Epidural Test Dose

[drlee]

According to Big Blue, the test dose containing epinephrine for correct epidural placement decreases uterine blood flow briefly. However, in the 1995 ABA ITE Exam question 157, it does not. Any opinions pgg?

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[Planktonmd]

According to Big Blue, the test dose containing epinephrine for correct epidural placement decreases uterine blood flow briefly. However, in the 1995 ABA ITE Exam question 157, it does not. Any opinions pgg?

If it goes intra vascular it is conceivable that it might cause some decrease of uterine blood flow for a minute or two.
How clinically significant is this? Only the person who writes these types of useless questions for the ABA would know the answer, and it usually reflects the way that person felt on a specific day.

 

[pgg]

According to Big Blue, the test dose containing epinephrine for correct epidural placement decreases uterine blood flow briefly. However, in the 1995 ABA ITE Exam question 157, it does not. Any opinions pgg?

What Planktonmd said.

This is an old question that time has turned into a bad question for another reason, too.

In a woman in active labor at term, uterine blood flow is decreased by
(1) alpha-adrenergic agonists
(2) beta-adrenergic agonists
(3) hypocarbia
(4) epidural test dose containing epinephrine

Key says B (1 & 3), but phenylephrine is now widely accepted to be as good as, if not better than, ephedrine in terms of uterine blood flow. The question could be read to imply that the epidural test dose went into the epidural space as it normally does (since an intravascular injection is the exceptional case, I wouldn't assume that the question author meant an intravascular test dose).

Miller acknowledges the controversy regarding an intravascular test dose reducing uterine blood flow but says there's no data that any fetus has ever been harmed by a test dose. A test dose that goes where it's supposed to go certainly doesn't affect uterine blood flow; I think all the texts agree on this. 15 mcg of intravascular epinephrine probably would for a very short period of time, but again as Planktonmd said it's almost surely clinically irrelevant.

 

[coprolalia]

It never ceases to amaze me the seemingly limitless depths of useless, arcane medicoirrelevance than can be plumbed within the quiet interlude of "autopilot" during a smooth ASA1 case by too-intelligent-for-their-own-good, otherwise well-meaning clinicians engaged in full-on mental masturbation.

-copro

 

[coprolalia]

Let me put it another way...

How much epinephrine and norepinephrine is released from the adrenal medulla during an unexpectedly and highly stressful experience in a full-term parturient? Should we put all of these women on alpha and beta-blockers?



(Give me a break!)

-copro

 

[pgg]

a smooth ASA1 case

Hey, she's pregnant, that makes her an ASA 2! That puts her a fingerbreadth away from needing a Swan like that lap chole patient on the last ITE.

Board questions test minutia ... always have.

 

[Hockeyguy]

About a month ago I had my first "positve" test dose. My catheter threaded and blood came back. Flushed it with saline and watched..... no more blood. Gave 3-4cc 1.5% Lido with 5mcg epi. Baseline HR 70-80 about 30-60 secs later HR 180 pt complaining of "feeling nervous, my heart is beating hard". Catheter out one level up great epidural no problems. Leson learned. Now I know what a positive intravascular dose looks like. It is much more dramatic then I thought. Just sharing my experience. Still no wet taps (knock-on-wood)

MC

 

[militarymd]

Let me put it another way...

How much epinephrine and norepinephrine is released from the adrenal medulla during an unexpectedly and highly stressful experience in a full-term parturient? Should we put all of these women on alpha and beta-blockers?



(Give me a break!)

-copro

From all the posts that I've read from you, I want to know what I need to do to make you one of my partners.

 

[Planktonmd]

Hey, she's pregnant, that makes her an ASA 2!

I didn't know that pregnancy makes you automatically ASA 2 !

 

[Planktonmd]

From all the posts that I've read from you, I want to know what I need to do to make you one of my partners.

Give him a lot of money

 

[dhb]

I didn't know that pregnancy makes you automatically ASA 2 !

i've heard it does

 

[Planktonmd]

i've heard it does

Why?
Pregnancy is not a disease, it's a physiological state.
There are people who consider pregnant women ASA 2 but you can argue either way and I am not sure there is a universal agreement on this.
Are you guys being taught that pregnancy is automatically ASA 2?

 

[coprolalia]

Are you guys being taught that pregnancy is automatically ASA 2?

No.

And, thanks for the offer, Mil. If Alabama is in my future, I'll keep you posted...

-copro

 

[urge]

Why?
Pregnancy is not a disease, it's a physiological state.
There are people who consider pregnant women ASA 2 but you can argue either way and I am not sure there is a universal agreement on this.
Are you guys being taught that pregnancy is automatically ASA 2?

Pregnancy is a disease. It is the work of the devil. I make all pregnant ladies ASA2. If they look funny I make them a 3.

