Less reliance on ventilators may reduce death rate by 50% in coronavirus patients put on them, says study
The new coronavirus has led to a huge demand for ventilators globally. In the absence of approved drugs or treatments, surviving severe COVID-19 infection crucially depends on supportive care, including breathing support where necessary. This includes ventilators, which are machines that help patients breathe. However, researchers now say that less reliance on ventilators may reduce the current high death rate of more than 50% in “invasively ventilated” COVID-19 patients.
The research team says that in patients with moderate-severe COVID-19, supplemental oxygen can be provided using simple nose prongs or face masks. “Supplemental oxygen is essential for the treatment of severe COVID-19 with hypoxemia (below-normal level of oxygen in the blood), also in resource-poor settings. All hospitals coping with COVID-19 patients have to ensure the availability of supplemental oxygen.
Oxygen sources include oxygen cylinders, oxygen concentrators, and centralized, piped oxygen systems. Oxygen delivery can be increased by using a non-rebreathing mask and prone positioning,” says the team in their findings published in the American Journal of Tropical Medicine and Hygiene. It includes experts from Mahidol University, Bangkok; University of Oxford, UK; and Amsterdam University Medical Centers, Amsterdam, among other institutes.
The researchers say that COVID-19 affects the lungs differently than other causes of acute respiratory distress syndrome or severe pneumonia. “An important difference in COVID-19–affected lungs is the coexistence of severely affected lung areas adjacent to relatively unaffected areas,” says the team. Hence, they emphasize that mechanical ventilation may even be harmful to the lungs of some COVID-19 patients.
Accordingly, the researchers say that low levels of blood in the oxygen in COVID-19 patients should not be used as an immediate excuse to use mechanical ventilation. The trigger for using mechanical ventilation should, within certain limits, probably not be based on hypoxemia alone but more on respiratory distress and fatigue, the team recommends. “The presence of only hypoxemia should in general not trigger intubation (which is when a mechanical ventilator is used) because hypoxemia is often remarkably well-tolerated (among COVID-19 patients).
Patients with fatigue and at risk for exhaustion, because of respiratory distress, will require invasive ventilation. In these patients, lung-protective ventilation is essential,” explain researchers.
Intubation is a procedure that is used when patients are unable to breathe on their own. The doctor puts a tube down your throat and into the windpipe to make it easier to get air into and out of the lungs. The ventilator pumps in air with extra oxygen, and then it helps to breathe out air that is full of carbon dioxide. This is referred to as mechanical ventilation.
The research team also explains that severe pneumonia in COVID-19 differs in some important aspects from other causes of severe pneumonia. “Severe pneumonia in COVID-19 differs in some important aspects from other causes of severe pneumonia or acute respiratory distress syndrome, and limiting the positive end-expiratory pressure level on the ventilator may be important. Invasive ventilation in the prone position should start early and last sufficiently long. This ventilation strategy might reduce the currently very high case fatality rate of more than 50% in invasively ventilated COVID-19 patients,” says the team.
Phil Rosenthal from the University of California, San Francisco, told STAT News, “It’s important to highlight aspects of COVID-19 that differ from other diseases that require respiratory support. Patients with COVID-19 pneumonia are often less breathless compared to other patients with similar (blood oxygen) levels. This difference may allow physicians to avoid intubation/ventilator support in some patients.”
According to the research team, the strategies recommended by them could be critical in many resource-limited settings, where the provision of quality mechanical ventilation is challenging. “This is not only because of the low numbers of ICU beds equipped with mechanical ventilators but also because of issues related to infrastructure, equipment maintenance, human resources, and training,” says the team.
A few studies have also shown that mechanical ventilation may not help. In one study, for example, 30 (81%) of 37 patients requiring mechanical ventilation had died by 28 days. Another recent study, which examined outcomes among 5,700 patients hospitalized with COVID-19 in the New York City area, says that during hospitalization, 373 patients (14.2%) were treated in the intensive care unit care, of which 320 (12.2%) received invasive mechanical ventilation, 81 (3.2%) were treated with kidney replacement therapy, and 553 (21%) died.
The analysis shows death for those requiring mechanical ventilation was 88.1%. “Mortality rates for those who received mechanical ventilation in the 18-to-65 and older-than-65 age groups were 76.4% and 97.2%, respectively. Mortality rates for those in the 18-to-65 and older-than-65 age groups who did not receive mechanical ventilation were 19.8% and 26.6%, respectively,” says the study published in JAMA.