Objectives. Pulmonary Assessment 12/13/2017

Transcription

1 Pulmonary Assessment Reid Blackwelder, MD, FAAFP Professor and Chair, Family Medicine Quillen Colege of Medicine, ETSU Objectives Understand anatomy and physiology of pulmonary assessment techniques Remember approaches to CXR interpretation and ABG Recognize common spirometry patterns Know when to use provocative testing Control of Respiration Normal Oxygen Transport from Air to Tissues Normal Oxygen Transport from Air to Tissues Normal Respiratory Defense 1. Nose: Filters large particles (> 10um). 2. Vocal cords: Protects from aspiration. 3. Lower airway branching: Filters intermediate particles (2 10um). 4. Alveolar: A. Ciliary function. B. Macrophage. C. Secretory IgA. 5. Cough: Protective reflex mechanism that removes foreign particles and mucus from the airway. Effective cough requires: 1. Cough receptors 2. Afferent fibers 3. Cough center in the brain 4. Efferent fibers (phrenic & spinal motor nerves innervate diaphragm & intercostal muscles). 1

2 History Intial Assessment Physical exam Vitals Include pulse ox Watch (or instruct team) for changes with activity Subjective HPI Dyspnea Cough Wheeze Consider pulmonary and cardiac causes Past Medical History Lung problems Social Hx Smoking Environmental exposures Apnea Tachypnea Stridor Cough Wheezing Respiratory Signs and Symptoms Objective VS for tachypnea (>12-16) Description of habitus Tripod position Pectus Scoliosis Abnormal sounds (never listen through gown) Stridor Crackles/Rhonchi vs wheezes Results of maneuvers Pulmonary Findings on Exam Lung Sounds Effusion Consolidation COPD Pneumothorax Trachea Dev Contralateral None None Contralateral Fremitus Decreased Increased Decreased Decreased Nice link with basic review Percussion Dull Dull resonance resonance Pectoriloquy Decreased Increased Decreased Decreased Breath Sounds Decreased Decreased Crackles Decreased 2

3 Special Maneuvers Vocal fremitus Ulnar edge of hand on chest wall Patient says ninety-nine or one, two, three Increased vibrations from increased density Decreased from fatty tissue, COPD, effusion Percussion Most students and residents do not do this well! Dullness from consolidation, effusion Special Maneuvers Pectoriloquy/Egophony Spoken words are attenuated as they move through airspace If consolidation present, attenuation is reduced Increased transmission is pectoriloquy Ninety-nine again The change in pitch is called egophony Patient says eee heard as aay Remember pneumonia is a clinical not radiologic dx! CXR Method Cardiomegaly Airway Bones Cardiac Diaphragm Effusions Free Air Gadgets Hilum Interstitium Effusions Effusions 3

4 Infiltrate Where is the Infiltrate? Infiltrate Infiltrate Patterns and Pathogens CXR Pattern Possible Pathogens Lobar Patchy Interstitial Cavitary Large effusion S.Pneumo, Kleb, H flu, Gram Neg Atypicals, Viral, Legionella Viral, PCP, Legionella Anaerobes, Kleb, TB, S.Aureus,fungi Staph, Anaerobes, Kleb Brief Acid-Base Review ph 7.47 PCO2 20 HCO3 19 Dx? Respiratory alkalosis ph 7.25 PCO2 60 HCO3 27 Dx? Respiratory acidosis ph 7.10 PCO2 10 HCO3 6 Dx? Metabolic acidosis ph Determines Acidemia (< ) Alkalemia (>7.45) 4

5 Acidemia Alkalemia If the primary process is Metabolic The HCO3 must be < 24 Metabolic Acidosis If the primary process is Respiratory The pco2 must be > 45 Respiratory Acidosis If the primary process is Metabolic The HCO3 must be > 27 Metabolic Alkalosis If the primary process is Respiratory The pco2 must be << 40 Respiratory Alkalosis Evaluate Compensation! Metabolic Acidosis A Patient with DKA Decrease in pco2 = 1.3 (decrease in HCO3) pco2 will not go < 10 Max compensation takes hrs HCO3 8, and pco2 20 Decrease in pco2 = 1.3 (24 8) = 20.8 pco2 = = 19 Compensated Metabolic Acidosis A Patient with DKA HCO3 8, and pco2 28 Decrease in pco2 = 1.3 (24 8) = 20.8 pco2 = = 19 Inadequately compensated Metabolic Acidosis Possible etiology? Causes of Respiratory Acidosis CNS depression Sedative OD Acute airway obstruction COPD Pulmonary edema/infection Neuromuscular disorders Cardiopulmonary arrest 5

6 Causes of Respiratory Alkalosis Anxiety (hyperventilation) CNS tumor/infection/stroke Pulmonary emboli Pneumonia Drugs Salicylates, catecholamines, progesterone Hypoxia Fever Sepsis Lung Volumes IRV TV ERV RV IC FRC VC RV TLC 4 Volumes Inspiratory reserve Tidal Expiratory reserve Residual 4 Capacities Inspiratory Functional residual Vital Total Lung Residual volume (RV) Pulmonary Function Volume of air remaining in the lungs at the end of maximal expiration. Normally accounts for about 25% of TLC Increased in airway narrowing with Air trapping (Asthma) Loss of elastic recoil (emphysema). Decreased with Increased elastic recoil (pulmonary fibrosis) Office Spirometry Forced Expiratory Volume (FEV) Do it! Critical for diagnosis and management Convenient A procedure so you can charge for it 6

7 FEV1 Volume of air which can be forcibly exhaled from the lungs in the first second of a forced expiratory maneuver. Flow-Volume Loop: Air Flow vs. Volume Graphic representation of the inspiratory and expiratory maneuvers Effort Dependent flow-limiting segment at upper airways Peak Flow FEF 25% Effort Independent flow limiting segment at lower airways Flow-Volume Loop Obstruction Flow-Volume Loops Restriction Flow-Volume Loops FVC FEV1 Patterns of Impairment Obstructive Restrictive Normal/Big lungs Low Flow Nl or FEV1/FVC TLC Nl or RV Small lungs Normal Flow For low FVC, measure lung volumes 7

8 Spirometry Low FEV1/FVC Normal Low FVC Obstructive Suspect asthma Restrictive Methacholine Challenge Bronchodilator Trial FEV1 FEV1 Nl DLCO FEV1 No Change Asthma Normal Asthma COPD DLCO Nl: Bronchitis Emphysema Bronchoprovocation Testing PFTS are tools in the diagnosis of asthma Measurement of peak expiratory flow rate Spirometry May be normal between symptomatic episodes Asthma has characteristic variable airflow limitation Symptoms may only occur with certain exposures, activity Bronchoprovocation Testing Assesses Bronchial HyperResponsiveness to external triggers (BHR) Excessive response to an aerosolized provocation that triggers little or no response in a normal person Distinguishes most patients with asthma Useful if dx of asthma in question Establish dx of occupational asthma Methacholine challenge testing Cholinergic agonist, induces bronchoconstriction Patient inhales one or more increasing concentrations of Methacholine Spirometry before and after Test stopped if FEV1 decreases > 20% of baseline Negative if does not decrease by 20% with max dose: makes dx asthma very unlikely Exercise testing Inhale dry, cool air during exercise Ambient room temp F 50% relative humidity Treadmill or bicycle Exercise at target HR for at least 4 minutes Spirometry before and after over periods of time Abnormal is fall in FEV1 by 10% More than 15% suggests exercise induced bronchospasm 8

9 Take Home Points Good history and proper exam critical tools Fully evaluate CXR and ABG Office spirometry should be done! 9