Doctors and researchers are concerned about the increase in blood clotting among COVID-19 patients. Dr. Jeffrey Laurence, a hematologist at Weill Cornell Medicine in New York City wrote in an email to CNN that the number of clotting problems on COVID-19 patients in the ICU is unprecedented. It appears to be widespread in severe coronavirus patients.

Blood clotting is another dangerous complication of COVID-19 that has been a rising concern in frontline reports from the United States, Europe, and China. In Washington, Broadway and TV actor Nick Cordero's doctors have no choice but to amputate his right leg after spending nearly three weeks in the intensive care unit being treated for COVID-19. His blood flow has been obstructed by a clot.

Shari Brosnahan, a critical care doctor at NYU Langone said that 40-year-olds patients in the ICU have clots in their fingers that look like they will lose a finger because of the virus. One of her patients is suffering from a lack of blood flow to both feet and both hands that an amputation is necessary or the blood vessels may get so damaged that the limbs might drop off by themselves.

These so-called "thrombotic events" are backed up with research from the Netherlands who recently published their paper in the journal Thrombosis Research and found that 31% of 184 patients suffered from thrombotic complications are remarkably high.

Blood clots can cause amputation on limbs and also lethal pulmonary embolisms, heart attacks, and strokes once it reaches the lungs, heart and the brain.

Why does blood clotting happens?

An international team of experts led by Dr. Behnood Bikdeli from the New York-Presbyterian Hospital studied the issue of blood clotting among COVID-19 patients and published their findings in the journal of The American College of Cardiology.

Bikdeli said that their findings showed that the risks among COVID-19 patients were so great that they "may need to receive blood thinners, preventively, prophylactically, even before imaging tests are ordered."

The reasons why blood clotting occurs are not fully understood, but Bikdeli offered several possible explanations.

Patients with severe cases of COVID-19 are more likely to experience blood clotting when they have underlying medical conditions such as heart or lung disease. Another explanation, is that patients in the intensive care units are likelier to develop a clot because they are staying still for long periods.

Some research is also indicating that "cytokine storm"-an abnormal immune reaction- are linked to higher rates of clotting as it is widely associated with COVID-19.

But there could also be something in the virus itself causing the clotting. A paper in The Lancet journal last week showed that the virus can infect the endothelium cells of blood vessels that could interfere with the clotting process.

Too many micro clots

Although Heparin is effective in some patients, some clots are too small that they do not work for all patients, according to Brosnahan. Autopsies have shown that there are hundreds of micro clots in some people's lungs.

Military veterans hospital intensive care doctor, Cecilia Mirant-Borde said that micro clots help explain why ventilators work poorly for patients with low blood oxygen. It is the micro clotting that is blocking the circulation which leads the blood leaving the lungs with lesser oxygen than it should get.

Researchers are learning more every day since the pandemic began five months ago in Wuhan, China. Brosnahan said that it is possible that the cause of the damages are all the same thing, and that there will be the same solution for it.