Clinical Case

[Idiopathic]

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BTW for anyone interested, there is a great article on "triple low" in this months anesthesiology journal. Triple low = Low bis, low mac, low blood pressure. Its clearly associated with an increased 30 day mortality although the reasoning is still not fully understood. Its like an anesthetic stress test on the brain.

http://journals.lww.com/anesthesiol...=2012&issue=06000&article=00014&type=abstract

is it great because its great or is it great because its from your program? 😉

 

[Idiopathic]

Blood transfusions are a separate issue and are usually not a part of the DNR discussion per se. Those consents are usually done by the surgeon. I usually try to touch on the issue with all patients if I think it is likely that I will need to transfuse (low starting Hgb or expected large EBL).

I verbally consent my patients for blood, ensuring that they have "no religious or social objections to blood transfusion" and then quantifying the likelihood that they will get transfused, based on the nature of the cass (low, likely, highly likely)

 

[RxBoy]

is it great because its great or is it great because its from your program? 😉

Not my program. And no I do not own stock in the BIS company.

 

[Idiopathic]

Not my program. And no I do not own stock in the BIS company.

well just keep titrating anesthetics with it and you will in no time!

 

[BLADEMDA]

So the big boys do not answer.
Here was my plan.
Preop
All the labs I needed were the CBC+ BMP and echo results and type and screen. I had a long talk with the family explaining that it is very likely that patient X will not make it through the procedure. Given pt X high risk factors IE pulmonary htn, MR, old CAD w/o a stress test. Also to complicate matters they were DNR/DNI out of the operating room. The patient was not aware of their surroundings the only thing I knew for sure was that hip was hurting. I placed a pre-induction arterial line. Used a gileho continous cardiac output monitor for Cardiac Index monitoring. Also, I placed Zahl pad on the patient so that if any malignant arrythmias occur we can shock it also had the defibrillator in the room( I did not want anyone scrambeling around trying to find it). Also pt was NPO for 12 hours( realizing demented head full stomach)
Induction
I came to a few conclusions no Midazolam and no Propofol. I gave 250 mcgs of Fentanyl in divided doses. Had IV scopalamine in the room if I needed to turn off agent. Had an experianced set of hands in the room. IV fentanyl, a little inhalational agent 2.5% Sevo APL set at 20(for bagging). Defasiculating dose of roc Succ tube. Pt had a little jaw rigidity(MH lights went off in back of head). Tupe slid in like butter. Got another 14 IV. Hemodynamics STABLE throghout induction. I prefer tubes in pulmonary hypertensives because one I think hypoxia, hypercarbia, acidosis can be better controlled with an ET tube than a LMA plus demented head demented stomach. I placed the patient on pressure control ventilation to limit the intrathoracic pressure component contributing to the pulmonary hypertension. So tubes in pt is stable. Sevo at about 1.5% surgeons try closed reduction which was does not work. Now we proceed to open reduction. Surgeons make incision pt hemodynamics rock stable HR starts creeping up into the 90-100's I give 50mcgs of fentanyl HR creeps down. HR starts creeping up 100's and irregular looks like Afib start hitting him with Esmolol 30-40 mgs gets the rate down into the 70's. Have to play this cat and mouse game throughout case. ABG sent throughout case was fine Hgb 10/30 no acidosis present. They start closing the hip pt starts breathing spontaneously give a touch of reversal agent pt taking in tidal volumes of 600-700cc with a rate of 8. Case goes well with occasional pressers tried to avoid Neo but had to use it I move the patient off the OR bed into the transport bed. While their is still some agent on board and extubate on the mobile bed. Pt does fine. Goes to PACU has some ST depressions in PACU. I stated that what can we do if patient does have an interoperative or postop MI nothing other than standard 100% O2 beta blockade, Morphine cannot transfuse secondary to the DNR order. Saw the patient 1 day postop looked like a completely different person actively moving does not remember a thing about the case. I will never forget his smile with the new hip in place. Tough case!

