Breathing Maneuvers Research Articles

Indices of acceleration atelectasis and the effect of hypergravity duration on its development.

What is the central question of the study? The aim was to determine the effects of duration of acceleration in the cranial-caudal direction (+Gz) on acceleration atelectasis and identify measurement techniques that can be used to assess it. What is the main finding and its importance? Non-invasive measurement of acceleration atelectasis using electrical impedance tomography and estimates of pulmonary shunt provide more detailed assessment of acceleration atelectasis than traditional forced vital capacity measures. Using these techniques, it was found that as little as 30s of exposure to +Gz acceleration can cause acceleration atelectasis. The results of the present study will allow a more accurate and detailed assessment of acceleration atelectasis in the future. Recently, there have been reports of acceleration atelectasis during fast jet flight despite the use of systems designed to minimize this. Before further investigation of this, indices suitable for use in applied settings and identification of acceleration durations that elicit it are required. Fifteen non-aircrew subjects underwented five centrifuge exposures lasting 15, 30, 60 and 2×90s with a plateau of +5 Gz (acceleration in the cranial-caudal direction) while breathing 94% O2 during all but one control exposure (21% O2 ). Lung volumes and gas exchange limitation were assessed after each exposure. Regional lung impedance and compliance were measured after Gz exposure using electrical impedance tomography and the forced oscillatory technique, respectively. The presence of acceleration atelectasis was confirmed by reductions of 10-17% in vital and inspiratory capacity after 60 and 90s Gz exposures (P<0.05) and resulted in reduced regional lung impedance and a gas exchange limitation of 8.1 and 12.5%, respectively (P<0.05). There was also a small but significant decrease in regional lung impedance after 30s exposures. Functional residual capacity and lung compliance were unchanged in atelectatic lungs (P>0.05). In the majority of individuals,>60 s of Gz exposure while breathing 94% O2 causes acceleration atelectasis. Electrical impedance tomography and the measurement of gas exchange limitation provide useful indicators of acceleration atelectasis. Acceleration atelectasis exerts its effects primarily through basal lung closure and reflex inspiratory limitation, both of which can be reversed by performing three maximal inspiratory breathing manoeuvres.

Evaluation of Respiratory Muscle Strength and Diaphragm Ultrasound: Normative Values, Theoretical Considerations, and Practical Recommendations

Background: Reference values derived from existing diaphragm ultrasound protocols are inconsistent, and the association between sonographic measures of diaphragm function and volitional tests of respiratory muscle strength is still ambiguous. Objective: To propose a standardized and comprehensive protocol for diaphragm ultrasound in order to determine lower limits of normal (LLN) for both diaphragm excursion and thickness in healthy subjects and to explore the association between volitional tests of respiratory muscle strength and diaphragm ultrasound parameters. Methods: Seventy healthy adult subjects (25 men, 45 women; age 34 ± 13 years) underwent spirometric lung function testing, determination of maximal inspiratory and expiratory pressure along with ultrasound evaluation of diaphragm excursion and thickness during tidal breathing, deep breathing, and maximum voluntary sniff. Excursion data were collected for amplitude and velocity of diaphragm displacement. Diaphragm thickness was measured in the zone of apposition at total lung capacity (TLC) and functional residual capacity (FRC). All participants underwent invasive measurement of transdiaphragmatic pressure (Pdi) during different voluntary breathing maneuvers. Results: Ultrasound data were successfully obtained in all participants (procedure duration 12 ± 3 min). LLNs (defined as the 5th percentile) for diaphragm excursion were as follows: (a) during tidal breathing: 1.2 cm (males; M) and 1.2 cm (females; F) for amplitude, and 0.8 cm/s (M) and 0.8 cm/s (F) for velocity, (b) during maximum voluntary sniff: 2.0 cm (M) and 1.5 cm (F) for amplitude, and 6.7 (M) cm/s and 5.2 cm/s (F) for velocity, and (c) at TLC: 7.9 cm (M) and 6.4 cm (F) for amplitude. LLN for diaphragm thickness was 0.17 cm (M) and 0.15 cm (F) at FRC, and 0.46 cm (M) and 0.35 cm (F) at TLC. Values for males were consistently higher than for females, independent of age. LLN for diaphragmatic thickening ratio was 2.2 with no difference between genders. LLN for invasively measured Pdi during different breathing maneuvers are presented. Voluntary Pdi showed only weak correlation with both diaphragm excursion velocity and amplitude during forced inspiration. Conclusions: Diaphragm ultrasound is an easy-to-perform and reproducible diagnostic tool for noninvasive assessment of diaphragm excursion and thickness. It supplements but does not replace respiratory muscle strength testing.

