INTERPRETATION OF PULMONARY FUNCTION

TESTS

A.A. Eldawlatly dawlatly@ksu.edu.sa

INDICATIONS

Is a basic tool to evaluate the patient respiratory status.

It is often the first diagnostic test employed in the work up.

Used for preoperative evaluation. Used for managing patients with known

pulmonary disease. Used to quantify pulmonary disability.

Requirement for Good PFTs

Adequate equipment Reproducible performance

AMERICAN THORACIC SOCIETY (ATS) GUIDELINES FOR ACCEPTABILITY & REPRODUCIBILITY

Criteria for acceptability Lack of artifacts Satisfactory start without hesitation Satisfactory exhalation with 6 sec of smooth

continuous exhalation

Criteria for reproducibility Largest FVC within 0.2L of next largest FVC Largest FEV1 within 0.2L of next largest FEV1 If the two above not met, additional spirogram

should be obtained

Variable effort, cough, early glottic closure can be seen on the graph but not at the values of the FEV1 and FVC

INTERPRETING SPIROMETRYNormal flow/volume Normal volume/time

AcceptabilityAcceptability

OBSTRUCTIVE LUNG DISEASE

FEV1 reduced more than FVC with FEV1/FVC ratio <70-80%.

FEV1 >80% Normal 60-80% mild obstruction 50-65% moderate

obstruction <50% severe obstruction

Example of spirometry with mild obstruction

Variable Means Predicted %Pred

FVC 2.63 3.11 84

FEV1 1.58 2.28 69

FEV1/FVC 60 73 -

FEF25-75% 0.59 3.56 23

PEF 4.9 5.78 85

RESTRICTIVE LUNG DISEASE

Both FEV1&FVC reduced proportionately FEV1/FVC normal or elevated Example: Variable Means Predicted

%Pred FVC 0.96 2.75 35 FEV1 0.94 1.90 49 FEV1/FVC 98 69 - FEF25-75% 2.25 2.11 107 PEF 2.98 5.40 55

UPPER AIRWAY OBSTRUCTION (UAO)

Types1. Variable extra thoracic obstruction (VEO):

inspiratory stridor, vocal cord paralysis, tracheomalacia.

2. Variable intra thoracic obstruction (VIO): expiratory stridor, tracheomalacia, neoplasm

3. Mixed: tracheal stenosis, foreign body or neoplasm

Mediastinal mass

Lack artifacts, start without hesitation, exhalation for 6 sLack artifacts, start without hesitation, exhalation for 6 s

Examples

Example 1

Variable means predicted %pred FVC 2.62 2.82 93 FEV1 1.45 1.98 73 FEV1/FVC 55 70 FEF25-75% 0.43 2.20 20 PEF 4.50 5.48

82

Example 2

Variable Means Predicted %pred

FVC 2.20 2.58 85

FEV1 1.79 1.85 97

FEV1/FVC 81 72

FEF25-75% 1.82 2.23 82

PEF 5.67 5.20 109

Example 3

Variable Means Predicted %pred

FVC 5.08 4.94 103

FEV1 2.66 3.58 74

FEV1/FVC 52 72

FEF25-75% 1.40 3.47 40

PEF 6.49 9.10 71

Example 4

Variable Means Predicted %pred

FVC 1.85 4.60 40

FEV1 0.92 3.33 28

FEV1/FVC 50 72

FEF25-75% 0.28 3.28 9

PEF 3.82 8.55 45

Example 5

Variable Means Predicted %pred

FVC 2.78 2.75 101

FEV1 1.90 1.90 100

FEV1/FVC 69 69

FEF25-75% 0.95 2.35 40

PEF 4.82 5.45 88

Example 6

Variable Means Predicted %pred

FVC 2.78 2.75 101

FEV1 1.90 1.90 100

FEV1/FVC 69 69

FEF25-75% 0.95 2.35 40

PEF 4.82 5.45 88

Example 7

Variable Means Predicted %pred

FVC 3.66 4.39 83

FEV1 1.03 2.87 36

FEV1/FVC 28 65

FEF25-75% 0.33 2.48 13

PEF 4.29 8.33 52

Example 8

Variable Means Predicted %pr

FVC 3.66 3.54 103

FEV1 2.30 2.77 83

FEV1/FVC 63 78

FEF25-75% 2.15 4.20 51

PEF 2.39 6.25 38

Example 9

Variable Means Predicted %pred

FVC 3.66 3.54 103

FEV1 2.30 2.77 83

FEV1/FVC 63 78

FEF25-75% 2.15 4.20 51

PEF 2.39 6.25 38

Example 10

Variable Means Predicted %pred

FVC 4.09 4.25 96

FEV1 1.95 2.88 68

FEV1/FVC 48 68

FEF25-75% 0.48 2.65 18

PEF 6.27 8.06 78

Example 11

Variable Means Predicted %pred

FVC 1.40 2.48 56

FEV1 0.85 1.75 49

FEV1/FVC 61 74

FEF25-75% 0.37 2.11 18

PEF 1.30 5.10 25

Example 12

Variable Means predicted %pred

FVC 3.02 3.41 88

FEV1 1.23 2.53 49

FEV1/FVC 41 74

FEF25-75% 0.41 2.77 15

PEF 3.95 6.10 65

THANK YOU