EHR519 Weeks 9 - 13

Revascularisation

• Restoration of perfusion to a body part or organ
• Myocardium = CABG (Coronary Artery Bypass Grafting) and PCI/PTCA (Percutaneous Coronary Intervention/Percutaneous Transluminal Coronary Angioplasty)

Exercise in Patients with CAD

• Common for clients with CAD and associated pathologies to experience angina
• Angina symptoms are a cascade of events referred to as the ischemic cascade:
  • Increased plaque, leading to an imbalance between O2 supply and demand in the myocardium
  • Abnormal diastolic function (ventricular compliance and impaired filling)
  • Systolic abnormalities (effecting preload, afterload, ejection fraction, cardiac output, etc.)
  • ECG changes – ST segment depression
  • Angina

Considerations - Medications

• Cardiac rehabilitation (CR) reduces the risk of future events
• International guidelines recommend patients have access to, and participate in, CR (for secondary prevention)
• Modern CR is multidisciplinary, including patient assessments, risk profiles, dietary advice, psychosocial support, individualised exercise prescription, and physical activity counselling

Contraindications to Exercise (Cardiac Rehab)

• Specific contraindications to exercise testing following revascularisation
• Stress testing following revascularisation:
  • Benefits and limitations of different test types (cardiorespiratory, strength, and ROM)
  • Special considerations for CABG and PTCA-stent

Exercise Prescription

• Inpatient (2-5 days for CABG, 1-2 days for PTCA-stent) and outpatient programs (supervised and unsupervised, at-home)
• Mode, frequency, intensity, and duration of exercise prescription
• Progression of exercise prescription from inpatient to outpatient

Chronic Heart Failure (CHF)

• Exercise testing is vital for CHF clients due to high mortality risk and response to medication and appropriate exercise prescription
• Testing protocols are similar to those with CAD
• Symptom-limited stress test with small workload increments
• Functional capacity, including work rates and HR responses, is crucial
• ECG monitoring and pulse oximetry during early exercise sessions

Accurate Assessment of Functional Capacity

• Recommended use of a metabolic cart
• Key measures: VE-VCO2, VO2peak, and % predicted
• VO2peak, ventilatory-derived lactate threshold (V-LT) using the V-slope method
• Functional tests for musculoskeletal strength and endurance are useful for planning and evaluating exercise programs

Contraindications

• Clients with stable HF routinely undergo symptom-limited maximum cardiopulmonary exercise testing to evaluate cardiorespiratory function
• Arrhythmias are common for clients with CHF
• If testing for ischemia, stress testing may be problematic due to ECG anomalies at rest
• Impaired thermoregulatory responses to heat exposure

Considerations - Medications

• Medications that tend to improve aerobic capacity: ACE inhibitors, ARBs, digoxin, diuretics, nitrates
• Medications that have little effect: calcium channel blockers, statins, anti-arrhythmics, and anti-thrombotics
• Chronic beta-adrenergic blockade has significant benefits on mortality and functional capacity
• Beta-blockers are mandatory in the treatment of CHF and blunt HR responses

Typical Chronotropic Responses

• Lower peak HR and failure to meet >85% maximum HR (20% decrease)
• HR responses: tachycardia at rest, absolute contraindication
• Body mass: increase of more than 1-2 kg compared to previous few days, likely due to fluid retention
• Questions relating to chest pain, worsening orthopnoea, exercise-induced dyspnoea, changes in physical and mental health and wellbeing

Exercise Prescription for CHF

• Clients with stable CHF, with medical clearance, are able to undertake an exercise program

Pacemaker Implantation

• 9782 pacemakers were inserted in Western Australia between 1995-2009, with a prevalence of 1 in 50 in people aged >75 years.
• Dual chamber and triple chamber pacing prevalence also increased during this period.

Pathophysiology

• Sick sinus syndrome refers to rhythm disorders involving the SA node, including the inability to generate a heartbeat or increase heart rate in response to changing circulatory demands.
• Symptoms of SA node dysfunction include fatigue, light-headedness, exercise intolerance, and syncope.
• AV conduction failure (AV block) occurs when impulses are blocked by the AV node, and ventricular activation is dependent on activation below the block.

