Pulmonary Testing Diagnostic Tests Fall 2023 PDF

Pulmonary Testing Diagnostic Tests Fall 2023 Common Obstructive Pulmonary Disorders Diffuse Airway Disease Upper-Airway Obstruction Asthma Foreign body COPD Neoplasm Bronchiectasis Tracheal stenosis Cystic fibrosis Tracheomalacia...

Pulmonary Testing Diagnostic Tests Fall 2023 Common Obstructive Pulmonary Disorders Diffuse Airway Disease Upper-Airway Obstruction Asthma Foreign body COPD Neoplasm Bronchiectasis Tracheal stenosis Cystic fibrosis Tracheomalacia Vocal cord paralysis Common Restrictive Pulmonary Disorders Parenchymal Pleural  Interstitial Lung  Effusion Diseases  Fibrosis - Fibrosis - Granulomatosis (TB) Chest Wall - Pneumoconiosis  Kyphoscoliosis - Pneumonitis (lupus)  Neuromuscular Disease  Loss of Functioning Tissue  Trauma - Atelectasis Extrathoracic - Large Neoplasm  Obesity - Resection  Abdominal Trauma  Tests of Pulmonary Function  Oximetry  Indirectly measures hemoglobin oxygen saturation and can suggest that the PaO2 is low.  It is prone to inaccurate measurements, particularly in individuals with poor peripheral circulation, and does not measure the PaCO2 or pH of the blood  Capnography  Measures the amount of CO2 in expired air and thus estimates PaCO2  Also prone to inaccuracy  6 minute-walks  COPD, pulmonary HTN, and fibrosis  Index of physical function and therapeutic response  Walk 400-700 meters  Used to qualify patients for home oxygen or oxygen with exertion 4 Bronchoscopy  Endoscopic visualization of the larynx, trachea, and bronchi  Either flexible fiberoptic bronchoscope or rigid bronchoscope Bronchoscopy  Diagnostic uses:  Direct visualization of tracheobronchial tree for abnormalities (tumors, strictures)  Biopsy of tissue  Aspiration of “deep” sputum for culture and sensitivity  Direct visualization of the larynx for identification of vocal cord paralysis  Therapeutic uses:  Aspiration of retained secretions in patients with airway obstruction or post-op atelectasis  Control of bleeding within the bronchus  Removal of foreign bodies that have been aspirated  Brachytherapy – endobronchial radiation therapy using an iridium wire placed by bronchoscope  Palliative laser obliteration of bronchial neoplastic obstruction  Bronchoscopy  Contraindications  Patients with hypercapnia and severe shortness of breath who can’t tolerate interruption of high-flow oxygen  Patients with severe tracheal stenosis  Potential Complications  Fever  Bronchospasm  Hemorrhage (after biopsy)  Hypoxemia  Pneumothorax  Infection  Laryngospasm  Aspiration  Cardiac arrest  Incentive Spirometry  A medical device used to help patients improve the functioning of their lungs  Provided to patients who have had any surgery that might jeopardize respiratory function  Particularly surgery to the lungs themselves  Also commonly to patients recovering from cardiac or other surgery involving extended time under anesthesia and prolonged in-bed recovery.  Also issued to patients recovering from pneumonia or rib fractures to help minimize the chance of fluid build-up in the lungs  The patient breathes in from the device as slowly and as deeply as possible, then holds his/her breath for 2–6 seconds.  This provides back pressure which pops open alveoli Incentive Spirometry Exhale first. Breathe in slowly and as deeply as possible. Notice the piston rising toward the top of the column. Hold your breath as long as possible. Then exhale slowly and allow the piston to fall to the bottom of the column. Rest for a few seconds and repeat steps one to 5 at least 10 times every hour. Position the yellow indicator on the left side of the spirometer to show your best effort. If you have an incision, support your incision when coughing by placing a pillow firmly against it.  Peak Flow Meter  Used to measure asthma control and estimate level of asthma exacerbations to base asthma action plan on  Find baseline for the patient – measure daily x 2-3 weeks while symptoms are controlled  Encourage patient to use Peak Flow Meter:  Every morning upon awakening before meds  During asthma symptoms/attack  After taking medicine for an attack (can use to see if medicine is working)  Treatment instructions based on what “zone” the reading is in  Green zone – 80-100% of usual or “normal” peak flow = All clear/Good control – continue meds as directed  Yellow zone – 50-80% of usual or “normal” peak flow = Caution – Follow directions for medications to use in the yellow zone of asthma action plan  Red zone - 10%  FEV1 increase of 200ml or 15% over baseline  FEF25-75% 20%-30% increase  Often given a