Shivakumar Mutnal

MD, IFCCM, ICU doc, saving lives, athiest but believe in Work is Worship/ #FOAM #FOAMcc #POCUS..

[Shivakumar Mutnal @drshivkumar]

For people who keep asking what specialty are you in??
Also, how important is an intensivist in a Hospital..

[Dr. Chacón-Lozsán F .'. @franciscojlk]

🫁 Why I always ask for paired blood gases! CO2 and hemodynamics 🧪

For years, we have relied on:

▪️ Lactate
▪️ ScvO₂ / SvO₂
▪️ Clinical perfusion

But all of them share a critical limitation:

👉 They do not reliably detect ongoing tissue hypoperfusion

⚠️ The problem

You can have:

✔️ Normal ScvO₂
✔️ Decreasing lactate
✔️ “Stable” hemodynamics

…and still have microcirculatory failure

👉 This is where CO₂ enters the game

🧠 The physiology in short

CO₂ behaves differently from oxygen:

➡️ ~20x more diffusible than O₂
➡️ Accumulates when flow is insufficient
➡️ Reflects flow adequacy, not just oxygenation

👉 Pv-aCO₂ ≈ inverse of cardiac output

🔥 What the CO₂ gap really tells you

🟢 Pv–aCO₂ < 6 mmHg → Likely adequate flow

🔴 Pv–aCO₂ ≥ 6 mmHg → Suggests low flow / impaired perfusion

BUT:

❗ It is NOT a marker of hypoxia alone
❗ It is a marker of flow–metabolism mismatch

⚡ The real upgrade: the CO₂/O₂ ratio

👉 Pv-aCO₂ / Ca-vO₂

This is the missing piece.

✔️ Approximates respiratory quotient
✔️ Detects anaerobic metabolism
✔️ Reacts faster than lactate

📈 >1 = ongoing anaerobic metabolism

🚨 Clinical implications

🩸 Septic shock

High CO₂ gap despite ScvO₂ >70% → hidden hypoperfusion

Persistent Pv–aCO₂ ≥6 mmHg → ↑ mortality

🫀 Fluid responsiveness

↓ Pv–aCO₂ after fluids → likely responder

🫁 Weaning failure

↑ CO₂ gap during SBT → inadequate DO₂ vs VO₂

🏥 Post-op patients

Elevated CO₂ gap predicts complications better than lactate

❌ Common mistakes

❌ Using lactate alone
❌ Ignoring normal ScvO₂ “false reassurance”
❌ Interpreting CO₂ gap without context (pH, Hb, ventilation)
❌ Treating numbers instead of physiology

🚀 Modern hemodynamic approach

We should integrate:

1. Macrocirculation → MAP, CO

2. Oxygen markers → ScvO₂

3. Metabolic markers → Lactate

4. Flow markers → Pv–aCO₂

5. Anaerobic markers → Pv–aCO₂ / Ca–vO₂

👉 Not one variable
👉 A physiology-driven bundle

🎯 Take-home

CO₂ is not a waste product.

👉 It is a real-time marker of perfusion adequacy
👉 It detects what oxygen variables miss
👉 It bridges macro and microcirculation

📚 Mallat J et al. (2025)
Annals of Intensive Care
DOI: 10.1186/s13613-025-01569-2

[Ray Dalio @RayDalio]

It's now happening. The existing fiat monetary order, the domestic political order, and the international geopolitical order are all breaking down, so we are at the brink of wars. It all is happening because of the Big Cycle that is driven by the five big forces I've described repeatedly and laid out in detail in my book and Youtube video titled Principles for Dealing with The Changing World Order. You can find the video linked in the comments below.

[Ross Prager @ross_prager]

(1/x) Andromeda-Shock 2 was just published in JAMA and is the most important septic shock trial in the past DECADE.

They found that phenotyped resuscitation improves the composite outcome of mortality, vital support, and hospital LOS.

Here's how you can apply this protocol to your practice 👇

[Aravind Palraj @Rheumat_Aravind]

🧵 Hyponatremia: A Stepwise Approach:

Tweet 1:
Sodium is small, but its imbalance can be catastrophic.
Hyponatremia = one of the most common electrolyte problems in medicine.
👉 Here’s a stepwise, practical approach every clinician should know ⬇️
@IhabFathiSulima @DrAkhilX #MedTwitter #MedEd

[M Velia Antonini @FOAMecmo]

Antibiotic therapy for severe bacterial infections:
🔍 epidemiology of severe infections: community vs hospital-acquired, L/MICs
⏱️ when to start and NOT to start antibiotics?
🚧 specific issues: migrants/travellers, emerging infectious diseases, Immunocompromised patients
🧫 role of microbiology lab & rapid diagnostic tests
💉initial antimicrobial selection
💉monotherapy vs combination therapy
🩺 role of clinical pharmacist: PK/PD principles; drug-drug interactions; TDM: when & how
⚠️ when antimicrobials are harmful
⏱️ when to stop ABTs/optimal duration of therapy
🔮 area for future research
🔗 https://t.co/gW5VsYGHfU

‼️ PS check supplementary file for suggested dose/administration

[Eddy J. Gutierrez, MD @eddyjoemd]

Delirium is amongst the most frustrating things our patients and their families experience in their ICU stay. This table could prove helpful in demonstrating to them why their behavior is as it is. 🎩 tip to the authors.
https://t.co/Sfr6vCn6le

[Turning the Tide @Turningthe_Tide]

1/ 💉 Resuscitation fluids – life-saving in true hypovolaemia.

