Hypotension Kills

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JANUARY 4, 2018
Tight BP Management Prevents Organ Dysfunction



In what might be the first study of its kind, a team of French researchers has found that an individualized tight approach to blood pressure management reduces the risk for postoperative organ dysfunction compared with standard hemodynamic management. These results, they noted, have far-reaching implications given how common hemodynamic instability and arterial hypotension are during general anesthesia and surgery, and the ease with which the individualized approach can be applied.

“Over the last few years, there has been a large body of compelling evidence that intraoperative care influences postoperative outcomes, especially in sicker patients,” said Emmanuel Futier, MD, PhD, professor of anesthesiology and critical care medicine at University Hospital of Clermont-Ferrand, in Clermont-Ferrand, France. “Specifically, a significant amount of data have been collected on the relationship between intraoperative fluid management and postoperative outcome, and now there is a strong rationale supporting the individualization of fluid administration based on objective hemodynamic goals during surgery in high-risk patients.”

As Dr. Futier described, intraoperative arterial hypotension is common during surgical general anesthesia, and there is a strong association between hypotension and postoperative organ dysfunction and increased postoperative mortality. Nevertheless, there has not been clear, high-level evidence that treating arterial hypotension improves outcome.

Although several current guidelines—including those from the American College of Cardiology and the American Heart Association—recommend individualized care for surgical patients with associated comorbidities, randomized trials using an individualized approach to arterial blood pressure management in surgical patients are sparse.

To fill this gap, Dr. Futier and his colleagues enrolled 298 adult patients into their trial. All of the participants were at increased risk for postoperative complications due to a preoperative acute kidney injury risk index of class III or higher, indicating a moderate to high risk for postoperative kidney injury. Each patient underwent major surgery under general anesthesia. Patients were enrolled from Dec. 4, 2012 through Aug. 28, 2016, as part of the INPRESS (Intraoperative Norepinephrine to Control Arterial Pressure) study—a multicenter, randomized, parallel-group trial conducted in nine French hospitals.

The trial’s individualized management strategy used a continuous infusion of norepinephrine (10 mcg/mL) to achieve systolic blood pressure (SBP) within 10% of the reference value, which was the patient’s resting SBP. By comparison, the standard management strategy calls for treating SBP that is either less than 80 mm Hg or lower than 40% of the patient’s reference value using intravenous ephedrine administered in 6-mg boluses. In all cases, blood pressure was managed throughout surgery and for another four hours postoperatively. “Anesthesiologists should also remember that the definition of usual patient’s blood pressure does not refer to arterial pressure just before induction of anesthesia,” Dr. Futier pointed out.

Benefits of Individualized Care

The study’s primary outcome was a composite of systemic inflammatory response syndrome and dysfunction of at least one organ system (renal, respiratory, cardiovascular, coagulation and neurologic) by postoperative day 7. Secondary outcomes included durations of ICU and hospital stay, adverse events and 30-day all-cause mortality.

As reported in a recent issue of the Journal of the American Medical Association(JAMA 2017 Sep 27. PMID: 28973220), 292 patients completed the trial (mean age, 70±7 years; 15.1% women) and were included in the modified intention-to-treat analysis. It was found that the primary outcome event occurred in 56 of 147 patients (38.1%) who received individualized treatment, compared with 75 of 145 of those (51.7%) assigned to the standard management strategy (relative risk, 0.73; 95% CI, 0.56-0.94; P=0.02). Furthermore, whereas 68 patients (46.3%) in the individualized treatment group experienced postoperative organ dysfunction by day 30, the adverse event occurred in 92 of their counterparts (63.4%) in the standard management group (adjusted hazard ratio, 0.66; 95% CI, 0.52-0.84; P=0.001).

There were no other significant differences between the groups in severe adverse events or 30-day mortality. “It’s especially important to note that there were no statistically nor clinically relevant differences in intraoperative blood losses, which is a common fear of surgeons when higher blood pressure levels are applied,” Dr. Futier said.

As Dr. Futier told Anesthesiology News, the findings have significant potential to affect clinical practice. “This study is, to the best of our knowledge, the first to demonstrate that a strategy aimed at individualizing arterial blood pressure targets—tailored to the patient’s usual blood pressure—can reduce postoperative organ dysfunction. These findings have clear implications in routine practice, given the high frequency of hemodynamic instability and arterial hypotension during general anesthesia and surgery.