You did nice job. I would just mention Norepinephrine may have been a better choice for hypotension over Phenyephrine here due to the Pulm HTN. I would also have vasopressin available if the patient decompensated during the case.

I would place an arterial line but likely would skip the central line after discussing the high morbidity/mortality of this operation with the family. What exactly is the down side of this 92 year old severely demented patient coding in the OR except the paper work?

I had a similar patient to this survive the operation but die on POD number 1. I spoke with the family including the 71 year old daughter and everyone was sad but relieved. I never realized the burden these family members can be under in these situations.

Again, you did a fine job here. I have a few partners that would NOT place any extra monitors in a patient Such as this one; instead, they elect for an LMA after a gentle Propofol induction (0.5 mg/kg) followed by an LMA with a light dose of Sevo. They run the patient light so stimulus Keeps the ETCO2 from going up.

Overall, your approach was a sound one and intubation is indeed the best approach with Pulmonary Hyertrnsion in a demented patient. I reserve Spinals for fully cooperative patients when they have pulmonary hypertension (this way minimal sedation can be used).

 

[BLADEMDA]

Anaesthesia. 2002 Jan;57(1):9-14.
The effect of phenylephrine and norepinephrine in patients with chronic pulmonary hypertension*.
Kwak YL, Lee CS, Park YH, Hong YW.
Source
Anaesthesia Department, Faculty of Medicine, Yonsei University, Seoul, Korea.
Abstract
In this study the effect of phenylephrine and norepinephrine for the treatment of systemic hypotension were evaluated in patients with chronic pulmonary hypertension. When systemic hypotension (systolic arterial pressure < 100 mmHg) occurred following induction of anaesthesia, either phenylephrine or norepinephrine were infused in a random manner to raise the systolic blood pressure by 30% and 50% above baseline values. Norepinephrine decreased the ratio of pulmonary arterial pressure to systemic blood pressure without a change in cardiac index. However, phenylephrine did not increase arterial blood pressure by more than 30% from baseline in one-third of patients and decreased cardiac index without a significant decrease in ratio of pulmonary arterial pressure to systemic blood pressure. These vasoconstrictors showed different systemic and pulmonary haemodynamic effects in patients with chronic pulmonary hypertension as compared to acute pulmonary hypertension. Norepinephrine was considered to be preferable to phenylephrine for the treatment of hypotension in patients with chronic pulmonary hypertension.

 

[BLADEMDA]

The data on the use of vasopressin in pulmonary hypertension is mixed. It should not be your first choice but if the Norepinephrine fails to get the job done here I would use it next.


Display Settings:AbstractSend to:
Br J Anaesth. 2007 Oct;99(4):552-5. Epub 2007 Jul 27.
Use of vasopressin after Caesarean section in idiopathic pulmonary arterial hypertension.
Price LC, Forrest P, Sodhi V, Adamson DL, Nelson-Piercy C, Lucey M, Howard LS.
Source
Department of Respiratory Medicine and Pulmonary Hypertension Service, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK. [email protected]
Abstract
We report the successful use of vasopressin in the management of hypotension in association with severe right ventricular (RV) failure in two patients with advanced idiopathic pulmonary arterial hypertension. Both patients were pregnant and developed systemic hypotension after delivery by Caesarean section. Placental autotransfusion and possibly oxytocin use were thought to be the major contributing factors in worsening RV function. After the use of vasopressin in both patients, cardiovascular variables improved without untoward effect on RV function, and provided rescue therapy for systemic hypotension in this setting. Vasopressin, a direct vasopressor acting via V1 receptors on the vascular endothelium, has been shown to cause pulmonary vasodilatation experimentally and in animal models of pulmonary hypertension. Its synthetic analogue, terlipressin, has been shown to reduce pulmonary vascular resistance in humans with cirrhosis. Vasopressin may therefore have differential effects on the pulmonary and systemic circulations, allowing systemic pressure to be supported without detrimental effects on the pulmonary circulation.
PMID: 17660458 [PubMed - indexed for MEDLINE] Free full text
Publication Types, MeSH Terms, Substances

