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Pulmonary Function Test interpetation ppt
- 1. Chairperson: Asst. Prof. Dr.Snehangshu Shekhar Samanta Presenter : Dr. Arijit Biswas
- 2. Its ageneric term used to indicate a battery of test or manouvers performed using standardised equipment to evaluate function of lung.
- 3. 1. Tests forventilatory functions: Evaluate lung volumes and capacities: - Spirometry - Body Plethysmography - Gas dilution method ( FRC & RV detection) Evaluate hypersensitivity of airway - Bronco provocation test
- 4. 2.Tests for gasexchange: DLCO , ABG, Oxymetry and Capnography. 3. Other Tests: Tests for lung compliance. Test for resistance and impedence: Impulse oscillometry. Assessment of regional lung functions. Assessment of respiratory muscle strength. Breath condensate.
- 5. Gives theevidence of deranged lung function Helps to rule out/ identify resp cause of SOB Quantifying lung function in pt undergoing lung resection Type of resp failure Detects airway hyper responsiveness Evaluation of disability Course of disease over time
- 7. VOLUME DISPLACEMENT SPIROMETER: FLOWSENSING SPIROMETER:
- 8. 500ml 4.5l 1.2+1 L 1.2L 1L 4.5+1.2L 3L TV= AMOUNT OF GAS GOING IN AND OUT WITH EACH RESPIRATION
- 9. 500ml 4.5l 1.2+1 L 1.2L 1L 4.5+1.2L 3L IRV= EXCESS AIR THAT CAN BE BREATHED IN WITH EXTRA EFFORT AFTER TIDAL INSPIRATION
- 10. 500ml 4.5l 1.2+1 L 1.2L 1L 4.5+1.2L 3L ERV= EXTRA AMOUNT OF GAS THAT CAN BE BREATHED OUT WITH EXTRA EFFORT AFTER TIDAL EXPIRATION
- 11. 500ml 4.5l 1.2+1 L 1.2L 1L 4.5+1.2L 3L RV= AIR LEFT BEHIND AFTER MAX EXPIRATION
- 12. 500ml 4.5l 1.2+1 L 1.2L 1L 4.5+1.2L 3L FVC= AMOUNT OF AIR THAT CAN BE BREATHED OUT WITH MAX EFFORT AFTER FORCEFUL INSPIRATION
- 13. 500ml 4.5l 1.2+1 L 1.2L 1L 4.5+1.2L 3L FRC= AMOUNT OF AIR LEFT IN LUNG AFTER NORMAL TIDAL EXPIRATION
- 14. It canmeasure: 1. Tidal vol (500ML) 2. IRV (3L) 3. ERV (1L) 4. VC (4.5L) What it can not measure: 1. RV 2. FRC = ERV+ RV 3. TLC = FVC+RV
- 15. 1.Diagnostic: A.To evaluate symptoms,signs, and abnormal lab tests • Symptoms: dyspnea wheezing, orthopnea, cough, phlegm production, chest pain • Signs: diminished breath sound, over inflation, expiratory slowing, cyanosis, chest deformity, unexplained crackles • Abnormal lab test: hypoxemia, hypercapnia, abnormal chest radiograph B. To measure the effect of disease on pulmonary function
- 16. C. To screenindividuals at risk of having pulmonary disease Smokers Occupational exposure D. To assess preop risk prognosis( lung transplant) health ststus before begining of a strenous physical activity program
- 17. 2. Monitoring To assesstherapeutic intervention a) Bronchodilator therapy b) Steroid therapy (Asthma, ILD) c) Antibiotics in cystic fibrosis To describe the course of disease that affect lung function Pulmonary disease (obstructive airway disiese,ILD) Cardiac disease (CHF) NM disorders (GB syndrome)
- 18. To monitor peopleexposed to injurious agent To monitor adverse reaction to drug with known pulmonary toxicity 3.To identify Flow Volume Loop patterns 4. Disability/Impairment evaluation To assess patients as part of rehabilitation program To assess risk as a part of an insurance evaluation 5. Public Health: For clinical research
