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A 61-year-old man was hospitalized with COVID-19 for an extended period. During his hospital stay, he was intubated and placed in the prone position, and later developed new onset, left upper extremity weakness and a decreased range of motion. After a neurological examination, there was clinical suspicion that he had sustained brachial plexus damage as a complication of his prone position.
Damage to peripheral nerves is a rare complication of proning typically, but new research out of Northwestern University Feinberg School of Medicine has found an “alarmingly high prevalence” in some COVID-19 patients with acute respiratory distress syndrome (ARDS) who have been proned while on a ventilator.
Now, they are urging physicians to be aware of this possibility and to consider refining their hospitals’ current prone positioning protocols to help reduce the risk.
Compression of the Brachial Plexus During Proning
The study is one of the largest of its kind to examine acquired peripheral nerve injury associated with prone positioning for the management of ARDS, and is one of the first, to the researchers’ knowledge, that is specific to COVID-19.
Published in the British Journal of Anesthesia, Malik et al’s study examined 83 patients from six different tertiary facilities that had been admitted to the Northwestern University Feinberg School of Medicine after hospitalization for COVID-19-related ARDS.
Of these patients, 12 were diagnosed with peripheral nerve injury, 11 of which had undergone prone positioning in acute care in accordance with guidelines set forth by the Intensive Care Society and Society of Critical Care Medicine. There were 21 focal peripheral nerve injury sites with the majority associated with the patients’:
- Ulnar nerve
- Radial nerve
- Sciatic nerve
- Median nerve
Given that prone positioning-related peripheral nerve injuries have rarely been reported in ARDS cases, researchers believe that the “alarmingly high” prevalence of damage to peripheral nerves in their patient cohort (14.5%) must be the result of one or more COVID-19-related factors, including:
- Diabetes, obesity, and old age
- COVID-related muscle injury and virus-induced state of hyperinflammation and coagulability, which can increase the vulnerability of peripheral nerves
Researchers urge physicians to utilize caution when proning, making sure to protect the elbow, upper arm and shoulder to help minimize damage to peripheral nerves. They also recommend that physicians reduce the mechanical load on peripheral nerves, avoiding positions of prolonged focal compression or stretching of nerves.
Proning as a Therapeutic Approach
Introduced in the 1970s, prone positioning was created as a method to help improve gas exchange rates in ARDS patients. Bryan, 1974 noted that in a paralyzed, ventilated patient, the diaphragm is positioned in such a way that that dependent portion of the lung cannot expand fully.
The customary use of positive end-expiratory pressure, he argued, is ineffective in these cases because it caused the lung to expand in nondependent portions. He became one of the first to offer proning as an alternative option, suggesting that the prone position could be “the only feasible means of expanding dependent portions of the lung.”
A later study by Piehl & Brown, 1976 was able to confirm this theory. They were one of the first to demonstrate that changing ventilated patients’ positioning can help improve PaO2 levels; switching patients from supine to prone was able to increase these levels by roughly 47 torr.
Despite these findings, the greatest push towards proning did not come until decades later. In 2013, the landmark Proning Severe ARDS Patients (PROSEVA) study showed that the use of the prone-positioning in ARDS patients significantly reduced 28- and 90-day mortality rates. The results of this study later helped proning become accepted into the standard of care for ARDS patients.
Positioning-related peripheral nerve injury typically results in neuropraxia or axonotmesis. While such damage to peripheral nerves is typically held as an uncommon complication of patient positioning, there hasn’t been much research with proning related to ARDS until this study.
“… peripheral nerve injury after prone positioning for management of severe COVID-19-related ARDS patients is surprisingly common,” the study authors conclude in the British journal of Anaesthesia. “Physicians must be aware of an increased susceptibility to peripheral nerve injury in severe COVID-19 and refine standard protocols in order to reduce the risk.”