![Lung capacities
• IC-max: amount of gas inspired in to the lungs
after a normal tidal exp: [IC=TV+IRV] 3500ml
• FRC-amount of gas remain in the lungs after
normal exp:[ FRC=ERV+RV] 2500ml
• VC-max: amount of gas expired from the lungs
after a max: insp: [VC=IRV+TV+ ERV] 4500ml
• TLC-max: amount of gas inspired to expand the
lungs to its max:extend [TLC=TV+IRV +ERV
+RV] 6000ml](https://image.slidesharecdn.com/pftugcims-250503042506-e68edb0c/85/Pulmonary-Function-Tests-Overview-CIMS-Bsp-29-320.jpg)
Pulmonary Function Tests Overview CIMS Bsp
- 1. Pulmonary Function Tests Dr. Pratik Kumar Assistant Professor Respiratory Medicine CIMS, Bilaspur
- 2. Introduction: • Pulmonary function tests (PFTs) are a group of tests that measure how well your lungs works, how well the lungs take in and exhale air, and how efficiently they transfer oxygen into the blood. • PFT or LFT are useful in assessing the functional status of the respiratory system both in physiological and pathological condition. • It is based on the measurement of volumes of air breathed in and out in normal breathing and forced breathing.
- 3. PFT helps to solve many Respiratory Problems Make or confirm Diagnosis Establish a prognosis Suggest treatment Monitor effects of treatment
- 4. Applications of PFT S. No. Applicatio n Sub division Particulars I Human Biology & Physiology Physiology Normal Function Changes with exercise, posture, barometric pressure, pregnancy etc. Physiological Anthropometry Relation to age , sex, size, ethnic group, customary activity, variation →diurnal , seasonal, climatic, geographical
- 5. Applications of PFT S. No. Applicatio n Sub division Particulars II Clinical Science Diagnosis Causes of wheeze, breathlessness, cyanosis, finger clubbing & aspects of respiratory failure Interpretation of abnormal chest X- ray Clinical assessment Diseases of lung, chest wall, heart & circulation Diseases of the central nervous system Accident involving the trunk Medical Treatment Oxygen therapy, bronchodilator therapy, assisted ventilation
- 6. Applications of PFT S. No. Applicatio n Sub division Particulars II Clinical Science Surgical Treatment Suitability for operation Anaesthetics Suitability for and management during & after an anaesthesia Research Applications Evaluation of remedies Relationship of deranged function to abnormal structure Assessment of Prognosis
- 7. Applications of PFT S. No. Applicatio n Sub division Particulars III Community Medicine Epidemiology Effects of smoking and air pollution Prevalence of respiratory impairment Identification of high risk cases Rehabilitation Capability for physical work IV Occupation al Medicine Health in Industry Pre-employment, periodic & exit examination, effects of respiratory hazards, suitability for strenuous work Establishment of safe conditions
- 8. Applications of PFT S. No. Applicatio n Sub division Particulars IV Occupationa l Medicine Diagnosis and assessment of occupational pulmonary diseases Asbestosis, beryllium disease, byssinosis, farmers lung, pneumoconiosis of coal workers and other occupational groups Lung disease in grain handlers, hard metal workers, silo fillers, those exposed to proteolytic enzymes, toluene, di-iso-cyanate, etc. V Medicine & the Law Assessment of disability Functions of the lungs and the capacity for exercise
- 9. 1. Breath holding test: Ask the patient to take a full but not too deep breath & hold it as long as possible. >25 SEC.-NORMAL Cardiopulmonary Reserve 15-25 SEC- LIMITED CardioPulmonary Reserve <15 SEC- VERY POOR CardioPulmonary Reserve (Contraindication for elective surgery) 25- 30 SEC - 3500 ml VC 20 – 25 SEC - 3000 ml VC 15 - 20 SEC - 2500 ml VC 10 - 15 SEC - 2000 ml VC 5 - 10 SEC - 1500 ml VC
