doppler-ultrasound-based-leg-blood-flow-assessment-during-single-leg

Doppler Ultrasound-Based Leg Blood Flow Assessment During Single-Leg Knee-Extensor Exercise in an Uncontrolled Setting

Doppler ultrasound has revolutionized the assessment of organ blood flow and is widely used in research and clinical settings. While Doppler ...

dual-test-gas-pulmonary-diffusing-capacity-measurement-during

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method

The combined single-breath measurement of the diffusing capacity of carbon monoxide (DL,CO) and nitric oxide (DL,NO) is a useful technique to measure ...

Copenhagen University Hospital

Copenhagen University Hospital, Hvidovre Hospital

Copenhagen University Hospital - Rigshospitalet

Hvidovre Hospital

Disease-related under-nutrition is a common problem in individuals with COPD. The rationale for nutritional support in pulmonary rehabilitation therefore seems obvious. However there is limited evidence regarding the patient-relevant outcomes i.e. activities of daily living (ADL) or quality of life. Therefore the topic was included in The Danish Health and Medicines Authority's development of an evidence-based clinical guideline for rehabilitation of patients with stable COPD.

Danish evidence-based clinical guideline for use of nutritional support in pulmonary rehabilitation of undernourished patients with stable COPD.

Cardiorespiratory fitness is positively related to heart failure (HF) prognosis, but lack of time and low energy are barriers for adherence to exercise. We, therefore, compared the effect of low-volume time-based resistance exercise training (TRE) with aerobic moderate-intensity cycling (AMC) on maximal and submaximal exercise capacity, health-related quality of life, and vascular function.

Comparative Effectiveness of Low-Volume Time-Efficient Resistance Training Versus Endurance Training in Patients With Heart Failure.

Pulmonary rehabilitation (PR), delivered as a supervised multidisciplinary program including exercise training, is one of the cornerstones in the chronic obstructive pulmonary disease (COPD) management. We performed a systematic review and meta-analysis to assess the effect on mortality of a supervised early PR program, initiated during or within 4 weeks after hospitalization with an acute exacerbation of COPD compared with usual post-exacerbation care or no PR program. Secondary outcomes were days in hospital, COPD related readmissions, health-related quality of life (HRQoL), exercise capacity (walking distance), activities of daily living (ADL), fall risk and drop-out rate.

Lower mortality after early supervised pulmonary rehabilitation following COPD-exacerbations: a systematic review and meta-analysis.

What is the topic of this review? Lactate is considered an important substrate for mitochondria in the muscles, heart and brain during exercise and is the main gluconeogenetic precursor in the liver and kidneys. In this light, we review the (patho)physiology of lactate metabolism in sepsis and coronavirus disease 2019 (COVID-19). What advances does it highlight? Elevated blood lactate is strongly associated with mortality in septic patients. Lactate seems unrelated to tissue hypoxia but is likely to reflect mitochondrial dysfunction and high adrenergic stimulation. Patients with severe COVID-19 exhibit near-normal blood lactate, indicating preserved mitochondrial function, despite a systemic hyperinflammatory state similar to sepsis.

The role of lactate in sepsis and COVID-19: Perspective from contracting skeletal muscle metabolism.

What is the topic of this review? The use of proning for improving pulmonary gas exchange in critically ill patients. What advances does it highlight? Proning places the lung in its 'natural' posture, and thus optimises the ventilation-perfusion distribution, which enables lung protective ventilation and the alleviation of potentially life-threatening hypoxaemia in COVID-19 and other types of critical illness with respiratory failure.

Therapeutic benefits of proning to improve pulmonary gas exchange in severe respiratory failure: focus on fundamentals of physiology.

 Skeletal muscle convective and diffusive oxygen (O) transport are peripheral determinants of exercise capacity in both patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). We hypothesised that differences in these peripheral determinants of performance between COPD and CHF patients are revealed during small muscle mass exercise, where the cardiorespiratory limitations to exercise are diminished.  Eight patients with moderate to severe COPD, eight patients with CHF (NYHA II), and eight age- and sex-matched controls were studied. We measured leg blood flow (Q̇) by Doppler ultrasound during submaximal one-legged knee-extensor exercise (KEE), while sampling arterio-venous variables across the leg. The capillary oxyhaemoglobin dissociation curve was reconstructed from paired femoral arterial-venous oxygen tensions and saturations, which enabled the estimation of O parameters at the microvascular level within skeletal muscle, so that skeletal muscle oxygen conductance (DO) could be calculated and adjusted for flow (DO/Q̇) to distinguish convective from diffusive oxygen transport.  During KEE, Q̇ increased to a similar extent in CHF (2.0 (0.4) L/min) and controls (2.3 (0.3) L/min), but less in COPD patients (1.8 (0.3) L/min) ( <0.03). There was no difference in resting DO between COPD and CHF and when adjusting for flow, the DO was higher in both groups compared to controls (COPD: 0.97 (0.23) vs. controls 0.63 (0.24) mM/kPa, = 0.02; CHF 0.98 (0.11) mM/kPa vs. controls, = 0.001). The Q̇-adjusted DO was not different in COPD and CHF during KEE (COPD: 1.19 (0.11) vs. CHF: 1.00 (0.18) mM/kPa; = 0.24) but higher in COPD vs. controls: 0.87 (0.28) mM/kPa (= 0.02), and only CHF did not increase Q̇-adjusted DO from rest (= 0.2).  Disease-specific factors may play a role in peripheral exercise limitation in patients with COPD compared with CHF. Thus, low convective O transport to contracting muscle seemed to predominate in COPD, whereas muscle diffusive O transport was unresponsive in CHF.

