Prolonged Hypotension During Surgery

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BLADEMDA

BLADEMDA

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Did you people read the December Anesthesiology News article about BP and postop outcome?
It appears duration of Hypotension has a strong correlation with patient outcome.

Many of us have suspected that relationship before but now there is evidence linking MAP to outcome. Experts have been telling us to maintain MAP above 75 in our most critical patatients and now we need to make sure that is actually happening in the OR.

In my practice, I am placing arterial lines and using non invasive technology to monitor volume status in many more patients. In addition, I am instructing the midlevel providers to keep the BP up and not let it drift down to MAP of 50; 50 is no longer the acceptable "low" for our sick patients. We should be using a mean of 75 for that group.
 
And while Dr. Sessler was hesitant to make any practice recommendations based on the results of observational studies, the data have changed his perspective. "I do find myself looking for triple lows, and I'm a little quicker to intervene for marginally low arterial blood pressures than I used to be. I no longer feel so comfortable with a MAP of 70."


http://www.ncbi.nlm.nih.gov/pubmed/22546967
 
What came first? The chicken or the egg?

Do they die because they are hypotensive, or are they hypotensive because they are going to die soon?

What is needed is a paper where they treat some and not others (in the thousands), then compare the mortality.
 
urge said:
What came first? The chicken or the egg?

Do they die because they are hypotensive, or are they hypotensive because they are going to die soon?

What is needed is a paper where they treat some and not others (in the thousands), then compare the mortality.
Click to expand...

In the meantime it would be foolish to tolerate MAPs below 75/70 on your patients unless there is a specific reason for doing so.

I'm not sure your chicken or the egg analogy would hold much weight in front of a jury of 12 as they just want you to save the chicken.
 
Blade, so let's say you had someone on the sicker side who had a pre-op BP of 130/90. You get into the case and have them on the lowest acceptable amount of anesthetic and their MAP is still 61. Would you start phenylephrine boluses/drip for a goal MAP of >65? >75? I'm just curious if you think it's worth treating and if so to what goal.
 
BLADEMDA said:
In the meantime it would be foolish to tolerate MAPs below 75/70 on your patients unless there is a specific reason for doing so.

I'm not sure your chicken or the egg analogy would hold much weight in front of a jury of 12 as they just want you to save the chicken.
Click to expand...

I think we all know and understand the "Try telling that to a jury" argument. It's always there. It always will be. We get that.

The problem I have is that there still is uncertainty there. IS someone's BP low because of an underlying poor prognosis or is someone getting a poor prognosis because there BP is low?

We can play it safe and say, "Well, just keep it high". That's fine. That doesn't necessarily mean it is evidence-based though. Just chalk it up to something that we do "just because" or "why not do it this way?"

Is it smart to keep the BP high? Yes. But at what costs? Am I going to throw phenylephrine at someone or flood someone's lungs with fluids, all in the name of *possibly* affecting their morbidity and mortality, while also accepting that it may not be doing a bit of good, as intraoperative hypotension could just be a sign of a failing heart that was just that way long before traversing the OR corridors?

Long story short- I think it's a good thought. But we still need to question this angle. And always be careful.
 
ambiturner said:
Blade, so let's say you had someone on the sicker side who had a pre-op BP of 130/90. You get into the case and have them on the lowest acceptable amount of anesthetic and their MAP is still 61. Would you start phenylephrine boluses/drip for a goal MAP of >65? >75? I'm just curious if you think it's worth treating and if so to what goal.
Click to expand...

This reminds me a lot of the thoughts on peri-operative beta blockade before the POISE study was released. A lot of questions need to be answered before it unquestionably becomes the "standard of care".
 
BLADEMDA said:
In addition, I am instructing the midlevel providers to keep the BP up and not let it drift down to MAP of 50; 50 is no longer the acceptable "low" for our sick patients. We should be using a mean of 75 for that group.
Click to expand...

Was 50 ever the "acceptable low" on sick patients?

What was your "acceptable low" for healthy patients? 30?
 
urge said:
Was 50 ever the "acceptable low" on sick patients?

What was your "acceptable low" for healthy patients? 30?
Click to expand...


I've seen more than a few 'attendings" tolerate a MAP of 55 with a BIS reading of 60 in order to avoid starting vasopressors or inotropes.

I'm in the camp of placing an arterial line and maximizing volume status along with C.O. to maintain a MAP greater than 70.

Yes, I'll start the required inotropes to keep that MAP greater than 70 and the BIS under 60.provided I've optimized preload and Ive get a good grasp of CO/EF (thats why I have TEE avail as well as non invasive technology for SVV/CO)
 
Ignatius J said:
This reminds me a lot of the thoughts on peri-operative beta blockade before the POISE study was released. A lot of questions need to be answered before it unquestionably becomes the "standard of care".
Click to expand...