trial even if no response is seen Bronchoprovocation  Pulmonary testing best utilized in diagnosis of allergy and exercise driven asthma  Reserved for patients who showed no change in full PFT or spirometry testing as well as bronchodilator post testing  Accurate diagnosis of asthma in selected patients, assessment of the response to asthma therapy, and, less commonly, identification of triggers for cases involving environmental or occupational exposures  Types:  **Pharmacological: Methacholine or Mannitol**  Exercise  Antigen Challenge  Food Challenge  Aspirin Challenge  Contraindications  Recent MI or CVA in the past 3 months  H/O unstable cardiac conditions  Signs of severe airway obstructive disease Bronchoprovocation  Pharmacological: Methacholine is most common due to its longer half life  Mechanism of Action: Bronchoconstriction via acetylcholine receptors  Increased increments of medication are administered  Pretesting spirometry is done followed by serial testing 30 and 90 seconds after increasing drug increments  Increments stopped once FEV1 has decreased > 20 % of baseline  Provocation dose is determined, < 200 micrograms: positive, > 400 micrograms: negative  Exercise: Exercise induced bronchospasms can be evaluated  Bronchodilators are withheld prior to testing  Baseline EKG, blood pressure, and pulse is also monitored  Treadmill or bike is used  Spirometry is performed prior to exercise, and at 5, 10, 15, 20, and 30 minutes thereafter  A test is considered positive if the forced expiratory volume in one second (FEV 1) decreases by 10 percent, although a fall of 15 percent is more diagnostic  Bronchodilators are on hand for any bronchospasm Stepwise Approach to Interpretation of PFTs  Step 1: Determine if the FEV1/FVC ratio is low  Step 2: Determine if the FVC is low  Step 3: Confirm the restrictive pattern (with DLCO)  Step 4: Grade the severity of the abnormality (use FEV1)  Step 5: Determine reversibility of obstructive defect  Step 6: Bronchoprovocation  Intentionally cause bronchoconstriction – used for asthma diagnosis  Methacholine challenge, mannitol inhalation challenge, exercise testing  Step 7: Establish the differential diagnosis  Step 8: Compare current and prior PFT results Copyrights apply Evaluation/Interpretation of PFT’s INTERPRETATION CRITERIA for us to use today: TEST NORMAL FVC >80% of predicted FEV1 >80% FEV1/FVC >70%  More specific criteria used:  American Thoracic Society  LLN (lower limit of normal) - measurement < 5th percentile from NHANES III data  GOLD – Global Initiative for Chronic Obstructive Lung Disease  FEV1/FVC < 70%  obstructive defect PFT Results Pre-Bronchodilator Post-Bronchodilator Predicted Measured % Measured % % change FVC 4.65 4.65 100 4.95 106 6 FEV1 3.75 3.13 83 3.34 89 6 FEV1/FVC 80 67 -13 67 -13 0 Predicted values are based on age, race, gender, BMI, height Is there obstruction? FEV1/FVC = 67% of predicted; therefore, obstruction present Is there restriction? FVC = 100% of predicted; therefore, no restriction present PFT Results Pre-Bronchodilator Post-Bronchodilator Predicted Measured % Measured % % change FVC 4.65 4.65 100 4.95 106 6 FEV1 3.75 3.13 83 3.34 89 6 FEV1/FVC 80 67 -13 67 -13 0 What is the severity of obstruction? FEV1 is 83% of predicted; therefore, the obstruction is mild Is the obstruction reversible (is reversibility present)? FEV1 increases from 83% to 89% (6% increase) and increases from 3,130 cc to 3,340 cc (increase of 210 cc) Interpretation: Mild Obstruction with minimal reversibility: Mild COPD  Case 1  A 65 year-old man undergoes pulmonary function testing as part of a routine health-screening test. He had no pulmonary complaints. He is a lifelong nonsmoker and had a prior history of asbestos exposure while serving in the Navy. Case 1 Questions  Do his results suggest obstructive pattern? How do you know?  Do his results suggest restrictive pattern? How do you know?  Case 1 Answer  This case demonstrates an example of normal pulmonary function tests.  The FVC and the FEV1 are 102% and 95% of predicted, respectively, values well above the lower limit of normal and the FEV1/FVC ratio is greater than the predicted value minus 8.  The flow-volume loop also corresponds quite nicely to the predicted values for this patient (darkened circles).  Based on this normal spirometry pattern, you would conclude that there is no evidence of air-flow obstruction.  The patient also has normal total lung capacity, indicating that there is no evidence of restriction, and a normal diffusing capacity for carbon monoxide, indicating that the alveolar-capillary surface area for gas exchange is normal.  