Quiet Breathing Research Articles

Potentiality of impulse oscillometry to evaluate bronchodilator reversibility in untreated adult patients with newly diagnosed asthma.

Identifying positive bronchodilator reversibility (BDR) helps the diagnosis of asthma. However, not all patients can adequately perform the forced expiration during the spirometry test. An alternative test is required. Impulse oscillometry (IOS) is an effort-independent technique that enables the measurement of lung mechanics during quiet tidal breathing. We investigated the potentiality of IOS to evaluate BDR in untreated adult patients with newly diagnosed asthma (UAPNDS). All UAPNDS (aged 20-80 years) who never smoke and underwent IOS and spirometry before and after salbutamol inhalation at their initial visit to the hospital from March 22, 2017, to December 31, 2019, were identified. A total of 323 patients were enrolled. Data from the medical record, including demographic characteristics, laboratory examination, spirometric data, and IOS parameters, were retrospectively reviewed. The associations of parameters with the positive BDR and the performance of parameters in predicting the positive BDR were evaluated by statistical methods. Patients (n = 323) had a median age of 64 years and were mostly female (67.5%). Several variables, including serum total immunoglobulin level, blood eosinophil counts, blood eosinophil percentage (%), and two IOS parameters, were found to be different between the positive (n = 93) and negative BDR (n = 230) groups. Multivariate logistic regression analyses after adjustment by cofactors revealed that the percentage change of the area under the reactance curve between 5 Hz and resonant frequency [ΔAx (%)] after salbutamol inhalation was the only independent factor for the positive BDR. The area under the receiver operating characteristic curve of ΔAx (%) in predicting the positive BDR was 0.614 ( p = 0.0013), and its optimal cutoff value was -53.8% (sensitivity, 39.78% and specificity, 80.43%). In addition to spirometry, ΔAx (%), an IOS parameter, may serve as a novel indicator to evaluate BDR in UAPNDS.

Effects of C2 hemisection on respiratory and cardiovascular functions in rats.

High cervical spinal cord injuries induce permanent neuromotor and autonomic deficits. These injuries impact both central respiratory and cardiovascular functions through modulation of the sympathetic nervous system. So far, cardiovascular studies have focused on models of complete contusion or transection at the lower cervical and thoracic levels and diaphragm activity evaluations using invasive methods. The present study aimed to evaluate the impact of C2 hemisection on different parameters representing vital functions (i.e., respiratory function, cardiovascular, and renal filtration parameters) at the moment of injury and 7 days post-injury in rats. No ventilatory parameters evaluated by plethysmography were impacted during quiet breathing after 7 days post-injury, whereas permanent diaphragm hemiplegia was observed by ultrasound and confirmed by diaphragmatic electromyography in anesthetized rats. Interestingly, the mean arterial pressure was reduced immediately after C2 hemisection, with complete compensation at 7 days post-injury. Renal filtration was unaffected at 7 days post-injury; however, remnant systolic dysfunction characterized by a reduced left ventricular ejection fraction persisted at 7 days post-injury. Taken together, these results demonstrated that following C2 hemisection, diaphragm activity and systolic function are impacted up to 7 days post-injury, whereas the respiratory and cardiovascular systems display vast adaptation to maintain ventilatory parameters and blood pressure homeostasis, with the latter likely sustained by the remaining descending sympathetic inputs spared by the initial injury. A better broad characterization of the physiopathology of high cervical spinal cord injuries covering a longer time period post-injury could be beneficial for understanding evaluations of putative therapeutics to further increase cardiorespiratory recovery.

Diaphragmatic excursion by ultrasound: reference values for the normal population; a cross-sectional study in Egypt.

BackgroundMeasurement of diaphragmatic motion by ultrasound is being utilized in different aspects of clinical practice. Defining reference values of the diaphragmatic excursion is important to identify those with diaphragmatic motion abnormalities. This study aimed to define the normal range of diaphragmatic motion (reference values) by Mmode ultrasound for the normal population.MethodsHealthy volunteers were included in this study. Those with comorbidities, skeletal deformity, acute or chronic respiratory illness were excluded. Diaphragmatic ultrasound in the supine position was performed using a lowfrequency probe. The B-mode was applied for diaphragmatic identification, and the M-mode was employed for the recording of the amplitude of diaphragm contraction during quiet breathing, deep breathing and sniffing.ResultsThe study included 757 healthy subjects [478 men (63.14%) and 279 women (36.86%)] with normal spirometry and negative history of previous or current respiratory illness. Their mean age and BMI were 45.17 ±14.84 years and 29.36±19.68 (kg/m2). The mean right hemidiaphragmatic excursion was 2.32±0.54, 5.54±1.26 and 2.90±0.63 for quiet breathing, deep breathing and sniffing, respectively, while the left hemidiaphragmatic excursion was 2.35±0.54, 5.30±1.21 and 2.97±0.56 cm for quiet breathing, deep breathing and sniffing, respectively. There was a statistically significant difference between right and left diaphragmatic excursion among all studied subjects. The ratio of right to left diaphragmatic excursion during quiet breathing was (1.009±0.19); maximum 181% and minimum 28%. Only 19 cases showed a right to left ratio of less than 50% (5 men and 14 women). The diaphragmatic excursion was higher in males than females. There was a significant difference in diaphragmatic excursion among age groups. Age, sex and BMI significantly affected the diaphragmatic motion.ConclusionsDiaphragmatic excursion values presented in this study can be used as reference values to detect diaphragmatic dysfunction in clinical practice. Diaphragmatic motion is affected by several factors including age, sex and body mass index.