In the meantime you need to decide how low the MAP should be for your patients in the O.R. If you want to stick with a MAP of 55-60 then so be it. Sometimes all you need is to optimize preload while other times C.O. or SVR is the main issue.

The evidence seems to point to a higher MAP for our patients than classically taught in some Residencies.
 
Ok i'll play the devils advocate (surgeon): how do argue with the fact that plenty of patients have gone through surgery (ears, shoulders) with low BP without adverse events.
I have this ENT who wants patients at 70 systolic says he's never had a problem, ortho is a little more reasonable: wants 90 systolic
 
dhb said:
Ok i'll play the devils advocate (surgeon): how do argue with the fact that plenty of patients have gone through surgery (ears, shoulders) with low BP without adverse events.
I have this ENT who wants patients at 70 systolic says he's never had a problem, ortho is a little more reasonable: wants 90 systolic
Click to expand...

Show him the data. I would not allow MAP below 60 on any patient and MAP of at least 70 on ASA3 and 4 patients.

Ortho patients can be older and sicker especially for total joins so I try for MAP of 70-75 on that group.

You don't have a problem until one day there is a problem. This is sort of like foot drop with high tourniquet pressure or prolonged tourniquet use. The incidence is low so you will get away with it 99 percent of the time; but, eventually one patient suffers the complication and your entire approach to why it happened comes under scrutiny.
 
dhb said:
Ok i'll play the devils advocate (surgeon): how do argue with the fact that plenty of patients have gone through surgery (ears, shoulders) with low BP without adverse events.
I have this ENT who wants patients at 70 systolic says he's never had a problem, ortho is a little more reasonable: wants 90 systolic
Click to expand...

Maybe this is my lack of understanding of the anesthesiologist/surgeon relationship, but while they may "want" these things, at what point do you request they stick to practicing surgery while you provide the anesthetic?
 
dhb said:
Ok i'll play the devils advocate (surgeon): how do argue with the fact that plenty of patients have gone through surgery (ears, shoulders) with low BP without adverse events.
I have this ENT who wants patients at 70 systolic says he's never had a problem, ortho is a little more reasonable: wants 90 systolic
Click to expand...


One needs to realize that the sick patients will not do well in general which could lead to a confounding bias for the study saying low BP leads to worse outcomes. ASA IV patients will do worse verses an ASA I patient. Also, ASA IV patients are usually have more extensive surgeries.

I refuse to go below a MAP of 60 on anyone, including the scoliosis cases that take 10-15 hours. You just need one patient to be blind to be screwed for life.

I had one neurosurgeon who wanted a MAP of 50, I refused asking for literature, he started cursing me out. My group got someone else to continue the case.
 
Some general recommendations could be made for spine surgery, where risk of ION is higher, but whether any of these can prevent it remains unknown. The head should be in neutral position relative to the back; head down is discouraged. In patients with poorly controlled hypertension or significant or suspected atherosclerosis, maintaining systemic arterial pressure seems sensible. Where to keep arterial pressure should be weighed against possible surgical needs for deliberate hypotension to decrease blood loss and maintain adequate operative exposure. In cardiac surgery, many factors are involved in arriving at the optimal systemic perfusion pressures during cardiopulmonary bypass. Arterial pressure management is only one component in care of anaesthetized patients, where the focus is on the entire patient and not only the optic nerve. Hypertensive patients treated with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, often together with β-blockers or calcium channel blockers, are commonly encountered. These patients frequently become hypotensive intraoperatively and might require vasopressors.23 Systemic risks of increasing arterial pressure with vasoactive agents or by infusion of i.v. fluids include serious complications of decreased renal, liver, and intestinal perfusion, congestive heart failure, and myocardial ischaemia. They are important considerations in determining the appropriate range for arterial pressure and fluid resuscitation.36


http://bja.oxfordjournals.org/content/103/suppl_1/i31.full.pdf+html
 
Consultants and specialty
society members who agree that deliberate hypotension
may be used in patients without preoperative chronic
hypertension indicate that blood pressure should be maintained
on average within 24% (range, 0–40%) of estimated
baseline mean arterial pressure or with a minimum systolic
blood pressure of 84 mmHg (range, 50–120 mmHg

http://www.apsf.org/newsletters/html/2008/spring/02_solutions_to_povl.htm
 
Mean within 20% of baseline. The older and sicker you are, the less I tolerate the -20% side of it. 80 years old with longstanding HTN and I'm probably keeping it no less than 5-10% below baseline. If the surgeon is worried about increased blood loss, I'll reassure them that the blood bank should have no problem keeping up.

As an absolute number on anything but young and healthy patients I always get nervous with a mean < 65. Why that number? Probably because that tended to be the ICU standard for titrating drips on critically ill patients.
 