Assessing paediatric exercise-induced bronchoconstriction using electromyography.

BackgroundAsthma is one of the most common chronic diseases in childhood, occurring in up to 10% of all children. Exercise-induced bronchoconstriction (EIB) is indicative of uncontrolled asthma and can be assessed using an exercise challenge test (ECT). However, this test requires children to undergo demanding repetitive forced breathing manoeuvres. We aimed to study the electrical activity of the diaphragm using surface electromyography (EMG) as an alternative measure to assess EIB.MethodsForty-two children suspected of EIB performed an ECT wearing a portable EMG amplifier. EIB was defined as a fall in FEV1 of more than 13%. Children performed spirometry before exercise, and at 1, 3 and 6 min after exercise until the nadir FEV1 was attained and after the use of a bronchodilator. EMG measurements were obtained between spirometry measurements.ResultsTwenty out of 42 children were diagnosed with EIB. EMG peak amplitudes measured at the diaphragm increased significantly more in children with EIB; 4.85 μV (1.82–7.84), compared to children without EIB; 0.20 μV (−0.10–0.54), (p<0.001) at the lowest FEV1 post-exercise. Furthermore, the increase in EMG peak amplitude could accurately distinguish between EIB and non-EIB using a cut-off of 1.15 μV (sensitivity 95%, specificity 91%).ConclusionEMG measurements of the diaphragm are strongly related to the FEV1 and can accurately identify EIB. EMG measurements are a less invasive, effort-independent measure to assess EIB and could be an alternative when spirometry is not feasible.

Elevation of intracranial pressure affects the relationship between hemoglobin concentration and neuronal activation in human somatosensory cortex.

During neuronal activation, a local decrease of deoxygenated hemoglobin concentration (deoxy‐Hb) occurs which is the basis of functional brain imaging with blood oxygenation level dependent functional magnetic resonance imaging (BOLD‐fMRI). Elevated intracranial pressure (eICP) has been shown to impair functional deoxy‐Hb changes. This study investigated this effect and its relation to the underlying neuronal activity in the human primary somatosensory cortex (SI). Functional near‐infrared spectroscopy (fNIRS) during somatosensory evoked potentials (SEP) monitoring was performed on 75 subjects during conditions of median nerve stimulation (MNS) and resting state, combined with normal breathing (NB) and eICP by escalating breathing maneuvers (breath holding [BH], Valsalva maneuver with 15 mmHg [V15] and 35 mmHg expiratory pressure [V35]). During NB, fNIRS revealed a typical oxygenated hemoglobin concentration (oxy‐Hb) increase with deoxy‐Hb decrease during MNS enabling SI brain mapping. Breathing maneuvers associated eICP produced a known global change of oxy‐Hb and deoxy‐Hb with and without MNS. When subtracting measurements during resting state from measurements during MNS, neither functional oxy‐Hb nor deoxy‐Hb changes could be recovered while SEPs remained unchanged. In conclusion, Valsalva‐induced eICP prevents oxy‐Hb and deoxy‐Hb changes during neuronal activation in SI. This finding raises questions on the validity of oxy‐Hb‐ and deoxy‐Hb‐based brain imaging (e.g., BOLD‐fMRI) during eICP.

