Effects of the intermittent intrapulmonary deflation technique on expiratory flow limitation: an in vitro study.

INTRODUCTION: The intermittent intrapulmonary deflation (IID) technique is a recent airway clearance technique that intends to delay the onset of expiratory flow limitation (EFL) during exhalation. We showed in a previous study that IID increased the expiratory volume of COPD patients compared to quiet breathing and positive expiratory pressure (PEP) therapy. We hypothesized that it was due to the attenuation of the EFL. OBJECTIVES: To verify the physiologic effects of IID and PEP techniques on EFL with a mechanical lung model. METHODS: A mechanical lung model was created to assess the effects of IID and PEP techniques. The thorax was simulated by a plexiglas box in which an adult test lung was connected. A calibration syringe simulated the inspiratory phase. Later, with activation of the IID, the expiratory phase was driven by the deflation generated by the device. With PEP, the expiration occurred maintaining an expiratory pressure between 5 and 10 cmH2O. A pneumotachograph and a pressure transducer were placed in series for flow, volumes and pressure measurements. RESULTS: The model reproduced physiological characteristics of EFL. However, the deflation of the model was slowed by IID and PEP, and flow remained almost constant, so flow limitation was reduced. CONCLUSION: The IID and PEP attenuate EFL and increase exhaled volume in the in vitro model.

Short-Term Effect of Intermittent Intrapulmonary Deflation on Air Trapping in Patients With COPD.

BACKGROUND: Intermittent intrapulmonary deflation is an airway clearance technique that generates negative pressure during expiratory phases. This technology is intended to reduce air trapping by delaying the onset of air-flow limitation during exhalation. The objective of this study was to compare the short-term effect of intermittent intrapulmonary deflation versus positive expiratory pressure (PEP) therapy on trapped gas volume and vital capacity (VC) in patients with COPD. METHODS: We designed a randomized crossover study in which the participants with COPD received a 20-min session of both intermittent intrapulmonary deflation and PEP therapy on separate days and in random order. Lung volumes were measured via body plethysmography and helium dilution techniques, and spirometric outcomes were reviewed before and after each therapy. The trapped gas volume was estimated via functional residual capacity (FRC), residual volume (RV), and by the difference between FRC obtained through body plethysmography and helium dilution. Each participant also performed 3 VC maneuvers, from total lung capacity to RV with both devices. RESULTS: Twenty participants with COPD (mean ± SD ages 67 ± 8 y; FEV1 48.1 ± 17.0%) were recruited. There was no difference between the devices in FRC or trapped gas volume. However, the RV decreased more during intermittent intrapulmonary deflation compared with PEP. The intermittent intrapulmonary deflation mobilized a larger expiratory volume than PEP during the VC maneuver (mean difference 389 mL, 95% CI 128-650 mL; P = .003). CONCLUSIONS: The RV decreased after intermittent intrapulmonary deflation compared with PEP, but this effect was not captured by other estimates of hyperinflation. Although the expiratory volume obtained during the VC maneuver with intermittent intrapulmonary deflation was greater than that obtained with PEP, the clinical importance as well as the long-term effects remain to be determined.(ClinicalTrials.gov registration NCT04157972.).

The effect of tongue elevation muscle training in patients with obstructive sleep apnea: A randomised controlled trial.

BACKGROUND: Oropharyngeal myofunctional therapy is a multi-component therapy effective to reduce the severity of obstructive sleep apnoea (OSA). However, existing protocols are difficult to replicate in the clinical setting. There is a need to isolate the specific effectiveness of each component of the therapy. OBJECTIVE: To assess the effects of a 6 weeks tongue elevation training programme in patients with OSA. METHODS: We conducted a multicentre randomised controlled trial. Eligible participants were adults diagnosed with moderate OSA who presented low adherence to continuous positive airway pressure therapy (mean use <4 h per night). The intervention group completed a 6 weeks tongue elevation training protocol that consisted in anterior tongue elevation strength and endurance tasks with the Iowa Oral Performance Instrument. The control group completed a 6 weeks sham training protocol that involved expiratory muscle training at very low intensity. Polygraphy data, tongue force and endurance, and OSA symptoms were evaluated pre- and post-intervention. The primary outcome was apneoa-hypopnea index (AHI). RESULTS: Twenty-seven patients (55 ± 11 years) were recruited. According to modified intention-to-treat analysis (n = 25), changes in AHI and c did not significantly differ between groups. Daytime sleepiness (Epworth Sleepiness Scale) and tongue endurance significantly improved in the intervention group compared to the control group (p = .015 and .022, respectively). In the intervention group, 75% of participants had a decrease in daytime sleepiness that exceeded the minimal clinically important difference. CONCLUSION: Six weeks of tongue elevation muscle training had no effect on OSA severity.