- 10. 2. Single Breath Count: After deep breath, hold it and start counting till the next breath. Normal- 30-40 COUNT Indicates vital capacity
- 11. 3. SNIDER’S MATCH BLOWING TEST: Measures Maximum Breathing Capacity. Should take 6 attempts Ask to blow a match stick from a distance of 6” (15cms) with Mouth wide open Chin rested/supported No pursed lips No head movement No air movement in the room Mouth and match stick at the same level
- 13. Can not blow out a match • MBC < 60 L/min • FEV1 < 1.6L • Able to blow out a match • MBC > 60 L/min • FEV1 > 1.6L
- 14. 4. FORCED EXPIRATORY TIME: After deep breath, exhale maximally and forcefully & keep stethoscope over trachea & listen. Normal FET – 3-5 SECS. Obstructive Lung Disease - > 6 SEC Restrictive Lung Disease - < 3 SEC
- 16. 5. RESPIRATORY RATE • Essential yet frequently undervalued component of PFT • Imp. evaluator in weaning & extubation protocols • Increase RR ‐ muscle fatigue ‐work load ‐ weaning fails
- 17. 6. DE BONO’S WHISTLE BLOWING TEST: MEASURES PEFR. Patient blows down a wide bore tube at the end of which is a whistle, on the side is a hole with adjustable knob. As subject blows whistle blows, leak hole → is gradually increased till the intensity of whistle disappears. At the last position at which the whistle can be blown, the PEFR can be read off the scale.
- 19. 7. Wright ‘s Respirometer : Measures VT and minute volume (MV) Simple and rapid Instrument- compact, light and portable. Disadvantage: It under- reads at low flow rates and overreads at high flow rates. Can be connected to endo tracheal tube or face mask Prior explanation to patient is needed.
- 20. Contd… Ideally done in sitting position. MV- instrument record for 1 min. And read directly VT-calculated and dividing MV by counting Respiratory Rate. Accurate measurement in the range of 3.7- 20 L/min.(±10%) USES: 1) Bedside PFT 2) ICU – Weaning Pts. from Ventilator.
- 21. 8. Spirometry Measures Lung volumes and capacities.
- 22. 9. BED SIDE PULSE OXIMETRY 10. ABG
- 23. DIAGNOSTIC VALUE AND INTERPRETATION OF SPIROMETERY:
- 24. Spirometry • It is an instrument for measuring the air capacity of the lungs • Measurement of the pattern of air movement in and out of the lungs during controlled ventilatory maneuvers. • spirometre is used to measure the air flow, ventilatory regulation, ventilatory mechanics and lung volume during a forced expiratory maneuver from full inspiration.
- 25. INSTRUMENTS 1. Volume Displacement Type (Dry Rolling Seal Spirometers) 2. Flow Integrating Spirometers (Use Pneumotachometers) 3. Mechanical Flow Device (Use Turbine Transducers)
- 26. Dry Rolling Spirometers Highest Accuracy and Reproducibility Accuracy not affected by Humidity and Temperature
- 27. Lung volume and capacities • Lung vol: are the static vol. of air breathed by an individual, ie vol. of air present in lung under specific position of the torax • 4 lung volumes • Depends on age, weight, gender and body position • 2 or more vol. when combined are capacity
- 28. Lung Volumes • TV-the vol. of gas exchanged during a relaxed insp. followed by an exp: (500ml) • IRV-extra vol: of gas that can be inspired above tidal insp: 3000ml • ERV-extra vol: of gas that can be expired after a normal tidal exp: 1000ml • RV-vol: of gas remain in lungs after a forceful exp: 1500ml
- 29. Lung capacities • IC-max: amount of gas inspired in to the lungs after a normal tidal exp: [IC=TV+IRV] 3500ml • FRC-amount of gas remain in the lungs after normal exp:[ FRC=ERV+RV] 2500ml • VC-max: amount of gas expired from the lungs after a max: insp: [VC=IRV+TV+ ERV] 4500ml • TLC-max: amount of gas inspired to expand the lungs to its max:extend [TLC=TV+IRV +ERV +RV] 6000ml