There is no bronchodilator response. Case 2  A 54 year-old man presents to his primary care provider with dyspnea and a cough. He is a non- smoker with no relevant occupational exposures. Case 2 Questions  Does this show a restrictive or obstructive pattern?  What is the severity?  Is there significant bronchodilator response?  Case 2 Answer  The FVC and FEV1 are both below the lower limit of normal (defined as 80% of the predicted value for the patient). In addition, the FEV1/FVC ratio is only 0.68, less than the lower limit of normal of the predicted value minus 8 (80-8 = 72) for this male patient.  A low FEV1 and FVC with a decreased FEV1/FVC ratio is consistent with a diagnosis of air-flow obstruction.  With an FEV1 of 64% predicted this would be classified as “moderate” airflow obstruction.  In addition, the FVC improves by 0.81 L (25% increase) and the FEV1 improves by 0.65L (30% increase) following administration of a bronchodilator so this patient would qualify as having a bronchodilator response (defined as a 12% and 200 ml increase in either the FEV1 or FVC).  The flow volume loop also shows several abnormalities consistent with obstructive lung disease.  The peak expiratory flow rate is lower than the predicted peak expiratory flow and the curve has the characteristic scooped out appearance typically seen in airflow obstruction. Case 3  A 60 year-old man presents to his primary care provider with complaints of increasing dyspnea on exertion. He has a 40 pack- year history of smoking and is retired following a career as a building contractor. Case 3 Questions  Do the results represent obstructive or restrictive pattern?  What is the severity of disease?  According to GOLD classification, what treatment would be recommended for him?  Case 3 Answer  This patient has markedly abnormal spirometry. The FVC is only 41% predicted while the FEV1 is only 25% predicted, well below the lower limit of normal of 80% predicted.  In addition, the FEV1/FVC ratio is markedly reduced.  The combination of the low FEV1, FVC and reduced FEV1/FVC ratio is consistent with a diagnosis of airflow obstruction.  With an FEV1 of 25% predicted, this would be classified as “severe” airflow obstruction.  The patient also meets criteria for reversible airflow obstruction as both the FEV1 and FVC improve by over 200 ml and 12% following administration of a bronchodilator.  In addition to these abnormalities on spirometry, the patient has a markedly elevated residual volume (RV), a finding that is indicative of air-trapping.  The total lung capacity (TLC) is somewhat elevated at 117% predicted but it is still shy of the 120% predicted level used to define hyperinflation. Case 4  A 25 year old man presents to his physician with complaints of dyspnea and wheezing. He is a non-smoker. Two years ago, he was in a major vehicle accident and was hospitalized for 3 months. He had a tracheostomy placed because he remained on the ventilator for a Flattened total of 7 weeks. His tracheostomy was expiratory removed 2 months after his discharge. limb Flattened inspiratory lim Case 4 Questions  Is this consistent with obstructive or restrictive pattern?  What is the severity?  What does the Flow Volume Loop suggest about this patient? Case 4 Answer  This patient has evidence of airflow obstruction on spirometry as he has a low FEV1 and a reduced FEV1/FVC ratio of 0.54. Given that the FEV1 is 69% of predicted this patient would be labeled as having “mild airflow obstruction.  In order to make a correct diagnosis in this patient, however, you cannot look simply at the numbers from his spirometry testing but must also look at the flow volume loops.  A noteworthy feature of his flow volume loop is that there is flattening of both the inspiratory and expiratory limbs. This pattern is seen in patients who have a fixed upper airway obstruction.  In a patient with a prior history of tracheostomy, you would be very suspicious that this patient has developed tracheal stenosis, a known long-term complication of tracheostomy tubes  Other forms of airway obstruction will also demonstrate characteristic patterns on the flow-volume loops. Patients with a variable intrathoracic obstruction (eg. a carcinoid tumor in a mainstem bronchus) have flattening of the expiratory limb of the flow-volume loop while patients with variable extrathoracic obstruction (eg. a thyroid tumor) have flattening of the inspiratory limb of the flow-volume loop.  All three of these patterns are demonstrated in the figure below. QUESTIONS????