 

[pgg]

Why?

Do you make all of your smokers and fatties and hypertensives ASA 2s?

If you're going to put the ASA 2 label on patients with well controlled conditions with no functional limitations (HTN, DM, etc), it makes at least as much sense to categorize a healthy pregnant patient as a 2. I'd argue that the normal physiologic changes of pregnancy have more anesthetic implications than any of the usual batch of 2-level conditions.

I certainly have more concern putting a healthy pregnant woman to sleep for a chole than her hypertensive chubby sister ... and in the end, isn't the whole point of the ASA classification to log some kind of pseudoquantification of your concern to facilitate billing and discussion with other doctors?

Now we're splitting hairs worse than the original board question that started this thread.

 

[coprolalia]

Do you make all of your smokers and fatties and hypertensives ASA 2s?

Yes.

If you're going to put the ASA 2 label on patients with well controlled conditions with no functional limitations (HTN, DM, etc), it makes at least as much sense to categorize a healthy pregnant patient as a 2. I'd argue that the normal physiologic changes of pregnancy have more anesthetic implications than any of the usual batch of 2-level conditions.

What about a completely healthy 23-year-old primagravid patient who is thin and has an easy airway? I just don't see the reason to make them a "2" by default.

I certainly have more concern putting a healthy pregnant woman to sleep for a chole than her hypertensive chubby sister ...

I don't.

...and in the end, isn't the whole point of the ASA classification to log some kind of pseudoquantification of your concern to facilitate billing and discussion with other doctors?

The ASA classification, especially between a "2" and a "3", is woefully inadequate in determining and stratifying perioperative risk. There is such a wide degree of interexaminer variability in labeling these patients that it can strike-up quite heated debates on occassion. I've argued (in my residency program) that there is actually little value in assigning this number. I once even went so far as to propose a modified Karnofsky's performance status, as is used by oncologists, in lieu of this blunt and often confusing tool we now use. But, I was told that I would have to do an extensive study that would take years to amass data and require huge numbers of patients and prolonged outcome in order to validate it. I'm working way too hard day-to-day just trying to get through residency.

Now we're splitting hairs worse than the original board question that started this thread.

Hey, splitting hairs is what makes this forum so great. And, such discussions are ultimately important. This kind of debate is very healthy, and in the end makes us think more and become better clinicians.

Keep it up!

-copro

 

[pgg]

What about a completely healthy 23-year-old primagravid patient who is thin and has an easy airway? I just don't see the reason to make them a "2" by default.

I can't remember the last time I saw one of those ... when discussing weight here, we often go by "Portsmouth Units" or 100 kg increments. If she's thin, it's because she's 16 or a chain smoker.

Joking aside, as for the easy-looking airway, pregnant women have 10x the incidence of unexpected difficult airways - ie finding your yourself in the can't-intubate-can't-ventilate algorithm despite a reassuring-looking airway preop. It's still a low risk, but it's significantly different than the normal population.

The thin pregnant woman still has altered CV and respiratory physiology, a higher aspiration risk, airway changes, etc, and often a bad attitude as well. None of this stuff is "normal" in a pregnant woman, and a patient who's not "normal" gets at least a 2 from me. That said, I think the atmosphere of fear that surrounds a general anesthetic in a pregnant woman is way overblown most of the time. (Maybe experience just hasn't burned me enough yet.)

ASA classification seems to be about as useful as Mallampati classification. While there are better, more precise ways to stratify risk (eg the 11-point airway exam) the simple scale has its place.

 

[urge]

Does everyone here test their epidurals? I don't. The times I have been intravascular there has always been blood on the catheter. No need to test there. I always aspirate for before injecting. I think testing is kind of pointless. What are people's thoughts?

 

[coprolalia]

Does everyone here test their epidurals? I don't. The times I have been intravascular there has always been blood on the catheter. No need to test there. I always aspirate for before injecting. I think testing is kind of pointless. What are people's thoughts?

A better question to ask is this: "Why not test-dose an epidural?" What is the downside? Are you certain that catheter is where you think it is?

I add this, though. If I aspirate and get blood (has happened a few times in the literally hundreds of epidurals I've put in), there's absolutely no need to put a test dose in. You know you're intravascular. Pull back until no more blood. Then test dose and/or reposition, re-stick, and re-thread.

-copro

 

[urge]

A better question to ask is this: "Why not test-dose an epidural?" What is the downside? Are you certain that catheter is where you think it is?

I add this, though. If I aspirate and get blood (has happened a few times in the literally hundreds of epidurals I've put in), there's absolutely no need to put a test dose in. You know you're intravascular. Pull back until no more blood. Then test dose and/or reposition, re-stick, and re-thread.

-copro

Sounds reasonable. However, I have never trusted an epidural I had to rescue. I would rather do a new stick.

