Deep Extubation on Abdominal Cases

[JWebar]

So after reading a lot of the "deep extubation" threads in this forum i've been trying it increasingly on my patients (CA–1 here). Works like a charm. The thing is that in my center abdominal cases are extubated awake by law.

We use mainly Sevo which usually led to a patient coughing and bucking endlessly for an eternity before he actually wakes up... I hate this. Sometimes the attending will just pull the tube out when the pt doesn't stop coughing (but still eyes closed) and they sometime larygospasm (positive pressure does the trick most of the time). Those of you who like to deep extubate have this policy also? Or you do the same in this type of cases (chole lap, gastrectomies, hiatal hernias, etc)? What about appendectomies if you didn't found the need for RSI (no emesis, properly fasted)?

Consider deep extubation as 0.3–0.4 MAC with Narcotics going on (RR 8–12), just enough to prevent the coughing but having a theoretical gag reflex on board.

Thx in advance!

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[Ignatius J]

So after reading a lot of the "deep extubation" threads in this forum i've been trying it increasingly on my patients (CA–1 here). Works like a charm. The thing is that in my center abdominal cases are extubated awake by law.

We use mainly Sevo which usually led to a patient coughing and bucking endlessly for an eternity before he actually wakes up... I hate this. Sometimes the attending will just pull the tube out when the pt doesn't stop coughing (but still eyes closed) and they sometime larygospasm (positive pressure does the trick most of the time). Those of you who like to deep extubate have this policy also? Or you do the same in this type of cases (chole lap, gastrectomies, hiatal hernias, etc)? What about appendectomies if you didn't found the need for RSI (no emesis, properly fasted)?

Consider deep extubation as 0.3–0.4 MAC with Narcotics going on (RR 8–12), just enough to prevent the coughing but having a theoretical gag reflex on board.

Thx in advance!

I can say it's an academic thing to look for hand grip and head lift, etc. A small minority in private practice do that, if any (because I haven't seen any). Pretty much all my extubations are with the patient "not awake". I'm convinced some of a sore throat is having your vocal cords slam against a rigid tube as you're waking up. With experience, you can and should begin to know when you may have cut it close with the relaxant and know when to be more conservative.

One thing I do every now and then on shoulders or hernias or any cases where the surgeon cringes in the corner while the patients buck is extubate deep after titrating narcotics to a RR of 6-10 and slip in an LMA. LMAs are pretty much the best oral airway you an have, IMO. Don't bug the patient at all and just let them spit it out in PACU.

Other things are waiting for 0.5 mac or so and bolusing 0.5mg/kg propofol about 30 seconds before pulling the tube (or 1mg/kg for kids). This works well too for me.

Or you can just pull it well over 1 MAC after suctioning and letting down the cuff to make sure they aren't responding and pull it and assist them until they breathe off some gas and don't obstruct as readily.

It's all just toying with techniques and I always tinker. It's fun to learn to do things different ways.

 

[Mman]

Consider deep extubation as 0.3–0.4 MAC with Narcotics going on (RR 8–12), just enough to prevent the coughing but having a theoretical gag reflex on board.

There is nothing about what you describe here that is a deep extubation.

 

[jwk]

The thing is that in my center abdominal cases are extubated awake by law.

I'm assuming you mean it's your department policy that, as a CA-1, you don't try to violate.

 

[JWebar]

I'm assuming you mean it's your department policy that, as a CA-1, you don't try to violate.

Indeed. I just want to know what others do in such cases.

 

[Mman]

Indeed. I just want to know what others do in such cases.

There are ways to avoid (or at least greatly decrease) coughing and bucking on wake up that don't involve a deep extubation.

 

[deleted171991]

I never do deep extubations (at around 1 MAC). I do almost awake extubations (at around 0.1 MAC). Patient is still asleep, but with most airway reflexes already recovered. Worst case scenario, I catch the end of stage 2 and I need a minute of CPAP and Larson maneuver, but it happens on my watch, and not in the PACU.

I only extubate awake the patients with ET tubes who were (somewhat) difficult to ventilate after induction, or if I need them to be able to protect their airway 100% (upper airway surgical site).

 

[sleepallday]

Pulling the tube at 0.3-0.4 MAC is not a deep extubation. Your probably actually closer to when you should avoid extubation due to increased chances of laryngospasm.