- 19. Due to increased myocardial demand 1.AMI within1WK 2. Hypo / severe hypertension 3. Ventr arrhythmia / non compensated HF 4. PAH / Acute corpulmonale Due to increased intracranial/intraocul ar/intrathoracic pressure 1. Cerebral aneurysm 2. Brain surgery 4wk 3. Eye surgery 1 wk 4. Pneumothorax 5. Thoracic/ abd sx 4wk 6. Late term pregnancy Infection controle issue 1. Active / transmissable resp inf (TB/covid) 2. Hemoptysis 3. Oral lesion/ bleed Should be discontinued if pt feels pain during procedure
- 20. In pulmfuntion lab, where operator are experienced enough, Emergency care can be given if needed Callibration of the device Quiet and calm env. Temp and barometric pressure is a important variable in PFT
- 21. Smoking within1 hr Consuming intoxicants before 8hr of test Vigorous exercise within 1 hr Tight clothes that interrupt chest and abd wall expansion freely
- 22. Seated erect Shoulder slightly back, Chin slightly up Chair without wheel with height adjustment Feet should be flat on the floor Nose clip or manual occlusion of nose should be used Test in standing position are more or less similar to sitting
- 23. Spirometry canbe a major source of infection as well as place of infection transmission Directly by : Mouthpiece, noseclip, chair arms Indirectly by : Aerosol droplet generation Avoide this risks by : Handwashing/sanitisation Use of disposable equipment where possible
- 25. 1. FEV1 andFVC manouver 2. Expiration only manouver 3. Bronchodialator responsive testing manouver (Reversibility test) 4. SVC (slow vital capacity) manouver
- 26. Equipment mustbe Calibrated Loosen tight fitting clothes Denture if they are loose better tobe removed Age, Weight, Height is recorded Explain the pt about the procedure Counsel that the procedure may not be comfortable
- 27. Maximum inspiration •Start at flowzero •Inspire as deeply as possible •No pause •Wait till the inspiration is complete ( eye brow becomes widened, head starts quivering) Blast of expiration • Don’t just blow, blow as much and as forcefully possible Continued expiration At least 6 sec is acceptable 3 sec for <10 yrs Wait for the plateau phase in display Ask for the next step Maximum inspiration after forced expiration •To return to TLC and complete the flow volume curve •This will cross check whether the pt began exp from full inspiration or not FEV1/FVC MANEUVER
- 28. Expiration only manouver (Donefor children only) Inspire maximum lung vol within 2 s Insert mouth piece Innitiate max expiration Remove mouth piece at end of forced expiration
- 29. Bronchodialator responsive test Degreeof improvement of air flow in response to bronco dilator Can differentiate Asthma from other COPD But neither asthma nor COPD is diagnosed on spirometry bronchodilator Dose FEV1 before and after Salbutamol 200-400mcg via large spacer 15 min Terbutaline 500 mcg via turbohaler 15 min Ipratropium 160 mcg via spacer 45 min
- 30. The test canbe concluded when both ACCEPTABILITY and REPEATABILITY criteria are met To ensure the REPRODUCIBILITY of the test Requires 5 to maximum 8 attempt
- 31. Free fromartefact ( Cough / Early glottis closure) Good start Free from leaks Extrapolation back from the PEFR gives a theoretical start time (should be within 5% of FVC or within 150 ml) Acceptable exhalation Adults :at least 6 sec of exhalation and plateue Children <10yrs : at least 3 sec of exhalation
- 32. Three acceptablemaneuvers (meeting above criteria) Two largest FVC measurements within 150 ml of each others Two largest FEV1 measurements within 150ml of each others
- 33. 1. FVC 2. FEV1 3.FEF 25-75 4. Change in FVC and FEV1 after broncho dialator use 5. Flow volume curve 6. Flow time curve
- 34.
