Pulmonary Function Tests & Interventions PDF

Pulmonary Function Tests & Interventions Rachel Elbing PA-C, MPH Augsburg PA Program Fall 2024  Objectives 1. Summarize the parameters of pulmonary function testing including: Tidal volume (TV) Inspiratory Reserve Volume (IRV) Inspiratory...

Pulmonary Function Tests & Interventions Rachel Elbing PA-C, MPH Augsburg PA Program Fall 2024  Objectives 1. Summarize the parameters of pulmonary function testing including: Tidal volume (TV) Inspiratory Reserve Volume (IRV) Inspiratory Capacity (IC) Expiratory Reserve Volume (ERV) Vital Capacity (VC) Residual Volume (RV) Functional Residual Capacity (FRC) Total Lung Capacity (TLC) Peak Flow Forced Expiratory Volume in 1 Second (FEV1) Forced Expiratory Flow (FEF) 2. Recognize the indications for pulmonary function testing and interpret the findings. 3. Summarize the management of pulmonary conditions utilizing oxygen, nebulizers, various inhalers, and chest physiotherapy. 4. Establish a framework for the components of pulmonary rehabilitation following acute lung illness, injury, or exacerbations of chronic disease PFT (Pulmonary Function Test) Indications Evaluation of signs/symptoms ○ Cough ○ SOB ○ Wheezing ○ Hypoxemia ○ Hypercapnia ○ Crackles Abnormal chest XR or CT Assessment & monitoring of disease severity & progression ○ Pulmonary Rehab ○ Occupational Exposures Monitoring drug efficacy Pre-operative assessment Screening at risk patients PFTs Spirometry ○ Measurement of volume vs time ○ Volume based on how much one can inhale/exhale Flow-Volume loops Lung volume determination (body plethysmography) ○ Gold standard for lung volume ○ Total lung volume determination Diffusion capacity ○ Diffusion liters carbon monoxide (DLCO) ○ Used to assess gas exchange ability of the lungs ○ >75% of predicted is normal Bronchodilator response testing  PFT Contraindications Recent MI or chest pain Recent or untreated pneumothorax Pulmonary embolism w/i past 3 months Recent surgery (eye, chest, abdomen)  Variability of PFTs “Normal PFTs” vary with age, sex, height Health Equity Concern: Spirometers previously used correction factors based on race Previous studies found lower lung function in Black patients so this was used as different baseline Inaccurate estimates of lung function result in misclassification of disease severity and affect ATS (American Thoracic Society) 2023 recommendation to “ replace race and ethnicity- specific equations with race-neutral average reference equations, which must be accompanied with a broader re-evaluation of how PFTs are used to make clinical, employment, and insurance decisions” https://www.thoracic.org/about/newsroom/press-releases/journal/2023/pft-and-race-offic ial-statement.php Examples of PFT  Definitions Tidal volume (TV): volume of air moved during normal breath on quiet respiration Inspiratory Reserve Volume (IRV): Maximum volume of air inhaled AFTER normal inhalation Inspiratory Capacity (IC): Maximum volume of air that can be inhaled (TV + IRV) Expiratory Reserve Volume (ERV): Maximum volume of air exhaled AFTER normal exhalation (Forced) Vital Capacity (FVC/VC): Maximum amount of air that can be exhaled after maximal inspiration Residual Volume (RV): volume of air left in lungs after maximal expiration (calculated) Functional Residual Capacity (FRC): Volume of air in lung at end of normal expiration (RV + ERV) Total Lung Capacity (TLC): Volume of air in lungs after maximal inspiration (VC + RV) Peak Flow: Maximal flow rate that can achieved during forceful expiration (L/min) Forced Expiratory Volume in 1 Second (FEV1): Amount of air forcefully exhaled in 1 second Forced Expiratory Flow (FEF): Measurement of flow/speed of air being exhaled during portions of expirations - often given at discrete times (i.e. what fracture of the FVC has been exhaled) Whiteboard time Flow-volume loops  Interpretation of PFTs Forced vital capacity (FVC): Maximum air inhaled & exhaled ○ Decreased in restrictive lung disease ○ Often decreased with obstructive disease Forced expiratory