Search

Background: The recruitment-to-inflation ratio (R/I) has been recently proposed to bedside assess response to PEEP. The impact of PEEP on ventilator-induced lung injury depends on the extent of dynamic strain reduction. We hypothesized that R/I may reflect the potential for lung recruitment (i.e. recruitability) and, consequently, estimate the impact of PEEP on dynamic lung strain, both assessed through computed tomography scan. Methods: Fourteen lung-damaged pigs (lipopolysaccharide infusion) underwent ventilation at low (5 cmH2O) and high PEEP (i.e., PEEP generating a plateau pressure of 28–30 cmH2O). R/I was measured through a one-breath derecruitment maneuver from high to low PEEP. PEEP-induced changes in dynamic lung strain, difference in nonaerated lung tissue weight (tissue recruitment) and amount of gas entering previously nonaerated lung units (gas recruitment) were assessed through computed tomography scan. Tissue and gas recruitment were normalized to the weight and gas volume of previously ventilated lung areas at low PEEP (normalized-tissue recruitment and normalized-gas recruitment, respectively). Results: Between high (median [interquartile range] 20 cmH2O [18–21]) and low PEEP, median R/I was 1.08 [0.88–1.82], indicating high lung recruitability. Compared to low PEEP, tissue and gas recruitment at high PEEP were 246 g [182–288] and 385 ml [318–668], respectively. R/I was linearly related to normalized-gas recruitment (r = 0.90; [95% CI 0.71 to 0.97) and normalized-tissue recruitment (r = 0.69; [95% CI 0.25 to 0.89]). Dynamic lung strain was 0.37 [0.29–0.44] at high PEEP and 0.59 [0.46–0.80] at low PEEP (p < 0.001). R/I was significantly related to PEEP-induced reduction in dynamic (r = − 0.93; [95% CI − 0.78 to − 0.98]) and global lung strain (r = − 0.57; [95% CI − 0.05 to − 0.84]). No correlation was found between R/I and and PEEP-induced changes in static lung strain (r = 0.34; [95% CI − 0.23 to 0.74]). Conclusions: In a highly recruitable ARDS model, R/I reflects the potential for lung recruitment and well estimates the extent of PEEP-induced reduction in dynamic lung strain. [ABSTRACT FROM AUTHOR]

Objectives Pulmonary arterial hypertension associated with systemic sclerosis (PAH-SSc) sometimes accompanies pulmonary veno-occlusive disease (PVOD). We aimed to reveal the relationship between clinical signs of PVOD and severity of pulmonary vasculopathy in SSc. Methods This study included 52 consecutive SSc patients who had pulmonary haemodynamic abnormalities [mean pulmonary arterial pressure (mPAP) >20 mmHg, pulmonary vascular resistance >2 WU or pulmonary artery wedge pressure (PAWP) >15 mmHg]. A chest CT scan was evaluated in all patients. Patients were divided into two groups, the 0–1 group and the 2–3 group, according to the number of chest CT signs for PVOD, including mediastinal lymph node enlargement, thickened interlobular septal wall and ground glass opacity. Pulmonary haemodynamics, echocardiography and MRI-based cardiac function, pulmonary function and serum biomarkers were compared between the two groups. Results Mediastinal lymph node enlargement, thickened interlobular septal wall and ground glass opacity were observed in 11 (21%), 32 (62%) and 11 (21%) patients, respectively. The 2–3 group (n  = 15) had higher mPAP (P  = 0.02) but lower diffusing capacity of carbon monoxide (DLCO)/alveolar volume (P  = 0.02) compared with the 0–1 group (n  = 37). Other parameters, including PAWP, cardiac output, left ventricular ejection fraction, left atrial diameter, forced vital capacity, brain natriuretic peptide and Krebs von den Lunge-6 were not different between the two groups. Conclusions The CT signs for PVOD had a positive correlation with mPAP but a negative correlation with DLCO in SSc patients, indicating that PAH-SSc may reflect a spectrum of pulmonary vascular disease that ranges from the pulmonary artery to the vein. [ABSTRACT FROM AUTHOR]

Background: Ratio of arterial pressure of oxygen and fraction of inspired oxygen (P/F ratio) together with the fractional dead space (Vd/Vt) provides a global assessment of pulmonary gas exchange. The aim of this study was to assess the potential value of these variables to prognosticate 90‐day survival in patients with COVID‐19 associated ARDS admitted to the Intensive Care Unit (ICU) for invasive ventilatory support. Methods: In this single‐center observational, retrospective study, P/F ratios and Vd/Vt were assessed up to 4 weeks after ICU‐admission. Measurements from the first 2 weeks were used to evaluate the predictive value of P/F ratio and Vd/Vt for 90‐day mortality and reported by the adjusted hazard ratio (HR) and 95% confidence intervals [95%CI] by Cox proportional hazard regression. Results: Almost 20,000 blood gases in 130 patients were analyzed. The overall 90‐day mortality was 30% and using the data from the first ICU week, the HR was 0.85 [0.77–0.94] for every 10 mmHg increase in P/F ratio and 1.61 [1.20–2.16] for every 0.1 increase in Vd/Vt. In the second week, the HR for 90‐day mortality was 0.82 [0.75–0.89] for every 10 mmHg increase in P/F ratio and 1.97 [1.42–2.73] for every 0.1 increase in Vd/Vt. Conclusion: The progressive changes in P/F ratio and Vd/Vt in the first 2 weeks of invasive ventilatory support for COVID‐19 ARDS were significant predictors for 90‐day mortality. [ABSTRACT FROM AUTHOR]

Purpose: To determine in trained females and males i) the agreement between the gas exchange threshold (GET), lactate threshold 1 (LT1), and heart rate variability threshold 1 (HRVT1), as well as between the respiratory compensation point (RCP), lactate threshold 2 (LT2), and heart rate variability threshold 2 (HRVT2), and ii) the reproducibility of HRVT1 and HRVT2 during 2-min incremental step protocols. Methods: Fifty-seven trained participants (24 females) completed a 2-min step incremental test to task failure. Nineteen participants (eight females) completed a second test to evaluate reproducibility. Gas exchange and ventilatory responses, blood lactate concentration, and RR time series were recorded to assess the oxygen consumption (...) and heart rate (HR) associated with the GET, RCP, LT1, LT2, HRVT1, and HRVT2. Results: /-GET versus ...-HRVT1 and HR-GET versus HR-HRVT1 were statistically different for females (29.5 ± 4.0 vs 34.6 ± 6.1 mL⋅kg-1⋅min-1; 154 ± 11 vs 166 ± 12 bpm) and for males (33.9 ± 4.2 vs 42.7 ± 4.6 mL⋅kg-1·min-1; 145 ± 11 vs 165 ± 9 bpm; P < 0.001). ... and HR at HRVT1 were greater than at LT1 (P < 0.05). ...-RCP versus ...-HRVT2 and HR-RCP versus HR-HRVT2 were not statistically different for females (40.1 ± 4.7 vs 39.5 ± 6.7 mL⋅kg-1⋅min-1; 177 ± 9 vs 176 ± 9 bpm) and males (48.4 ± 5.4 vs 47.8 ± 4.8mL⋅kg-1⋅min-1; 176 ± 8 vs 175 ± 9 bpm; P > 0.05). ... and HR responses at LT2 were similar to HRVT2 (P > 0.05). Intraclass correlation coefficient for .-HRVT1, HR-HRVT1, ...-HRVT2, and HR-HRVT2 indicated good reproducibility when comparing the two different time points to standard methods. Conclusions: Whereas HRVT2 is a valid and reproducible estimate of the RCP/LT2, current approaches for HRVT1 estimation did not show good agreement with outcomes at GET and LT1. [ABSTRACT FROM AUTHOR]

Introduction: This study assessed the effect of individualized, domain-based exercise intensity prescription on changes in maximal oxygen uptake (...) and submaximal thresholds. Methods: Eighty-four young healthy participants (42 females, 42males) were randomly assigned to six age, sex, and ...-matched groups (14 participants each). Groups performed continuous cycling in the 1) moderate (MOD), 2) lower heavy (HVY1), and 3) upper heavy-intensity (HVY2) domain; interval cycling in the form of 4) high-intensity interval training (HIIT) in the severe-intensity domain, or 5) sprint-interval training (SIT) in the extreme-intensity domain; or no exercise for 6) control (CON). All training groups, except SIT, were work-matched. Training participants completed three sessions per week for 6 wk with physiological evaluations performed at PRE, MID, and POST intervention. Results: Compared with the change in ... (...) in CON (0.1 ± 1.2 mL⋅kg-1⋅min-1), all training groups, exceptMOD (1.8 ± 2.7 mL⋅kg-1⋅min-1), demonstrated a significant increase ( P < 0.05). HIIT produced the highest increase (6.2 ± 2.8 mL⋅kg-1⋅min-1) followed by HVY2 (5.4 ± 2.3 mL⋅kg-1⋅min-1), SIT (4.7 ± 2.3 mL⋅kg-1⋅min-1), and HVY1 (3.3 ± 2.4 mL⋅kg-1⋅min-1), respectively. The ΔPO at the estimated lactate threshold (θLT) was similar across HVY1, HVY2, HIIT, and SIT, which were all greater than CON (P < 0.05). The ... and ΔPO at θLT for MOD was not different from CON (P > 0.05). HIIT produced the highest ΔPO at maximal metabolic steady state, which was greater than CON, MOD, and SIT (P < 0.05). Conclusions: This study demonstrated that i) exercise intensity is a key component determining changes in ... and submaximal thresholds and ii) exercise intensity domain-based prescription allows for a homogenous metabolic stimulus across individuals. [ABSTRACT FROM AUTHOR]