Pacemaker Function

• A pacemaker may replace SA node signals that are slowed or blocked, or maintain normal timing between the upper and lower chambers.
• A pacemaker consists of separate but integrated components that stimulate the heart with precise timing.

Types of Pacemakers

• Pacemakers can be temporary or permanent, and may be single-chamber, dual-chamber, or triple-chamber.

Physiological Pacing

• Physiological pacing maintains the normal sequence and timing of contractions of both the atrium and ventricles.
• AV synchrony produces higher cardiac output without increasing myocardial O2 uptake.
• Dual-chamber pacemakers can improve efficiency, augment ventricular filling, and improve hemodynamic responses.

Rate-Responsive Pacing

• Rate-responsive pacing is used when the native SA node cannot increase heart rate to meet metabolic needs (e.g., during exercise).
• Sensors in the pacemaker sense exercise-induced changes and generate impulses to pace the heart.

Implantable Cardioverter Defibrillators (ICDs)

• ICDs are designed to detect and terminate lethal arrhythmias with an electrical shock.
• Combined pacemaker implementation and ICD therapy can reduce mortality by 40% compared to pacemaker alone.

Loop Recorders

• Loop recorders are implanted diagnostic tools used to monitor for cardiac arrhythmias, particularly in cases of unexplained syncope or palpitations.

Exercise Testing and Prescription

• Clients with pacemakers should undergo exercise testing to provide appropriate rate responses.
• Pacemaker settings can be adjusted to optimize responses during testing.
• Informal and formal exercise testing can be used to establish an upper rate limit, angina threshold, and ischemic threshold.

Exercise Prescription

• The sensor-driven heart rate increase rate follows pacemaker algorithms, with key parameters including the slope of the heart rate increase/decline and sensor sensitivity.
• Resistance training is safe, but clients should avoid activities that have direct contact with the pacemaker.
• Frequency, intensity, and duration of exercise will vary depending on the client's goals and co-morbidities.

Pulmonary System

• The pulmonary system has two main parts: pulmonary respiration (ventilation and gas exchange in the lungs) and cellular respiration (O2 utilization and CO2 production by the tissues)
• The respiratory system's purposes during exercise include gas exchange between the environment and the body, and regulation of acid-base balance

Conducting Zone

• Conducts air to the respiratory zone
• Humidifies, warms, and filters air
• Components: trachea, bronchial tree, bronchioles

Respiratory Zone

• Exchanges gases between air and blood
• Components: respiratory bronchioles, alveolar sacs
• Surfactant prevents alveolar collapse

Muscles Associated with Respiration

• (Not specified in the text)

Pulmonary Ventilation

• Respiratory airflow is governed by the same principles as blood flow: flow, pressure, and resistance
• Atmospheric pressure drives respiration: 760 mm Hg at sea level, lower at higher elevations
• Boyle's Law: at a given temperature, the pressure of a given quantity of gas is inversely proportional to its volume

Gas Exchange

• CO2 transport: 7% dissolved, 23% carbamino compounds, 70% bicarbonate
• O2 transport: 98.5% bound to Hb, 1.5% dissolved

Introduction to the Pulmonary System

• Overview of the pulmonary system, common diagnostic procedures, and nutritional considerations
• Learning outcomes: explain the pathophysiology of pulmonary conditions, outline risk factors and complications, explain diagnostic techniques and treatment procedures, demonstrate exercise/fitness/functional tests, and prescribe exercise as a therapeutic modality

Neural Control of Breathing

• Exact mechanism for setting the rhythm of respiration remains unknown
• Breathing depends on repetitive stimuli of skeletal muscles from the brain
• Controlled by 2 regions of the brain: cerebral and conscious, and automatic and unconscious (medulla oblongata and pons)
• Voluntary control over breathing originates in the motor cortex of the frontal lobe of the cerebrum
• Involuntary control involves respiratory nuclei in the medulla, dorsal respiratory group, and pons

