A Systematic Evaluation of Endurance Impairments: Reversible & Irreversible Components

1. A Systematic Evaluation of Endurance Impairments:Reversible & Irreversible Components Konrad J Dias PT, DPT, CCS Maryville University St. Louis, MO Sean Collins PT, ScD, CCS University of Massachusetts Lowell, MA

2. Objectives • Identify relevant examination techniques (Information sources) to determine reduced endurance from cardiac, pulmonary and skeletal muscle dysfunction (Components of endurance). • Evaluate the results of an examination to assess reversible and irreversible mechanisms of reduced endurance. • Utilize the individual and integrated use of information collected from the examination process in creating appropriate treatment interventions and developing an appropriate prognosis for a variety of patient scenarios.

3. Brief outline • Definition of endurance impairments (Collins) • Criticality of causal discrimination in the evaluation of endurance impairments (Collins) • Components of endurance & Information sources (Dias) • Evaluation (Collins) • Intervention (Collins) • Discussion Questions (Dias & Collins) • Case Studies (Dias & Collins)

4. Definitions • Endurance – ability to sustain work for a requisite period of time to achieve necessary goals • Endurance impairment – inability to sustain work for a requisite period of time to achieve necessary goals • Endurance hierarchy – endurance emergence from complex multi system interaction for the sustained transfer of chemical to mechanical energy required for all work demands

5. Endurance Hierarchy Central Nervous System Muscular Activity Work Environment - Participation Environment Bioenergetics Work - Activities GI O2 H2O CHO Ventilation Body Structures & Functions Cardiovascular Respiration

6. Criticality of causal discrimination • Endurance hierarchy is true • Then, endurance emerges from complex multi system interaction • Then, many components of the system (or interactions of components) can lead to endurance impairment • Intervention is most effective when directed specifically at the cause of a problem • Therefore, it is critical to discriminate the cause of a problem to determine the most effective intervention (Tacit assumption for this talk is that this logic follows, and that it is possible to discriminate the probable cause (but not with certainty))

7. Components of Endurance & Information sources • Central • Ventilation • Minute Ventilation • Breathing pattern / Chest wall mechanics • Respiration • Gas exchange (SpO2, ABGs, observation) • Cardiac Pump (Hemodynamics) • Cardiac Output (HR, BP, PP) • Peripheral • Systemic Circulation • Blood flow to muscle • Arterial – venous oxygen difference • Muscle • Internal Respiration – Bioenergetics (Lactate, Symptoms) • Muscle activity – Force (Peak, duration)

8. Ventilation • Physiology of the Lung Pump • Pathologies affecting the lung • Assessing lung pump function

9. Pathologies affecting Lung Function • Obstructive lung disease • Restrictive lung disease • Neonatal Respiratory Distress Syndrome • Adult Respiratory Distress Syndrome • Neurological conditions

10. Information sources • Signs and symptoms • Breath sounds • Oxygen saturation • Pulmonary function tests • Chest X-ray • Dynamic hyperinflation

11. Respiration • External Respiration/ Gas Exchange • Conditions affecting gas exchange • Assessing Pulmonary Circulation • Diffusion of gases • Ventilation and perfusion matching

12. Conditions affecting Gas Exchange • Increase in ventilation at the interface • Decrease in ventilation at the interface • Increase in perfusion at the interface • Decrease in perfusion at the interface

13. Information sources • SOB • O2 saturation • Color • Lightheadedness • Swan-Ganz catheter • Breath sounds • RPE Scale

14. Cardiac Pump • Physiology of the Heart Pump • Pathologies affecting the heart • Assessing heart pump function

15. Physiology of the heart pump • Cardiac output • CO = HR *SV • Blood pressure • BP = CO * TPR • Rate pressure product • RPP = HR * SBP

16. Pathologies affecting the heart • Acute Coronary Syndrome • CHF • Dysrhythmias • Cardiomyopathy • Valvular insufficiency/stenosis

17. Information sources • Heart rate responses • Blood pressure responses • Ejection fraction • Angina and Rate pressure product • EKG changes • Heart sounds • Signs and symptoms of compromised cardiac output

18. Systemic Circulation • Systemic circulation physiology • Pathologies affecting systemic circulation • Assessing systemic circulation

