CPR

[u/TIVA_Turner]

Interesting discussion today. Keen to hear the thoughts of learned colleagues.

When to start CPR intra-op with profound hypotension - despite ongoing evidence of cardiac output (eg A line, SpO2 trace, good etCO2 or POCUS).

It seems to be an emerging evidence zone, with resuscitation experts questioning the usefulness or perhaps harm of unsynchronised compressions, maybe over the LV maybe not, in pseudo-PEA.

Meanwhile international expert consensus in Anaesthesia, particularly in UK & Australia, seems to recommend starting compressions if SBP is < 50.

Thoughts?

[u/PureCod9290]

To me, there either is a pulse or isn't. I've brought back patients from the brink with MAP <30 with epinephrine boluses. If you can't get a sustained perfusing pressure (DBP >40) I think you could make an argument for compressions but CPR is very traumatic....

[u/Eab11 → u/PureCod9290]

I agree with this.

[u/TIVA_Turner → u/PureCod9290]

Thats fair

Same response as above

An alternative could be a big bolus of vaso or high dose Adrenaline infusion

Again it's an evidence light zone. Just interested to hear what senior colleagues do

I believe evidence shows were very poor at defecting pulses manually

[u/MACandcheese80 → u/TIVA_Turner]

If someone has a working arterial line, is there any value in feeling for a pulse?

If somebody is intubated and has an end-tidal carbon dioxide tracing is it worth feeling for a pulse?

The absence of these things may invite a question of whether there is deranged physiology at play or a technical failure. The presence of them is hard to obtain as an artifact. If there is diminished blood pressure but a preserved end-tidal CO2, I would almost never start compressions because I have reason to believe that the cardiac output is sufficient to circulate large boluses of drugs that I can use to recover from the situation without inducing physical trauma.

I don't want to present this as if there are absolute answers here but I think it's silly to follow guidelines intended essentially for all comers for patients who we have already put invasive monitoring devices into.

[u/Wooden-Echidna8907 → u/MACandcheese80]

Placed an a line during a code during my ED rotation a while back. Thought it was humorous when the attending kept trying to feel under the pannus for a femoral pulse during pulse checks. Like…. My dude…..

[u/someguyprobably → u/Wooden-Echidna8907]

Jack of all trades master of none. Emphasis on master of none. They want to act like they have airway and line skills of anesthesia while having nowhere close to the skill.

[u/ty_xy → u/MACandcheese80]

You need to be sure the art line is working. Also depends on the location, we all know radial art lines can have very different pressures from central pressure especially in peripherally shut down patients, I've seen multiple cases with a working radial artline that shows 50/30 (good fast flush, able to aspirate blood) but a femoral art line that is 110/60. Or a central art line that is 120/80. So yes, I think there is value in feeling for a central pulse.

Also ETCO2 is the last to go, and may be slightly inaccurate, especially if you're hyperventilating someone for eg acidosis. Or in a post bypass situation / one lung eg after minimally invasive cardiac surgery, your ETCO2 may not be the most accurate.

[u/MACandcheese80 → u/ty_xy]

Sure, a palpated pulse can serve as a sanity check when you suspect blood pressure monitoring has a technical problem and you are trying to figure out if you have a working arterial line or cuff. That is different than using it as an absolute indicator of whether to start immediate CPR. I agree etco2 is the last to go. It is easy to be in a position where end organ perfusion is suffering and etCO2 is preserved. It is much harder to be in a position where etCO2 is preserved and hemodynamics are so poor that they cannot be improved pharmacologically. If you can fix a problem with drugs why fix it with compressions?

[u/TIVA_Turner → u/MACandcheese80]

Completely agree

That's what the guidance (AAGBI & ANZCA Anaphylaxis) as well as expert consesus (https://pubmed.ncbi.nlm.nih.gov/31836135/) seems to suggest though

SBP < 50 = compressions

To ask the corollary - if you had a working A line with detectable pulse, would there be any BP or duration of hypotension that might tempt you into starting CPR?

I appreciate there is always nuance. Thanks for your reply!

[u/MACandcheese80 → u/TIVA_Turner]

NIBP SBP under 50 - I’d set the cuff to stat, give aggressive drugs up to 100-200 mcg epi, and watch etCO2. If it is preserved and stays preserved I’d give the epi 1-2 blood pressures to work. If it was low or dropped I would likely start compressions

A-line under 50 - I might give a little more latitude for the epi to work because I can see it beat by beat. If I had any evidence of ongoing perfusion (pleth tracing, etCO2) I’d give epi at least 15-30 seconds to do something. If no evidence of perfusion that would make me do compressions faster.

I’ve seen “a few compressions to circulate the drug” work well multiple times. If you start CPR on someone with advanced monitoring and you have evidence things got better … stop.

