Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Pulmonary function test in children (spirometer)

Pulmonary function test in children (spirometer)

Related Books

Free with a 30 day trial from Scribd

See all
  • Be the first to comment

  • Be the first to like this

Pulmonary function test in children (spirometer)

  1. 1. • Respiratory diseases account for the majority of all paediatric hospital visits and hospitalizations all over the world, with significant morbidity and mortality. • Children have a dynamic developmental phase during which lung volume size and airway size change with increasing age. Introduction
  2. 2. Introduction • Spontaneous breathing is defined as movement of air into and out of the lungs as a result of work done by an individual’s respiratory muscles. • The air that we breathe contain approximately 21% oxygen.
  3. 3. What you can control in Ventilation • Volume V : how much air will get in and out of patient. • Pressure P: how much pressure will get in and out of patient . • Rate R.R: how fast the patient will breath? Breath min • Flow rate F.R: Flow = Volume Time. How fast the patient will push the volume in & out. • Oxygen O : how much oxygen the patient will put in.
  4. 4. Lung volumes and lung capacities • Lung volumes and lung capacities refer to the volume of air associated with different phases of the respiratory cycle. • Lung volumes are directly measured; • Lung capacities are combination of two or more lung volumes
  5. 5. Lung volumes • Static Lung volumes: volumes & capacities • Depend on Expiration & inspiration but not on the rate. • Dynamic lung volumes: volume& velocity • Are the one that are depend on the rate at which they happen.
  6. 6. Lung volume • Four types • 1. Tidal volume • 2. Inspiratory reserve volume • 3. Expiratory persevere volume • 4. Residual volume
  7. 7. Tidal volume Normal volume of air inspired or expired during quiet breathing (500 mL in males and 400 mL in females )TV = 5-8cc/kg Inspiratory reserve volume Extra volume of air inhaled after tidal volume by max inspiratory effort (3000 mL in males and 2100 mL in females) 20‐25 ml/kg Expiratory persevere volume Extra volume of air that can be exhaled after tidal volume by max expiratory efforts (1100 mL in males and 800 mL in females) Residual volume Volume of the air left out in lungs after forceful expiration or complete expiration (1200 in a normal adult, 20‐25 ml/kg)
  8. 8. Lung capacities • These are combinations of two or more lung volumes • 1. Inspiratory capacity • 2. Functional residual capacity • 3. Vital capacity • 4. Total lung capacity
  9. 9. Inspiratory capacity Max volume of air that can be inspired after normal tidal expiration IC = TV+IRV Functional residual capacity Volume of air remaining in lungs after normal tidal expiration (FRC= ERV + RV) Vital capacity Max Amount of air expelled after deepest possible inspiration (VC = TV+IRV+ERV) Total lung capacity Volume of air present in lung after max inspiration ( TLC = VC + RV )
  10. 10. Dynamic lung volumes • Forced vital capacity or FVC • The forced expiratory volume in 1 second (FEV1) • Peak expiratory flow rate (PEFR) • forced expiratory flow at 25-75
  11. 11. Forced vital capacity or FVC is volume of the air that can be expired rapidly with max force following a max inspiration, and its timed by a spirograph. The forced expiratory volume in 1 second (FEV1) is the volume of air (in liters) exhaled in the first second during forced exhalation after maximal inspiration. Normally, at least 80% of the forced vital capacity (FVC) is exhaled in the first second. Peak expiratory flow rate (PEFR) is the maximum flow rate generated during a forceful exhalation, starting from full lung inflation. forced expiratory flow at 25-75% the average flow rate measured over the middle half of the expiration.
  12. 12. Pulmonary function tests (PFTs) • noninvasive tests that show how well the air ways & lungs are working. • The tests measure lung volume, capacity, rates of flow, and gas exchange. • PFT can be done with two methods. • Spirometry. • Plethysmography.
  13. 13. Spirometry • Spirometry is a simple test used to help diagnose and monitor certain lung conditions by measuring how much air you can breathe out in one forced breath. • It's carried out using a device called a spirometer, which is a small machine attached by a cable to a mouthpiece.
  14. 14. • Spirometry parameters are influenced by weight, height, age, sex, environmental factors, ethnicity, patient cooperation and effort, and technical factors. • Most children are able to perform good quality spirometry/flow volume loops from 5 years of age.
  15. 15. • Although it is not difficult to perform spirometry in children in the primary care office setting. • it is frequently underused in the paediatric age group. • A published survey revealed that only half of physicians in paediatric primary care who were treating children with asthma were using spirometry and nearly half did not interpret the spirometry results correctly.
  16. 16. Indications for spirometry in children • Spirometry is commonly indicated for children with chronic cough, persistent wheezing, and for the diagnosis and monitoring of asthma and cystic fibrosis. • Reviewing asthma control and disease activity. • It is frequently used to measure lung function in a number of diseases that affect the lungs including haematological disorders such as transfusion- dependent thalassaemia majorand sickle cell anaemia, haemato-oncology conditions, connective tissue disorders, ataxia telangiectasia, and chest deformities such as pectus excavatum. • Spirometry is helpful in ascertaining preoperative lung function in flaccid neuromuscular scoliosis (e.g. muscular dystrophy, spinal muscular atrophy, and cerebral palsy).