This study aimed to highlight the ventilatory and circulatory determinants of changes in ˙VO2 peak after exercise-based cardiac rehabilitation (ECR) in patients with coronary heart disease (CHD). Eighty-two CHD patients performed, before and after a 3-month ECR, a cardiopulmonary exercise testing (CPET) on a bike with gas exchanges measurements (˙VO2 peak, minute ventilation, i. e., ˙VE), and cardiac output (Q˙c). The arteriovenous difference in O2 (C(a-v¯)O2) and the alveolar capillary gradient in O2 (PAi-aO2) were calculated using Fick's laws. Oxygen uptake efficiency slope (OUES) was calculated. A 5.0% cut off was applied for differentiating non- (NR: ˙VO2 <0.0%), low (LR: 0.0≤ ∆˙VO2 <5.0%), moderate (MR: 5.0≤∆˙VO2 < 10.0%), and high responders (HR: ∆˙VO2 ≥10.0%) to ECR. A total of 44% of patients were HR (n=36), 20% MR (n=16), 23% LR (n=19), and 13% NR (n=11). For HR, the ˙VO2 peak increase (p<0.01) was associated with increases in ˙VE (+12.8±13.0 L/min, p<0.01), (+1.0±0.9 L/min, p<0.01), and C(a-v¯)O2 (+2.3±2.5 mLO2 /100 mL, p<0.01). MR patients were characterized by+6.7±19.7 L/min increase in ˙VE (p=0.04) and+0.7±1.0 L/min of Q˙c (p<0.01). ECR induced decreases in ˙VE (p=0.04) and C(a-v¯)O2 (p<0.01) and a Q˙c increase in LR and NR patients (p<0.01). Peripheral and ventilatory responses more than central adaptations could be responsible for the ˙VO2 peak change with ECR in CHD patients. [ABSTRACT FROM AUTHOR]

The maximum oxygen uptake (VO2max) is a critical factor for endurance performance in soccer. Novel wearable technology may allow frequent assessment of VO2max during non-fatiguing warm-up runs of soccer players with minimal interference to soccer practice. The aim of this study was to assess the validity of VO2max provided by a consumer grade smartwatch (Garmin Forerunner 245, Garmin, Olathe, USA, Software:13.00) and the YoYo Intermittent Recovery Run 2 (YYIR2) by comparing it with respiratory gas analysis. 24 trained male youth soccer players performed different tests to assess VO2max: i) a treadmill test employing respiratory gas analysis, ii) YYIR2 and iii) during a non-fatiguing warm-up run of 10 min wearing a smartwatch as recommended by the device-manufacturer on 3 different days within 2 weeks. As the device-manufacturer indicates that validity of smartwatch-derived VO2max may differ with an increase in runs, 16 players performed a second run with the smartwatch to test this claim. The main evidence revealed that the smartwatch showed an ICC of 0.37 [95% CI: -0.25; 0.71] a mean absolute percentage error (MAPE) of 5.58% after one run, as well as an ICC of 0.54 [95% CI: -0.3; 8.4] and a MAPE of 1.06% after the second run with the smartwatch. The YYIR2 showed an ICC of 0.17 [95% CI: -5.7; 0.6]; and MAPE of 4.2%. When using the smartwatch for VO2max assessment in a non-fatiguing run as a warm-up, as suggested by the device manufacturer before soccer practice, the MAPE diminishes after two runs. Therefore, for more accurate VO2max assessment with the smartwatch, we recommend to perform at least two runs to reduce the MAPE and enhance the validity of the findings. [ABSTRACT FROM AUTHOR]

Objectives Autologous hematopoietic stem cell transplantation (AHSCT) has been shown to improve long-term survival for early diffuse progressive SSc compared with CYC. CYC, however, does not provide a long-term benefit in SSc. The combination of MMF and rituximab is a potent alternative regimen. We aimed to retrospectively compare the outcomes of SSc patients who underwent AHSCT to patients who met the eligibility criteria for AHSCT but received upfront combination therapy with MMF and rituximab. Methods Repeated assessments of modified Rodnan Skin Score (mRSS), forced vital capacity (FVC), and diffusing capacity (DLCO) values were conducted. Clinical improvement was defined as an mRSS decrease >25% or an FVC increase >10%. Event-free survival (EFS) was defined in the absence of persistent major organ failure or death. Results Twenty-one SSc patients in the combination therapy group were compared with 16 in the AHSCT group. Age, sex and disease duration were similar between the two groups. Clinical improvement at 12 months was seen in 18 (86%) patients in the combination group compared with 13 (81%) in the AHSCT group (P  = 0.7). The hazard ratio for EFS at 24 months favoured the combination group (HR = 0.09, P  = 0.04). During follow-up, both groups exhibited a significant and comparable reduction in mRSS and an increase in FVC values at each time interval up to 24 months. Conclusion MMF and rituximab compared with AHSCT in SSc patients eligible for AHSCT resulted in similar skin and lung clinical improvement with a better safety profile at 24 months. [ABSTRACT FROM AUTHOR]

Blood flow restriction (BFR) is increasingly being used to enhance aerobic performance in endurance athletes. This study examined physiological responses to BFR applied in recovery phases within a high‐intensity interval training (HIIT) session in trained cyclists. Eleven competitive road cyclists (mean ± SD, age: 28 ± 7 years, body mass: 69 ± 6 kg, peak oxygen uptake: 65 ± 9 mL · kg−1 · min−1) completed two randomised crossover conditions: HIIT with (BFR) and without (CON) BFR applied during recovery phases. HIIT consisted of six 30‐s cycling bouts at an intensity equivalent to 85% of maximal 30‐s power (523 ± 93 W), interspersed with 4.5‐min recovery. BFR (200 mmHg, 12 cm cuff width) was applied for 2‐min in the early recovery phase between each interval. Pulmonary gas exchange (V̇O2, V̇CO2, and V̇E), tissue oxygen saturation index (TSI), heart rate (HR), and serum vascular endothelial growth factor concentration (VEGF) were measured. Compared to CON, BFR increased V̇CO2 and V̇E during work bouts (both p < 0.05, dz < 0.5), but there was no effect on V̇O2, TSI, or HR (p > 0.05). In early recovery, BFR decreased TSI, V̇O2, V̇CO2, and V̇E (all p < 0.05, dz > 0.8) versus CON, with no change in HR (p > 0.05). In late recovery, when BFR was released, V̇O2, V̇CO2, V̇E, and HR increased, but TSI decreased versus CON (all p < 0.05, dz > 0.8). There was a greater increase in VEGF at 3‐h post‐exercise in BFR compared to CON (p < 0.05, dz > 0.8). Incorporating BFR into HIIT recovery phases altered physiological responses compared to exercise alone. Highlights: Blood flow restriction (BFR) during high‐intensity interval training recovery phases increased acute physiological perturbations and angiogenic markers compared to interval training alone.During the early recovery phases of high‐intensity interval cycling, BFR decreased muscle oxygenation, V̇O2, V̇CO2, and V̇E compared to CON condition with unrestricted recovery. [ABSTRACT FROM AUTHOR]

Introduction: Exacerbations are common in individuals with alpha-1 antitrypsin deficiency (AATD)-related lung disease. This study intended to identify independent predictive factors for exacerbations in AATD using the Portuguese European Alpha-1 Research Collaboration (EARCO) registry. Methods: This study includes patients from the Portuguese EARCO registry, a prospective multicenter cohort (NCT04180319). From October 2020 to April 2023, this registry enrolled 137 patients, 14 of whom were excluded for analysis for either missing 12 months of follow-up or baseline pulmonary function. Results: Among the 123 AATD patients, 27 (22.0%) had at least one exacerbation in the last 12 months of follow-up. Patients with Pi*ZZ phenotype were three times more likely than the rest of the population to experience any exacerbation (32.7 vs. 14.1%, p = 0.014; OR 3.0). BODE index was significantly higher in exacerbators than in non-exacerbators (3.9 ± 2.4 vs. 1.3 ± 1.2; p < 0.001), including on multivariate analysis (p = 0.002). Similar results were found for BODEx (multivariate p < 0.001). DLCO was the only functional parameter independently associated with exacerbations (p = 0.024). Conclusions: DLCO, BODE, and BODEx were independent predictors of exacerbations at 12 months in AATD patients. Understanding these risk factors can aid decision-making on AATD-related lung disease management and improve patient outcomes. [ABSTRACT FROM AUTHOR]

Objective: High-resolution computed tomography (HRCT) may lack sensitivity for the early detection of interstitial lung disease associated with systemic sclerosis (SSc-ILD). Lung ultrasound is an emerging technique for the diagnosis of SSc-ILD. This cross-sectional study aimed to describe the prevalence of ultrasound interstitial syndrome in SSc patients with normal HRCT and pulmonary function tests (PFT). Methods: Thirty SSc patients with normal HRCT, FVC > 80% predicted and DLCO > 70% predicted were included. Echocardiography and PFT including impulse oscillometry and cardiopulmonary exercise testing were performed. Lung ultrasound was analyzed by two blinded operators. Patients were classified into two groups, according to the presence or absence of ultrasound interstitial syndrome, defined as the sum of B-lines in all thoracic areas ≥10 and/or pleural line thickness >3 mm on at least one thoracic area and/or a pleural line irregularity score >16%. Results: Ultrasound interstitial syndrome was present in 12 patients (40%). Inter-reader agreement for the diagnosis of ultrasound interstitial syndrome defined by the Kappa coefficient was 0.93 (95%CI 0.79–1.00). Patients with ultrasound interstitial syndrome were younger (37 years vs. 53 years, p = 0.009), more often had pitting scars (n = 7/12 vs. 3/18, p = 0.045) and had lower FVC (102 vs. 110% pred, p = 0.009), TLC (114 vs. 122% pred, p = 0.042) and low-frequency respiratory system reactance (Xrs5 Z-score 0.16 vs. 1.02, p = 0.018), while pulmonary gas exchange was similar. Conclusions: Ultrasound interstitial syndrome was detected in 12/30 SSc patients with normal HRCT and PFT. Patients with ultrasound interstitial syndrome had differences in lung function consistent with reduced respiratory compliance, suggesting minimal and/or early suspected SSc-ILD. [ABSTRACT FROM AUTHOR]

