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OBJECTIVE: Cardiopulmonary exercise testing (CPET) is used prior to bariatric surgery in adolescents with obesity to assess surgical risk factors. Lack of normative equations for peak oxygen consumption (pVO2) for this population limits CPET interpretation. We aimed to use lean body weight (LBW) to predict pVO and developed novel predictive equations for use in this population. METHODS: 446 participants with obesity ages 9-20 underwent CPET prior to bariatric surgery from January 1, 2006 to December 31, 2019. Bioelectrical impedance analysis helped calculate LBW. Achieving peak heart rate > 90% predicted and RER of >1.1 were considered satisfactory effort. RESULTS: 107 CPET studies (29%) were satisfactory. Mean weight was 127 ± 21 kg, and BF% 49.7 ± 6.8, and LBW 63 ± 10, kg. Mean pVO was 22.2 ± 3.2 mL/kg/min. The mean pVO using LBW was 44.8 ± 8.7 mL/kg/min. Total body weight (TBW) estimated pVO to be 50.7 ± 7.0 % predicted[(1)](#ref-0001), while LBW estimated it at 102.3 ± 17.6 % predicted. Linear regression yielded reference equations pVO =1571.6+12.2*TBW (males) and pVO2=1301.8+10.6*TBW (females). CONCLUSION: When pVO is corrected for LBW, adolescents with obesity demonstrate normal pVO . A novel set of equations were developed to predict absolute pVO using TBW.

Background In the spring of 2020, New York City was an epicenter of coronavirus disease 2019 (COVID-19). The post-hospitalization needs of COVID-19 patients were not understood and no outpatient rehabilitation programs had been described. Objective To evaluate whether a virtual rehabilitation program would lead to improvements in strength and cardiopulmonary endurance when compared with no intervention in patients discharged home with persistent COVID-19 symptoms. Design Prospective cohort study. Setting Academic medical center. Patients Between April and July 2020, 106 patients discharged home with persistent COVID-19 symptoms were treated. Forty-four patients performed virtual physical therapy (VPT); 25 patients performed home physical therapy (HPT); 17 patients performed independent exercise program (IE); and 20 patients did not perform therapy. Interventions All patients were assessed by physiatry. VPT sessions were delivered via secure Health Insurance Portability and Accountability Act compliant telehealth platform 1-2 times/week. Patients were asked to follow up 2 weeks after initial evaluation. Main outcome measures Primary study outcome measures were the change in lower body strength, measured by the 30-second sit-to-stand test; and the change in cardiopulmonary endurance, measured by the 2-minute step test. Results At the time of follow-up, 65% of patients in the VPT group and 88% of patients in the HPT group met the clinically meaningful difference for improvement in sit-to-stand scores, compared with 50% and 17% of those in the IE group and no-exercise group (P = .056). The clinically meaningful difference for improvement in the step test was met by 74% of patients in the VPT group and 50% of patients in the HPT, IE, and no-exercise groups (P = .12). Conclusions Virtual outpatient rehabilitation for patients recovering from COVID-19 improved lower limb strength and cardiopulmonary endurance, and an HPT program improved lower limb strength. Virtual rehabilitation seems to be an efficacious method of treatment delivery for recovering COVID-19 patients.

Exercise stress testing is routinely performed to evaluate suspected coronary artery disease in older adults. However, the available data to predict and compare relative exercise capacity in the general population were developed using predominantly younger, healthy cohorts with few or no women. This study aimed to describe the exercise capacity of patients older than 75 years who underwent a clinically indicated Bruce protocol exercise stress test. This was a retrospective, cross-sectional study of 2,041 consecutive patients older than 75 years who performed a Bruce protocol exercise stress echocardiogram that was terminated because of maximal effort without ischemia at Columbia University Medical Center between April 10, 2009, and July 30, 2020. The analytic sample included 2,041 exercise stress tests in 786 women (median [interquartile range] age 79 [77 to 81] years) and 1,255 men (median [interquartile range] age 79 [77 to 82] years). Cardiovascular risk factors and clinical coronary disease were common and more prevalent in men than women. The median exercise time for men aged 76 to 80 years was 7:22 (minutes:seconds) and for women was 6:00 and significantly decreased in both genders as age increased (p