“Furthermore,” he said, “the strategy is very easy to apply and doesn’t require [a] big expenditure for an expensive treatment. You just need to know the usual blood pressure of the patient. This is obviously the case for every patient scheduled to elective surgery, but clearly much more difficult for emergency surgery and/or in ICU patients.”

Despite the strength of the findings, Dr. Futier was quick to note that they may not be applicable to all subsets of patients. “It should be kept in mind that we selected a population of patients at high risk of morbidity. It cannot be ruled out that our results might have been somewhat different if the strategy had been applied to lower-risk patients.” The researchers stressed that the study should be replicated in other patient populations before the individualized strategy can be recommended for widespread use.

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I cant wait to show this to the plastic guys during free flaps
 
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Too many "providers" are sloppy and inattentive to low BP especially after induction and/or the time period before incision. The data is highly suggestive that the longer the hypotension is allowed to persist the worse the outcome.

We are being paid to care for patients in a professional manner. At a minimum, we can support the BP, as needed, to a reasonable level. Hypertension in general is well tolerated vs Hypotension which is clearly associated with increased morbidity/mortality. For all those "providers" out there who sit on the stool each and every day there is no excuse to ignore hypotension. For all the supervisors out there covering midlevels on a routine basis these articles should spur you to make certain hypotension is being treated promptly and not ignored by the midlevel in the room.
 
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Too many "providers" are sloppy and inattentive to low BP especially after induction and/or the time period before incision. The data is highly suggestive that the longer the hypotension is allowed to persist the worse the outcome.

We are being paid to care for patients in a professional manner. At a minimum, we can support the BP, as needed, to a reasonable level. Hypertension in general is well tolerated vs Hypotension which is clearly associated with increased morbidity/mortality. For all those "providers" out there who sit on the stool each and every day there is no excuse to ignore hypotension. For all the supervisors out there covering midlevels on a routine basis these articles should spur you to make certain hypotension is being treated promptly and not ignored by the midlevel in the room.

Thank you for the reminder and evidence here, in the past you’ve posted some anecdotes on supervising that have really given me some pause.

Vigilance is so important in our field, don’t just go hit up breakfast in the physicians lounge after induction before morning breaks people (routinely done at my residency program, since faculty usually didn’t even see the next patient in preop...)
 
Too many "providers" are sloppy and inattentive to low BP especially after induction and/or the time period before incision. The data is highly suggestive that the longer the hypotension is allowed to persist the worse the outcome.

We are being paid to care for patients in a professional manner. At a minimum, we can support the BP, as needed, to a reasonable level. Hypertension in general is well tolerated vs Hypotension which is clearly associated with increased morbidity/mortality. For all those "providers" out there who sit on the stool each and every day there is no excuse to ignore hypotension. For all the supervisors out there covering midlevels on a routine basis these articles should spur you to make certain hypotension is being treated promptly and not ignored by the midlevel in the room.
No doubt. The question though is where should you keep the BP? Pt comes to preop at 140/80, doctors office BP 126/60, in the OR 175/80 pre induction. No BP meds at home. What's your target? Personally I aim for mean above 70 on everyone but the healthy and young.
 
No doubt. The question though is where should you keep the BP? Pt comes to preop at 140/80, doctors office BP 126/60, in the OR 175/80 pre induction. No BP meds at home. What's your target? Personally I aim for mean above 70 on everyone but the healthy and young.

MAP within 20% of baseline. I believe that is what the best evidence supports. If the patient is petrified in preop with a BP of 180/95, especially having skipped an ACE or ARB, I'm willing to use a lower BP from clinic visits as the baseline. Truthfully I use the lowest "recent" BP documented during a period of normal physiology for the patient as the baseline I'm willing to let slide down 20% from.
 
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MAP within 20% of baseline. I believe that is what the best evidence supports. If the patient is petrified in preop with a BP of 180/95, especially having skipped an ACE or ARB, I'm willing to use a lower BP from clinic visits as the baseline. Truthfully I use the lowest "recent" BP documented during a period of normal physiology for the patient as the baseline I'm willing to let slide down 20% from.

Do you have said evidence? I looked for it before but haven't really found the 20% rule. The scenario above is standard for our patients.
 
Do you have said evidence? I looked for it before but haven't really found the 20% rule. The scenario above is standard for our patients.

I'm too lazy to dig it up, but retrospective analyses of intraop data correlated with postop complications. There isn't any great evidence and any great cutoff, but I think it's the best we currently have.
 
No difference in outcomes with MAP greater than 65 or within 20% of baseline. So instead of trying to find a good 'baseline', I just keep MAP > 65, unless elderly or sick. Elderly I keep MAP above their age (65 yr old, MAP >65, 80yoa MAP >80, etc).
 

