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514 result(s) for "Exhalation - physiology"
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Different effects of inspiratory duration and expiratory duration on heart rate deceleration capacity and heart rate asymmetry
PurposeLow values of heart rate deceleration capacity (DC) and heart rate asymmetry (HRA) are associated with cardiovascular risks. Slow respiration has been proven to enhance the magnitudes of these indexes, but individual inspiratory (TI) and expiratory (TE) durations were not controlled in most studies. This study aims to examine whether the effects of TI and TE on these indexes would be the same and, if not, how to adjust TI and TE to maximize the effect of slow respiration.MethodsWe evaluated 14 seated healthy young adults who randomly controlled their breathing to nine combinations of TI and TE, each chosen respectively from 2, 4, and 6 s. A 5-min R-R interval time series was obtained from each study period for further analysis.ResultsThe magnitude of DC increased when TI or TE increased, while that of acceleration capacity (AC) remained almost unchanged by TI. We further defined a new index as 100 × DC2/(DC2 + AC2) and found it to be correlated with conventional Guzik’s (r = 0.94) and Porta's (r = 0.99) indexes of HRA during different combinations of TI and TE. Increasing TI and increasing TE both enhanced the magnitudes of HRA indexes, with TI taking effect when ≤ 4 s, and TE taking effect when > 4 s. DC and HRA indexes were maximized with a TI of 4 s and a TE of 6 s.ConclusionWe suggest that a TI of 3–4 s with a TE of 7–6 s is an appropriate standard for slow respiration.
Combination of inspiratory and expiratory muscle training in same respiratory cycle versus different cycles in COPD patients: a randomized trial
Background Difference between combined inspiratory and expiratory muscle training in same respiratory cycle or different cycles remained unclarified. We explored the difference between both patterns of combined trainings in patients with COPD. Methods In this randomized, open-label, controlled trial, stable COPD subjects trained for 48 minutes daily, for 8 weeks, using a monitoring device for quality control. Ninety-two subjects were randomly and equally assigned for sham training, inspiratory muscle training(IMT), combined inspiratory and expiratory muscle training in same cycle(CTSC) or combined inspiratory and expiratory muscle training in different cycles(CTDC). Respiratory muscle strength, as the primary endpoint, was measured before and after training. Registry: ClinicalTrials.gov (identifier: NCT02326181). Results Respiratory muscle training improved maximal inspiratory pressure(PImax), while no significant difference was found in PImax among IMT, CTSC and CTDC. Maximal expiratory pressure(PEmax) in CTSC and CTDC was greater than IMT( P = 0.026, and P =0.04, respectively) and sham training ( P = 0.001). IMT, CTSC, and CTDC shortened inhalation and prolonged exhalation( P < 0.01). Subjects with respiratory muscle weakness in IMT and CTDC exhibited greater increase in PImax than those without. IMT, CTSC and CTDC showed no difference in symptoms and quality of life scales among themselves( P > 0.05). Conclusion Both patterns of CTSC and CTDC improved inspiratory and expiratory muscle strength, while IMT alone only raised PImax. Respiratory muscle training might change the respiratory cycles, and be more beneficial for COPD patients with inspiratory muscle weakness.
Effects of CPAP therapy withdrawal on exhaled breath pattern in obstructive sleep apnoea
BackgroundObstructive sleep apnoea (OSA) is highly prevalent and associated with cardiovascular and metabolic changes. OSA is usually diagnosed by polysomnography which is time-consuming and provides little information on the patient's phenotype thus limiting a personalised treatment approach. Exhaled breath contains information on metabolism which can be analysed by mass spectrometry within minutes. The objective of this study was to identify a breath profile in OSA recurrence by use of secondary-electrospray-ionization-mass spectrometry (SESI-MS).MethodsPatients with OSA effectively treated with CPAP were randomised to either withdraw treatment (subtherapeutic CPAP) or continue therapeutic CPAP for 2 weeks. Exhaled breath analysis by untargeted SESI-MS was performed at baseline and 2 weeks after randomisation. The primary outcome was the change in exhaled molecular breath pattern.Results30 patients with OSA were randomised and 26 completed the trial according to the protocol. CPAP withdrawal led to a recurrence of OSA (mean difference in change of oxygen desaturation index between groups +30.3/h; 95% CI 19.8/h,40.7/h, p<0.001) which was accompanied by a significant change in 62 exhaled features (16 metabolites identified). The panel of discriminating mass-spectral features allowed differentiation between treated and untreated OSA with a sensitivity of 92.9% and a specificity of 84.6%.ConclusionExhaled breath analysis by SESI-MS allows rapid and accurate detection of OSA recurrence. The technique has the potential to characterise an individual's metabolic response to OSA and thus makes a comprehensible phenotyping of OSA possible.Trial registration numberNCT02050425 (registered at ClinicalTrials.gov).