volume in 1 sec (FEV1): Max volume of air exhaled in 1 sec ○ Decreased in restrictive lung disease ○ Significantly decreased with obstructive disease In normal lungs, > 70% of FVC is exhaled in first second FEV1/FVC ratio: decreased in obstructive disease, normal in restrictive Lung Disease: Restrictive vs Obstructive RESTRICTIVE OBSTRUCTIVE Hard time fully expanding Narrowing of pulmonary their lungs when inhaling airways hinder person’s ability to completely Reduced compliance and expel air from the lung volume lungs Can be intrinsic (diseases of Decreased elasticity of parenchyma) or extrinsic lung (extrapulmonary - neuromuscular disorders) “Air trapping”  Interpretation of PFTs Abnormal if… FEV1 < 80% of predicted FVC < 80% of predicted FEV1/FVC ratio 0.7 (70%) COPD, asthma, bronchiectasis Interstitial lung disease, scoliosis, neuromuscular disease Obstructive Vs Restrictive Obstructive Restrictive Vital Capacity N or Total Lung Capacity N or Residual Volume FEV1/FVC N or Additional testing with PFTs Pre- and post- bronchodilator spirometry done to evaluate for reversibility (i.e. ASTHMA) ○ Reversible if FEV1 or FVC increased by at least 12% and 200mL Bronchoprovocation testing for reactive airway disease - Methacholine challenge ○ Methacholine is a non-specific cholinergic agonist (parasympathomimetic) that acts through muscarinic receptors in the lungs to induce bronchoconstriction DLCO - Diffusion Capacity Measures ability of lungs to transport inhaled gas from alveoli to pulmonary capillaries Depends on… ○ Alveolar-capillary membrane ○ Hgb concentration ○ Cardiac Output Decreased DLCO ○ COPD (emphysema), parenchymal disease, pulmonary vascular disease, anemia Normal DLCO ○ COPD (chronic bronchitis), asthma, extrinsic lung disease (chest wall) Increased DLCO ○ Increased perfusion - exercise, polycythemia Interpreting PFTs - DLCO Management of Pulmonary Conditions Oxygen Nebulizers Inhalers Peak Flow Meters Chest Physiotherapy Oxygen “Supplemental Oxygen (O2)” ○ Used for hypoxemia ○ Carbon Monoxide Poisoning ○ Cluster headaches We breathe 21% O2 (“room air”) Delivered in multiple ways ○ Supplemental: nasal cannula, face mask ○ Supplemental + respiratory assistance/support: CPAP & BiPAP ○ Full ventilatory and oxygenation support: Intubation and ventilator Supplemental O2 Devices  Inhalers Medication in pressurized canister, delivered w/ propellant Asthma, COPD, pneumonia, acute bronchitis Convenient, portable Need to use correctly - spacer Similar formations as nebulizers Nebulizers Medical device to deliver mist for inhaling a medicinal drug Asthma, COPD, pneumonia, bronchiectasis, croup Less dependent on user (unlike inhaler) Types: ○ Short-acting beta 2 agonist - albuterol ○ Short-acting anticholinergic - ipratropium (Atrovent) ○ Long-acting beta 2 agonist - formoterol/salmeterol ○ Inhaled corticosteroids - budesonide (Pulmicort) ○ Alpha/Beta Agonist - Racemic Epinephrine Peak-Flow Meters  Chest Physiotherapy Used in patients with cystic fibrosis, pneumonia, bronchiectasis, neuromuscular disorders Bronchial hygiene to mobilize bronchial secretions to large airways → cough ○ Postural Drainage ○ Chest percussion/vibration ○ High frequency chest wall oscillation Chest Physiotherapy  Pulmonary Rehabilitation Multidisciplinary intervention for patient with chronic respiratory disease who are symptomatic and quality of life is affected Goal: reduce symptoms, optimize function status, increase participation and reduce health-care costs Common conditions COPD and asthma Pulmonary HTN Cystic Fibrosis Transplant (before and after) Usually 2-3 weekly sessions for several weeks or months Common testing Exercise stress test to measure O2 level, BP and HR Pulmonary function testing Six-minute walk test - measure distance in six minutes Common components of Pulmonary Rehab Breathing techniques Education on disease process Social activity Psychological Counseling Nutritional Counseling Smoking cessation Advanced Care Planning Recheck lung function at end of program Big sigh…Thank you!