Assessment of role of MRI in the evaluation of spinal trauma

A total of 100 patients were analysed. Complete demographic and clinical details of all the patients were obtained. The source of data for this study was patients referred to Department of Radio diagnosis, Imaging and Interventional radiology from OPD. After obtaining clinical history relevant clinical examination was done.ASIA grading was done for neurological injury. MRI examinations were done. Every patient lay in supine position with quiet breathing. No movement was allowed during examination. In 71 percent of the patients, compression fracture of the vertebral body was present. Cord oedema of >3cm was seen in 55 percent of the patients. Sensory loss and motor loss was seen in 26 percent and 21 percent of the patients respectively. MRI findings in acute spinal cord injury correlate well with the initial clinical findings and can be helpful to clinician in predicting the outcome and extent of recovery in patients of spinal cord injury.

Diaphragm EMG activity during hyperbaric oxygen exposure in spinal injured rats

Cervical spinal cord injury can cause significant respiratory dysfunction and in severe cases necessitates mechanical ventilation. Accumulating evidence indicates that hyperbaric oxygen (HBO) therapy, initiated shortly after spinal cord injury (SCI), can mitigate spinal cord pathology. Further, a recent study from our group demonstrated that HBO therapy can attenuate diaphragm atrophy after SCI. The primary purpose of the present investigation was to evaluate diaphragm electromyogram (EMG) activity during HBO therapy in rats with cervical SCI. HBO therapy has not been widely adopted after SCI, and if HBO is to be translated to human use, we reasoned that it is important to determine how breathing is impacted during HBO exposure. Adult female Sprague‐Dawley rats were implanted with chronic indwelling EMG electrodes in the mid‐costal diaphragm two weeks prior to SCI. Following hemicontusion injury of the C4 spinal cord, one experimental group was treated with HBO (n=3), and another group was left untreated (n=3). The HBO treatment consisted of a one hour exposure to 100% O2 at 3 atmospheres (ATA). In all experiments, diaphragm EMG activity was recorded in freely moving rats, without anesthesia. Recordings were made for 10 minutes prior to treatment, throughout the HBO exposure, and for 10 minutes after. Diaphragm EMG recordings in the normobaric normoxia control group conditions were completed for the same duration of time as the treated group. Daily HBO treatment and EMG recordings were done until 10‐days post‐SCI. Peak diaphragm EMG burst amplitude was quantified before SCI, over the 10 days of treatment, and at 1 and 2 weeks post‐treatment. Prior to SCI, body weight was similar between groups (control: 227±4 g; HBO: 228±3 g). All rats with tolerated HBO treatment with no evidence of adverse events or impact on weight gain over the 10 day period (10 day body weight: control: 198 ± 14 g; HBO: 197 ± 13 g). The acute HBO exposure caused an increase in the area under the curve of the rectified and integrated inspiratory burst amplitude of the diaphragm recording made ipsilateral to the lesion. This increase averaged 126 ± 18% of baseline across the 10 HBO treatments. The ipsilateral EMG burst amplitude also remained elevated at 10 min post‐HBO exposure (115 ± 32%) compared to pre HBO exposure. At the conclusion of the 10 day treatment paradigm, ipsilateral diaphragm EMG output during quiet breathing was elevated in HBO (156 ± 50% of post‐injury baseline) as compared to the control group (111 ± 6% of baseline). However the ipsilateral diaphragm EMG burst amplitude of the two groups were similar when evaluated 2 weeks after the daily HBO sessions concluded. This ongoing study indicates that acute exposure to HBO therapy is associated with an increase in diaphragm EMG activity, and 10 days of HBO therapy accelerates the recovery of diaphragm activation following cervical contusion injury.