 

[deleted171991]

JWebar, when in doubt about stage 2 at a low MAC, look at the eyes. If diverging, it's still stage 2. If the axes are parallel (after you've seen them diverging), you're safe. That used to be my asleep extubation technique in kids during residency; never a laryngospasm.

On Friday, I was anxious to extubate an adult, even with diverging axes. Bang, laryngospasm.

 

[jwk]

Y'all's definition of deep is different than mine, which is basically the time before I turn everything off. I don't try to lighten up my anesthetic towards the end of the case. I get my patient breathing (reverse, build up CO2), perhaps give some lidocaine IV, and before I turn anything off, pull the tube (in appropriate patients of course). If they buck when I let down the cuff, they're not deep enough, so I'll just let them wake up at that point. I don't see the point in putting them back to sleep to extubate them deep. I'm confident in my mask skills (anyone else still do mask anesthetics?) since I've been doing this since before LMA's were invented, and all I've really done is convert from an anesthetic with an ETT to a mask. Then I wake up the patient. I know my surgeon's well enough that I know how long it takes them to close, and my timing is such that most are awake before they leave the OR, and if they aren't, well, that's why they make PACU's. Many of my patients could probably bypass PACU and go to our phase II recovery, but that would be against our policies. I rarely have my patient's move themselves back to the stretcher except for simple cases like cystos. I have three guys standing there waiting to move the patient, so why not use them? 😉 On the rare instances when I have a laryngospasm, I have a very short trigger for giving a small dose of sux if I can't break it otherwise. It's pointless to struggle for 30-60 seconds trying to break it and steadily increase your risk of NPPE (never had one). Sux works every time.

 

[anes]

Consider deep extubation as 0.3–0.4 MAC with Narcotics going on (RR 8–12), just enough to prevent the coughing but having a theoretical gag reflex on board.

Thx in advance!

What you are doing is more dangerous than either an awake extubation or deep extubation. You're literally timing your extubation for that small window where they will laryngospasm.

Technically, Deep extubation if from the stage of surgical anesthesia. For really reactive airways (young kids) in residency we would crank the sevo to 1.5 mac before extubating.

 

[anes]

JWebar, when in doubt about stage 2 at a low MAC, look at the eyes. If diverging, it's still stage 2. If the axes are parallel (after you've seen them diverging), you're safe. That used to be my asleep extubation technique in kids during residency; never a laryngospasm.

On Friday, I was anxious to extubate an adult, even with diverging axes. Bang, laryngospasm.

I agree partially. The eyes can be center in stage 3 or stage 1. I look at the eyes, then jaw thrust. Sometimes you'll see the eyes divergE.

I've found that 0.3% ET sevo is almost always stage 2. 0.2% ET sevo is safe.

 

[deleted171991]

I agree partially. The eyes can be center in stage 3 or stage 1. I look at the eyes, then jaw thrust. Sometimes you'll see the eyes divergE.

I've found that 0.3% ET sevo is almost always stage 2. 0.2% ET sevo is safe.

That's why I wrote " after you've seen them diverging". At a decreasing low MAC, one doesn't go from stage 2 to stage 3.

 

[Mman]

I've found that 0.3% ET sevo is almost always stage 2. 0.2% ET sevo is safe.

Huh? I've found that patients can oscillate between 0.2% and 0.3% ET sevo for quite some time depending on the case duration and the patient. There is no scenario where 1 reading is absolutely safe and the other is dangerous. It's a continuum. You can't measure their stage of anesthesia when awakening by their ET concentration on the monitor.

 

[JWebar]

A lot of helpful posts here, thanks.

There are ways to avoid (or at least greatly decrease) coughing and bucking on wake up that don't involve a deep extubation.

Care to share? I would really like to know 🙂

JWebar, when in doubt about stage 2 at a low MAC, look at the eyes. If diverging, it's still stage 2. If the axes are parallel (after you've seen them diverging), you're safe. That used to be my asleep extubation technique in kids during residency; never a laryngospasm.

On Friday, I was anxious to extubate an adult, even with diverging axes. Bang, laryngospasm.

I know the theory behind this, but i swear to god that almost every adult case I check the eyes periodically but end up missing stage 2 anyway, so I don't know if it happened already or if its about to. Wait too long and the pt starts bucking -_-

 

[Ignatius J]

There is actually some people out there who preach of stage 2 being more myth than reality in adults. It was first described with ether, and now that we have less soluble gases, people still cling to the stage 2 stuff just as tightly as if the gases aren't much better these days. Is the skepticism warranted? I don't know, but it makes for interesting conversation.

