Assessment of Relative Energy Deficiency in Sport (REDs) Risk among Adolescent Acrobatic Gymnasts.

Energy imbalance exposes athletes to relative energy deficiency in sports (REDs) syndrome. Data on energy consumption, REDs, and bone mineral density (BMD) in adolescent acrobatic gymnasts, especially in males, are scarce. Our aim was to examine the eating habits, energy balance, body composition, and BMD of these athletes. In this study, 18 healthy adolescents participating in competitive acrobatic gymnastics completed a questionnaire, underwent a dual-energy X-ray absorptiometry scan (DXA), received a food log, and had their activities monitored for 3 days. Eighteen acrobats were enrolled (mean age: 14.3 ± 1.2 years; males: 6/18). The mean total body BMD Z-score was 0.4 ± 1.0. Top-position acrobats (7/18) had significantly lower total body BMD Z-scores than base-positioned acrobats (-0.2 ± 0.3 vs. 0.8 ± 0.3, p = 0.032), though their forearms were not significantly different (0.2 ± 0.5 vs. 0.8 ± 0.7, p = 0.331). No sex differences were found for BMD Z-scores, BMI, or energy availability. The BMD parameters of the acrobats were within the normal range for a healthy pediatric population, although three had low BMDs (<-1 SD) for healthy athletes. Total body and LS BMD Z-scores were significantly lower in top-position athletes compared to base-position athletes. These findings suggest personalized (top vs. base) training programs (high-impact training) that may achieve better health outcomes.

Eradication of Nontuberculous Mycobacteria in People with Cystic Fibrosis Treated with Elexacaftor/Tezacaftor/Ivacaftor: A Multicenter Cohort Study.

BACKGROUND: The prevalence of nontuberculous mycobacteria (NTM) infections is rising in people with cystic fibrosis (pwCF). NTM infection, especially infection with Mycobacterium abscessus complex (MABC), is commonly associated with severe lung deterioration. The current treatment modalities, including multiple intravenous antibiotics, frequently fail to achieve airway eradication. Although treatment with elexacaftor/tezacaftor/ivacaftor (ETI) has been shown to modulate the lung microbiome, data regarding its role in eradicating NTM in pwCF is lacking. Our aim was to evaluate the impact of ETI on the rate of NTM eradication in pwCF. METHODS: This retrospective multicenter cohort study included pwCF from five CF centers in Israel. PwCF aged older than 6 who had at least one positive NTM airway culture in the past two years and were treated with ETI for at least one year were included. The annual NTM and bacterial isolations, pulmonary function tests, and body mass index were analyzed before and after ETI treatment. RESULTS: Fifteen pwCF were included (median age 20.9 years, 73.3% females, 80% pancreatic insufficient). In nine patients (66%) NTM isolations were eradicated following treatment with ETI. Seven of them had MABC. The median time between the first NTM isolation and treatment with ETI was 2.71 years (0.27-10.35 years). Eradication of NTM was associated with improved pulmonary function tests (p<0.05). CONCLUSIONS: For the first time, we report successful eradication of NTM, including MABC, following treatment with ETI in pwCF. Additional studies are needed to assess whether treatment with ETI can result in the long-term eradication of NTM.

Signal Variability Comparative Analysis of Healthy Early- and Late-Pubertal Children during Cardiopulmonary Exercise Testing.

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 (V̇O 2 ), 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., V̇O 2 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 V̇O 2 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 V̇O 2 , 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.

Cardiopulmonary Exercise Testing Provides Prognostic Information in Advanced Cystic Fibrosis Lung Disease.

