The Latest in Critical Care, 8/21/23 (Issue #11)
The Latest in Critical Care, 8/21/23 (Issue #11)
High vs. low oxygenation targets in mechanically ventilated patients.
Further evidence from the ICONIC trial suggests oxygenation that seems “good enough” in vented patients, probably is.
Authors randomized 664 patients receiving mechanical ventilation to receive oxygen to a target paO2 55-80 mm Hg (low oxygenation) or 110-150 mm Hg (high oxygenation). At 28 days, 38% of the low-oxygenation patients had died, vs. 35% of the high-oxygenation patients (risk ratio 1.11, with a 95% confidence interval of 0.9-1.4, P=0.30). There were no significant differences in adverse events.
The study was stopped in November 2021 due to the Covid-19 pandemic, at just over half of its intended enrollment, reducing its power. I’m not enough of a statistician to say how this affects the strength of its conclusions, and whether full enrollment could have changed them.
However, it’s unlikely. A larger trial of 2500 patients published in NEJM in 2022 showed no difference in outcomes among patients ventilated with high vs. low oxygenation strategies.
A meta-analysis also found no clear difference in outcomes between liberal and conservative oxygenation strategies, with low certainty in the results.
One trial that did suggest a possible benefit of low-oxygenation targets was also stopped early, due to an earthquake. Maybe Mother Nature is telling us she’s been asked this research question quite enough, thank you? Read in AJRCCM and NEJM
More reasons not to rely on procalcitonin testing over clinical judgment.
Biomarkers always seem awesome when they first become available, seemingly bringing us one step closer to Star Trek tricorders and nanobot blood-scrubbers. Then the reality of their limitations sets in, and being left behind here on Earth with our old-timey clinical skills, a few Petri dishes, and Abraham Verghese doesn’t sound so bad.
Procalcitonin is the latest biomarker to come out battered after several years of real-world use. A recent data analytic study examining procalcitonin’s use in 75,000 patients shows that it was only 68% sensitive at ruling out bloodstream infection, even at a low cutoff point of 0.5 ng/mL. (Remember SPIN vs. SNOUT—highly sensitive tests are good at ruling out.) Performance was much higher for pneumococcal sepsis (which usually presents with more severe illness, rendering the biomarker less useful).
Worse, procalcitonin use didn’t result in significantly lower prescription of empiric antibiotics, although guiding safe withholding and de-escalation of antibiotics is its primary purpose. Surely this test still has utility, but I’m not sure what it is. Read in Critical Care Medicine
In the News
CDC and WHO are tracking a new highly mutated Covid variant. BA2.86, previously seen in Denmark and Israel, was recently isolated from an infected patient at University of Michigan. It has enough genetic shift from Omicron that it would represent a change as significant enough as the displacement of Delta by Omicron. The cases thus far have been mild, according to news reports.
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Moderna and Pfizer both say their mRNA vaccines are effective against the new most dominant Covid subvariant, EG.5.1, dubbed Eris. EG.5.1 shares almost all the same spike proteins of the XBB subvariant the new shots are based on.
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The legal battles over the definition of “misinformation” and the limits of physician speech and behavior during the Covid pandemic are moving through courtrooms. The Maine medical board suspended Dr. Meryl Nass’s medical license in January 2022 after she refused to stop prescribing ivermectin and hydroxychloroquine, including by telemedicine, and publicly cast doubt on the safety and effectiveness of the mRNA vaccines. She allegedly falsely told a pharmacist a patient had Lyme disease, to justify a hydroxychloroquine prescription.
The medical board took the unusual step of requiring her to submit to a neuropsychiatric evaluation, although there was no obvious reason, in order to harass her and harm her reputation (she alleges).
Nass is now suing the medical board for violating her First Amendment rights to freedom of speech.
There are two questions here: one, is publicly speaking out against efficacious vaccines protected speech for a physician during a pandemic, and if not, how should this behavior be addressed?
This may deserve a separate post, but first, I’m interested in what you think:
The Latest in Critical Care, 8/21/23 (Issue #11)
The question in the poll refers to 2021, during the initial pandemic waves with virulent variants and overwhelmed medical servies..... Speaking out against vaccination then, is different from speaking against it now. The variants have changed and so has the risk benefit ratio. Hydroxychloroquinine and ivermectin....really??