Asthma in Australia

• 467 deaths in Australia related to asthma in 2022, with 299 female and 168 male deaths
• 2.8 million (11%) Australians had asthma in 2022, an increase from 10.2% in 2011-12
• Females had higher rates of asthma than males (12.2% compared to 9.4%), but boys aged 0-14 had higher rates than girls (10.1% compared to 6.2%)
• The prevalence of asthma was higher for people living in disadvantaged areas (13.2% compared to 10.2%) and those living with a disability (17.0% compared to 8.0%)
• 16% of First Nations people had asthma, a decrease from 18% in 2012-13

COPD in Australia

• 2.5% of Australians had COPD in 2022, a steady rate over the last decade
• The prevalence of COPD was similar between males and females (2.4% and 2.6%)
• 7.0% of people aged 65 years and over had COPD
• Current daily smokers were more likely to have COPD than ex-smokers or those who had never smoked
• 86.6% of people with COPD had two or more chronic conditions
• 1 in 10 adults who experienced severe or very severe bodily pain in the 4 weeks prior to the interview had COPD

Diagnostic Procedures

Spirometry

• Measures pulmonary volumes and rate of expired airflow
• Useful for diagnosing lung diseases and monitoring improvement or deterioration
• Spirometric tests include:
  • Vital capacity (VC)
  • Forced expiratory volume in 1 second (FEV1)
  • FEV1/FVC ratio
• Key differences between an obstructive and restrictive pattern:
  • Obstructive: both FEV1 and FEV1% are decreased
  • Restrictive: FEV1 is decreased, but FEV1% is normal or increased

Arterial Blood Gases

• Determine pH levels, bicarbonate (HCO3-), and partial pressures of O2 and CO2 in arterial blood
• Contribute to diagnosis and determine the need for oxygen therapy

Compensatory Processes

• Primary process is followed by a compensatory process
• Examples:
  • Primary respiratory acidosis (high PCO2) / acidemia: compensatory process = metabolic alkalosis (rise in serum bicarbonate)
  • Primary metabolic acidosis (low bicarbonate) / academia: compensatory process = respiratory alkalosis (low PCO2)

Imaging

• Chest roentgenogram (X-ray) is often used to differentiate between emphysema and chronic bronchitis
• Computed tomography (CT) scan has greater sensitivity
• Emphysema is characterized by large lung volumes, hyperinflation, flattened diaphragm, and vascular weakening

Bronchoscopy

• Involves insertion of a bronchoscope through the nose or mouth into the lungs to identify pathologies, remove foreign objects, or obtain a sample
• Typically performed after a CT or chest X-ray

Bronchial Provocation Test

• Assists in asthma diagnosis to assess sensitivity of the airways
• Involves inhalation of methacholine followed by spirometry assessments

Sweat Chloride

• Used for diagnosis of cystic fibrosis, considered the gold standard
• Higher chlorine concentrations in clients with CF
• Gene mutation testing determines if someone is a CF carrier or establishes diagnosis

Nutritional Considerations

COPD

• Malnutrition or nutritional depletion may be an issue for up to 25% of COPD clients
• Increased prevalence with severity of disease
• Malnutrition and associated weight loss have been identified as a predictor of mortality
• Causes of malnutrition are not well known, including reduced energy intake and increased caloric demand (higher BMR)
• Affects diaphragm contractile force

Pathophysiology of COPD

• Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous lung condition characterized by chronic respiratory symptoms, airflow obstruction, and abnormalities of the airways and/or alveoli.
• GOLD report 2023 outlines major risk factors: exposure to noxious particles, genetic syndromes, abnormal lung development, and oxidative stress-induced accelerated aging.

Clinical Presentation and Diagnostic Criteria

• Typical COPD symptoms include dyspnea, wheezing, chest tightness, fatigue, activity limitation, and/or cough with or without sputum production.
• Diagnosis is based on the presence of non-fully reversible airflow limitation (FEV1/FVC < 0.7 post-bronchodilation) measured by spirometry.
• Some individuals may have structural lung lesions (e.g., emphysema) and/or physiological abnormalities (low-normal FEV1, gas trapping, hyperinflation) with an FEV1/FVC ratio ≥ 0.7 post-bronchodilation, classified as 'Pre-COPD' or 'PRISm'.