I personally pull quite liberally and acknowledge the increased risk of larygnospasm. I've still never given sux (in an adult) or had a case of NPPE 2/2 larygnospasm.

 

[Mman]

Care to share? I would really like to know 🙂

Aren't your attendings supposed to teach you this sort of stuff? Lidocaine, narcotics, dexmeditomidine, propofol, nitrous, etc.

 

[anes]

Huh? I've found that patients can oscillate between 0.2% and 0.3% ET sevo for quite some time depending on the case duration and the patient. There is no scenario where 1 reading is absolutely safe and the other is dangerous. It's a continuum. You can't measure their stage of anesthesia when awakening by their ET concentration on the monitor.

That's why in my previous post I said that they can have central eyes, and once stimulated they eyes diverg. They vacillate between 0.2 and 0.3. When they're consistently 0.2, it's generally safe to extubate. When they're 0.3 it's almost never safe to extubate. If it's vacillating, it's not safe.

 

[btbam]

A lot of helpful posts here, thanks.



Care to share? I would really like to know 🙂



I know the theory behind this, but i swear to god that almost every adult case I check the eyes periodically but end up missing stage 2 anyway, so I don't know if it happened already or if its about to. Wait too long and the pt starts bucking -_-

If you think adults buck a lot on emergence wait until you do peds.

 

[Mman]

That's why in my previous post I said that they can have central eyes, and once stimulated they eyes diverg. They vacillate between 0.2 and 0.3. When they're consistently 0.2, it's generally safe to extubate. When they're 0.3 it's almost never safe to extubate. If it's vacillating, it's not safe.

If you think 0.2 is safe and 0.3 is safe, there is no rational or scientific basis for that belief. Do you take into account age? I mean 0.2 ET Sevo is way less MAC than it is on a 70 year old. You should base your extubation decision on clinical criteria, not on an ET reading on the vent which can be influenced by lots of things including tidal volume exhaled.

 

[Noyac]

JWebar, when in doubt about stage 2 at a low MAC, look at the eyes. If diverging, it's still stage 2. If the axes are parallel (after you've seen them diverging), you're safe. That used to be my asleep extubation technique in kids during residency; never a laryngospasm.

On Friday, I was anxious to extubate an adult, even with diverging axes. Bang, laryngospasm.

I'm glad you tried it so that I don't have to. I never extubated while divergent and always wondered how true it was, 100% or more like 50/50. Your N of 1 helps. Good job.

 

[Ignatius J]

If you think 0.2 is safe and 0.3 is safe, there is no rational or scientific basis for that belief. Do you take into account age? I mean 0.2 ET Sevo is way less MAC than it is on a 70 year old. You should base your extubation decision on clinical criteria, not on an ET reading on the vent which can be influenced by lots of things including tidal volume exhaled.

Which is why I increasingly think after reflecting and Googling that we should do away with this "stage" stuff and begin teaching what emergence and induction truly are- a process that involves deactivation/activation of brain neurons, both excitatory and inhibitory, in a different temporal manner. If we understand this, we can begin to understand why a perfectly good plane of anesthesia at 1 MAC turns into a vomiting and laryngospasm disaster at surgical incision (seen it and it wasn't pretty), why kids with a sympathetic predominant system are more prone to larygnspasm, and why 0.3 MAC doesn't tell you anything about whether the patient can safely be extubated with a minimal risk of larygnospasm.

 

[deleted162650]

Care to share? I would really like to know 🙂

You essentially have to do 3 things to achieve a smooth emergence/awake extubation:

1) Get rid of all (or nearly all) the volatile i.e. propofol/N2O/dex/etc.

2) Have enough narcotic on board so the pt will tolerate an ETT between their cords (RR of 8-12 usually enough)

3) Don't fuk with the pt (or let anyone else fuk with the pt) i.e. late suctioning, moving them around, bumping into the tube, etc.

There are as many different ways to accomplish the above 3 things as there are anesthesiologists and figuring out your own recipe is part of the fun and personal reward especially as a resident when you first start to get it dialed. Everyone you ask will share their own little secrets, but I guarantee that everyone's recipe somehow encompasses the above 3 things.