Does inspiratory muscle training affect expiratory muscle thickness in respiratory intensive care patients? A pilot randomized controlled study
This randomized controlled trial aimed to compare abdominal muscle thickness between intensive care patients and healthy controls, and to evaluate the impact of IMT on expiratory muscle thickness using ultrasound. In this single-blind randomized controlled trial, 20 post-extubation intensive care patients were randomly assigned to either an a conventional physiotherapy (CP) group or IMT + CP group. Both interventions were applied for five days. An additional 10 healthy individuals served as controls for comparison. Abdominal muscle thicknesses—including external oblique (EOA), internal oblique (IOA), transversus abdominis (TRA), and rectus abdominis (RA)—were measured using ultrasound. Maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) were also recorded. At baseline, healthy controls had significantly higher MIP, MIP% predicted, MEP, MEP% predicted, and RA muscle thickness compared to both patient groups (p < 0.05). Following intervention, both IMT and CP groups showed significant improvements in MIP (p < 0.05), but only the IMT group demonstrated significant increases in MEP, MEP% predicted, IOA, and RA muscle thickness (p < 0.05). The IMT group showed significantly greater improvements in MIP, MEP, IOA, and RA muscle thickness compared to the CP group (p < 0.05). Post-extubation IMT may improve not only inspiratory but also expiratory muscle strength and abdominal wall thickness. These findings suggest that IMT could support weaning processes in intensive care, although larger studies are needed. •Rectus abdominis thickness, MIP, MIP% predicted, MEP and MEP% predicted are higher in the healthy individiuals than in ICU patients•IMT increasesinternal oblique and rectus abdominis thickness in respiratory ICU patients.•IMT improves both MIP,MEPand predict
Vagally Mediated Heart Rate Variability and Mood States in Patients with Chronic Pain Receiving Prolonged Expiration Regulated Breathing: A Randomized Controlled Trial
Reduced vagally mediated heart rate variability (VmHRV) has been reported in patients with chronic pain. In healthy persons, breathing with longer expiration relative to inspiration increases VmHRV at 12 breaths per minute. The present study aimed to determine the immediate effect of breathing with longer expiration relative to inspiration on VmHRV and mood states in patients with chronic pain. Fifty patients with chronic pain aged between 20 and 67 years were prospectively randomized as two groups with an allocation ratio of 1:1. The interventional group practiced breathing with metronome based visual cues, maintaining an inspiration to expiration ratio of 28:72 (i/e ratio, 0.38) at a breath rate of 12 breaths per minute. The average i/e ratio they attained based on strain gauge respiration recording was 0.685 (SD 0.48). The control group, which looked at the metronome without conscious breath modification had an average i/e ratio of 0.745 (SD 0.69). The VmHRV, respiration and self-reported mood states (using the Brief Mood Introspection Scale (BMIS)) were assessed. There was a significant increase in HF-HRV and RMSSD during low i/e breathing (repeated measures ANCOVA, Bonferroni adjusted post-hoc test, p < 0.05; in all cases). Self-reported mood states changed as follows: (i) following low i/e breathing positive-mood states increased while the aroused mood state decreased whereas (ii) following the control intervention the aroused mood state increased (repeated measure ANOVA, p < 0.05; in all cases). Hence breathing with prolonged expiration is possibly useful to increase VmHRV and improve self- reported mood states in patients with chronic pain.