Confiabilidad interevaluador de la medición de la excursión diafragmática y fracción de engrosamiento diafragmático mediante ultrasonografía en voluntarios sanos

Background and objectiveTo determine the inter-rater reliability in the ultrasonographic (US) measurement of the diaphragmatic excursion (DE) and the diaphragm thickness fraction (DTF) performed by non-medical health professionals in healthy people. Participants and methodsProspective observational study in a third level hospital in Cali, Colombia. Measurements were made to 30 healthy volunteers chosen by convenience sampling, without a history of lung diseases, with ages between 18-60 years. A pilot test was previously carried out with 8 healthy volunteers. US measurements of DE, and DTF were based on previously published protocols. Each assessor independently observed several cycles of normal quiet breathing for 3minutes to establish a baseline. The Intraclass Correlation Index (ICC) was used to evaluate the inter-rater reliability in the measurements of DE and DTF, with 95% confidence intervals and a P<.05. ResultsSubstantial agreement was identified in the measurement of DE in the splenic and hepatic windows because the ICC was greater than 0.6 (P<.05). The measurement of the DTF in the hepatic window showed slight agreement in both 2D and M modes (P>.05). In the splenic window, the measurement of the DTF in the 2D mode was found to be moderate agreement and for the M mode a slight agreement was found (P>.05) ConclusionsThe diaphragmatic US constitutes a reproducible method with acceptable inter-rater reliability for the measurement of inspiratory/expiratory thickness, and with little reliability for the measurement of DTF.

Computer Modeling of D, L – Homocysteic Acid Microinjection into the Bötzinger Complex Area

Abstract The impact of D,L – homocysteic acid (DLH) microinjection (non-specific glutamate receptor agonist that causes excitation of neurons) into the Bötzinger complex area (BOT) was simulated using computer model of quiet breathing and cough reflex. Integrated signals from simulated neuronal populations innervating inspiratory phrenic and expiratory lumbar motoneurons were obtained. We analysed durations and amplitudes of these “pre-phrenic and pre-lumbar” activities during quiet breathing and cough reflex and the number of coughs elicited by a fictive 10-second-long stimulation. Model fibre population provides virtual DLH related excitation to expiratory neuronal populations with augmenting discharge pattern (BOT neurons). The excitation was modelled by a higher number of fibres and terminals (simulated a higher number of excitatory inputs) or by a higher synaptic strength (simulated a higher effect of excitatory inputs). Our simulations have demonstrated a high analogy of cough and breathing changes to those observed in animal experiments. The simulated neuronal excitations in the BOT led to cough depression represented by a lower cough number and a cough neuronal activity of the lumbar nerve. Despite the shortening of the phrenic activity during cough (compared to quiet breathing), which was not observed in animal experiments, our simulations confirm the ability of the computer model to simulate motor processes in the respiratory system. The computer model of functional respiratory / cough neural network is capable to confirm and / or predict the results obtained on animals.

Breathing pattern and muscle activity using different inspiratory resistance devices in children with mouth breathing syndrome.

AimThe aim of this study was to evaluate the acute effects of different inspiratory resistance devices and intensity of loads via nasal airway on the breathing pattern and activity of respiratory muscles in children with mouth breathing syndrome (MBS).MethodsChildren with MBS were randomised into two groups based on inspiratory load intensity (20% and 40% of the maximal inspiratory pressure). These subjects were assessed during quiet breathing, breathing against inspiratory load via nasal airway and recovery. The measurements were repeated using two different devices (pressure threshold and flow resistance). Chest wall volumes and respiratory muscle activity were evaluated by optoelectronic plethysmography and surface electromyography, respectively.ResultsDuring the application of inspiratory load, there was a significant reduction in respiratory rate (p<0.04) and an increase in inspiratory time (p<0.02), total time of respiratory cycle (p<0.02), minute ventilation (p<0.03), tidal volume (p<0.01) and scalene and sternocleidomastoid muscles activity (root mean square values, p<0.01) when compared to quiet spontaneous breathing and recovery, regardless of load level or device applied. The application of inspiratory load using the flow resistance device showed an increase in the tidal volume (p<0.02) and end-inspiratory volume (p<0.02).ConclusionFor both devices, the addition of inspiratory loads using a nasal interface had a positive effect on the breathing pattern. However, the flow resistance device was more effective in generating volume and, therefore, has advantages compared to pressure threshold.