19. Systemic Circulation • Blood flow to working muscles • Arterial venous oxygen difference

20. Pathologies affecting systemic circulation • Peripheral Vascular disease • Venous disorders • Anemia

21. Information sources • Ankle Brachial Index • Inspection for Skin color, nail and hair growth • Edema • Ulceration • Claudication

22. Muscle Activity • Muscle contraction • Pathologies affecting muscle activity • Assessing muscle function

23. Muscle Contraction • Muscle contractions during the gait cycle • Physiology: Blood flow to working muscles • Duty cycle of muscular activity • ON/ OFF • Gait efficiency • Slower gait less efficient.: When gait is slower, muscles are contracting isometric ally for a longer time and hence more ATP is required. • When gait is too fast, then efficiency reduced, as more ATP is required for accelerating the motion and facilitating a faster on/off cycle.

24. Pathologies affecting Muscle Activity • Deconditioning and Immobilization • Muscular dystrophy • Neuromuscular Diseases - Stroke • Nutritional disorders • Prolonged catabolic steroid use • Diabetes – BM • Chronic diseases

25. Information sources • Sit to stand • Gait cycle and relationship • Hand held dynamometer • Fatigue • RPE Scale

26. Evaluation • Against the backdrop of “typical” information (HPI, PMH, etc) • Keep in mind that presence of “cardiopulmonary” disease is not a perfect discriminator / determinant of central component cause of endurance impairment • Describe the endurance impairment • Activity • Intensity • Duration • Why is this an impairment? • What is the reason that the activity cannot be sustained? • Cannot do is different than cannot be sustained • Symptoms • Signs (measurable / observable indicators)

27. evaluation Activity (Mode, Intensity, Time*) cannot be Sustained Symptoms Signs Sustained Symptoms Signs Interpretation Interpretation: should be normal responses – could by “hypo” responses may include dyspnea Suspect / Abnormal – reversible vs. irreversible depends on cause – to what degree? Normal – assume reversible, but to what degree?

28. Time side bar…. Intensity – absolute and/or relative Time

29. evaluation Activity (Mode, Intensity, Time*) cannot be Sustained Symptoms Signs Sustained Symptoms Signs Interpretation Interpretation: should be normal responses – could by “hypo” responses may include dyspnea Suspect / Abnormal – reversible vs. irreversible depends on cause – to what degree? Normal – assume reversible, but to what degree?

30. Intervention Endurance Impairment Normal Central Response Abnormal Central Response Muscle Weakness No Muscle Weakness Irreversible Reversible Priority – treat the central response Priority – Strength training Priority – Aerobic conditioning Second – Aerobic conditioning Second – Strength training Muscle Weakness No Muscle Weakness *Critical Concept – Intensity is the determinant between “strength” and “aerobic” training; not mode, or whether it is a “functional” activity or not

31. discussion Questions • How do you currently discriminate between different etiologies of endurance impairment? • What purpose do baseline / resting measures have in your evaluation? • What discriminatory response (s) do you anticipate to workloads that are to high in an individual with: • Primary ventilation impairments? • Primary respiration impairments? • Ventilation induced respiration impairments? • Cardiac pump impairments? • Muscle weakness?

32. Discussion questions • What are some forms of reversible… • Ventilatory impairments • Respiratory impairments • Cardiac pump impairments • For those forms – what is the mechanism of reverse, what is the time course for the reversal, how do you determine the reversal is occurring?

33. Case Study 1 • A 65-year-old female has a 3-year history of diabetes and is currently referred for worsening dyspnea and cough. She has had chronic obstructive pulmonary disease (COPD) since age 55. She now has dyspnea with walking one-third of a block and a persistent cough. Her type 2 diabetes has been managed with diet and exercise. Chest X-ray: flattened diaphragm, hyperinflated, no infiltrates. Spirometry: forced vital capacity (FVC): 3.2; forced expiratory time in 1 second (FeV1): 1.4.

34. Case Study 2 • A 55-year-old obese male has a 3-year history of diabetes and is currently referred to you for weight loss and to help increase endurance. He has had chronic heart failure since age 50 following a heart attack affecting his left anterior descending artery. He now has dyspnea with walking one mile and a persistent cough. EF = 45%.

35. Thank you! Thank you your time and attention – we hope this has been of some benefit to you If you have questions / thoughts / comments and/or an interest in collaborating: KDias@maryville.edu Sean_Collins@uml.edu (PhD opportunities are available)