During prolonged running at moderate‐to‐high intensity, running economy (RE) deteriorates and attainable maximal oxygen consumption (VO2max) decreases. Whether these changes appear similarly in trained and untrained runners exercising at the same relative intensity is not clear. We recruited 10 trained runners (TR) and 10 active adults (AA), and compared RE and attainable VO2max before and after 1 h of running at 70% of VO2max. Submaximal VO2 increased more (p = 0.019) in AA (0.20 ± 0.13 L min−1) than in TR (0.07 ± 0.05 L min−1). Attainable VO2max decreased in AA (−0.21 ± 0.15 L min−1, p = 0.002), but remained unchanged in TR (−0.05 ± 0.10 L min−1, p = 0.18). Relative intensity (i.e., VO2/attainable VO2max), increased more (p = 0.001) in AA (8.3 ± 4.4%) than in TR (2.6 ± 1.9%). These results demonstrate that the ability to resist changes in RE and VO2max following prolonged running is superior in trained versus untrained runners, when exercising at the same relative intensity. [ABSTRACT FROM AUTHOR]

Purpose: Heart rate (HR) is a widespread method to estimate oxygen consumption ( V ˙ O2), exercise intensity, volume, and energy expenditure. Still, accuracy depends on lab tests or using indexes like HRnet and HRindex. This study addresses HR indexes' applicability in postmenopausal women (PMW), who constitute over 50% of the aging population and may have unique characteristics (e.g., heart size) affecting HR use. Methods: Fourteen PMW underwent a cycling ramp incremental test to establish the relationships between V ˙ O2 (in MET) and absolute HR, HRnet, and HRindex. In a second group of ten PMW, population-specific and general equations were tested to predict MET and energy expenditure during six constant work exercises at various intensities. Pulmonary gas exchange and HR were continuously measured using a metabolic cart. Correlations, Bland–Altman analysis, and two-way RM-ANOVA were used to compare estimated and measured values. Results: Strong linear relationships between the three HR indexes and MET were found in Group 1. In Group 2, population-specific equations showed medium-to-high correlations, precision, and no significant biases when estimating MET and energy expenditure. HRnet and HRindex outperformed absolute HR in accuracy. General HR equations had similar correlations but exhibited larger biases and imprecision. Statistical differences between measured and estimated values were observed at all intensities with general equations. Conclusion: This investigation confirms the suitability of HR for estimating aerobic metabolism in one of the most significant aging populations. However, it emphasizes the importance of considering individual variability and developing population-specific models when utilizing HR to infer metabolism. [ABSTRACT FROM AUTHOR]

The step-ramp-step (SRS) can assign constant-load exercise intensities from a ramp-incremental test. Its precision using different moderate-intensity (MOD) steps or ramp slopes has yet to be evaluated. Purpose: To assess whether: i) a lower amplitude constant-load MOD is appropriate to determine the mean response time (MRT); ii) the method accurately corrects the dissociation in the ...O2-PO relationship during ramp compared with constant-load exercise when using different ramp slopes. Methods: Eighteen participants (7 females) performed three SRS tests including: i) step-transitions into MOD from 20 to 50 W (MOD50) and 80 W (MOD80); and ii) slopes of 15, 30, and 45 W⋅min-1. The ...O2 and PO at the gas exchange threshold (GET) and the corrected respiratory compensation point (RCPCORR) were determined. Two to three 30-min constant-load trials evaluated the ...O2 and PO at the maximal metabolic steady state (MMSS). Results: There were no differences in ...O2 at GET (1.97 ±0.36,1.99 ±0.36, 1.95 ±0.30 L⋅min-1), andRCP (2.81 ±0.57,2.86± 0.59,2.84 ±0.59) between 15,30, and 45 W⋅min-1 ramps, respectively (P >0.05). The MRT in seconds was not affected by the amplitude of the MOD or the slope of the ramp (range 19 ± 10 s to 23 ± 20 s; P > 0.05). The mean PO at GET was not significantly affected by the amplitude of the MOD or the slope of the ramp (range 130 ± 30 W to 137 ± 30 W; P > 0.05). The PO at RCPCORR was similar for all conditions ((range 186 ± 43 W to 193 ± 47 W; P > 0.05). Conclusions: The SRS protocol accounts for the ...O2 MRT when using smaller amplitude steps, and for the ...O2 slow component when using different ramp slopes, allowing for accurate partitioning of the exercise intensity domains in a single test. [ABSTRACT FROM AUTHOR]

The success of immediate adaptation to extrauterine life depends on appropriate lung function, however, elective cesarean section can increase the risk of respiratory distress as a result of reduced pulmonary fluid absorption. This study aimed to evaluate the influence of birth mode on pulmonary clearance and respiratory performance of canine neonates in the transition period. For this purpose, 37 neonates were selected according to the obstetric condition: Vaginal Eutocia (n = 17) and Elective C-section (n = 20). Neonates were evaluated for neonatal vitality score, as well as evaluation of heart and respiratory rates, body temperature and body weight, venous hemogasometric evaluation, blood lactate and glucose, pulse oximetry and radiographic evaluation during the first 24 h of life. Additionally, amniotic fluid electrolyte composition of each puppy was evaluated. There was no influence of the type of delivery on electrolyte composition of canine amniotic fluid and neonatal pulmonary liquid content, analyzed by thoracic X-Rays. On the other hand, elective cesarean section delayed pulmonary adaptation, resulting in hypoxemia and less efficient compensatory response to acid-base imbalance and thermoregulation. In conclusion, elective c-section does not delay pulmonary clearance, whilst alters pulmonary adaptation by less efficient gas exchange and lower oxygenation, hindering the compensatory response to acid-base imbalance during the fetal-neonatal transition in dogs. • Elective c-section does not modify radiographic pulmonary content in puppies. • Elective c-section delays clinical pulmonary stabilization after birth in puppies. • Elective c-section hinders the compensatory response to acid-base imbalance. • Elective c-section delays pulmonary efficient gas exchange in puppies. [ABSTRACT FROM AUTHOR]

Introduction: Bronchoscopic lung volume reduction (BLVR) with endobronchial valves has been shown to be a safe and effective treatment for patients with severe lung emphysema. Previous studies have reported a benefit in pulmonary function, exercise capacity, and quality of life after BLVR-treatment. The effect of BLVR with valves on the pulmonary gas exchange and its association with clinical outcomes has not been analyzed to date. The primary goal of this study was to investigate the impact of BLVR on the pulmonary gas exchange and the impact of the target lobe selection in patients with discordant target lobes in high-resolution computed tomography (HRCT) scan and perfusion scan on the pulmonary gas exchange and clinical outcomes. Methods: In this single-center study, we retrospectively analyzed pulmonary function tests, 6-min-walk-tests, HRCT scans, perfusion scans, and blood gas analyses in 77 patients over the course of 6 months following BLVR treatment. Results: We observed that complete lobar occlusion with bronchoscopic valves leads to a transient impairment of pulmonary gas exchange. Despite this, an overall positive clinical outcome could be shown in patients treated with endobronchial valves. If the target lobe selection based on HRCT and perfusion scans is discrepant, a selection based on the HRCT scan tends to be associated with a better outcome than a selection based on the perfusion scan. Conclusions: Complete lobar occlusion with bronchoscopic valves leads to a transient impairment of pulmonary gas exchange but nevertheless results in an overall positive clinical outcome. [ABSTRACT FROM AUTHOR]

During veno-venous extracorporeal membrane oxygenation (V-V ECMO), blood is drained from the central venous circulation to be oxygenated and decarbonated by an artificial lung. It is then reinfused into the right heart and pulmonary circulation where further gas-exchange occurs. Each of these steps is characterized by a peculiar physiology that this manuscript analyses, with the aim of providing bedside tools for clinical care: we begin by describing the factors that affect the efficiency of blood drainage, such as patient and cannulae position, fluid status, cardiac output and ventilatory strategies. We then dig into the complexity of extracorporeal gas-exchange, with particular reference to the effects of extracorporeal blood-flow (ECBF), fraction of delivered oxygen (FdO2) and sweep gas-flow (SGF) on oxygenation and decarbonation. Subsequently, we focus on the reinfusion of arterialized blood into the right heart, highlighting the effects on recirculation and, more importantly, on right ventricular function. The importance and challenges of haemodynamic monitoring during V-V ECMO are also analysed. Finally, we detail the interdependence between extracorporeal circulation, native lung function and mechanical ventilation in providing adequate arterial blood gases while allowing lung rest. In the absence of evidence-based strategies to care for this particular group of patients, clinical practice is underpinned by a sound knowledge of the intricate physiology of V-V ECMO. [ABSTRACT FROM AUTHOR]