Ventilation asymmetry, diaphragmatic mobility and exercise capacity in men with traumatic brachial plexus injury

ObjectiveTo investigate the repercussions of traumatic brachial plexus injury (TBPI) on diaphragmatic mobility and exercise capacity, compartmental volume changes, as well as volume contribution of each hemithorax and ventilation asymmetry during different respiratory maneuvers, and compare with healthy individuals. The velocity of shortening of the diaphragm, inspiratory, and expiratory muscles were also assessed. ParticipantsThe cross-sectional study was conducted with 40 male individuals (20 with TBPI who have not undergone nerve transfer surgery [mean age 30.1 ± 5.3] and 20 healthy paired by age and body mass index). Only patients with C8-T1 root avulsion were studied. Main outcomeCompartmental and hemithoracic volumes, as well as asymmetry between the affected and unaffected sides were assessed using optoelectronic plethysmography. The 6 minute walking test was performed to evaluate exercise capacity, while diaphragm mobility was assessed during quiet breathing (QB) using an ultrasound device. ResultsTBPI patients with mean lesion time of 174 ± 45.24 days showed a decreased pulmonary function, respiratory muscle strength, exercise capacity, and diaphragm mobility (all p < .001) compared with healthy. The pulmonary ribcage compartment of the affected side was the main contributor to the reduction in volume during inspiratory capacity, vital capacity, and inspiratory load imposition (all p < .05). This compartment also exhibited a higher ventilation asymmetry with reduced shortening velocity of the inspiratory ribcage muscles. ConclusionCompared with healthy, TBPI patients who have not undergone nerve transfer surgery present low exercise capacity and diaphragmatic mobility, as well as reduced volume of the upper ribcage compartment on the affected side that leads to reduced shortening velocity and ventilation asymmetry.

The Amplitude of Diaphragm Compound Muscle Action Potential Correlates With Diaphragmatic Excursion on Ultrasound and Pulmonary Function After Supraclavicular Brachial Plexus Block.

ObjectiveThis prospective, double-blind, randomized study assessed (1) the associations between diaphragm compound muscle action potential (CMAP), hemidiaphragmatic excursion, and pulmonary function after supraclavicular brachial plexus block (SCBPB) and (2) diagnostic efficacy of pulmonary function for hemidiaphragmatic paralysis evidenced by diaphragm CMAP as an assessment of diaphragm strength was evaluated.MethodsEighty-six patients were scheduled for the removal of hardware after healing of a right upper limb fracture distal to the shoulder who were randomly assigned in a 1:1 ratio to two groups: Group A (diaphragmatic excursion), or Group B (pulmonary function). Phrenic nerve conduction studies (PNCSs), M-mode ultrasonography of the diaphragm, and pulmonary function tests (PFTs) were performed before and 30 min after SCBPB. PNCSs were used to determine the latency and amplitude of diaphragm CMAP. Ultrasonography of the diaphragm was performed with patients in a supine position using a low-frequency probe over the subcostal space at the midclavicular line. The diaphragmatic excursion was measured during quiet breathing and deep breathing. Pulmonary function, i.e., forced vital capacity (FVC), predicted value of FVC, and forced expiratory flow in the first second (FEV1), was measured with spirometry. Receiver Operating Characteristic (ROC) curve analysis was used to assess the diagnostic efficacy of pulmonary function for hemidiaphragmatic paralysis evidenced by diaphragm CMAP as an assessment of diaphragm strength.ResultsThere were significant associations between the reduction in amplitude of diaphragm CMAP and reductions in diaphragmatic excursion during quiet breathing (r = 0.70, p < 0.01) and deep breathing (r = 0.63, p < 0.01) when expressed as a percentage of baseline values. There were significant associations between the reduction in amplitude of diaphragm CMAP and reductions in FVC (r = 0.67, p < 0.01), FVC% (r = 0.67, p < 0.01), and FEV1 (r = 0.62, p < 0.01), when expressed as percentage of baseline values. The area under the ROC curve for FVC was 0.86. A decrease of >8.4% in FVC compared to pre-block predicted hemidiaphragmatic paralysis (determined by diaphragm CMAP) with sensitivity and specificity of 79.2 and 100%, respectively.ConclusionsThe relative reduction in diaphragm CMAP amplitude after SCBPB was correlated with relative reductions in diaphragmatic excursion and pulmonary function. FVC has potential as a useful diagnostic indicator of hemidiaphragmatic paralysis, evidenced by diaphragm CMAP, after SCBPB. These data establish diaphragm CMAP as a direct and objective index of diaphragmatic paralysis after SCBPB.

