Ascha M; Bhattacharyya A; Ramos JA; Tonelli AR.

Medicine & Science in Sports & Exercise. 50(10):1992-1997, 2018 Oct.
VI 1

INTRODUCTION/PURPOSE: Peripheral capillary oxygen saturation (SpO2) is
used as surrogate for arterial blood oxygen saturation. We studied the
degree of discrepancy between SpO2 and arterial oxygen (SaO2) and
identified parameters that may explain this difference.
METHODS: We included patients who underwent cardiopulmonary exercise
testing at Cleveland Clinic. Pulse oximeters with forehead probes measured
SpO2 and arterial blood gas samples provided the SaO2 both at rest and
peak exercise.
RESULTS: We included 751 patients, 54 +/- 16 yr old with 53% of female
gender. Bland-Altman analysis revealed a bias of 3.8% with limits of
agreement of 0.3% to 7.9% between SpO2 and SaO2 at rest. A total of 174
(23%) patients had SpO2 >= 5% of SaO2, and these individuals were older,
current smokers with lower forced expiratory volume in the first second
and higher partial pressure of carbon dioxide and carboxyhemoglobin. At
peak exercise (n = 631), 75 (12%) SpO2 values were lower than the SaO2
determinations reflecting difficulties in the SpO2 measurement in some
patients. The bias between SpO2 and SaO2 was 2.6% with limits of agreement
between -2.9% and 8.1%. Values of SpO2 >= 5% of SaO2 (n = 78, 12%) were
associated with the significant resting variables plus lower heart rate,
oxygen consumption, and oxygen pulse. In multivariate analyses,
carboxyhemoglobin remained significantly associated with the difference
between SpO2 and SaO2 both at rest and peak exercise.
CONCLUSIONS: In the present study, pulse oximetry commonly overestimated
the SaO2. Increased carboxyhemoglobin levels are independently associated
with the difference between SpO2 and SaO2, a finding particularly relevant
in smokers.

Wagner J; Agostoni P; Arena R; Belardinelli R; Dumitrescu D; Hager A;
Myers J; Rauramaa R; Riley M; Takken T; Schmidt-Trucksass A.

American Heart Journal. 202:116-126, 2018 08.
VI 1

Heart failure with reduced ejection fraction (HFrEF) is common in the
developed world and results in significant morbidity and mortality.
Accurate risk assessment methods and prognostic variables are therefore
needed to guide clinical decision making for medical therapy and surgical
interventions with the ultimate goal of decreasing risk and improving
health outcomes. The purpose of this review is to examine the role of
cardiopulmonary exercise testing (CPET) and its most commonly used
ventilatory gas exchange variables for the purpose of risk stratification
and management of HFrEF. We evaluated five widely studied gas exchange
variables from CPET in HFrEF patients based on nine previously used
systematic criteria for biomarkers. This paper provides clinicians with a
comprehensive and critical overview, class recommendations and evidence
levels. Although some CPET variables met more criteria than others,
evidence supporting the clinical assessment of variables beyond peak VO2
is well-established. A multi-variable approach also including the VE-VCO2
slope and EOV is therefore recommended.

DeCato TW; Bradley SM; Wilson EL; Harlan NP; Villela MA; Weaver LK; Hegewald MJ;

Undersea & Hyperbaric Medicine: Journal Of The Undersea And Hyperbaric Medical Society, Inc [Undersea Hyperb Med] 2019 Mar-Apr-May; Vol. 46, pp. 117-124.

Objectives: Hyperbaric oxygen (HBO2) exposure may enhance cardiorespiratory fitness. Exercise training and HBO2 exposure stimulate mitochondrial biogenesis, increase capillary density, and induce adaptive antioxidant mechanisms. We hypothesized that an exercise regimen of sprint interval training (SIT) while breathing HBO2 would lead to a greater improvement in exercise performance compared to the same training breathing ambient air.
Methods: Healthy long-term intermediate-altitude residents, ages 20-39 years, with normal spirometry and cardiorespiratory fitness were randomized to two groups: one performing six sessions of a SIT regimen over two weeks in a hyperbaric chamber (1.4 ATA [141.9 kPa], FiO2=1.0); the other performing under ambient pressure conditions (0.85 ATA [86.1 kPa], FiO2=0.21). Training effect was evaluated by comparing incremental cycle ergometry cardiopulmonary exercise testing before and after the training regimen. The primary outcome measure was peak oxygen consumption (V̇O2), while secondary outcomes included additional exercise parameters. The effect of study group on exercise parameters was assessed using two-factor repeated measures ANOVA.
Results: Of 58 participants randomized, 49 completed the training program and all cardiopulmonary exercise tests (n=23 HBO2, n=26 ambient). Both groups experienced an increase in peak V̇O2: 8.1% HBO2 and 7.1% ambient; the differences were not significant (p=0.50). Secondary parameters of peak work rate and peak V̇E experienced a significantly higher change in the HBO2 group compared to the ambient group (p=0.05 and p=0.03, respectively).
Conclusion: Cardiorespiratory fitness improved after a two-week SIT regimen, but improvement in peak V̇O2 was not significantly different between ambient and HBO2 groups.