LinkOut - more resources

 

[Bertelman]

BTW for anyone interested, there is a great article on "triple low" in this months anesthesiology journal. Triple low = Low bis, low mac, low blood pressure. Its clearly associated with an increased 30 day mortality although the reasoning is still not fully understood. Its like an anesthetic stress test on the brain.

http://journals.lww.com/anesthesiol...=2012&issue=06000&article=00014&type=abstract

I suspect the reasoning will never be fully understood, mostly because I don't believe those three numbers really predict anything, nor do they help an anesthesiologist managing a case. So you have a "triple low". Now what? How do you alter your technique? And if you have a low BP heading into a case, of course you will proceed with a low MAC...one leads to the other.

If you've been doing this for any length of time, you can spot the ones with a higher incidence of mortality with a cursory glance at their chart. You certainly don't need a GD BIS to tell you that.

 

[RxBoy]

I suspect the reasoning will never be fully understood, mostly because I don't believe those three numbers really predict anything, nor do they help an anesthesiologist managing a case.

But why would you have a low BIS then? The paper states any 1 variable is pretty meaningless but combining the variables identifies patients with increased risk for 30 day mortality. Actually quadruples it. The question is, is the triple low state simply predicting pts at risk or itself actually worsens outcomes. Some quotes from the study I found interesting:

"A third potential cause of
low BIS is inadequate brain perfusion, resulting in ischemic
suppression of brain metabolism. Brain hypoperfusion may
especially occur in a fraction of patients who demonstrate
low BIS combined with low MAP. The individual autoreg-
ulatory MAP threshold for critically reduced brain blood
flow remains unknown but surely varies widely among pa-
tients, and it is likely that values that generally are well toler-
ated in healthy individuals are completely inadequate in
some patients. Inadequate cerebral perfusion is perhaps
the most interesting putative cause of low BIS because it is
potentially amenable to hemodynamic intervention, such
as giving vasopressors or fluids to improve MAP and brain
perfusion"

So you have a "triple low". Now what? How do you alter your technique? And if you have a low BP heading into a case, of course you will proceed with a low MAC...one leads to the other.

"However, it is worth considering that components of the
triple low state usually can be controlled with common an-
esthetic interventions. For example, BIS can be increased by
reducing volatile anesthetic administration, andMAP can be
increased by giving vasopressors or fluids. Our time-based
analysis demonstrating a significant association between cu-
mulative duration in the triple low state and increased mor-
tality suggests a target for therapeutic intervention. To the
extent that remaining in a triple low state worsens outcomes,
rather than just predicts bad outcomes, clinician intervention
in response to triple low events might reduce mortality. This
theory is being tested in a randomized trial in which clini-
cians are alerted (or not) to triple low events (clinical trial
NCT00998894). The thresholds for this study are identical
to those in the second, time-based, analysis."

The results of that study will be interesting.

 

[ssmallz]

There have been many studies showing that the BIS numbers are less than accurate. To base any clinical decision on the number it spits out is weak. We all know how much anesthetic we get away w/in old people and I routinely do case like this w/0.5% or less sevo. If I'm really concerned I'll add some N2O to increase the mac and keep the VS stable Like PGG said, I don't worry about recall in demented old people, especially when the mortality goin in is very high

The only time I'll use a BIS is when I'm running a TIVA and it's more for documentation CYA purposes in case one of my pts c/o recall in the future, at least I can say I was doing everything I could.

 

[ssmallz]

What exactly is the down side of this 92 year old severely demented patient coding in the OR except the paper work?