Basketball is a dynamic sport, requiring athletes to elicit a high-level of physical, tactical, technical, and psychological attributes and athletes must possess a robustly trained aerobic energy system. There is no research to assess how objectively measured training loads throughout a season influence aerobic capacity. The following study was a retrospective analysis of an NCAA Division I women's basketball team throughout a 5-month (23-week) competitive season. Data were sorted into season half totals and maximal oxygen consumption was recorded before, at the midway point and within 1-week postseason. Twelve athletes were monitored during each practice, pregame shoot around, scrimmage, and game for a total of 1,378 recorded sessions with a valid heart rate-based wearable microsensor (Polar Team Pro) during the season. There was a main effect of time for ...O2max throughout the season (p < 0.001). Post hoc analysis revealed there was a significant increase in ...O2max from preseason to postseason (p < 0.001). Interestingly, there were significant (p ≤ 0.001 for all) decreases from the first half to the second half of the season for training load, and time allocated to HRZone1-4, but no difference in time for the most intense zone, HRzone5. Conclusion: Oxygen consumption significantly increased 7.5% from preseason to postseason despite a reduction in overall work. The only training intensity that was not different from the first half to second half of the season was time in the highest heart rate intensity zone ≥85% of HRmax. [ABSTRACT FROM AUTHOR]

Concerns are repeatedly raised about possible adverse respiratory effects of wearing filtering face pieces (FFP) during physical activity. This study compared the impact of FFP type 2 (NF95) on pulmonary function, blood gas values, metabolism and discomfort during light, moderate and vigorous physical activity. Healthy adults (n = 13; 6 females, 7 males; mean 31.3, SD 5.5 years) participated in this randomized two-armed (Ergometer cycling with a FFP type 2 vs. no mask) crossover trial. Baseline cardiopulmonary exercise testing and two interventions (masked and unmasked ergometer cycling 40%, 50% and 70% VO2max, 10 min each) were separated by 48 h washout periods. Spiroergometric data (End tidal carbon dioxide partial pressure PetCO2; breathing frequency; inspiration time), blood gas analysis outcomes (capillary carbon dioxide partial pressure, pCO2) and subjective response (Breathing effort and perceived exertion) were contrasted between conditions using ANOVAs. All participants completed the crossover trial, seven started with the FFP2 condition (No adverse events or side effects). FFP2 decreased breathing frequency, prolonged inspiration time, increased perceived breathing effort and PetCO2 (p <.05). Blood pCO2 in millimetres mercury increased during exercise with 50%VO2max (mean 36.67, SD 3.19 vs. mean 38.46, SD 2.57; p <.05) and 70%VO2max (35.04, 2.84 vs. 38.17, 3.43; p <.05) but not during exercise with 40%VO2max (36.55, 2.73 vs. 38.70). Perceived exertion was not affected (p > 0.05) by mask wearing. Conclusion: Mask-induced breathing resistance decreased respiratory performance and limited pulmonary gas exchange. While FFP2 affected subjective breathing effort per se, invasive diagnostics showed that statistically significant metabolic effects are induced from moderate intensity upwards. Trial registration: DRKS-ID: DRKS00030181, Date of registration: 05/09/2022 (German Register for Clinical Trials). [ABSTRACT FROM AUTHOR]

Background: Postoperative respiratory failure is the most frequent complication in postsurgical patients. The purpose of this study is to assess whether pulmonary function testing in high-risk patients during preoperative assessment detects previously unknown respiratory impairments which may influence patient outcomes. Methods: A targeted patient screening by spirometry and the measurement of the diffusing capacity of the lung for carbon monoxide (DLCO) was implemented in the anesthesia department of a tertiary university hospital. Patients of all surgical disciplines who were at least 75 years old or exhibited reduced exercise tolerance with the metabolic equivalent of task less than four (MET < 4) were examined. Clinical characteristics, history of lung diseases, and smoking status were also recorded. The statistical analysis entailed t-tests, one-way ANOVA, and multiple linear regression with backward elimination for group comparisons. Results: Among 256 included patients, 230 fulfilled the test quality criteria. Eighty-one (35.2%) patients presented obstructive ventilatory disorders, out of which 65 were previously unknown. 38 of the newly diagnosed obstructive disorders were mild, 18 moderate, and 9 severe. One hundred forty-five DLCO measurements revealed 40 (27.6%) previously unknown gas exchange impairments; 21 were mild, 17 moderate, and 2 severe. The pulmonary function parameters of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and DLCO were significantly lower than the international reference values of a healthy population. Patients with a lower ASA class and no history of smoking exhibited higher FVC, FEV1, and DLCO values. Reduced exercise tolerance with MET < 4 was strongly associated with lower spirometry values. Conclusions: Our screening program detected a relevant number of patients with previously unknown obstructive ventilatory disorders and impaired pulmonary gas exchange. This newly discovered sickness is associated with low metabolic equivalents and may influence perioperative outcomes. Whether optimized management of patients with previously unknown impaired lung function leads to a better outcome should be evaluated in multicenter studies. Trial registration: German Registry of Clinical Studies (DRKS00029337), registered on: June 22nd, 2022. [ABSTRACT FROM AUTHOR]

The article focuses on evaluating the performance of metabolic carts, MetaLyzer 3B and Oxycon Pro, for cardiopulmonary exercise testing under different climatic conditions. Topics discussed include the comparison of these carts, their accuracy and reliability, and their suitability for use in various environmental settings.

Introduction: Acetazolamide (AZA) improves nocturnal and daytime blood oxygenation in patients with pulmonary vascular disease (PVD), defined as pulmonary arterial and distal chronic thromboembolic pulmonary hypertension (CTEPH), and may improve exercise performance. Methods: We investigated the effect of 5 weeks of AZA (250 mg bid) versus placebo on maximal load during incremental cycling ramp exercise in patients with PVD studied in a randomized controlled, double-blind, crossover design, separated by > 2 weeks of washout. Results: Twenty-five patients (12 pulmonary arterial hypertension, 13 CTEPH, 40% women, age 62 ± 15 years) completed the trial according to the protocol. Maximum load was similar after 5 weeks of AZA versus placebo (113 ± 9 vs. 117 ± 9 watts [W]), mean difference −4 W (95% CI: −9 to 1, p = 0.138). With AZA, maximum (max)-exercise partial pressure of O2 (PaO2) was significantly higher by 1.1 kPa (95% CI: 0.5–1.8, p = 0.003), while arterial pH and partial pressure of CO2 were significantly lower. Gas exchange threshold was reached at a higher load with AZA (108 ± 8 W vs. 97 ± 8 W) and was therefore delayed by 11 W (95% CI: 3–19, p = 0.013), while the ventilatory equivalent for O2 and CO2 were significantly higher at both the max-exercise and gas exchange threshold with AZA versus placebo. Conclusion: AZA for 5 weeks did not significantly change maximum exercise capacity in patients with PVD despite a significant increase in PaO2. The beneficial effects of increased blood oxygenation may have been diminished by increased ventilation due to AZA-induced metabolic acidosis and increased dyspnea. [ABSTRACT FROM AUTHOR]

Adipose-derived stem cells (ADSCs) are well-recognized for their remarkable ability to suppress ischemia-reperfusion lung injury (IRLI). The primary objective of this investigation was to elucidate the underlying mechanism through which ADSCs exert protective effects against IRLI. A warm hilar occlusion model in C57BL6J mice was used. Hilar occlusion was achieved for 1 hour (ischemic), and after 1 hour the occlusion was released (reperfusion) to recover for 3 hours. RNA sequencing, the physiological function, pathway activation, and expression of inflammatory cytokines were evaluated. Lung gas exchange and pulmonary edema were significantly improved in the IRLI/ADSCs group compared with the IRLI group. RNA sequencing results suggested that the peroxisome proliferator-activated receptor gamma (PPARγ)/nuclear factor-kappa B (NF-κB) pathway was involved in the effect of the ADSCs. Administration of a PPARγ antagonist in the IRLI/ADSC group resulted in the deterioration of the physiological function. Furthermore, the PPARγ protein expression level decreased, the NF-κB protein expression level increased, and inflammatory cytokine parameters from lung tissue and blood sample worsened in the PPARγ antagonist-administered group. Administration of ADSCs exerted a significant protective effect against IRLI in mice, and the effect is attributed to the activation of the PPARγ/NF-κB pathway. [ABSTRACT FROM AUTHOR]

Background: Currently, there are no reliable clinical tools that allow non-invasive therapeutic support for patients with pulmonary arterial hypertension. This study aims to propose a low-frequency ultrasound device for pulmonary hypertension therapy and to demonstrate its potential. Methods: A novel low-frequency ultrasound transducer has been developed. Due to its structural properties, it is excited by higher vibrational modes, which generate a signal capable of deeply penetrating biological tissues. A methodology for the artificial induction of pulmonary hypertension in sheep and for the assessment of lung physiological parameters such as blood oxygen concentration, pulse rate, and pulmonary blood pressure has been proposed. Results: The results showed that exposure of the lungs to low-frequency ultrasound changed physiological parameters such as blood oxygen concentration, pulse rate and blood pressure. These parameters are most closely related to indicators of pulmonary hypertension (PH). The ultrasound exposure increased blood oxygen concentration over a 7-min period, while pulse rate and pulmonary blood pressure decreased over the same period. In anaesthetised sheep exposed to low-frequency ultrasound, a 10% increase in SpO2, a 10% decrease in pulse rate and an approximate 13% decrease in blood pressure were observed within 7 min. Conclusions: The research findings demonstrate the therapeutic efficiency of low-frequency ultrasound on hypertensive lungs, while also revealing insights into the physiological aspects of gas exchange within the pulmonary system. [ABSTRACT FROM AUTHOR]

