical study was carried out in the pulmonary function laboratory of a general hospital. Twenty patients diagnosed with lung cancer (17 men and 3 women, ranging in age from 25 to 77 years) who were candidates for lung resection underwent ventilation-perfusion lung scanning breathing a radioactive gas. Differential lung function was estimated based on images taken at 2 intercostal spaces in which ventilation and perfusion were represented by changes in bioelectrical impedance. Each lung's contribution to overall respiratory function was also calculated based on scintigraphy. RESULTS: The right lung contributed a mean (SD) of 54% (9%) of ventilation (range, 32%-71%) according to EIT. Scintigraphy similarly estimated the right lung's contribution to be 52% (10%) of total ventilation (range, 31%-80%) and 50% (9%) of perfusion (range, 37%-71%). The difference between the 2 estimates was not significant (t test), and the correlation coefficients between them were r=0.90 for ventilation and r=0.72 for perfusion (P< .05 in both cases). The analysis of agreement showed that the mean difference between the methods was 1.9% (95% confidence interval [CI], 10.5% to -6.8%) for ventilation and 3.4% (95% CI, 17.1% to -10.3%) for perfusion. CONCLUSIONS: EIT is able to estimate differential lung function as accurately as ventilation-perfusion scintigraphy.

Evaluación de la función pulmonar unilateral mediante tomografía por impedancia eléctrica / Assessment of differential lung function by electrical impedance tomography

OBJETIVO: Comparar la función pulmonar unilateral (FPU) estimada mediante tomografía por impedancia eléctrica (TIE) con la misma determinación obtenida a partir de la gammagrafía de ventilación y perfusión pulmonar PACIENTES Y MÉTODOS: Se trata de un estudio clínico prospectivo, realizado en un laboratorio de función pulmonar de un hospital general. Se incluyó a 20 pacientes diagnosticados de cáncer de pulmón (17 varones y 3 mujeres, con edades comprendidas entre los 25 y los 77 años), candidatos a cirugía resectiva pulmonar, a quienes se realizó un estudio de ventilación/perfusión pulmonar con radioisótopos. La FPU se calculó a partir de imágenes en 2 espacios intercostales en las que se representaban la ventilación y la perfusión relacionadas con los cambios en la bioimpedancia eléctrica. Se determinó asimismo la participación de cada pulmón en la función global a partir de estudios isotópicos. RESULTADOS: El valor promedio ± desviación estándar de ventilación en el pulmón derecho obtenido mediante TIE fue del 54 ± 9% (rango: 32-71%). El mismo valor mediante radioisótopos fue del 52 ± 10% (rango: 31-80%) para la ventilación y del 50 ± 9% (rango: 37-71%) para la perfusión (prueba de la t de Student, p no significativa). El coeficiente de correlación entre ambas determinaciones fue de r = 0,90 (p < 0,05) para la ventilación y de r = 0,72 (p < 0,05) para la perfusión. El análisis de concordancia mostró una media de las diferencias del 1,9% (intervalo de confianza del 95%, del 10,5 al -6,8%) para la ventilación y del 3,4% (intervalo de confianza del 95%, entre el 17,1 y el -10,3%) para la perfusión. CONCLUSIONES: La TIE es capaz de cuantificar la FPU con una precisión similar a la gammagrafía de ventilación o perfusión con radioisótopos