 

[pgg]

Does everyone here test their epidurals? I don't. The times I have been intravascular there has always been blood on the catheter. No need to test there. I always aspirate for before injecting. I think testing is kind of pointless. What are people's thoughts?

It's an essentially zero-risk procedure that, if nothing else, helps the block set up a bit faster. I usually administer the test dose (3 mL) and if it's negative, give the other 2 - 2.5 mL from the ampule as she's laying down, and start the PCEA infusion. I almost never need to bolus the ropivacaine or bupivacaine.

Test doses are also for detecting intrathecal placement. Sure, wet taps are usually obvious, but it's possible that a catheter could wind up intrathecal even if the Tuohy isn't. If you aspirate, you'll probably get clear fluid back (or is it saline from your LOR technique?). Better to find out because her ass went numb while you're standing there than after an intrathecal PCEA bolus gives her a high spinal.

Aside from saving 90 seconds, what's the advantage to NOT doing a test dose?

 

[Planktonmd]

Does everyone here test their epidurals? I don't. The times I have been intravascular there has always been blood on the catheter. No need to test there. I always aspirate for before injecting. I think testing is kind of pointless. What are people's thoughts?

I had a few epidural catheters where I could not aspirate blood and they were definitely intravascular.
When the catheter is in a small vein you could aspirate and get no blood because the vein simply collapses with aspiration, like small size IV's.
It is definitely worth it to do a test dose,

 

[Planktonmd]

I can't remember the last time I saw one of those ... when discussing weight here, we often go by "Portsmouth Units" or 100 kg increments. If she's thin, it's because she's 16 or a chain smoker.

Joking aside, as for the easy-looking airway, pregnant women have 10x the incidence of unexpected difficult airways - ie finding your yourself in the can't-intubate-can't-ventilate algorithm despite a reassuring-looking airway preop. It's still a low risk, but it's significantly different than the normal population.

The thin pregnant woman still has altered CV and respiratory physiology, a higher aspiration risk, airway changes, etc, and often a bad attitude as well. None of this stuff is "normal" in a pregnant woman, and a patient who's not "normal" gets at least a 2 from me. That said, I think the atmosphere of fear that surrounds a general anesthetic in a pregnant woman is way overblown most of the time. (Maybe experience just hasn't burned me enough yet.)

ASA classification seems to be about as useful as Mallampati classification. While there are better, more precise ways to stratify risk (eg the 11-point airway exam) the simple scale has its place.

The ASA status is about the existence of underlying conditions that affect the patient's health, or more specifically the patient's functional status.
If a woman is pregnant, this is the condition for which you are administering the anesthetic, in a healthy patient, it is comparable to administering anesthesia to a healthy patient who has appendicitis.
Appendicitis and pregnancy are acute problems that happened in healthy patients and required your intervention.

 

[pgg]

Appendicitis and pregnancy are acute problems that happened in healthy patients and required your intervention.

I see you where you're coming from, but I disagree. A healthy person with appendicitis, a fracture, or butt pus doesn't have a wide range of physiologic changes affecting nearly every organ system.

While the purpose of the anesthetic for an appy is to get the appendix out, the purpose of the anesthetic for a pregnant woman is to deliver the baby, not fix the reduced FRC, delayed gastric emptying, higher incidence of airway difficulty, increased blood volume & cardiac output, etc. All of these things deserve at least as much attention as an otherwise healthy patient's hypertension or tobacco abuse, and they will persist after delivery of the kid (the "purpose" of the anesthetic).

 

[Planktonmd]

I see you where you're coming from, but I disagree. A healthy person with appendicitis, a fracture, or butt pus doesn't have a wide range of physiologic changes affecting nearly every organ system.

While the purpose of the anesthetic for an appy is to get the appendix out, the purpose of the anesthetic for a pregnant woman is to deliver the baby, not fix the reduced FRC, delayed gastric emptying, higher incidence of airway difficulty, increased blood volume & cardiac output, etc. All of these things deserve at least as much attention as an otherwise healthy patient's hypertension or tobacco abuse, and they will persist after delivery of the kid (the "purpose" of the anesthetic).

An Appendicitis could rupture, cause peritonitis, bacteremia, sepsis, and death.
If a previously healthy, ASA 1 patient currently has a ruptured appy and peritonitis he will still be ASA 1.

 

[militarymd]

an Appendicitis Could Rupture, Cause Peritonitis, Bacteremia, Sepsis, And Death.
If A Previously Healthy, Asa 1 Patient Currently Has A Ruptured Appy And Peritonitis He Will Still Be Asa 1.

1e

 

[Planktonmd]

1e

Correct.

 

[militarymd]

Hypertension:

If left untreated....based on the Framingham data....after many years of suffering from it....you will suffer from an early MI or stroke....