Purpose: The kinetics of physiological responses to exercise have traditionally been characterized by estimating exponential equation parameters using iterative best-fit techniques of heart rate (HR) and gas exchange (respiratory rate, oxygen uptake (V̇O2), carbon dioxide output, and ventilation). In this study, we present a novel approach to characterizing the maturation of physiological responses to exercise in children by accounting for response uncertainty and variability. Methods: Thirty-seven early-pubertal (17 females, 20 males) and 44 late-pubertal (25 females, 19 males) participants performed three multiple brief exercise bouts (MBEB). MBEB consisted of ten 2-min bouts of cycle ergometry at constant work rate interspersed by 1-min rest. Exercise intensity was categorized as low, moderate, or high, corresponding to 40%, 60%, and 80% of peak work rate, and performed in random order on 3 separate days. We evaluated sample entropy (SampEn), approximate entropy, detrended fluctuation analysis, and average absolute local variability of HR and gas exchange. Results: SampEn of HR and gas-exchange responses to MBEB was greater in early- compared with late-pubertal participants (e.g., V̇O2 early-pubertal vs late-pubertal, 1.70 ± 0.023 vs 1.41 ± 0.027; P = 2.97 × 10−14), and decreased as MBEB intensity increased (e.g., 0.37 ± 0.01 HR for low-intensity compared with 0.21 ± 0.014 for high intensity, P = 3.56 × 10−17). Females tended to have higher SampEn than males (e.g., 1.61 ± 0.025 V̇O2 for females vs 1.46 ± 0.031 for males, P = 1.28 × 10−4). Average absolute local variability was higher in younger participants for both gas exchange and HR (e.g., early-pubertal vs late-pubertal V̇O2, 17.48 % ± 0.56% vs 10.24 % ± 0.34%; P = 1.18 × 10−21). Conclusions: The greater entropy in signal response to a known, quantifiable exercise perturbation in the younger children might represent maturation-dependent, enhanced competition among physiological controlling mechanisms that originate at the autonomic, subconscious, and cognitive levels. [ABSTRACT FROM AUTHOR]

This single-blind, crossover study aimed to measure and evaluate the short-term metabolic responses to continuous and intermittent hypoxic patterns in individuals with obesity. Indirect calorimetry was used to quantify changes in resting metabolic rate (RMR), carbohydrate (CHOox, %CHO), and fat oxidation (FATox, %FAT) in nine individuals with obesity pre and post: 1) breathing normoxic air [normoxic sham control (NS-control)], 2) breathing continuous hypoxia (CH), or 3) breathing intermittent hypoxia (IH). A mean peripheral oxygen saturation (SpO2) of 80-85% was achieved over a total of 45 min of hypoxia. Throughout each intervention, pulmonary gas exchanges, oxygen consumption (V_O2) carbon dioxide production (V_ CO2), and deoxyhemoglobin concentration (D[HHb]) in the vastus lateralis were measured. Both RMR and CHOox measured pre- and postinterventions were unchanged following each treatment: NS-control, CH, or IH (all P > 0.05). Conversely, a significant increase in FATox was evident between pre- and post-IH (þ44%, P = 0.048). Although the mean D[HHb] values significantly increased during both IH and CH (P < 0.05), the greatest zenith of D[HHb] was achieved in IH compared with CH (P = 0.002). Furthermore, there was a positive correlation between D[HHb] and the shift in FATox measured pre- and postintervention. It is suggested that during IH, the increased bouts of muscle hypoxia, revealed by elevated D[HHb], coupled with cyclic periods of excess posthypoxia oxygen consumption (EPHOC, inherent to the intermittent pattern) played a significant role in driving the increase in FATox post-IH. [ABSTRACT FROM AUTHOR]

Sex differences in the cardiorespiratory and hemodynamic response to exercise exist due to differences in heart size, blood volume, and hemoglobin mass, eliciting higher maximal oxygen uptake (VO2max) in men versus women. Data are equivocal whether sex differences in training responsiveness occur. This study investigated potential sex differences in the hemodynamic response (stroke volume (SV) and cardiac output (CO)) to high‐intensity interval exercise (HIIE). Habitually active men (n = 15) and women (n = 13) underwent VO2max testing, followed by three HIIE sessions consisting of the 4 × 4, 10 × 1, and reduced exertion high‐intensity training (REHIT), whose order was randomized. During exercise, oxygen uptake (VO2) and hemodynamic responses were determined. Results showed no sex difference in peak relative VO2 (p = 0.263), CO (p = 0.277), or SV (p = 0.116), although absolute values were higher in men (p < 0.05). Peak absolute (127.3 ± 20.6 vs. 115.2 ± 16.6 mL/beat, p = 0.004, d = 0.66) and relative SV (111.0 ± 15.5 vs. 100.7 ± 11.1% max, p = 0.005, d = 0.78) were higher with REHIT versus 4 × 4. No sex differences in mean relative VO2, CO, or SV occurred (p > 0.05). Data showed lower mean VO2 during REHIT versus 4 × 4 (59.3 ± 6.8 vs. 65.8 ± 5.8 %VO2max, p < 0.001, d = 1.05) and 10 × 1 (59.3 ± 6.8 vs. 69.1 ± 7.4 %VO2max, p < 0.001, d = 1.4). Mean CO was lower in REHIT than 10 × 1 (79.8 ± 8.6 vs. 84.0 ± 7.4% max, p = 0.012, d = 0.53). Previously reported differences in VO2max response to HIIE may not be due to unique hemodynamic responses. [ABSTRACT FROM AUTHOR]

Purpose: Various systems are available for cardiopulmonary exercise testing (CPET), but their accuracy remains largely unexplored. We evaluate the accuracy of 15 popular CPET systems to assess respiratory variables, substrate use, and energy expenditure during simulated exercise. Cross‐comparisons were also performed during human cycling experiments (i.e., verification of simulation findings), and between‐session reliability was assessed for a subset of systems. Methods: A metabolic simulator was used to simulate breath‐by‐breath gas exchange, and the values measured by each system (minute ventilation [V̇E], breathing frequency [BF], oxygen uptake [V̇O2], carbon dioxide production [V̇CO2], respiratory exchange ratio [RER], energy from carbs and fats, and total energy expenditure) were compared to the simulated values to assess the accuracy. The following manufacturers (system) were assessed: COSMED (Quark CPET, K5), Cortex (MetaLyzer 3B, MetaMax 3B), Vyaire (Vyntus CPX, Oxycon Pro), Maastricht Instruments (Omnical), MGC Diagnostics (Ergocard Clinical, Ergocard Pro, Ultima), Ganshorn/Schiller (PowerCube Ergo), Geratherm (Ergostik), VO2master (VO2masterPro), PNOĒ (PNOĒ), and Calibre Biometrics (Calibre). Results: Absolute percentage errors during the simulations ranged from 1.15%–44.3% for V̇E, 1.05–3.79% for BF, 1.10%–13.3% for V̇O2, 1.07%–18.3% for V̇CO2, 0.62%–14.8% for RER, 5.52%–99.0% for Kcal from carbs, 5.13%–133% for Kcal from fats, and 0.59%–12.1% for total energy expenditure. Between‐session variation ranged from 0.86%–21.0% for V̇O2 and 1.14%–20.2% for V̇CO2, respectively. Conclusion: The error of respiratory gas variables, substrate, and energy use differed substantially between systems, with only a few systems demonstrating a consistent acceptable error. We extensively discuss the implications of our findings for clinicians, researchers and other CPET users. [ABSTRACT FROM AUTHOR]

Interstitial lung diseases (ILDs) are a heterogeneous group of pulmonary disorders characterized by variable degrees of inflammation, interstitial thickening, and fibrosis leading to distortion of the pulmonary architecture and gas exchange impairment. Among them, idiopathic pulmonary fibrosis (IPF) displays the worst prognosis. The only therapeutic options consist of the two antifibrotic drugs, pirfenidone and nintedanib, which limit fibrosis progression but do not reverse the lung damage. The shift of the pathogenetic paradigm from inflammatory disease to epithelium-derived disease has definitively established the primary role of type II alveolar cells, which lose their epithelial phenotype and acquire a mesenchymal phenotype with production of collagen and extracellular matrix (EMC) deposition. Some predisposing environmental and genetic factors (e.g., smoke, pollution, gastroesophageal reflux, variants of telomere and surfactant genes) leading to accelerated senescence set a pro-fibrogentic microenvironment and contribute to the loss of regenerative properties of type II epithelial cells in response to pathogenic noxae. This review provides a complete overview of the different pathogenetic mechanisms leading to the development of IPF. Then, we summarize the currently approved therapies and the main clinical trials ongoing. Finally, we explore the potentialities offered by agents not only interfering with the processes of fibrosis but also restoring the physiological properties of alveolar regeneration, with a particular focus on potentialities and concerns about cell therapies based on mesenchymal stem cells (MSCs), whose anti-inflammatory and immunomodulant properties have been exploited in other fibrotic diseases, such as graft versus host disease (GVHD) and COVID-19-related ARDS. [ABSTRACT FROM AUTHOR]

Monitoring the patient receiving veno-venous extracorporeal membrane oxygenation (VV ECMO) is challenging due to the complex physiological interplay between native and membrane lung. Understanding these interactions is essential to understand the utility and limitations of different approaches to respiratory monitoring during ECMO. We present a summary of the underlying physiology of native and membrane lung gas exchange and describe different tools for titrating and monitoring gas exchange during ECMO. However, the most important role of VV ECMO in severe respiratory failure is as a means of avoiding further ergotrauma. Although optimal respiratory management during ECMO has not been defined, over the last decade there have been advances in multimodal respiratory assessment which have the potential to guide care. We describe a combination of imaging, ventilator-derived or invasive lung mechanic assessments as a means to individualise management during ECMO. [ABSTRACT FROM AUTHOR]