Towards whole-lung simulations of aerosol deposition: A model of the deep lung

In silico methods can be used to estimate regional deposition of inhaled aerosols in regions of the lung that are inaccessible by direct measurements. Knowledge of deposited dose is important for assessing the efficacy of inhaled pharmaceutical aerosols or the impact from exposure to environmental pollutants. Although patient-specific geometries of the upper airways are widely used nowadays, insufficient imaging resolution precludes the reconstruction of 3D models of the deeper lung generations. In the present study, the 3D model of the deep lung (DLM) we have previously developed is utilised to examine the effects of breathing profile, breathhold and gravity orientation on deposition in the deep airways. The objective is to assess whether a small number of DLMs could be utilised to provide deposition predictions in the entire peripheral lung, with the ultimate goal being the integration of DLM with imaging-derived models of the upper airways for whole-lung deposition predictions. It is found that deposition in the respiratory region during deep breathing increases remarkably compared to quiet breathing since particles avoid retention in the conducting generations. Significant increases in deposition are recorded when breathhold is employed, with approximately 70% rise in total deposition of 1–2 μm particles. Our findings indicate that the breathing maneuver can be used to target different deposition sites in the deep lung: deep inhalation followed by breathhold should be employed to achieve higher deposition in the respiratory region, whereas quiet inhalation followed by breathhold is recommended when targeting the deep conducting airways. Small differences in deposition during quiet inhalation are observed when the DLM is placed in seven different orientations relative to gravity. These differences are further reduced when realistic angle distributions are utilised for each of the five lung lobes and angle-weighted deposition fractions are compared. Our findings suggest that a small number of DLMs along with the distribution of gravity angles of an upper airway model could be employed to provide deposition estimates in the deep lung.

Effect of Left and Right Nostril Breathing on Heart Rate Variability among Healthy Adult Males: A Cross-sectional Study

The effects of various breathing manoeuvres on autonomic functions, especially those of alternate nostrilbreathing and single nostril breathing have been well documented.1,2,3,4 However, most of the studies haveinvestigated these effects after practiced breathing manoeuvres,5,6,7 and few have looked into the immediateeffects of such types of breathing. The purpose of this study was to determine the immediate effects of asingle session of single nostril breathing, first right nostril and then left nostril, on the various time andfrequency domain parameters of heart rate variability (HRV) and to compare these effects with that of HRVduring normal breathing.Sixty male volunteers (age range, 20 to 40 years) were assessed. Electrocardiography was conducted, usingstandard procedure, under controlled laboratory conditions, for three five-minute periods: during breathingnormally through both nostrils, during the last five minutes of a twenty-minute session of breathing throughthe right nostril only and similarly while breathing through the left nostril only. The R-R intervals obtainedwere analyzed for HRV parameters and further analyzed using different statistical method.When compared to right nostril breathing, a statistically significant increase in mean R-R intervals was notedwith left nostril breathing (p = 0.009). Sympathetic activation with right nostril breathing was also evident,although statistically not found to be significant. A statistically significant higher SDNN with left nostrilbreathing as compared to both nostril breathing (p = 0.004) was also observed. Similarly, NN50 and pNN50were found to be significantly higher with left nostril breathing as compared to both nostril breathing (p =0.003 &amp; 0.007, respectively). However, RMSSD, LF power, HF power, LF norm, HF norm and LF/HF ratiowere not found to be statistically different for the three breathing manoeuvres.Thus our study showed an overall parasympathetic predominance, with an increase in total power of HRVwith left nostril breathing, but the minute variations of HRV were not found to be significantly differentamong the three breathing manoeuvres.

Improving Contrast Enhancement in Pulmonary CTA: The value of breathing maneuvers

PurposeTo investigate contrast dynamics and artifacts associated with different breathing maneuvers during pulmonary computed tomography angiography (pCTA) in a prospective randomized clinical trial. MethodThree different breathing maneuvers (inspiration, expiration, Mueller) were randomly assigned to 146 patients receiving pCTA for suspected pulmonary embolism (PE). Contrast enhancement of central and peripheral arteries and imaging quality of lung parenchyma were compared and analyzed. Results were compared by using the analysis of variances (ANOVA) and Kruskal-Wallis-Test. ResultsMean enhancement in the pulmonary trunk was highest during breath-hold in inspiration (293 HU, range 195–460 HU) compared to Mueller (259 HU, range 136–429 HU, p = 0022) and expiration (267 HU, range 115–376 HU). This was similar for the right pulmonary artery (inspiration 289 HU, range 173–454 HU; Mueller 250 HU, range 119–378 HU; p = 0.007; expiration 257 HU, range 114–366 HU; p = 0.032) and left pulmonary artery (inspiration 280.3 HU, range 170–462 HU; Mueller 245 HU, range 111–371 HU; p = 0.016; expiration 252 HU, range 110–371 HU).Delineation of peripheral arteries was significantly better in inspiration vs Mueller (p = 0.006) and expiration (p = 0.049). Assessment of the lung parenchyma was significantly better in inspiration vs Mueller (p = 0.013) or expiration (p < 0.001). ConclusionsResting inspiratory position achieved the highest enhancement levels in central and peripheral pulmonary arteries and best image quality of the pulmonary parenchyma in comparison to other breathing maneuvers. It is necessary to train the maneuver prior to the examination in order to avoid deep inspiration with the risk of suboptimal opacification of the pulmonary arteries.