If you have hypertension, we label you ASA 2.


Pregnancy:

If left untreated....based on historical data....in 9 months 1 in 4 will die, usually from hemorrhage.

If you are pregnant, what should we label you....ASA 1 or ASA 2?

I don't know about everyone else, but it seems pretty clear to me.

 

[pgg]

An Appendicitis could rupture, cause peritonitis, bacteremia, sepsis, and death.
If a previously healthy, ASA 1 patient currently has a ruptured appy and peritonitis he will still be ASA 1.

Pregnant women, healthy or not, carry a set of physiologic baggage that has anesthetic implications. These changes are chronic and not directly related to the surgical procedure being performed. This is a fundamentally different issue than a (potential) complication of appendicitis.

The added risk is small in your young, healthy, thin woman with a reassuring airway ... but it is not baseline. The physiologic changes of a healthy pregnancy inflict few if any functional limitations, yet still impose additional risk to the delivery of a general anesthetic. That is the very definition of an ASA 2 patient.

 

[Planktonmd]

Pregnant women, healthy or not, carry a set of physiologic baggage that has anesthetic implications. These changes are chronic and not directly related to the surgical procedure being performed. This is a fundamentally different issue than a (potential) complication of appendicitis.

The added risk is small in your young, healthy, thin woman with a reassuring airway ... but it is not baseline. The physiologic changes of a healthy pregnancy inflict few if any functional limitations, yet still impose additional risk to the delivery of a general anesthetic. That is the very definition of an ASA 2 patient.

Pregnancy is not "Chronic" , and I disagree with the idea that the physiologic changes in pregnancy are not related to the surgical procedure (delivery of a baby).
Pregnancy is a physiologic state that starts at conception and ends at birth. Anesthesia is needed for the delivery which is the direct result of pregnancy.
The ASA classification is not intended to address transient changes in health it is designed to give an estimate of the underlying functional status of a patient.
The ASA classification is not perfect and pregnancy is one of these situations where it doesn't work well.

 

[Bertelman]

Pregnancy is not "Chronic"

Per Stedman's, the US Natl Center for Health Statistics states a chronic condition as lasting 3 months or longer.

 

[pgg]

Pregnancy is not "Chronic" , and I disagree with the idea that the physiologic changes in pregnancy are not related to the surgical procedure (delivery of a baby).
Pregnancy is a physiologic state that starts at conception and ends at birth.

While we're splitting hairs , chronic is defined as greater than three months, so the physiologic changes associated with a term pregnancy qualify. Furthermore, the physiologic state does not end at birth. The changes begin months before delivery and some persist for days to weeks afterward.

The ASA classification is not perfect and pregnancy is one of these situations where it doesn't work well.

True enough.

 

[urge]

An Appendicitis could rupture, cause peritonitis, bacteremia, sepsis, and death.
If a previously healthy, ASA 1 patient currently has a ruptured appy and peritonitis he will still be ASA 1.

That would be a 3 or 4e to me.

Let's say you have an olympic athlete come to you in shock due to a GSW. He was heathy one hr ago but not now. That would be a 5e to me. I see the ASA as a measure of how sick they are when they come to me. I don't care what the cause of the problem is.

 

[Consigliere]

Joking aside, as for the easy-looking airway, pregnant women have 10x the incidence of unexpected difficult airways - ie finding your yourself in the can't-intubate-can't-ventilate algorithm despite a reassuring-looking airway preop. It's still a low risk, but it's significantly different than the normal population.

I wholeheartedly disagree. I know this dogma is what they teach you in residency. Please provide your (any) source to back up your claim.

 

[core0]

I know from the surgical side it increases the pucker factor. Of course there is still the consult:
"PT has fatty liver disease of pregnancy. We need you to do a liver transplant so that we can deliver the baby."

It was worth having to write up the consult to see coffee spew out of the fellow's nose.

I found this interesting:
http://www.paeaonline.org/0500docs/Webpaper051800.pdf
revisiting the P factor about 1/2 way down. I actually learned a lot about the ASA system from this.

Of course my favorite from the ASA website:
"These definitions appear in each annual edition of the ASA Relative Value Guide. There is no additional information that will help you further define these categories. "

David Carpenter, PA-C

 

[pgg]

I wholeheartedly disagree. I know this dogma is what they teach you in residency. Please provide your (any) source to back up your claim.

I'll work on that ...

To be honest, I can't remember if this is something I was told or something I read.

 

[Planktonmd]

That would be a 3 or 4e to me.

Let's say you have an olympic athlete come to you in shock due to a GSW. He was heathy one hr ago but not now. That would be a 5e to me. I see the ASA as a measure of how sick they are when they come to me. I don't care what the cause of the problem is.

That's not what the classification was intended for.