Interpreting Spirometry. Vikki Knowles BSc(Hons) RGN Respiratory Nurse Consultant G & W`CCG

Transcription

1 Interpreting Spirometry Vikki Knowles BSc(Hons) RGN Respiratory Nurse Consultant G & W`CCG

2 Why Spirometry? supports diagnosis classifies defect - obstructive/restrictive assesses -severity of defect - response to treatment - suitability for anaesthesia monitors progress

3 Lung Volumes

4 What is spirometry? measures volume of air expelled from lungs after maximal inspiration Without regard to time -relaxed vital capacity VC As a forced manoeuvre -forced vital capacity FVC -forced expiratory volume in 1 second FEV 1

5 Pre Test Considerations

6 Contraindications? Haemoptysis of unknown origin Pneumothorax Unstable cardiovascular status Thoracic, abdominal or cerebral aneurysms Recent eye surgery Recent thoracic or abdominal surgery

7 Before you start Check..

8 A reliable result 3 x forced manoeuvres Best 2 within 5% and 100 ml of each other The curve should be smooth and free of irregularities The curve should reach a plateau

9 Rejecting results Second breath Early termination of effort Inadequate inspiration Poor seal around mouthpiece Slow start to expiration Coughing, vocalising, puffing cheeks Leakage, nose, tube, bellows Early termination of the blow (<3secs) Submaximal effort Obstructing mouthpiece by tongue or false teeth

10 Normal values FEV1 > 80% predicted (Measured FEV1/Predicted X 100) FVC > 80% Predicted (Measured FVC/Predicted x 100) FEV1/FVC ratio > 70% or LLN (Measured FEV1/Measured FVC x100)

11 Predicted Values Europe Cogswell, Solymar, Zapletal (1975) 6-17 years, ECCS (1993) years.

12 Normal Spirometric curve FEV1%FVC = (4.05 x 100)/4.85= 83.5%

13 Peter Age 30 Symptoms Nocturnal breathlessness Wheeze SOBOE Hypersomnolence

14 Peter (2) PMH Possible asthma Morbid Obesity Family history Mother and brother asthma Drug Treatment Salbutamol prn Social History Non smoker Taxi driver

15 Peter (3) PEFR 520 FEV (77%) FVC 3.44 (80%) FEV1% 79% SpO2 98% CXR Lung fields clear

16 Normal FEV1 and VC with SOB,? Dyspnoea in this group should be investigated fully Most Patients - Exercise Induced Asthma Alveolitis Diffuse Pulmonary Fibrosis Heart Disease Pulmonary Thromboembolism Neurological/Metabolic causes

17 Obstructive Disorder Lumen of airway affected by Inflammation Bronchoconstriction Excessive mucous production Asthma COPD Bronchiectasis

18 Obstructive Picture

19 Ann History 54 yr old female Breathless for several years Ex smoker of 2 months 40 pack years No FH atopy Farmer s wife Breathless at night

20 Ann Symptoms and medication SOBOE Productive cough 3 courses antibiotics and prednisolone last 12 months MRC Dypnoea 3 Bilateral mild ankle oedema On Salbutamol and Beclometasone

21 Ann Investigation results On chest auscultation: wheeze, no crackles CXR NAD, heart size normal O 2 saturations 93% on air at rest PFTs Echocardiogram: NAD FBC: Normal

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23 Reversibility Testing

24 Treatment Add LABA/LAMA combination Continue salbutamol prn Discontinue beclometasone consider combination LABA/ICS if continued exacerbations Pulmonary Rehabilitation Self Management Plan

25 Result Feels well Able to help with work on the farm more fully again

26 Severity COPD

27 Restrictive Disorder Ability of the lungs to expand affected by Inflammation/fibrosis/scarring Rib cage deformity Muscular or neuromuscular weakness Fibrosis Pneumoconiosis Kyphoscoliosis Ankylosing spondylitis Polio Surgery

28 Restrictive picture

29 Brian Symptoms Shortness of breath for 2 months Dry Cough

30 Brian PMH Nil of note Childhood illnesses Drug Tx None FH Father Ca Lung Social Hx Ex smoker (12 pack years) Retired garage mechanic

31 Brian O/E: Fine end inspiratory crackles CXR: Patchy shadowing mid and lower zones

32 Combined defect Features of obstructive and restrictive defect Cystic fibrosis Severe COPD

33 Combined picture

34 Combined picture

35 Calculations % of predicted Measured x 100 Predicted FEV 1 /FVC ratio FEV 1 x 100 FVC % Difference Difference x 100 Highest value Eg 1.2 x 100 =33% 3.6 Eg 2.7 x 100 =75% 3.6 Eg PF220 increases x 100 =35% 310

36 Interpretation