Diaphragm ultrasonography in adults with sickle cell anemia: evaluation of morphological and functional aspects

ABSTRACT Objectives To assess morphological and functional aspects of the diaphragm by ultrasonography (US) in adults with sickle cell anemia (SCA) and evaluate if the diaphragmatic musculature can play a role in changes found in pulmonary function tests (PFTs) of these patients. Methods This is a cross-sectional observational and single-center study involving 40 adults with SCA who underwent diaphragm US and PFTs with a maximum of 1 month between the two tests. Diaphragm US was performed in B and M modes, and echogenicity, thickness and movement of the muscle was assessed in different respiratory maneuvers. Results Diaphragms had preserved echogenicity and the thickness was not significantly different between the groups. The SCA group exhibited significantly higher movement of the right hemidiaphragm during deep breathing (p = 0.004) and the sniff test (p = 0.0008) and lower movement of the left hemidiaphragm during quiet breathing (p = 0.009). There was a predominance of restrictive pattern (65%) and a global reduction in respiratory muscle strength (RMS) (70%). Conclusions This study shows that adults with SCA had normal morphostructural aspects and absence of diaphragm dysfunction. Otherwise, they presented greater movement of the right hemidiaphragm during deep breathing and sniff test maneuvers. Despite the restrictive pattern and the reduction in RMS found in PFTs, the diaphragm of young adults with SCA did not have weakness or paralysis.

66 Simple bedside cardiovascular autonomic examinations for predicting chronotropic incompetence

Abstract Background Simple bedside cardiovascular autonomic reflex test (CARTs) are usually used to determine cardiovascular autonomic neuropathy (CAN). CAN may contribute to chronotropic incompetence (CI) which is the inability of the heart rate (HR) to rise in proportion to an increase in metabolic demand. Determination of CI is widely based on measurement of maximum HR during exercise testing. This study aimed to evaluate the role of CARTs to determine CI. Methods We included in 105 patients using a derivation and validation sampling ratio of 2:1. CARTs were performed for analyzing heart rate variation during three parasymphathetic standard tests (deep breathing, lying to standing, Valsava maneuver) and two sympathetic standard tests (systolic blood pressure from lying to standing and diastolic blood pressure during handgrip maneuver). Variables independently associated with CI in multivariable analysis in the derivation set were assigned points based on their respective odds ratios. Results CI group showed significantly lower values of among three parasympathetic standard tests (p &amp;lt; 0.05) but not significantly among two sympathetic standars tests. Valsava maneuver (OR 0.1, p &amp;lt; 0.001, 95%CI 0.001-0.004), deep breathing (OR 0.91, p = 0.025, 95% CI 0.836-0.988), and handgrip maneuver (OR 0.85, p = 0.01, 95% CI 0.744-0.961) were found to be an independent risk factor for CI from multivariate regression analysis. The accuracy of different CART parameters in the prediction of CI was described by the receiver operating curve (ROC) analysis. Regarding logistic regression model, we constructed formula of 15 - ([12 x Valsava maneuver] + [0.1 x deep breathing] + [0.2 x handgrip maneuver]) which will show negative and positive results indicating CI and non-CI, respectively. The resulting score showed good calibration and discriminatory capacity in the derivation (Hosmer-Lemeshow x² 10.051, p = 0.186, AUC = 0.878). The difference between AUCs in the derivation and validation sets was Δ = 0.122 (p = 0.174). Conclusion The decrease in heart rate variations during Valsava maneuver and deep breathing and in diastolic blood pressure during handgrip maneuver seems to be related to development of CI. Formula of CARTs score is a useful tool for predicting CI. Final score sheet based on formula Total score CI probability &amp;lt;-0.1 High probaility 0.2-0.6 Intermediate probability &amp;gt;0.6 Low probability

Protective Role of Moolabandha While Practicing Bhastrika and Kapalabhati by Women Vulnerable to Bladder Dysfunction: A Preliminary Ultrasound Study.

