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1 Standard design cardiopulmonary system VO 2 max most important - PDF document

Dec 22, 2022 •474 likes •538 views

Disclosures NONE CPET in Children Dr Tim Takken Child Development & Exercise Center Wilhelmina Childrens Hospital UMC Utrecht Email: t.takken@umcutrecht.nl Twitter: @bikedocter Partner of Shared Utrecht Pediatric Exercise

  1. Disclosures NONE CPET in Children • Dr Tim Takken Child Development & Exercise Center Wilhelmina Children’s Hospital UMC Utrecht Email: t.takken@umcutrecht.nl Twitter: @bikedocter Partner of Shared Utrecht Pediatric Exercise Research Lab www.super ‐ lab.nl ; Twitter: @superlabutrecht Automobile Physiology…Performance related to Outline size • Equipment & protocols • Adult – child differences in CPET parameters • Example: CPET in CF Equipment for Pediatric CPET Protocols for pediatric CPET Aim: 6-10 min young children, 8-12 min adolescents Oxygen saturation Pediatric probe Lungfunction Small mask Gasanalyzers Sensitive flow meter Blood pressure Start Small cuff ECG Increment / min Small electrodes Warm-up: 3 min unloaded cycling Work load Small bike Increment in RAMP fashion Modified protocol Different norm values Godfrey S. Exercise testing in children. Philadelphia: WB Saunders, 1974 Dubowy KO, et al. Cardiol Young. 2008;18(6):615-23. Hebestreit H, et al Respiration. 2015 epub 1

  2. Standard design cardiopulmonary system VO 2 max most important design parameter All mammals have standard blue print: • Heart • Lungs • Vascular system • Muscles 10.000 x ISBN: 978-90-8891-998-5 Order via t.takken@umcutrecht.nl 5000 kg 500 gram Adult Child Differences in CPET parameters Peak Heart Rate Adults Children Cardiac Stroke Volume Cardiac Output Prado et al 2006 Prado et al 2006 2

  3. VO 2max (L/min) - Dutch Norms Arterio-venous Oxygen Difference Child Child ♂ ♀ Adult Adult +169% +136% Prado et al 2006 VO 2max/kg - Dutch Norms Blood Pressure Systolic Blood Pressure ♂ ♀ ~40-41 ~48-50 Work load Heck et al. Normwerte des Blutdrucks bei der Fahrradergometrie. Deutsche Zeitschrift fur Sportmedizin. 1984;(7):243-249 RER peak Breathing pattern at Peak Exercise Boys Girls • • 3

  4. Peak minute ventilation Oxygen Uptake Efficiency (Slope & Plateau Bongers BC, Hulzebos EH, Helbing WA, Ten Harkel AD, van Brussel M, Takken T. Response profiles of oxygen uptake efficiency during exercise in healthy children. Eur J Prev Cardiol. 2015 (epub). Ventilatory Drive (VE/VCO 2 slope) Criteria for maximal effort Subjective criteria: Objective criteria: Unsteady walking, RERpeak > 1.0 • • running or biking HRpeak> 180 beats/min • Sweating • VO 2 plateau in final minute • Facial flushing (infrequently observed) • Clear unwillingness to • continue CPET despite NB: never stop test if • encouragement criteria are met Important Adult-Child Differences Important Adult-Child Differences cont’ed Hemodynamic Difference with Adults Metabolic Difference with Adults – VO 2peak (L/min) Lower – Glycolytic activity Lower – Submaximal HR Higher – HRpeak Higher – Fat oxidation Higher – SV (sub)max Lower – CHO oxidation Lower – CO at %VO 2peak Lower – Peak blood lactate Lower – ∆ avO 2 at %VO 2peak Higher – Blood flow to muscle Higher – A-lactic capacity Lower – SBP , DBD Lower – Lactate clearance Same – Myocardial Ischemia Rare – Recovery after high Faster Ventilatory intensity exercise – Tidal Volume Lower – Respiratory Rate Higher – VE peak Lower – Ventilatory drive Higher – Ventilatory efficiency Lower 4

  5. Example: Exercise Testing in Patients with Cystic Fibrosis VO 2MAX & Survival WHY: CPET in CF - Applications (CF PATIENTS) • Routine monitoring and assessment of exercise- VO 2 max: related symptoms Low • Pretransplant assessment Medium High • Physical activity counselling/ recommendations/ exercise prescription • Interim functional assessment Nixon PA, Orenstein DM, Kelsey SF, Doershuk CF. The prognostic value of exercise testing in patients with cystic fibrosis. N Engl J Med. 1992;327(25):1785-8. Survival in contemporary 11-14 year old Exercise Limiting Factors in CF children with CF More than lung disease 127 cf patients • Mean age 12.7 years • FEV1: 77% • CPET (bike) • 7.5 years follow-up • Cardiac Output ‐ RV Stroke Volume Skeletal muscle dysfunction Ventilatory capacity ‐ LV Stroke Volume ‐ CFTR ‐ Airway obstruction ‐ Hypercapnia ‐ Work of breathing ‐ Hypoxemia ‐ Dynamic hyperinflation ‐ Systemic Inflammation ‐ CFRD ‐ Fat oxidation Hulzebos EH, Bomhof-Roordink H, van de Weert-van Leeuwen PB, Twisk JW, Arets HG, van der Ent CK, Takken T. Prediction of mortality in adolescents with cystic fibrosis. Med Sci Sports Exerc. 2014; 46(11):2047-52 5

  6. Poor relation between VO 2 peak and FEV 1 Relationship walk distance and FEV 1 (Children with CF) (Adult CF patients) Unpublished observation WKZ Doeleman, Takken, Bronsveld & Hulzebos, Physiotherapy, accepted Gender differences in CF Take-Home Messages • Also in children, never underestimate the power of CPET • When testing children, appropriate equipment and protocol should be used; • Because of the differences in physiology, pediatric reference values for CPET parameters should be used. Unpublished observation WKZ Thank You www.physiology-academy.nl 6

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