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Respiratory Laboratory


The Respiratory & Sleep Laboratory at Cork University Hospital opened in 1982 and was then known as the Pulmonary Function Laboratory. A Sleep Diagnostic Service s introduced in 1998 and the name was changed to the Respiratory & Sleep Laboratory to reflect this change in service provision. 


Services Provided by the Respiratory & Sleep Laboratory


  1. Pulmonary Function Tests
  2. Cardio-pulmonary exercise testing. 


Meet The Team

The Respiratory & Sleep Laboratory is staffed by two Respiratory Scientists. Ms Maria Stack is the Senior Respiratory Scientist. Maria began her career at CUH in 1987 and has overseen many changes in the service since then including the introduction of the Sleep Service in 1998 and the refurbishment and expansion of the Lab in 2009 to provide Cardiopulmonary Exercise Testing. Maria received her qualification as a Respiratory Scientist from DIT Kevin St where she was also awarded the Siemans Award in Medical Physics Physiological Measurement. In 2007 she obtained an MPhil from DIT for her Research Thesis on Sleep Apnoea. She also holds a Diploma in Asthma Care and has completed many short courses in Respiratory Medicine & Sleep during her time in CUH. 

The Respiratory & Sleep Laboratory also takes students on clinical placement from the BSc in Clinical Measurement at DIT Kevin St.


Contact Us

Location: Out-Patient Corridor, Phone: (021) 4922442

Opening Hours: Mon-Fri 9am-5pm

Services provided on Consultant Referral by appointment only.


Pulmonary Function Tests

Patients may be referred for Pulmonary Function Tests for a variety of reasons including:

  • To assist in the diagnosis of respiratory disease
  • To monitor response to treatment
  • Assessment of pulmonary disablement for occupational injuries
  • To monitor the progression of disease
  • Pre operative assessment of respiratory function
  • To assess the respiratory involvement in systemic diseases
  • Monitor drug toxicity in chemotherapy patients.
  • Detection of organ rejection post transplant. 

As CUH is a large teaching hospital encompassing more specialities than any other hospital in the country therefore there are several reasons why patients may be referred to Pulmonary Function Testing. The specialities referring include:


  • Respiratory.

The respiratory department refers patients with a variety of respiratory illnesses including: Asthma, COPD, Pulmonary Fibrosis, Sarcoidosis, Pulmonary Hypertension. CUH is a designated centre for Cystic Fibrosis and all patients are seen regularly for PFT’s. Many patients attending the hospital Pulmonary Rehabilation program are also referred. Cardiothoracic surgery – pre operative assessment for Thoracic and Cardiac surgery

  • General surgery – pre operative assessment on patients with co-existing respiratory illnesses
  • Onocology – pre and post chemotherapy to monitor drug toxicity
  • Radiotherapy – post-radiation effects on lung function.
  • Haematology – pre and post bone marrow transplant to detect rejection
  • Rheumotology – assessment of respiratory involvement in systemic illness e.g. SLE, Rheumotid Lung and monitoring drug toxicity for patients on Metotrexate.
  • Cardiology – outrule respiratory cause for breathlessness and monitoring side affects of the antiarrhythmic drug Amiodarone.
  • Neurology – assessment of respiratory effects of diseases of muscular weakness.
  • Nephrology – assessment of respiratory effects of renal failure.


The Pulmonary Function Tests Provided at CUH Include:


Bronchodilator Response

Lung Volumes by Body Plethysmography & Helium dilution

Gas Diffusion (DLCO)

Maximum inspiratory & expiratory Muscle strength testing

Bronchial Challenge (Methacholine, Mannitol & Exercise)

Cardiopulmonary Exercise testing (CPET)

Skin Allergy Testing


Spirometry Spirometry is a measurement of forced expiration. The patient inhales maximally, filling his or her lungs to Total Lung Capacity, and then exhales forcefully into a device called a spirometer. The spirometer measures volume and time, and from this several important parameters may be calculated:

    • FVC (Forced Vital Capacity): the maximum amount of air able to be exhaled on a single breath
    • FEV1 (Forced Expired Volume in 1 Second): the amount of air exhaled in the first second
    • FEV1/FVC: the percentage of the FVC exhaled in the first second


Bronchodilator Spirometry, repeated after the administration of a bronchodilator (most often Ventolin]). Generally, an increase of more than 12% in FEV1 is considered significant.


