smooth induction and emergence

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

BlackTalon

Full Member
10+ Year Member
15+ Year Member
Joined
Jul 21, 2008
Messages
170
Reaction score
1
Hey everyone,

I'm a first year Anaesthesia resident in Singapore, with only a month of anaesthesia under my belt, so please bear with my ignorance, but I'm truly interested in your opinions regarding techniques for smooth induction and emergence.

This is how a "typical" GA+ETT induction for an ASA 1 60kg male patient goes over here:
- preoxygenate
- 20mg lidocaine
- 100mcg fentanyl
- 100 - 120mg propofol
- atracurium
- ventilate with "overpressure" of volatile agents, typically desfurane at 10%, for 2-3 minutes waiting for atracurium to work
- intubate

The problem I noticed with this approach is the rollercoaster ride that is the hemodynamics. The propofol tends to cause significant hypotension while we are waiting for the relaxant to work. 20mg lidocaine + 100mcg fent doesn't seem to blunt the laryngeal reflexes much, so the BP+HR goes sky high with during intubation. After that, there is typically a long period of little stimulation where the surgeons are cleaning + draping, etc, and the BP usually falls again. This is generally followed by boluses of phenylephrine to keep BP up. Most of us anticipate the surgical incision, so we dose fentanyl + crank up the gas, but occasionally we underestimate things and the BP goes sky high again.

One attending (who was trained in Canada) uses 200-300mcg fentanyl with ~80mg propofol + 0.9mg/kg roc. He claims that the effects of all the meds peak around 1 minute, which is when he intubates. From my observation, his method results in much less hemodynamic swings, but he is truly the minority here. I'll be truly interested to know what I can do in my own practice to achieve smooth and stable induction.

Just thought I'll start a discussion here where everyone can share their secret tips on smooth inductions / emergence.
 
I give versed and fentanyl in the holding area. For a healthy, young ASA 1 60kg male, it might be Versed 2mg and Fentanyl 100mcg. By the time the patient is on the table, and I am done placing monitors, he's pretty sedated. For induction, I give perhaps 1.5mg/kg of propofol (less than the 2mg/kg i was taught). I wait until he has just loses conciousness and then administer 0.5mg/kg of succinylcholine. I proceed quickly to intubation. At this point he may get a little hypertensive from the laryngoscopy, but usually not much. He usually does not get hypotensive.

The key for me is giving the fentanyl enough time to work such that I don't have to slam in propofol and gas to blunt the airway stimulation from intubation.

For smooth emergence, get him breathing spontaneously ASAP (if allowed by the type of surgery), then extubate deep (if allowed by the patient condition).
 
This is how a "typical" GA+ETT induction for an ASA 1 60kg male patient goes over here:

My take home from this post is I need to move to Singapore for the small healthy patients. 60 kg patient? Man, that's about < 1% of our patients and those are emaciated cancer patients.
 
If you're going to mask ventilate for a couple minutes and wait for a nondepolarizer to work, you don't need very much induction drug at all.

And 200-300 mcg of fentanyl with induction is way more than needed unless there's a sternotomy coming IMO.

For blunting the response to DL, esmolol is a better drug than lidocaine or fentanyl with induction. 20 or 40 mg is a good starting place.

You don't need 1 - 1.3 MAC of volatile while the nurse is prepping. It's OK to use less gas during positioning and prep. If you use less you'll need less phenylephrine and ephedrine.
 
Induction: the standard cocktail I'm used to is fentanyl/lidocaine/propofol/vecuronium (assuming I'm not doing an RSI/awake FOI). Hemodynamic changes are usually transient and reverse themselves very quickly. (DL is of course stimulating, but once the tube is in and nobody is stimulating the patient while they're being prepped, expect the BP to plummet in the other direction). I usually do not pay too much mind to them unless the circumstances require me to do so (ie, craniotomy/craniectomy, open heart, aortic surgery, etc).