Telerehabilitation as a Form of Pulmonary Rehabilitation in Chronic Lung Disease: A Systematic Review.

INTRODUCTION: Tele-rehabilitation is increasingly used to deliver pulmonary rehabilitation. The aim of this systematic review was to compare the effect between tele-pulmonary rehabilitation and classical supervised pulmonary rehabilitation. METHOD: Three databases were analysed (PubMed, PEDro, Scopus). The selection and evaluation of studies followed the PRISMA guidelines. The risk of bias was evaluated using the PEDro Scale. RESULTS: From the initial selection (n = 245), ten studies were retrieved, including from 10 to 67 patients. All but two (IPF) included patients with COPD. Based on the FEV1, patients with COPD were mainly categorised as moderate and severe. The teleactivities were heterogenous in terms of proposed exercises and way of settings and often not in agreement with the guidelines about pulmonary rehabilitation. Despite this, the effects of the interventions were globally positive on functional exercise capacity, quality of life, anxiety and depression, and impact of COPD on personal life but not on dyspnoea. The PEDro scores varied from 4 to 8. The adherence was higher than 80% when supervision during the exercise was included. CONCLUSION: This review demonstrated that the telerehabilitation is safe and well accepted by the patients, and could be considered as one option of classical pulmonary rehabilitation to improve the functional exercise capacity, quality of life, anxiety and depression, and the impact of COPD on personal's life. This conclusion cannot be extrapolated to the other chronic lung diseases due to the lack of data.

Systems on Top of Nasal Cannula Improve Oxygen Delivery in Patients with COVID-19: a Randomized Controlled Trial.

BACKGROUND: Treating hypoxemia while meeting the soaring demands of oxygen can be a challenge during the COVID-19 pandemic. OBJECTIVE: To determine the efficacy of the surgical facemask and the double-trunk mask on top of the low-flow oxygen nasal cannula on arterial partial pressure of oxygen (PaO2) in hypoxemic COVID-19 patients. DESIGN: Randomized controlled trial. PARTICIPANTS: Hospitalized adults with COVID-19 and hypoxemia treated with the low-flow nasal cannula were enrolled between November 13, 2020, and March 05, 2021. INTERVENTIONS: Patients were randomized in a 1:1:1 ratio to receive either the nasal cannula alone (control) or the nasal cannula covered by the surgical facemask or the double-trunk mask. Arterial blood gases were collected at baseline and 30 min after the use of each system. The oxygen output was adapted afterwards to retrieve the baseline pulse oxygen saturation. The final oxygen output value was recorded after another 30-min period. MAIN MEASURES: The primary outcome was the absolute change in PaO2. Secondary outcomes included changes in oxygen output, arterial partial pressure of carbon dioxide (PaCO2), vital parameters, and breathlessness. KEY RESULTS: Arterial blood samples were successfully collected in 24/27 (8 per group) randomized patients. Compared to the nasal cannula alone, PaO2 increased with the surgical facemask (mean change: 20 mmHg, 95% CI: 0.7-38.8; P = .04) and with the double-trunk mask (mean change: 40 mmHg; 95% CI: 21-59; P < .001). Oxygen output was reduced when adding the surgical facemask (median reduction: 1.5 L/min [95% CI: 0.5-4.5], P < .001) or the double-trunk mask (median reduction: 3.3 L/min [95% CI: 2-5], P < .001). The double-trunk mask was associated with a PaCO2 increase of 2.4 mmHg ([95% CI: 0-4.7], P = .049). Neither mask influenced vital parameters or breathlessness. CONCLUSIONS: The addition of the surgical facemask or the double-trunk mask above the nasal cannula improves arterial oxygenation and reduces oxygen consumption.