Background Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation for end-stage interstitial lung disease (ILD) and pulmonary hypertension (PH) has varying results based on ECMO configuration. We compare our experience using venovenous (VV) and venoarterial (VA) ECMO bridge to transplantation for ILD with PH on survival to successful transplantation. Methods A single-center retrospective review was done of patients with ILD and secondary PH who were placed on either VV or VA ECMO as bridge to transplantation from 2010 to 2016. Comparisons for factors associated with survival to transplantation between VV and VA ECMO strategies were made using Cox proportional hazards model. Subgroup analysis included comparisons of VV ECMO patients who remained on VV or were converted to VA ECMO. Results A total of 50 patients with ILD and PH were treated initially with either VV (n = 19) or VA (n = 31) ECMO as bridge to lung transplantation. Initial VA ECMO had a significantly higher survival to transplantation compared with initial VV ECMO (p = 0.03). Cox proportional hazards modeling showed a 59% reduction in risk of death for VA compared with VV ECMO (hazard reduction 0.41, 95% confidence interval: 0.18 to 0.92, p = 0.03). Patients converted from VV to VA ECMO had significantly longer survival awaiting transplant than patients who remained on VV ECMO (p = 0.03). Ambulation on ECMO before transplantation was associated with an 80% reduction in the risk of death (hazard reduction 0.20, 95% confidence interval: 0.08 to 0.48, p Conclusions Venoarterial ECMO upper body configuration for patients with end stage ILD and PH significantly improves overall survival to transplantation.

Background Frail lung transplant candidates are more likely to be delisted or die without receiving a transplant. Further knowledge of what frailty represents in this population will assist in developing interventions to prevent frailty from developing. We set out to determine whether frail lung transplant candidates have reduced exercise capacity independent of disease severity and diagnosis. Methods Sixty-eight adult lung transplant candidates underwent cardiopulmonary exercise testing (CPET) and a frailty assessment (Fried's Frailty Phenotype (FFP)). Primary outcomes were peak workload and peak aerobic capacity ( V ˙ O 2 ). We used linear regression to adjust for age, gender, diagnosis, and lung allocation score (LAS). Results The mean ± SD age was 57 ± 11 years, 51% were women, 57% had interstitial lung disease, 32% had chronic obstructive pulmonary disease, 11% had cystic fibrosis, and the mean LAS was 40.2 (range 19.2–94.5). In adjusted models, peak workload decreased by 10 W (95% CI 4.7 to 14.6) and peak V ˙ O 2 decreased by 1.8 mL/kg/min (95% CI 0.6 to 2.9) per 1 unit increment in FFP score. After adjustment, exercise tolerance was 38 W lower (95% CI 18.4 to 58.1) and peak V ˙ O 2 was 8.5 mL/kg/min lower (95% CI 3.3 to 13.7) among frail participants compared to non-frail participants. Frailty accounted for 16% of the variance (R2) of watts and 19% of the variance of V ˙ O 2 in adjusted models. Conclusion Frailty contributes to reduced exercise capacity among lung transplant candidates independent of disease severity.

Background The purpose of this work was to determine if parameters assessed during Cardiopulmonary Exercise Testing (CPET) while using supplemental oxygen can independently predict one-year transplant-free survival in patients with Interstitial Lung Disease (ILD) referred for lung transplant evaluation. Methods We performed a chart review of patients with ILD who completed CPET with 30% FiO 2 and gathered spirometry, pulmonary hemodynamic, six-minute walk, and CPET data. The primary end-point was death or lung transplantation within one-year of CPET. Results The final data set included 192 patients. 79 patients died/underwent transplant, 113 survived transplant-free. Multivariable Cox regression revealed peak workload % predicted, nadir CPET SpO 2 , and FVC% predicted as independent predictors of one-year transplant-free survival. Of the independent predictors of survival, receiver operating characteristics analysis revealed peak workload %predicted cutoff of 35% to be highly discriminatory, more so than nadir CPET SpO 2 or FVC % predicted in identifying patients at risk for one-year mortality or transplant (peak workload % predicted 2 Conclusion Peak workload % predicted, nadir CPET SpO 2 , and FVC% predicted in ILD patients referred for lung transplant evaluation are independently predictive of one-year mortality or need for transplant.

