, and a bedside risk management strategy based on modifiable risk factors can help prevent lingering effects on cognition, according to an article published in Critical Care.
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Several factors can contribute to an increased risk of ICU delirium in COVID-19 patients, wrote Katarzyna Kotfis, MD, of Pomeranian Medical University, Szczecin, Poland, and colleagues.
“In patients with COVID-19, delirium may be a manifestation of direct central nervous system invasion, induction of CNS inflammatory mediators, a secondary effect of other organ system failure, an effect of sedative strategies, prolonged mechanical ventilation time, or environmental factors, including social isolation,” they said.
Delirium in the context of COVID-19 can mean an early sign of infection, so patients should be screened using dedicated psychometric tools, the researchers wrote. Also, COVID-19 has been shown to cause pneumonia in elderly patients, who are at high risk for severe pulmonary disease related to COVID-19 and for ICU delirium generally, they said.
In addition, don’t underestimate the impact of social isolation created by quarantines, the researchers said.
“What is needed now, is not only high-quality ICU care, concentrated on providing adequate respiratory support to critically ill patients, but an identification of the source and degree of mental and spiritual suffering of patients as well as their families to provide the most ethical and person-centered care during this humanitarian crisis,” they emphasized. However, they acknowledged that nonpharmacologic interventions such as mobility outside the ICU room and interactions with family members are limited by the COVID-19 situation.
The researchers noted several mechanisms by which the COVID-19 virus may cause brain damage, including through the dysfunction of the renin-angiotensin system.
“Inflammatory response of the CNS to viral infection seems to be another important reason for poor neurological outcome and occurrence of delirium,” in COVID-19 patients, they said.
As for risk-reduction strategies, the researchers noted that “delirium in mechanically ventilated patients can be reduced dramatically to 50% using a culture of lighter sedation and mobilization via the implementation of the safety bundle called the ABCDEFs promoted by the Society of Critical Care Medicine in their ICU Liberation Collaborative,” although COVID-19 isolation is a barrier, they said.
The ABCDEF bundle consists of Assessment of pain, Both spontaneous awakening trials and spontaneous breathing trials, Choice of sedation, Delirium (hyperactive or hypoactive), Early mobility, and Family presence; all of which are challenging in the COVID-19 environment, the researchers said.
They advised implementing easy screening methods for delirium to reduce the burden on medical staff, and emphasized the importance of regular patient orientation, despite social separation from family and caregivers.
“No drugs can be recommended for the prevention or treatment of ICU delirium other than avoidance of overuse of potent psychoactive agents like sedatives and neuromuscular blockers (NMB) unless patients absolutely require such management,” they added.
Dr. Mangala Narasimhan
“Delirium is so common and so hard to manage in the COVID-19 population,” Mangala Narasimhan, DO, of Northwell Health in New Hyde Park, N.Y., said in an interview. Delirium is impacted by many sources including a viral encephalopathy, the amount and duration of sedation medications, and prolonged intubation and hypoxemia, she said. “Managing the delirium allows you to wake the patient up successfully and without a lot of discoordination. This will help with weaning,” she noted. Barriers to delirium management for COVID-19 patients include the length of time on a ventilator, as well as amount of sedatives and paralytics, and the added issues of renal insufficiency, she noted. “How they can be addressed is thoughtful plans on the addition of long-term sedation for withdrawal symptoms, and anxiolytics for the profound anxiety associated with arousal from this type of sedation on ventilators, she said. The take-home message for clinicians is the need to perform weaning trials to manage delirium in the ICU. “We have to combat this delirium in order to be successful in taking these patients off of ventilators,” she said. Dr. Narasimhan added that more research is needed on areas including drug-to-drug interactions, duration of efficacy of various drugs, and how the virus affects the brain.
Dr. David L. Bowton
“Adherence to the ABCDEF bundle can reduce the incidence of delirium, from approximately 75% of mechanically ventilated patients to 50% or less,” David L. Bowton, MD, of Wake Forest Baptist Health in Winston-Salem, N.C., said in an interview.
“Importantly, in most studies, bundle adherence reduces mortality and ICU length of stay and lowers the total cost of care. However, isolation of patients and protection of staff, visitor restrictions, and potentially stressed staffing will likely alter how most institutions approach bundle compliance,” he said. “Gathering input from infection control clinicians and bedside providers from multiple disciplines that consider these factors to critically examine current bundle procedures and workflow will be essential to the creation and/or revision of bundle processes of care that maintain the integrity of the ABCDEF bundle yet preserve staff, patient, and family safety,” he said.
“We did not have strong evidence to suggest an optimal approach to treating delirium before the advent of the COVID-19 pandemic, so I do not believe we know what the best approach is in the current environment,” Dr. Bowton added. “Further, vigilance will be necessary to ensure that altered consciousness or cognition is ICU delirium and not attributable to another cause such as drug withdrawal, drug adverse effect, or primary central nervous system infection or immune response that mandates specific therapy,” he emphasized.
For clinicians, “this study reminds us of the importance of the ABCDEF bundle to improve outcomes of critical illness,” said Dr. Bowton. “It highlights the difficulties of providing frequent reassessment of pain, comfort, reassurance, and reorientation to critically ill patients. To me, it underscores the importance of each institution critically examining staffing needs and staffing roles to mitigate these difficulties and to explore novel methods of maintaining staff-patient and family-patient interactions to enhance compliance with all elements of the ABCDEF bundle while maintaining the safety of staff and families.”
Dr. Bowton added, “When necessary, explicit modifications to existing ABCDEF bundles should be developed and disseminated to provide realistic, readily understood guidance to achieve the best possible compliance with each bundle element. One potentially underrecognized issue will be the large, hopefully temporary, number of people requiring post–critical illness rehabilitation and mental health services,” he said. “In many regions these services are already underfunded and ill-equipped to handle an increased demand for these services,” he noted.
Additional research is needed in many areas, said Dr. Bowton. “While compliance with the ABCDEF bundle decreases the incidence and duration of delirium, decreases ICU length of stay, decreases duration of mechanical ventilation, and improves mortality, many questions remain. Individual elements of the bundle have been inconsistently associated with improved outcomes,” he said. “What is the relative importance of specific elements and what are the mechanisms by which they improve outcomes?” he asked. “We still do not know how to best achieve physical/functional recovery following critical illness, which, in light of these authors’ studies relating persisting physical debility to depression (Lancet Respir Med. 2014; 2[5]:369-79), may be a key component to improving long-term outcomes,” he said.
The study received no specific funding, although several coauthors disclosed grants from agencies including the National Center for Advancing Translational Sciences, National Institute of General Medical Sciences, National Heart, Lung, and Blood Institute, and National Institute on Aging. Dr. Narasimhan and Dr. Bowton had no financial conflicts to disclose.
SOURCE: Kotfis K et al. Critical Care. 2020 Apr 28. doi: 10.1186/s13054-020-02882-x.