Critical intensity determination often requires costly tools and several testing sessions. Alternative approaches display relatively large individual variation. Therefore, simpler estimations with improved precision are needed. This study evaluated whether averaging the heart rate (HR) and oxygen uptake (VO2) responses associated with the muscle deoxyhemoglobin concentration breakpoint ([HHb]BP) and the heart rate variability (HRV) given by the detrended fluctuation analysis second threshold (HRVT2) during ramp incremental (RI) test improved the accuracy of identifying the HR and VO2 at the respiratory compensation point (RCP). Ten female and 11 male recreationally trained subjects performed a 15 W·minute21 RI test. Gas exchange, near-infrared spectroscopy (NIRS), and RR interval were recorded to assess the RCP, [HHb]BP, and HRVT2. Heart rate (mean6SD: 158614, 1566 13, 160 6 14 and, 158 6 12 bpm) and VO2 (3.08 6 0.69, 2.98 6 0.58, 3.06 6 0.65, and 3.02 6 0.60 L·minute21) at the RCP, [HHb]BP, HRVT2, and HRVT2&[HHb]BP average (H&HAv), respectively, were not significantly different (p. 0.05). The linear relationship between H&HAv and RCP was higher compared with the relationship between [HHb]BP vs RCP and HRVT2 vs RCP for both HR(r50.85; r50.73; r50.79, p.0.05) and VO2 (r50.94; r50.93; r50.91, p.0.05). Intraclass correlation between RCP, [HHb]BP, HRVT2, and H&HAV was 0.93 for VO2 and 0.79 for HR. The [HHb]BP and the HRVT2 independently provided VO2 and HR responses that strongly agreed with those at the RCP. Combining [HHb]BP and the HRVT2 resulted in estimations of the VO2 and HR at the RCP that displayed smaller variability compared with each modality alone. [ABSTRACT FROM AUTHOR]

Background: Pro-thrombotic changes are stimulated by Corona Virus as it has an affinity for endothelium and lung structures and this may explain its association with thrombotic events, reduction of pulmonary gas exchange, respiratory distress, and death. D-dimer is a specific marker of the breakdown of a fibrin clot and has been used as a diagnostic and prognostic marker in VTE and other coagulation disorders. So this study was conducted to assess the correlation of the D-Dimer levels with demographic profile and disease severity among COVID-19 patients. Methods: This was a Retrosprctive observational study. Four hundred and twenty (420) covid-19 positive patients were studied at tertiary care hospital KRIMS, Karwar, from July-2021 to December-2021. A citrate sample was collected of all patients who tested positive for the covid-19 disease. Citrated plasma was separated from each sample after proper centrifugation. Hemolysed samples and samples with insufficient quantity were rejected. In such cases, a new sample of the same patient was collected. D dimer test was then carried out from separated citrate plasma. Cut off value for d-dimer is 0.5 [Positive: >0.5 Fibrinogen equivalent units (FEU)/ml]. Result: From 420 cases: 290 males and 130 Females affected with peak occurrence in their sixth and seventh decade. A similar distribution pattern was found with a High D-dimer level also. The majority of the patients with elevated d-dimer levels had moderate to severe symptoms and required hospitalization. Conclusion: A significant correlation is found between elderly age with elevated d-dimer level, and it was found to be more common in female patients(50.76%). So, d-dimer is one of the most important tests to be carried out in a hospitalized novel corona disease patient for preventing thrombotic events with timely interventions guided by d-dimer level. [ABSTRACT FROM AUTHOR]

Introduction: Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder with a mutation in the PHOX2B gene. Patients need ventilatory support by noninvasive ventilation or tracheostomy to treat alveolar hypoventilation. Patients with CCHS have a defect in chemosensitivity signal integration. Recently, due to the COVID-19 pandemic, the entire world has had to get used to wearing medical masks (MM). Objectives: The aim of the study was to evaluate the effect of an MM on gas exchange and to determine the role of central and peripheral chemoresponsiveness on the partial pressure of transcutaneous carbon dioxide (PtcCO2) in patients with CCHS wearing an MM. Methods: This study was based on the analysis of recordings obtained without and with an MM during hospitalization and was conducted to assess the impact of MM on PtcCO2 and SpO2 recordings with the SenTec Digital Monitor and their relationships with peripheral CO2 chemosensitivity obtained during tidal breathing measurement and with the hypercapnic hyperoxic ventilatory response. Results: Sixteen patients were included (13 boys) and were 10.2 (7.5; 18.5) years old. The use of an MM had a negative impact on gas exchange in patients with CCHS. The median PtcCO2 increased significantly. Peripheral chemosensitivity correlated with MM-induced PtcCO2 changes (R = −0.72, p = 0.005), but central chemosensitivity (the hypercapnic ventilator response slope) did not (R = −0.22, p = 0.510). Conclusion: The use of an MM had a negative impact on gas exchange in patients with CCHS. [ABSTRACT FROM AUTHOR]

Nearly 40 yr ago, Professor Dempsey delivered the 1985 ACSM Joseph B. Wolffe Memorial Lecture titled: "Is the lung built for exercise?" Since then, much experimental work has been directed at enhancing our understanding of the functional capacity of the respiratory system by applying complex methodologies to the study of exercise. This review summarizes a symposium entitled: "Revisiting 'Is the lung built for exercise?'" presented at the 2022 American College of Sports Medicine annual meeting, highlighting the progress made in the last three-plus decades and acknowledging new research questions that have arisen. We have chosen to subdivide our topic into four areas of active study: (i) the adaptability of lung structure to exercise training, (ii) the utilization of airway imaging to better understand how airway anatomy relates to exercising lung mechanics, (iii) measurement techniques of pulmonary gas exchange and their importance, and (iv) the interactions of the respiratory and cardiovascular systemduring exercise. Each of the four sections highlights gaps in our knowledge of the exercising lung. Addressing these areas that would benefit from further study will help us comprehend the intricacies of the lung that allow it to meet and adapt to the acute and chronic demands of exercise in health, aging, and disease. [ABSTRACT FROM AUTHOR]

The effort to minimize VILI risk must be multi-pronged. The need to adequately ventilate, a key determinant of hazardous power, is reduced by judicious permissive hypercapnia, reduction of innate oxygen demand, and by prone body positioning that promotes both efficient pulmonary gas exchange and homogenous distributions of local stress. Modifiable ventilator-related determinants of lung protection include reductions of tidal volume, plateau pressure, driving pressure, PEEP, inspiratory flow amplitude and profile (using longer inspiration to expiration ratios), and ventilation frequency. Underappreciated conditional cofactors of importance to modulate the impact of local specific power may include lower vascular pressures and blood flows. Employed together, these measures modulate ventilation power with the intent to avoid VILI while achieving clinically acceptable targets for pulmonary gas exchange. [ABSTRACT FROM AUTHOR]

Purpose: Exercise prescription based on fixed heart rate (HR) values is not associated with a specific work rate (WR) during prolonged exercise. This phenomenon has never been evaluated in cardiac patients andmight be associated with a slow component of HR kinetics and β-adrenergic activity. The aims were to quantify, in cardiac patients, theWR decrease at a fixedHR and to test if it would be attenuated by β-blockers. Methods: Seventeen patients with coronary artery disease in stable conditions (69 ± 9 yr) were divided into two groups according to the presence (BB) or absence (no-BB) of a therapy with β-blockers, and performed on a cycle ergometer: an incremental exercise (INCR) and a 15-min "HRCLAMPED" exercise, in whichWRwas continuously adjusted to maintain a constant HR, corresponding to the gas exchange threshold +15%. HR was determined by the ECG signal, and pulmonary gas exchange was assessed breath-by-breath. Results: During INCR, HRpeak was lower in BB versus no-BB (P < 0.05), whereas no differences were observed for other variables. During HRCLAMPED, the decrease in WR needed to maintain HR constant was less pronounced in BB versus no-BB (-16% ± 10% vs -27 ± 10, P = 0.04) and was accompanied by a decreased VO2 only in no-BB (-13% ± 6%, P < 0.001). Conclusions: The decrease in WR during a 15-min exercise at a fixed HR (slightly higher than that at gas exchange threshold) was attenuated in BB, suggesting a potential role by β-adrenergic stimulation. The phenomenon may represent, also in this population, a sign of impaired exercise tolerance and interferes with aerobic exercise prescription. [ABSTRACT FROM AUTHOR]