Objective Evaluate Hexoskin performance on a stationary bike against "gold standard" laboratory equipment and develop adjustment models for future use in field settings. Methods Compared respiratory rate (RR), tidal volume (VT), minute ventilation (VE), and heart rate (HR) measured by the Hexoskin shirt to simultaneous spirometry and full 12-lead electrocardiogram during a laboratory based incremental exercise test on a stationary bicycle. Results Data from 17 participants demonstrated Hexoskin VT and VE had the best agreement in the submaximal exercise level (discrepancies less than or equal to 5.3%) with larger discrepancies observed at rest (less than or equal to 15.3%) and at maximal exercise level (less than or equal to 11.7%). The discrepancies for HR and RR were lower at all levels (less than 10%). Adjusting for sex and body weight allowed for a single VE algorithm across the entire range of effort (r = 0.89). Conclusion These discrepancies are acceptable for field use in comparison to the ranges typical of bicycle commuting.

INTRODUCTION In this study we investigated non-invasive, effort-independent measurement of ventilatory mechanics in patients with amyotrophic lateral sclerosis (ALS). METHODS Ventilatory mechanics were measured by optoelectronic plethysmography (OEP) in ALS patients and matched controls. Analysis determined whether OEP measurements correlated with standard clinical measures. RESULTS ALS patients (N = 18) had lower forced vital capacity percent predicted (55.2 ± 22.0 L) compared with controls (N = 15; 104.7 ± 16.2 L) and higher ventilatory inefficiency (49.2 ± 9.0 vs. 40.0 ± 3.5, respectively; P < 0.001 for both measures). Lower tidal volumes within the diaphragm area correlated with the dyspnea subscore calculated from the ALS Functional Rating Scale-revised (P = 0.031), and paradoxical movement of the ribcage compared with the abdominal compartment was seen in the most severe cases. CONCLUSIONS Evaluation of ventilatory mechanics in mild to severe ALS reveals dysfunction that is not readily detected by standard testing and ALS functional severity assessment measures. Muscle Nerve 54: 270-276, 2016.

Real-time estimates of volumetric minute ventilation (MV) can now be made through wearable sensors, allowing field studies to extend the personal exposure approach to more accurately account for im...

Clinical exercise testing expands from field tests such as six-minute walk testing, time up and go testing, and shuttle walk testing, to lab tests such as cardiopulmonary exercise testing (CPET). Although these tests have been utilized in the clinical setting for nearly half a decade, the populations and uses for these tests are continually expanding. All of the exercise tests discussed have increased utilization in predicting postoperative outcomes; however, the six-minute walk test, timed up and go test, and shuttle walk test appear to have increased utility in populations with neurological and cognitive limitations; whereas the primary utility of CPET is in populations with cardiac and pulmonary disease.

Patients with Chronic Obstructive Pulmonary Disease (COPD) maintain the benefits of pulmonary rehabilitation (PR) longer than those with Interstitial Lung Disease (ILD). Whether this is due to physiologic differences or differences in home exercise adherence is unknown. Aims: To assess whether adherence to regular exercise after PR influences exercise performance in patients with COPD and with ILD. Methods: Data were analyzed in all patients referred for cardiopulmonary exercise testing (CPET) from 9/2016 to 1/2017. Patients with COPD or ILD who completed PR were categorized as exercise adherent (E) or non-adherent (NE) at referral. CPET performed by cycle ergometry and spirometry were measured. Multivariate regression assessed the interaction of diagnosis and exercise adherence, controlling for age and BMI, on CPET outcomes. Results: 40 patients were included (20 ILD, 20 COPD, 45% M). Exercise adherence was 55% in both groups. E had higher peak VO2 and workload than NE in both disorders. Peak ETCO2 was significantly higher in patients with NE COPD but lower in NE ILD; peak Ve/VO2 slope was significantly higher in NE ILD but lower in NE COPD. Conclusion: Alveolar hypoventilation with CPET is associated with exercise non-adherence in COPD; alveolar hyperventilation and ventilatory inefficiency with CPET are associated with exercise non-adherence in ILD. Adherence rates were the same in both disorders.