A distância entre o domicílio e o centro de reabilitação não influencia a adesão ao programa de reabilitação pulmonar: um estudo retrospectivo / Distance from home to rehabilitation center did not influence adherence to pulmonary rehabilitation program: a retrospective study

Background: Adherence to treatment is critical when dealing with chronic diseases. One of the difficulties in maintain long-term adherence is the distance from home to rehabilitation center. Objective: To determine the influence of the distance from subjects' residence to rehabilitation center on adherence of a 12-week pulmonary rehabilitation program in chronic respiratory disease. Methods: This retrospective study analyzed patients' medical records with chronic respiratory diseases from a pulmonary rehabilitation center. Driving distance between patients' home and rehabilitation center was calculated with Google maps. The home-rehabilitation center distances were classified in three levels: up to 10, 10-30 and more than 30 km. Results: 280 medical records from patients with chronic pulmonary diseases with medical indication to follow the pulmonary rehabilitation program were found and 148 medical records were included in our study. Out of them, the majority (n = 93) had chronic obstructive pulmonary disease (COPD). Seventy percent of patients lived up to 10 km, 24% lived between 10 and 30 km and 6% lived more than 30 km. No difference in adherence was found comparing the three groups based on the distance from home to rehabilitation center. Conclusion: In this study, distance between home and rehabilitation center did not influence adherence to pulmonary rehabilitation program. (AU)

European Survey: Dysphagia Management in Patients with Neuromuscular Diseases.

Dysphagia is common in patients with neuromuscular diseases (NMDs). Its management differs by country and clinical setting. The purpose of this study was to describe current practices in the management of dysphagia in NMDs across Europe. An online survey of sixteen questions was developed, including basic information on facilities, existence of a management protocol, availability of dedicated therapists, tools used during screening, assessment, treatment stages, and treatment strategies. The survey was rolled out to European healthcare facilities providing care for NMDs. A total of 140 facilities across 25 European countries completed the survey. Substantial discrepancies in dysphagia management were identified among respondents. Seventy-two percent of the facilities reported having a protocol for at least one of the three management stages whereas only 39% had one for all. Speech and language therapists were reported as involved throughout the entire management stage while participation of other members from multidisciplinary teams varied depending on the stage. Clinical swallowing assessment was the most frequently reported tool in the assessment and treatment stages. For screening, questionnaires were the most frequently used while instrumental examinations were mainly reported in the assessment stage. For the treatment stage, adaptation strategies (diet, food, and posture) were the most reported approaches. In conclusion, the survey highlighted the absence of a defined protocol concerning the management of dysphagia in most of the surveyed healthcare facilities. Standardized training strategies and guidelines are necessary in the future to familiarize clinicians with each stage of the management of dysphagia.

Follow-up of functional exercise capacity in patients with COVID-19: It is improved by telerehabilitation.

BACKGROUND: The impact of the COVID-19 pandemic on functional exercise capacity seemed quickly clinically evident. The objective of this study was to assess the functional exercise capacity of patients with severe COVID-19 and to evaluate the effect of a telerehabilitation program in the specific context of the COVID-19 pandemic. METHOD: Patients hospitalized for severe or critical COVID-19 were recruited. The functional exercise capacity (1-min sit-to-stand test (STST)) was prospectively quantified at discharge. A telerehabilitation program was then proposed. A control group was composed with the patients refusing the program. RESULTS: At discharge, none of the 48 recruited patients had a STST higher than the 50th percentile and 77% of them were below the 2.5th percentile. SpO2 was 92.6 ± 3.0% after STST and 15 patients had oxygen desaturation. After 3-months of follow-up, the number of repetitions during STST significantly increased either in telerehabilitation (n = 14) (p < 0.001) or in control groups (n = 13) (p = 0.002) but only one patient had a result higher than the 50th percentile (in Telerehabilitation group) and 37% of them were still under the 2.5th percentile for this result. The improvement was significantly and clinically greater after the telerehabilitation program (p = 0.005). No adverse events were reported by the patients during the program. CONCLUSIONS: Patients hospitalized for COVID-19 have a low functional exercise capacity at discharge and the recovery after three months is poor. The feasibility and the effect of a simple telerehabilitation program were verified, this program being able to substantially improve the functional recovery after three months.