Vukomanovic V; Suzic-Lazic J; Celic V; Cuspidi C; Petrovic T;Grassi G; Tadic M;

Journal Of Hypertension [J Hypertens] 2019 Apr 29. Date of Electronic Publication: 2019 Apr 29.

Objective: We aimed to evaluate the association between functional capacity and left ventricular (LV) mechanics in the patients with uncomplicated type 2 diabetes.
Methods: The present cross-sectional study included 80 controls and 70 uncomplicated diabetic patients. These participants underwent laboratory analysis, comprehensive echocardiographic examination and cardiopulmonary exercise testing.
Results: Global longitudinal (-21.6 ± 2.8 vs. -18.4 ± 2.3%, P < 0.001) and circumferential (-22.0 ± 2.9 vs. -19.5 ± 2.6%, P < 0.001) strains were significantly reduced in diabetic participants. The same was found for longitudinal and circumferential endocardial, mid-myocardial and epicardial strains. Peak oxygen uptake (27.0 ± 4.3 vs. 20.7 ± 4.0 ml/kg/min, P < 0.001) and oxygen pulse (14.1 ± 3.0 vs. 11.6 ± 3.2 ml/beat, P < 0.001) were significantly lower in the diabetic group, while ventilation/carbon dioxide slope was significantly higher in these patients. In the whole study population glycosylated hemoglobin, as well as LV endocardial longitudinal and circumferential strains were independently of other clinical and echocardiographic parameters of LV structure, systolic and diastolic function associated with peak oxygen consumption and oxygen pulse.
Conclusion: Our investigation showed that diabetes equally affected all LV myocardial layers. Endocardial LV longitudinal and circumferential strains, as well as glycosylated hemoglobin – main parameter of glucose regulation, were independently associated with functional capacity in the whole study population. These findings indicate that determination of LV strain and functional capacity could detect subclinical target organ damage and prevent development of further complications in uncomplicated diabetes mellitus patients.

Roberts TJ; Burns AT; MacIsaac RJ; MacIsaac AI; Prior DL; La Gerche A;

Journal Of Applied Physiology (Bethesda, Md.: 1985) [J Appl Physiol (1985)] 2019 May 02. Date of Electronic Publication: 2019 May 02.

Exercise capacity is frequently reduced in people with diabetes mellitus (DM) and the contribution of pulmonary microvascular dysfunction remains undefined. We hypothesized that pulmonary microvascular disease, measured by a novel exercise echocardiography technique termed pulmonary transit of agitated contrast (PTAC), would be greater in subjects with DM, and that the use of pulmonary vasodilator agent sildenafil would improve exercise performance by reducing right ventricular afterload. Forty subjects with DM and 20 matched controls performed cardiopulmonary exercise testing and semi-supine exercise echocardiography one hour after placebo or sildenafil ingestion in a double-blind randomized cross-over design. The primary efficacy end-point was exercise capacity (VO2peak) whilst secondary measures included pulmonary vascular resistance, cardiac output and change in PTAC. DM subjects were aged 44 ± 13 years, 73% male, with 16 ± 10 years’ DM history. Sildenafil caused marginal improvements in echocardiographic measures of biventricular systolic function in DM subjects. Exercise-induced increases in pulmonary artery systolic pressure and pulmonary vascular resistance were attenuated with sildenafil, while heart rate (+2.4 ±1.2bpm P=0.04) and cardiac output (+322 ±21 ml, P=0.03) improved. However, the degree of PTAC did not change (P=0.93) and VO2max did not increase following sildenafil as compared to placebo (VO2peak 31.8 ±9.7 vs. 32.1 ±9.5 ml/min/kg, P=0.42). We conclude that sildenafil administration causes modest acute improvements in central hemodynamics but does not improve exercise capacity. This may be due to the mismatch in action of sildenafil on the pulmonary arteries rather than the distal pulmonary microvasculature and potential adverse effects on peripheral oxygen extraction.