The purpose of this study was to determine the feasibility and acceptability of utilizing a smartphone based application to monitor compliance in patients with cardiac disease around discharge. For 60 days after discharge, patients’ medication compliance, physical activity, follow-up care, symptoms, and reading of education material were monitored daily with the application. 16 patients were enrolled in the study (12 males, 4 females, age 55 ± 18 years) during their hospital stay. Five participants were rehospitalized during the study and did not use the application once discharged. Seven participants completed 1–30 days and four patients completed >31 days. For those 11 patients, medication reminders were utilized 37% (1–30-day group) and 53% (>31-day group) of the time, education material was read 44% (1–30) and 53% (>31) of the time, and physical activity was reported 25% (1–30) and 42% (>31) of the time. Findings demonstrated that patients with stable health utilized the application, even if only minimally. Patients with decreased breath sounds by physical exam and who reported their health as fair to poor on the day of discharge were less likely to utilize the application. Acceptability of the application to report health status varied among the stable patients.

The purpose of this study was to compare simultaneous measurements of tidal volume (Vt) by optoelectronic plethysmography (OEP) and spirometry during a maximal cycling exercise test to quantify possible differences between methods. Vt measured simultaneously by OEP and spirometry was collected during a maximal exercise test in thirty healthy participants. The two methods were compared by linear regression and Bland-Altman analysis at submaximal and maximal exercise. The average difference between the two methods and the mean percentage discrepancy were calculated. Submaximal exercise (SM) and maximal exercise (M) Vt measured by OEP and spirometry had very good correlation, SM R=0.963 (p

In this study we investigated non-invasive, effort-independent measurement of ventilatory mechanics in patients with amyotrophic lateral sclerosis (ALS).Ventilatory mechanics were measured by optoelectronic plethysmography (OEP) in ALS patients and matched controls. Analysis determined whether OEP measurements correlated with standard clinical measures.ALS patients (N = 18) had lower forced vital capacity percent predicted (55.2 ± 22.0 L) compared with controls (N = 15; 104.7 ± 16.2 L) and higher ventilatory inefficiency (49.2 ± 9.0 vs. 40.0 ± 3.5, respectively; P0.001 for both measures). Lower tidal volumes within the diaphragm area correlated with the dyspnea subscore calculated from the ALS Functional Rating Scale-revised (P = 0.031), and paradoxical movement of the ribcage compared with the abdominal compartment was seen in the most severe cases.Evaluation of ventilatory mechanics in mild to severe ALS reveals dysfunction that is not readily detected by standard testing and ALS functional severity assessment measures. Muscle Nerve 54: 270-276, 2016.

New advances in computer processing and imaging have allowed the development of innovative techniques to assess lung function. A promising methodology is optoelectronic plethysmography (OEP). OEP evaluates ventilatory kinematics through the use of infrared imaging. Markers are placed, and images read on the chest, back and abdomen of subjects. Currently, this system is used mainly in research settings, but in the future may have broad applicability to patient populations such as very young children, patients with neuromuscular disease and patients who cannot be tested with classical spirometry testing. This paper presents the history and development of OEP, along with a summary of the OEP methodology, a discussion of research findings and results to date, as well as application and limitations.

To determine the effects of central chemoreceptor stimulation upon sympathetic modulation while minimizing baroreceptor influences, we performed a single-blind, counter-balanced, placebo-controlled trial of a modified hypercapnic/hyperoxic rebreathe protocol stimulus to activate the central chemoreflex. Muscle sympathetic nerve activity (MSNA), heart rate, blood pressure, and ventilation were recorded dynamically as subjects transitioned from a hypocapnia to hypercapnia state. The stages of data recording were defined as hyperventilation (HyV), pre-threshold (PreT) and post-threshold (PostT), with threshold being defined as the point of non-linear deviation in ventilation. The changes in MSNA (−4.2 ± 52.4 arbitrary units (AU) vs. 245.0 ± 84.0 AU) and burst count (−0.1 ± 0.7 bursts/segment vs. 2.5 ± 1.7 bursts/segment) were significantly different between control and rebreathe for the HyV to PreT step. There was also a significant difference for PreT to PostT for total MSNA (3.9 ± 65.4 AU vs. 183.7 ± 104.2 AU). In a hypercapnic/hyperoxic state, the central chemoreceptors modulate sympathetic activity below the chemoreflex threshold independently of the baroreceptors, possibly contributing to basal autonomic/sympathetic tone. Central chemoreceptors also appear to play a significant role in sympathetic modulation after the threshold.