Carbon monoxide levels after inhalation from new generation heated tobacco products
Heated tobacco products (HTPs) are new tech devices that release nicotine and other volatile compounds into an inhalable aerosol by heating the tobacco . At their operating temperatures, tobacco combustion is unlikely. The aim of this randomized cross-over study was to measure the exposure levels of the combustion marker, carbon monoxide in the exhaled breath (eCO) of subjects after use of two HTPs and to compare these levels with participants’ own brand of cigarettes. A total of 12 healthy smokers who reported smoking ≥10 conventional cigarettes per day for at least 5 years took part in the study. Product administration consisted of a first round of 10 puffs, which was followed by an identical second round after a 5 min pause in between rounds. After obtaining a baseline eCO value, this measure was recorded at 5, 10, 15, 30, and 45 min after the first puff of the first round. In contrast to combustible cigarettes, no eCO elevations were observed in the exhaled breath after use of the HTPs under investigation in any of the study participants.
Validation of the Better Care® system to detect ineffective efforts during expiration in mechanically ventilated patients: a pilot study
Purpose Ineffective respiratory efforts during expiration (IEE) are a problem during mechanical ventilation (MV). The goal of this study is to validate mathematical algorithms that automatically detect IEE in a computerized (Better Care ® ) system that obtains and processes data from intensive care unit (ICU) ventilators in real time. Methods The Better Care ® system, integrated with ICU health information systems, synchronizes and processes data from bedside technology. Algorithms were developed to analyze airflow waveforms during expiration to determine IEE. Data from 2,608,800 breaths from eight patients were recorded. From these breaths 1,024 were randomly selected. Five experts independently analyzed the selected breaths and classified them as IEE or not IEE. Better Care ® evaluated the same 1,024 breaths and assigned a score to each one. The IEE score cutoff point was determined based on the experts’ analysis. The IEE algorithm was subsequently validated using the electrical activity of the diaphragm (EAdi) signal to analyze 9,600 breaths in eight additional patients. Results Optimal sensitivity and specificity were achieved by setting the cutoff point for IEE by Better Care ® at 42%. A score >42% was classified as an IEE with 91.5% sensitivity, 91.7% specificity, 80.3% positive predictive value (PPV), 96.7% negative predictive value (NPV), and 79.7% Kappa index [confidence interval (CI) (95%) = (75.6%; 83.8%)]. Compared with the EAdi, the IEE algorithm had 65.2% sensitivity, 99.3% specificity, 90.8% PPV, 96.5% NPV, and 73.9% Kappa index [CI (95%) = (71.3%; 76.3%)]. Conclusions In this pilot, Better Care ® classified breaths as IEE in close agreement with experts and the EAdi signal.
Lung-protective properties of expiratory flow-initiated pressure-controlled inverse ratio ventilation: A randomised controlled trial
Expiratory flow-initiated pressure-controlled inverse ratio ventilation (EF-initiated PC-IRV) reduces physiological dead space. We hypothesised that EF-initiated PC-IRV would be lung protective compared with volume-controlled ventilation (VCV). Twenty-eight men undergoing robot-assisted laparoscopic radical prostatectomy were enrolled in this randomised controlled trial. The EF-initiated PC-IRV group (n = 14) used pressure-controlled ventilation with the volume guaranteed mode. The inspiratory to expiratory (I:E) ratio was individually adjusted by observing the expiratory flow-time wave. The VCV group (n = 14) used the volume control mode with a 1:2 I:E ratio. The Mann-Whitney U test was used to compare differences in the serum cytokine levels. There were no significant differences in serum IL-6 between the EF-initiated PC-IRV (median 34 pg ml-1 (IQR 20.5 to 63.5)) and VCV (31 pg ml-1 (24.5 to 59)) groups (P = 0.84). The physiological dead space rate (physiological dead space/expired tidal volume) was significantly reduced in the EF-initiated PC-IRV group as compared with that in the VCV group (0.31 ± 0.06 vs 0.4 ± 0.07; P<0.001). The physiological dead space rate was negatively correlated with the forced vital capacity (% predicted) in the VCV group (r = -0.85, P<0.001), but not in the EF-initiated PC-IRV group (r = 0.15, P = 0.62). Two patients in the VCV group had permissive hypercapnia with low forced vital capacity (% predicted). There were no differences in the lung-protective properties between the two ventilatory strategies. However, EF-initiated PC-IRV reduced physiological dead space rate; thus, it may be useful for reducing the ventilatory volume that is necessary to maintain normocapnia in patients with low forced vital capacity (% predicted) during robot-assisted laparoscopic radical prostatectomy.