OBJECTIVE: To compare unilateral lung function estimated by 2 methods: electrical impedance tomography (EIT) and ventilation-perfusion lung scintigraphy. PATIENTS AND METHODS: This prospective clinical study was carried out in the pulmonary function laboratory of a general hospital. Twenty patients diagnosed with lung cancer (17 men and 3 women, ranging in age from 25 to 77 years) who were candidates for lung resection underwent ventilation-perfusion lung scanning breathing a radioactive gas. Differential lung function was estimated based on images taken at 2 intercostal spaces in which ventilation and perfusion were represented by changes in bioelectrical impedance. Each lung's contribution to overall respiratory function was also calculated based on scintigraphy. RESULTS: The right lung contributed a mean (SD) of 54% (9%) of ventilation (range, 32%-71%) according to EIT. Scintigraphy similarly estimated the right lung's contribution to be 52% (10%) of total ventilation (range, 31%-80%) and 50% (9%) of perfusion (range, 37%-71%). The difference between the 2 estimates was not significant (t test), and the correlation coefficients between them were r=0.90 for ventilation and r=0.72 for perfusion (P<.05 in both cases). The analysis of agreement showed that the mean difference between the methods was 1.9% (95% confidence interval [CI], 10.5% to -6.8%) for ventilation and 3.4% (95% CI, 17.1% to -10.3%) for perfusion. CONCLUSIONS: EIT is able to estimate differential lung function as accurately as ventilation-perfusion scintigraphy

Diagnostic utility of inflammatory biomarkers in asthma: exhaled nitric oxide and induced sputum eosinophil count.

BACKGROUND: Even though an inflammatory process is known to be the underlying cause of asthma, diagnosis is based on clinical history, reversible airway obstruction and bronchial hyperresponsiveness according to international guidelines. The fraction of exhaled nitric oxide (FE(NO)) and induced sputum eosinophil count (Eos%) have been used as non-invasive inflammatory biomarkers. OBJECTIVES: The aim of this study was to compare the sensitivity and specificity of FE(NO), Eos% and spirometry and to assess whether their combined use in clinical practice would improve diagnostic yield. METHODS: In 50 patients with asthma symptoms we performed spirometry, a methacholine challenge test, FE(NO) measurement and assessment of Eos% in induced sputum. The standard diagnosis of asthma followed the guidelines of the Global Initiative for Asthma. RESULTS: Twenty-two of the 50 patients were diagnosed with asthma. The sensitivity and diagnostic accuracy were higher for FE(NO) measurement (77%; area under the receiver operating curve [AUC], 0.8) than for spirometry (22%; AUC, 0.63). The sensitivity and specificity of Eos% in induced sputum were 40% and 82%, respectively, and the diagnostic accuracy of Eos% was lower (AUC, 0.58). When both inflammatory biomarkers were used together specificity increased to 76%. CONCLUSIONS: The diagnostic accuracy of FE(NO) measurement was superior to that of the standard diagnostic spirometry in patients with symptoms suggestive of asthma. The use of FE(NO) measurement and induced sputum Eos% together to diagnose asthma in clinical practice is more accurate than spirometry or FE(NO) assessment alone and easier to perform.

[Monitoring of breathing pattern at rest by electrical impedance tomography]. / Seguimiento del patrón ventilatorio en reposo mediante tomografía por impedancia eléctrica.

OBJECTIVE: Electrical impedance tomography (EIT) involves the application of a small alternating current to produce a series of chest images that can be used to monitor breathing pattern. The relation between chest images and tidal volume has not been sufficiently validated. The aim of the present study was to analyze the correlation between EIT images and the volume-time signal measured with a pneumotachometer in 13 healthy volunteers. MATERIAL AND METHODS: The following measurement devices were used: a) MedGraphics preVent Pneumotach, with special software for recording the volume-time signal (reference test), and b) EIT-4, a fourth-generation prototype unit designed by the Department of Electronic Engineering at the Universidad Politécnica de Cataluña, Spain that records the volume-time signal and produces a graphic depiction of a cross section of the thorax at the sixth intercostal space. RESULTS: The mean (SD) tidal volume measured by the pneumotachometer and the EIT-4 was 0.523 (0.102) L and 0.527 (0.106) L, respectively (P value not significant). The linear correlation coefficient between the 2 measurements was 0.923 (P=.001), and the mean of the differences between the 2 procedures was -0.003 L (95% confidence interval, -0.045 to 0.038). The greatest differences were associated with female gender, body mass index, and chest circumference. In view of these differences, a different equation based on these variables was needed for calibration of the EIT-4. CONCLUSIONS: The EIT-4 provides an alternative means of monitoring breathing pattern, although a number of issues related to the circumference of the rib cage need to be resolved.