Aim:Obstetrical trauma and chronic exposure to increased intraabdominal pressure (IIAP) are known to increase vulnerability toward stress urinary incontinence. Bhastrika and Kapalabhati being fast yogic breathing maneuvers (FYBM), their association with IIAP is likely. Therefore, a preliminary descriptive study was conducted using transabominal ultrasound mode, to find whether impact of FYBM reinforced by prevailing risk factors had any adverse effect on the bladder neck status and urethral mobility of female yogic practioners and whether simultaneous application of Moolabandha inhibited such impact.Material:Mindray DC N3 model of diagnostic ultrasound unit with M probe was used for assessment.Methods:This study included 15 heterogenous female yoga teachers having average age, years of practice, and body mass index as 42.7 years, 7.33 years, and 24.86 kg/m2, respectively. Retrovesical angle (RVA) and posterior displacement (PD) and inferior displacement (ID) of urthetrhra were assessed while performing Bhastrika and Kapalabhati maneuvers with and without applying Moolabandha. Data obtained were then used for descriptive analysis.Results:Analysis showed a mixed picture, i.e., negative impact as well as preservation of protective strain-levator reflex in certain variables while practicing FYBM. Complicated labor and practice of power yoga appeared to reinforce the impact of FYBM. The values of RVA as well as PD and ID dropped and were statistically significant when FYBM was performed with Moolabandha. Aging factor, uneventful vaginal labor, or obesity could not confirm as prevailing risk factors.Conclusion:Moolbandha proved its protective behavior while practicing Bhastrika and Kapalabhati by vulnerable women.

Hyperventilation-induced heart rate response as a potential marker for cardiovascular disease

An increase of heart rate to physical or mental stress reflects the ability of the autonomous nervous system and the heart to respond adequately. Hyperventilation is a user-controlled breathing maneuver that has a significant impact on coronary function and hemodynamics. Thus, we aimed to investigate if the heart rate response to hyperventilation (HRRHV) can provide clinically useful information. A pooled analysis of the HRRHV after 60 s of hyperventilation was conducted in 282 participants including healthy controls; patients with heart failure (HF); coronary artery disease (CAD); a combination of both; or patients suspected of CAD but with a normal angiogram. Hyperventilation significantly increased heart rate in all groups, although healthy controls aged 55 years and older (15 ± 9 bpm) had a larger HRRHV than each of the disease groups (HF: 6 ± 6, CAD: 8 ± 8, CAD+/HF+: 6 ± 4, and CAD−/HF−: 8 ± 6 bpm, p < 0.001). No significant differences were found between disease groups. The HRRHV may serve as an easily measurable additional marker of cardiovascular health. Future studies should test its diagnostic potential as a simple, inexpensive pre-screening test to improve patient selection for other diagnostic exams.

The upper frequency limit of dynamic cerebral autoregulation.

Dynamic cerebral autoregulation (CA) is expressed by the temporal pattern of cerebral blood flow (CBF) recovery following a sudden change in arterial blood pressure (BP). Transfer function analysis of BP as input and CBF velocity as output can express dynamic CA through its amplitude (or gain) and phase frequency responses. The upper frequency limit (FupLim ) at which dynamic CA can operate is of considerable physiological interest and can also provide additional information about worsening CA due to disease processes. In healthy subjects FupLim was strongly dependent on arterial changes induced by four different breathing manoeuvres. The considerable intersubject variability in FupLim suggests that fixed frequency bands should not be adopted for averaging values of gain and phase in studies of dynamic CA. Dynamic cerebral autoregulation (CA) can be expressed in the frequency domain by the amplitude and phase frequency responses calculated by transfer function analysis of arterial blood pressure (BP) and cerebral blood flow velocity (CBFV). We studied the effects of arterial ( ) on the upper frequency limit (FupLim ) of these responses and its intersubject variability. Twenty-four healthy subjects (11 female, age 36.0±13.4years) were recruited. Recordings of CBFV (transcranial Doppler ultrasound), BP (Finometer) and end-tidal CO2 ( , capnography) were performed during 5min at rest (normocapnia) and during four breathing manoeuvres: 5% and 8% CO2 in air and hyperventilation targeting reductions of 5 and 10mmHg compared to normocapnia. FupLim was determined by the break point of the autoregulation index (ARI) curve as a function of frequency when the phase response was gradually set to zero. The five breathing conditions led to highly significant differences in (p<0.0001), CBFV (P<0.0001), ARI (p<0.0001) and FupLim (p<0.0001). FupLim ranged from 0.167±0.036Hz at the lowest values of hypocapnia (28.1±1.9mmHg) to 0.094±0.040Hz at the highest level of hypercapnia (41.7±5.4mmHg), showing a correlation of r=-0.53 (p<0.001) with . These findings reinforce the key role of in CBF regulation. The considerable intersubject variability of FupLim suggests that fixed frequency bands should not be adopted for averaging values of gain and phase in dynamic CA studies, and that the higher frequency band (0.20-0.40Hz), in particular, does not contain relevant information about dynamic CA. Further investigations are needed to assess the information value of FupLim as a marker of dynamic CA efficiency in physiological and clinical studies.

