Ms Priya PattniClinical Physiologist

WDHB

Hamilton

8:30 - 9:25 WS #96: Lung Function Testing in Your Practice

9:35 - 10:30 WS #108: Lung Function Testing in Your Practice

(Repeated)

Lung Function in Your Practice

By Priya Pattni

Clinical Physiologist CRFS

Key points covered

• Spirometry in your practice, testing and interpretation

• Very brief discussion on how Spirometry should be performed

• Some case examples demonstrating different abnormality types

• When clinical question not answered by Spirometry, what other options in lung function

Spirometry Why?

• Employment Screening• Pre-employment medical• Monitoring• Weaning steroid meds• SOBOE• Query chronic cough• Abnormal CXR (hyper-inflated lung)• Diagnostics • Heart vs Lungs• Hyperventilation or genuine airflow limitation• Obstruction, restriction or both

Spirometry why not?

• Recent eye, thoracic or abdominal surgery• Recent MI (4weeks)• AAA • Hernia• Acute illness • Dementia• Untreated PE• Nausea • Dementia• Recent chest, neck or back injury

Spirometry – Patient prep

• Reason of testing – indication

• Brief explanation on how testing is required to be done, it is not a relaxed test.

• Medication list, if already taken any inhalers

• Check for any contra-indications, i.e. Brief medical history

Spirometry Testing 1

• Simple brief instructions, followed by prompts during testing in a timely manner.

• Deep breath in and blast out with no pause or hesitation, hard and fast

• Continuous encouragement to keep exhaling is very important

• Then take hard fast deep breath in before coming off the mouthpiece

Spirometry Testing

• Take a deep breath in..

• Without any pause blast out…

• And keep breathing out….

• Keep going until six seconds reached or patient unable to breath out any further.

• Encourage patient right through the trial…then take a deep breath in and catch your breath.

Phases of Spirometry

Acceptability 1

Slow start?

Acceptability 2

Acceptability 3

Acceptability 4

• Short blow with normal ratio and restrictive indication

Acceptability 5

Acceptability 6

• Same patient with much long breath out

Acceptability 7

Acceptability 8

Acceptability 9

Acceptability 10

Repeatability

Lung volumes

Airway network

Volume-Time Graph

Components of FV-Loop

• FV-Loop labelled with components

Components of FV-Loop

• FEV1: Forced expiratory volume in first second, is the volume of air exhaled forcefully in first second after maximal inhalation

• FVC: Forced Vital capacity, is the total volume of air exhaled forcefully until no more air can be expired

• FEV1/FVC%: AKA (FER) that is forced expiratory ratio. The FEV1 is presented as a percentage of FVC

• MMEF or FEF25-75%- Maximum Mid Expiratory Flow, decreased in obstructive lung disorders with a concaving pattern of the loop

Interpretation

Case 1

• Increasing SOBOE

• Hx working in building industry

• Occupational exposure, inhaler given with not much relief

• Spirometry ordered.

• Bloods and CXR pending

Case 1

Interpretation Guide

C. Look at the FVC C. Look at the FVC

Case 1

Case 1 cont..

Large airflow obstruction -Fixed

• Flattened expiratory and inspiratory components of loop

Case 2

• Increased SOBOE

• Hx of subglottic stenosis with polyps

• Increased symptoms over the last month

• Abs did not help

• ? Benefit from inhalers

• Ex 30pys

Case 2

Interpretation Guide

C. Look at the FVC C. Look at the FVC

Case 2

Interpretation Guide

C. Look at the FVC C. Look at the FVC

Case 2

Grading scale

Case 2

Case 3

• Patient increased SOB

• ? PAH

• possible MCTD?

• PFTs ordered

• Bloods pending

• Significant smoking Hx

• Nil inhalers

Case 3

Interpretation Guide

C. Look at the FVC C. Look at the FVC

Case 3

Interpretation Guide

C. Look at the FVC C. Look at the FVC

Case 3

Grading scale

Case 3

Extra-thoracic Obstruction

• Example VCD

Intra-thoracic Obstruction

Variable airflow Obstruction

Variable airflow Obstruction

Interpretation Guide

C. Look at the FVC C. Look at the FVC

Variable airflow Obstruction

Grading scale

Variable airflow Obstruction

Variable airflow Obstruction

Variable airflow Obstruction

Variable airflow Obstruction

Reversibility

Reversibility

Reversibility

Reversibility

Probable Restriction

Probable Restriction?

Erect/Supine

Erect/Supine

Spirometry normal but patient still symptomatic

• Dlco – Gas transfer using CO gas and He or CH4 gas for single breath volumes

• Body plethysmography – Static lung volumes

• Bronchial challenge tests – Can be direct or indirect agents egdirect Methacholine and Indirect Saline or Mannitol

• Erect Supine spirometry

• FeNO – Exhaled nitric oxide

Messages from Respiratory Consultants 1

• Dr Ron Hayudini (Waikato Hospital)

“Look Before you Leap….Always establish that the results are reliable before using them”

“Pre/post should be done even if pre is normal. For COPD dx you need post spirometry any way.”

Any comments on inhalers for COPD and asthma patients

“COPD – 1st line is LAMA, and in Asthma first line is ICS”

Messages from Respiratory Consultants 2

• Dr Paul Tan (Whangarei Hospital)

“Firstly, ensure spirometry done is technically adequate.”

“ Secondly, if pre is abnormal do a post. Should do post if pre is normal, depending on what is the clinical question. Always use results in clinical context, know what the question is know what you are looking for. ”

Messages from Respiratory Consultants 3

• Dr Christine Bradley (Whangarei Hospital)

• “Do bronchodilator spirometry even if baseline is normal, post BD done to excluded the reversibility component , as sometimes there can be significant reversibility.”

Messages from Respiratory Consultants 4

• Dr Janice Wong (Waikato hospital) “A negative response to pre/post bronchodilator spirometry does not exclude Asthma, especially when the patients are exacerbated or wheezy”

Summary

• Detect

• Diagnose

• Follow up

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