Agostoni P; Dumitrescu D;

International Journal Of Cardiology [Int J Cardiol] 2019 Apr 18. Date of Electronic Publication: 2019 Apr 18.

In the present practice review, we will explain how to perform and interpret a cardiopulmonary exercise test (CPET) in heart failure patients. Specifically, we will explain why cycle ergometer should be preferred to treadmill, the type of protocol needed, and the ideal exercise duration. Thereafter, we will discuss how to interpret CPET findings and determine the parameters that should be included. We will focus specifically on: peak VO2 (absolute value and a percentage of its predicted value), exercise duration, respiratory exchange ratio, peak work rate, heart rate, O2 pulse, end-tidal carbon dioxide pressure (PetCO2), PetO2, and -if blood gas samples are obtained-dead space to tidal volume ratio. Moreover, we will discuss the physiological and clinical value of anaerobic threshold, respiratory compensation point, ventilation vs. VCO2 and VO2 vs. work relationships. Finally, attention will be dedicated to exercise-induced periodic breathing. We will also discuss when and why CPET should be integrated with other measurements in the so-called complex CPET. Specifically: a) when and how to use a complex non-invasive CPET, which integrates CPET measurements with non-invasive cardiac output determination, working muscle near-infrared spectroscopy, transthoracic echocardiography, thoracic ultrasound, and lung diffusion analysis; b) when and how to use a complex minimally invasive CPET, in which CPET is combined with esophageal balloon recordings or with serial arterial blood sampling for blood gas analysis; c) when and how to use a complex invasive CPET, which usually implies the presence of a Swan Ganz catheter in the pulmonary artery and an arterial line.

Kneis S; Wehrle A;Müller J;Maurer C; Ihorst G; Gollhofer A; Bertz H;

BMC Cancer [BMC Cancer] 2019 May 02; Vol. 19 (1), pp. 414. Date of Electronic Publication: 2019 May 02.Publication Type:

Background: Chemotherapy-induced peripheral neuropathy (CIPN) can affect functional performance and quality of life considerably. Since balance training has proven to enhance physical function, it might be a promising strategy to manage CIPN-induced functional impairments.
Methods: Fifty cancer survivors with persisting CIPN after finishing their treatment were randomly allocated to an intervention (IG) or active control group (CG). The IG did endurance plus balance training, the CG only endurance training (twice weekly over 12 weeks). Pre- and post-assessments included functional performance, cardiorespiratory fitness, vibration sense, and self-reported CIPN symptoms (EORTC QLQ-CIPN20).
Results: Intention-to-treat analyses (n = 41) did not reveal a significant group difference (CG minus IG) for sway path in semi-tandem stance after intervention (primary endpoint), adjusted for baseline. However, our per-protocol analysis of 37 patients with training compliance ≥70% revealed: the IG reduced their sway path during semi-tandem stance (- 76 mm, 95% CI -141 – -17; CG: -6 mm, 95% CI -52 – 50), improved the duration standing on one leg on instable surface (11 s, 95% CI 8-17; CG: 0 s, 95%CI 0-5) and reported decreased motor symptoms (-8points, 95% CI -18 – 0; CG: -2points 95% CI -6 – 2). Both groups reported reduced overall- (IG: -10points, 95% CI -17 – -4; CG: -6points, 95% CI -11 – -1) and sensory symptoms (IG: -7points, 95% CI -15 – 0; CG: -7points, 95% CI -15 – 0), while only the CG exhibited objectively better vibration sense (knuckle: 0.8points, 95% CI 0.3-1.3; IG: 0.0points, 95% CI -1.1 – 0.9; patella: 1.0points, 95% CI 0.4-1.6: IG: -0.8points, 95% CI -0.2 – 0.0). Furthermore, maximum power output during cardiopulmonary exercise test increased in both groups (IG and CG: 0.1 W/kg, 95% CI 0.0-0.2), but only the CG improved their jump height (2 cm, 95% CI 0.5-3.5; IG: 1 cm, 95% CI -0.4 – 3.2).
Conclusion: We suppose that endurance training induced a reduction in sensory symptoms in both groups, while balance training additionally improved patients’ functional status. This additional functional effect might reflect the IG’s superiority in the CIPN20 motor score. Both exercises provide a clear and relevant benefit for patients with CIPN.