Efficacy of Paced Breathing at the Low-frequency Peak on Heart Rate Variability and Baroreflex Sensitivity.

We developed a simple method for identifying resonance frequency by focusing on the spectral peak of the low-frequency (LF) component of heart rate variability (HRV) and examined the hypothesis that paced breathing at an accurate resonance frequency increases HRV and baroreflex sensitivity (BRS). We assessed a peak frequency of the LF component of the resting HRV by using power spectral analysis under respiratory control at 0.25Hz, and a resonance frequency, which was evaluated by using the standard breathing maneuver (Lehrer 2007). We examined the effects of paced breathing at the peak frequency of the LF component (Spectral condition) and paced breathing at the resonance frequency as determined by the standard breathing maneuver (Standard condition) on HRV and BRS in 28 healthy college students and young adults. Electrocardiogram, respiration, and noninvasive continuous blood pressure was recorded during a 5-min baseline, followed by a 5-min paced breathing session. Results indicated that the BRS increased during the breathing session under both conditions, but the increase in BRS under the Spectral condition was higher than the Standard condition (p < .05). The LF amplitude increased during the breathing session under both conditions (p < .001), although the difference between the conditions was not significant. These results suggest that paced breathing at the peak frequency of the LF component enhanced the autonomic baroreflex function. Moreover, assessment of the LF-peak may provide more accurate information on resonance frequency for paced breathing during HRV biofeedback.

Effects of Radiotherapy in Coronary Artery Disease.

This review describes the effects of radiotherapy (RT) on coronary artery disease, its mechanisms, and clinical and laboratory evidence and discusses ways to minimize radiation-induced coronary atherosclerosis. Radiation-induced cardiac toxicity is known in patients undergoing thoracic RT. One of the damages occurs in the coronary arteries, with accelerated atherosclerosis manifesting decades later. There is clinical and laboratory evidence of coronary damage in retrospective studies, systematic reviews, and meta-analyses. Clinical studies have shown that RT cardiotoxicity occurs decades after radiation, regardless of chemotherapy, and may occur earlier in patients with pre-existing risk factors or disease. The pathogenesis of radiation-induced coronary artery disease is complex and multifactorial, including endothelial dysfunction, altered vascular tone, hemostatic imbalance, and inflammatory activation. Some factors are responsible, such as mean heart dose, RT chest site, patient position, techniques, and breathing maneuvers. There are approaches to reduce radiation-induced cardiac toxicity. Among them, besides the mentioned factors, metformin and anti-inflammatory agents can minimize coronary damage, with impact on morbidity and mortality.