COPD vs Asthma

• COPD is characterized by chronic airway inflammation and hyper-responsiveness of the tracheobronchial tree, whereas asthma is characterized by recurrent airflow obstruction with symptom-free periods.
• Patients experiencing a combination of asthma and COPD features are diagnosed with asthma and COPD overlap syndrome.

Factors that Influence COPD Progression

• Genetic factors, age >45 years, gender, race, lung growth and development, exposure to particles, socioeconomic status, asthma, airway hyper-reactivity, chronic bronchitis, and infections can influence COPD progression.

Pathology, Pathogenesis, and Pathophysiology

• Pathology: chronic inflammation, structural changes
• Pathogenesis: oxidative stress, protease-antiprotease imbalance, inflammatory cells, inflammatory mediators, peribronchiolar and interstitial fibrosis
• Pathophysiology: airflow limitation and gas trapping, gas exchange abnormalities, mucus hypersecretion, pulmonary hypertension

Pathogenesis of COPD - Inflammation

• Inflammation is present in all areas of the lungs as a protective response to inhaled toxins, leading to tissue destruction, impairment of defense mechanisms, and disruption to repair mechanisms.
• Smoking and associated inflammation contribute to an imbalance between oxidants and antioxidants, creating an environment of oxidative stress in the lung.

Inflammatory Markers and COPD

• Increased numbers of neutrophils, macrophages, T lymphocytes, and release of cytokines and mediators, such as leukotriene B4, chemotactic factors, pro-inflammatory cytokines, and growth factors, reflect the degree of airflow obstruction.

Protease and Anti-Protease Imbalance

• Protease: enzymes that break down proteins and peptides
• Up-regulation of proteases and inactivation of anti-proteases lead to an imbalance, which is exacerbated by cigarette smoke and inflammation.

Oxidative Stress

• Sources of oxidants include cigarette smoke and reactive oxygen and nitrogen species released from inflammatory cells, leading to an imbalance in oxidants and antioxidants.
• Markers of oxidative stress are increased in stable COPD and are further increased in exacerbations.

Pathophysiology of COPD

• Primary risk factor for developing COPD: tobacco smoke
• Secondary effects on skeletal muscle
• Specifically, sites affected by COPD include:
  • Bronchi: enlarged mucus glands and dilated gland ducts
  • Bronchioles: mucus plugging, inflammation, increased airway smooth muscle tone
  • Pulmonary parenchyma and vasculature: loss of alveoli wall support, diminished elastic recoil, and increased work by respiratory muscles to meet ventilatory demands.

COPD and Exercise

• COPD patients who demonstrate less dynamic hyperinflation, desaturate less, and are less breathless tend to perform greater amounts of work.
• One-leg cycling can have benefits similar to conventional cycling.

Resistance Training for COPD Clients

• Use free weights or machines, with an emphasis on functional activities.
• Frequency: 2-3 times a week, with 1-4 sets per exercise.
• Progression: Gradually increase resistance and reps as strength increases.
• Goals: Improve respiratory muscle strength and endurance, and reduce dyspnea.

Considerations for Clients with COPD

• Signs and symptoms: dyspnea, cough, sputum production, wheezing, chest tightness, and occasional fever.
• Diagnosis is based on medical history, physical examination, and laboratory results (spirometry, CT scan, and x-ray).
• GOLD recommendations include comprehensive medical history, physical examination, and laboratory results.

Exercise Testing for COPD

• Important for clients with COPD, even mild-to-moderate, as symptoms often do not present until increased demand is placed on the respiratory system.
• Exercise testing is used to track the progression of disease, detect exercise hypoxemia, and determine the need for supplemental oxygen during exercise training.

Modes of Exercise Testing

• Treadmill testing: constant work rate protocols, with incremental increases in workload and slow progression.
• Cycle ergometer testing: unloaded cycling for 3 minutes, followed by ramped protocol.
• 6-minute walk test: field walking test, either self-paced or externally paced, over a predetermined time or distance.