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No difference in outcomes with MAP greater than 65 or within 20% of baseline. So instead of trying to find a good 'baseline', I just keep MAP > 65, unless elderly or sick. Elderly I keep MAP above their age (65 yr old, MAP >65, 80yoa MAP >80, etc).

I prefer a minimum MAP of 70 in hypertensive patients even at the age of 55-60. This gives me a bit of a cushion because the curve is shifted to the right. At age 65 I move that number to 75.


Optimal perioperative management of arterial blood pressure
 
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I'm lost. The article you posted to start the thread recommends keeping SBP within 10% of starting values.

I'm aware of the article's main point to keep BP high (within 10% of baseline) but the N in this study is rather small to make that conclusion. We would need thousands of patients before such a bold statement could be "proven" with any certainty. Remember the Nitrous Oxide controversy? I'm skeptical of studies that make these bold conclusions with a sample size of 278 patients.

Nitrous oxide and long-term morbidity and mortality in the ENIGMA trial. - PubMed - NCBI

Nitrous Oxide and Serious Long-term Morbidity and Mortality in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II Trial | Anesthesiology | ASA Publications

What we do know is that hypotension is bad and leads to increased morbidity/mortality. If you want to keep the pressure within 10% of baseline (which is likely 20% lower than when you see them in preop holding) then by all means do so.

My goal is to keep the BP above a certain minimum threshold which is higher than a MAP of 60-65; that's too low these days for a lot of our patients. That's my point in posting these articles and references.

One final point is the DURATION of hypotension matters a great deal. Even 5 minutes of a MAP below 60 can lead to poor outcomes. We must remain cognizant of this point and treat hypotension aggressively and quickly. This means cycling the cuff 3-4 times while the MAP remains below 50 is not going to cut it.
 
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Do you have said evidence? I looked for it before but haven't really found the 20% rule. The scenario above is standard for our patients.

we did not find a statistically significant risk-adjusted increase in mortality with intraoperative hypertension with any of our three analytic methods. Despite these limitations, we included the percent change from baseline technique because a decrease in SBP of more than 20 to 30% below baseline is one of the most frequently used definitions of intraoperative hypotension in the literature.9 Bijker et al.9 reviewed 111 definitions of intraoperative hypotension and found that only 50% of the manuscripts actually defined the baseline blood pressure, and in those that did, baseline blood pressure was most frequently based on the blood pressure measurements taken immediately before the induction of anesthesia. A previous publication also stated that a prolonged intraoperative change of 20% from preoperative blood pressure levels was significantly related to complications.3 In our analysis, we also defined the baseline blood pressure as the mean blood pressures in the operating room immediately before the appearance of end-tidal carbon dioxide. The lack of agreement of this technique with the population-based and absolute threshold technique suggests that the percent change from baseline technique is flawed, most likely because it is extremely difficult to define valid, reproducible baseline blood pressure, especially if it is based on blood pressures obtained in the operating room.

Association between Intraoperative Hypotension and Hypertension and 30-day Postoperative Mortality in Noncardiac Surgery | Anesthesiology | ASA Publications
 
But but but spine surgery for private insurance anesthesia is sooo lucrative.

My buddies use code modifier for controller hypotension (they put a line under ultrasound all the time ). 5 units extra for controlled hypotension (always document surgeon requested). 1 extra unit for ultrasound use.

This article may cause my friends to lose potentially $500 for controlled hypotension due to surgeon request. Lol.
 
I'm aware of the article's main point to keep BP high (within 10% of baseline) but the N in this study is rather small to make that conclusion. We would need thousands of patients before such a bold statement could be "proven" with any certainty. Remember the Nitrous Oxide controversy? I'm skeptical of studies that make these bold conclusions with a sample size of 278 patients.

Nitrous oxide and long-term morbidity and mortality in the ENIGMA trial. - PubMed - NCBI

Nitrous Oxide and Serious Long-term Morbidity and Mortality in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II Trial | Anesthesiology | ASA Publications

What we do know is that hypotension is bad and leads to increased morbidity/mortality. If you want to keep the pressure within 10% of baseline (which is likely 20% lower than when you see them in preop holding) then by all means do so.

My goal is to keep the BP above a certain minimum threshold which is higher than a MAP of 60-65; that's too low these days for a lot of our patients. That's my point in posting these articles and references.