Effect of Breathing Maneuvers on Peripheral Glucose Metabolism

Effect of Breathing Maneuvers on Peripheral Glucose Metabolism

Monitoring of Volume of Air in Inhalation From Triflo Using Video Processing

Breathing exercise training with a flow-oriented incentive spirometer (or Triflo) is important in lung expansion rehabilitation for patients with lung surgery or pulmonary injury. In this article, we propose a novel technique to estimate the volume of air inhaled and the sustained inhalation time based on video processing. The proposed technique combines a randomized circle detection algorithm to detect the three balls in Triflo tubes and a normalized cross-correlation algorithm to track these three balls that rise due to inhalation. The values of inhalation and the sustained inhalation time intervals are automatically recorded as screenshots on a personal computer for later analysis by a doctor. Three major experiments were conducted to verify the advantages of this proposed system. The first experiment evaluated the performances of both the ball detection and the tracking algorithms showing 3.68% error. The second experiment applied the proposed method implemented, so that it displays in plots the changes in the inhalation rate, as the training of a postoperative volunteer progressed. In the last experiment, a healthy subject employs Triflo to test the inhalation training format for lung volume regeneration with three levels of difficulty, to record the number of successful breathing maneuvers. When the data are displayed in rate versus time plots, a graph can help a doctor to appropriately plan the training program for the benefit of patients, because a more adaptable therapy can be realized and varying degrees of difficulty can be implemented. In addition, the patients can comfortably practice in home-based rehabilitation, seeing the improvements in the inspiratory muscle performance in computer screenshots.

P2718Interim study: analysis of myocardial deformation using fSENC-CMR on patients with chest pain

Abstract Background In acute situations such as non-ST-elevation infarction (NSTEMI) or relevant coronary artery disease (CAD) CMR does not yet play a key role due to its lengthy protocols. fSENC is a new CMR technique which may detect subclinical signs of myocardial damage by measuring myocardial strain (change in length/ unit length). A whole-heart coverage is generated in 6 heart-beats and the information obtained is converted into a colour-coded map. fSENC does not require major post-processing, long breath-holds and the administration of contrast agents/medication. Purpose In this observational study fSENC is assessed in patients with chest pain and its capability to differentiate between an ischemic cause (NSTEMI, significant CAD), an underlying non-ischemic cardiac disease and non-cardiac chest pain. Additionally, we aim to identify the affected coronary arteries in the ischemic cohort. With fSENC it could be possible to successfully diagnose patients with suspected AMI in &lt;1h after admission and also gain diagnostic information regarding the underlying pathology. Methods Patients with chest pain and an initial hscTnT level between 5pg/ml and 52 pg/ml are recruited. These patients then undergo an fSENC-CMR before 2nd hscTnT measurement. Additionally, a stress-induced fSENC-image is acquired (1-minute hyperventilation, followed by a single breath-hold). This breathing manoeuvre leads to an increase in oxygenation through vasodilation, therefore identifying ischemic areas. The fSENC analysis is later compared to the patient's final diagnosis and therapy. Results So far 50 patients have been analysed by fSENC in this observational study (26 female, aged 57±18). fSENC correctly identified 7 patients suffering from NSTEMI or significant CAD and their affected coronary arteries. 42 other patients were safely ruled-out by fSENC which was consistent with the serial hscTnT results. In 11 patients fSENC was able to detect generalized impaired myocardial deformation, implying an underlying cardiac disease (hypertrophic cardiomyopathy, myocarditis). fSENC currently exhibits a sensitivity of 100% and specificity of 97,7% for correct rule-in/-out of an ischemic cause. Conclusions At this stage fSENC allows correct identification of patients suffering from myocardial infarction and their affected coronary arteries. Additionally, fSENC can safely rule-out patients with chest pain but no underlying ischemic cause. This novel technique is a rapid additional diagnostic tool which assesses myocardial function non-invasively without radiation exposure.

ASSESSMENT OF THE DIAGNOSTIC VALUE OF THE METHOD OF COMPUTER OLFACTOMETRY

Olfactory studies can be a criterion for evaluating rhinosurgical intervention, and olfactory impairment may indicate respiratory impairment. Therefore, the urgent task is to develop an integrated approach to determining respiratory and olfactory disorders. A structural scheme was developed for the method of objective diagnosis of respiratory and olfactory disorders, taking into account the measu, rement of both the aerodynamic parameters of nasal breathing and the calculation of energy characteristics, which are used to determine olfactory sensitivity. The diagnostic significance of the proposed method of analyzing rhinofolipometry data with regard to additional parameters was assessed - it is necessary to take into account the time and power of breathing when the threshold of sensation of the odorivector is at the transition point of the airflow mode to the turbulent quadratic. It has been established that it is advisable to use the energy criteria of nasal breathing, pneumatic power and energy of nasal breathing under the action of the corresponding odor vector for the assessment of respiratory impaired olfactory. To assess the respiratory impairment of olfactory, it is necessary to use the method in which an odor vector is installed in the air path of the rhinomanometer, and the patient is asked to perform breathing maneuvers with a consistent increase in respiration rate while fixing the time at which olfactory sensitivity is achieved and then determining the respiratory energy characteristics. A statistical processing of diagnostic results was carried out, which confirms the adequacy of the model of independent statistical verification and makes it possible to use this method for the functional diagnosis of respiratory-olfactory disorders and testing of respiratory-olfactory sensitivity. The probability index of the error of the second kind is 0.17.

