Validation of a breath-holding test as a screening test for exercise-induced hypoxemia in chronic respiratory diseases.
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ABSTRACT:
SUBMITTER: Ideguchi H
PROVIDER: S-EPMC8718165 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ObjectivesCardiopulmonary involvement is a major cause of death in patients with SSc. This study evaluated the clinical utility and reliability of breath-holding test (BHT) in evaluating cardiopulmonary function in patients with SSc.MethodsSeventy-two prospectively enrolled patients with SSc underwent BHT and the 6 min walk test (6MWT), along with measurements of the Borg dyspnoea scale and Scleroderma Health Assessment Questionnaire (SHAQ). Data on pulmonary function test and echocardiography were also collected. Validity was assessed based on the correlations between the best BHT and relevant clinical parameters. To assess the reliability of BHT, an additional 31 patients with SSc underwent BHTs twice within 2 week intervals.ResultsMean (s.d.) best BHT time was 38.4 (15.7) s, and 6MWT distance was 473.5 (95.5) m. BHT showed significant correlations with the Borg dyspnoea scale before (r = -0.367, P < 0.001) and after (r = -0.285, P = 0.016) testing, whereas 6MWT were correlated with the Borg dyspnoea scale after (r = -0.351, P = 0.002) but not before (r = -0.113, P = 0.343) testing. BHT time was correlated with diffusing capacity for carbon monoxide (%, r = 0.426, P < 0.001), forced vital capacity (litres, r = 0.373, P = 0.001), pulmonary arterial systolic pressure (mmHg, r = -0.272, P = 0.031) and SHAQ score (r = -0.470, P < 0.001), but not with left ventricular ejection fraction (%, r = -0.135, P = 0.263). BHT showed excellent reliability, with an intraclass correlation coefficient (2, 1) of 0.943 (95% CI: 0.88, 0.97).ConclusionBHT, a simple and less time-consuming test, shows excellent reliability and significant correlation with the Borg scale, SHAQ and pulmonary parameters. These results suggest that BHT might be a useful surrogate marker of pulmonary capacity in SSc patients.Trial registration numberNCT04484948.
| S-EPMC9536778 | biostudies-literature
Project description:In this study, we examined how time perception, a psychological factor, impacts the physiological response to prolonged, voluntary breath holding. Participants (n = 26) held their breath while watching a distorted timer that made it appear as though time was moving up to 40% faster or slower than real time. We monitored total breath-holding duration under different time manipulation conditions as well as the onset of involuntary breathing movements. This physiological breaking point marks the end of the "easy-going" phase of apnea and the start of the "struggle" phase. Based on prior work showing that psychological factors, such as attention and motivation, can influence the length of the struggle phase, we hypothesized that manipulating the perception of time would affect overall breath-holding duration by changing the duration of the struggle phase, but not the easy-going phase. We found that time perception can be successfully manipulated using a distorted timekeeper, and total breath-holding duration correlated with perceived time, not actual time. Contrary to our hypothesis, this effect was attributable to changes in the onset of the physiological breaking point, not changes in the length of the struggle phase. These results demonstrate that unconscious psychological factors and cognitive processes can significantly influence fundamental physiological processes.
