Vermont Genetics Network Annual Retreat August 7 2013 Hans Christian Haverkamp PhD Johnson State College Search Google for Biomedical Research Research in the Exercise Physiology Lab ID: 1038229
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1. Lung Mechanical Control of Airway Function During Exercise in the Asthmatic AdultVermont Genetics NetworkAnnual RetreatAugust 7, 2013Hans Christian Haverkamp, Ph.D.Johnson State College
2. Search Google for “Biomedical Research”
3. Research in the Exercise Physiology Lab
4. Research in the Exercise Physiology LabAtmosphericPressureIntrapulmonaryPressure(Ppul ,Palv)IntrapleuralPressure(Pip , PPL, PL)TranspulmonaryPressure=Ppul - PipChest wallPleuraePressure = R(V) x E(V’)
5. Lung function is variable in the asthmaticAirway functionNormalImpairedJANJUNDECMARSEPSeasonal VariationDaily Variation12:00am12:00pm11:00pm6:00am6:00pmAirway functionNormalImpairedCircumstantial VariationVisit friend w/catBronchodilatorAirway functionNormalImpaired
6. Study 1: Question & PurposeWhat is the effect of variable pre-exercise airway function on the responses to whole-body exercise in asthmatic humans?Pulmonary systemVentilationAirway mechanicsDetermine effects of improved and worsened pre-exercise airway function on the pulmonary system responses to whole-body exercise in asthmatic humans
7. Experimental designFourExperimental StudiesAlbuterol (BD)Hyperpnea (BC)SHAM (hyperpnea)ControlExercise
8. Outcome dataExercise ventilationTidal volumeLiters/breathBreathing frequencyBreaths/minuteMinute ventilationLiters/minFlow-volume loopsAirflow(L/sec)Volume (L)10854
9. Altered pre-exercise lung functionΔ = 1.4 L*Relativeairway diameter
10. No effect of variable pre-exercise airway function on exercise ventilationVE/VCO2Minute ventilationL/minL/breathBPMTidal volumeBreathing frequency
11. Exercise-induced bronchodilationPre-exercisePost-exercise
12. Exercise-induced bronchodilation allows for adequate ventilation during exercisePre-exercisePost-exercise
13. Study 1: Summary & ConclusionsDespite highly variable pre-exercise airway function:Exercise ventilation similarSignificant exercise-induced bronchodilationAllows for adequate exercise ventilatory responseIn mild-to-moderate asthma, the pulmonary system is robustly responsive to increased demand for airflow during whole-body exerciseMechanisms for exercise bronchodilation???Lung mechanical mechanismsCurrent studies
14. The airways are embedded within the lung parenchymaWeibel, Am J Respir Crit Care Med, vol 187, 2013Airways tethered open by lung parenchyma
15. Study 2: Purpose & HypothesisPurpose: Determine effects of lung inflation on airway diameter during whole-body exercise in asthmatic adultsHypothesis: Increased ventilation and tidal volume – and thus lung inflation – provides the principle physiological stimulus for changes in airway diameter during exercise in asthmatic adults
16. 4 minute exercise stagesWorkload(% max)4070Tidal volumeBreathingfrequencyMinuteventilationRestSpontaneous VESpontaneous fbSpontaneous VTIso VEIso fbIso VTExperimental Design Forced exhalations Pulmonary resistance
17. Airway diameter fluctuates during variable intensity exercise in asthmaWorkload(% max)4070BLExercise
18. Airway diameter fluctuates despite maintained tidal volume and minute ventilationVE Δ, 23 L/minVT Δ, 0.25 LWorkload(% max)4070vv
19. Stationary isocapnic replication of exercise ventilation
20. Stationary isocapnic hyperpnea causes bronchodilation but not fluctuating airway diameterWorkload(% max)4070RestRest
21. SummaryBronchodilation occurs during whole-body exercise in the asthmatic adultAllows for adequate exercise ventilation despite variable baseline lung functionAirway function is dynamic during variable workrate exercise in the asthmatic↑ exercise intensity = bronchodilation↓ exercise intensity = bronchoconstrictionChanging lung volume during exercise does not account for the variable airway functionNeural mechanismsChemical mediator mechanismsLung and airway mechanical mechanisms
22. Undergraduate Research AssistantsUndergraduate studentsAdriane Morrison-Taylor*Jeni Demar*Andrew Klansky*Adam Lacayo*Matthew RossmanSusan NaderFrancesca OrsiniDustin BerryINBRE, NIGMS, NCRR