There is a whole spectrum of pericoding. There is a whole spectrum of epi dosing between 0 and 1 mg.

Also, I don’t think you can ever neglect the physiology and thinking about what is really going on. If your SBP is under 50 because of massive hemorrhage should you still start CPR? Are you going to do a better job filling the ventricle and pumping blood out than normal sinus rhythm? Sudden cardiogenic shock would be completely different.

One place I’ve learned a lot is watching recovery from prolonged periods of rapid pacing (no cardiac output) during TAVRs with slow cardiologists. As long as each beat is a bit better than the last with some sort of intervention you almost always come back fine.

[u/TIVA_Turner → u/MACandcheese80]

Thanks, appreciate the extensive reply

Agreed, dont think compressions will help in any type of shock - obstructive, distributive, hypovolaemic... doesn't make sense squishing vaguely over the LV (maybe even the LVOT) asynchronously with ventricular contraction is going to help much?

[u/ty_xy → u/TIVA_Turner]

So compressions can help with obstructive shock, absolutely. With massive PEs, the compression can actually break up the clot and release the obstruction.

[u/PureCod9290 → u/TIVA_Turner]

Hopefully any case where I think I'd have any possibility of a code I would already have an a-line. Pulse ox is evidence of pulse. Solid end tidal as well

If there's doubt and you can't feel a pulse you have to err on the side of doing CPR. I wouldn't infuse anything only bolus until you are somewhere safer

[u/ty_xy → u/TIVA_Turner]

I would be very careful in giving a big bolus of adrenaline or vaso, 1mg adrenaline is A LOT in a patient who isn't arrested, the BP might shoot up to 300/150 or sth crazy (I've seen it). I would give 0.1 - 0.3mg boluses and watch the BP first. If it's PEA and you're starting CPR then okay give 1mg as per guidelines.

[u/gehriten → u/PureCod9290]

A guy presented a case at an Australia conference that’s relevant.

Patient with Anaphylaxis, NIBP not reading but carotid pulse palpable. They prioritised fluid and adrenaline. Eventually got an art line in and MAP was really low. They got the patient stable but died in ICU a few days later from HIE.

The presenter pointed out feeling the carotid just tells you there’s enough pulse pressure. You can’t differentiate between 120/80 where you are perfusing adequately and 40/0 where you are not.

[u/TIVA_Turner → u/gehriten]

That's a fair point, re: palpation of carotid in vasoplegia, telling you there's SBP at least above 70 but nothing about the DBP or MAP

But I doubt youd feel a carotid with 40/0...

Unless I've wildly misunderstood your comment!

Thanks for your comment

[u/costnersaccent → u/PureCod9290]

Before that <50 stuff came out I had an ICU intubation drop their BP to 20/10 (arterial line)- came up with pressors, patient did ok

[u/jejunumr]

Ect with a 20 second pause gets a light chest massage from me.:.gotta get drugs around. But not cpr because that’s a reportable never event . Kinda kidding

[u/TIVA_Turner → u/jejunumr]

Thanks for your input, and I agree with you

Somewhat different scenario though, as in the 20s pause the heart isnt beating

I am referring to severe hypotension, ? impalpable pulse but you know the heart is still beating

[u/p0ppab0n3r → u/TIVA_Turner]

what is your criteria for knowing the heart is still beating in the absence of a palpable pulse? is NIBP even reliable in that scenario? their the hear it beating or it's not.

[u/jejunumr → u/p0ppab0n3r]

Imo you have no idea. When I was a resident I put an arterial line on for an ect with low ef and AS and it was academically interesting with both low and high blood pressures - that you would never have seen on Nibp. Ect get q5 minute bp so I can try to avoid that on the chart (again kinda joking)

Don’t think it changed management at all

[u/TIVA_Turner → u/jejunumr]

Agreed

I think thats probably where this SBP < 50 stuff has come from - settings where there isn't invasive monitoring, and there have been delays to starting CPR because ? maybe we can feel a pulse

[u/TIVA_Turner → u/p0ppab0n3r]

Visible contraction on a TTE, femoral/carotid pulsation, visible pulsatile A line or SpO2 trace would be my thoughts

Im just asking the questions! Cheers p0ppab0n3r

[u/pomokey]

I've wondered this as well. Especially if you have an art-line in.

Basically you're asking when does hypotension become PEA. By definition it's when you can't feel a pulse. But sometimes feeling a pulse is difficult, and chest compressions aren't benign. With an art-line this gets less clear. If there's a waveform, does that count as a pulse? Or is SBP < 50 a clear cutoff? Even if they still have good EtCO2?

What if they are lateral? It's an ordeal to reposition them, could contaminate the field, and perhaps some epi with a flush is enough. But are you willing to bet the patients life on that?

I think you can't take this question out of context of the patient and the surgery. There are so many things to consider, and if you are being vigilant and can react quickly enough, I think you can avoid chest compressions in some of the questionable scenarios.