Rationale: Cardiopulmonary exercise testing (CPET) provides prognostic information in cystic fibrosis (CF); however, its prognostic value for patients with advanced CF lung disease is unknown. Objectives: To determine the prognostic value of CPET on the risk of death or lung transplant (LTX) within 2 years. Methods: We retrospectively collected data from 20 CF centers in Asia, Australia, Europe, and North America on patients with a forced expiratory volume in 1 second (FEV1) ⩽ 40% predicted who performed a cycle ergometer CPET between January 2008 and December 2017. Time to death/LTX was analyzed using mixed Cox proportional hazards regression. Conditional inference trees were modeled to identify subgroups with increased risk of death/LTX. Results: In total, 174 patients (FEV1, 30.9% ± 5.8% predicted) were included. Forty-four patients (25.5%) died or underwent LTX. Cox regression analysis adjusted for age, sex, and FEV1 revealed percentage predicted peak oxygen uptake ([Formula: see text]o2peak) and peak work rate (Wpeak) as significant predictors of death/LTX: adjusted hazard ratios per each additional 10% predicted were 0.60 (95% confidence interval, 0.43-0.90; P = 0.008) and 0.60 (0.48-0.82; P < 0.001). Tree-structured regression models, including a set of 11 prognostic factors for survival, identified Wpeak to be most strongly associated with 2-year risk of death/LTX. Probability of death/LTX was 45.2% for those with a Wpeak ⩽ 49.2% predicted versus 10.9% for those with a Wpeak > 49.2% predicted (P < 0.001). Conclusions: CPET provides prognostic information in advanced CF lung disease, and Wpeak appears to be a promising marker for LTX referral and candidate selection.

Pulmonary functions, nasal symptoms, and quality of life in patients with primary ciliary dyskinesia (PCD).

BACKGROUND: Several factors may influence quality of life (QOL) for patients with primary ciliary dyskinesia (PCD). We aimed to evaluate the association between pulmonary functions, nasal symptoms and QOL in PCD patients. METHODS: A prospective single center study. Patients performed spirometry, whole body plethysmography, forced oscillation technique (FOT), lung clearance index (LCI), 6-min walk test (6MWT), and filled two questionnaires: a specific PCD QOL questionnaire (PCD-QOL) and Sino-nasal outcome test (SNOT-22) questionnaire, assessing symptoms of chronic rhinosinusitis and health related QOL. RESULTS: Twenty-seven patients (56% females), age 19.4 ± 10.5 years were included; their, FEV1 was 74.6 ± 22.7%, and RV/TLC was (157.3 ± 39.3% predicted). Health perception and lower respiratory symptoms domains of PCD-QOL had the lowest score (median [IQR]: 50 [33.3-64.6] and 57.1 [38.9-72.2], respectively). FOT parameters correlated with several PCD-QOL domains. R5 z-score (indicating total airway resistance) and AX z-score (indicating airway reactance) correlated negatively with physical domain (r = -0.598, p = .001, and r = -0.42, p = .03, respectively); R5 z-score also correlated negatively with hearing domain (r = -0.57, p = .002). R5-20 z-score (indicating small airway resistance) correlated negatively with role domain (r = -0.49, p = .03). SNOT-22 score correlated negatively with several PCD-QOL domains (lower respiratory symptoms r = -0.77, p < .001; physical r = -0.72, p < .001; upper respiratory symptoms r = -0.66, p < .001). No correlations were found between spirometry values, LCI, 6MWT, and PCD-QOL. CONCLUSIONS: FOT suggested small airway dysfunction, and correlated negatively with several PCD-QOL domains. Nasal symptoms had strong negative correlations with PCD-QOL. Larger longitudinal studies will further elucidate factors affecting QOL in PCD.

Pediatric negative pressure pulmonary edema: Case series and review of the literature.

INTRODUCTION: Negative pressure pulmonary edema (NPPE) is a potentially life-threatening complication that develops rapidly following acute upper airway obstruction. The condition is rare, dramatic but resolves quickly. Prompt recognition and appropriate supportive treatment may prevent unnecessary investigations and iatrogenic complications. METHODS: We describe a spectrum of etiologies and clinical manifestation of pediatric NPPE in our center and review of previous publications. CONCLUSION: The etiology for the development of NPPE in children has shifted over the years. Although dramatic in presentation, this type of pulmonary edema often resolves quickly with minimal support.

The effect of inspiratory muscle training in PCD and CF patients: A pilot study.