  17. 17. Contraindications to spirometry • Although there is no absolute contraindication for spirometry, • the following conditions are considered relative contraindications: • presence of respiratory tract infection (e.g. influenza), • haemoptysis of unknown origin, • pneumothorax, • uncontrolled hypertension, • recent thoracic, abdominal, eye surgery • nausea, vomiting or pain, • confusion or dementia
  18. 18. Preparing for the test • The patient should avoid strenuous exercise or eating large meals for a few hours before the test. • It's best to wear loose, comfortable clothing on the day of the test. • If the child use bronchodilator medication ,you may advice to stop using it beforehand.
  19. 19. What happens during a spirometry test • The patient will be seated during the test and a soft clip will be placed on his nose to stop air escaping from it. • The tester will explain what you need to do, and you may be asked to have a few practice attempts first. • When you're ready for the test, you'll be asked to: • inhale fully, so your lungs are completely filled with air • close your lips tightly around the mouthpiece • exhale as quickly and forcefully as you can, making sure you empty your lungs fully • blowing out candles on a cake : The instructions should be “take in a deep breath and blow, blow, blow…” until the test is completed. • This will normally need to be repeated at least 3 times to ensure a reliable result. • producing results within less than 5% error.
  20. 20. Spirometer VS Plethysmograph • Spirometer can measures all volume & capacities except : • Residual volume • Total lung capacity • Functional residual capacity
  21. 21. Predicted Normal Values • Reference values for spirometry are derived from studies of specific populations of healthy people like National Health and Nutrition Examination Survey. • Predicted : what the patient should have depending on Age, Hight, Sex, Weight & ethnicity.
  22. 22. Spirometer results • When performing PFT , three measures will reported: • Actual : what the patient performed • Predicted : what the patient should have depending on Age, Hight, Sex, Weight & ethnicity. • % predicted : a comparison of the Actual value to the Predicted value
  23. 23. Normal Spirometry • In general, parameters above 80% of predicted (and an FEV1/FVC ratio >80%) are considered normal results.
  24. 24. Loops & Curves • Flow-Volume Loops: flow-volume loop will show the vital capacity on the horizontal axis and the peak flow on the vertical axis. The slope of the curve is an indication of the expiratory flows. • FEV1 : can be determined from the volume-time curve.
  25. 25. • Flow-Volume Loops: • The flow-volume loop must be examined to ensure the validity of the test. • It should rapidly rise to a sharp peak, have a smooth expiratory curve, and not terminate until full exhalation has been achieved. • Cough, sudden termination of exhalation, and uneven expiratory effort are common errors seen in flow-volume loops.
  26. 26. Obstructive airway vs Restrictive lung disease
  27. 27. Obstructive Lung Disease • Obstructive lung disease is characterized by decreased airflow, as measured by FEV1 and FEF25%–75%. • The FVC is usually normal in mild disease, but with more severe disease, air trapping causes the vital capacity to decrease as the residual volume increases. • if the ratio of FEV1/FVC ratio is less than 80%, obstructive lung disease is present. • When the FEV1 and FEF25%–75% are diminished, the flow-volume loop will have a scooped out appearance because of lower flow rates . • Obstructive lung conditions other than asthma include chronic obstructive pulmonary disease, bronchiolitis, bronchiectasis, cystic fibrosis, congestive heart failure, sarcoidosis, or pulmonary embolism.
  28. 28. Bronchodilator Response • In general, an increase in FEV1 of greater than 12% (for low lung volumes, minimum change of 200 mL) and/or an increase in FEF25%–75% of greater than 20% is considered a significant positive response to a bronchodilator.
  29. 29. Restrictive Lung Disease • The defining characteristic of restrictive lung disease is decreased lung volume. • The FVC decreases, whereas the measures of airflow, FEV1, and FEF25%– 75% are preserved. The key to recognition may lie in the ratio of FEV1/FVC, which increases as the denominator (the FVC) decreases. • In addition, severe restriction will make all parameters decrease, except the FEV1/FVC ratio. • The flow-volume loop retains its normal shape but becomes smaller as the vital capacity diminishes. • Examples of restrictive lung diseases include muscular dystrophy, scoliosis, pulmonary fibrosis, and other types of pneumoconiosis.
  30. 30. Vocal Cord Dysfunction Syndrome • Vocal cord dysfunction is a condition in which a patient attempts to inhale against partially or totally closed vocal cords, resulting in inspiratory obstruction. • This results in flattening of the lower (inspiratory) limb of the flow-volume loop. • Vocal cord dysfunction is often misdiagnosed as asthma, with which it is often comorbid. • It occurs as the result of paradoxical closure of the vocal cords on inspiration, which produces stridor, dyspnea, and noises that are often misinterpreted as wheezing.
  31. 31. Comparison of Test Results • The usual convention for defining significant change between test results is to have measured volumes (FVC and FEV1) change by more than 10% and FEF25%–75% by 20% to 30%
  32. 32. Evidence-Based Summary • Multiple research studies have provided evidence indicating that as hypertension is managed by measuring blood pressure regularly and diabetes is managed by checking blood glucose levels, so should lung diseases should be managed by performing spirometry in capable patients.
  33. 33. THANKS FOR YOUR ATTENTION

    Be the first to comment

Pulmonary function test in children (spirometer)

Views

Total views

102

On Slideshare

0

From embeds

0

Number of embeds

0

Actions

Downloads

2

Shares

0

Comments

0

Likes

0

×