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A doctor checking comatose COVID-19 patients for signs of a stroke instead stumbled onto a new clue about how the virus may harm the lungs — thanks to a test that used tiny air bubbles and a robot.<\/p>\n

Dr. Alexandra Reynolds, a neurologist at New York\u2019s Mount Sinai Health System, initially was baffled as she tracked \u201cthe cacophony of sound\u201d made by those harmless bubbles passing through the bloodstream of patient after patient.<\/p>\n

Yet the weird finding excited lung specialists who now are studying if it helps explain why often, the sickest coronavirus patients don\u2019t get enough oxygen despite being on ventilators.<\/p>\n

The tale illustrates how months into the pandemic, scientists still are struggling to unravel the myriad ways the coronavirus attacks — and finding hints in surprising places.<\/p>\n

As patients flooded New York hospitals last spring, Mount Sinai\u2019s intensive care unit that usually handles patients with brain diseases turned overnight into a COVID-19 ward, with patients heavily sedated as ventilators kept them alive.<\/p>\n

\u201cWhen we wake them up, will we notice they have some horrible brain injury?\u201d worried Reynolds, who at first had little way to monitor brain function except to check patients\u2019 pupils. <\/p>\n

A bedside test called a transcranial Doppler uses sound waves to track blood flow in the brain, but it was too risky for health workers to stand by patients\u2019 heads for long periods. <\/p>\n

So Reynolds turned to a new robotic version, a headset that once positioned over the patient can automatically do the tracking. She used it to perform what\u2019s called a bubble study, a commonly used, painless test for stroke risk that involves injecting saline containing tiny air bubbles into a vein. As the microbubbles circulate, the smallest blood vessels in healthy lungs \u2014 called capillaries \u2014 will trap and filter them out of the bloodstream. <\/p>\n

Over several nights in the ICU, Reynolds tested some of her sickest coronavirus patients \u2014 and repeatedly, NovaSignal\u2019s robotic Doppler kept measuring bubbles that, instead of being filtered away, were somehow reaching their brains.<\/p>\n

\u201cThis was really bizarre,\u201d Reynolds said. Often bubbles avoid lung filtering by slipping through a heart defect that\u2019s a well-known stroke risk, but \u201cthere\u2019s no way everyone suddenly has a hole in their heart.\u201d<\/p>\n

But to Mount Sinai lung expert Dr. Hooman Poor, the bubble mystery might be \u201cessentially the missing link\u201d in why these patients weren\u2019t getting enough oxygen: Maybe abnormally dilated lung capillaries, not a heart problem, were letting the bubbles sneak through.<\/p>\n

Poor and Reynolds did more tests. By the end of the pilot study, 15 of 18 tested patients had microbubbles detected in the brain. And backing Poor\u2019s theory, patients with the most bubbles also had the lowest oxygen levels, researchers reported earlier this month in the American Journal of Respiratory and Critical Care Medicine<\/a>.<\/p>\n

Why would capillaries matter?<\/p>\n

Coronavirus patients on ventilators have what\u2019s called ARDS or acute respiratory distress syndrome, an inflammatory lung failure that when caused by other infections blocks oxygen by stiffening lungs. But the coronavirus doesn\u2019t similarly stiffen lungs, Poor explained.<\/p>\n

His new theory: Doctors know the coronavirus attacks the lining of blood vessels, causing dangerous clots. The bubble study suggests maybe blood is being detoured from clogged vessels to unusually widened ones \u2014 and thus flowing through too fast to properly absorb oxygen.<\/p>\n

A rare disorder called hepatopulmonary syndrome causes the same abnormality, and it\u2019s diagnosed with a bubble study.<\/p>\n

The findings are preliminary, not proof that dilated blood vessels are a problem. Still, some autopsies have linked COVID-19 to deformed lung capillaries.<\/p>\n

Next up is a larger study that aims to see if measuring bubbles could help doctors monitor whether patients are improving or worsening.<\/p>\n

The report \u201cI think is really going to generate a lot of talk\u201d among lung specialists, because it\u2019s \u201cmore evidence that the blood vessel is really where the action is,\u201d said Dr. Corey Kershaw of the University of Texas Southwestern Medical Center, who wasn\u2019t involved in the pilot study. <\/p>\n

He cautioned that researchers need to definitively prove a heart defect isn\u2019t playing a role.<\/p>\n

But, \u201cit\u2019s an example of, there are so many things we still don\u2019t know,\u201d Kershaw added, praising the creativity used to find this latest clue.<\/p>\n

___<\/p>\n

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute\u2019s Department of Science Education. The AP is solely responsible for all content.<\/p>\n<\/div>\n

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A doctor checking comatose COVID-19 patients for signs of a stroke instead stumbled onto a new clue about how the virus may harm the lungs — thanks to a test that used tiny air bubbles and a robot.Dr. Alexandra Reynolds, a neurologist at New York\u2019s Mount Sinai Health System, initially was baffled as she tracked…<\/p>\n","protected":false},"author":1,"featured_media":65742,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"tdm_status":"","tdm_grid_status":"","footnotes":""},"categories":[24],"tags":[8241,1086],"class_list":{"0":"post-65741","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-health","8":"tag-bubbles","9":"tag-trail"},"yoast_head":"\n