The early life origins of chronic pulmonary diseases are thought to arise in peripheral small airways. Predictors of ventilation inhomogeneity, a proxy of peripheral airway function, are understudied ...in schoolchildren.
Is the double-tracer gas single-breath washout (DTG-SBW) measurement feasible in a pediatric field study setting? What are the predictors of the DTG-SBW-derived ventilation inhomogeneity estimate in unselected schoolchildren?
In this prospective cross-sectional field study, a mobile lung function testing unit visited participating schools in Switzerland. We applied DTG-SBW, fraction of exhaled nitric oxide (Feno), and spirometry measurements. The DTG-SBW is based on tidal inhalation of helium and sulfur-hexafluoride, and the phase III slope (SIIIHe-SF6) is derived. We assessed feasibility, repeatability, and associations of SIIIHe-SF6 with the potential predictors of anthropometrics, presence of wheeze (ie, parental report of one or more episode of wheeze in the prior year), Feno, FEV1, and FEV1/FVC.
In 1,782 children, 5,223 DTG-SBW trials were obtained. The DTG-SBW was acceptable in 1,449 children (81.3%); the coefficient of variation was 39.8%. SIIIHe-SF6 was independently but weakly positively associated with age and BMI. In 276 children (21.2%), wheeze was reported. SIIIHe-SF6 was higher by 0.049 g.mol.L−1 in children with wheeze compared with those without and remained associated with wheeze after adjusting for age and BMI in a multivariable linear regression model. SIIIHe-SF6 was not associated with Feno, FEV1, and FEV1/FVC.
The DTG-SBW is feasible in a pediatric field study setting. On the population level, age, body composition, and wheeze are independent predictors of peripheral airway function in unselected schoolchildren. The variation of the DTG-SBW possibly constrains its current applicability on the individual level.
ClinicalTrials.gov; No.: NCT03659838; URL: www.clinicaltrials.gov
Display omitted
The problem of ventilation efficiency after total laser arytenoidectomy with posterior cordectomy due to bilateral vocal cord paralysis is discussed. There are a number of views on the usefulness and ...efficacy of different surgical procedures aimed at widening the glottis, but the studies concerning the long-term functional results are still lacking. The objective of the study is to evaluate the durability of ventilation results in patients after laser arytenoidectomy with posterior cordectomy based on the comparison between the early postoperative results and those assessed after a period of 5 years. Thirty patients (24 females, 6 males) aged between 30 and 80 (mean 58.5) with bilateral vocal cord paralysis after thyroid surgery, who underwent laser arytenoidectomy with posterior cordectomy, were analyzed. Ventilation tests were performed immediately after the operation and 5 years later with Body-Master Laab (Jaeger). The actual and predicted values of FVC, FEF(25), FEF(50), FEF(75), PEF, MMEF(75/25), AREA(Ex), sR(T0T), R(T0T) were compared and analyzed. Also, the values of the inspiratory parameters FIV(1), FIF(50), PIF and the coefficients FEF(50)/FIF(50) and FIV(1)/FEV(1) were assessed. Moreover, subjective evaluation was performed based on a questionnaire. The statistical analysis reveals a significant decrease in FIV(1), FIF(50), PIF and FIV(1)/FEV(1). FEF(50)/FIF(50) and sR(T0T) (actual and predicted values) increased significantly after 5 years from the operation. However, the patients did not complain nor was this tendency reflected in their answers to the questionnaire. The probable reasons for such ventilation results are discussed. The role of phoniatric rehabilitation and the time elapsed is emphasized. In general, it can be concluded that laser arytenoidectomy with posterior cordectomy is a durable and effective procedure, although the objective assessment does not fully match the patient's subjective impression.
There is confusion in the literature concerning the physiology and pathology of the nasal valve, and some debate as to whether there is one valve or two. In an attempt to clarify these uncertainties ...we have measured nasal function by assessing nasal minimum cross-sectional area, inspiratory resistance and peak inspiratory flow under baseline conditions and after the application of a topical vasoconstrictor. These measurements were then repeated following the application of external and internal nasal splints. Whatever test was employed the results showed that vasoconstriction tended to be the most potent stimulus which changed nasal function producing significant expansion of the minimum cross-sectional area, a decrease in inspiratory resistance and an increase in peak inspiratory flow. External splints also increased the minimal cross sectional area but they had no effect on inspiratory resistance or on the tendency of the vestibular rim to collapse at high inspiratory flow rates. The tendency for lower lateral cartilage collapse was, however, prevented by internal splintage using alar dilators. The results of this study suggest that there is an internal valve at the nasal isthmus where the principal alterations in airway patency follow changes in mucosal congestion, and a mobile external valve where airflow is limited by the tendency of the alar cartilages to collapse. These should be considered as separate entities with differing pathophysiology and these differences should be taken into account when treating patients with airway obstruction due to pathology at these sites.
From 1962 to 1988, 147 neonates were admitted for operative repair of CDH to the Division of Pediatric Surgery in the Children's Hospital of Cologne. Follow-up studies were performed on 45 patients ...ages 1 to 25 years representing 54.2% of the 83 survivors. 18 patients (40%) were entirely without any complaints, 11 patients (24.4%) had increased rates of respiratory infections. Especially in early childhood they suffered from obstructive alterations in the respiratory tract. No restrictive pulmonary changes were observed. Scintigraphic ventilation tests were performed on 44 cases. 34 (77%) tests indicated absolutely normal results. Some rare local deficits of lung ventilation were based on adhesive anatomic alterations of the thoracic skeleton and the diaphragm. The lung function tests conducted in 29 persons ages 6 to 25 years revealed that the vital capacity and the forced expiratory volume were all normal. We found an increase of the intrathoracic gas volume in 11 infants (disposition to pulmonary inflation). In 9 cases we observed a decrease in the mid expiratory flow curves and in 6 patients we measured an increase in the specific resistance of airways (tendency towards obstructive airway alterations). Nevertheless even former hypoplastic lungs revealed a good extensibility.