Integrative respiratory follow-up of severe COVID-19 reveals common functional and lung imaging sequelae.

BACKGROUND: COVID-19 pandemic resulted in an unprecedented number of hospitalizations in general wards and intensive care units (ICU). Severe and critical COVID-19 patients suffer from extensive pneumonia; therefore, long-term respiratory sequelae may be expected. RESEARCH QUESTION: We conducted a cohort study to determine respiratory sequelae in patients with severe and critical COVID-19. We aimed at evaluating the proportion of patients with persisting respiratory symptoms and/or abnormalities in pulmonary function tests (PFT) or in lung imaging. STUDY DESIGN: and methods: This is a single center cohort study including COVID-19 survivors who underwent a three-month follow-up with clinical evaluation, PFT and lung high-resolution computed tomography (HRCT). All clinical, functional, and radiological data were centrally reviewed. Multiple linear regression analysis was performed to identify factors associated with residual lesions on HRCT. RESULTS: Full clinical evaluation, PFT and lung HRCT were available for central review in 126, 122 and 107 patients, respectively. At follow-up, 25% of patients complained from dyspnea and 35% from fatigue, lung diffusion capacity (DLCO) was decreased in 45%, 17% had HRCT abnormalities affecting more than 5% of their lung parenchyma while signs of fibrosis were found in 21%. In multiple linear regression model, number of days in ICU were related to the extent of persisting lesions on HRCT, while intubation was associated with signs of fibrosis at follow-up (P = 0.0005, Fisher's exact test). In contrast, the severity of lung imaging or PFT changes were not predictive of fatigue and dyspnea. INTERPRETATION: Although most hospitalized COVID-19 patients recover, a substantial proportion complains from persisting dyspnea and fatigue. Impairment of DLCO and signs suggestive of fibrosis are common but are not strictly related to long-lasting symptoms.

Screening for oropharyngeal dysphagia in adult patients with neuromuscular diseases using the Sydney Swallow Questionnaire.

INTRODUCTION/AIMS: Oropharyngeal dysphagia is common in patients with neuromuscular diseases (NMDs). Its early recognition is vital for proper management. We tested a large cohort of adult NMD patients for oropharyngeal dysphagia using the Sydney Swallow Questionnaire (SSQ). We also looked for possible differences in characteristics of oropharyngeal dysphagia in various NMD groups and diseases. Finally, we compared results of this screening with those from their corresponding medical records for eventual "clinical history" of dysphagia. METHODS: We asked patients to fill in the SSQ during follow-up outpatient visits at our neuromuscular reference center. A total score above the cutoff score of 118.5 out of 1700 was indicative of oropharyngeal dysphagia. RESULTS: Of the 304 adult patients assessed for eligibility, 201 NMD patients (96 women and 105 men, aged 49.0 ± 16.2 years) were included and tested in this study. Oropharyngeal dysphagia was detected in 45% of all the NMD patients when using the SSQ, whereas only 12% had a positive medical record for dysphagia. The median SSQ scores for patients with myotonic syndromes (including myotonic dystrophy type 1), with amyotrophic lateral sclerosis, and with facioscapulohumeral dystrophy were above the cutoff score. The SSQ scores obtained revealed distinct oropharyngeal dysphagia characteristics in the different NMD groups and diseases. DISCUSSION: The SSQ tests positively for oropharyngeal dysphagia in a higher proportion of NMD patients compared with their medical records. The distinct oropharyngeal dysphagia characteristics we revealed in different NMD groups and diseases may help to elaborate adapted clinical approaches in the management of oropharyngeal dysphagia.

Impact of an Improvised System on Preserving Oxygen Supplies in Patients With COVID-19 / Impacto de un sistema improvisado para conservar los suministros de oxígeno en pacientes con covid-19

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Chest Expansion and Lung Function for Healthy Subjects and Individuals With Pulmonary Disease.