One final point is the DURATION of hypotension matters a great deal. Even 5 minutes of a MAP below 60 can lead to poor outcomes. We must remain cognizant of this point and treat hypotension aggressively and quickly. This means cycling the cuff 3-4 times while the MAP remains below 50 is not going to cut it.
Well aware. I do basically the same as you. But you put up an article on here without comment suggesting we keep the BP within 10%. And then your next post starts with "hypotension kills". Hence my confusion. I totally agree that one small study isn't changing my practice.
 
The size of the study doesn't matter. If they were able to find a stat. significant result with a small sample size then it must have been a large effect. On the other hand, one single study would not change my practice, until it's replicated at other centres and in other patient populations.
 
The problem with these studies is there's no logical connection between the physiologic study parameter and the very general endpoint of future organ dysfunction. Until someone postulates a believable mechanism (other than an unknowable butterfly effect) by which mild brief "hypotension" is causing this post-op moribidity, then I just don't care. Any patient that ****s the bed post-op will very likely have been labile and/or hypotensive intra-op, because thats how sick patients behave under anesthesia. How is this to be reconciled with the pharmacologic management of acute or chronic heart failure? Where volume deprivation, relative hypotension, and beta blockade are the mechanisms by which pulmonary congestion is resolved and morbidity and mortality improves. I am a cardiac anesthesiologist and I manage all my non-cardiac and cardiac heart failure patients with an eye toward optimal (low!) filling pressures. My patients pretty much never have AKI, I check on all of them. I hate this outcomes research that looks for any signal in the data and immediately chains them together than assumes causation without any plausible mechanism and in the midst of a million confounders.
 
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The size of the study doesn't matter. If they were able to find a stat. significant result with a small sample size then it must have been a large effect. On the other hand, one single study would not change my practice, until it's replicated at other centres and in other patient populations.

Statistical significance doesn't imply clinical significance. Also, as you know it depends on how the results were defined and whether they did ad hoc or post hoc analysis. There's a lot of garbage being published these days.
 
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The problem with these studies is there's no logical connection between the physiologic study parameter and the very general endpoint of future organ dysfunction. Until someone postulates a believable mechanism (other than an unknowable butterfly effect) by which mild brief "hypotension" is causing this post-op moribidity, then I just don't care. Any patient that ****s the bed post-op will very likely have been labile and/or hypotensive intra-op, because thats how sick patients behave under anesthesia. How is this to be reconciled with the pharmacologic management of acute or chronic heart failure? Where volume deprivation, relative hypotension, and beta blockade are the mechanisms by which pulmonary congestion is resolved and morbidity and mortality improves. I am a cardiac anesthesiologist and I manage all my non-cardiac and cardiac heart failure patients with an eye toward optimal (low!) filling pressures. My patients pretty much never have AKI, I check on all of them. I hate this outcomes research that looks for any signal in the data and immediately chains them together than assumes causation without any plausible mechanism and in the midst of a million confounders.
What are you using as a marker for filling pressure?
 
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The problem with these studies is there's no logical connection between the physiologic study parameter and the very general endpoint of future organ dysfunction. Until someone postulates a believable mechanism (other than an unknowable butterfly effect) by which mild brief "hypotension" is causing this post-op moribidity, then I just don't care. Any patient that ****s the bed post-op will very likely have been labile and/or hypotensive intra-op, because thats how sick patients behave under anesthesia. How is this to be reconciled with the pharmacologic management of acute or chronic heart failure? Where volume deprivation, relative hypotension, and beta blockade are the mechanisms by which pulmonary congestion is resolved and morbidity and mortality improves. I am a cardiac anesthesiologist and I manage all my non-cardiac and cardiac heart failure patients with an eye toward optimal (low!) filling pressures. My patients pretty much never have AKI, I check on all of them. I hate this outcomes research that looks for any signal in the data and immediately chains them together than assumes causation without any plausible mechanism and in the midst of a million confounders.

The point of this thread is to avoid hypotension for any duration over 3 minutes (I would even say 1-2 minutes). How you define clinically significant hypotension is up to you; but, we all agree a MAP of less than 60 is simply too low for high risk patients. Yet, I see untreated hypotension all the time and it really bothers me. No matter how much I stress the importance of treating low BP certain providers seems to ignore it (and me).

As for ignoring hypotension for any length of time I think the data is there that it may (I stress may) result in poor outcomes.
 
The point of this thread is to avoid hypotension for any duration over 3 minutes (I would even say 1-2 minutes). How you define clinically significant hypotension is up to you; but, we all agree a MAP of less than 60 is simply too low for high risk patients. Yet, I see untreated hypotension all the time and it really bothers me. No matter how much I stress the importance of treating low BP certain providers seems to ignore it (and me).