| S-EPMC6908740 | biostudies-literature
Project description:Supplemental oxygen (SO) increases survival in hypoxemic patients. In hypoxia, mammals respond by modulating O2-sensitive transducers that stabilize the transcription factor hypoxia-inducible factor-1-alpha (HIF-1α), which transactivates the genes that govern angiogenesis and metabolic pathways. Residing at high altitudes exposes millions of people to hypoxemia with potential adverse consequences on their health. We aimed to identify markers of hypoxemia that can be used in the evaluation of patients in addition to pulse oximetry and arterial blood gases, especially those that could respond after 1 month of oxygen use. We performed a prospective pilot study at 2240 m above sea level, with repeated measurements before and after (b/a) 1-month home oxygen therapy in 70 patients with lung diseases, of which 24/20 have COPD, 41/39 obstructive sleep apnea (OSA), and 5/2 with interstitial lung diseases (ILD), all of them having chronic hypoxemia, as well as 70 healthy subjects as controls. Proteins evaluated included HIF-1α, vascular endothelial growth factor (VEGF), and erythropoietin (EPO). Among the main results, we found that hypoxemic patients had normal levels of HIF-1α but increased EPO compared with healthy controls. VEGF levels were heterogeneous in the sample studied, similar to the control group in COPD, slightly increased in OSA, and decreased in fibrosis. With oxygen treatment, the HIF-1α and EPO decreased in COPD and OSA but not in fibrosis, and VEGF remained constant over time. In conclusion, erythropoietin and HIF-1α identified hypoxemia initially and responded to oxygen. In pulmonary fibrosis, HIF-1α, EPO, and VEGF increased with oxygen therapy, which is likely linked to the disease's pathogenesis and clinical course rather than hypoxemia.
| S-EPMC8150591 | biostudies-literature
Project description:ObjectiveThe molecular pathways underlying hypoxemia-induced alterations in neurodevelopment of infants with congenital heart disease have not been delineated. We used transcriptome analysis to investigate differential gene expression induced by hypoxemia in an ovine artificial-womb model.MethodsMid-gestation fetal sheep (median [interquartile range] 109 [107-112] days' gestation) were cannulated via the umbilical vessels, attached to a pumpless, low-resistance oxygenator circuit, and incubated in a sterile, fluid environment for 22 [21-23] days. Fetuses were maintained with an oxygen delivery of 20-25 mL/kg/min (normoxemia, n = 3) or 14-16 mL/kg/min (hypoxemia, n = 4). Transcriptional profiling by RNA sequencing was carried out on left frontal brains and hypoxemia-regulated genes were identified by differential gene expression analysis.ResultsA total of 228 genes whose expression was up or down regulated by ≥1.5-fold (false discovery rate ≤0.05) were identified. The majority of these genes were induced in hypoxemic animals compared to normoxemic controls, and functional enrichment analysis identified respiratory electron transport as a pathway strongly upregulated in the brain during chronic hypoxemia. Further examination of hypoxemia-induced genes showed robust induction of all 7 subunits of the mitochondrial NADH:ubiquinone oxidoreductase (complex I). Other hypoxemia-induced genes included cytochrome B, a component of complex III, and ATP6, ATP8, both of which are components of complex V.ConclusionsChronic fetal hypoxemia leads to upregulation of multiple mitochondrial respiratory complex genes critical for energy production and reactive oxygen species generation, including complex I. These data provide valuable insight into potential pathways involved in chronic hypoxemia-induced neuropathology and offers potential therapeutic targets for fetal neuroprotection in fetuses with congenital heart defects.
| S-EPMC9390414 | biostudies-literature
Project description:Breath holding (BH) endurance has been suggested as a measure of the distress tolerance that could predict the outcome of attempts to implement behavior changes, such as stopping smoking or illicit substance use. It is not known however, to what degree BH endurance is a variable trait that may vary depending on situational context, or a stable state characteristic. We measured BH in two groups of participants at baseline and 22 and 89 days (N = 62 and N = 41) post-baseline and in a third group at multiple times points across a 5-week period (N = 44). Participants also filled out a questionnaire created to assess their perceived persistence compared to peers. Correlations were found between baseline and final BH measures (r's > 0.67, p's < 0.0001) at all time points. When groups were combined, regardless of time point, Spearman's rank correlation showed a strong positive correlation (rs = 0.66, p < 0.0001). Self-assessed persistence was not related to BH endurance. This study provides evidence of the stability of BH across time when tested under the same conditions in young adults. Further research is needed to clarify whether BH is linked to behavioral outcomes.