 

[anes]

If you think 0.2 is safe and 0.3 is safe, there is no rational or scientific basis for that belief. Do you take into account age? I mean 0.2 ET Sevo is way less MAC than it is on a 70 year old. You should base your extubation decision on clinical criteria, not on an ET reading on the vent which can be influenced by lots of things including tidal volume exhaled.

It's an observation, not a freaking extubation guideline. I never said that an end tidal level was ThE only parameter. Should I rephrase? In the clinical context where all other signs show patient is not stage 2 ish, with ET sevo of 0.2 (consistently) is it usually safe to extubate. If all signs point to not being stage 2 and etcco2 is 0.3 (or bouncing between 0.2 and 0.3) I generally wait to extubate.

Chill out.

 

[Mman]

It's an observation, not a freaking extubation guideline. I never said that an end tidal level was ThE only parameter. Should I rephrase? In the clinical context where all other signs show patient is not stage 2 ish, with ET sevo of 0.2 (consistently) is it usually safe to extubate. If all signs point to not being stage 2 and etcco2 is 0.3 (or bouncing between 0.2 and 0.3) I generally wait to extubate.

Chill out.

No. Pretending the difference between ET Sevo of 0.2 and 0.3 on the monitor means something clinically relevant is silly. Defend the absurdity all you want.

 

[anes]

No. Pretending the difference between ET Sevo of 0.2 and 0.3 on the monitor means something clinically relevant is silly. Defend the absurdity all you want.

Okay buddy. You're super smart. I have been convinced that an observation I've Made is false. Please teach me more. Do you have a blog I can follow you on? Can I be your Facebook friend.

 

[dhb]

I consistently extubate aroud 0.4. I agree with anes: if the patient is steady at 0.2 he won't spasm in fact he'll probably be wide eyed and talking

 

[Mman]

Okay buddy. You're super smart. I have been convinced that an observation I've Made is false. Please teach me more. Do you have a blog I can follow you on? Can I be your Facebook friend.

No thanks stalker

 

[JWebar]

Thx 🙂

I still haven't got an answer about my initial question though:

Do you extubate deep (or before fully awake) in elective abdominal cases (both open and laparoscopic)?

 

[deleted171991]

Thx 🙂

I still haven't got an answer about my initial question though:

Do you extubate deep (or before fully awake) in elective abdominal cases (both open and laparoscopic)?

YES.

 

[Mman]

Thx 🙂

I still haven't got an answer about my initial question though:

Do you extubate deep (or before fully awake) in elective abdominal cases (both open and laparoscopic)?

Deep? Sure if it's the right patient.

"Before fully awake" seems to imply not deep. It's either deep or awake. In between leads to problems that I don't want to deal with.

 

[deleted171991]

"Before fully awake" seems to imply not deep. It's either deep or awake. In between leads to problems that I don't want to deal with.

Because you work in an ACT setting, right? 🙂

 

[Mman]

Because you work in an ACT setting, right? 🙂

No, because I'm a physician and try to minimize the risks of complications for my patients.

 

[deleted171991]

No, because I'm a physician and try to minimize the risks of complications for my patients.

Are you running for political office? 🙂

You didn't answer my question. Do you work solo, or with CRNAs? Because we all try to balance the safety of our patients with their comfort. It's just that one has different tolerance for risk based on one's experience, and especially whether one is immediately available to fix the potential complications (a 15 second-laryngospasm in a well-preoxygenated patient done solo is a much smaller deal than being called to the room after the CRNA has screwed it up for 5 minutes).

That also explains why academic attendings seem more anal about a number of things than their solo (PP) counterparts. (E.g. I can make a number of my former teachers nervous just by telling them about doing a case with LMA and muscle relaxation in morbidly obese - and I am pretty conservative.)

 

[epidural man]

Surgeon and many anesthesiologists are sure against the patient coughing "you're gonna disrupt my suture doc!"

That has seem very strange to me. Is the patient never gonna cough again while sutures are in place? Wouldn't you rather test your sutures right here right now - then tonight in the car right home when he has a tremendous amount of pressure from yacking non-stop for 10 minutes?

I know many of you disagree - but that is why we WANT the patient to cough and buck on wake up after a tonsil - tests the beds. If suction is a little to red - they go back in and cauterize some more. Good luck having a tonsil patient never coughing in the next 10 days.