BACKGROUND: Effective work of breathing and bronchial hygiene requires synergy of inspiratory and expiratory muscles. Inspiratory muscle training (IMT) is a part of pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD). There is some evidence of its efficacy in cystic fibrosis (CF) and, recently, in long COVID-19. We are not aware of studies on IMT in primary ciliary dyskinesia (PCD). Our aim was to assess the effect of IMT on respiratory muscle strength and pulmonary function in PCD and CF patients. METHODS: A single center pilot study. Spirometry, lung clearance index (LCI), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) were measured at baseline (visit 1), after a month of IMT with ®POWERbreathe (visit 2), and at follow-up (visit 3). RESULTS: The cohort included 27 patients (19 PCD, 8 CF); mean age 18.4 ± 9.8 years. After a month of IMT, there was a significant increase in MIP and MIP% (6.19-7.44, p = .015; and 81.85%-100.41%, p = .046, respectively), which was sustained at visit 3. Compliance ≥90% led to higher improvement in MIP. In sub-group analysis, improvement in MIP and MIP% remained significant for PCD patients (p = .026 and p = .049, respectively). No significant changes were found in spirometry, MEP or LCI. CONCLUSIONS: IMT was well-tolerated and led to improved inspiratory muscle strength in PCD patients. The clinical implication of improved MIP should be further investigated. Larger, long-term studies are needed to evaluate long-term effects of IMT on pulmonary function, respiratory muscle strength, pulmonary exacerbations, and quality of life.

The Impact of Respiratory Symptoms on the Risk of Serious Bacterial Infection in Febrile Infants < 60 Days Old.

OBJECTIVES: We aimed to evaluate the impact of respiratory symptoms and positive viral testing on the risk of serious bacterial infections (SBIs). METHODS: A retrospective study was conducted that included infants (0-60 days) presenting with a fever between 2001 and 2022 at a tertiary hospital in northern Israel. Demographic, clinical, and laboratory parameters were collected, and risk factors for SBIs were analyzed. RESULTS: Data from a total of 3106 infants, including data from blood, urine, and CSF cultures, were obtained in 96.6%, 89%, and 29% of cases, respectively. A fever without respiratory symptoms (fever only) was present in 1312 infants, while 1794 had a fever and respiratory symptoms-427 were positive for a respiratory virus (virus+), 759 tested negative (virus-), and 608 were not tested. The SBI rate was 5.1% vs. 7.5% in the fever-and-respiratory group vs. the fever-only group (p = 0.004, OR = 0.65 (95% CI = 0.49-0.88)) and 2.8% vs. 7% in the virus+ vs. virus- group (p = 0.002, OR = 0.385, (95% CI = 0.203-0.728)). The male gender, an age < 1 month, leukocytosis > 15 × 109/L, or a CRP > 2 mg/dL increased the risk of SBIs. Respiratory symptoms or a confirmed viral infection reduced the risk of SBIs in the presence of the above risk factors. CONCLUSIONS: Respiratory symptoms and a positive viral test decreased the risk of SBIs. Combining rapid viral testing with clinical variables may identify low-risk infants. Despite the relatively low risk of SBIs in individuals with viral infections, conducting prospective studies remains essential for accurately predicting the occurrence of these potentially life-threatening infections.

The effect of nose clip on exercise-induced bronchoconstriction in adolescents.