Boutou AK; Pitsiou G; Panagiotidou E; Stanopoulos I;

The Clinical Respiratory Journal [Clin Respir J] 2019 May 03. Date of Electronic Publication: 2019 May 03.

We read with interest the paper of Jiang R et al regarding cardiopulmonary exercise responses among patients with borderline mean pulmonary artery pressure (boPAP) [1]. Previous data indicate that patients with mean pulmonary artery pressure (mPAP) levels between 21-24 mm Hg may consist a high-risk group that should be closely monitored, since they present with functional impairment [2] and increased mortality [2, 3], compared to those without pulmonary hypertension (PH), while a significant proportion of these subjects develop overt PH during follow-up [3]. However, data on specific exercise characteristics which may consist a distinct cardiopulmonary exercise testing (CPET) pattern which could discriminate patients with boPAP from those with or without PH, are currently scarce. Under this scope, the study of Jiang R et al [1] adds novel information to this direction.

Stöcker F; Neidenbach R; Fritz C; Oberhoffer RM; Ewert P; Hager A; Nagdyman N;

Frontiers In Pediatrics [Front Pediatr] 2019 Mar 26; Vol. 7, pp. 96. Date of Electronic Publication: 20190326 (Print Publication: 2019).

Introduction: As survival of previously considered as lethal congenital heart disease forms is the case in our days, issues regarding quality of life including sport and daily activities emerge. In patients with Fontan circulation, there is no pump to propel blood into the pulmonary arteries since the systemic veins are directly connected to the pulmonary arteries. The complex hemodynamics of Fontan circulation include atrial function, peripheral muscle pump, integrity of the atrioventricular valve, absence of restrictive, or obstructive pulmonary lung function. Therefore, thoracic mechanics are of particular importance within the complex hemodynamics of Fontan circulation.
Methods: To understand the physiology of respiratory muscles, the aim of this study was to examine the matching of auxiliary respiratory muscle oxygen delivery and utilization during incremental exercise in young male Fontan patients (n = 22, age = 12.04 ± 2.51) and healthy Controls (n = 10, age = 14.90 ± 2.23). All subjects underwent a cardiopulmonary exercise test (CPET) to exhaustion whereas respiratory muscle oxygenation was measured non-invasively using a near-infrared spectrometer (NIRS).
Results: CPET revealed significantly lower peak power output, oxygen uptake and breath activity in Fontan patients. The onset of respiratory muscle deoxygenation was significantly earlier. The matching of local muscle perfusion to oxygen demand was significantly worse in Fontans between 50 and 90% [Formula: see text] .
Findings: The results indicate that (a) there is high strain on respiratory muscles during incremental cycling exercise and (b) auxiliary respiratory muscles are worse perfused in patients who underwent a Fontan procedure compared to healthy Controls. This might be indicative of a more general skeletal muscle strain and worse perfusion in Fontan patients rather than a localized-limited to thoracic muscles phenomenon.

Mylius CF; Krijnen WP; van der Schans CP; Takken T;

ERJ Open Research [ERJ Open Res] 2019 Apr 01; Vol. 5 (2). Date of Electronic Publication: 20190401 (Print Publication: 2019).

Peak oxygen uptake (V’O2peak) is recognised as the best expression of aerobic fitness. Therefore, it is essential that V’O2peak reference values are accurate for interpreting a cardiopulmonary exercise test (CPET). These values are country specific and influenced by underlying biological ageing processes. They are normally stratified per paediatric and adult population, resulting in a discontinuity at the transition point between prediction equations. There are currently no age-related reference values available for the lifespan of individuals in the Dutch population. The aim of this study is to determine the best-fitting regression model for V’O2peak in the healthy Dutch paediatric and adult populations in relation to age. In this retrospective study, CPET cycle ergometry results of 4477 subjects without reported somatic diseases were included (907 females, age 7.9-65.0 years). Generalised additive models were employed to determine the best-fitting regression model. Cross-validation was performed against an independent dataset consisting of 3518 subjects (170 females, age 6.8-59.0 years). An additive model was the best fitting with the largest predictive accuracy in both the primary (adjusted R2=0.57, standard error of the estimate (see)=556.50 mL·min-1) and cross-validation (adjusted R2=0.57, see=473.15 mL·min-1) dataset. This study provides a robust additive regression model for V’O2peak in the Dutch population.