BLADEMDA said:
In the meantime you need to decide how low the MAP should be for your patients in the O.R. If you want to stick with a MAP of 55-60 then so be it. Sometimes all you need is to optimize preload while other times C.O. or SVR is the main issue.

The evidence seems to point to a higher MAP for our patients than classically taught in some Residencies.
Click to expand...

I'm not knocking the principle of keeping the MAP preserved as much as possible. I don't think any anesthesiology practitioner would.

I am arguing that it is a very broad stroke that is being painted, and blood pressure control for every patient needs to be approached on a case by case basis.

The evidence that was used initially in the first post can definitely be questioned and scrutinized. It may be right, or it may be misleading. We don't know. As always with medicine, I think we should proceed with caution when evaluating a possible change in the standard of care.

As I mentioned, it was a foregone conclusion that patients have less MIs with perioperative beta blockade until the POISE study showed that you do that in certain populations at the cost of stroking patients out at a higher clip.

I'm all about improving the standard of care, but we just need to be careful.
 
http://www.anesthesia-analgesia.org/content/early/2011/11/10/ANE.0b013e31823aca2b.full.pdf
(19 year old patient develops paraplegia postop!)

It's all about patient safety so we need to be careful about maintaining Blood Pressure.



This patient should serve as a reminder that,
although induced hypotension may be an adjunct to reducing
blood loss and improving surgical visualization, the
cost-benefit ratio should be considered carefully. Despite
once common assertions that induced hypotension in
the range of 50 to 55 mm Hg is well tolerated in normotensive
adults, some individuals may be unpredictably intolerant
of that degree of hypotension even though it may be
well sustained by many others.
 
If you guys are interested, you can read some of observational studies below for further evidence. I can tell you that some people are already working on elucidating whether intraop hypotension and mortality/morbidity is related causally or not.


Monk TG, Saini V, Weldon BC, Sigl JC: Anesthetic management and one-year mortality after noncardiac surgery. Anesth Analg 2005, 100(1):4-10

Bijker JB, van Klei WA, Vergouwe Y, Eleveld DJ, van Wolfswinkel L, Moons KG, Kalkman CJ: Intraoperative hypotension and 1-year mortality after noncardiac surgery. Anesthesiology 2009, 111(6):1217-1226

Aronson S, Stafford-Smith M, Phillips-Bute B, Shaw A, Gaca J, Newman M: Intraoperative systolic blood pressure variability predicts 30-day mortality in aortocoronary bypass surgery patients. Anesthesiology 2010, 113(2):305-312
 
BLADEMDA said:
And while Dr. Sessler was hesitant to make any practice recommendations based on the results of observational studies, the data have changed his perspective. “I do find myself looking for triple lows, and I’m a little quicker to intervene for marginally low arterial blood pressures than I used to be. I no longer feel so comfortable with a MAP of 70.”
Click to expand...

narcusprince said:
Who? Wolf Stapelfeldt Who? Wolf Stapelfeldt out of Where?
Click to expand...

Gosh, I wonder if these data-mining studies coming out of CCF, where AFAIK they put a BIS on everyone, are being sponsored by Aspect. Oh, that's right, they are.

This concept of the "triple low" is really just a "double low" plus another not-as-useful number. Low MAP and low MAC, yeah, we can all agree that this is an unfavorable situation and that something physiologic/surgical is going very wrong. All a low BIS adds to this "double low" is evidence of cerebral hypoperfusion. Which hopefully at a low MAP, you're already aware of.
 
Re: deliberate hypotension, I think the whole discussion needs to be re-framed a little bit. Here's how I approach it:

Surgeons have knives. Knives cause bleeding. Therefore, surgeons cause bleeding, not anesthesiologists.

The seemingly-widespread notion amongst surgeons that anesthesiologists are responsible for bleeding, or that anesthesiologists have primary responsibility for stopping it, is totally ridiculous. It's funny how some surgeons' patients are always "oozy" and "require" FFP while other surgeons' patients undergoing the same procedure are dry as a bone.

I'm down to do what's best for the patient, up to and including a MAP of 60 in an ASA1 undergoing, say, an ESS. You're getting a CPP of probably 50-55, in a low-CMRO2 state, in a higher-than-normal CBF-CMRO2-relationship state.

But systolics of 90 in the ASA3E hip or 70 (WTF?!?!) in an ASA1, no f*cking way. Those kinds of requests should be met with whatever professional version of a flipped bird you prefer.
 
TIVAndy said:
If you guys are interested, you can read some of observational studies below for further evidence. I can tell you that some people are already working on elucidating whether intraop hypotension and mortality/morbidity is related causally or not.