Kinda morbid but really puts our job into prospective 😱

 

[dewer]

goood

 

[fakin' the funk]

Sometimes it is easier to just suspend the DNR, especially when the family may have trouble understanding exactly what happens in the OR. I don't think we should make a blanket policy for all comers though.

I'm glad you beat me to this, Arch.

Instead of a blanket policy for "DNR in suspended in the OR" you have to have a discussion with the patient or representative about which of the many interventions that might be forbidden by DNR/DNI are OK and when, and you have to document it. It's not an easy discussion - it takes time, some bedside negotiating, and some real doctorin'.

There are no guidelines on this topic because it is very much a grey area, and no expert opinions out there other than "have a discussion with patient or decision-maker."

 

[fakin' the funk]

BTW for anyone interested, there is a great article on "triple low" in this months anesthesiology journal. Triple low = Low bis, low mac, low blood pressure. Its clearly associated with an increased 30 day mortality although the reasoning is still not fully understood. Its like an anesthetic stress test on the brain.

I should've published my personal observations that the "double low" of low MAP and low MAC is associated with badness. 😀

And for those people I would certainly hope the EEG is burst-suppressed or flat or else the cerebral metabolism would be worsening any ischemia!

 

[OB1🤙]

Yah, I think this triple low business falls into the category of "like, duh, obviously."

I also think that a 14g piv in someone you're not gonna transfuse is a bit... much, as is a CO monitor, but whatever. Nice management.

I think age at this point is worth half a MAC. So you only need 0.2 MAC more. I should publish that.

 

[fakin' the funk]

But I mentioned 3 separate times why I use in older/sicker populations so I guess I'll have to mention it a 4th time seeing as I keep getting the same comments about "recall".

I use it to avoid overdosing the patient on gas. If I can run 0.3 mac, I'll run 0.3 mac.

You are trying to extricate the use of BIS from the prevention of recall...but you can't.

You state you are using BIS as an endpoint to avoid "overdosing" volatile anesthetic.

But in doing so you are also using it to avoid underdosing volatile anesthetic to a level that would get you an unacceptable-to-you BIS, say, >60, the only risk of which is recall.

Plus, BIS was originally tested and their algorithms created -- like they are for most monitors -- on young and healthy people.

So, to conclude, you are using BIS on a population it wasn't tested on for an indication (titration of anesthetic to not-too-deep-but-not-having-recall) that it has been proven to be no better than or inferior to end-tidal-anesthetic-concentration.

 

[BLADEMDA]

Minerva Anestesiol. 2000 May;66(5):398-402.
Bispectral index and anaesthesia in the elderly.

Renna M, Venturi R.
Source

Department of Anaesthesia, Ealing Hospital, London, UK.

Abstract

BACKGROUND:

Due to pharmacokinetic and pharmacodynamic reasons, the elderly are at particular risk of incurring unwanted side effects of drugs commonly used in anaesthesia. The bispectral index (BIS) is an EEG-derived value that measures the sedative component of the anaesthetic state. The BIS could be useful in guiding titration of anaesthetic drugs in the elderly.
METHODS:

A review of the published data was performed by the authors in order to assess the suitability of BIS technology application to the geriatric population.
RESULTS:

Age-related EEG differences exist in the normal population but they do not affect the BIS. The BIS correlates with depth of sedation independently of age. Senile dementia may be associated with significantly lower BIS values.
CONCLUSIONS:

The BIS is a useful guidance for titration of anaesthetic drugs in the elderly. The presence of senile dementia may be a confounding factor in the interpretation of the BIS values during anaesthesia

 

[BLADEMDA]

Anesth Analg. 2003 May;96(5):1380-5, table of contents.
Low baseline Bispectral Index of the electroencephalogram in patients with dementia.