Seguimiento del patrón ventilatorio en reposo mediante tomografía por impedancia eléctrica / Monitoring of breathing pattern at rest by electrical impedance tomography

Objetivo: La tomografía por impedancia eléctrica (TIE) permite realizar un seguimiento del patrón ventilatorio a partir de una secuencia de imágenes torácicas obtenidas por la captación de una corriente alterna de baja intensidad. La relación entre las imágenes torácicas y el volumen circulante no está suficientemente validada. El propósito del presente estudio ha sido comparar, en un grupo de 13 voluntarios sanos, la correspondencia entre las imágenes de la TIE y la señal volumen/tiempo obtenida mediante un neumotacómetro. Material y métodos: Los equipos que se utilizaron para las mediciones fueron: a) MedGraphics prevent TM™ Pneumotach, implementando el software adecuado para registrar las señales volumen/tiempo (prueba de referencia), y b) TIE-4, cuarta versión de un equipo diseñado por el Departamento de Ingeniería Electrónica de la Universidad Politécnica de Cataluña, que permite tanto el registro de la señal volumen/tiempo como una representación gráfica de la sección transversal situada en el sexto espacio intercostal. Resultados: La media ± desviación estándar de volumen circulante obtenida mediante el neumotacómetro fue de 0,523 ± 0,102 l, y con la TIE-4, de 0,527 ± 0,106 l (p no significativa). El coeficiente de correlación lineal entre ambas determinaciones fue de 0,923 (p = 0,001). La media de las diferencias entre ambos procedimientos fue de -­0,003 l (intervalo de confianza del 95%, ­-0,045 a 0,038). Las mayores diferencias estaban relacionadas con el sexo femenino, el índice de masa corporal y el contorno torácico, lo que obligó a una ecuación diferente para calibrar la TIE-4 en función de estas variables. Conclusiones: La TIE-4 se presenta como un método alternativo para realizar el seguimiento del patrón ventilatorio, aunque deben resolverse aspectos relacionados con la conformación de la caja torácica

Objective: Electrical impedance tomography (EIT) involves the application of a small alternating current to produce a series of chest images that can be used to monitor breathing pattern. The relation between chest images and tidal volume has not been sufficiently validated. The aim of the present study was to analyze the correlation between EIT images and the volume­time signal measured with a pneumotachometer in 13 healthy volunteers. Material and Methods: The following measurement devices were used: a) MedGraphics preVent™ Pneumotach, with special software for recording the volume­time signal (reference test), and b) EIT-4, a fourth-generation prototype unit designed by the Department of Electronic Engineering at the Universidad Politécnica de Cataluña, Spain that records the volume­time signal and produces a graphic depiction of a cross section of the thorax at the sixth intercostal space. Results: The mean (SD) tidal volume measured by the pneumotachometer and the EIT-4 was 0.523 (0.102) L and 0.527 (0.106) L, respectively (P value not significant). The linear correlation coefficient between the 2 measurements was 0.923 (P=.001), and the mean of the differences between the 2 procedures was ­-0.003 L (95% confidence interval, -­0.045 to 0.038). The greatest differences were associated with female gender, body mass index, and chest circumference. In view of these differences, a different equation based on these variables was needed for calibration of the EIT-4. Conclusions: The EIT-4 provides an alternative means of monitoring breathing pattern, although a number of issues related to the circumference of the rib cage need to be resolved

[Measurement of fraction of exhaled nitric oxide with the portable NIOX-MINO monitor in healthy adults]. / Determinación de óxido nítrico en aire espirado (FENO).

