Many of the snoring and obstructive sleep apnea patients complaints of difficulty to breathe and it is important to rule out any associated COPD or unrelated chest pathology like asthma, chronic bronchitis or restrictive lung diseases. So I do Lung function test or called pulmonary function tests ( PFT) as a preoperative test to determine if the patient is medically able to tolerate sleep disorder surgery. Abnormal PFT can be seen in some obese snoring sleep apnea patients.
About Lung Function Test (Pulmonary Function Test- PFT)-Spirometry
A lung function test is a series of breathing tests where you will be required to breathe in different patterns through a mouthpiece. These patterns may require you to breath fast, take big breaths in, empty your lungs out and hold your breath. The respiratory scientist conducting the test will talk you through each process. A lung function test is a simple, non-invasive way to examine the lungs and your breathing. The PFT measures the patient’s lung capacity and ability to move oxygen into the blood. It is a very important test to evaluate for common lung conditions such as asthma, emphysema or COPD.
The test can be repeated after giving ventolin inhaler to see any difference in the reading.
It will take around 45 to 50 minutes to complete the breathing test.
Before the test tell the patient not to smoke 6 hours before the test if smokers. Do not use inhalers or nebulizer four hours prior to the test.
Chronic obstructive pulmonary disease (COPD) and sleep apnea syndrome (SAS) have been found to coexist in many patients, who are at increased risk of respiratory insufficiency. In a large series of consecutive sleep apnea syndrome patients, an obstructive ventilatory defect defined by a FEV1/VC ratio (forced expiratory volume in one second/vital capacity) below 60% was found in 10% cases, which is probably higher than the prevalence of COPD in the general population. .
Obesity, smoking and asthma secondary to gastro esophageal reflux (GERD) may have contributed to the decrease in expiratory flow rates. An increased frequency of gastro esophageal reflux has been reported in OSA patients.
PFT must be included in the investigation work up of all the OSA patients before considering CPAP or surgical options.