Renna M, Handy J, Shah A.
Source

Department of Anaesthesia, Ealing Hospital, London, United Kingdom. [email protected]

Abstract

The baseline value of the Bispectral Index (BIS) is 96-99 in the awake state. Patients with Alzheimer's disease or vascular dementia may show an increase in slow wave and a decrease in fast wave activity of the electroencephalogram (EEG). BIS is presumed to decrease with EEG slowing. We hypothesized that the baseline "awake" BIS is lower in dementia than in normal elderly patients. We studied 36 patients with Alzheimer's disease or multiinfarct dementia and 36 control patients aged >75 yr. Both groups were assessed with a Mini-Mental State Test. BIS (version 3.4) was recorded from a frontal derivation using an Aspect A-2000 EEG monitor. Off-line data analysis was also performed with the newer version 4.0 of the BIS algorithm. Fourteen of 36 (38%) dementia patients and 4 of 36 (11%) controls had mean baseline BIS 3.4 <93 (P = 0.006). Eighteen of 36 (50%) dementia patients and 8 of 36 (22%) controls had mean BIS 4.0 <93 (P = 0.026). Mean (95% confidence interval) BIS 3.4 was 92.9 (91-95) in the dementia and 96.1 (95-97) in the control group (P = 0.02). Values with BIS 4.0 were, respectively, 89.1 (86-92) and 94.7 (93-96) (P = 0.002). No significant difference was found in age, sex, activity from the electromyogram, and signal quality index. As expected, the difference in Mini-Mental State Test scores was significant (P < 0.0001). A significant proportion of patients with dementia shows a low baseline BIS. The utility of the BIS monitor in detecting dementia warrants further investigation. IMPLICATIONS: This prospective, controlled, observational study demonstrates that electroencephalogram slowing associated with dementia affects the Bispectral Index of the electroencephalogram. A significant proportion of patients with dementia have a lower than normal "awake" Bispectral Index.

 

[BLADEMDA]

BIS has updated its software to the 4.0 version from the 3.4 version. This version is much better for patients in the ICU and those with pre-existing Neurological disease.

 

[BLADEMDA]

Although questions have been raised regarding BIS use in patients with neurological

disease, recent publications have been supportive. In the ICU setting, BIS correlates

with commonly used sedation scales in neurologically injured patients with and without

sedation.



Time course of induction and maintenance for an 85-year-old female undergoing urgent left hip

percutaneous pinning and fixation under general anesthesia with thiopental (STP) and isoflurane (ISO). Patient

was anticoagulated for chronic atrial fibrillation. STP 25 mg IV given with loss of consciousness, each

subsequent dose was given as BIS began to increase. Thirty seconds smoothing rate produced a similar

hysteresis between clinical effect and BIS display. After intubation, ISO targeted of 0.6% end-tidal, then lateral

positioning. ISO was decreased after positioning to 0.3% and case proceeded. Patient was hemodynamically

stable throughout. Fluids were minimized and patient awoke within 2 minutes of surgical completion.

Update on Bispectral Index monitoring 91


BIS has been found useful in predicting recovery of consciousness from

severe brain injury.



69,70 BIS and other electrophysiologic and clinical variables have

enabled construction and cross-validation of a model relating BIS(max) to the

probability of recovery of consciousness in patients in a coma state due to a severe

brain injury.

 

[proman]

The BIS, when treated as a single-channel frontal EEG has some utility. I've done a lot of circ arrest cases with both full EEG monitoring and the BIS. The BIS definitely tracks the EEG and is able to detect burst suppression and iso-electric EEG. I find it useful in non-circ arrest cases on CPB to monitor depth of anesthesia given by the perfusionist. I also regularly start a propofol gtt during rewarming and use that for sedation after weaning from CPB to the unit. The BIS provides an added piece of information in that scenario. As for volatile anesthesia, I'd rather have end tidal gas monitoring to prevent recall.

