This method identified the sickest coronavirus patients best
Emergency rooms use different ways to determine which coronavirus patients will need intensive care the most. One method more accurately predicted which patients would be hardest hit, according to a new study.
When patients are admitted to hospital with an acute illness, doctors measure symptoms such as respiration rate, blood pressure, heart rate and body temperature, and they look for signs of acute confusion.
This helps them differentiate the sickest patients from the less sick, and determine who needs intensive care.
«We didn’t know much about COVID-19 in the beginning, or what symptoms were most important. When the first COVID-19 patients were admitted, we were quick to start a study», says Marius Myrstad, chief physician and a researcher at Bærum Hospital in Norway.
The doctors wanted to find out which symptoms could best predict which patients would go on to develop a serious course of the disease and thus would have the greatest need for acute intensive care, according to Myrstad, who is a specialist in internal medicine and geriatrics.
Myrstad and his colleagues used different methods to determine the prognosis of COVID-19-pations, and found substantial differences in the accuracy of these methods.
Crucial to saving lives
The methods used in the emergency room can, in the worst case, be a matter of life or death.
«In a situation where doctors are under pressure with a large influx of patients and limited capacity, the use of the most suitable method could be crucial in saving as many lives as possible», Myrstad says.
The study at Bærum Hospital is the first to compare different emergency medical scoring tools, and how well they predict the risk of a serious course of COVID-19.
The study was published in the Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine in July.
Didn’t know what was typical of COVID-19
Bærum Hospital tested patients using several methods simultaneously when they were first examined in the emergency room. This enabled them in retrospect to see which method best predicted which patients would be hardest hit.
These methods are called scoring tools, and emphasize different symptoms and conditions.
«Although all the scoring tools we use in the emergency department are well tested and have proven useful in patients with other infections, we didn’t know how suitable they were for patients with COVID-19», Myrstad says.
Twenty per cent died
The study followed 66 patients who were admitted to Bærum Hospital with COVID-19 disease from March 9 to April 27.
The patients ranged in age from 30 to 95, with a median age of 71.5. Fifty-eight per cent were men. High blood pressure and heart disease were the most common chronic conditions.
Of these, 15 patients, or 23 per cent, developed a severe course of the disease. A high respiratory rate, poor blood oxygen saturation and confusion were common at admission.
Thirteen patients died while hospitalized, or 20 per cent.
Fifty-three were discharged alive
Of the 66 patients admitted and included in the study, 53 survived.
Patients who were still hospitalized when the study was terminated were excluded from the study, as well as two patients who were diagnosed with a positive COVID-19 test, but who were hospitalized for other reasons.
The doctors diagnosed all patients using two methods. Both scoring tools are widely used to identify serious disease outcomes in patients with infections.
Once they knew the outcomes, they looked back at how accurate their diagnoses had been at admission. One method proved to be more sensitive in predicting which patients would have a very serious course of COVID-19.
«The NEWS2 method excelled. It captured as many as 87 per cent of the patients who developed very serious illness, in that they received a high score at admission», Myrstad says.
NEWS2 stands for The National Early Warning Score 2. A high score was considered to be above 5 or 6. These patients became so ill that they had to be admitted to intensive care.
The second method which is widely used, qSOFA, only captured 27 per cent of the patients who had a severe course. qSOFA stands for The Quick Sequential Organ Failure Assessment.
The NEWS2 method thus proved to be better at determining which patients were most likely to be severely affected by COVID-19.
How the methods differ
Both standardized methods are widely used. The qSOFA method is typically used in suspected infectious illnesses such as sepsis.
The qSOFA method: The alarm bells go off if the patient has at least two of these criteria: high respiratory rate (an abnormally high number of breaths per minute), low blood pressure or acute confusion / altered consciousness.
NEWS2 method: Scores for high respiratory rate, blood pressure, heart rate, unconsciousness or confusion, low or high body temperature, low oxygen saturation, and possible need for supplemental oxygen.
Rapid breathing, low oxygen saturation
The reason why the NEWS2 method seems to be more suitable for diagnosing a serious course of COVID-19 is probably because the disease primarily affects the lungs.
It also seems that the heart rate and blood pressure of patients with COVID-19 is less affected than in than other seriously ill patients with infections such as sepsis.
«What particularly distinguishes the methods is that the NEWS2 method also puts a priority on low blood oxygen saturation, called hypoxemia», Myrstad says.
«This method also assigns additional points when patients need a supplemental oxygen supply and have an abnormally high or low body temperature», he says.
Although this is a small study, Myrstad points out that it is representative of the patients at Bærum Hospital at the beginning of the epidemic.
Means an abnormally low amount of oxygen in the blood. This is easily measured by pulse oximetry in all hospital patients. Hypoxia means a lack of oxygen in one or more organs. The most common symptoms of hypoxemia are in the respiratory tract — especially shortness of breath or difficulty breathing. With pronounced hypoxia, a person’s skin can turn blue, but this is not typically the first symptom. Some COVID-19 patients have "silent hypoxia", which means a lack of oxygen with few or no symptoms.
Can predict who needs help first
In a normal situation with good capacity, the focus is on providing the best treatment possible for all patients who come in.
«We have managed that so far, and we have not had to prioritize anyone, because we have had good capacity», Myrstad says.
In a stressful situation, with great demand and limited resources in the hospital, the best method will be useful in identifying the patients who have the greatest need for urgent help.
«That’s why it’s important to know which symptoms we should emphasize, so we can identify which COVID-19 patients should be first priority», Myrstad says.
Many arrived late
Patients came to Bærum Hospital for treatment later than they should have.
«Not only COVID-19-patiens came late, but also other patients, such as people who have had a stroke and who waited too long at home before going for medical care because they didn’t want to burden the health care system», he says.
What do Norwegian hospitals use?
The Norwegian Directorate of Health says that it is largely up to the hospitals and professionals to decide which risk identification tools and diagnostic tools to use, although they must follow general requirements regulated by law.
At Haukeland University Hospital i Bergen they used a different method than in Bærum. All patients, including those with COVID-19, are assessed according to SATS - South African triage scale, writes Rune Bjørneklett at Haukeland in an email to sciencenorway.no.
This method is similar to NEWS, the national early warning score, but also assesses whether the patient has an injury and whether the patient can walk by himself or herself.
Translated by Nancy Bazilchuk
M. Myrstad et al.: National Early Warning Score 2 (NEWS2) on admission predicts severe disease and inhospital mortality from Covid-19 – a prospective cohort study. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 13 July 2020. https://doi.org/10.1186/s13049-020-00764-3