Special Considerations

• Arm ergometer testing may limit the intensity and duration of exercise due to increased dyspnea.

Flexibility and Stretching for COPD

• Mode: balance, stretching, Tai Chi, and modified yoga.
• Intensity: stretch to the point of tightness, not pain.
• Frequency: >2 times a week, with 10-60 seconds of stretching.
• Goals: increase range of motion, improve gait and balance, and improve breathing efficiency.

Ventilatory Muscle Training

• Recommended for COPD patients to increase ventilatory muscle strength and endurance, alleviate dyspnea, and improve health-related quality of life.
• Techniques:
  • Voluntary isocapnic hyperpnea
  • Inspiratory resistive loading
  • Inspiratory threshold loading
• Guidelines: 4-5 times a week, 2-4 sets per exercise, with an intensity of ≥30% maximal inspiratory pressure.

Benefits of Training for COPD Clients

• Improved exercise capacity
• Reduced dyspnea
• Improved health-related quality of life

Pathophysiology of Asthma

• Asthma is a heterogeneous disease characterized by chronic airway inflammation, defined by the history of respiratory symptoms, such as wheeze, shortness of breath, chest tightness, and cough, that vary over time and in intensity, together with variable expiratory airflow limitation.
• Hyperresponsiveness of the airway to direct and indirect stimuli and can involve chronic inflammation.
• Symptoms typically resolve (transient) with experiences of flare-ups, but pathology may be present even when symptoms are not present.
• Around 2.7 million Australians had asthma in 2017-18, with a prevalence of 11% in 2020-21, which is higher for females over the age of 15.

Asthma Phenotypes

• Allergic asthma: easily recognized, often commences in childhood, associated with a past and/or family history of allergic disease, and sputum examination shows airway inflammation.
• Non-allergic asthma: the cellular profile of the sputum may be neutrophilic, eosinophilic, or contain only a few inflammatory cells, and demonstrate a lesser short-term response to ICS.
• Adult-onset (late-onset) asthma: particularly women, present for the first time in adulthood, mostly non-allergic, and often require higher doses of ICS or relatively refractory to corticosteroid treatment.
• Asthma with persistent airflow limitation: some with long-standing asthma develop airflow limitation that is persistent or incompletely reversible (from airway wall remodeling).
• Asthma with obesity: some obese patients with asthma have prominent respiratory symptoms and little eosinophilic airway inflammation.

Environmental Factors

• Pathophysiology: 3 components to asthma, including airway inflammation, intermittent airflow obstruction, and bronchial hyperresponsiveness.
• Environmental factors: allergens (indoor and outdoor), infections, smoking, diet, and medications.
• Host factors: genetics, obesity, and gender.

Airway Inflammation

• Can be episodic and variable, but airway inflammation is persistent.
• Inflammation, and thus obstruction, is primarily in the medium-sized bronchi.
• CD4 lymphocyte promotes inflammation through immunoglobulin E, eosinophils, basophils, and mast cells.
• Inflammation promotes oedema, structural changes (remodeling of airways), hypertrophy, and hyperplasia of airway wall, and angiogenesis and increased submucosal gland size.

Diagnosis

• Lung function testing to document variable expiratory airflow limitation.
• Bronchial provocation tests: inhaled methacholine, histamine, and moderately sensitive for a diagnosis of asthma but have limited specificity.
• Allergy tests: atopy increases the probability of allergic asthma, but is not specific for asthma or present in all phenotypes.

Diagnostic Criteria for Asthma

• Chest radiographs: identify changes such as bronchiectasis (irregular and dilated airways).
• Spirometry assessments: reduced FEV1 and forced expiratory flow, and hyperinflation.
• Lower the FEV1, the more severe the disease.

Cystic Fibrosis

• Effects on the gastrointestinal system: exocrine pancreatic insufficiency, malabsorption of nutrients, and increased need for higher caloric intake and poor utilization.
• Effects on the metabolic system: cystic-fibrosis-related diabetes, pancreatic scarring, and insulin secretion.