 

[BLADEMDA]

Some limitations exist to the use of BIS and it is not useful for

some single agent hypnotic techniques (ketamine, dexmedetomidine, nitrous oxide,

xenon, opioids). BIS technology is moving out of the operating room and into diverse

environments were conscious and deep sedation are provided. Anesthesiologists need

to be actively involved in promoting patient safety and providing guidelines for

procedural sedation for other physicians and qualified providers.


http://www.gruponitro.com.br/profi/conhecimentos_arq/artigos/sedacao/Update%20on%20Bispectral%20Index%20monitoring.pdf

 

[BLADEMDA]

The BIS, when treated as a single-channel frontal EEG has some utility. I've done a lot of circ arrest cases with both full EEG monitoring and the BIS. The BIS definitely tracks the EEG and is able to detect burst suppression and iso-electric EEG. I find it useful in non-circ arrest cases on CPB to monitor depth of anesthesia given by the perfusionist. I also regularly start a propofol gtt during rewarming and use that for sedation after weaning from CPB to the unit. The BIS provides an added piece of information in that scenario. As for volatile anesthesia, I'd rather have end tidal gas monitoring to prevent recall.

An Unbiased Literature search would show the value of BIS vs ET Gas Vapor to be equal in a normal patient population; however, the value of BIS vs ET vapor in patients with pre-existing Neurological disease has not been proven. That Said, RXBoy's technique of using BIS in the case described here seems to be rational based on our current evidence.

I use BIS in about 1-2% of my cases but I do have the technology readily available. Recall in patients with moderate to severe Alzheimer's disease is NEVER an issue clinically even with extremely low dose ET Vapor.

 

[RxBoy]

BIS is just one of those technologies anesthesiologists love to hate. It reminds me of vigileo's, continous ScvO2 monitoring, ect. Even if most studies validate BIS, people will still say "give me a tube, standard monitors and cut the bullsh*t". Its almost as though its "cool" to be dismissive of BIS.

However for the sake of education, I think the current residents should at the bare minimum experiment with BIS. At my satellite hospitals its voodoo witchcraft with the attendings. At my home hospital its the standard of care for almost all major procedures.

Just did 2 transcutanous aortic valve replacements. In order to meet criteria for the study they have to have:
1) Severe Aortic Stenosis
2) Estimated life expectancy less than 1 year.
3) Too sick of a candidate for bypass

They are all in the 80-90s range with the whole CABG/CAD/ESRD/pulm HTN/PVD/multiple valvular anomalies story. If you sneeze on them, they will crash.

I run gas at 0.3-0.2 mac. Their BIS is never above >60. Granted this is a low stimulation procedure (except the cutdown or sometimes direct aortic route requiring a mini sternotomy), but I think many people on this board would be overdosing these patients with volatiles. Especially if they are following age based MAC. There are so many factors that influence MAC such as age/narcotics/drugs/pt disease. BIS is not a perfect tool itself but the combination of BIS and Et are better than either one alone (granted you know each technologies limitations).

 

[RxBoy]

Plus, BIS was originally tested and their algorithms created -- like they are for most monitors -- on young and healthy people.

So, to conclude, you are using BIS on a population it wasn't tested on for an indication (titration of anesthetic to not-too-deep-but-not-having-recall) that it has been proven to be no better than or inferior to end-tidal-anesthetic-concentration.

Br J Anaesth. 2009 Mar;102(3):331-5. Epub 2009 Jan 24.
Advance of age decreases the minimum alveolar concentrations of isoflurane and sevoflurane for maintaining bispectral index below 50.

Matsuura T, Oda Y, Tanaka K, Mori T, Nishikawa K, Asada A.
Source

Department of Anesthesiology, Osaka City University Graduate School of Medicine, 1-5-7 Asahimachi, Abeno-ku, Osaka 545-8586, Japan.