Measurement of the fraction of exhaled nitric oxide (FENO) provides a noninvasive way to monitor asthma treatment in clinical practice. The aim of this study was to determine FENO reference values for measurements recorded with the portable NIOX MINO monitor in a group of healthy volunteers. We also assessed the association between values recorded by the portable monitor and the N-6008 chemiluminescence analyzer used in our pulmonary function laboratory. The FENO values obtained with the portable monitor were consistently higher than those recorded by the N-6008 analyzer; the cutoff value for the portable monitor was 34 ppb (mean + 2 SD). We detected a direct correlation (r=0.92) between the FENO measurements recorded by the 2 monitors (P=.001). The following equation expresses the relationship between measurements from the 2 devices: FENO(NIOX MINO) = 10 + [1.5 FENO(N-6008)]. We did not observe statistically significant correlations between FENO measurements and age, sex, body mass index, or spirometry.

Determinación de óxido nítrico en aire espirado (FENO) mediante un equipo portátil (NIOX-MINO® Aerocrine) en población sana / Measurement of fraction of exhaled nitric oxide with the portable NIOX-MINO monitor in healthy adults

La determinación de óxido nítrico en aire espirado (FENO) es una técnica no invasiva que se utiliza en la evaluación clínica y el tratamiento del asma. El objetivo de este estudio ha sido determinar los valores de referencia de FENO en un grupo de voluntarios sanos mediante la utilización de un nuevo equipo portátil (NIOX-MINO® Aerocrine), así como determinar el grado de relación que presenta con el equipo de determinación habitual en nuestro laboratorio de función pulmonar (sensor de quimioluminiscencia N-6008® SIR). Según los resultados obtenidos, los valores de FENO que da el equipo portátil son siempre superiores a los que ofrece el sensor habitual, con un valor de corte de 34 ppb (media + 2 desviación estándar). Existe un relación directa y significativa de la determinación de FENO entre ambos equipos (r = 0,92; p = 0,001) con un factor de corrección de: FENO (NIOX-MINO®) = 10 + 1,5 FENO (N-6008®). La relación entre los valores de FENO y la edad, el sexo, el índice de masa corporal y los valores espirométricos no fue estadísticamente significativa

Measurement of the fraction of exhaled nitric oxide (FENO) provides a noninvasive way to monitor asthma treatment in clinical practice. The aim of this study was to determine FENO reference values for measurements recorded with the portable NIOX MINO monitor in a group of healthy volunteers. We also assessed the association between values recorded by the portable monitor and the N-6008 chemiluminescence analyzer used in our pulmonary function laboratory. The FENO values obtained with the portable monitor were consistently higher than those recorded by the N-6008 analyzer; the cutoff value for the portable monitor was 34 ppb (mean + 2 SD). We detected a direct correlation (r=0.92) between the FENO measurements recorded by the 2 monitors (P=.001). The following equation expresses the relationship between measurements from the 2 devices: FENO(NIOX MINO) = 10 + [1.5 FENO(N-6008)]. We did not observe statistically significant correlations between FENO measurements and age, sex, body mass index, or spirometry

Use of electrical impedance tomography (EIT) for the assessment of unilateral pulmonary function.

We describe a fully automatable quantification process for the assessment of unilateral pulmonary function (UPF) by means of EIT and propose a measurement protocol for its clinical implementation. Measurements were performed at the fourth and sixth intercostal levels on a first group of ten healthy subjects (5M, 5F, ages 26-48 years) to define the proper protocol by evaluating the most common postures and ventilation modes. Several off-line processing tools were also evaluated, including the use of digital filters to extract the respiratory components from EIT time series. Comparative measures were then carried out on a second group consisting of five preoperatory patients with lung cancer (4M, IF, ages 25-77 years) scheduled for radionuclide scanning. Results show that measurements were best performed with the subject sitting down, holding his arms up and breathing spontaneously. As regards data processing, it is best to extract Fourier respiratory components. The mean of the healthy subject group leads to a left-right division of lung ventilation consistent with literature values (47% left lung, 53% right lung). The comparative study indicates a good correlation (r = 0.96) between the two techniques, with a mean difference of (-0.4+/-5.4)%, suggesting that the elimination of cardiac components from the thoracic transimpedance signal leads to a better estimation of UPF.