BACKGROUND: The purposes of this study were to verify the correlation between chest expansion and lung function within a larger sample of subjects composed of both healthy subjects and subjects affected by pulmonary disease, and to verify the influence of age, body mass index, and gender on chest expansion. METHODS: Adults were recruited prospectively when they visited the lung function lab. Chest expansion was measured with a measuring tape at 2 different levels of the rib cage by 1 blinded examiner. Spirometry was performed for each subject. RESULTS: Data from 251 subjects between 18 and 88 y old were collected and analyzed. Among the analyzed subjects, mean upper and lower chest expansion were 4.82 ± 1.84 cm and 3.99 ± 2.15 cm, respectively. A significant but poor correlation was found between both chest expansion and all lung function parameters (total lung capacity, FVC, and FEV1) (P = .01). Negative significant correlations were found between chest expansion and age as well as body mass index. The difference in upper chest expansion between obese and nonobese subjects was not statistically significant, but the difference in lower chest expansion was significant for these 2 groups. Finally, upper and lower chest expansion were not different between males and females. CONCLUSIONS: Based on these results, one cannot validate the use of chest expansion measurement to define lung function. In centers that have easy access to more precise and complete methods to measure lung function, the measurement of chest expansion for diagnostic purposes seems to be archaic. Additionally, age and body mass index are 2 parameters that can influence chest expansion.

FEV1/FEV6 y FEV6 una alternativa para FEV1/FVC y FVC en la detección de obstrucción de vías respiratorias / FEV1/FEV6 and FEV6 an alternative for FEV1/FVC and FVC in the detection of airway obstruction

INTRODUCCIÓN: el objetivo de este estudio fue verificar si los puntos de corte fijos y el límite inferior de lo normal (LLN) para el volumen espiratorio forzado en un segundo (FEV1) y el volumen espiratorio forzado en 6 segundos (FEV6) FEV1/FEV6 y el FEV6 son una medida alternativa para el FEV1 y la capacidad vital forzada (FVC), FEV1/FVC y la FVC en la detección de la enfermedad pulmonar obstructiva crónica (EPOC), en una muestra de pacientes del oriente boliviano. MÉTODOS: se analizaron un total de 92 pruebas espirométricas, 66 varones y 26 mujeres con riesgo de EPOC. La población del estudio incluyó a residentes de la ciudad de Santa Cruz de la Sierra-Bolivia (ciudad cosmopolita) de 35 a 90 años de edad. RESULTADOS: la sensibilidad y la especificidad fueron del 97,0% y el 96,9%, respectivamente, cuando se compararon los valores de corte fijos de FEV1/FEV6 de 0,73 con los de FEV1/FVC < 0,7 como regla estándar, según las recomendaciones del global obstructive lung diseases (GOLD) para detectar la obstrucción de las vías respiratorias. La sensibilidad y la especificidad fueron de 93,4% y 81,2%, respectivamente, cuando el LLN de FEV1/FVC y FEV1/FEV6 fueron utilizados. CONCLUSIONES: en conclusión, el FEV6 es un sustituto válido de la CVF para detectar la obstrucción de las vías respiratorias, ya sea utilizando puntos de corte fijos o el LLN. Se necesitan más estudios para verificar estos resultados en una población más grande y para establecer los valores predictivos espirométricos locales.

INTRODUCTION: the aim of this study was to verify if fixed cut-off points and lower limit of normal (LLN) for forced expiratory volume in one second (FEV1)/FEV6 and FEV6 as an alternative for FEV1/forced vital capacity (FVC) and FVC are valid for the detection of obstructive lung disease in a sample of Bolivian subjects. METHODS: a total of 92 spirometric consecutive tests from subjects, 66 males and 26 females at risk for COPD were analyzed. The study population included residents of city Santa Cruz de la Sierra, (Bolivia) aged from 35 to 90 yrs., from various ethnical origins (cosmopolitan city). RESULTS: sensibility and specificity were 97.0% and 96.9%, respectively when fixed cut-off values of FEV1/FEV6 of 0.73 was compared to FEV1/FVC<0.7 as standard, according to GOLD recommendations to detect airway obstruction. Sensibility and specificity were 100% and 89.5%, respectively when LLN of FEV1/FVC and FEV1/FEV6 were used. CONCLUSIONS: in conclusion, FEV6 is a valid surrogate for FVC to detect airway obstruction, either using fixed cut-off points or LLN. Further study is needed to verify these results in a larger population and to establish local spirometric predicted values