 

[Mman]

You didn't answer my question. Do you work solo, or with CRNAs?

My assumption was you weren't actually asking a question. I've made hundreds of posts detailing my current practice over the years. I am in an ACT model, but that doesn't change my practice in this particular setting. I don't extubate adults in stage 2 if I can help it. Nor can I envision a scenario where I will choose to in the future in any practice setting. If I'm extubating deep, I extubate deep. If not, I let them wake up and protect their airways.

 

[Colba55o]

Best post so far in this thread that has been hijacked by childish bickering.

Except in cases like neuro, eyes, etc where coughing and bucking can be disastrous, I think the fear of it is overrated. So you look smoother in front of the nurses and surgeons if your patients are completely motionless? You bring out all your patients to PACU with LMAs and oral airways..how cool are you?

I think being able to extubate a patient awake comfortably with minimal fuss is one of the marks of a truly seasoned anesthetist (MD or CRNA) and it's something I hope to master the further along I get in my career. Those of you that brag about doing all your extubations at .4 MAC and never having had a complication are probably just lucky

Surgeon and many anesthesiologists are sure against the patient coughing "you're gonna disrupt my suture doc!"

That has seem very strange to me. Is the patient never gonna cough again while sutures are in place? Wouldn't you rather test your sutures right here right now - then tonight in the car right home when he has a tremendous amount of pressure from yacking non-stop for 10 minutes?

I know many of you disagree - but that is why we WANT the patient to cough and buck on wake up after a tonsil - tests the beds. If suction is a little to red - they go back in and cauterize some more. Good luck having a tonsil patient never coughing in the next 10 days.

 

[Ezekiel2517]

I think being able to extubate a patient awake comfortably with minimal fuss is one of the marks of a truly seasoned anesthetist (MD or CRNA) and it's something I hope to master the further along I get in my career. Those of you that brag about doing all your extubations at .4 MAC and never having had a complication are probably just lucky

Being able to extubate a pt awake comfortably with minimal fuss isn't a mark of a truly seasoned anesthetist . It is a basic skill.
And no they are not just lucky

 

[propadope]

Are you running for political office? 🙂

You didn't answer my question. Do you work solo, or with CRNAs? Because we all try to balance the safety of our patients with their comfort. It's just that one has different tolerance for risk based on one's experience, and especially whether one is immediately available to fix the potential complications (a 15 second-laryngospasm in a well-preoxygenated patient done solo is a much smaller deal than being called to the room after the CRNA has screwed it up for 5 minutes).

That also explains why academic attendings seem more anal about a number of things than their solo (PP) counterparts. (E.g. I can make a number of my former teachers nervous just by telling them about doing a case with LMA and muscle relaxation in morbidly obese - and I am pretty conservative.)

A 15 second laryngospasm can be a big deal if they get negative pressure pulmonary edema... But yes better than a 5 min laryngospasm

 

[dhb]

Those of you that brag about doing all your extubations at .4 MAC and never having had a complication are probably just lucky

Should have known that was it, i'm going to play the lottery.

0.4 gas isn't 0.4 mac, and stage 2 is stage 2, pretty obvious so far. I don't extubate patients in stage 2, i do it right before. The difference with someone who extubates deep at one mac is that they go through stage 2 with me at the head and not in pacu with no one watching.

 

[deleted171991]

My assumption was you weren't actually asking a question. I've made hundreds of posts detailing my current practice over the years. I am in an ACT model, but that doesn't change my practice in this particular setting. I don't extubate adults in stage 2 if I can help it. Nor can I envision a scenario where I will choose to in the future in any practice setting. If I'm extubating deep, I extubate deep. If not, I let them wake up and protect their airways.

I wasn't sure whether your practice was not mixed (solo plus ACT). That's why I was asking (I should have explained that, my bad). I am way more defensive and conservative when I direct others vs when I work solo.

To get back on-topic: I think that our definition of (almost) awake differs a lot. (I don't call a patient awake, unless s/he's following commands - which is not a lot of fun with a tube in one's throat.)

Hence the different approaches. I can extubate an ETT patient in many different ways (from deep 1 MAC, to almost awake, to completely awake) without the patient fighting the tube (all it takes is a touch of propofol or fentanyl), and with rare issues (no NPPE yet, @propadope). It's just a matter of safety vs patient comfort vs attending comfort.

