Testing for fever, high pulse rate, crackly breath sounds, and low oxygen levels could be key to helping GPs distinguish pneumonia from less serious infections, according to a large study published in the ERJ.
Researchers studied 28,883 patients who had visited GPs at 5,222 different surgeries across the UK with signs of an infection in the lungs or airways, such as a cough. They collected data on the patients’ symptoms, results of any tests and details of any treatment given, and continued to monitor the patients for the following 30 days.
A total of 720 patients in the study went on to have a chest x-ray and of these, 115 were found to have pneumonia.
The researchers found that some signs and symptoms were more common in patients who turned out to have pneumonia. These were a temperature higher than 37.8°C, a crackling sound in the patient’s lungs, a pulse rate of more than 100 beats per minute, and oxygen saturation in the blood lower than 95%. They found that 86.1% of patients with pneumonia exhibited at least one of these signs.
The study was led by Michael Moore, Professor of Primary Care Research at the University of Southampton, and funded by the National Institute for Health Research. He explained: "This study shows that there are objective measures that indicate whether or not a patient might have pneumonia, and they are all factors that GPs can already test for. Whereas other symptoms like sputum colour do not seem to help.
"This is the first large study to look at whether oxygen saturation might indicate pneumonia and the results do support using pulse oximetry in assessing patients in primary care. We can’t rule out that widespread use might result in more patients being referred to hospital. For this reason, it should be considered by GPs in conjunction with a clinical examination and other factors."
Although the study is large, the researchers caution that its main weakness is that it relied on routine x-rays to confirm the diagnosis of pneumonia. They point out that relatively few people had an x-ray and so milder cases of pneumonia would still have been missed.