In This Article
- Hypoxemia is often a presenting sign of inpatients with COVID-19, and it can progress rapidly
- To protect patients from injurious breathing patterns, physicians should consider early intubation
- Intubation should be performed by the most experienced physician available, to limit the number of attempts and therefore reduce the risk of exposure to the virus
- The ventilator weaning process for patients with COVID-19 should be gradual; clinicians should not make large changes every day
Even physicians who don't specialize in critical care may be called on to manage respiratory distress in patients with COVID-19. Ari Moskowitz, MD, associate director of the Medical ICU at Beth Israel Deaconess Medical Center, reviewed principles of this care—and what's being discovered that's particular to COVID-19—during Massachusetts General Hospital's virtual medical grand rounds on March 26, 2020. The meeting was a joint presentation of Mass General, Beth Israel and Brigham and Women's Hospital.
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The Case Against Conventional Management of Hypoxia
Hypoxemia is often a presenting sign of COVID-19 and can progress rapidly.
Noninvasive positive-pressure ventilation aerosolizes respiratory droplets and increases the risk of transmitting SARS-CoV-2. In a case series from China, it had a very high failure rate, so it exposed health care workers without much benefit in preventing intubation.
In addition, a patient on noninvasive ventilation has a very high respiratory drive, taking large breaths at a rapid rate with large pleural pressure swings. This can actually worsen lung injury and propagate acute respiratory distress syndrome (ARDS).
High-flow nasal cannulas did not increase transmission of SARS-CoV, a very similar predecessor coronavirus, to health care workers during the SARS epidemic of 2002–2003. Even so, Beth Israel and many other centers are avoiding it or capping it at less than the typical flow rate of 60 L/min.
Accomplishing Early Intubation
Early intubation takes control of the patient's breathing, protecting them from injurious breathing patterns.
Specific recommendations are to:
- Have intubation performed by the most experienced physician available, to limit the number of attempts and therefore reduce the risk of exposure to the virus
- Think through the supplies needed and gather them before going into the patient's room
- Consider video laryngoscopy, which lets the physician stand a bit away from the patient
- Limit the number of health care workers in the room
- Limit bag valve masking if possible, using rapid sequence techniques; if a bag valve mask is used, put a viral filter on it
- Be prepared for profound desaturation right after intubation because of derecruitment
The Need for Patience
The trend in critical care has been lighter sedation and trying to get people off ventilators as quickly as feasible. In contrast, patients with COVID-19 need a much more gradual weaning process. Some patients, even children and young adults, require two to three weeks on the ventilator. Clinicians should not make large changes every day.
Adjunctive Management of ARDS
Prone positioning has a number of benefits, including avoidance of ventilator perfusion mismatching, better recruitment by shifting the mediastinum off the chest, improved secretion management and more homogeneous distribution of stress on the lungs. A number of case series have reported substantial improvement in COVID-19 patients with prone positioning if done for at least 16 hours a day. At Beth Israel, a team goes from patient to patient to "prone and de-prone" them every day.
Inhaled nitric oxide has been shown to improve oxygenation in ARDS, and it may have antiviral effects. However, it's a limited resource and very expensive.
Neuromuscular blockade can be useful in preventing ventilator dyssynchrony. Paralytics are not recommended as a matter of protocol, but if unable to achieve synchrony with sedation, they are something to consider. Some patients with COVID-19 require a longer than usual duration of paralytics.
Extracorporeal membrane oxygenation requires a high investment of time and personal protective equipment, but there have been a few reports of effectiveness in patients with COVID-19. It's typically done venovenously to support the lungs.
Shock (septic, cardiogenic or a combination) is uncommon in COVID-19. The most consideration is to be conservative with fluids. Patients with COVID-19 die because of hypoxemia, so physicians should turn early to a vasopressor. The first-line choice is norepinephrine. Based on weak evidence, the Society for Critical Care Medicine recommends empiric use of antibiotics; Beth Israel uses them for the first 24 to 48 hours until cultures come back.
Cardiomyopathy and arrhythmias have been reported in a small minority of COVID-19 patients, sometimes as a late finding even after ARDS is improving. It's not clear whether these complications occur because of viral myocarditis, stress or cytokine storm—they may reflect a combination of those phenomena. Treatment depends on determining the cause as best one can.
The grand rounds session also included a presentation by Rebecca M. Baron, MD, and Jason Griffith, MD, PhD, about the pathogenesis of COVID-19 and a presentation by Robert Hallowell, MD, about potential therapies.
Massachusetts General Hospital has made its guidance for treating COVID-19 outpatients and inpatients publicly available. All documents are subject to revision.
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