As for ignoring hypotension for any length of time I think the data is there that it may (I stress may) result in poor outcomes.
1-2min? Then you're putting alines in everyone. I cycle the cuff q5min.
This is crazy arguing about a couple of minutes of high or low bp when we harvest organs for transplant that go for much longer periods of warm and cold ischemia...
 
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JANUARY 4, 2018
Tight BP Management Prevents Organ Dysfunction




Benefits of Individualized Care

The study’s primary outcome was a composite of systemic inflammatory response syndrome and dysfunction of at least one organ system (renal, respiratory, cardiovascular, coagulation and neurologic) by postoperative day 7. Secondary outcomes included durations of ICU and hospital stay, adverse events and 30-day all-cause mortality.

As reported in a recent issue of the Journal of the American Medical Association(JAMA 2017 Sep 27. PMID: 28973220), 292 patients completed the trial (mean age, 70±7 years; 15.1% women) and were included in the modified intention-to-treat analysis. It was found that the primary outcome event occurred in 56 of 147 patients (38.1%) who received individualized treatment, compared with 75 of 145 of those (51.7%) assigned to the standard management strategy (relative risk, 0.73; 95% CI, 0.56-0.94; P=0.02). Furthermore, whereas 68 patients (46.3%) in the individualized treatment group experienced postoperative organ dysfunction by day 30, the adverse event occurred in 92 of their counterparts (63.4%) in the standard management group (adjusted hazard ratio, 0.66; 95% CI, 0.52-0.84; P=0.001).

There were no other significant differences between the groups in severe adverse events or 30-day mortality. “It’s especially important to note that there were no statistically nor clinically relevant differences in intraoperative blood losses, which is a common fear of surgeons when higher blood pressure levels are applied,” Dr. Futier said.

As Dr. Futier told Anesthesiology News, the findings have significant potential to affect clinical practice. “This study is, to the best of our knowledge, the first to demonstrate that a strategy aimed at individualizing arterial blood pressure targets—tailored to the patient’s usual blood pressure—can reduce postoperative organ dysfunction. These findings have clear implications in routine practice, given the high frequency of hemodynamic instability and arterial hypotension during general anesthesia and surgery.

“Furthermore,” he said, “the strategy is very easy to apply and doesn’t require [a] big expenditure for an expensive treatment. You just need to know the usual blood pressure of the patient. This is obviously the case for every patient scheduled to elective surgery, but clearly much more difficult for emergency surgery and/or in ICU patients.

“It should be kept in mind that we selected a population of patients at high risk of morbidity. It cannot be ruled out that our results might have been somewhat different if the strategy had been applied to lower-risk patients.” The researchers stressed that the study should be replicated in other patient populations before the individualized strategy can be recommended for widespread use.


According to this study, hypotension actually doesn’t kill despite having a control group that was very permissive of hypotension. There were differences in their primary outcome measures but not in mortality. The authors also acknowledge tight BP management may not be relevant to lower risk populations. And does mild postop organ dysfunction matter long term? If anything the study shows tight BP management doesn’t make a difference in important outcome measures.

The bolded part is especially important to note, not the part about intraoperative blood loss. I don’t know why author chose to emphasize the negative result regarding blood loss instead of the negative result regarding mortality.
 
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1-2min? Then you're putting alines in everyone. I cycle the cuff q5min.
This is crazy arguing about a couple of minutes of high or low bp when we harvest organs for transplant that go for much longer periods of warm and cold ischemia...

Yes, I put in a lot of arterial lines. I also cycle the cuff every 2.5-3 minutes post induction in high risk patients in order to treat hypotension promptly.
 
According to this study, hypotension actually doesn’t kill despite having a control group that was very permissive of hypotension. There were differences in their primary outcome measures but not in mortality. The authors also acknowledge tight BP management may not be relevant to lower risk populations. And does mild postop organ dysfunction matter long term? If anything the study shows tight BP management doesn’t make a difference in important outcome measures.

The bolded part is especially important to note, not the part about intraoperative blood loss. I don’t know why author chose to emphasize the negative result regarding blood loss instead of the negative result regarding mortality.

Severe hypotension does kill patients and the data strongly suggests failure to treat such hypotension is poor care.