Background: Optimization of pulmonary to systemic blood flow (Qp:Qs) is the key to postoperative care of children with a single-ventricular heart. The ratio of end tidal CO2 to partial pressure of CO2 called alveolar functional fraction (AFF) has shown a strong relationship with Qp:Qs in the catheterization lab in this population (with Qp:Qs of 1 correlating with AFF of 0.7). As there are no studies to understand the relationship between AFF and clinical outcomes in the postoperative care of these children, this study was carried out. Methodology and Results: This retrospective cohort study included 29 postoperative periods of children who underwent surgery for a single-ventricular heart. The average AFF was calculated for each early postoperative period. The primary clinical outcome was time in hours to normalize lactate. Other clinical outcomes included duration of mechanical ventilation, duration of milrinone infusion; presence of acute kidney injury (AKI), seizures and necrotizing enterocolitis (NEC); need for tracheostomy, need for extra-corporeal support, and mortality in the first 60 days postoperatively. The study population was divided into Group 1 with AFF ≤0.7 and Group 2 with AFF >0.7, to compare the outcome differences between the groups. Time to normalize the lactate had a modest negative correlation with the AFF, with Pearson's r = -0.49 (P = 0.007) for the entire cohort. The clinical outcomes were not statistically different for groups with AFF ≤0.7 and with AFF >0.7, although the group with AFF ≤0.7 had a higher incidence of NEC and higher mortality, whereas the group with AFF >0.7 had a higher incidence of AKI. Conclusions: In this small study, the AFF showed a modest negative correlation with the time to normalize lactate in postoperative care after surgery for a single ventricle heart. There were the trends with some other important clinical outcomes but not statistically significant. A larger, multi center study is needed to delineate these relationships further. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the changes in blood viscosity, pulmonary hemodynamics, nitric oxide (NO) production, and maximal oxygen uptake ( V ˙ O 2 max) during a maximal incremental test conducted in normoxia and during exposure to moderate altitude (2,400 m) in athletes exhibiting exercise-induced hypoxemia at sea level (EIH). Nine endurance athletes with EIH and eight without EIH (NEIH) performed a maximal incremental test under three conditions: sea level, 1 day after arrival in hypoxia, and 5 days after arrival in hypoxia (H5) at 2,400 m. Gas exchange and oxygen peripheral saturation (SpO2) were continuously monitored. Cardiac output, pulmonary arterial pressure, and total pulmonary vascular resistance were assessed by echocardiography. Venous blood was sampled before and 3 min after exercise cessation to analyze blood viscosity and NO end-products. At sea level, athletes with EIH exhibited an increase in blood viscosity and NO levels during exercise while NEIH athletes showed no change. Pulmonary hemodynamics and aerobic performance were not different between the two groups. No between-group differences in blood viscosity, pulmonary hemodynamics, and V ˙ O 2 max were found at 1 day after arrival in hypoxia. At H5, lower total pulmonary vascular resistance and greater NO concentration were reported in response to exercise in EIH compared with NEIH athletes. EIH athletes had greater cardiac output and lower SpO2 at maximal exercise in H5, but no between-group differences occurred regarding blood viscosity and V ˙ O 2 max. The pulmonary vascular response observed at H5 in EIH athletes may be involved in the greater cardiac output of EIH group and counterbalanced the drop in SpO2 in order to achieve similar V ˙ O 2 max than NEIH athletes. [ABSTRACT FROM AUTHOR]

Sarcoidosis is characterized by non-necrotizing granulomatous aggregations affecting a range of organs, with thoracic structures involved in 90% to 95% of cases. This granulomatous disease can impact the pulmonary vasculature via different mechanisms resulting in sarcoidosis-associated pulmonary hypertension (SAPH). These include postcapillary disease (left heart disease), immune-mediated granulomatous vasculopathy, hypoxemia, thromboembolism, pulmonary vascular compression and/or stenosis by mediastinal lymph nodes/fibrosis, or sarcoidosis-related portal hypertension. SAPH is a serious complication, especially in those with end-stage lung disease. A thorough evaluation is crucial to delineate the predominant mechanism of PH in the affected individual. The management of SAPH is complex and necessitates a personalized, multifaceted approach, targeting the specific mechanisms and underlying pathologies. Such patients are best served at specialized Pulmonary Hypertension and Sarcoidosis Centers. A notable phenotype within SAPH is the "pulmonary arteriopathy" group, characterized by milder parenchymal disease and a favorable response to PAH-targeted therapy, whereas patients with active granulomatous inflammation are likely to respond to immunosuppression. Several PAH therapies have been used to treat SAPH, however, clear direction on the use of PAH therapies in SAPH is still lacking. Patients receiving pulmonary vasodilators should be carefully monitored for potential deterioration in gas exchange or development of pulmonary edema, which could suggest underlying left heart disease or pulmonary veno-occlusive disease. Timely referral for lung transplant evaluation is crucial for those with SAPH and severe parenchymal lung disease, ensuring a comprehensive and patient-centered care approach. Much work remains to be done to understand the exact pathogenesis of SAPH, as well as to develop therapies that clearly improve outcomes for these patients. [ABSTRACT FROM AUTHOR]

The time-of-day effect of exercise on human function remains largely equivocal. Hence, this study aimed to further analyze the existing evidence concerning diurnal variations in cardiorespiratory responses and endurance performance using a meta-analytic approach. Literature search was conducted through databases, including PubMed, CINAHL, and Google Scholar. Article selection was made based on inclusion criteria concerning subjects' characteristics, exercise protocols, times of testing, and targeted dependent variables. Results on oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio, and endurance performance in the morning (AM) and late afternoon or evening (PM) were extracted from the chosen studies. Metaanalysis was conducted with the random-effects model. Thirty-one original research studies that met the inclusion criteria were selected. Meta-analysis revealed higher resting VO2 (Hedges' g = -0.574; p = 0.040) and resting HR (Hedges' g= -1.058; p = 0.002) in PM than in AM. During exercise, although VO2 remained indifferent between AM and PM, HR was higher in PM at submaximal (Hedges' g = -0.199; p = 0.046) and maximal (Hedges' g = -0.298; p = 0.001) levels. Endurance performance as measured by time-to-exhaustion or the total work accomplished was higher in PM than in AM (Hedges' g = -0.654; p = 0.001). Diurnal variations in VO2 appear less detectable during aerobic exercise. The finding that exercising HR and endurance performance were greater inPMthan in AMemphasizes the need to consider the effect of circadian rhythm when evaluating athletic performance or using HR as a criterion to assess fitness or monitor training. [ABSTRACT FROM AUTHOR]

Objective: Severe pneumonia is an important cause of mortality in coronavirus disease-2019 (COVID-19) infection. This study evaluated pulmonary gas exchange and mortality according to nasal cannula, high flow nasal cannula, non-invasive positive pressure ventilation and invasive mechanical ventilation used for treating hypoxemic respiratory failure in severe COVID-19 patients. Materials and Methods: Hundred and forty severe COVID-19 patients who were treated in Department of Anesthesiology Intensive Care Unit of Pamukkale University Hospital were reviewed retrospectively. Arterial blood gas results on the 1st, 3rd, 7th, 14th, and 21st days of admission were recorded. Results: The alveolo-arterial oxygen gradient of the patients receiving oxygen via nasal cannula was significantly lower than the patients receiving high-flow nasal cannula, non-invasive and invasive mechanical ventilation. When the other groups were compared, no significant difference was observed between the alveolo-arterial oxygen gradients of the patients who received high-flow nasal cannula, non-invasive and invasive mechanical ventilation support. We observed that the mortality of the patients who were admitted as intubated was significantly higher than the other groups. Conclusion: Invasive and non-invasive oxygen support resulted in similar alveolo-arterial oxygen gradients in severe COVID-19 patients at admission and at 3-week follow-up, but mortality was higher in intubated patients. [ABSTRACT FROM AUTHOR]

Deep neck infections are serious conditions and can present with acute upper airway obstruction. Our priority in the treatment is to ensure airway safety, and tracheotomy may be needed to overcome the upper airway obstruction. Unceasing dyspnea after tracheotomy should suggest serious pulmonary pathologies in patients with upper airway obstruction due to deep neck infection. Acute/chronic obstruction resolved after tracheotomy or upper respiratory tract surgical procedures of obstructive sleep apnea patients can turn into severe dyspnea with pulmonary edema. In this report, we present a 46-year-old male patient with negative pressure pulmonary edema as a complication of tracheotomy. The tracheotomy was performed due to severe upper airway obstruction secondary to a deep neck infection. The importance of early diagnosis and prompt treatment of this rare entity after unceasing dyspnea despite tracheotomy is discussed in the light of the current literature. [ABSTRACT FROM AUTHOR]

TEMPI syndrome is a new and poorly understood disease that is currently considered a type of plasma cell neoplasm with paraneoplastic manifestations. The TEMPI acronym defines the hallmarks of the syndrome: T for telangiectasia; E for erythrocytosis with elevated erythropoietin; M, monoclonal gammopathy; P, perinephric collections; and I, intrapulmonary shunting. Due to the marked erythrocytosis as the most common presenting feature, TEMPI is often misdiagnosed as polycythemia vera. However, unlike polycythemia vera, TEMPI is not associated with a JAK2 mutation. The pathogenesis of TEMPI syndrome is unknown, although a few hypothetical disease mechanisms have been previously discussed. Here we present a new case of TEMPI syndrome, discuss results of a next-generation sequencing (NGS) panel covering 1,425 known cancer-related genes, and review the current literature with focus on an update of the genetics of TEMPI syndrome. This is the first report of TEMPI that includes results of comprehensive NGS testing. [ABSTRACT FROM AUTHOR]

Background: The metabolic state of pulmonary artery smooth muscle cells (PASMCs) from patients with pulmonary arterial hypertension (PAH) is not well understood. In this study, we examined the balance between glycolysis and mitochondrial respiration in non-PAH-PASMCs and PAH-PASMCs under normoxia and hypoxia. Methods: We investigated the enzymes involved in glycolysis and mitochondrial respiration, and studied the two major energy-yielding pathways (glycolysis and mitochondrial respiration) by measuring extracellular acidification rate (ECAR) and cellular oxygen consumption rate (OCR) using the Seahorse extracellular flux technology. Results: Under both normoxia and hypoxia, the mRNA and protein levels of pyruvate dehydrogenase kinase 1 and pyruvate dehydrogenase were increased in PAH-PASMCs compared with non-PAH-PASMCs. The mRNA and protein levels of lactate dehydrogenase, as well as the intracellular lactate concentration, were also increased in PAH-PASMCs compared with non-PAH-PASMCs under normoxia. However, these were not significantly increased in PAH-PASMCs compared with non-PAH-PASMCs under hypoxia. Under normoxia, ATP production was significantly lower in PAH-PASMCs (59 ± 5 pmol/min) than in non-PAH-PASMCs (70 ± 10 pmol/min). On the other hand, ATP production was significantly higher in PAH-PASMCs (31 ± 5 pmol/min) than in non-PAH-PASMCs (14 ± 3 pmol/min) under hypoxia. Conclusions: There is an underlying change in the metabolic strategy to generate ATP production under the challenge of hypoxia. [ABSTRACT FROM AUTHOR]