Effect of a prolonged slow expiration technique on 24-h food intake in children hospitalized for moderate bronchiolitis: a randomized controlled trial
Background Chest physiotherapy for airway clearance is not recommended in children hospitalized with bronchiolitis. The updated Cochrane meta-analysis suggests that slow expiratory techniques could slightly improve clinical severity, but the evidence certainty is low and the clinical significance of this change is unknown. We investigated whether the prolonged slow expiration technique (PSET) would impact the 24-h food intake of these children. Methods We conducted a two-arm double-blind randomized controlled trial. Hospitalized children aged from 1 to 12 months, bottle-fed or diversified and referred for airway clearance were included. Both groups received upper airway clearance at inclusion and standard treatments. The experimental group received PSET including rhinopharyngeal unclogging and targeted unprovoked cough. The primary outcome was the 24-h food intake. Clinical severity, vomit episodes and sleep quality were also recorded. An ordinary least squares linear regression for quantitative variables was modelled for between-group comparisons. Results From January 9, 2019, to December 1, 2022, 42 children were randomized with a 1:1 ratio (mean age: 5.0 (± 2.9) months). The 24-h food intake did not differ between groups (estimate: 1.8% (95%CI -7.0 to 10.6); p  = 0.68). PSET had no effect on SpO2, clinical severity, RR and HR at the follow-up assessments (5 min, 30 min and 24 h after intervention), nor on the number of vomit episodes, total sleep time and SpO2 during sleep. Conclusions PSET did not affect food intake or the 24-h course of bronchiolitis more than standard treatment in children hospitalized for moderate bronchiolitis. Trial registration NCT03738501  registered on 13/11/2018, Slow Expiratory Technique to Improve Alimentation in Children With Bronchiolitis (BRONCHIOL-EAT); https://classic.clinicaltrials.gov/ct2/show/NCT03738501.
Comparing patterns of volatile organic compounds exhaled in breath after consumption of two infant formulae with a different lipid structure: a randomized trial
Infant formulae have been used since decades as an alternative to or a complement to human milk. Human milk, the “gold standard” of infant nutrition, has been studied for its properties in order to create infant formulae that bring similar benefits to the infant. One of the characteristics of milk is the size of the lipid droplets which is known to affect the digestion, gastric emptying and triglyceride metabolism. In the current study a concept infant milk formula with large, phospholipid coating of lipid droplets (mode diameter 3–5 μm; NUTURIS, further described as “active”), was compared to a commercially available formula milk characterised by smaller lipid droplets, further described as “control” (both products derived from Nutricia). We investigated whether we could find an effect of lipid droplet size on volatile compounds in exhaled air upon ingestion of either product. For that purpose, exhaled breath was collected from a group of 29 healthy, non-smoking adult males before ingestion of a study product (baseline measurements, T0) and at the following time points after the test meal: 30, 60, 120, 180 and 240 min. Volatile organic compounds (VOCs) in breath were detected by gas chromatography- time-of-flight -mass spectrometry. Any differences in the time course of VOCs patterns upon intake of active and control products were investigated by regularised multivariate analysis of variance (rMANOVA). The rMANOVA analysis revealed statistically significant differences in the exhaled breath composition 240 min after ingestion of the active formula compared to control product (p-value < 0.0001), but did not show significant changes between active and control product at any earlier time points. A set of eight VOCs in exhaled breath had the highest contribution to the difference found at 240 minutes between the two formulas. A set of ten VOCs was different between baseline and the two formulae at T240 with p-value < 0.0001. To our knowledge this is the first study that shows the ability of VOCs in exhaled breath to monitor metabolic effects after ingestion of infant formulae with different lipid structure. The statistically significant differences in compound abundance found between active and control formula milk may be related to: (i) specific differences in the digestion, (ii) absorption of lipids and proteins and (iii) assimilation of the products in the gut.