Cardiac output measurement during exercise in COPD: A comparison of dye dilution and impedance cardiography

Louvaris, Zafeiris; Spetsioti, Stavroula; Andrianopoulos, Vasileios; Chynkiamis, Nikolaos; Habazettl, Helmut; Wagner, Harrieth; Zakynthinos, Spyros; Wagner, Peter D.; Vogiatzis, Ioannis

doi:10.1111/crj.13002

Cited by 31 publications

(40 citation statements)

References 27 publications

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“…Using non‐invasive and validated (for patients with COPD) technologies (impedance cardiography and NIRS) (Louvaris et al . 2018, 2019), we examined the response of various physiological systems during exercise to the limit of tolerance. Our work provides the physiological rationale for the implementation of IE alternating maximal intensity work periods with periods of moderate exercise loads, maintaining reduced dynamic hyperinflation and breathing discomfort and extending endurance time compared with CLE at the same average power output.…”

Section: Discussionmentioning

confidence: 99%

“…Cardiac output was measured non‐invasively and essentially continuously during the IE and CLE protocols by transthoracic impedance (PhysioFlow PF05; Manatec Biomedical, Macheren, France, PhysioFlow) validated for patients with COPD over a wide range of exercise intensities including peak exercise (Louvaris et al . 2019). Six electrodes (PhysioFlow PF5; Manatec Biomedical, Macheren, France) in total were placed according to the manufacturer's instructions: two on the neck on the left side (one vertically above the other over the carotid artery above the supraclavicular fossa); two anteriorly in the xiphoid region; and two in locations corresponding to the V1 and V6 positions used for conventional ECG monitoring as were previously described (Louvaris et al .…”

Section: Methodsmentioning

confidence: 99%

“…Six electrodes (PhysioFlow PF5; Manatec Biomedical, Macheren, France) in total were placed according to the manufacturer's instructions: two on the neck on the left side (one vertically above the other over the carotid artery above the supraclavicular fossa); two anteriorly in the xiphoid region; and two in locations corresponding to the V1 and V6 positions used for conventional ECG monitoring as were previously described (Louvaris et al . 2019). To optimize the impedance signal a careful skin preparation was performed.…”

Section: Methodsmentioning

confidence: 99%

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Greater exercise tolerance in COPD during acute interval, compared to equivalent constant‐load, cycle exercise: physiological mechanisms

Louvaris

Chynkiamis

Spetsioti

et al. 2020

The Journal of Physiology

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Key points Exercise intolerance is common in chronic obstructive pulmonary disease (COPD) patients. In patients with COPD, we compared an interval exercise (IE) protocol (alternating 30 s at 100% peak work rate (WRpeak) with 30 s at 50% WRpeak) with moderate‐intensity constant‐load exercise (CLE) at 75% WRpeak, which yielded the same work rate. Exercise endurance time and total work output were almost twice as high for IE than CLE. At exercise isotime (when work completed was the same between IE and CLE), IE was associated with less dynamic hyperinflation, lower blood lactate concentration, and greater respiratory and locomotor muscle oxygenation, but there were no differences in ventilation or cardiac output. However, at the limit of tolerance for each modality, dynamic hyperinflation was not different between IE and CLE, while blood lactate remained lower and muscle oxygenation higher with IE. Taken together, these findings suggest that dynamic hyperinflation and not muscle‐based factors dictate the limits of tolerance in these COPD patients. Abstract The relative importance of ventilatory, circulatory and peripheral muscle factors in determining tolerance to exercise in patients with chronic obstructive pulmonary disease (COPD) is not known. In 12 COPD patients (forced expiratory volume in one second: 58 ± 17%pred.) we measured ventilation, cardiac output, dynamic hyperinflation, local muscle oxygenation, blood lactate and time to exhaustion during (a) interval exercise (IE) consisting of 30 s at 100% peak work rate alternating with 30 s at 50%, and (b) constant‐load exercise (CLE) at 75% peak work rate, designed to produce the same average work rate. Exercise time was substantially longer during IE than CLE (19.5 ± 4.8 versus 11.4 ± 2.1 min, p = 0.0001). Total work output was therefore greater during IE than CLE (81.3 ± 27.7 versus 48.9 ± 23.8 kJ, p = 0.0001). Dynamic hyperinflation (assessed by changes from baseline in inspiratory capacity, ΔIC) was less during IE than CLE at CLE exhaustion time (isotime, p = 0.009), but was similar at exhaustion (ΔICCLE: ‐0.38 ± 0.10 versus ΔICIE: ‐0.33 ± 0.12 l, p = 0.102). In contrast, at isotime, minute ventilation, cardiac output and systemic oxygen delivery did not differ between protocols (P > 0.05). At exhaustion in both protocols, the vastus lateralis and intercostal muscle oxygen saturation were higher in IE than CLE (p = 0.014 and p = 0.0002, respectively) and blood lactate concentrations were lower (4.9 ± 2.4 mmol l‐1 versus 6.4 ± 2.2 mmol l‐1, p = 0.039). These results suggest that (1) exercise tolerance with COPD is limited by dynamic hyperinflation; and (2) cyclically lower (50%) effort intervals in IE help to preserve muscle oxygenation and reduce metabolic acidosis compared with CLE at the same average work rate; but these factors do not appear to determine time to exhaustion.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Greater exercise tolerance in COPD during acute interval, compared to equivalent constant‐load, cycle exercise: physiological mechanisms