Monk TG, Saini V, Weldon BC, Sigl JC: Anesthetic management and one-year mortality after noncardiac surgery. Anesth Analg 2005, 100(1):4-10

Bijker JB, van Klei WA, Vergouwe Y, Eleveld DJ, van Wolfswinkel L, Moons KG, Kalkman CJ: Intraoperative hypotension and 1-year mortality after noncardiac surgery. Anesthesiology 2009, 111(6):1217-1226

Aronson S, Stafford-Smith M, Phillips-Bute B, Shaw A, Gaca J, Newman M: Intraoperative systolic blood pressure variability predicts 30-day mortality in aortocoronary bypass surgery patients. Anesthesiology 2010, 113(2):305-312
Click to expand...

http://journals.lww.com/anesthesiol...tive_Hypotension_and_1_Year_Mortality.14.aspx


Thanks for the references. My thread was to simply discuss some new data and how it MAY impact your patient care. I've been around long enough to know that any one study does not necessarily mean you should change your daily routine.

But, I believe patients deserve "vigilance" in their anesthesia providers and that means paying close attention to MAP and any degree of hypotension. The decision for allowing any hypotension for any duration of time (beyond 1-2 min) is one for the Attending Anesthesiologist to make.

Based on good data and anecdotal case reports I use a LOW MAP of 60 in healthy patients and 70-75 in ASA3-4 patients. I'd rather "error" a bit on the higher side than permit even one patient to suffer a stroke, blindness, paraplegic event or even die as a result of hypotension. When you do enough cases (like I have) it isn't a matter of IF something happens to a patient but rather WHEN an adverse event happens to a patient. Since it is my responsibility to act on the patient's behalf based upon "best available evidence" I believe maintaining a reasonable MAP of around 70 is the best course of action.
 
Last edited:
Dr. Drummond believes
that the available evidence favors a lower limit of 70
mmHg in the heathy and normotensive adult in the
supine position, rather than the conventional or classic
limit of 50 mmHg. Dr. Drummond commented
that his most recent chapter in Miller has been modified
to reflect this change in interpretation of available
studies. He also emphasized that over 45% of the
population has an incomplete circle of Willis, which
may decrease the autoregulatory capacity.



References (Selected From 294 Publications)
Drummond JC, Head BP, Patel PM.Statins might contribute to postoperative delirium.Anesthesiology. 2010 Aug;113(2):500-1.

Drummond JC, Sturaitis MK. Brain Tissue Oxygenation During Dexmedetomidine Administration in Surgical Patients With Neurovascular Injuries. J Neurosurg Anesthesiol. 2010 Jul 8. [Epub ahead of print]

Drummond JC.Colloid osmotic pressure and the formation of posttraumatic cerebral edema. Anesthesiology. 2010 May;112(5):1079-81. Head BP, Patel HH, Niesman IR, Drummond JC, Roth DM, Patel PM. Inhibition of p75 neurotrophin receptor attenuates isoflurane-mediated neuronal apoptosis in the neonatal central nervous system. Anesthesiology. 2009 Apr;110(4):813-25.

Drummond JC, Dao AV, Roth DM, Cheng CR, Atwater BI, Minokadeh A, Pasco LC, Patel PM. Effect of dexmedetomidine on cerebral blood flow velocity, cerebral metabolic rate, and carbon dioxide response in normal humans. Anesthesiology. 2008 Feb;108(2):225-32.

Feng Z, Davis DP, Sásik R, Patel HH, Drummond JC, Patel PM. Pathway and gene ontology based analysis of gene expression in a rat model of cerebral ischemic tolerance. Brain Res. 2007 Oct 26;1177:103-23.

Inoue S, Davis DP, Drummond JC, Cole DJ, Patel PM. The combination of isoflurane and caspase 8 inhibition results in sustained neuroprotection in rats subject to focal cerebral ischemia. Anesth Analg. 2006 May;102(5):1548-55.

Schubert A, Deogaonkar A, Drummond JC Precordial Doppler probe placement for optimal detection of venous air embolism during craniotomy. Anesth Analg. 2006 May;102(5):1543-7.

Drummond JC, Englander RN, Gallo CJ.Cerebral ischemia as an apparent complication of anterior cervical discectomy in a patient with an incomplete circle of Willis. Anesth Analg. 2006 Mar;102(3):896-9.
 
asaseal.gif





the pilot wheel, perfect circle, shield, stars, clouds, moon, ship, sea and lighthouse. The motto is VIGILANCE. The patient is represented as the ship, sailing the troubled sea with clouds of doubt, waves of terror, yet being guided by the skillful pilot (the [physician] anesthetist) with constant and eternal (stars), vigilance (motto) by his dependable (lighthouse) knowledge of the art of sleep (moon) to a safe and happy outcome of his voyage through the realm of the unknown. The perfect circle denotes unity of a closed group (the Society).
 
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