My advice to @JWebar and any other resident: do everything in a way that is safe for the patient and not stressful for your attending. On the other hand, remember: NOW (i.e. while you have a safety net) is the time to get into undesirable situations and learn to fix them. As an attending, it will be much easier to get out of trouble you will have already experienced as a resident. Try working with attendings who work solo a lot; they will let you try many more risky things than the ones who haven't sat through a case for ages, and want only to get out of the room ASAP. Just ask for permission first!

 

[Mman]

Should have known that was it, i'm going to play the lottery.

0.4 gas isn't 0.4 mac, and stage 2 is stage 2, pretty obvious so far. I don't extubate patients in stage 2, i do it right before. The difference with someone who extubates deep at one mac is that they go through stage 2 with me at the head and not in pacu with no one watching.

Extubating patients right before stage 2 isn't deep extubation.

There is also no reason you need to extubate a patient deeply and then have them go through stage 2 with you not around. You can exubate them deeply while they are closing skin and they'll be awake before you roll out of the room. Or you can extubate them when they are putting the dressing on and you can just be with them in PACU as they go through it.

 

[chmd]

Would you want your wife/husband/mother etc extubated deep? It's not difficult to time an awake (opening eyes on command) extubation for when the drapes are coming down. If they buck, a little (30mg ish) propofol is perfect. I work is an act model where I do about 10% of my own cases so maybe I'm missing something, but why add even a slightly increased risk when you don't need to? Also, maybe I'm oblivious but I've never felt pressured to speed turn around if an emergence is poorly timed. Probably because they are rare enough.

I think I'd like to extubated deep (1 MAC) for cervical fusions, but it seems wrong -- even if they were easy masks. Does anyone do that?

 

[Ignatius J]

Should have known that was it, i'm going to play the lottery.

0.4 gas isn't 0.4 mac, and stage 2 is stage 2, pretty obvious so far. I don't extubate patients in stage 2, i do it right before. The difference with someone who extubates deep at one mac is that they go through stage 2 with me at the head and not in pacu with no one watching.

Stage 2 does not exist.

 

[epidural man]

Stage 2 does not exist.

Please elaborate....

 

[Ignatius J]

Please elaborate....

I've touched on it above. And this is just my anecdotal opinion, but something I think explains emergence/induction better. The whole "anesthetic stage theory" started with ether when it took forever and a day to get ether blown off.

Emergence and induction are a continuum as it relates to CNS neurons being blocked. Inhibitory neurons are blocked first and come back last (sort of like peripheral nerve blocks with local anesthetics), leaving relative imbalances of excitatory versus inhibitory impulses at particular times in the anesthetic in the absence of adequate narcotic dosage. You can explain a lot of occurrences through this explanation rather than discreet stages.

Why would a person at 1 MAC w/o paralysis laryngospasm and buck on incision? Did something magically transform him to a different stage? No, I think he was stimulated surgically which resulted in a sympathetic discharge with easily blocked inhibitory neurons still inactivated. As a result, you have an imbalance and hyper excitability.

Why does an adequately narcotized patient never have airway reactivity, irregular breathing patterns, and tachycardia just before emergence? Did they magically transform straight through stage 2? I think they have adequate narcotics on board to blunt sympathetic responses to pain/airway instrumentation and as a result have an ideal balance of excitatory versus inhibitory input and never see a "stage 2". If this were true, I would hypothesize that you could pull the tube at any time and not worry about laryngospasm supposing adequate blunting of sympathetic responses in the face of ongoing blockages of inhibitory neurons. For me, anecdotally, I have seen this to be true.

 

[epidural man]

I'm not disagreeing with you nor agreeing with you.

It's an interesting thought.

However...Stages have also been studied and seemed to have been replicated with the newer agents (in the abscence of polypharmacy).

Sympathetic discharge from surgical stimulis is not the same neurological phenomenon that creates laryngospasm. I think they are two distinct neurological processes and may not be on a continum as you suggest.

 

[epidural man]

Also, I wonder - if sympathetic discharge is the issue - can we treat or even prevent laryngospasm with labetolol?

 

[Arch Guillotti]

Stage 2 does not exist.

Nonsense.

 

[Ignatius J]

Nonsense.

Please explain the neurophysiology behind "stage 2".