Shortening of airway smooth muscle is modulated by prolonging the time without simulated deep inspirations in ovine tracheal strips.

The shortening of airway smooth muscle (ASM) is greatly affected by time. This is because stimuli affecting ASM shortening, such as bronchoactive molecules or the strain inflicted by breathing maneuvers, not only alter quick biochemical processes regulating contraction but also slower processes that allow ASM to adapt to an ever-changing length. Little attention has been given to the effect of time on ASM shortening. The present study investigates the effect of changing the time interval between simulated deep inspirations (DIs) on ASM shortening and its responsiveness to simulated DIs. Excised tracheal strips from sheep were mounted in organ baths and either activated with methacholine or relaxed with isoproterenol. They were then subjected to simulated DIs by imposing swings in distending stress, emulating a transmural pressure from 5 to 30 cmH2O. The simulated DIs were intercalated by 2, 5, 10, or 30 min. In between simulated DIs, the distending stress was either fixed or oscillating to simulate tidal breathing. The results show that although shortening was increased by prolonging the interval between simulated DIs, the bronchodilator effect of simulated DIs (i.e., the elongation of the strip post- vs. pre-DI) was not affected, and the rate of re-shortening post-simulated DIs was decreased. As the frequency with which DIs are taken increases upon bronchoconstriction, our results may be relevant to typical alterations observed in asthma, such as an increased rate of re-narrowing post-DI.NEW & NOTEWORTHY The frequency with which patients with asthma take deep inspirations (DIs) increases during bronchoconstriction. This in vitro study investigated the effect of changing the time interval between simulated DIs on airway smooth muscle shortening. The results demonstrated that decreasing the interval between simulated DIs not only decreases shortening, which may be protective against excessive airway narrowing, but also increases the rate of re-shortening post-simulated DIs, which may contribute to the increased rate of re-narrowing post-DI observed in asthma.

Heart rate variability analysis and cardiac dysautonomia in ischemic stroke patients

ObjectivesAutonomic nervous system dysfunction after ischemic stroke predisposes to cardiovascular complications. We aimed to investigate cardiac autonomic activity in ischemic stroke patients using heart rate variability analysis, illustrating the sympathovagal balance at different sympathetic and parasympathetic activation tests. Patients and methodsWe studied the dynamics of the linear and non-linear heart rate variability parameters in 31 left and 40 right middle cerebral artery ischemic stroke patients in rest condition and during autonomic activation tests (handgrip, standing, deep breathing and Valsalva maneuver). Data were compared with 30 age- and sex-matched healthy controls. ResultsWe found different responses after autonomic activation tests in stroke patients depending on the cortical lateralization of the ischemic lesion. In resting state, left hemisphere stroke patients presented enhanced parasympathetic modulation of the heart rate (higher values for RMSSD, pNN50, HF and SD1, p < 0.05), comparing to right hemisphere stroke patients. This second group displayed a reduced cardiac parasympathetic control in resting state and during autonomic activation tests (handgrip and standing tests) compared to the left hemisphere stroke group and controls. Non-linear parameters SD1 and DFA α1 showed a decrease of variability and complexity of the heart rate in right hemisphere stroke patients, ameliorated during vagal activation tests. ConclusionTo prevent possible complications with vital risk, assessment of cardiovascular autonomic activity becomes a necessary stage in stroke patient management, facilitating immediate implementation of preventive and therapeutic strategies. Heart rate variability analysis in resting state and during autonomic activation tests allows identifying patients prone to sympathetic hyperactivity. New therapeutic perspectives for stroke management may emerge founded on the modulation of the autonomic nervous system.