We designed a photo-ECMO device to speed up the rate of carbon monoxide (CO) removal by using visible light to dissociate CO from hemoglobin (Hb). Using computational fluid dynamics, fillets of different radii (5 cm and 10 cm) were applied to the square shape of a photo-ECMO device to reduce stagnant blood flow regions and increase the treated blood volume while being constrained by full light penetration. The blood flow at different flow rates and the thermal load imposed by forty external light sources at 623 nm were modeled using the Navier-Stokes and convection–diffusion equations. The particle residence times were also analyzed to determine the time the blood remained in the device. There was a reduction in the blood flow stagnation as the fillet radii increased. The maximum temperature change for all the geometries was below 4 °C. The optimized device with a fillet radius of 5 cm and a blood priming volume of up to 208 cm3 should decrease the time needed to treat CO poisoning without exceeding the critical threshold for protein denaturation. This technology has the potential to decrease the time for CO removal when treating patients with CO poisoning and pulmonary gas exchange inhibition. [ABSTRACT FROM AUTHOR]

Cardiorespiratory fitness measured as ˙VO2 max is considered an important variable in the risk prediction of cardiovascular disease and all-cause mortality. Non-exercise ˙VO2 max prediction models are applicable, but lack accuracy. Here a model for the prediction of ˙VO2 max using seismocardiography (SCG) was investigated. 97 healthy participants (18–65 yrs., 51 females) underwent measurement of SCG at rest in the supine position combined with demographic data to predict ˙VO2 max before performing a graded exercise test (GET) on a cycle ergometer for determination of ˙VO2 max using pulmonary gas exchange measurements for comparison. Accuracy assessment revealed no significant difference between SCG and GET ˙VO2 max (mean±95% CI; 38.3±1.6 and 39.3±1.6 ml·min−1 ·kg−1 , respectively. P=0.075). Further, a Pearson correlation of r=0.73, a standard error of estimate (SEE) of 5.9 ml·min−1 ·kg−1 , and a coefficient of variation (CV) of 8±1% were found. The SCG ˙VO2 max showed higher accuracy, than the non-exercise model based on the FRIENDS study, when this was applied to the present population (bias=−3.7±1.3 ml·min−1 ·kg−1 , p<0.0001. r=0.70. SEE=7.4 ml·min−1 ·kg−1 , and CV=12±2%). The SCG ˙VO2 max prediction model is an accurate method for the determination of ˙VO2 max in a healthy adult population. However, further investigation on the validity and reliability of the SCG ˙VO2 max prediction model in different populations is needed for consideration of clinical applicability. [ABSTRACT FROM AUTHOR]

Introduction: Pulmonary complications in systemic sclerosis (SSc) significantly increase morbidity and mortality. Our aim was to determine the factors limiting exercise capacity in SSc patients with and without interstitial lung disease (ILD), and to identify and quantify abnormalities during exercise that might assist in clinical assessment of this complication. Methods: Fifteen patients with SSc and ILD (SSc‐ILD) were compared with 10 patients with SSc without ILD and 9 age‐ and sex‐matched normal volunteers. Subjects performed symptom‐limited incremental treadmill exercise with online measurement of respiratory gas exchange, arterial blood gas sampling and measurement of neurohormones in venous blood. Results: Patients with SSc‐ILD had lower exercise capacity than SSc patients without ILD or normal subjects (peak oxygen consumption (PV̇O2) (17.1 [4.2] vs. 22.0 [4.7] and 23.0 [5.4] ml kg−1 min−1, respectively, mean [SD], p < 0.01 ANOVA), but PV̇O2 did not correlate with static pulmonary function measurements. Ventilatory equivalent for CO2 (V̇E/V̇CO2; nadir) was higher in SSc‐ILD patients than the other two groups (36.6 [8.0] vs. 29.9 [4.4] and 30.0 [2.5], p < 0.005) as were peak exercise dead‐space tidal volume ratio (0.44 [0.06] vs. 0.26 [0.09] and 0.26 [0.05], p < 0.001) and peak exercise alveolar–arterial difference (28.9 [16.9] vs. 18.8 [14.0] and 11.5 [6.9] mmHg, p < 0.05). Atrial natriuretic peptide was elevated in both SSc patient groups. Conclusions: SSc‐ILD results in lower exercise capacity than SSc without ILD, and abnormalities of gas exchange are seen. The possible use of cardiopulmonary exercise testing to identify disease and quantify impairment in SSc‐ILD merits further study. [ABSTRACT FROM AUTHOR]

Background: Systemic sclerosis (SSc) associated interstitial lung disease (ILD) is a common complication of SSc, with a high mortality, despite current available treatments. Rituximab has shown some promising, although varied, results for the treatment of SSc‐ILD. Aims: To determine whether rituximab stabilised or improved pulmonary function at 12 months, in patients with SSc‐ILD. Methods: A retrospective analysis of patients with SSc‐ILD who progressed despite conventional therapy and received rituximab between 2008 and 2019 was performed at two tertiary centres. Baseline percentage forced vital capacity (FVC) and percentage diffusing capacity of carbon monoxide (DLCO) were compared with 1‐year post the first dose of rituximab. Mean and median change in FVC (%) and DLCO (%) were calculated. For those with available data, the FVC (%) and DLCO (%) 2 years and 1 year prior to rituximab were compared with the change 12‐months post‐rituximab. Results: Thirteen patients were included in the analysis. All patients demonstrated stability in their pulmonary function testing at 1‐year post‐rituximab. The mean FVC (%) was 57.18 (±16.93 standard deviation (SD)) prior to rituximab and 59.75 (±18.83 SD) 12‐month post‐rituximab, demonstrating an increase of 2.57 (±4.70 SD; P‐value 0.07). The mean DLCO (%) increased from 37.10 (±18.41 SD) prior to rituximab to 38.03 (±19.83) post‐rituximab. The mean change in DLCO (%) was 0.93 (±5.05 SD; P‐value 0.53). In the 2 years preceding rituximab, the mean FVC (%) and DLCO (%) declined by 9.25 and 9.66 respectively. Conclusion: This case series suggests that rituximab might stabilise pulmonary function tests, and delay deterioration in patients with progressive SSc‐ILD. These findings add to the growing body of evidence suggesting a role for rituximab in the treatment of SSc‐ILD. [ABSTRACT FROM AUTHOR]

Background: Patients with fibromyalgia (FM) exhibit low peak oxygen uptake ( V ˙ O2peak). We aimed to detect the contribution of cardiac output to ( Q ˙ ) and arteriovenous oxygen difference [ C (a-v) O 2 ] to V ˙ O 2 from rest to peak exercise in patients with FM. Methods: Thirty-five women with FM, aged 23 to 65 years, and 23 healthy controls performed a step incremental cycle ergometer test until volitional fatigue. Alveolar gas exchange and pulmonary ventilation were measured breath-by-breath and adjusted for fat-free body mass (FFM) where appropriate. Q ˙ (impedance cardiography) was monitored. C (a-v) O 2 was calculated using Fick's equation. Linear regression slopes for oxygen cost (∆ V ˙ O2/∆work rate) and Q ˙ to V O2 (∆ Q ˙ /∆ V ˙ O2) were calculated. Normally distributed data were reported as mean ± SD and non-normal data as median [interquartile range]. Results: V ˙ O2peak was lower in FM patients than in controls (22.2 ± 5.1 vs. 31.1 ± 7.9 mL∙min−1∙kg−1, P < 0.001; 35.7 ± 7.1 vs. 44.0 ± 8.6 mL∙min−1∙kg FFM−1, P < 0.001). Q ˙ and C(a-v)O2 were similar between groups at submaximal work rates, but peak Q ˙ (14.17 [13.34–16.03] vs. 16.06 [15.24–16.99] L∙min−1, P = 0.005) and C(a-v)O2 (11.6 ± 2.7 vs. 13.3 ± 3.1 mL O2∙100 mL blood−1, P = 0.031) were lower in the FM group. No significant group differences emerged in ∆ V ˙ O2/∆work rate (11.1 vs. 10.8 mL∙min−1∙W−1, P = 0.248) or ∆ Q ˙ /∆ V ˙ O2 (6.58 vs. 5.75, P = 0.122) slopes. Conclusions: Both Q ˙ and C(a-v)O2 contribute to lower V ˙ O2peak in FM. The exercise responses were normal and not suggestive of a muscle metabolism pathology. Trial registration: ClinicalTrials.gov, NCT03300635. Registered 3 October 2017—Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03300635. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the association between changes in FABP4 concentration and hormone and metabolite levels during and after acute low- and moderate-intensity aerobic exercise in healthy men. Eleven healthy men (24.4±1.4 years) were administered three trials in random order: 1) low-intensity aerobic exercise trial (LE trial; acute exercise at 40% peak oxygen uptake [Vo2 peak]+bed rest), 2) moderate-intensity aerobic exercise trial (ME trial: acute exercise at 60%Vo2 peak+bed rest), and 3) bed rest (Con trial). Expired gas and venous blood samples were collected at baseline, and immediately, 30 and 60 min after exercise, and substrate oxidation and hormone, metabolite, and FABP4 concentrations were measured. FABP4 concentration did not increase during aerobic exercise in LE and ME trials (p>0.05). However, FABP4 concentration significantly increased after the acute aerobic exercise in both the LE and ME trials (p≤0.003). Increased FABP4 concentration after acute exercise was not correlated with adrenaline, noradrenaline, other hormone, and metabolite concentration changes. These findings suggest that FABP4 concentration increases after acute aerobic exercise independently of exercise intensity. Furthermore, increased FABP4 concentration after acute aerobic exercise may not be involved in the magnitude of adrenaline, noradrenaline, and lipolytic response. [ABSTRACT FROM AUTHOR]