Regulation of the microvasculature during small muscle mass exercise in chronic obstructive pulmonary disease vs. chronic heart failure.

What is the central question in this study? How reliable is the combined measurement of the pulmonary diffusing capacity to carbon monoxide and nitric oxide (D ) during exercise and in the resting supine position, respectively? What is the main finding and its importance? The D technique is reliable with a very low day-to-day variability both during exercise and in the resting supine position, and may thus provide a useful physiological outcome that reflects the alveolar-capillary reserve in humans.

Pulmonary diffusing capacity to nitric oxide and carbon monoxide during exercise and in the supine position: a test-retest reliability study.

Alcoholic liver cirrhosis (ALC) is accompanied by sarcopenia. The aim of this study was to investigate the acute effects of balanced parenteral nutrition (PN) on skeletal muscle protein turnover in ALC. Eight male patients with ALC and seven age- and sex-matched healthy controls were studied for 3 h of fasting followed by 3 h of intravenous PN (SmofKabiven 1,206 mL: amino acid = 38 g, carbohydrates = 85 g, and fat = 34 g) 4 mL/kg/h. We measured leg blood flow and sampled paired femoral arteriovenous concentrations and quadriceps muscle biopsies while providing a primed continuous infusion of [ring-d]-phenylalanine to quantify muscle protein synthesis and breakdown. Patients with ALC exhibited shorter 6-min walking distance (ALC: 487 ± 38 vs. controls: 722 ± 14 m,  < 0.05), lower hand-grip strength (ALC: 34 ± 2 vs. controls: 52 ± 2 kg,  < 0.05), and computed tomography (CT)-verified leg muscle loss (ALC: 5,922 ± 246 vs. controls: 8,110 ± 345 mm,  < 0.05). Net leg muscle phenylalanine uptake changed from negative (muscle loss) during fasting to positive (muscle gain) in response to PN (ALC: -0.18 ± +0.01 vs. 0.24 ± 0.03 µmol/kg muscle·min;  < 0.001 and controls: -0.15 ± 0.01 vs. 0.09 ± 0.01 µmol/kg muscle·min;  < 0.001) but with higher net muscle phenylalanine uptake in ALC than controls ( < 0.001). Insulin concentrations were substantially higher in patients with ALC during PN. Our results suggest a higher net muscle phenylalanine uptake during a single infusion of PN in stable patients with ALC with sarcopenia compared with healthy controls. Muscle protein turnover responses to parenteral nutritional (PN) supplementation have not previously been studied in stable alcoholic liver cirrhosis (ALC). We applied stable isotope tracers of amino acids to directly quantify net muscle protein turnover responses to PN in sarcopenic males with ALC and healthy controls. We found a higher net muscle protein gain in ALC during PN, thereby providing the physiological rationale for future clinical trials of PN as a potential countermeasure to sarcopenia.

ArticleTotal : 2	Year
Publication title	2023
Publication title	2024

Article	Year
Danish evidence-based clinical guideline for use of nutritional support in pulmonary rehabilitation of undernourished patients with stable COPD. Clinical nutrition ESPEN\| PubMed ID: 28531445	2015
Comparative Effectiveness of Low-Volume Time-Efficient Resistance Training Versus Endurance Training in Patients With Heart Failure. Journal of cardiopulmonary rehabilitation and prevention\| PubMed ID: 29351130	2018
Lower mortality after early supervised pulmonary rehabilitation following COPD-exacerbations: a systematic review and meta-analysis. BMC pulmonary medicine\| PubMed ID: 30219047	2018
The role of lactate in sepsis and COVID-19: Perspective from contracting skeletal muscle metabolism. Experimental physiology\| PubMed ID: 34058787	2022
Therapeutic benefits of proning to improve pulmonary gas exchange in severe respiratory failure: focus on fundamentals of physiology. Experimental physiology\| PubMed ID: 34242438	2022
Regulation of the microvasculature during small muscle mass exercise in chronic obstructive pulmonary disease vs. chronic heart failure. Frontiers in physiology\| PubMed ID: 36134330	2022
Pulmonary diffusing capacity to nitric oxide and carbon monoxide during exercise and in the supine position: a test-retest reliability study. Experimental physiology\| PubMed ID: 36621806	2023
Skeletal muscle protein turnover responses to parenteral nutrition in patients with alcoholic liver cirrhosis and sarcopenia. American journal of physiology. Gastrointestinal and liver physiology\| PubMed ID: 37339940	2023

Ulrik Winning Iepsen

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