The routine test used to monitor patients’ breathing is not entirely reliable as it can sometimes be performed incorrectly by healthcare professionals.
- Practiced on patients suffering from respiratory difficulties, this test of about thirty seconds is considered unreliable because it does not take into account the respiratory irregularities of the patients.
Performed on patients suffering from respiratory problems, and in particular those with Covid-19, a routine respiratory test could prove to be unreliable and thus put lives in danger. This is what points out a new study conducted by the University of Edinburgh (Scotland) and published online on ERJ Open Research. According to the researchers, the breathing test is regularly performed over too short a period of time – around 30 seconds – to give a reliable result. However, incorrect results can mean that clinical staff cannot detect how badly a patient with respiratory problems is feeling.
These results are all the more worrying since the test is carried out on people suffering from Covid-19, a disease which can severely affect respiratory capacity.
Too short to be reliable
Widely used, this breath test consists of a count of breaths over a period of 30 seconds. Nevertheless, explain the authors of the study, this short duration does not take into account the respiratory irregularities of the patients. However, this practice could be improved by increasing the duration of the measurement to two minutes.
The test is performed on all patients who arrive at the hospital and have respiratory symptoms, as part of what medical staff call “Early Warning Scores” (EWS), set in place to prevent deterioration of the clinical condition of patients in hospital wards.
Based on the study data, most clinical staff believe that counting the breaths taken over a 30-second period gives a reasonable measure of respiratory rate. However, since breathing is not always regular, there may be a variation in respiratory rate when measured over a short period of time, which skews the results.
Increase measurement time to 2 minutes
The team analyzed respiratory recordings from 25 hospitalized patients to determine the extent of this variation. Each recording was made for 30 minutes to an hour in patients with respiratory, cardiac, neurological and urinary diseases.
The researchers sampled the recordings randomly, multiple times, in the same way that clinical staff can measure breathing rate. They then found that there was a large variation in breathing rate for each patient: more than half of the measurements differed by more than three breaths per minute. “This variation may seem small, but in 40% of cases, an incorrect rate would have meant that the alert scoreboard was wrong”they explain.
For Dr Gordon Drummond, Honorary Clinical Lecturer at the University of Edinburgh, “the lack of precision in the measurement of the respiratory rate could have consequences on the treatment of a patient. We believe accuracy would be improved by increasing the measurement time to two minutes and using specialized equipment to measure respiratory rate..”
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