Emergence: I love using nitrous oxide for this. It allows you to minimize/turn off volatile gas earlier while keeping the patient calm, and leaves the body almost instantaneously. I use it almost always, unless there is a very strong contraindication. Even in laparoscopic procedures, N2O can be used safely once the belly is exsufflated. In some situations, I use remifentanil to help minimize volatile gas usage and leads to a quicker emergence.
 
My take home from this post is I need to move to Singapore for the small healthy patients. 60 kg patient? Man, that's about < 1% of our patients and those are emaciated cancer patients.
well 60kg is a fine weight for a non obese asian male
 
Avoid fentanyl and increase your MAC for intubation. After the patient is intubated, slowly creep the agent back to .6-.7 MAC until they're draping. It's at that point (a few minutes before incision) that I'll give fentanyl. I typically only use fentanyl in quick outpatient procedures and for rescue analgesia postop.

Alternatively, you can dose them with morphine in the holding area (long equilibration half time) or hydromorphone (as you're using fentanyl now) before intubation. With both these approaches you'll need a higher MAC for intubation but you'll have train track vital signs for the case, otherwise.
 
Keep it simple:
- 20mg lidocaine: put the lido in the propofol: no other use for it
- 100mcg fentanyl: skip until pre-incision
- 100 - 120mg propofol: increase a little
- atracurium: give it just before the propofol so you don't have to hang aroud ventilating for too long
- ventilate with "overpressure" of volatile agents, typically desfurane at 10%, for 2-3 minutes waiting for atracurium to work: total overkill ventilate a minute with O2
- intubate: reasonable
 
My take home from this post is I need to move to Singapore for the small healthy patients. 60 kg patient? Man, that's about < 1% of our patients and those are emaciated cancer patients.

I was thinking the same thing. When I first read the post I thought maybe it was a pediatric question. No cisatracurium in Singapore?

Atracurium almost always caused a noticeable histamine release/rash in the peds patients I ever used it on.
 
Yep! I'm always in awe and amused by the varying responses/practices amongst anaesthetists. 70kg Asian male is pretty common here. I personally fit into that profile. Of course we have a small number of obese patients but at present, they are the exception rather than the norm. I certainly hope it remains that way.

We are pretty limited by what constitutes normal practice in our institution. We have pretty high turnover, and thus the patient doesn't spend much time in the induction room. Guidelines forbid us to give opioids without ETCO2, BP, ECG, and SPO2 monitoring, and most anaesthetists wouldn't go through the trouble of attaching all these monitors in the induction room just to give a couple mg of morphine, before detaching them and moving the patient into the OT.

We do have cisatracurium here, but it is rarely used and has to be specially requested for before the case. 99% of cases are done with roc / atracurium. I rarely see signs of histamine release here... perhaps slight redness at the IV arm. Never seen hives / hypotension after atracurium.
 
We have pretty high turnover, and thus the patient doesn't spend much time in the induction room.
Induction room? Funny. In the US, we induce in the OR, with full ASA monitors on, hence the different plan for induction.
 
I think we had them, too, decades ago. Where I trained, there was an old door that said "induction room".
 
Last edited by a moderator:
Apparently the original workflow when the hospital was built was to induce the pt in the induction room while the op was winding down in the OT, and then transfer the pt once the previous case was done, thus improving turnover. We induce all cases in the OT itself now, though the induction room is still useful place for us to set lines, and do spinals.

People here rarely use nitrous, and I noticed those who do are either obs trained or trained in the US. I think it's a culture thing rather than based on actual evidence against nitrous.

I just did a TIVA case with prop/remi. Rock solid vitals even during and post intubation. I'm just trying to achieve this sort of stability with general induction.
 
Another technique I've seen is to give just enough prop to put the pt under, ventilate with O2 till the atracurium takes effect, then another smaller dose of prop to blunt the laryngeal response to intubation. Better stability, but not optimum.
 
Just for the record, morphine takes a looong time to equilibrate with the CNS...such that monitoring in an induction room having given a dose and then rolling to the OR 10 minutes later would be silly. You're not going to see any respiratory depression for at least 30 minutes and peak effect not for 1+ hr.
 
I think we all understand that, but we are all bound by the rules, silly or not
 
Top