April 21, 2020 - STAT

Why don’t some coronavirus patients sense their alarmingly low oxygen levels ? | Science | AAAS
▻https://www.sciencemag.org/news/2020/04/why-don-t-some-coronavirus-patients-sense-their-alarmingly-low-oxygen-le

https://www.sciencemag.org/sites/default/files/styles/article_main_large/public/hypoxia_1280p.jpg?itok=xeFCKkhf

La formation de caillots dans les vaisseaux sanguins (thrombose) pourraient être responsable et les anticoagulants pourraient donc être efficaces.

Hypotheses about what causes it are emerging. Many doctors now recognize clotting as a major feature of severe COVID-19. Negri thinks subtle clotting might begin early in the lungs, perhaps thanks to an inflammatory reaction in their fine web of blood vessels, which could set off a cascade of proteins that prompts blood to clot and prevents it from getting properly oxygenated.

Negri developed this idea after treating a woman whose breathing troubles coincided with circulatory problems in her toes. Negri’s team gave the woman heparin, a common blood thinner, and not only her toes but her breathing recovered. Negri wondered whether heparin could boost patients’ low oxygen levels regardless of whether they were struggling to breathe. On 20 April, she posted a preprint detailing her hospital’s experience with 27 COVID-19 patients. Patients with hypoxia received heparin, and the dose was increased if they had elevated levels of D-dimer, a blood marker of excess clotting.

One of the 27 was lost to follow-up after transferring to another hospital. But 24 others are recovering—including six of eight who needed mechanical ventilation, a better rate of positive outcomes than has been reported elsewhere. Two remain critically ill. Negri is now planning to follow more patients. And several clinical trials elsewhere will test whether blood thinners can prevent or treat complications of severe COVID-19, including respiratory problems.

Strayer finds it reasonable to imagine that hypoxia emerges because “small blood vessels of the lung are being showered with clots.” His own hospital and others are beginning to test many admitted COVID-19 patients for markers of excess clotting and treat those who show it with blood thinners. But, “It is simply not known” whether clotting causes happy hypoxia, Strayer says. There are other possibilities. Recent imaging of a hypoxic patient showed “almost waxy-looking film all around the lungs,” Caputo says. “I don’t know what is actually going on pathophysiologically down there.”

Réponse de l’ami réanimateur dans un CHU parisien quand je lui ai envoyé le lien :

« Mais depuis le début les consignes ont été de bien anti coaguler les covid du fait des thromboses !! De toutes façon le ttt était symptomatique avec de l’héparine curative »

Moi : « Donc c pas la panacée ? “

Ami : “ Non malheureusement !! Mais ça fait partie du ttt de base ”

Moi : “ Donc héparine curative systématique ?”

Ami : “ Chez tous les intubés !! Et préventive même chez les non hospitalisés ”

Ici une étude qui trouve une mortalité nettement diminuée lors de l’emploi d’anticoagulants chez les patients COVID-19 intubés avec ventilation assistée.

Le MGH en invalide les résultats.

▻https://seenthis.net/messages/851380

Autopsy Findings and Venous Thromboembolism in Patients With COVID-19 | Annals of Internal Medicine…
▻https://seenthis.net/messages/851402

Petite série autopsique prospective qui confirme l’importance de la thrombose, veineuse notamment (avec embolie pulmonaire secondaire), comme complication et cause des décès.