Absolute threshold: SBP < 70 mmHg for more than or equal to 5 min (odds ratio, 2.9; 95% CI, 1.7 to 4.9), MAP < 49 mmHg for more than or equal to 5 min (2.4; 1.3 to 4.6), and DBP < 30 mmHg for more than or equal to 5 min (3.2; 1.8 to 5.5). (3) Percent change: MAP decreases to more than 50% from baseline for more than or equal to 5 min

What This Article Tells Us That Is New
  • In a review of more than 18,000 patients undergoing noncar diac surgery within the Veterans Administration Hospital system, application of three definitions of blood pressure deviation based on population and individual patient level data showed that hypotension but not hypertension was associated with increased 30-day mortality

Association between Intraoperative Hypotension and Hypertension and 30-day Postoperative Mortality in Noncardiac Surgery | Anesthesiology | ASA Publications
 
Severe hypotension does kill patients and the data strongly suggests failure to treat such hypotension is poor care.


Absolute threshold: SBP < 70 mmHg for more than or equal to 5 min (odds ratio, 2.9; 95% CI, 1.7 to 4.9), MAP < 49 mmHg for more than or equal to 5 min (2.4; 1.3 to 4.6), and DBP < 30 mmHg for more than or equal to 5 min (3.2; 1.8 to 5.5). (3) Percent change: MAP decreases to more than 50% from baseline for more than or equal to 5 min

What This Article Tells Us That Is New
  • In a review of more than 18,000 patients undergoing noncar diac surgery within the Veterans Administration Hospital system, application of three definitions of blood pressure deviation based on population and individual patient level data showed that hypotension but not hypertension was associated with increased 30-day mortality

Association between Intraoperative Hypotension and Hypertension and 30-day Postoperative Mortality in Noncardiac Surgery | Anesthesiology | ASA Publications


Association does not equal causality. Even the authors acknowledge this.

“Hypotension may be a marker of other direct causes of death (i.e., hemorrhage, sepsis, frailty), and it is unknown whether interventions to improve or maintain blood pressure would improve outcome.”
 
Association does not equal causality. Even the authors acknowledge this.

“Hypotension may be a marker of other direct causes of death (i.e., hemorrhage, sepsis, frailty), and it is unknown whether interventions to improve or maintain blood pressure would improve outcome.”

Good luck with that argument at your deposition. You will need it.
 
Good luck with that argument at your deposition. You will need it.


I treat hypotension because it is conventional wisdom and it makes ME feel better. Whether I’m actually helping the patient is still up in the air.
 
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I treat hypotension because it is conventional wisdom and it makes ME feel better. Whether I’m actually helping the patient is still up in the air.

We know General anesthesia interferes with autoregulation and thus, hypotension may not be tolerated:


Beach Chair Position May Decrease Cerebral Perfusion (just an example of low BP not being tolerated)

Intraoperative Hypotension and Perioperative Ischemic Stroke after General Surgery:A Nested Case-control Study | Anesthesiology | ASA Publications
 
Low Blood Pressure During Surgery Boosts Stroke Risk
  • By KEVIN MCKEEVER




(HealthDay News) -- People face a higher risk of stroke after surgery if they have low blood pressure during their operation, a new report shows.

The finding, to be presented Saturday at the American Society of Anesthesiologists annual meeting in Orlando, Fla., looked at 30,000 patients undergoing surgery in a six-year period. It focused on procedures being done on patients who did not already have conditions with a known risk for post-surgical stroke development.

"While these findings are of clinical importance because blood pressure is a controllable factor, the results should be interpreted with extreme caution due to the small numbers of stroke patients and the complex interaction of patient and surgical factors on the risk of stroke following surgery," Dr. Cor J. Kalkman, of University Medical Center Utrecht, the Netherlands, said in a news release issued by the society. "Especially for sick or elderly patients who may be less tolerant to low blood pressure levels, the results indicate that tight blood pressure control and monitoring may be the next step to prevent excess strokes."

While only 41 patients experienced a stroke within 10 days after surgery, the trend was found even after taking into account factors such as age, gender, history of diabetes, hypertension and previous stroke.
 
We know General anesthesia interferes with autoregulation and thus, hypotension may not be tolerated:


Beach Chair Position May Decrease Cerebral Perfusion (just an example of low BP not being tolerated)

Intraoperative Hypotension and Perioperative Ischemic Stroke after General Surgery:A Nested Case-control Study | Anesthesiology | ASA Publications

They had 42 ischemic strokes out of 48000 cases. 20 of those were carotids. So almost 1 in a thousand. Hypotension was associated with a 1.3% increased risk of stroke so it goes to 1.013 strokes per thousand patients. How many patients do you need to treat to prevent 1 stroke? What are the unintended consequences of putting all those patients on a levophed drip? We all know in the POISE trial that patients died or had strokes in the name of preventing myocardial ischemia. Though that effect is small, just as I suspect the effect of treating hypotension is also small if any. If the effect was large, we wouldn’t still be talking about this.