| S-EPMC5591393 | biostudies-literature
Project description:BackgroundDespite considerable progress, it remains unclear why some patients admitted for COVID-19 develop adverse outcomes while others recover spontaneously. Clues may lie with the predisposition to hypoxemia or unexpected absence of dyspnea ('silent hypoxemia') in some patients who later develop respiratory failure. Using a recently-validated breath-holding technique, we sought to test the hypothesis that gas exchange and ventilatory control deficits observed at admission are associated with subsequent adverse COVID-19 outcomes (composite primary outcome: non-invasive ventilatory support, intensive care admission, or death).MethodsPatients with COVID-19 (N = 50) performed breath-holds to obtain measurements reflecting the predisposition to oxygen desaturation (mean desaturation after 20-s) and reduced chemosensitivity to hypoxic-hypercapnia (including maximal breath-hold duration). Associations with the primary composite outcome were modeled adjusting for baseline oxygen saturation, obesity, sex, age, and prior cardiovascular disease. Healthy controls (N = 23) provided a normative comparison.ResultsThe adverse composite outcome (observed in N = 11/50) was associated with breath-holding measures at admission (likelihood ratio test, p = 0.020); specifically, greater mean desaturation (12-fold greater odds of adverse composite outcome with 4% compared with 2% desaturation, p = 0.002) and greater maximal breath-holding duration (2.7-fold greater odds per 10-s increase, p = 0.036). COVID-19 patients who did not develop the adverse composite outcome had similar mean desaturation to healthy controls.ConclusionsBreath-holding offers a novel method to identify patients with high risk of respiratory failure in COVID-19. Greater breath-hold induced desaturation (gas exchange deficit) and greater breath-holding tolerance (ventilatory control deficit) may be independent harbingers of progression to severe disease.
| S-EPMC8200551 | biostudies-literature
Project description:Background:In the view of the epidemic growth of sensitization to indoor allergens in Southern Vietnam, there is a requirement to screen large population. Objective:To evaluate skin prick tests (SPTs) as predictors of positive specific IgE (sIgE) to dust allergens, among patients with chronic respiratory diseases (CRDs). Methods:The sensitization to Blomia tropicalis (Blo t), Dermatophagoides pteronissinus (Der p), and Blattella germanica allergens (Bla g) were evaluated among 610 CRD, both SPT (?4 mm) and sIgE by immuno-CAP (?0.7 kUA/L). Results:Based on sIgE, 45%, 32%, and 33% of patients with CRD were sensitized to Blo t, Der p, and Bla g, respectively, compared to 19%, 18%, and 13% by SPT. The association between SPT and sIgE was statistically significant, though the Kappa factor was fair (i.e., 0.39 to 0.23). While the specificity of SPT to detect sensitization (compared to sIgE) was >90% among the whole population, the sensitivity was only 34%, 41%, and 24% for Bo t, Der p, and Bla g, suggesting that SPT was not enough sensitive to screen the indoor allergen sensitization. Though, among the <10 pack-year (PY) smokers, the sensitivity was 43% for Blo t, 52% for Der p, and 61% for Blo t and/or Der p, compared to 27%, 30%, and 35% among the ?10 PY smokers. The sensitivity/specificity was not associated with the diagnosis of asthma compared to chronic obstructive pulmonary disease. Conclusion:In the present circumstance, SPT to dust mites allergens can be used to detect a sensitization among CRD population in Southern Vietnam.