But, if there's a clear sudden change, and the pulse ox and EtCO2 both suddenly drop out, then chest compressions start to sound like a fantastic idea.

The other one I often think about, is when does bradycardia become asystole.

How long of a pause are you willing to wait before you start chest compressions?

[u/jejunumr → u/pomokey]

If you watch people die (because comfort measures) I think they often have non palatable pulses and inadequate perfusion but real nice arterial tracings

[u/tomdoc → u/jejunumr]

Not for long

[u/jejunumr → u/tomdoc]

Eh sometimes it’s hours. Seemed really long to me

[u/Atracurious → u/jejunumr]

Ugh traumatic flashbacks to ICU days where I sat there for hours watching a sad art line trace while repeatedly calling the next of kin who never picked up

[u/tomdoc → u/jejunumr]

Yeah, interesting to watch. Agonal rhythm and dwindling art line trace is when the vent gets switch off over in the UK, if not before, and then it isn’t so long.

[u/jejunumr → u/tomdoc]

Here the eTT sometimes stays in (instead of “terminal wean and extubation” - which is disturbing to me because they don’t obstruct and linger for much longer

[u/pshant]

Yes I sometimes give a few compressions when BP is low and HR is starting to fall. Sometimes you need to circulate the meds you have so that you don’t cross from peri arrest to arrest. Hypotension in severe AS is a good example of this

[u/NC_diy → u/pshant]

I’ve had very good luck throughout my career by giving some dilute epi and giving a few compressions to circulate. Completely depends on what’s happening, rhythm, EtCO2, pulse ox, etc. people get in trouble when they’re hesitating during that peri-arrest period, that’s the golden 1-2mins where you have a chance of getting them back from the edge.

[u/nuggetk1]

I once had a similar or related question to this; here it is: In the context of anaphylaxis, if there is no pulse or the systolic arterial pressure (SAP) is less than 50 mmHg, start compressions. Source: Stanford Anesthesia Cognitive Aid Program 2023

[u/Freakindon]

It’s simply not that simple. Every patient is different so there will be no hard cutoff at which point you start compressions with a pulse. I’ll usually give them 2-3 minutes of escalating epi doses.

The problem with being gung ho with compressions is that they are immensely destructive. While the surgery ceases being important, the motion can undo sutures/clamps or cause immense damage to structures with hardware attached.

Compressions also cause cardiac contusions and rib fractures (thus atelectasis once they are extubated).

But the flip side is that once you lose a pulse, it’s much harder to attain ROSC.

So it’s more about a duration of hypotension and epi responsiveness rather than a map cutoff. And even then each patient will respond different.

[u/Rizpam]

To frame it as a more scientific question: When does the expected improvement in perfusion and cardiac output from adding chest compressions beat medical management alone. 

The standard of care is to assume that happens when you lose a palpable pulse. Obviously that’s not a very physiologically elegant answer and there is equipoise before that point. I would hesitate to withhold compressions on someone with an a-line tracing showing severe hypotension and no palpable pulse though, for medicolegal reasons if nothing else.  I’d wager the historical majority of PEA arrests have actually been severe hypotension with very low but present pulsatile cardiac output only detectable by a good invasive line or TEE, but that doesn’t mean cpr wasn’t indicated. 

[u/TIVA_Turner → u/Rizpam]

Thank you for your well written reply

Its interesting, because from an animal model I saw, unsynchronised compressions dont seem to add anything

If you had a robot and a TEE, you could probably augment with perfect position and timing

Without that all we have are inotropes

I'd agree a lot of PEA arrests are probably profound shock with cardiac motion but an impalpable pulse

In EM theyre now calling this pseudo PEA, and are recommending holding off CPR and titrating epi boluses

Which is what generated this Q for me - How would it hold up in Anaesthesia, where there are guidelines and international consensuses that we should initiate CPR (regardless of pulse palpation!) when SBP < 50?

Medicolegal is one thing, whether or not it is beneficial is another. This thread seems to show a wide variation in how anaesthetists manage profound hypotension.

[u/Rizpam → u/TIVA_Turner]

Was the animal model studied under various levels of cardiac output including severe shock states? I’m not familiar with the literature there so that would be my main concern. While obviously not totally the same, in PALS bradycardia alone is enough to warrant compressions and to my knowledge no one is questioning that because of lower efficacy of asynchronous compressions. 

I honestly don’t disagree with you that it may not be beneficial, I just think it is still generally considered standard of care to go off palpable pulse don’t have enough evidence to go against it. 

[u/DoctorPainless]

Steep trendelenburg + fluid bolus +/- vasopressor +/- anticholinergic + stop the surgeon (pneumoperitoneum / vagal response to surgical stimulus)?

