6 ms·

I think everything that you've said is completely true. However, I'll add that it matters a lot more if you otherwise don't have testing capacity available, or

by zaroth 7y ago

I think everything that you've said is completely true. However, I'll add that it matters a lot more if you otherwise don't have testing capacity available, or if your test has a large false negative rate. China relied heavily on CT-based diagnosis to backstop a lack of available and reliable testing. Another issue is that modern sanitation standards don't really enable using a CT to diagnose an infectious disease. The equipment is far too slow and expensive to truly sanitize, you would have to be willing to just PPE the patient and hope that works out. Again, perhaps better than skipping any diagnostic testing altogether if you don't have any alternative, but certainly not a first-line choice, and ethically questionable if you risk exposing uninfected people.

haldujai 7y ago
Actually you just need to have them wear a mask and wipe down the equipment with standard hospital grade wipes. We know now that COVID-19 is not airborne and is spread by droplets only so this would be routine precautions, unlike TB which we scan routinely and is an airborne pathogen. The problem with CT is we know that the test is completely normal in 50% of patients from day 0-2, and 10-15% of patients up to day 5, and roughly 7-10% of patients up to day 10. These numbers are probably an under representation given how few people with the illness get CT imaging. Additionally as has been stated the findings are considered only somewhat specific, we believe that specificity will decrease as more and more people will eventually get scanned and prove our findings thus far to be false. That is why we (in radiology) currently recommend against the routine use of CT in screening or diagnosis of COVID-19 related illness as a negative test does not mean anything and a positive test is usually noncontributory (clinical diagnosis of COVID-19 infection already made). Additionally, this will rarely affect clinical management. The only potential argument being made is the small subset of people who have viral pneumonia and may theoretically avoid being asked to self-quarantine however I highly doubt in the present climate any infectious patient with a cough will be allowed/think it wise to roam the streets. China has also removed CT from their sixth edition diagnostic manual for this disease as an aside. Source is from STR/ACR, there is a good video below: https://veritastv.org/programs/covid-19 https://veritastv.org/programs/covid-19
- krick 7y ago
  > We know now that COVID-19 is not airborne and is spread by droplets What?! It was only, like, yesterday when I heard that "we know" pretty much the opposite. I'm less and less convinced "we know" anything at all.
  - craz8 7y ago
    There is a medRxiv paper from March 9 that suggests 3 hours half life in the air Anyone who “knows” something is currently wrong, but there is evidence of possible airborne transmission
    - haldujai 7y ago
      Can you provide this link? I could only find: https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v2 https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v... Which does not actually address whether there is airborne transmission of the virus but rather refers to laboratory generated aerosolized particles and viability on various surfaces. If you know otherwise please share as this is in direct contradiction to what various health organizations have been telling HCWs and forms the basis of our hospital’s standard of care which like all other in North America is that airborne precautions are NOT needed except during aerosolized particle generating procedures.
      - Terretta 7y ago
        “Standard of care” is risk managed by a vast bureaucracy of counter-balanced interests. It is not designed to incorporate rapid learning of emerging unknowns. During the exponential introduction of a new disease, the standard of care lags, badly. Repeating “that goes against the basis” or “not needed” doesn’t make sense until the competing interests have settled on a new standard incorporating understanding of the new unknown. Better to follow the emerging research, tailor care, document, and contribute findings back, to optimize the learning curve.
        7y ago

by zaroth 7y ago

haldujai 7y ago

Actually you just need to have them wear a mask and wipe down the equipment with standard hospital grade wipes. We know now that COVID-19 is not airborne and is spread by droplets only so this would be routine precautions, unlike TB which we scan routinely and is an airborne pathogen. The problem with CT is we know that the test is completely normal in 50% of patients from day 0-2, and 10-15% of patients up to day 5, and roughly 7-10% of patients up to day 10. These numbers are probably an under representation given how few people with the illness get CT imaging. Additionally as has been stated the findings are considered only somewhat specific, we believe that specificity will decrease as more and more people will eventually get scanned and prove our findings thus far to be false. That is why we (in radiology) currently recommend against the routine use of CT in screening or diagnosis of COVID-19 related illness as a negative test does not mean anything and a positive test is usually noncontributory (clinical diagnosis of COVID-19 infection already made). Additionally, this will rarely affect clinical management. The only potential argument being made is the small subset of people who have viral pneumonia and may theoretically avoid being asked to self-quarantine however I highly doubt in the present climate any infectious patient with a cough will be allowed/think it wise to roam the streets. China has also removed CT from their sixth edition diagnostic manual for this disease as an aside. Source is from STR/ACR, there is a good video below: https://veritastv.org/programs/covid-19 https://veritastv.org/programs/covid-19

krick 7y ago
> We know now that COVID-19 is not airborne and is spread by droplets What?! It was only, like, yesterday when I heard that "we know" pretty much the opposite. I'm less and less convinced "we know" anything at all.
- craz8 7y ago
  There is a medRxiv paper from March 9 that suggests 3 hours half life in the air Anyone who “knows” something is currently wrong, but there is evidence of possible airborne transmission
  - haldujai 7y ago
    Can you provide this link? I could only find: https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v2 https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v... Which does not actually address whether there is airborne transmission of the virus but rather refers to laboratory generated aerosolized particles and viability on various surfaces. If you know otherwise please share as this is in direct contradiction to what various health organizations have been telling HCWs and forms the basis of our hospital’s standard of care which like all other in North America is that airborne precautions are NOT needed except during aerosolized particle generating procedures.
    - Terretta 7y ago
      “Standard of care” is risk managed by a vast bureaucracy of counter-balanced interests. It is not designed to incorporate rapid learning of emerging unknowns. During the exponential introduction of a new disease, the standard of care lags, badly. Repeating “that goes against the basis” or “not needed” doesn’t make sense until the competing interests have settled on a new standard incorporating understanding of the new unknown. Better to follow the emerging research, tailor care, document, and contribute findings back, to optimize the learning curve.
      - 7y ago