I’d like to see more evidence before announcing “hypotension kills”.
 
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Hypotension Kills:

Two clinician researchers, Daniel Sessler, MD, and Phillip Devereaux, MD, have led the research that endeavors to find the cause of this deadly phenomenon. Dr. Sessler speculated on the cause in an interview with MDalert.com. “Intraoperative hypotension appears to be the cause,” he said. “When mean arterial pressure [MAP] drops below a threshold of about 66mmHg the rate of MI starts to increase. When MAP reaches 55mmHg for one minute or more the risk of death increases significantly. The longer MAP hypotension is maintained, the higher the risk. This phenomenon is a leading cause of death.”

“Our theory,” Dr. Sessler continued, “is that a supply/demand mismatch is causing the myocardial infarction. An already narrowed artery coupled with operative hypotension seems to be responsible,” he explained.

Dr. Devereaux reiterated this theory that added that “the cause is multifactorial. There is a supply/demand mismatch during surgery. Blood loss and narrowed cardiac vasculature coupled with intraoperative hypotension and other causes are likely at fault,” he explained. General anesthesia (Figure 2) as well as bleeding and drugs administered during surgery can cause drops in MAP.





General%20anesthesia%20cropped.jpg

Figure 2. The administration of inhaled general anesthesia.
“One in 10 of these patients will be dead within 1 month,” noted Dr. Sessler, Chair of the Department of Outcomes Research within the Department of Anesthesiology at Cleveland Clinic in Cleveland Ohio. “If this were a disease, it would be the third leading cause of death in the United States. It is the leading cause of death following surgery.”

This Postop Outcome is the 3rd Leading Cause of Death in the U.S.
 
What It Means: Beware Hypotension

“All these studies suggest that hypotension is likely a bad actor,” Dr. Sessler suggested. “The threshold for injury seems to be an intraoperative mean arterial pressure less than about 65 mm Hg. The worse the hypotension, the worse the outcome.” But Dr. Sessler also cautione d that “there are not currently randomized data showing that preventing hypotension prevents postoperative myocardial injury. We do know that β-blockers, aspirin, clonidine and avoiding nitrous oxide do not safely prevent infarctions. In the meantime, preventing hypotension seems a reasonable strategy for reducing the risk of myocardial injury, which is the leading cause of postoperative death.”

http://www.anesthesiologynews.com/C...s-Third-Leading-Cause-of-Death/36135/ses=ogst
 
The point of this thread is to avoid hypotension for any duration over 3 minutes (I would even say 1-2 minutes). How you define clinically significant hypotension is up to you; but, we all agree a MAP of less than 60 is simply too low for high risk patients. Yet, I see untreated hypotension all the time and it really bothers me. No matter how much I stress the importance of treating low BP certain providers seems to ignore it (and me).

As for ignoring hypotension for any length of time I think the data is there that it may (I stress may) result in poor outcomes.

I’m with you 100% blade. I see significant hypotension ignored pretty much every day in my peds practice. It’s like they’re afraid of Neo, ephedrine, etc. They think I’m crazy for starting pressors, fluid blouses, etc. chasing some arbitrary MAP.
Yes, many of them are healthyish and probably can tolerate pretty significant hypotension, but there’s really no data on what’s safe, where the danger zone is, how it changes with age, etc. There are case reports of watershed infarcts, post op blindness, etc. but no real consensus on where to draw the line. Perhaps there’s some subtle damage done along the way that you’d never see unless you were looking at SPECT scans or pre and post op imaging. It makes me nervous. Maybe some of these concerns about anesthesia and the developing brain really are part of a 2 hit effect with hypotension?
Lots of these kids have many procedures and I look at some of the old anesthetics and I’m amazed.
Of course they all wake up apparently fine, so maybe it’s much ado about nothing.


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Il Destriero
 
Severe hypotension does kill patients and the data strongly suggests failure to treat such hypotension is poor care.