BACKGROUND: Oral breathing is considered to increase hyper-responsiveness of the airways. Data on the need for nose clip (NC) during exercise challenge test (ECT) in children and adolescents is scarce. Ouraim was to evaluate the role of NC during ECT in children and adolescents. METHODS: A prospective, cohort study; children referred for ECT were evaluated on two separate visits, with and without a NC. Demographic, clinical data and measurements of lung functions were recorded. Allergy and asthma control were evaluated by Total Nasal Symptoms Score (TNSS) and Asthma Control Test (ACT) questionnaires. RESULTS: Sixty children and adolescents (mean age 16.7 ± 1.1 years, 38% Female,) performed ECT with NC and 48 (80%) completed visit 2 (ECT without NC), 8.7 ± 7.9 days after visit 1. Following exercise, 29/48 patients (60.4%) with NC had a decline of ≥12% in forced expiratory volume in the first second (FEV1 ) (positive ECT) compared to only 16/48 (33.3%) positive tests without NC (p = 0.0008). Test result was changed in 14 patients from positive ECT (with NC) to negative ECT (no NC) and in only one patient from negative to positive. The use of NC resulted in greater FEV1 decline (median 16.3% predicted, IQR 6.0-19.1% predicted vs. median 4.5% predicted, IQR 1.6-18.4% predicted, p = 0.0001), and better FEV1 increase after bronchodil at or inhalation compared to ECT without NC. Higher TNSS scores did not predict higher probability to positive ECT. CONCLUSIONS: The use of NC during ECT increases detection rate of exercise induced bronchoconstriction during ECT in the pediatric population. These findings strengthen the recommendation of nasal blockage during ECT in children and adolescents.

Significant exercise limitations after recovery from MIS-C related myocarditis.

BACKGROUND: Myocarditis is one of the presentations of multisystemic inflammatory syndrome in children (MIS-C) following coronavirus disease 2019 (COVID-19). Although the reported short-term prognosis is good, data regarding medium-term functional capacity and limitations are scarce. This study aimed to evaluate exercise capacity as well as possible cardiac and respiratory limitations in children recovered from MIS-C related myocarditis. METHODS: Fourteen patients who recovered from MIS-C related myocarditis underwent spirometry and cardiopulmonary exercise testing (CPET), and their results were compared with an age-, sex-, weight- and activity level-matched healthy control group (n = 14). RESULTS: All participants completed the CPET with peak oxygen uptake (peak [Formula: see text]), and the results were within the normal range (MIS-C 89.3% ± 8.9% and Control 87.9% ± 13.7% predicted [Formula: see text]). Five post-MIS-C patients (35%) had exercise-related cardio-respiratory abnormalities, including oxygen desaturation and oxygen-pulse flattening, compared to none in the control group. The MIS-C group also had lower peak exercise saturation (95.6 ± 3.5 vs. 97.6 ± 1.1) and lower breathing reserve (17.4% ± 7.5% vs. 27.4% ± 14.0% of MVV). CONCLUSIONS: Patients who recovered from MIS-C related myocarditis may present exercise limitations. Functional assessment (e.g., CPET) should be included in routine examinations before allowing a return to physical activity in post-MIS-C myocarditis. Larger, longer term studies assessing functional capacity and focusing on physiological mechanisms are needed.

Challenges in DICER1-Associated Lung Disease.

Pleuropulmonary blastoma (PPB) is a tumor occurring almost exclusively in infants and young children. This is the most common primary-lung malignancy in childhood. There is age-associated progression through a distinctive sequence of pathologic changes, from a purely multicystic lesion type I to a high-grade sarcoma type II and III. While complete resection is the cornerstone treatment for type I PPB, aggressive chemotherapy with a less favorable prognosis is associated with type II and III. DICER1 germline mutation is positive in 70% of children with PPB. Diagnosis is challenging, as it resembles congenital pulmonary airway malformation (CPAM) in imaging. Although PPB is an extremely rare malignancy, over the past five years we have encountered several children diagnosed with PPB in our medical center. Herein, we present some of these children and discuss diagnostic, ethical, and therapeutic challenges.

Pregnancy in Cystic Fibrosis-Past, Present, and Future.

The introduction of mutation-specific therapy led to a revolution in cystic fibrosis (CF) care. These advances in CF therapies have changed the disease profile from a severe incurable disease with limited survival to a treatable disease with improved quality of life and survival into adulthood. CF patients are now able to plan their future, including marriage and parenthood. Side by side with the optimism, new issues and concerns are arising, including fertility and preparation for pregnancy, maternal and fetal care during pregnancy, and post-partum care. While cystic fibrosis transmembrane regulator (CFTR) modulators show promising results for improving CF lung disease, data on their safety in pregnancy are still limited. We performed a literature review on pregnancy in CF from the past, with the first described pregnancy in 1960, through the current fascinating changes in the era of CFTR modulators, to ongoing studies and future directions. Current advances in knowledge give hope for improved outcomes of pregnancy, towards the best possible prognosis for the mother and for the baby.

