#CriticalCare non-COVID teaching case:
An elderly man is admitted to the surgical ICU for monitoring after an uncomplicated kidney transplant. You notice this funny pattern on his arterial line tracing. What’s going on here? #FOAMcc#FOAMed 1/
What’s going on here?
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This is pulsus alternans: an alternating strong & weak pulse.
Based on the A-line tracing POCUS was performed that reveled a markedly reduced EF. Coronary angiography showed no obstruction and a diagnosis of stress CM was made. The patient recovered with medical therapies.
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At first glance, differentiating pulsus alternans from exaggerated pulse pressure variation (PPV) can be tricky
*pulsus alternans occurs every other beat
*PPV occurs with the respiratory cycle
Slowing down the display can differentiate: This is what increased PPV looks like 4/
Pulsus alternans was first described by Traube in 1872.
Despite 150 yrs of research, the mechanism is not precisely known.
There are two theories, related to either beat-to-beat variation in pre-load or in contractility.
The *pre-load theory* is that impaired contractility (causing a weak pulse) leads to an increased end diastolic volume at the next systole. With more filling, the next contraction ejects more blood (causing a strong pulse) due to the Frank-Starling principle. 6/
The alternative *contractility theory* is that residual cytoplasmic Ca2+ after a weak systole causes a stronger cardiac contraction on the next beat.
Whatever the mxn, pulsus alternans is associated with poor systolic function.
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🥡Points:
🫀Pulsus alternans on an arterial line tracing can be a useful diagnostic clue for decreased systolic fxn
1⃣📟 See this new ICU OnePager on arterial Lines for more onepagericu.com 8/
📚Historical/literary note:
DH Lawrence beautifully describes Pulsus Alternans in Sons and Lovers:
"…he felt her pulse. There was a strong stroke and a weak one, like a sound and its echo. That was supposed to betoken the end."
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Tragic news today about former president Biden's prostate cancer diagnosis. I wish him well.
As someone who follows presidential health reporting, I noticed something odd: unlike his predecessors, Biden's physician's never reported PSA.
How to interpret this absence? A🧵 1/
There are two possibilities:
1️⃣ Biden’s PSA was never checked
2️⃣ Biden’s PSA was checked but it wasn't reported
Strictly speaking, not checking PSA could be a medically correct option. Whether or not to test PSA is a complex question and is not the topic of this thread.
2/
Like many VIPs, presidents tend to have excessive testing that is not always strictly evidence-based.
For example, Bush 43 had an exercise treadmill test and a TB test for no apparent reason.
In honor of #MayThe4thBeWithYou let's consider the most difficult airways in the Star Wars universe:
1. Darth Vader
Species: human
Vader presents several challenges: Vent dependent at baseline, airway burns from Mustafar, limited neck mobility.
Discuss GOC before saving him
2. Fodesinbeed Annodue
Species: Trog
All airways require teamwork, but intubating Fodesinbeed Annodue's two heads really will require two operators.
Consider double simultaneous awake fiberoptic intubation
Be sure to consent both heads.
You will never find a more wretched hive of scum & challenging airways than Mos Eisley (except maybe at Jabba's)
3.Greedo
Species: Rodian
Micrognathia, posterior airway, no nasal intubation, green skin so no pulse ox
Approach: VL + bronchoscope. Intubate quickly (shoot first)
Every year, there is a predictable spike in fatal car accidents, medical errors, & heart attacks.
It’s estimated that there are thousands of excess deaths, a 1% increase in energy consumption, & billions of dollars in lost GDP.
The cause? Daylight savings transitions.
🧵
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Earth's axis of rotation and orbital axis are not precisely aligned. The 23.5 degree difference - 'axis tilt' - gives us our seasons and a noticeable difference in day length over the course of the year.
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For millennia this seasonal variation was an accepted fact of life.
In 1895, George Hudson, a New Zealand entomologist, was annoyed that less afternoon light meant less time for bug collecting.
He realized that clocks could be adjusted seasonally to align with daylight.
Unlike other Trump moves, this is arguably GOOD news for researchers!
If the NIH budget is unchanged (a big if), this allocates more money to researchers; if you go from an indirect of 75% to 15% it means you can fund 3 grants instead of 2.
Between 1947 and 1965, indirect rates ranged from 8% to 25% of total direct costs. In 1965, Congress removed most caps. Since then indirects have steadily risen.
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A lot of indirects go to thing like depreciation of facilities not paying salaries of support staff.
This accounting can be a little misleading.
If donors build a new $400m building, the institution can depreciate it & “lose” $20m/year over 20 years. Indirects pay this.
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🚨Apparently all NIH Study Sections have been suspended indefinitely.
For those who don’t know, this means there won’t be any review of grants submitted to NIH
Depending on how long this goes on for, this could lead to an interruption in billions in research funding.
With a budget of ~$47.4B, the NIH is by far the biggest supporter of biomedical research worldwide.
Grants are reviewed periodically by committees of experts outside of the NIH.
When these study sections are cancelled, it prevents grants from being reviewed & funded.
Hopefully this interruption will be brief (days)
A longer interruption in study sections (months) will inevitably cause an interruption in grant funding. This means labs shutdown, researchers furloughed/fired, & clinical trials suspended. This will harm progress & patients!