Abstract

BACKGROUND:

We investigated age-related differences in the minimum alveolar concentration (MAC) of isoflurane and sevoflurane for maintaining bispectral index (BIS) below 50 (MAC(BIS50)).
METHODS:

One hundred and twenty young (<or=40 yr), middle-aged (41-69 yr), and elderly (>or=70 yr) patients were randomly allocated to one of the six groups. Anaesthesia was induced with isoflurane or sevoflurane in oxygen. After tracheal intubation, we arbitrarily started maintenance of anaesthesia in each group with end-tidal isoflurane and sevoflurane concentrations of 0.8 and 1.2 vol%, respectively. After 10 min at predetermined end-tidal isoflurane or sevoflurane concentrations, BIS was measured for 1 min. MAC(BIS50) of isoflurane or sevoflurane for each group was determined by up-down methodology.
RESULTS:

MAC(BIS50) of isoflurane in young, middle-aged, and elderly patients was 0.82% end-tidal (95% confidence intervals 0.76-0.88), 0.67% (0.61-0.73), and 0.56% (0.51-0.61), respectively, and that of sevoflurane in young, middle-aged, and elderly patients was 1.28% (1.24-1.32), 0.97% (0.89-1.05), and 0.87% (0.84-0.90), respectively. For both isoflurane and sevoflurane, the MAC(BIS50) was significantly higher (P=0.002 and 0.001, respectively) in young patients and significantly lower (P=0.02 for both) in elderly patients than those in middle-aged patients.
CONCLUSIONS:

Advance in age significantly decreased the concentrations of isoflurane and sevoflurane required to maintain BIS below 50. BIS correctly reflected age-associated decrease of end-tidal concentrations of isoflurane and sevoflurane required for maintaining adequate depth of anaesthesia during resting state.

 

[RxBoy]

Ok im done with this bis business. I promise i wont discuss it further if counter argued. Sorry to the op. For the sake of perserving the ops original discussion, i will stop this monsterous derailment I created. I hope it was at least somewhat entertaining and possibly educational.

 

[ssmallz]

Ok im done with this bis business. I promise i wont discuss it further if counter argued. Sorry to the op. For the sake of perserving the ops original discussion, i will stop this monsterous derailment I created. I hope it was at least somewhat entertaining and possibly educational.

You didn't derail this thread. Your viewpoints were well thought out and definatly welcomed. This thread might have taken a turn toward BIS but it's still clinically relevant and sometimes that's just where things go and thats ok too. We need more clinical debate 👍

 

[Idiopathic]

.

 

[pgg]

Ok im done with this bis business. I promise i wont discuss it further if counter argued. Sorry to the op. For the sake of perserving the ops original discussion, i will stop this monsterous derailment I created. I hope it was at least somewhat entertaining and possibly educational.

Arguing is worthwhile. This place is boring when everyone agrees with everyone.

 

[dhb]

This place is boring when everyone agrees with everyone.

I agree

 

[BLADEMDA]

Ok im done with this bis business. I promise i wont discuss it further if counter argued. Sorry to the op. For the sake of perserving the ops original discussion, i will stop this monsterous derailment I created. I hope it was at least somewhat entertaining and possibly educational.

Once you have done enough of these cases (age greater than 80 with multiple co-morbidities) you realize that just a whiff of vapor is all you need (0.2 MAC) to prevent recall. This means most of your ASA4+ cases can be performed with or without BIS and ET vapor of 0.2/0.3 (ISO) is all you need combined with the patient's vitals.

By using BIS now you are becoming comfortable with this concept of low ET vapor readings yet understanding that in this age group more Vapor isn't required. I have found that even though ENIGMA studies question its safety the use of Nitrous Oxide combined with 0.2 ET Vapor (ISO) allows me to run a very stable anesthetic on the sickest patients. That said, I have curtailed the use of N2O these days because of the legal concern over increased risk of MI so my ET Vapor is now more like 0.3/0.4 (Iso).

So, if you end up working at a hospital with limited BIS monitors don't fret over it. Simply remember that the low dose ET Vapor is more than sufficient to prevent recall in this age group (age greater than 80).

 

[Bertelman]

I agree

Boring!