Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.

This is the legacy version of twitter.com. We will be shutting it down on June 1, 2020. Please switch to a supported browser, or disable the extension which masks your browser. You can see a list of supported browsers in our Help Center.

  • Home Home Home, current page.
  • About

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
s_r_constantin's profile
Sarah Constantin
Sarah Constantin
Sarah Constantin
@s_r_constantin

Tweets

Sarah Constantin

@s_r_constantin

Math/ML/data-science person now working on solving aging...and helping with COVID19?! Founder, LRI and Daphnia Labs. Married to @oscredwin

Be
srconstantin.posthaven.com
Joined February 2019

Tweets

  • © 2020 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Imprint
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      Ordinarily, when not enough oxygen is getting to (parts of) the lung, due to lung damage (as from pneumonia), there's a thing called hypoxic pulmonary vasoconstriction. Arteries pumping blood to fucked-up alveoli become narrower, so more blood can pick up oxygen from good alveoli

      1 reply 1 retweet 3 likes
      Show this thread
    2. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      This is called ventilation/perfusion (V/Q) matching. Failure is called V/Q mismatch. You have blood flow without oxygen, or oxygen without blood flow.

      1 reply 0 retweets 3 likes
      Show this thread
    3. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      The sensor that triggers hypoxic pulmonary vasoconstriction is in the mitochondria and involves the NDUFS2 gene.

      1 reply 0 retweets 3 likes
      Show this thread
    4. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      The theory here is that this sensing mechanism goes awry in COVID19. Pulmonary arteries don't constrict in response to poor oxygenation. Patients don't feel a sensation of breathlessness even though they're hypoxemic, because the usual responses to low O2 aren't working.

      1 reply 1 retweet 4 likes
      Show this thread
    5. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      Why doesn't buildup of CO2 cause an increased respiratory drive though? Authors don't say. maybe it's obvious but I'm confused.

      2 replies 0 retweets 3 likes
      Show this thread
    6. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      This article also has a model of what's going on that may clarify.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7154064/ …

      1 reply 0 retweets 2 likes
      Show this thread
    7. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      What do we see in COVID19 patients with "silent hypoxemia"? 1.) Normal lung elastance -- normal amount of gas gets into lungs.

      1 reply 0 retweets 2 likes
      Show this thread
    8. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      2.) Low V/Q ratio: too much perfusion relative to ventilation, probably due to loss of hypoxic vasoconstriction.

      1 reply 0 retweets 2 likes
      Show this thread
    9. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      3.) and 4.) low lung weight and recruitability: only a small amount of lung tissue is damaged (and thus filled with liquid or "recruitable" by forcing the alveoli open with ventilatory pressure).

      1 reply 0 retweets 3 likes
      Show this thread
    10. Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      So we only have a little bit of damage to the lung, but the circulatory system's not routing around it normally, so you have SUPER bad hypoxemia.

      1 reply 1 retweet 2 likes
      Show this thread
      Sarah Constantin‏ @s_r_constantin May 6
      • Report Tweet
      • Report NetzDG Violation

      what this article says is that these "silent hypoxemic" patients DO have an increased respiratory drive; their breathing rate and minute volume (gas inhaled/exhaled per minute) is way up to compensate.

      10:58 AM - 6 May 2020
      • 4 Likes
      • alex k Natanael, tech janitor Justin Kaeser 🧼👏💦🏠😷 @micahstubbs
      1 reply 0 retweets 4 likes
        1. New conversation
        2. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          They're not feeling dyspnea due to CO2 buildup because they're not actually building up CO2; they're ventilating plenty via increased respiratory rate. And indeed they tend to have low measured blood CO2 levels.

          1 reply 0 retweets 2 likes
          Show this thread
        3. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          V/Q mismatch impairs BOTH getting O2 in and getting CO2 out. But it usually results in low O2 and *normal*, not high, CO2, since any rise in CO2 results in more respiratory drive. (at least that's what Wikipedia says. https://en.wikipedia.org/wiki/Ventilation/perfusion_ratio …)

          1 reply 0 retweets 2 likes
          Show this thread
        4. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          (I'm new to all this stuff, bear with me.)

          1 reply 0 retweets 2 likes
          Show this thread
        5. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          Why doesn't "silent hypoxemia" stay harmless? If I understand the article correctly, this is because you're breathing so much more that there's an increase in "inspiratory intrathoracic pressure", and this damages the lung, causing "P-SILI", or patient-self-inflicted lung injury.

          1 reply 2 retweets 3 likes
          Show this thread
        6. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          If you make a sheep hyperventilate, it damages its lungs, for instance.https://link.springer.com/article/10.1007/BF00255628 …

          1 reply 0 retweets 4 likes
          Show this thread
        7. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          Now patients who previously had a *little* bit of lung damage have a LOT of lung damage. And therefore it looks more like typical ARDS: low compliance, high lung weight, high recruitability, and much bigger lung lesions visible on a chest CT.

          1 reply 1 retweet 4 likes
          Show this thread
        8. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          logically this implies: keep patients from hyperventilating while they're still in "silent hypoxemia" so they don't breathe so much they progress to full-blown severe ARDS.

          1 reply 1 retweet 5 likes
          Show this thread
        9. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          how do you do this? it looks like it's a matter of debate right now. one thing I've seen in a couple papers is "use work of breathing to determine when to intubate". Patient can't breathe too hard if a machine's breathing for them!

          2 replies 0 retweets 2 likes
          Show this thread
        10. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          The big conclusion the COVID19 paper draws about patients with low oxygen but no dyspnea is *give 'em lots of oxygen.* Tradeoffs are more ambiguous about PEEP.

          1 reply 0 retweets 2 likes
          Show this thread
        11. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          The other conclusion is that you want to intubate when the inspiratory pressure swings are starting to get big, as controlling the breathing rate can *prevent* additional lung injury.

          1 reply 0 retweets 2 likes
          Show this thread
        12. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          "As esophageal pressure swings increase from 5 to 10 cmH2O—which are generally well tolerated—to above 15 cmH2O, the risk of lung injury increases and therefore intubation should be performed as soon as possible."

          1 reply 0 retweets 3 likes
          Show this thread
        13. Sarah Constantin‏ @s_r_constantin May 6
          • Report Tweet
          • Report NetzDG Violation

          Also, if we could figure out *how* COVID19 blocks hypoxic vasoconstriction, and find a way to make it *stop*, those "silent hypoxemic" patients could get their V/Q back to normal, and thus would no longer be hypoxemic (since they don't have much lung damage to begin with.)

          0 replies 1 retweet 3 likes
          Show this thread
        14. End of conversation

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2020 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Imprint
        • Cookies
        • Ads info