- 30. Lung Volumes and Capacities
- 32. Lung Factors Affecting Spirometry • Mechanical properties • Resistive elements
- 33. Mechanical Properties • Compliance – Describes the stiffness of the lungs – Change in volume over the change in pressure • Elastic recoil – The tendency of the lung to return to it’s resting state – A lung that is fully stretched has more elastic recoil and thus larger/ maximal flows of gas
- 34. Resistive Properties Affected by: Lung volume 1.Age 2.Sex 3.Height 4.Weight 5.Race 6.Disease Bronchial smooth muscles
- 35. PFT procedure • Forced expiratory maneuver is the common clinical approach • Results are found in patients chart/moniter • Common spirometric values areFEV1 and FVC FEV1/FVC ratio • Lung volume and peak expiratory flow rate (PEF or PEFR) are measured to differentiate obstructive or restrictive problems • Forced expiratory flow (FEF)
- 36. Procedure • Sit up straight • Get a good seal around the mouth piece • Rapid inhale maximally • Without any delay blow out as hard as fast as possible (blast out) • Continue the exhale until the patient can`t blow no more • Expiration should continue at least 6sec (in adult) and 3 sec (children under 10yrs) • Repeat at least 3 technically acceptable times (without cough, air leak and false start)
- 37. Normal spirogram
- 38. How to interpret abnormal PFT • If FVC&FEV1 is less than 80% (total vol:of air expelling is approx: 80% with in 1sec ie; FEV1) • Suggestions of some pathology, at this point and can`t decide obstructive/ restrictive problem
- 39. Forced expiratory volume in 1 second (FEV1) • FEV1 is the volume of air that can forcibly be blown out in one second, after full inspiration. • Average values for FEV1 in healthy people depend mainly on sex and age height and mass. • Values between 80% and 120% are considered normal.
- 40. Forced vital capacity (FVC) • Forced vital capacity(FVC) is the volume of air that can forcibly be blown out after full inspiration.
- 41. FEV1/FVC ratio (FEV1%) • FEV1/FVC (FEV1%) is the ratio of FEV1 to FVC. In healthy adults this should be approximately 75–80%.
- 42. Forced expiratory flow (FEF) • Forced expiratory flow (FEF) is the flow (or speed) of air coming out of the lung during the middle portion of a forced expiration. • generally defined by fraction, The usual intervals are 25%, 50% and 75% (FEF25, FEF50 and FEF75)
- 43. Identify an obstructive problem • Obst: disorders (asthma, copd) air flow reduces because of narrowing of air ways • FEV1 is reduced • Spirogram is continued to 6 sec to empty lung, FVC also reduced because gas is trapped behind the obstructed bronchi • Cardinal feature of obstructive defect is reduction in the FEV1/FVC ratio
- 44. Contd… • In obstructive diseases (asthma, COPD, chronic bronchitis, emphysema) FEV1 is diminished because of increased airway resistance to expiratory flow. • The FVC may be decreased due to the premature closure of airway in expiration • This generates a reduced value (<80%, often 45%). 60-80% -mild 40-60% -moderate <40% -severe obstructions
- 47. Restrictive problem • Restrictive disorders can be cause by disease of the lung parenchyma (lung fibrosis) and chest wall disease(kyphoscoliosis) • This prevent the full expansion of the lungs therefore FVC may be reduced • FEV1 will increased because of the stiffness of the fibrotic lungs increases the expiratory pressure • Hence expired air comes out very quickly resulting with a high FEV1/FVC ratio
- 51. Interpretation of Spirometric Data LOW NORMAL FVC FVC NORMAL LOW LOW NORMAL OBSTRUCTIVE MIXED RESTRICTIVE NORMAL FEV1/FVC (absolute)
- 52. Reversibility Criteria Function Criteria PEF 71% FVC 15% FEV1 12% FEV1/FVC 17% FEF25-75 45%
- 53. Flow Volume Loop
- 54. Thanks