Intrarater Reliability of Diaphragm Excursion and Resting Thickness Using Ultrasound Imaging in Subjects With Nonspecific Chronic Low Back Pain

ObjectiveThe purpose of this study was to establish within-day intrarater reliability values of ultrasound measurements (excursion and resting thickness). MethodsSeventeen volunteers met the inclusion criteria for this preliminary study. The right and left hemidiaphragm excursion and resting thickness were compared between 2 measurement sessions using M-mode and B-mode real-time ultrasound, respectively (30 min apart). Intraclass coefficients, coefficients of variation, standard errors of measurement, and minimal detectable changes were calculated to determine intrarater reliability. ResultsThe intraclass coefficients of right hemidiaphragm excursion were 0.91 and 0.94 during quiet and deep breathing, respectively. The intraclass coefficient of left hemidiaphragm excursion was 0.95 during quiet breathing. The intraclass coefficients of diaphragm resting thickness were 0.99 and 0.97 in the right and left hemidiaphragm, respectively, which showed high intrarater reliability for ultrasound measurements of both sides of the diaphragm. ConclusionThis preliminary study suggests that diagnostic ultrasonography could be used as a potential method for measuring the resting thickness and excursion of the right and left hemidiaphragm in people with chronic low back pain. Future research with a larger sample size is needed to confirm these findings.

Is Free Breathing Possible During Computed Tomography-Guided Percutaneous Transthoracic Lung Biopsy? The Clinical Experience in 585 Cases.

The aim of the study was to retrospectively evaluate the safety and accuracy of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions during quiet breathing. We investigated the diagnostic performance and complication rate of 585 procedures in 563 patients (357 men; mean age, 67.7 years), who underwent CT-guided PTNBs during quiet breathing, aided by a respiratory targeting technique from May 2017 to July 2019. Differences between the cases with and without respiratory targeting were analyzed. Logistic regression analyses were performed to examine the development of pneumothorax and hemoptysis. Percutaneous transthoracic needle biopsy samples were successfully obtained in 574 of 585 procedures (98.1%). Final diagnoses included: 410 malignant cases, 119 benign cases, and 45 indeterminate cases. The sensitivity, specificity, and accuracy of diagnosis were 94.4%, 100%, and 95.7%, respectively. Use of respiratory targeting was associated with younger age (P = 0.004), smaller lesion size (P < 0.001), peripheral location (P = 0.003), shorter distance from the diaphragm (P < 0.001), lower lobe location (P < 0.001), prone position (P = 0.004), and visible motion artifact (P < 0.001). Pneumothorax and hemoptysis rates were 22.9% and 7.9%, respectively. Upon multivariate analysis, emphysema (P = 0.002) was the only independent risk factor for pneumothorax, whereas distance from the pleura greater than 2 cm (P < 0.001), tissue sampling 3 times or more (P = 0.003), and a less experienced operator (P < 0.001) were risk factors for hemoptysis. Computed tomography-guided PTNB during quiet breathing with respiratory targeting yielded high diagnostic performance with a slightly higher rate of complications. Free-breathing PTNB can be applied in clinical practice, based on lesion location and risk factors for complications.

Detection of Aortic Valve Opening and Estimation of Pre-Ejection Period in Forcecardiography Recordings.

Forcecardiography (FCG) is a novel technique that measures the local forces induced on the chest wall by the mechanical activity of the heart. Specific piezoresistive or piezoelectric force sensors are placed on subjects’ thorax to measure these very small forces. The FCG signal can be divided into three components: low-frequency FCG, high-frequency FCG (HF-FCG) and heart sound FCG. HF-FCG has been shown to share a high similarity with the Seismocardiogram (SCG), which is commonly acquired via small accelerometers and is mainly used to locate specific fiducial markers corresponding to essential events of the cardiac cycle (e.g., heart valves opening and closure, peaks of blood flow). However, HF-FCG has not yet been demonstrated to provide the timings of these markers with reasonable accuracy. This study addresses the detection of the aortic valve opening (AO) marker in FCG signals. To this aim, simultaneous recordings from FCG and SCG sensors were acquired, together with Electrocardiogram (ECG) recordings, from a few healthy subjects at rest, both during quiet breathing and apnea. The AO markers were located in both SCG and FCG signals to obtain pre-ejection periods (PEP) estimates, which were compared via statistical analyses. The PEPs estimated from FCG and SCG showed a strong linear relationship (r > 0.95) with a practically unit slope, and 95% of their differences were found to be distributed within ± 4.6 ms around small biases of approximately 1 ms, corresponding to percentage differences lower than 5% of the mean measured PEP. These preliminary results suggest that FCG can provide accurate AO timings and PEP estimates.

Comparing the Effects of Short-Term Liuzijue Exercise and Core Stability Training on Balance Function in Patients Recovering From Stroke: A Pilot Randomized Controlled Trial.