Give them for the wrong reason and you harm patients.

We’ve covered maintenance &amp; replacement fluids — now the trilogy ends with resuscitation. Here’s how to get it right. #MedX

[Shivakumar Mutnal @drshivkumar]

@Fluid_Academy @icu_nivare @Manu_Malbrain @avkwong @drPaulElbers @Prof_XMonnet @Drnasap @OrlandoRPN @Wilkinsonjonny One size never fits any patient in ICU. This sentence is atleast a decade old. And in TBI atleast 15 yrs old for rest of the fluids other than good old saline.

[De Christian Life @DeChristianLife]

Having daughters prolong a father's

[Ashley Miller @icmteaching]

1/
Most people think the heart drives circulation.
But what if that’s backwards?
Anderson’s model flips the whole idea of cardiac output on its head — and it changes how you think about fluid, flow, and failure.
🧵👇
#physiology #FOAMed #MedTwitter #criticalCare #cardiacOutput

[Ambarish Satwik @AmbarishSatwik]

What the salad tried to do to us.

The first ambition of any plant is to make itself uneatable. Long before anything clever walked on earth, plants settled on poisoning anything with a mouth. If you can’t run, you better taste terrible. The only way to stay alive was to face your predator (dinosaur, beetle, goat, man) with chemistry. Plants got clever in the only way available to them. They made toxins, astringents, enzymes, fibrous defences. Which made them and their parts bitter. Also indigestible, and outright poisonous.

In evolutionary terms, it was a cunning move. Not that the plant knows anything about cunning. But the natural consequence was deterrence. You bite, you suffer. You learn. You stop biting.

Humans responded in the human way. By using fire and other things. We boiled, we burned, we soaked, we crushed, we fermented. We pickled. We found ways to take the bitter poisonous offerings of plants to our hungers. We hacked our own biochem, made over 50 types of CYP450 enzymes. They’re fascinating. A plant toxin molecule (alkaloid, glucosinolate, cyanogenic glycoside, saponin etc) is like a greasy stain. CYP450s act like detergent: They grab it, break it apart, make it dissolve in water, and wash it away. Cats don’t have a lot of this stuff. The thiosulfates in a couple of cloves of garlic can trigger a dangerous oxidative crisis in cat blood. About four cloves (of garlic) can be a potentially lethal dose. A tiny amount of solanine from a raw potato can sicken and kill a rabbit. Without a particular kind of P450, a potato would be your last meal.

We figured out how to eat the enemy. And then we got kinky about it. Our tongues learned to relish the sting. And the rot. We started liking the burn and the bitterness. We started having poison for the plot. Hot sauce. Tannins. Coffee so strong it peels paint. Flavour is a toxin we’ve come to applaud.

Plants spent a hundred million years trying to kill us. We’ve spent a hundred million years learning to savour their attempts. That’s the story, give or take a few famines and a few million deaths.

[Shivakumar Mutnal @drshivkumar]

@ActusDei @Iamsamirarora Ppl get offended whn it is directed to their motive despite that being in a honest way to educate larger crowd. Keep doing the gud work Neil. Ppl like him and his followers who were flying all these yrs wit India growth story, keeping cash for crash, etc are licking their wounds

[Shivakumar Mutnal @drshivkumar]

@WeekendInvestng @DalrympleWill one of the pioneers of Indian history. @EmpirePodUK is must for history buffs

[Mohan Sai Gudela, DM @drmohansai]

2024 has been a great year for Neurocritical Care!
Here are the Top 10 Neurocritical Care review articles to read before the year ends 👇
#NeurocriticalCare
@NCSIofficial @kgupta71293

[JAMA @JAMA_current]

#CCRdownunder attendees, check out these findings from this year's @CritCareReviews meeting 🧵:

In critically ill adults w/ suspected sepsis, antibiotic regimens were reduced when guided by measurement of procalcitonin but not by C-reactive protein. https://t.co/mH3ZSHUGCr

[Nick Mark MD @nickmmark]

The #ADAPTtrial results are interesting…

Compared to SOC, Procalcitonin guided antibiotic therapy resulted in:
- FEWER antibiotic days: 10.7 vs 9.8 (p=0.01) BUT
- HIGHER 28 day mortality: 19.4% vs 20.9% (p=0.02) though less than the pre-specified non-inferiority margin

A🧵
1/

[Critical Care Reviews @CritCareReviews]

➡️ 8 major critical care trial results live from Melbourne

➡️ Full free livestream

➡️ Tuesday &amp; Wednesday, December 10th &amp; 11th

➡️ Times are UTC +11

➡️ https://t.co/sGWuTjv0BC

[Saad Ur Rahman @SaadUrRahman55]

Takeaways from #AHA2024. Late breaking trials - take home points
@AHAScience

1. BPROAD Trial: Intensive treatment targeting SBP ≤120 mmHg reduced the incidence of MACE at 5 years vs. standard treatment targeting ≤140 mmHg in patients with type 2 diabetes and hypertension with elevated CV risk.

[Tim Denning @Tim_Denning]

This man destroyed wokeism:

Naval Ravikant.

He was an early investor in Notion, Twitter &amp; Uber &amp; is worth $600M+

He's been on fire lately on X.

Here is Naval's updated philosophy:

[Tim Denning @Tim_Denning]

12. "It’s rare for intelligence and drive to intersect in one person. When they do, look out."

Hang around obsessed people.

Judge intelligence based on whether people get what they want in life.

Memorizing information = Stupidity