Foreign body aspiration in Israeli children during the COVID-19 pandemic.

BACKGROUND: Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, there has been a decline in pediatric emergency department visits. Our aim was to assess the pattern of pediatric foreign body aspiration (FBA) during the first year of the COVID-19 pandemic, in comparison to the prior years. METHODS: In this retrospective multicenter study, we compared the number of children who presented with FBA during the COVID-19 year (March 1, 2020 to February 28, 2021) to the annual average of the years 2016-2019. We also compared the lockdown periods to the postlockdown periods, and the percentage of missed FBA, proven FBA, and flexible bronchoscopy as the removal procedure. RESULTS: A total of 345 children with FBA from six centers were included, 276 in the pre-COVID-19 years (average 69 per year) and 69 in the COVID-19 year. There was no difference in the prevalence of FBA between the COVID-19 year and any of the prior 4 years. Examining the lockdown effect, the monthly incidence of FBA dropped from a pre-COVID-19 average of 5.75 cases to 5.1 cases during lockdown periods and increased to 6.3 cases in postlockdown periods. No difference in the percentage of missed FB or proven FB was observed. There was a significant rise in the usage of flexible bronchoscopy as the removal procedure (average of 15.4% vs. 30.4%, p = 0.001). CONCLUSION: There were fewer cases of pediatric FBA during lockdown periods, compared to post-lockdown periods, presumably related to better parental supervision, with no difference in the prevalence of FBA during the COVID-19 year.

Effect of Trikafta on bone density, body composition and exercise capacity in CF: A pilot study.

BACKGROUND: While the positive effect of Trikafta on cystic fibrosis (CF) pulmonary disease is well established, there is limited data about its effect on bone mineral density (BMD), body composition and exercise capacity. METHODS: A pilot single center study. BMD and body composition were measured three months after the initiation of Trikafta (study group) and compared to values obtained 2 years earlier. CF patients not treated with Trikafta, for whom BMD was measured 2 years apart, served as controls. Spirometry, lung clearance index (LCI), sweat test, six-min walk test (6MWT) and cardio-pulmonary exercise test (CPET) were performed before and three months after the initiation of Trikafta. RESULTS: Nine study patients, aged 18.6 ± 4.7 years, and nine controls. For the study group, BMI and hip and spine BMD increased significantly (19.4 ± 2.6 to 20.3 ± 2.19 BMI, p = 0.05; 0.73 ± 0.098 to 0.81 ± 0.12 gr/cm2 hip, p = 0.017; 0.76 ± 0.14 to 0.82 ± 0.14 gr/cm2 spine, p = 0.025). For the control group, there was no difference in hip or spine BMD. Lean body mass, %fat z-score and fat mass/height2 z-score increased significantly (34770.23 ± 10521.21 to 37430.16 ± 10330.09gr, p = 0.017; -0.8 ± 0.75 to 0.46 ± 0.58, p = 0.012; and -0.98 ± 0.66 to -0.04 ± 0.51, p = 0.025, respectively). 6MWT improved from 541.1 ± 48.9 to 592.9 ± 54.5 m (p = 0.046). As expected, FEV1%pred increased (p = 0.008) and sweat chloride decreased significantly (p = 0.017). In CPET, VE/VCO2 improved, indicating better ventilatory efficiency. CONCLUSIONS: To the best of our knowledge, this is the first study evaluating the metabolic effects of Trikafta. The results are encouraging and offer hope beyond the well-established effect on pulmonary disease. Larger long-term studies are warranted to unpin the underlying physiological mechanisms.

Cardiopulmonary Exercise Testing in Childhood in Late Preterms: Comparison to Early Preterms and Term-Born Controls.