AimsLiuzijue Qigong (LQG) exercise is a traditional Chinese exercise method in which breathing and pronunciation are combined with movement guidance. Breathing is closely related to balance, and LQG, as a special breathing exercise, can be applied to balance dysfunction after stroke. The purpose of this study was to observe the clinical effects of short-term LQG exercise on balance function in patients recovering from stroke.MethodsStroke patients were randomly divided into an Intervention Group (IG) (n = 80) and a Control Group (CG) (n = 80). The IG received conventional rehabilitation training plus LQG and the CG received conventional rehabilitation training plus Core Stability Training (CST). All patients received treatment once a day, 5 times a week for 2 weeks. The primary outcome was Berg Balance Scale (BBS). Secondary outcome measures were static standing and sitting balance with eyes open and closed, Fugl-Meyer Assessment (FMA), Maximum Phonation Time (MPT), Modified Barthel Index (MBI) and diaphragm thickness and mobility during quiet breath (QB) and deep breath (DB).ResultsCompared with the CG, the IG showed significant improvement in the BBS (10.55 ± 3.78 vs. 9.06 ± 4.50, P = 0.039), MPT (5.41 ± 4.70 vs. 5.89 ± 5.24, P = 0.001), MBI (12.88 ± 6.45 vs. 10.00 ± 4.84, P = 0.003), diaphragmatic mobility during QB (0.54 ± 0.73 vs. 0.33 ± 0.40, P = 0.01) and diaphragmatic mobility during DB (0.99 ± 1.32 vs. 0.52 ± 0.77, P = 0.003), Cop trajectory in the standing position with eyes open (−108.34 ± 108.60 vs. −89.00 ± 140.11, P = 0.034) and Cop area in the standing positions with eyes open (−143.79 ± 431.55 vs. −93.29 ± 223.15, P = 0.015), Cop trajectory in the seating position with eyes open (−19.95 ± 23.35 vs. −12.83 ± 26.64, P = 0.001) and Cop area in the seating position with eyes open (−15.83 ± 9.61 vs. −11.29 ± 9.17, P = 0.002).ConclusionsThe short-term LQG combined with conventional rehabilitation training significantly improved the balance functions of stroke patients. It also improved static standing and sitting balance with the eyes open, diaphragm functions, maximum phonation time and the quality of daily life for stroke patients.Clinical Trial Registrationhttp://www.chictr.org.cn/edit.aspx?pid=25313&htm=4, Identifier: ChiCTR1800014864.

Breathing patterns recognition: A functional data analysis approach

Background and ObjectiveThe ongoing pandemic proved fundamental is to assess a subject's respiratory functionality and breathing pattern measurement during quiet breathing is feasible in almost all patients, even those uncooperative. Breathing pattern consists of tidal volume and respiratory rate in an individual assessed by data tracks of lung or chest wall volume over time. State-of-art analysis of these data requires operator-dependent choices such as individuation of local minima in the track, elimination of anomalous breaths and individuation of breath clusters corresponding to different breathing patterns. MethodsA semi-automatic, robust and reproducible procedure was proposed to pre-process and analyse respiratory tracks, based on Functional Data Analysis (FDA) techniques, to identify representative breath curve and the corresponding breathing patterns. This was achieved through three steps: 1) breath separation through precise localization of the minima of the volume trace; 2) functional outlier breaths detection according to time-duration, magnitude and shape; 3) breath clustering to identify different pattern of interest, through K-medoids with Alignment. The method was firstly validated on simulated tracks and then applied to real data in conditions of clinical interest: operational volume change, exercise, mechanical ventilation, paradoxical breathing and age. ResultsThe total error in the accuracy of minima detection and in was less than 5%; with the artificial outliers being almost completely removed with an accuracy of 99%. During incremental exercise and independently on the bike resistance level, five clusters were identified (quiet breathing; recovery phase; onset of exercise; maximal and intermediate levels of exercise). During mechanical ventilation, the procedure was able to separate the non-ventilated from the ventilatory-supported breathing and to identify the worsening of paradoxical breathing due to the disease progression and the breathing pattern changes in healthy subjects due to age. ConclusionsWe proposed a robust validated automatic breathing patterns identification algorithm that extracted representative curves that could be implemented in clinical practice for objective comparison of the breathing patterns within and between subjects. In all case studies the identified patterns proved to be coherent with the clinical conditions and the physiopathology of the subjects, therefore enforcing the potential clinical translational value of the method.