| S-EPMC6209603 | biostudies-literature
Project description:PurposeDyspnea related to chronic pulmonary disorders is difficult to manage. In this single-arm study, we evaluated feasibility and potential efficacy of a self-care breath training program to reduce dyspnea that persists despite standard treatments in patients with chronic lung disease.MethodsAdult patients with a chronic pulmonary disorder and stable moderate dyspnea received one 30-min training on specific breathing techniques, followed by audio-guided at-home practice 15 min twice daily for 6 wk, supported with weekly telephone monitoring/coaching. The feasibility endpoints, Baseline and Transition Dyspnea Indexes, 6-min walk test, Hospital Anxiety and Depression Scale, and oxygen saturation at rest and exercise were evaluated at baseline and wk 6.ResultsOf the 23 patients enrolled over 2 yr, 19 completed the study. A majority (74%; 95% CI, 49%-91%) completed at least 75% of the home practice sessions. Significant objective improvements in physical performance, defined as distance walked, were observed after 6 wk of intervention. On average, patients walked significantly further in the 6-min walk test (59 ft; 95% CI, 18-99; P = .007). In addition, 53% reported clinically significant (20%, defined a priori) subjective improvement in the Transition Dyspnea Index, although the difference was not statistically significant (0.7; 95% CI, -0.8 to 2.3; P = .3). No significant differences were seen in the Hospital Anxiety and Depression Scale or oxygen saturation.ConclusionsA low-burden, low-cost, self-care breath training program improved distance walked by patients with chronic dyspnea after 6 wk of home practice. Promising data suggest that a randomized trial of this breath training program is warranted.
| S-EPMC6309932 | biostudies-literature
Project description:Stimulation of cerebral vasculature using hypercapnia has been widely used to study cerebral vascular reactivity (CVR), which can be expressed as the quantitative change in cerebral blood flow (CBF) per mm Hg change in end-tidal partial pressure of CO2 (PETCO2). We investigate whether different respiratory manipulations, with arterial spin labeling used to measure CBF, lead to consistent measures of CVR. The approaches included: (1) an automated system delivering variable concentrations of inspired CO2 for prospective targeting of PETCO2, (2) administration of a fixed concentration of CO2 leading to subject-dependent changes in PETCO2, (3) a breath-hold (BH) paradigm with physiologic modeling of CO2 accumulation, and (4) a maneuver combining breath-hold and hyperventilation. When CVR was expressed as the percent change in CBF per mm Hg change in PETCO2, methods 1 to 3 gave consistent results. The CVR values using method 4 were significantly lower. When CVR was expressed in terms of the absolute change in CBF (mL/100 g per minute per mm Hg), greater discrepancies became apparent: methods 2 and 3 gave lower absolute CVR values compared with method 1, and the value obtained with method 4 was dramatically lower. Our findings indicate that care must be taken to ensure that CVR is measured over the linear range of the CBF-CO2 dose-response curve, avoiding hypocapnic conditions.
| S-EPMC3705433 | biostudies-other
Project description:This study evaluated the breathing pattern and distribution of ventilation in horses prior to and following recovery from general anaesthesia using electrical impedance tomography (EIT). Six horses were anaesthetised for 6 hours in dorsal recumbency. Arterial blood gas and EIT measurements were performed 24 hours before (baseline) and 1, 2, 3, 4, 5 and 6 hours after horses stood following anaesthesia. At each time point 4 representative spontaneous breaths were analysed. The percentage of the total breath length during which impedance remained greater than 50% of the maximum inspiratory impedance change (breath holding), the fraction of total tidal ventilation within each of four stacked regions of interest (ROI) (distribution of ventilation) and the filling time and inflation period of seven ROI evenly distributed over the dorso-ventral height of the lungs were calculated. Mixed effects multi-linear regression and linear regression were used and significance was set at p<0.05. All horses demonstrated inspiratory breath holding until 5 hours after standing. No change from baseline was seen for the distribution of ventilation during inspiration. Filling time and inflation period were more rapid and shorter in ventral and slower and longer in most dorsal ROI compared to baseline, respectively. In a mixed effects multi-linear regression, breath holding was significantly correlated with PaCO2 in both the univariate and multivariate regression. Following recovery from anaesthesia, horses showed inspiratory breath holding during which gas redistributed from ventral into dorsal regions of the lungs. This suggests auto-recruitment of lung tissue which would have been dependent and likely atelectic during anaesthesia.
| S-EPMC4917253 | biostudies-literature