Prolonged unconsciousness is common in COVID-19 patients, recovery often takes days or even weeks
Prolonged unconsciousness is common in COVID-19 patients, recovery often takes days or even weeks

Prolonged unconsciousness is common in COVID-19 patients, recovery often takes days or even weeks

During the first wave of the COVID-19 pandemic, many patients in intensive care units did not regain consciousness after their breathing tubes were removed and their sedation stopped, leaving clinicians and families with difficult decisions about whether to continue life-sustaining therapy. It is noteworthy that the majority of these patients eventually regained consciousness, but often after days or even weeks. To help provide accurate prognostic information going forward, a team at Massachusetts General Hospital (MGH), New York-Presbyterian / Columbia University Irving Medical Center, Weill Cornell Medicine and New York-Presbyterian / Weill Cornell Medical Center launched a multicenter study to better understand the healing timeline and the reasons for delayed recovery of consciousness in patients with severe COVID-19.

The study, published in Annals of Neurology, involved a retrospective analysis of 795 patients with severe COVID-19 who were treated with mechanical ventilators in the intensive care units of the investigators’ medical centers for at least six days. After respiratory support was completed, clinicians performed daily assessments to see if patients could respond purposefully to a verbal command, a standard measure of consciousness.

Of the 795 patients, 72% survived and eventually regained consciousness before discharge from the hospital. For those who survived, 25% regained consciousness 10 or more days after the ventilator support was stopped, and 10% took more than three weeks to recover.

When we investigated the potential causes of delayed recovery of consciousness, we found that low oxygen levels in the blood correlated with the time to recovery, even after taking into account other factors such as exposure to sedatives. This relationship was dose-dependent – the more episodes of low blood oxygen a patient experienced, the longer it took them to wake up. “

Brian L. Edlow, MD, co-senior author, associate director of the Center for Neurotechnology and Neurorecovery at MGH and associate professor of neurology at Harvard Medical School

Most patients had normal brain scans, suggesting that the prolonged time to regain consciousness was not related to stroke, swelling, or bleeding in the brain. “These observations were consistent across all three medical centers and during the first and second increases in the COVID-19 pandemic,” said Jan Claassen, MD, co-chair of the study and associate professor of neurology at Columbia University Vagelos College of Surgeons and Physicians. .

Further research is needed to understand the mechanisms behind the link between low blood oxygen levels and longer time to regain consciousness. “We have seen similar phenomena in rare patients with cardiac arrest who were treated with hypothermia,” said Nicholas D. Schiff, MD, co-leader of the study and Jerold B. Katz professor of neurology and neuroscience at the Brain and Mind Research Institute. and co-director of Consortium for Advanced Study of Brain Injury (CASBI) at Weill Cornell Medicine and a treating neurologist at the New York-Presbyterian / Weill Cornell Medical Center. “Hypothermia seems to protect cardiac arrest patients from neurological damage in ways we still do not understand. We are now moving forward with studies aimed at uncovering common underlying mechanisms of neuroprotection that may connect these two groups of patients.”

Regardless of the underlying mechanisms that have not yet been revealed, the results of the study may have an immediate clinical effect. “These results provide us with more accurate information to guide families who are deciding whether to continue life-sustaining therapy in unconscious COVID-19 patients,” says Edlow. “The fact that delayed recovery of consciousness was consistently seen at three different medical centers, across two elevations of COVID-19, suggests that we should consider the possibility of delayed healing when making death decisions for these patients on intensive. unit. “

The results can also be applied to critically ill patients with other medical conditions. “We are trying to determine if the experience of patients with severe COVID-19 can inform our approach to oxygen targeting and sedation management in the intensive care unit for the broad spectrum of patients in need of mechanical ventilation,” says co-author Emery N. Brown, MD, ph .d., professor of anesthesia at Harvard Medical School, anaesthesiologist at MGH and professor of medical engineering and computational neuroscience at the Massachusetts Institute of Technology.

Co-author Megan E. Barra, PharmD, a Clinical Pharmacist in Neurocritical Treatment for MGH, notes that further research is also needed to determine the degree of functional improvement in patients with COVID-19 or other conditions that experience long-term unconsciousness. after respirator. support is stopped. “We did not look at long-term restoration of cognition or functional independence in our study, but this is an important consideration for patients and their families,” she says.


Journal reference:

Waldrop, G., et al. (2022) Prolonged unconsciousness is common with COVID-19 and is associated with hypoxemia. Annals of Neurology.

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