Cheyne-Stokes respiration and cardiovascular oscillations ending abruptly when deploying transfemoral aortic valve.

A 86-yr-old man was referred for transfemoral aortic valve implantation. Transthoracic echocardiography revealed a severe stenosis (mean gradient: 58 mmHg, aortic valve area: 0.4 cm2), and after multidisciplinary discussion, the risk of surgery was judged too high (logistic Euroscore: 51%), and the patient was proposed for a transfemoral aortic valve implantation (TAVI). On arrival in the operating room, the patient, fully conscious, was noted to have Cheyne-Stokes breathing (CSB), which persisted after 40% oxygen administration. TAVI procedure was successful, and the CSB pattern was interrupted within 8 s. To the best of our knowledge, this report is the first to show an acute disappearance of CSB, occurring only seconds after TAVI and restoration of a normal hemodynamic situation. To explain such rapid changes in breathing pattern, we hypothesize a role played by the acute release of pulmonary hypertension and pulmonary volume overload.NEW & NOTEWORTHY Acute disappearance of Cheyne-Stokes breathing after transfemoral aortic valve implantation suggests a reflex pathway originating from the fall in pulmonary vessels congestion.

Comparison of 6 Oscillatory Positive Expiratory Pressure Devices During Active Expiratory Flow.

BACKGROUND: Air-flow oscillations generated by exhaling through oscillatory positive expiratory pressure (OPEP) devices favor airway clearance. Variations in mechanical properties between different devices may influence therapeutic efficacy. The objective of this study was to assess mechanical properties in vitro and to compare the performance of 6 OPEP devices at different resistance levels under active expiratory flow patterns. METHODS: 4 gravity-dependent OPEP devices (ie, Flutter, Gelomuc, Pari O-PEP, Shaker Medic Plus) and 2 gravity-independent OPEP devices (ie, Acapella Choice and Aerobika) were each tested at low, medium, and high resistance settings. All devices were independently connected to a pulmonary waveform generator that reproduced active exhalation flows. Expiratory flow-volume curves were retrieved from 4 subjects with different stages of obstruction severity and were scaled according to either peak expiratory flow (4, 6, and 8 L/s) or volumes (2, 3 and 4 L), thus amounting to 24 active exhalations. Resulting waveforms were divided into 4 parts and the 2 middle parts were used to extract the following mechanical data: positive expiratory pressure (PEP), maximum expiratory pressure (Ppeak), oscillation frequency, and flow oscillation amplitude. The percentage of tests achieving oscillation frequencies ≥ 12 Hz and PEP ≥ 10 cm H2O was calculated for each device. RESULTS: Mechanistic effects of the Acapella, Aerobika, and Shaker devices were not comparable. The Flutter, Gelomuc, and Pari devices behaved similarly and achieved more tests with optimum oscillation frequency and PEP values than the other devices. These 3 devices also produced the highest oscillation amplitudes at the low-resistance level, whereas the Aerobika elicited higher and consistent oscillation amplitudes at medium and high resistance settings. CONCLUSIONS: Operational parameters differed between and within devices, yet the Flutter, Gelomuc, and Pari devices were similar in many aspects. Therapeutic efficacy may depend on the selected OPEP device and set resistance.

Intrapulmonary percussive ventilation leading to 20-minutes breath-hold potentially useful for radiation treatments.

We developed a training protocol based on Intrapulmonary Percussive Ventilation in order to prolong breath-hold while nearly suppressing the thorax motion. This protocol allowed ten subjects to achieve a 20-minutes-breath-hold, while reducing the residual surface motion to 1 mm around its mean position for more than 95% of the breath-hold duration.

