UNASSIGNED: The quality of the spirometry is estimated with criteria of acceptability and repeatability. The repeatability criteria accepted by consensus is < 0.150 L.
UNASSIGNED: To know the repeatability in quality A spirometry.
UNASSIGNED: Analytical cross-sectional design. The demographic variables and the 3 best spirometry curves with normal, suggestive of restriction and bronchial obstruction profiles were obtained from consecutive subjects of both genders from 18 to 80 years of age. The repeatability was analyzed with the mean difference (bias) and the intraclass correlation coefficient.
UNASSIGNED: 630 curves from 210 subjects were accepted. Group age 60 ± 15 years. Female predominance 113 (53.8%), occupation: domestic services 61 (29%), and diagnosed with chronic obstructive pulmonary disease: 70 (33.4%). The differences in the curves were < 0.150 L. The mean difference (bias) and the intraclass correlation coefficient (95% confidence interval, 95% CI) of the forced expiratory volume in the first second were 1 vs. 2 maneuver: -0.01 (0.13, -0.14), 0.997 (95% CI 0.996, 0.998); 2 vs. 3 maneuver: 0.00 (0.13, -0.13), 0.997 (95% CI 0.996, 0.998), and maneuver 1 vs. 3: -0.00 (0.16, -0.17), 0.995 (95% CI 0.994, 0.996). Forced vital capacity: 1 vs. 2 maneuver: -0.01 (0.17, -0.18), 0.996 (95% CI 0.995, 0.997); 2 vs. 3 maneuver: 0.01 (0.17, -0.16), 0.997 (95% CI 0.0.996, 0.998), and maneuver 1 vs. 3: -0.00 (0.18, -0.19), 0.996 (95% CI 0.995, 0.997).
UNASSIGNED: The repeatability obtained in spirometry with quality A validates the use of the repeatability criterion of 0.150 L.
UNASSIGNED: la calidad de la espirometría se estima con criterios de aceptabilidad y repetitividad. La repetitividad aceptada por consenso es < 0.150 L.
UNASSIGNED: conocer la repetitividad en espirometrías de calidad A.
UNASSIGNED: diseño transversal analítico. Se obtuvieron las variables demográficas y las 3 mejores curvas de espirometría con perfil normal, que sugiriera restricción y obstrucción bronquial de sujetos consecutivos de ambos géneros de 18 a 80 años. La repetitividad se analizó con la diferencia de medias (sesgo) y el coeficiente de correlación intraclase.
UNASSIGNED: se aceptaron 630 curvas de 210 sujetos. Edad grupal 60 ± 15 años. Predominio femenino 113 (53.8%), ocupación: servicios domésticos 61 (29%) y con enfermedad pulmonar obstructiva crónica 70 (33.4%). Las diferencias en las curvas fueron < 0.150 L. Las diferencias medias (sesgo) y el coeficiente de correlación intraclase (intervalo de confianza al 95%, IC 95%) del volumen espiratorio forzado en el primer segundo fueron: maniobra 1 frente a 2: −0.01 (0.13, −0.14), 0.997 (IC 95% 0.996, 0.998); maniobra 2 frente a 3: 0.00 (0.13, −0.13), 0.997 (IC 95% 0.996, 0.998), y maniobra 1 frente a 3: −0.00 (0.16, −0.17), 0.995 (IC 95% 0.994, 0.996). La capacidad vital forzada: maniobra 1 frente a 2: −0.01 (0.17, −0.18), 0.996 (IC 95% 0.995, 0.997); maniobra 2 frente a 3: 0.01 (0.17, −0.16), 0.997 (IC 95% 0.0.996, 0.998), y maniobra 1 frente a 3: −0.00 (0.18, −0.19), 0.996 (IC 95% 0.995, 0.997).
UNASSIGNED: la repetitividad obtenida en espirometrías con calidad A valida el uso del criterio de repetitividad de 0.150 L.

METHODS: Little is known about self-induced cognitive trance (SICT) on respiratory function. The aims of this prospective, single-center, non-randomized, open-label study of healthy volunteers, were to characterize spirometry changes during SICT, confirm the safety of this technique, and investigate the potential clinical benefits of SICT.
RESULTS: Nine people participated. There were no significant difference in FEV1 FVC or FEF 25-75 before, during, and after SICT. There were significant improvements in grip strength during SICT (+2.2 kg/5.7 %, p<0.05) and in self-efficacy score related to physical activity at the end of the trance. One participant had a significant worsening of FEV1 during SICT in the context of a recent upper airway infection.
CONCLUSIONS: SICT does not significantly modify spirometry data in healthy volunteers and can improve self-efficacy related to physical activity. SICT should probably be performed with caution during upper airway infections.