In Vitro Evaluation of a Nasal Interface Used to Improve Delivery From a Portable Oxygen Concentrator

Abstract Portable oxygen concentrators (POCs) are widely used to administer long-term oxygen therapy (LTOT) and employ pulsed delivery modes to conserve oxygen. Efficient pulsed delivery requires that POCs are triggered by patient inhalation. Triggering is known to fail for some patients during periods of quiet breathing, as occurs during sleep. This article describes a new nasal interface designed to improve triggering of pulsed oxygen delivery from POCs. In vitro experiments incorporating realistic nasal airway replicas and simulated breathing were conducted. The pressure monitored via oxygen supply tubing (the signal pressure) was measured over a range of constant inhalation flow rates with the nasal interface inserted into the nares of the nasal airway replicas, and then compared with signal pressures measured for standard and flared nasal cannulas. The triggering efficiency and fraction of inhaled oxygen (FiO2) were next evaluated for the nasal interface and cannulas used with a commercial POC during simulated tidal breathing through the replicas. Higher signal pressures were achieved for the nasal interface than for nasal cannulas at all flow rates studied. The nasal interface triggered pulsed delivery from the POC in cases where nasal cannulas had failed to do so. FiO2 was significantly higher for successful triggering cases than for failed triggering cases. The nasal interface improved triggering of pulsed oxygen delivery from a POC and presents a simple solution that could be used with commercially available POCs to reliably supply oxygen during periods of quiet breathing.

Effect of pursed-lip breathing and forward trunk lean positions on regional chest wall volume and ventilatory pattern in older adults: An observational study.

Pursed-lip breathing (PLB) and forward trunk lean posture (FTLP) are commonly used to relieve dyspnea and improve ventilation in a rehabilitation program. However, their effect on chest wall volumes and movements in older adults without chronic obstructive pulmonary disease has never been investigated. This observational study aimed to identify the effect of combined PLB and FTLP on total and regional chest wall volumes, ventilatory pattern, and thoracoabdominal movement using in older adults. It was hypothesized that the combined PLB with FTLP would result in the highest chest wall volumes among the experimental tasks. Twenty older adults performed 2 breathing patterns of quiet breathing (QB) and PLB during a seated upright (UP) position and FTLP. An optoelectronic plethysmography system was used to capture the chest wall movements during the 4 experimental tasks. Tidal volume (VT) was separated into pulmonary ribcage, abdominal ribcage, and abdomen volume. The changes in anterior–posterior (AP) and medial–lateral (ML) chest wall diameters at 3 levels were measured and used to identify chest wall mechanics to improve chest wall volumes. The PLB significantly improved ventilation and chest wall volumes than the QB (P < .05). VT of pulmonary ribcage, VT of abdominal ribcage, and VT were significantly higher during the PLB + UP (P < .05) and during the PLB + FTLP (P < .01) as compared to those of QB performed in similar body positions. However, there was no significant in total and regional lung volumes between the PLB + UP and the PLB + FTLP. The AP diameter changes at the angle of Louis and xiphoid levels were greater during the PLB + UP than the QB + UP and the QB + FTLP (P < .01). The AP diameter changes at the umbilical level and the ML diameter changes at the xiphoid level were significantly larger during the PLB + FTLP than the QB + FTLP and the QB + UP (P < .05). The ML diameter changes at the umbilical level were significantly greater during the PLB + FTLP than the QB + UP (P < .05). However, no significant difference in the relative regional chest wall volumes and phase angle among the experimental tasks (P > .05). In conclusion, a combined PLB performed in an FTLP or UP sitting could be used as a strategy to improve chest wall volumes and ventilation in older adults.