Targeted Lung Deposition From Nebulization Is Not Improved in the Lateral Decubitus Position in Healthy Volunteers.

BACKGROUND: Clinical benefits of inhaled therapies are related to the amount of drug deposited in the targeted area of the lung. Body positions that influence the distribution of lung ventilation should impact lung deposition of the nebulized drug. The aim of this study was to analyze the immediate effect of body position while the subject lies on his side (lateral decubitus) during nebulization on 3-dimensional total and regional lung deposition. METHODS: A randomized crossover trial was performed on healthy male volunteers without cardiovascular or pulmonary disease. A technetium-99m diethylenetriaminepentaacetic acid (99mTc-DTPA) solution (4 mL) was nebulized using an individual-controlled inhalation system in left lateral decubitus and sitting positions with a 96-h washout period (43 inspirations of 4 s [ie, drug delivered until second 3] with a tidal volume of 0.8 L and a low inspiratory flow (200 mL/s). Drug deposition was followed with the use of planar images and single-photon-emission computed tomography combined with low-resolution computed tomography. Total and regional depositions were the main outcomes. Penetration index was also considered. RESULTS: Six participants (26.8 ± 6.9 y old) were included. Total lung deposition tended to be higher in a sitting position than in a lateral decubitus position: 10.2 ± 0.9% of nominal dose (95% CI 9.1-11.3) vs 8.6 ± 1.4% of nominal dose (95% CI 6.8-10.4) (P = .09). The deposition was significantly reduced in the dependent (left) lung in the lateral decubitus position: 3.5 ± 0.7% of nominal dose (95% CI 2.6-4.3) vs 4.7 ± 0.3% of nominal dose (95% CI 4.3-5.0) (P = .03). Penetration index was only influenced by body position for the dependent (left) lung (P = .043). CONCLUSIONS: The total amount of drug delivered to the lungs during nebulization with an individual-controlled inhalation system tended to decrease when performed in the left lateral decubitus position. Moreover, contrary to the initial hypothesis, the deposition of particles in the dependent lung was not improved by the lateral decubitus position in this configuration. (ClinicalTrials.gov registration NCT02451501.).

Mechanically-assisted non-invasive ventilation: A step forward to modulate and to improve the reproducibility of breathing-related motion in radiation therapy.

BACKGROUND AND PURPOSE: When using highly conformal radiotherapy techniques, a stabilized breathing pattern could greatly benefit the treatment of mobile tumours. Therefore, we assessed the feasibility of Mechanically-assisted non-invasive ventilation (MANIV) on unsedated volunteers, and its ability to stabilize and modulate the breathing pattern over time. MATERIALS AND METHODS: Twelve healthy volunteers underwent 2 sessions of dynamic MRI under 4 ventilation modes: spontaneous breathing (SP), volume-controlled mode (VC) that imposes regular breathing in physiologic conditions, shallow-controlled mode (SH) that intends to lower amplitudes while increasing the breathing rate, and slow-controlled mode (SL) that mimics end-inspiratory breath-holds. The last 3 modes were achieved under respirator without sedation. The motion of the diaphragm was tracked along the breathing cycles on MRI images and expressed in position, breathing amplitude, and breathing period for intra- and inter-session analyses. In addition, end-inspiratory breath-hold duration and position stability were analysed during the SL mode. RESULTS: MANIV was well-tolerated by all volunteers, without adverse event. The MRI environment led to more discomfort than MANIV itself. Compared to SP, VC and SH modes improved the inter-session reproducibility of the amplitude (by 43% and 47% respectively) and significantly stabilized the intra- and inter-session breathing rate (p < 0.001). Compared to VC, SH mode significantly reduced the intra-session mean amplitude (36%) (p < 0.002), its variability (42%) (p < 0.001), and the intra-session baseline shift (26%) (p < 0.001). The SL mode achieved end-inspiratory plateaus lasting more than 10 s. CONCLUSION: MANIV offers exciting perspectives for motion management. It improves its intra- and inter-session reproducibility and should facilitate respiratory tracking, gating or margin techniques for both photon and proton treatments.