See also
A cardiopulmonary exercise test measures how the heart, lungs and muscles respond to exercise.
Before a CPET, the patient will have electrodes stuck to their chest and a cuff placed on one arm, to monitor their heart. They will also wear a face-mask which will monitor their breathing. During a CPET, the patient will be asked to cycle on a stationary exercise bike, so that the equipment can monitor how well the heart and lungs respond to exercise. After about 10 minutes you’ll be asked to stop cycling and the equipment will monitor how well your heart and lungs recover from exercise. In total the test may take around 45 minutes to complete.
Diagnosis and testing
To determine what kind of treatment is most appropriate for each patient, some testing will be needed to work out how severe the pectus condition is.
Most of the time, surgeons can determine how severe your pectus condition is by testing your heart and lungs, to see if they are impacted by the shape of your chest. It’s also important to speak to patients, to understand how their pectus condition effects their life.
Some surgeons might work out the severity of pectus excavatum using the Haller index. The Haller index is a mathematical way of describing the shape of the sternum, when looking at a CT scan of the thorax. Each patient’s Haller index is worked out by taking measurements of the space inside the chest cavity. Once you’ve worked out the Haller index, it is then applied to the below scale, to work out how severe the pectus excavatum is:
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Less than 2 = a normal chest
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Between 2 and 3.2 = mild excavatum
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Between 3.2 and 3.5 = moderate excavatum
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Above 3.5 = severe excavatum
Please note: whilst the Haller index is a useful way of measuring pectus excavatum, it isn’t always reflective of how the shape of a patient’s sternum is affecting their heart and lung function.
If you go to see a cardiothoracic surgeon or consultant about your pectus condition, these are some of the tests you might have:
CT scan
A CT scan uses X-rays and computer technology to produce an image of the inside of your body.
During a CT scan, the patient lies on a bed that moves through the scanner to generate the images. The radiographer might ask you to take some deep breaths or hold your breath as you pass through the scanner. CT scans take only a few minutes to complete.
A CT scan gives your consultant a good idea of what the space inside your chest looks like. In these example CT scans you can see a patient with pectus excavatum who has had corrective surgery. Before surgery, the patient’s sternum is dented in towards the spine reducing the space for the heart and lungs to function. You can see clearly from the scans that the heart is being pushed to one side by the collapsed sternum.
Cardiopulmonary exercise test (CPET)
Lung function test
Spirometry is the most common type of lung function test. This test measures how air you can breathe in and out of your lungs and how quickly you can exhale. This helps to determine your lung capacity and whether there is any obstruction to the breathing.
During a lung function test, you will have a clip on your nose and a mouthpiece in your mouth to blow into. The mouthpiece is connected to a machine which measures the breaths you take. As part of the test, you’ll be asked to take big breaths into the mouthpiece, expelling all of the air in your lungs as quickly as possible. You’ll be asked to repeat this multiple times to ensure an accurate result.
Echocardiogram
An echocardiogram is an ultrasound of the heart, that shows how the heart is functioning.
During an echocardiogram, the patient lies down on an exam bed whilst a sonographer moves a small probe across their chest. An image of the heart will appear on a screen beside you. The sonographer will take some measurements of the images, which will show how well your heart is functioning. Echocardiograms can take between 5-15 minutes to complete. During the scan, the sonographer might ask you to turn onto your side and take some deep breaths, so they can get the best image possible.