Background: Late preterm (340−366 weeks gestational age [GA]) infants may have abnormal pulmonary development and possible exercise physiology parameters. We aim to assess the effect of late prematurity on exercise capacity in childhood and to compare it to early preterm (EP) (born < 300 GA), and to term healthy control (TC) (>370 week GA). Methods: Late preterm and early preterm (7−10 years) completed a cardiopulmonary exercise test (CPET) and spirometry and were compared to EP and to TC. Results: Eighty-four children (age 9.6 ± 1.0 years, 48% girls) participated. Twenty-one former LP were compared to 38 EP (15 with Bronchopulmonary dysplasia (BPD) [EP+], 23 without BPD [EP−]) and to 25 TC children. Peak oxygen uptake (peakV̇O2) was statistically lower than in the TC, but within the normal range, and without difference from the EP (LP 90.2 ± 15.1%, TC 112.4 ± 16.9%, p < 0.001; EP+ 97.3 ± 25.5%, EP− 85.4 ± 20.8%, p = 0.016 and p < 0.001, respectively, when compared with TC). Lung function (FEV1) was lower than normal only in the EP+ (75.6 ± 14.9% predicted, compared with 12.5 ± 87.8 in EP−, 87.5 ± 16.9 in LP and 91.0 ± 11.7 in TC). Respiratory and cardiac limitations were similar between all four study groups. Conclusions: This study demonstrated lower exercise capacity (peakV̇O2) in former LP children compared with healthy term children. Exercise capacity in LP was comparable to that of EP, with and without BPD. However, the exercise test parameters, specifically peakV̇O2, were within the normal range, and no significant physiological exercise limitations were found.

Functional Data Analysis for Predicting Pediatric Failure to Complete Ten Brief Exercise Bouts.

Physiological response to physical exercise through analysis of cardiopulmonary measurements has been shown to be predictive of a variety of diseases. Nonetheless, the clinical use of exercise testing remains limited because interpretation of test results requires experience and specialized training. Additionally, until this work no methods have identified which dynamic gas exchange or heart rate responses influence an individual's decision to start or stop physical activity. This research examines the use of advanced machine learning methods to predict completion of a test consisting of multiple exercise bouts by a group of healthy children and adolescents. All participants could complete the ten bouts at low or moderate-intensity work rates, however, when the bout work rates were high-intensity, 50% refused to begin the subsequent exercise bout before all ten bouts had been completed (task failure). We explored machine learning strategies to model the relationship between the physiological time series, the participant's anthropometric variables, and the binary outcome variable indicating whether the participant completed the test. The best performing model, a generalized spectral additive model with functional and scalar covariates, achieved 93.6% classification accuracy and an F1 score of 93.5%. Additionally, functional analysis of variance testing showed that participants in the 'failed' and 'success' groups have significantly different functional means in three signals: heart rate, oxygen uptake rate, and carbon dioxide uptake rate. Overall, these results show the capability of functional data analysis with generalized spectral additive models to identify key differences in the exercise-induced responses of participants in multiple bout exercise testing.

Functional capacity and quality of life in patients with vascular ring.

BACKGROUND: Vascular rings are congenital anomalies of the aortic arch that compress the trachea and esophagus and may require corrective surgery. Data about the long-term effects of vascular rings are scarce. We aimed to evaluate the long-term cardiorespiratory, exercise capacity, and quality of life of vascular ring patients. METHODS: A single center prospective study evaluating spirometry, echocardiography, six-minute walk test (6MWT), cardiopulmonary exercise testing (CPET), and quality of life questionnaire (SF36) in patients with a diagnosis of vascular ring, with or without corrective surgery. RESULTS: Twenty-seven patients participated (11.9 ± 6 years, 52% males). The most common diagnosis was double aortic arch (16 patients, 59%). Nineteen patients had corrective surgery (O) and 8 did not (NO). Pulmonary function tests were within normal range in both groups (FEV1 % predicted O = 87.6 ± 16.5, NO = 83 ± 10.8%). However, 11/27 had abnormal FEV1 , 5 had abnormal FVC, and 13 (48%) had flattening of the expiratory curve. 6MWD and oxygen uptake were similarly mildly reduced in both groups; (6MWD O = 80.1 ± 10.7% predicted, NO = 74.1 ± 10.9% and oxygen uptake O = 78.5 ± 23.2% predicted, NO = 73.4 ± 14.3%). Peak O2 pulse (V̇O2 /HR% predicted) was mildly reduced in the NO group (O = 88.4 ± 17.3%, NO = 75.8 ± 16.2%). Echocardiogram and SF36 scores were normal in all patients. CONCLUSIONS: Long-term evaluation of patients born with vascular rings revealed mild pulmonary impairment, reduction in 6MWD, and oxygen uptake. The NO group had also mild reduced peak O2 pulse. Larger, long-term studies assessing functional parameters in operated and non-operated patients are needed to assess disease/surgery limitation in patients with vascular rings. Clinical trial registration number: NCT04781738.