Median arcuate ligament syndrome with predominantly respiratory manifestatios

Introduction. One of the causes of respiratory disorders in young people may be visceral circulation chronic vio-lation in median arcuate ligament syndrome (MALS). The aim of the study was to assess the clinical significance of respiratory disorders in establishing the MALS diagnosis in order to determine the necessary management tactics for patients with this pathology. Materials and methods.49 MALS patients were examined, the main symptoms being respiratory disorders, such as shortness of breath, difficult inhaling and/or exhaling, and others. The medi-an age was 24.7±0.9 years, females predominated (60%). The diagnosis of MALS was confirmed by clinical data, the results of transabdominal ultrasound duplex scanning of the abdominal aorta and its visceral branches using re-spiratory and orthostatic tests. Subsequent comparative analysis of the characteristic respiratory symptoms’ seve-rity before and after surgery (decompression of the celiac trunk) was performed. Research results. 10 main symp-toms of respiratory disorders were identified in patients under study, the frequency of each ranged from 31% to 50%, in most patients they were combined. Spirometry in these patients did not reveal any changes in both static lung volumes or airway patency. Bronchodilation revers-ibility tests were negative. Chest X-ray and/or computed tomography did not reveal any visible changes. During examination, hemodynamically significant compres-sion stenosis of the celiac trunk (CT) was observed in all patients. For all patients, auscultation of the abdominal cavity and detection of systolic murmur were performed. Confirmation of the diagnosis was based on ultrasound of the unpaired visceral arteries with color mapping, im-aging of the severity of CT stenosis, nature and speed of blood flow. An ultrasound study of the diaphragm func-tion revealed a direct statistically significant relationship between the diameter of the orifice of the CT and the am-plitude of the respiratory displacement of the diaphragm dome during quiet breathing (r=0.58), the amplitude of the respiratory displacement of the diaphragm dome during forced breathing (r=0.64), and the thickening frac-tion of the muscular part of the diaphragm, with quiet breathing (r=0.61) and thickening fraction of the muscu-lar part of the diaphragm during forced breathing (r=0.46, not significant, trend). The given correlation coefficients were estimated as a medium-strength relationship, i.e., the narrower the CT mouth, the worse the diaphragm ki-netics. In most patients, after surgical treatment, decom-pression of the celiac trunk, the clinical manifestations of respiratory disorders resolved, which may indicate their connection with diaphragmatic compression stenosis of the CT. Conclusion. The clinical manifestations of respi-ratory disorders in MALS, in most cases, are similar to the symptoms of bronchial asthma, which often led to the establishment of an erroneous diagnosis and ineffective-ness of the prescribed therapy. This theoretically and clin-ically important circumstance must be taken into account in the differential diagnosis of celiac trunk compression syndrome in combination with respiratory disorders. In the presence of hemodynamically significant compres-sion stenosis of the CT and respiratory disorders, it is ad-visable to perform surgical intervention

Evaluation of Correlation Between Surface Diaphragm Electromyography and Airflow Using Fixed Sample Entropy in Healthy Subjects.

In clinic, the acquisition of airflow with nasal prongs, masks, thermistor to monitor respiratory function is more uncomfortable and inconvenience than surface diaphragm electromyography (EMGdi) using electrode pads. The EMGdi with strong electrocardiograph (ECG) interference affect the extraction of its characteristic information. In this work, surface EMGdi and airflow signals of 20 subjects were collected under 5 incremental inspiratory threshold loading protocols from quiet breathing to maximum forced breathing. First, we filtered out the ECG interference in EMGdi based on the combination of stationary wavelet transform and the positioning of ECG to obtain pure EMGdi (EMGdip). Second, the Spearman's rank correlation coefficients between EMGdi and EMGdip quantified by time series fixed sample entropy (fSampEn), root mean square (RMS), and envelope were compared to verify the robustness of the fSampEn to ECG. A comparative analysis of correlation between fSampEn of EMGdi and inspiratory airflow and the correlation between envelope of EMGdip (EMGdie) and inspiratory airflow found that there was no significant difference between the two, indicating the feasibility of using fSampEn to predict airflow. Moreover, fSampEn of EMGdi was used as characteristic parameter to build a quantitative relationship with the airflow by polynomial regression analysis. Mean coefficient of determination of all subjects in any breathing state is greater than 0.88. Finally, nonlinear programming method was used to solve a universal fitting coefficient between fSampEn of EMGdi and airflow for each subject to further evaluate the possibility of using surface EMGdi to monitor and control respiratory activity.

The Role of the Diaphragm in Postural Stability and Visceral Function in Parkinson's Disease.

Background: In normal subjects, the diaphragm plays a key functional role in postural stability, articulation, respiration, defecation, and urination.Objectives: The aim of this study was to investigate the role of the diaphragm in postural stability and visceral function in patients with Parkinson’s disease (PD) and to compare the diaphragm function by gender, Hoehn and Yahr (H&Y) staging, and motor subtypes.Methods: In total, 79 patients were enrolled in this cross-sectional study. The severity of the disease was assessed by the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale III and by H&Y staging. Postural stability was quantitatively recorded, and respiratory function was evaluated by spirometry. Several scales were used to evaluate visceral function in patients with PD. In addition, diaphragm ultrasound was used to measure the excursion, contraction velocity, and thickness of the diaphragm during quiet breathing, deep breathing, and the sniff test. Significant features were selected by the least absolute shrinkage and selection operator (LASSO) regression and fitted in the multivariate linear regression and Pearson’s correlation analysis.Results: Diaphragm thickness and excursion during quiet breathing were significantly different between men and women and between H&Y stage 1–2 and stage 2.5–3, whereas the diaphragm function was not influenced by motor subtypes. It was shown that the diaphragmatic function was significantly correlated with postural stability, voice function, respiratory function, constipation, and urological function to varying degrees in patients with PD.Conclusion: The diaphragmatic function is associated with dysfunction in PD although it remains unclear as to whether the observed changes in the diaphragm are primary or secondary.