It is critical to identify patients whose intubation will be difficult to ensure that necessary precautions are taken. In this study, we aimed to show the power of almost all tests used to predict ...difficult endotracheal intubation (DEI), and to determine which test are more accurate for this purpose.
This observational study conducted between May 2015 and January 2016 at department of anesthesiology of a tertiary hospital in Turkey (n=501). A total of 25 parameters and 22 tests used for DEI were compared according to groups formed according to the Cormack-Lehane classification (gold standard).
The mean age was 49.83±14.00 years, and 259 (51.70%) patients were males. We found difficult intubation frequency to be 7.58%. Mallampati classification, atlanto-occipital joint movement test (AOJMT), upper lip bite test, mandibulohyoid distance (MHD), maxillopharyngeal angle, height-to-thyromental distance ratio, and mask ventilation test were independently associated with difficult intubation.
Despite comparing 22 tests, the results obtained in this study cannot definitively identify any single test that pre-dicts difficult intubation. Nonetheless, our results show that MHD (high sensitivity and negative predictive value) and AOJMT (high specificity and positive predictive value) are the most useful tests to predict difficult intubation.
Road tunnels are equipped with various safety installations that enable the tunnel’s autonomous response to fire in order to ensure conditions suitable for safe self-rescue and evacuation. A key role ...in this effort is played by the monitoring of the longitudinal airflow velocity and its regulation. This study contributes to validation of the Fire Dynamics Simulator (FDS 6) capabilities to model tunnel airflow generated by emergency ventilation. A previous study, in which an FDS 6 model of a real 900 m long motorway tunnel was developed and validated by a full-scale ventilation test, pointed to the relatively high inaccuracies of the average steady-state airflow velocity generated by ventilation measured by tunnel anemometers (13%, 17% and 14% for three ventilation modes). In this paper, it is shown that the application of a modified evaluation procedure and improving the representation of tunnel anemometers leads to the significant improvement of simulation results with inaccuracies of 5%, 1% and 3% for the considered ventilation modes. The observed inaccuracies are even comparable to the measurement accuracy of the tunnel anemometers. A further extension of the modeling of the steady-state airflow velocity generated by emergency ventilation measured by the used anemometers is also described.
The ventilation effect has a direct influence on the efficiency and security of the construction of an underground cavern group. Traditional forced ventilation schemes may be ineffective and result ...in resource wastage. Based on the construction ventilation of the Jinzhou underground oil storage project, an axial flow gallery ventilation mode using shafts as the fresh air inlet was proposed. A 3D steady RANS (Reynolds Averaged Navier-Stokes) approach with the RNG (Renormalization-group) k-ε turbulence model was used to study airflow behavior and hazardous gas dispersion when different ventilation schemes were employed. Field test values of the air velocity and CO concentration in the main cavern and construction roadway were also adopted to validate the RNG k-ε turbulence model. The results showed that the axial flow gallery ventilation mode can ensure that the direction of air flow is the same as that of heavy trucks, fresh air is always near the excavation face, and the disturbance of the construction process is greatly reduced. The scheme is suitable for large-scale caverns with a ventilation distance less than 2 km, and an intermediate construction shaft is not needed. When the ventilation distance exceeds 2 km, it is possible to use jet fans to assist the axial flow gallery ventilation mode or to completely adopt jet-flow gallery ventilation.
In the spring semester of 2020, many universities are believed to have abandoned practical classes in physical education due to the pandemic of the SARS-CoV-2. This document introduces the methods of ...practical classe implemented by Aichi University of the Arts in the spring semester of 2020. The number of students in each class was reduced to twenty. The gymnasium was tested for ventilation using a smoke machine. To ensure social distancing, markers were placed on the floor of the gymnasium at two-meter intervals. The gymnasium floor was divided into two areas, belongings area in the front and exercise area in the back of gymnasium, with all doors fully open and the circulator installed on the floor running towards the doors. To avoid crowding in the locker room, the course students’ travel routes were dispersed in two directions. Teachers and students were required to wear masks from before entering the gym until they left. During the barre lessons, disposable gloves were worn by all participants, and they were all facing the same direction at least one-meter interval. The bar was disinfected with alcohol after the bar lesson and the floor was mopped entirely after the class. If practical class are not possible in the future, the pedagogical content that would be possible in the assigned classes needs to be devised and its pedagogical quality tested.
Status of JEM ECLSS Design Suzuki, Tadashi; Uda, Akira; Hattori, Akira ...
Eco-Engineering,
1991, Letnik:
4, Številka:
1
Journal Article
Odprti dostop
The preliminary design of the Japanese Experiment Module (JEM) started in January 1990, and the first and second interim design reviews were held in July 1990 and February 1991 respectively. As a ...result of the JEM configuration review activity and the technical interface coordination with NASA through the Environmental Control and Life Support System (ECLSS) working group meetings, a part of the JEM ECLSS function was changed. This paper presents the JEM ECLSS baseline and the subsystem configuration at the second interim design review. Also the outline of the preliminary cabin air ventilation testing which was conducted from 1989 to 1990 is described.
PDF
