New embarrassingly bad study of ivermectin is a textbook example of “confounding by indication”
In short a retroactive database review found that people w/ COVID did worse if given remdesivir (only given to sick inpatients) than ivermectin (only given to well outpatients)🤔 1/
There are many problems with this “study”.
First it’s generous to even call it a “study.” It’s an *abstract* of a retrospective database review. The whole “article” is less than a page (see below).
They found 1.7 million people w/ COVID. Out of this group they identified 1,072 who received ivermectin (not exactly widely used) & 40k who received remdesivir
The groups were very dissimilar: IVM was 10 yrs younger. They don’t report any comorbidities 3/
Despite the groups being wildly dissimilar, they *somehow* adjusted for potential compounders. (They don’t say how)
Crucially they did NOT adjust for hospitalization status. This means they compared COVID outpatients (on IVM) to COVID inpatients (on remdesivir). 🍎to🍊
4/
The authors are interesting…
The first two are medical students, the 3rd is a plastic surgery resident.
(Nothing wrong with this, though it is weird for the MS not to be affiliated w/ SOM)
The fifth & sixth authors are plastic surgeons. Neither has expertise in ID or COVID 5/
The 4th author @JoseGonzalesZa1 is the head of the ID fellowship at UMiami. He is an actual expert on this topic.
Based on his other work, I’m pretty sure he doesn’t think ivermectin is an effective therapy as this abstract concludes. See translation of one of his articles👇 6/
All of this makes me wonder - did the authors all even read/approve this abstract?
Did the peer reviewers think it was odd that plastic surgeons were doing research on ivermectin for COVID?
7/
I wonder if this abstract was the work of an eager group of students/residents who were inadequately supervised by more experienced researchers
That seems like the only way to explain such an obvious confounder being missed
This must have slipped past peer review at #IMED21 8/
Bottom line:
-this abstract of a retrospective review is fatally flawed due to the confounder of hospitalization (+more). There is no evidence that ivermectin reduces mortality
-it won’t stop fringe docs cashing in on selling ivermectin from promoting this “massive study” 9/9
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New favorite physiology paper: Central Venous Pressure in Space.
So much space & cardio physiology to unpack here including:
- effects of posture, 3g shuttle launch, & microgravity on CVP
- change in the relationship between filling pressure (CVP) & LV size
- Guyton curves! 1/
To measure CVP in space they needed two things:
📼 an instrument/recorder that could accurately measure pressure despite g-force, vibration, & changes in pressure. They built & tested one!
🧑🚀👩🚀👨🚀 an astronaut willing to fly into space with a central line! 3 volunteered! 2/
The night before launch they placed a 4Fr central line in the median cubital vein & advanced under fluoro.
🚀The astronauts wore the data recorder under their flight suit during launch.
🌍The collected data from launch up to 48 hrs in orbit. 3/
Did he have a head CT? What did it show?
Did he have stitches? Tetanus shot?
The NYT ran nonstop stories about Biden’s health after the debate but can’t be bothered to report on the health of someone who was literally shot in the head?
To the people in the replies who say it’s impossible because of “HIPPA” 1. I assume you mean HIPAA 2. A normal presidential candidate would allow his doctors to release the info. This is exactly what happened when Reagan survived an assassination attempt. washingtonpost.com/obituaries/202…
My advice to journalists is to lookup tangential gunshot wounds (TGSW).
Ask questions like:
- what imaging has he had?
- what cognitive assessments?
- has he seen a neurosurgeon or neurologist?
- he’s previously had symptoms like slurred speech, abnormal gait - are these worse?
If you intubate you need to read the #PREOXI trial!
-n=1301 people requiring intubation in ED/ ICU were randomized to preoxygenation with oxygen mask vs non-invasive ventilation (NIV)
-NIV HALVED the risk of hypoxemia: 9 vs 18%
-NIV reduced mortality: 0.2% vs 1.1%
#CCR24
🧵 1/
Hypoxemia (SpO2 <85%) occurs in 10-20% of ED & ICU intubations.
1-2% of intubations performed in ED/ICU result in cardiac arrest!
This is an exceptionally dangerous procedure and preoxygenation is essential to keep patients safe.
But what’s the *BEST* way to preoxygenate? 2/
Most people use a non-rebreather oxygen mask, but because of its loose fit it often delivers much less than 100% FiO2.
NIV (“BiPAP”) delivers a higher FiO2 because of its tight fit. It also delivers PEEP & achieves a higher mean airway pressure which is theoretically helpful! 3/
Results from #PROTECTION presented #CCR24 & published @NEJM.
- DB RCT of amino acid infusion vs placebo in n=3511 people undergoing cardiac surgery w/ bypass.
- Reduced incidence of AKI (26.9% vs 31.7% NNT=20) & need for RRT (1.4% vs 1.9% NNT=200)
Potential game changer!
🧵 1/
I work in a busy CVICU & I often see AKI following cardiac surgery.
Despite risk stratification & hemodynamic optimization, AKI remains one of the most common complications after cardiac surgery with bypass.
Even a modest reduction in AKI/CRRT would be great for my patients. 2/
During cardiac surgery w/ bypass, renal blood flow (RBF) is reduced dramatically. This causes injury, especially in susceptible individuals.
But what if we could use physiology to protect the kidneys?
Renal blood vessels dilate after a high protein meal increasing RBF & GFR! 3/
77 yo with respiratory distress, RR 30, SpO2 80% on non-rebreather at 15 lpm
CXR & TTE are unrevealing
pH 7.58 / PaCO2 24 / PaO2 >500 / HCO3 22
MetHb 0% CarboxyHb 0%
The ABG looks like this:
The answer is sulfhemoglobinemia.
Sulfhemoglobinemia is a *permanently* modified hemoglobin associated with exposure to TMP/SMX, dapsone, phenazopyridine, & other amino & nitro compounds.
It has an altered oxy-hemoglobin dissociation curve.
2/
Sulfhemoglobinemia is easily confused with methemoglobinemia. Both have very dark colored blood & present with cyanosis. Diagnosis typically requires a specialized lab.
Spoiler: you may have heard that SulfHb is green. It isn’t really. You’re thinking of Vulcans’ blood.