Heart rate and gas exchange dynamic responses to multiple brief exercise bouts (MBEB) in early- and late-pubertal boys and girls.

Natural patterns of physical activity in youth are characterized by brief periods of exercise of varying intensity interspersed with rest. To better understand systemic physiologic response mechanisms in children and adolescents, we examined five responses [heart rate (HR), respiratory rate (RR), oxygen uptake (V̇O2 ), carbon dioxide production (V̇CO2 ), and minute ventilation (V̇E), measured breath-by-breath] to multiple brief exercise bouts (MBEB). Two groups of healthy participants (early pubertal: 17 female, 20 male; late-pubertal: 23 female, 21 male) performed five consecutive 2-min bouts of constant work rate cycle-ergometer exercise interspersed with 1-min of rest during separate sessions of low- or high-intensity (~40% or 80% peak work, respectively). For each 2-min on-transient and 1-min off-transient we calculated the average value of each cardiopulmonary exercise testing (CPET) variable (Y̅). There were significant MBEB changes in 67 of 80 on- and off-transients. Y̅ increased bout-to-bout for all CPET variables, and the magnitude of increase was greater in the high-intensity exercise. We measured the metabolic cost of MBEB, scaled to work performed, for the entire 15 min and found significantly higher V̇O2 , V̇CO2 , and V̇E costs in the early-pubertal participants for both low- and high-intensity MBEB. To reduce breath-by-breath variability in estimation of CPET variable kinetics, we time-interpolated (second-by-second), superimposed, and averaged responses. Reasonable estimates of τ (<20% coefficient of variation) were found only for on-transients of HR and V̇O2 . There was a remarkable reduction in τHR following the first exercise bout in all groups. Natural patterns of physical activity shape cardiorespiratory responses in healthy children and adolescents. Protocols that measure the effect of a previous bout on the kinetics of subsequent bouts may aid in the clinical utility of CPET.

Functional Capacity in Patients Who Recovered from Mild COVID-19 with Exertional Dyspnea.

BACKGROUND: Post mild COVID-19 dyspnea is poorly understood. We assessed physiologic limitations in these patients. METHODS: Patients with post mild COVID-19 dyspnea (group A) were compared (pulmonary function tests, 6-min walk test (6MWT), echocardiography and cardiopulmonary exercise test (CPET)) to post moderate/severe COVID-19 (group B) and to CPET and spirometry of patients with unexplained dyspnea (group C). RESULTS: The study included 36 patients (13 in A, 9 in B and 14 in C). Diffusion capacity was lower in group B compared to group A (64 ± 8 vs. 85 ± 9% predicted, p = 0.014). 6MWT was normal and similar in both patient groups. Oxygen uptake was higher in group A compared to groups B and C (108 ± 14 vs. 92 ± 13 and 91 ± 23% predicted, p = 0.013, 0.03, respectively). O2 pulse was normal in all three groups but significantly higher in the mild group compared to the control group. Breathing reserve was low/borderline in 2/13 patients in the mild group, 2/9 in the moderate/severe group and 3/14 in the control group (NS). CONCLUSIONS: Patients with post mild COVID-19 dyspnea had normal CPET, similar to patients with unexplained dyspnea. Other mechanisms should be investigated and the added value of CPET to patients with post mild COVID-19 dyspnea is questionable.