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Lung and Sleep

Lung Function Test (PFT)

Lung function tests or Pulmonary function tests (PFT’s) are non-invasive tests that show how well the lungs are working. They involve breathing in and out of a mouthpiece on a machine with different techniques at maximal effort.

There are a number of different lung function tests that measure different aspects of lung function. Respiratory medication including Puffers may need to be withheld for certain times for some tests.

At Heart of Melbourne Lung and Sleep we can test patient's from 8 years old. Tests available include:

Spirometry - determines the lung volume and partial volumes including inspiratory and expiatory vital capacity VC and Slow vital capacity and Forced vital capacity. Spirometry is performed before and after bronchodilator for assessment of reversibility of airflow obstruction. 


DLCO - Single Breath Diffusion is a non-invasive method to measure the diffusion capacity and the volumes of the lung to assess gas exchange/alveolar membrane integrity.

Bronchial Provocation Testing -  assists with diagnosis of asthma or assessment of the effectiveness of asthma treatment.

Mannitol Challenge Testing - is the most common bronchial provocation test. It is used to identify airway hyper-responsiveness to assist in the diagnosis of asthma. 

Maximal Respiratory Pressures – provide an indication of global respiratory muscle strength for both inspiration and expiration.

Contraindications for Lung Function Testing

Lung function testing requires the patient to sit unaided and follow specific instructions with maximal effort.

  • Patient’s with poor cognitive function may have difficulty performing the test

  • Patient’s with limited English may need an interpreter – please document on the referral if an interpreter will be required


The following are considered absolute contraindications to testing:

  • Acute myocardial infarction within 1 week

  • Systemic hypotension or severe hypertension

  • Significant atrial/ventricular arrhythmia

  • Noncompensated heart failure

  • Uncontrolled pulmonary hypertension

  • Acute cor pulmonale

  • Clinically unstable pulmonary embolism

  • History of syncope related to forced expiration/cough

  • Cerebral aneurysm

  • Brain surgery within 4 weeks

  • Recent concussion with continuing symptoms

  • Eye surgery within 1 week

  • Sinus or middle ear surgery or infection within 1 week

  • Presence of pneumothorax

  • Thoracic surgery within 4 weeks

  • Abdominal surgery within 4 weeks

  • Late-term pregnancy

  • Active or suspected transmissible respiratory or systemic infections

  • Influenza

  • Gastroenteritis (> 48hours without symptoms)

  • Physical conditions predisposing to transmission of infections, such as haemoptysis, significant secretions or oral bleeding

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Sleep Study


If there’s no obvious reason for your sleep problems or your doctor suspects you have a sleep disorder such as sleep apnea or narcolepsy, they’ll refer you to have an evaluation by a sleep specialist at a sleep clinic.

You will be fitted with the Home Based Sleep Study unit. This appointment will take approximately 30 minutes. You will need wear the device overnight which will monitor your breathing, brain activity, heart rate and body movements. You will return the monitoring device on the next day.

To get to the bottom of how severe your sleep issues are, your doctor may score you with a test called the Epworth Sleepiness Scale (ESS). The ESS is a scientifically validated questionnaire that is used to evaluate daytime sleepiness.

The ESS asks you to rate your likelihood of falling asleep while engaged in eight different activities. These activities might include watching television, reading a book, attending a meeting, or driving.

Sleep doctors and sleep technicians can determine whether you have certain types of sleep disorders by evaluating disturbances in your sleep cycle.

Your sleep cycle is divided into two phases:

  1. Phase 1: Non-Rapid Eye Movement (NREM) sleep is composed of 3 stages, varying from light to deep sleep.

  2. Phase 2: Rapid Eye Movement (REM) sleep is composed of a single-stage when dreaming occurs and eyes move rapidly in response to dreaming.

One full sleep cycle takes 90 minutes to complete and will repeat throughout the night. Your polysomnography can monitor your sleep cycle through each sleep stage in real-time by evaluating the specific brain wave signature for each stage.

Most people undergo an in-depth sleep study is called polysomnography. A polysomnography study records your brain activity in real-time. This allows a trained polysomnography technician to track the quality of your sleep and look for problems that may show the presence of sleep disorders. Polysomnography measures the quality of your sleep by identifying when you sleep, how much you sleep, and if there are any disturbances in your sleep cycle.

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At Heart of Melbourne we bulk bill all eligible investigations including lung function test and sleep study.

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