Rationale: This study quantitatively measured the effects of lung volume reduction surgery (LVRS) on spirometry, static and dynamic lung and chest wall volume subdivision mechanics, and cardiopulmonary exercise measures. Methods: Patients with severe COPD (mean FEV1 = 23 ± 6% predicted) undergoing LVRS evaluation were recruited. Spirometry, plethysmography and exercise capacity were obtained within 6 months pre-LVRS and again within 12 months post- LVRS. Ventilatory mechanics were quantified using stationary optoelectronic plethysmography (OEP) during spontaneous tidal breathing and during maximum voluntary ventilation (MVV). Statistical significance was set at P< 0.05. Results:Ten consecutive patients met criteria for LVRS (5 females, 5 males, age: 62±6yrs). Post -LVRS (mean follow up 7 months ± 2 months), the group showed significant improvements in dyspnea scores (pre 4±1 versus post 2 ± 2), peak exercise workload (pre 37± 21 watts versus post 50 ± 27watts ), heart rate (pre 109±19 beats per minutes [bpm] versus post 118±19 bpm), duty cycle (pre 30.8 ± 3.8% versus post 38.0 ± 5.7%), and spirometric measurements (forced expiratory volume in 1 second [FEV1] pre 23 ± 6% versus post 32 ± 13%, total lung capacity / residual lung volume pre 50 ± 8 versus 50 ± 11) . Six to 12 month changes in OEP measurements were observed in an increased percent contribution of the abdomen compartment during tidal breathing (41.2±6.2% versus 44.3±8.9%, P=0.03) and in percent contribution of the pulmonary ribcage compartment during MVV (34.5±10.3 versus 44.9±11.1%, P=0.02). Significant improvements in dynamic hyperinflation during MVV occurred, demonstrated by decreases rather than increases in end expiratory volume (EEV) in the pulmonary ribcage (pre 207.0 ± 288.2 ml versus post -85.0 ± 255.9 ml) and abdominal ribcage compartments (pre 229.1 ± 182.4 ml versus post -17.0 ± 136.2 ml) during the maneuver. Conclusions: Post-LVRS, patients with severe COPD demonstrate significant favorable changes in ventilatory mechanics, during tidal and maximal voluntary breathing. Future work is necessary to determine if these findings are clinically relevant, and extend to other environments such as exercise.

To determine how increased ventilatory demand impacts ventilatory kinematics, we compared the total chest wall volume variations (V(CW)) of male and female endurance-trained athletes (ET) to untrained individuals (UT) during exercise. We hypothesized that training and gender would have an effect on V(CW) and kinematics at maximal exercise. Gender and training significantly influenced chest wall kinematics. Female ET did not change chest wall end-expiratory volume (V(CW,ee)) or pulmonary ribcage (V(RCp,ee)) with exercise, while female UT significantly decreased V(CW,ee) and V(RCp,ee) with exercise (p0.05). Female ET significantly increased pulmonary ribcage end-inspiratory volume (V(RCp,ei)) with exercise (p0.05), while female UT did not change V(RCp,ei) with exercise. Male ET significantly increased V(RCp,ei) with exercise (p0.05); male UT did not. Men and women had significantly different variation of V(CW) (p0.05). Women demonstrated the greatest variation of V(CW) in the pulmonary ribcage compartment (V(RCp)). Men had even volumes variation of the V(RCp) and the abdomen (V(Ab)). In conclusion, gender and training had a significant impact on ventilatory kinematics.