Effects of Cystic Fibrosis

• Correlation between ideal body mass and effects on respiratory system.
• Gastrointestinal tube may be required for advanced nutritional issues.
• Other common conditions included liver disease, endocrine pancreatic insufficiency, and gallbladder disease.

Exercise Testing and Prescription for Asthma and Cystic Fibrosis

Asthma

• Exercise testing is not generally required for individuals with asthma, unless exercise tolerance is reduced disproportionately to symptoms or air-flow limitations.
• A symptom-limited incremental test is completed, including assessments of oxyhemoglobin saturation and ECG, with optional respiratory gas analysis and anaerobic threshold.
• Contraindications to consider include acute bronchospasm, chest discomfort, increased shortness of breath, and severe deconditioning or co-morbidities.

Exercise-Induced Bronchospasm (EIB or EIA)

• Pathophysiology: related to the consequences of heating and humidifying large volumes of air during exercise, leading to mast cell degranulation, eosinophil activation, and bronchoconstriction.
• Symptoms: dyspnea, cough, tightness in the chest, wheezing, and sputum production.
• Development of EIB is related more to water content than temperature.
• Diagnosis requires bronchoprovocation challenge with pre- and post-spirometry testing, with a protocol involving rapid increase in intensity of 2-4 minutes, breathing dry air.
• Two most important determinants of EIB are sustained high-level ventilation during exercise and water content.
• Pre-exercise warm-up is important to reduce the risk of EIB.
• Bronchodilator, anti-inflammatory, or leukotriene modifier therapy should be delivered 15 minutes prior to exercise.

Exercise Prescription for Asthma

• Variety of exercise prescription reflects the vast range of symptoms, severity, and limitations to airflow.
• Mode and intensity should reflect training status, interests, and goals.
• Exposure to cold air, low humidity, and air pollutants should be minimized.
• GXT is performed, starting below VT, with an intensity of 50-85% HHR.
• If maximal test was completed, initial exercise intensity should be just below AT.
• ACSM recommendations include avoiding triggers resulting in bronchoconstriction, adequate warm-up, and use of bronchodilators prior to exercise.

Cystic Fibrosis

• Exercise testing is important for monitoring and managing clinical status, pre-transplant assessment, counseling, and education.
• Testing should include a standardized GXT to maximum using a treadmill or cycle ergometer, with monitoring of data pre-, during, and post-GXT, utilizing ECG and pulse oximetry.

Exercise Prescription for Cystic Fibrosis

• Aerobic exercise: daily, moderate to vigorous intensity, 30-60 minutes, with progression of 10% every 2 weeks.
• Resistance training: 2-3 times a week, 1-3 sets, 8-12 reps, with mild progression.
• Flexibility: daily, 10-30 seconds per stretch, pain-free, with natural progression.
• Daily physical activity: 60 minutes a day for young children and children, with an emphasis on airway clearance, coughing, and huffing.

Benefits of Aerobic Exercise Training

• Improvements in FEV1 when aerobic and resistance training are utilized.
• Improvements in dynamic lung function, including lower RHR, increased Hrmax, improved VO2max, and increased work capacity.
• Greater training effects with higher intensity programs.
• Exercise training during hospitalizations is also useful with chest physiotherapy and bronchial drainage.

Benefits of Muscular Strength and Endurance

• Benefits of anaerobic function have mixed results.
• Resistance training + home cycling has been shown to increase muscular strength, vertical jump, flexibility, and balance.
• Muscle limitations include decreased muscle size and metabolic abnormalities leading to reduced strength.
• Longer rest periods may be required, and muscle wastage may occur due to medications for CF clients post-lung transplant.

Benefits for Body Composition, Nutrition, and Mental Health

• Exercise limitations occur independent of nutritional concerns.
• Exercise can increase body mass independent of caloric needs.
• Nutritional supplementation can support improved aerobic capacity and tolerance, and respiratory muscle strength.
• Exercise can improve wellbeing, reduce rates of depression and anxiety.