Severely ill Covid-19 patients on ventilators are placed in a prone (face down) position because it's easier for them to breathe and reduces mortality. However, a new study shows that life-saving position can also cause permanent nerve damage in these vulnerable patients.
According to the study, published in the British Journal of Anaesthesia, nerve damage is the result of reduced blood flow and inflammation. Other non-Covid-19 patients on ventilators in this position rarely experience any nerve damage.
"This is a much higher percentage of patients with nerve damage than we've ever seen in any other critically ill population," said study author Colin Franz from Northwestern University in the US.
"Ordinarily, very sick people can tolerate the position that helps their breathing. But Covid patients' nerves can't tolerate the forces other people can generally bear," Franz added.
Based on this study, 12 to 15 per cent of the most severely ill Covid-19 patients have permanent nerve damage. Based on the number of Covid patients worldwide, Franz estimated thousands of patients have been impacted.
"The injury has been missed because people who have been critically ill are expected to wake up with some generalized, symmetric weakness because they have been bedridden, Franz said.
The pattern of weakness in the Covid-19 patients caught the researchers' attention during rehabilitation since quite often an important joint such as the wrist, ankle or shoulder would be completely paralyzed on one side of the body.
"We noticed patients are getting a lot of pressure at the elbow or at the neck, so we've made some adjustments to the way we position the joints as well as putting extra padding under the elbow and the knee where there is the most pressure," Franz said.
The most common injuries are wrist drops, foot drops, loss of hand function and frozen shoulder. Some patients had as many as four distinct nerve injury sites. Some people who are dragging a foot need assistance with walking such as a wheelchair, brace or cane.
"This could mean permanent difficulties with walking or critical hand functions like writing or operating a computer or cell phone," Franz said.