BACKGROUND: High-flow tracheal oxygen (HFTO) is being used as supportive therapy during weaning in tracheostomized patients difficult to wean from invasive mechanical ventilation. There is, however, no clinical evidence for such a strategy. Therefore, we conducted a systematic review to summarize studies evaluating the physiologic effects of HFTO during tracheostomy-facilitated weaning and to identify potential areas for future research in this field.
METHODS: Observational and interventional studies on critically ill subjects weaning from mechanical ventilation via tracheostomy published until December 22, 2022, were eligible. Studies on high-flow oxygen, only in children, non-human models or animals, on clinical outcome only, abstracts without full-text availability, case reports, and reviews were excluded. Main outcomes were end-expiratory lung volume (EELV) and tidal volume using electrical impedance tomography, respiratory effort assessed by esophageal manometry, work of breathing and neuroventilatory drive as assessed by electrical activity of the diaphragm (EAdi) signal, airway pressure (Paw), oxygenation (PaO2 /FIO2 or SpO2 /FIO2 ), breathing frequency, tidal volume, and PaCO2 .
RESULTS: In total, 1,327 references were identified, of which 5 were included. In all studies, HFTO was administered with flow 50 L/min and compared to conventional O2 therapy in a crossover design. The total average duration of invasive ventilation at time of measurements ranged from 11-27 d. In two studies, PaO2 /FIO2 and mean Paw were higher with HFTO. EELV, tidal volumes, esophageal pressure swings, and EAdi were similar during high-flow tracheal oxygen and conventional O2 therapy.
CONCLUSIONS: The main physiological effect of HFTO as compared to conventional O2 therapy in tracheostomized subjects weaning from mechanical ventilation was improved oxygenation that is probably flow-dependent. Respiratory effort, lung aeration, neuroventilatory drive, and ventilation were similar for HFTO and conventional O2 therapy. Future studies on HFTO should be performed early in the weaning process and should evaluate its effect on sputum clearance and patient-centered outcomes like dyspnea.

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BACKGROUND: Collagen XIII is a transmembrane collagen associated with neuromuscular junction development, and in humans its deficiency results in congenital myasthenic syndrome type 19 (CMS19), which leads to breathing difficulties. CMS19 patients usually have restricted lung capacity and one patient developed chronic lung disease. In single-cell RNA sequencing studies, collagen XIII has been identified as a marker for pulmonary lipofibroblasts, which have been implicated in the resolution of pulmonary fibrosis.
METHODS: We investigated the location and function of collagen XIII in the lung to understand the origin of pulmonary symptoms in human CMS19 patients. Additionally, we performed immunostainings on idiopathic pulmonary fibrosis (IPF) samples (N=5) and both normal and fibrotic mouse lung. To study whether the lack of collagen XIII predisposes to restrictive lung disease, we exposed Col13a1-modified mice to bleomycin-induced pulmonary fibrosis.
RESULTS: Apparently normal alveolar septum sections of IPF patients\' lungs stained faintly for collagen XIII, and its expression was pinpointed to the septal fibroblasts in the mouse lung. Lung capacity was increased in mice lacking collagen XIII by over 10%. In IPF samples, collagen XIII was expressed by basal epithelial cells, hyperplastic alveolar epithelial cells and stromal cells in fibrotic areas, but the development of pulmonary fibrosis was unaffected in collagen XIII-deficient mice.
CONCLUSIONS: Changes in mouse lung function appear to represent a myasthenic manifestation of collagen XIII deficiency. We suggest that respiratory muscle myasthenia is the primary cause of the breathing problems suffered by CMS19 patients in addition to skeletal deformities. Induction of collagen XIII expression in the IPF patients\' lungs warrants further studies to reveal collagen XIII-dependent disease mechanisms.

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The high-intensity low-frequency acoustic sources have essential applications in acoustic biological effects research, airport bird repelling, and boiler ash removal. However, generating high-intensity low-frequency acoustic waves in open space is difficult. In this paper, a low-frequency acoustic generator with a resonant cavity used to enhance the acoustic intensity in open space was developed, which is an aerodynamic acoustic generator to radiates a high-intensity acoustic wave of 52Hz. Some experiments were carried out to measure this generator\'s internal flow field and radiated acoustic field characteristics, including the propagation characteristics at 100m. The experimental results show that the resonant enhancement effect is presented near the predetermined resonance frequency, and the enhanced value is about 4dB. The acoustic intensity for 52Hz at 1m position is 124dB. By combining the Helmholtz resonator with the airflow modulator, the airflow resonance in the resonator enhances the air pressure pulsation inside the chamber and increases the disturbance of acoustic radiation to the air. So as to improve the sound intensity and radiation efficiency in the low-frequency range.