Absolute threshold: SBP < 70 mmHg for more than or equal to 5 min (odds ratio, 2.9; 95% CI, 1.7 to 4.9), MAP < 49 mmHg for more than or equal to 5 min (2.4; 1.3 to 4.6), and DBP < 30 mmHg for more than or equal to 5 min (3.2; 1.8 to 5.5). (3) Percent change: MAP decreases to more than 50% from baseline for more than or equal to 5 min

What This Article Tells Us That Is New
  • In a review of more than 18,000 patients undergoing noncar diac surgery within the Veterans Administration Hospital system, application of three definitions of blood pressure deviation based on population and individual patient level data showed that hypotension but not hypertension was associated with increased 30-day mortality

Association between Intraoperative Hypotension and Hypertension and 30-day Postoperative Mortality in Noncardiac Surgery | Anesthesiology | ASA Publications


This data could also be interpreted to mean that half-dead patients who are circling the drain are more likely to experience intraoperative hypotension when they come to the OR. I’m not suggesting that a SBP in the 60s shouldn’t be treated but any patient who drops that low is sick and has a higher than average expected mortality. It raises more questions than providing any definitive answers about BP management.

Did they experience intraoperative hypotension because they were already closer to death or did the intraoperative hypotension cause the increase in mortality? Will starting an inopressor like epi or norepinephrine to drive the MAP above 60 (70? 80?) modify the outcome? Will a gentle non-overdosing induction on a septic hypotensive dead bowel patient modify his outcome? Should we go back to etomidate? Is it worth giving a little epi or neosynephrine preemptively prior to induction to avoid transient hypotension? (I do this but I don’t know if it makes any difference. It does make me feel better not to see a SBP of 60 or less after induction.) Does a MAP of 55 on a healthy 20yo getting a knee scope need to be treated? What about young exsanguinated trauma patients? We’ve adopted a permissive hypotension strategy with them until surgical hemostasis can be achieved and they do remarkably well with long periods of hypotension (syst<80). We simply don’t know the best strategies in many situations because they haven’t been compared. To make definitive statements about BP management is premature. And the first study posted in this thread showed no difference in mortality between tight and permissive blood pressure management.
 
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I’m with you 100% blade. I see significant hypotension ignored pretty much every day in my peds practice. It’s like they’re afraid of Neo, ephedrine, etc. They think I’m crazy for starting pressors, fluid blouses, etc. chasing some arbitrary MAP.
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Il Destriero

At my program, we almost never never give pressors in peds. I may have given phenyl here or there, never gave ephedrine. We are told to just keep giving more and more fluids. It doesn't make much sense to me, and I feel like I haven't gotten a good reason why. Why do you treat your peds pts with pressors?
 
Good luck with that argument at your deposition. You will need it.
Because of people like you who are ready to make bold statements. Remember that academics need to publish or invent new concept/theories to be relevant on the conference trail.
 
1. Are you all Treating to map or sbp? The original article used sbp. The cuffs aren't perfect. You may have an sbp that is too low but a map that is 65. My understanding is that no cuffs measure the mean and the algorithm spits out an sbp and dbp. What do you all think?

2. Agree with what was said before about preop holding or that 170 systolic right before you induce. Clinic pressures are probably better?

3. The original article has a title that contradicts the findings, as pointed out before. Read it quick but I swear it said no difference in 30 day mortality

4. Norepinephrine was their pressor with ephedrine boluses. How and why was this their choice. As other have previously stated (cardiac anes doc), a more goal directed approach based on filling pressures, some other monitor or what the tee shows is probably best. Pressure better does not necesserily equal perfusion better. ive seen a completely empty lv with low bp then for some reason neo gets pushed and the a line looks better and people are happy.

5. I like the comments about less induction meds or potentially pressors or inotropic support preemptively with induction. I routinely do both and pick and chose based on comorbidities. Seems to work. Admit it's guessing game though because I really don't know what the patient needed without some monitoring in addition to the noninvasive cuff. Downside
Is a little hypertension, typically better tolerated as pointed out before

6. I like the idea of not letting patients be hypotensive but I propose a wireless circular device the size of our magnets that sits on the chest and can achieve better 3d imaging than either phillips or seimens. Additionally I'd like it omniplane, flexing, etc via an controller app installed on my iPhone. Then we can have a better noninvasive goal directed therapy without all the damn cords. Maybe blockchain will solve
This for us and I'll buy a bunch for my new group with all the bitcoins I need to get rid of
 
Good discussion. Treat hypotension aggressively and promptly because it may save a life. That's my expert opinion on this subject. The attitude that brief bouts of hypotension don't matter simply reinforces the notion that most providers simply don't give a crap to get off their stool. Anesthesia providers are being paid to provide professional care to patients. Thus, avoiding and/or treating hypotension quickly should be par for the course.

In my many years of doing this gig I've found that those providers who pay attention and care about the vitals of their patients typically provide superior care.
 
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