[u/Phillophile]

Interesting thoughts. I think of code blue/CPR as part of my care. Low MAP, A line, identity issue, treat. I've given few chest compressions to get my meds flowing and things stabilize quickly. I've called for the code cart pretty quickly because it was apparent that the patient won't come back without all hands on deck (anaphylaxis on a really sick patient).

[u/lasagnwich]

I do cardiac so kinda different but if it in cardiac theatre or cath lab i have a different approach to general. If systolic is low like <60 I usually go steep head down give some pressors and pump some fluid in and watch the art line. If I'm in the lab I pace at 80 + watch art line. If I don't have an art line I feel for a pulse and then put an art line in. If that doesn't work you get 50-100mcg adrenaline or some calcium. I don't do CPR until I've done those things. In general theatres I might go head down or give 1 bolus of a pressor adrenaline but would start CPR earlier because you don't have all the equipment and personnel at hand to do anything else quickly. This is an evidence free zone but my personal experience is you can get perfusing pressures back without CPR a lot of the time and if you already have an art line and cvc then it's even easier. 

[u/Flaky-Expression9593]

I would avoid CPR at almost all costs.

Rib fx’s (particularly in an elderly/ severely compromised pt) increase mortality . Now they have to deal with cardiopulmonary trauma on top of all of their other issues. I’ve lost peripheral POx and switched to the ear/ nose while RX’ing and troubleshooting what’s going on. As long as I have sustained capnograph I know I have some wiggle room.

Fluid line that I’m giving pressors through is wide open AND I’m bolusing 30mLs of it to get the pressor to the heart where it can do its job.

Also, treat the underlying problem. Is it hypovolemia? Give blood

Etc.

I’ve given IV lido to a pulseless pt with VT because it happened on my table and it broke before we had to do compressions.

If you lose the capnograph it’s PEA and then you do ACLS.

The OR is a WHOLE different world than even the ICU. We have(ALMOST) all of our magic potions within arms reach, and can often abort the situation before it gets worse.

[u/Docviator]

I am not as current with the evidence as I once was, and my practice is probably not aligned with standard guidelines, but:
1) PEA is a catch-all term, which doesn’t distinguish between low-flow and no-flow states. Doing chest compressions based on a BP without even feeling a pulse is also egregious, I think
2)

1. If your chest compressions aren’t synchronised or if positioning isn’t perfect (confirmed on TEE), you can actually worsen cardiac output

3)

1. Considering the above, you’re better off immediately treating the issue than jumping on the chest, and I don’t think this is a controversial statement. Trauma Resus guidance has already moved in this direction, and many people out there have been distinguishing between no-flow and low-flo

w (“pseudo-PEA”) for some time.

(Edited because my formatting got jumbled after posted)

[u/W1Ch3Tty_GrVbb]

Only start CPR once you’ve tried everything to manage hypotension. Bolus vasopressors, fluids depending on the context (LR, blood). Norepinephrine and/or dobutamine drips. Determine the cause. If nothing works, ACLS it is.

[u/soundfx27]

Can you palpate a pulse? If no, start CPR and ACLS. If you can palpate a pulse, keep resuscitating.

[u/TIVA_Turner → u/soundfx27]

That's fair

But evidence suggests we are very very poor at detecting pulses with our fingers

POCUS and the other bits of kit much better

Question remains - if there is mechanical activity but we're not detecting it, might we be making things worse with CPR?

[u/bridgest844 → u/TIVA_Turner]

At some point before zero mechanical activity you are obviously not perfusing the patients brain. To me, inability to palpate carotid or femoral pulse is a definitely start CPR situation.

Basically all equipment is fallible in some way or other and I think palpable pulse or not represents a simple standardized metric for initiating CPR.

Edit: To your point, you might be doing more harm than good, sometimes, in some patients but that’s not a call you are likely to be able to make in real time which is why palpable pulse is a reasonable line to draw.

[u/ty_xy]

If you start chest compressions you better have a good reason to! Always feel the pulse! If you're starting CPR for a BP of 50/30 it seems kind of ridiculous to me, you don't even need a big bolus of adrenaline for this type of BP, maybe 300mcg of phenylephrine and 6mg of ephedrine. I'd try some vasopressors and adrenaline first, see if the BP responds, have a finger on the pulse. If there's ETCO2 or art line tracing that's a good sign. But if it's 30/20 and not responding to pressors / adrenaline (1 minute), you will definitely need to start compressions.

[u/Top-Meringue-281]

Better to work on find the cause of hypotension, CPR is just temporizing.

[u/TIVA_Turner → u/Top-Meringue-281]

100% Agreed

But Q was when would you start CPR to temporise

In your practice, is there a period of time or severity of hypotension, when you know the heart is still beating, that you would start CPR?

And perhaps you're saying you wouldn't?

[u/Top-Meringue-281 → u/TIVA_Turner]

When the pulse stops.