BENGALURU: There is reduced mortality among those severely ill Covid-19 patients who are subjected to prone ventilation (made to lie on their stomachs while on ventilators to ease breathing), but they face the risk of damaged nerves and permanent disabilities post recovery, a new study has revealed.
The study has been accepted by the British Journal of Anaesthesia. Researchers from Northwestern University’s School of Medicine and Shirley Ryan AbilityLab, both in Illinois, USA, found that the nerve damage is the result of reduced blood flow — due to blood coagulation, a common feature in Covid-19 patients — and inflammation.
They also found that such nerve damage did not occur among non-Covid-19 patients subjected to prone ventilation. The most common injuries are wrist and foot drops, loss of hand functions and frozen shoulder, caused by distinct damage in the ulnar and radial nerves in the elbow, sciatic nerve linking the spine with the legs, and the common fibular nerve in the back of the knee. The study found some patients needed assistance, like a wheelchair, brace or cane.
Proned patients not scanned in K’taka
The study’s lead investigator, Dr Colin Franz, a physician-scientist at Shirley Ryan AbilityLab and assistant professor of physical medicine and rehabilitation and neurology at Northwestern’s Feinberg School of Medicine, and his colleagues have been conducting therapeutic nerve stimulation to regenerate nerves.
But they found that the damaged nerves are less likely to regrow in patients with pre-existing conditions. “This could mean permanent difficulties with walking or critical hand functions like writing, using a computer or mobile,” Dr Franz says.
Up to 15 per cent of most severely ill Covid-19 patients surveyed had permanent nerve damage. The researchers estimate that worldwide, thousands may be impacted by this. However, such studies have so far not been conducted in India. In Karnataka, about 800 severely sick Covid patients have been subjected to proning, of which about 500 have recovered, but not scanned for nerve damage.
Dr K Sudheesh, anaesthetist at the Bangalore Medical College Research Institute, who is treating critical Covid patients at Victoria Hospital, said, “Patients do complain about neck and shoulder pains post prone ventilation. But so far, we haven’t seen any worse side effects. We do not even force the patients, and we allow only those who can stay in the position for long. We even give them lateral position, as it will relieve the stress on their joints.” However, Dr Franz points out that the injuries are missed because critically ill patients are expected to wake up with some generalised, symmetric weakness because they have been bedridden.
It was the pattern of weakness in Covid-19 patients that caught the researchers’ attention during rehabilitation since quite often, an important joint such as the wrist, ankle or shoulder, would be completely paralysed on one side of the body.
Dr Anoop Amarnath, head of the Scientific Board and Chairman, Geriatric Medicine, Manipal Hospital, and member of the state Critical Care Support Team (CCST), says, “There are protocols to be followed for prone ventilation. Prone ventilation is performed on patients in Dakshina Kannada district and in some centres of Bengaluru too. Usually, patients are sedated, so they won’t complain of pain. Post viral myalgia (post viral infections), they will have side-effects like body ache, but it might not be due to proning. Any centre following proning, should follow specialised guidelines for safety of patients.”