Gas Diffusion (DLCO) The single breath diffusing capacity, or DLCO, is a measure of the ability of the lungs to diffuse oxygen into the bloodstream. The test is performed by having the patient complete the following steps:

  1. expire all the way to Residual Volume
  2. inspire all the way to Total Lung Capacity, breathing from a supply of test gas
  3. hold breath for ten seconds
  4. expire forcefully 

The concentrations of certain gases present in the "test gas" is measured prior to the test. The initial portion of the final expirate is discarded, and a portion of the remainder is analyzed. Generally, the difference between the concentrations present before the breathhold and after the breathhold indicates the amount of gas that diffuses through the lungs and into the bloodstream


Helium Dilution Lung Volumes This test measures the total amount of gas in the lungs after a complete inspiration. The patient is connected to a spirometer containing a known concentration of helium. Initially, the gas in the patient's lungs dilutes the helium present in the system, and the helium concentration falls rapidly. After a few minutes, however, the patient and the spirometer equilibrate, and the helium concentration reaches a steady value. By measuring the initial and final concentrations of helium present, and by knowing the volume of the spirometer, the amount of gas in the patient's lung at the start of the test may be calculated.


Body Plethysmographic Lung Volumes This test measures the same things as does Helium Dilution Lung Volumes, but in a very different way. The patient sits in a clear rigid chamber, breathing through a valve. At some point in the breathing cycle, the valve is closed for a few seconds and the patient is asked to pant (although no breathing will occur since the valve is closed). Each time the patient tries to pant out, the gas in the lungs is decompressed slightly and the gas in the box surrounding the patient is compressed slightly. When the patient tries to pant in, the opposite occurs. By measuring the pressure changes in the lungs and in the box, the amount of gas in the patient's lungs may be calculated.


Methacholine Challenge In a Methacholine Challenge, a patient performs repeated spirometry tests following inhalation of increasing concentrations of the bronchoconstrictor methacholine.  In some patients with hypersensitive airways, methacholine may cause a change in airways function which is detected by the spirometry testing.  Those patients with a significant decrease in FEV1 following inhalation of methacholine will have a positive test result.  Following this test, patients are given a bronchodilator to reverse the bronchoconstriction.  This test may be helpful in evaluating unexplained cough or possible asthma. This test can only be ordered by a Respiratory Consultant. 


Maximal Inspiratory /Expiratory Muscle Strength

This is a test of respiratory muscle strength.  In one part of the test, the patient is asked to attempt to inhale as forcefully as possible against a tube.  In the other part of the test, the patient is asked to attempt to exhale as forcefully as possible against a blocked tube.  In both cases, the pressure the patient generates while attempting to inhale or exhale is recorded.  This pressure is correlated with the overall strength of the breathing muscles and may be helpful in assessing possible respiratory muscle weakness.



The CPET is a unique investigation that provides clinical information about a patient’s functional capacity and dyspnea which cannot be obtained from any other test.

Patients with exercise intolerance or dyspnea which remains unexplained after resting pulmonary function testing, cardiac stress testing, and echocardiography are may be sent for a Cardiopulmonary Exercise Tests (CPET). This is useful to determine whether the limiting factor is heart disease, lung disease, obesity or deconditioning. Using an incremental, symptom-limited protocol, patients are exercised to their maximal capacity on a treadmill. During the test, ECG, blood pressure and oxygen saturation is monitored and composition of inhaled and exhaled gases are measured and analyzed to estimate gas exchange, oxygen consumption, carbon dioxide output and ventilatory efficiency.

Other indications for a CPET include:

  • Pre-operative pulmonary evaluation prior to lung resection surgery, lung volume reduction surgery for emphysema and other major surgeries
  • Exercise prescription for pulmonary rehabilitation
  • Evaluation for lung transplants 

Currently a CPET may only be ordered by a Respiratory Consultant in CUH.