- 36. Total volumeof air that can be exhaled forcefully from TLC The majority of FVC can be exhaled in<3 seconds in normal Often prolonged in Obstructive lung disease Measured in liters
- 37. 80-120% =Normal 70-79% = Mild reduction 50-69% = Moderate reduction <50% = Severe reduction
- 38. Volume ofair forcefully expired from full inspiration (TLC) in first second Normally 75-80% of FVC is exhaled in first second Thus FEV1/FVC can be utilised to characterise lung disease
- 39. Mean forced expiratoryflow during middle half of FVC May reflect effort independent expiration And the status of the small air way
- 41. >60% normal 40-60% mild obstruction 20-40% moderate obstruction <20% Severe obstruction
- 42. INTERPRETETION FVC alone doesnot make any sense unless and until we compare it with the time dimension i.e. FEV1 Main determinant of PFT is the FEV1/FVC FEV1/FVC (>80%) LOW Normal/high Always obstructive Restrictive
- 43. Obstructive 1. COPD (Emphysema/ Bronchiectasis/S AD) 1. ASTHMA 2.CF 3. BRONCHIOLITIS 4. BRONCHIECTASIS For expiration driving force >Air pressure Driving force = IPP + Elastic recoil pressure Elastic recoil pressure is low in obstructive ds That is why exp function (FVC) starts falling day by day Hyperinflation Air trapping FEV1 low Low FVC normal Low RV High High TLC (FVC+RV) High Remain unchanged
- 44.
- 45. Q. Can obstrlung dis have normal FEV1/FVC ? Yes, in Small air way disease. Here we diagnose SAD by FEF 25-75 /MMEFR/MEAN FORCED EXPIRATORY FLOW RATE It is the average flow rate of lung in middle 50% of the FVC manouver It is the slope of the line
- 46. Reversibility testby SABA If FEV1 > 12% and FVC > 200ml It indicates Bronchial Asthma
- 47.
- 49. Here lung’sinspiratory function is affected So IRV is decreased FVC= IRV + TV +ERV = FVC FEV1 remains normal more or less FEV1/FVC remains normal/high
- 51.
- 52. Restrictive Restrictive Extra parenchymal NM disorders (TLCLow Chest wall deformities Intra parenchymal DLCO normal DLCO low KCO normal
- 53. Intra parenchymal NM disorder Chestwall deformity DLCO LOW NORMAL TLC LOW LOW NORMAL RV LOW NORMAL RV/TLC HIGH NORMAL KCO (DLCO/VOL) NORMAL HIGH
- 54. It usesa small amount of CO to measure gas exchange across the alveolar membrane during a 10 sec breath hold. CO in exhaled air is analysed to determine the quantity of CO crossing the membrane
- 55. FACTORS INCREASD DLCODECREASED DLCO Thickness of alveolar membrane ILD smoking Altered volume/surface area ratio Emphysema Hb available Polycythemia Anaemia Pregnancy Blood coming to capilleris Pulmonary Hge Asthma Left to right shunt Exercise Pulmonary vascular disease
- 56. Diffusion limitedgas Affinity of Hb for CO is >200 times Partial pressure of CO in pulmonary capillaries rises very slowly KCO (Diffusion coefficient)= DLCO/ Lung Volume Normal in ILD Raised in Extra parencymal disease
- 57. Intra parenchymal NM disorder Chestwall deformity DLCO LOW NORMAL TLC LOW LOW NORMAL RV LOW NORMAL RV/TLC HIGH NORMAL KCO (DLCO/VOL) NORMAL HIGH
- 58. Different flow volloops NORMAL Scooped pattern Fixed airway obstruction Extra thoracic variable obstruction Intra thoracic variable obstr
- 59.
- 60. Narrowing ismaximal in Expiration As lesion is intra thoracic Intra thoracic pressure is maximum in expiration and lower than air Thus expiratory limb is flattened e.g. Tracheomalacia
- 61. Obstruction worsens ininspiration As negative pressure narrows trachea Thus Inspiratory limb flattens E.g extrinsic compression from Goiter, LN
- 62. Maximum airflowis limited to a similar extent in both inspiration as well as expiration Both limbs are affected E.g. Tracheal stenosis, FB
- 63. Most commoncause is poor patient technique Sub optimal inspiration Sub maximal expiratory effort Delay in forced expiration Shortened expiratory time Air leak around the mouth piece Poor posture = leaning forward Subjects must be observed and encouraged through the procedure
- 65.
- 66. Highly dependenton patient compliance and effort Thus FEV1 and FVC may be underestimated Not useful for <4years/unconcious/sedated Can not measure RV,FRC,TLC