Louvaris

Chynkiamis

Spetsioti

et al. 2020

The Journal of Physiology

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“…In this single-center study changes were analyzed in the hemodynamic profile of AMI patients by using ICG. Although a good correlation between impedance diagnostics and invasive assessment of cardiac output and systemic vascular resistance has been reported [10,11], thus far, data is mostly limited to heart failure [12][13][14][15][16][17][18][19] and with only a few AMI subsets examined [20][21][22].…”

Section: Discussionmentioning

confidence: 99%

“…Louvaris et al [11] compared concurrent CO measurements captured by ICG (CO IC ) and by the indocyanine green dye dilution method (CO DD ) in patients with chronic obstructive pulmonary disease. They found a strong correlation between CO IC and CO DD .…”

Section: Introductionmentioning

confidence: 99%

The non-invasive evaluation of heart function in patients with an acute myocardial infarction: The role of impedance cardiography

Lewicki¹,

Fijałkowska²,

Karwowski³

et al. 2021

Cardiol J.

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Background: The purpose of this study was to analyze hemodynamic changes in patients treated with percutaneous coronary intervention (PCI) at an early stage of acute myocardial infarction (AMI) and at 1-month follow-up. Methods: Patients with AMI (n = 27) who underwent PCI were analyzed using impedance cardiography (ICG). ICG data were collected continuously (beat by beat) during the whole PCI procedure and thereafter at every 60 s for the next 24 h. Blood pressure was taken every 10 min and stored for analysis. Additionally the following parameters were measured: cardiac index (CI), stroke volume index (SVi), left cardiac work index (LCWi), contractility index (CTi), ventricular ejection time (VET), systemic vascular resistance index (SVRi), thoracic fluid content index (TFCi) and heart rate (HR). Results: In the first 24 h after PCI all the contractility parameters including CI, SVi, LCWi, CTi and VET significantly decreased, whereas HR, SVRi and TFCi increased compared to baseline. All of the parameters examined got normalized at 1 month. The CI, SVi, LCWi, CTi, SVRi did not significantly differ from baseline, however the HR and VET were significantly lower compared to first day after PCI. Conclusions: Cardiac performance deteriorates early after PCI and normalizes after 1 month in patients with an AMI. ICG is useful for hemodynamic monitoring of AMI patients during and after invasive therapy.

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Ergogenic value of oxygen supplementation in chronic obstructive pulmonary disease

2022

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Patients with COPD exhibit limited exercise endurance time compared to healthy age-matched individuals. Oxygen supplementation is often applied to improve endurance time during pulmonary rehabilitation in patients with COPD and thus a comprehensive understanding of the mechanisms leading to improved endurance is desirable. This review analyses data from two studies by our research group investigating the effect of oxygen supplementation on cerebrovascular, systemic, respiratory and locomotor muscle oxygen availability on the same cohort of individuals with advanced COPD, and the mechanisms associated with improved endurance time in hyperoxia, which was essentially doubled (at the same power output). In hyperoxia at isotime (the time at which patients became exhausted in normoxia) exercise was associated with greater respiratory and locomotor muscle (but not frontal cortex) oxygen delivery (despite lower cardiac output), lower lactate concentration and less tachypnoea. Frontal cortex oxygen saturation was higher, and respiratory drive lower. Hence, improved endurance in hyperoxia appears to be facilitated by several factors: increased oxygen availability to the respiratory and locomotor muscles, less metabolic acidosis, and lower respiratory drive. At exhaustion in both normoxia and hyperoxia, only cardiac output and breathing pattern were not different between conditions. However, minute ventilation in hyperoxia exceeded the critical level of ventilatory constraints (VE/MVV > 75–80%). Lactate remained lower and respiratory and locomotor muscle oxygen delivery greater in hyperoxia, suggesting greater muscle oxygen availability improving muscle function. Taken together, these findings suggest that central haemodynamic and ventilatory limitations and not contracting muscle conditions dictate endurance time in COPD during exercise in hyperoxia.

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Cardiac output measurement during exercise in COPD: A comparison of dye dilution and impedance cardiography

Cited by 31 publications

References 27 publications

Greater exercise tolerance in COPD during acute interval, compared to equivalent constant‐load, cycle exercise: physiological mechanisms

Greater exercise tolerance in COPD during acute interval, compared to equivalent constant‐load, cycle exercise: physiological mechanisms

The non-invasive evaluation of heart function in patients with an acute myocardial infarction: The role of impedance cardiography

Ergogenic value of oxygen supplementation in chronic obstructive pulmonary disease

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