RSI vs. the "Modified" RSI? What the Hay?

[EM Guy]

When learning airway, I was trained in the 'purist' approach that you don't bag the patient between induction and intubation during RSI b/c of risk of aspiration, etc.
Obviously, this (no extra breaths) can lead to significantly lower sats when the tube is finally in than if the patient had received a few breaths while waiting the the sux/roc/whatever to take effect (the 'modified' RSI). If you can get away with delivering the extra breaths, you get a lot more time before desaturation (filling up FRC more effectively, etc, etc.).
Supposedly there is evidence that delivering these extra few breaths between induction and intubation during RSI with a full stomach does NOT increase the chances of aspiration. (I know that this seems counter-intuitive, but that's why it's important). I've done a search and cannot find those studies, but it would certainly change my practice if true. Anyone heard anything in this vein? I've posted the same in the EMed lounge. Thanks

---

Members don't see this ad.

 

[jetproppilot]

When learning airway, I was trained in the 'purist' approach that you don't bag the patient between induction and intubation during RSI b/c of risk of aspiration, etc.
Obviously, this (no extra breaths) can lead to significantly lower sats when the tube is finally in than if the patient had received a few breaths while waiting the the sux/roc/whatever to take effect (the 'modified' RSI). If you can get away with delivering the extra breaths, you get a lot more time before desaturation (filling up FRC more effectively, etc, etc.).
Supposedly there is evidence that delivering these extra few breaths between induction and intubation during RSI with a full stomach does NOT increase the chances of aspiration. (I know that this seems counter-intuitive, but that's why it's important). I've done a search and cannot find those studies, but it would certainly change my practice if true. Anyone heard anything in this vein? I've posted the same in the EMed lounge. Thanks

Sorry EM, I cant think of any good literature to answer your question. Maybe Mil/UT/Noyac has some input.

What I can tell you is that the utilization of RSI is probably overused, at least in my experience. The chances of aspiration, even if the dude ate at Burger King 2 hours ago is extraordinariliy low if the clinician uses a little reverse Trendelenburg and gentle bags. I moonlighted in an ER pretty frequently for three years during residency and after practicing anesthesia for some time now, it seems in the ER environment that very aggressive bag-mask ventilation is used most of the time which can cause gastric distention quite easily. I think anesthesia personnel, perhaps because they are more comfortable with airway management (not a dis, dude, just that we do it every day over and over) can ventilate with minimal gastric distention on most patients.

That being said, I use true-RSI only in emergency patients that have eaten recently, bowel obstruction type cases, patients with true postural GERD (which is rare), and C sections requiring general anesthesia for whatever reason. Otherwise, the modified-RSI that you mention with a little reverse T-berg works just fine. And I think the Selleck maneuver is overrated.

Doing RSI on all pts with GERD, DM, renal disease, etc etc etc is overkill IMHO.

 

[Idiopathic]

What about RSI for perceived difficult airways? We did a bunch of BMI's >55 yesterday and everyone of them was RSI.

 

[jetproppilot]

What about RSI for perceived difficult airways? We did a bunch of BMI's >55 yesterday and everyone of them was RSI.

Overkill. Again, a little reverse-T, gentle bagging. Especially in that population with non-existent FRC...take a little too long with the tube and their sats drop like a rock.
Certainly the academic answer is RSI, but again, overkill, like alotta stuff we are taught.

 

[Noyac]

I find this one hard to comment on because there are so many variables. Your right about the purist being no breaths with induction. But I rarely do it that way in the OR even if the BMI>30 or more. This is because they are NPO. However, the OR is the place that this (no breaths) is ideal because you have time to preoxygenate (denitrogenate) them for as long as you like. This will by you time that you don't get in the ER as often. So if you are intubating in the ER its frequently for hypoxia and the idea is to get oxygen to the lungs as soon as possible. If you can get the tube in lickity split then go for it. If not, giving some easy breaths will by some time. If you have time to preoxygenate then the purist method is fine in my opinion. The more experience you get with airway management the better able you will be to make these decisions. On that note I have only seen 2 patients throw up on induction and one was in the ER and it was ugly but he did fine even with all that cheeseburger (no lye) in his lungs. Not my intubation for that matter.

 

[militarymd]

I stopped doing RSI >5 years ago. RSI is silly, although I will admit I know of no literature.

Why would mask ventilation cause gastric contents to enter the hypopharynx? If anything, positive pressure would keep gastric contents down. Obviously, if you don't know how to handle a mask...which is true with almost any non-anesthesia providers, and you blow the stomach up like a balloon, then there is a chance that stuff will get expelled when you releasethe positive pressure.

The key is to minimize the time from loss of protective airway reflexes to ETT through the vocal cords. What transpires between the two events is of little consequence.....besides ett do not prevent aspiration...ask any intensivist.

I have personally watched gastric contents enter the airway through a properly inflated cuff while performing a bronchoscopy.

Bottomline, patients aspirate when you have less than ideally trained personnel managing the airway.

The other patients who aspirate (small bowel obstructions, etc.)...the really high risk patients....in those patients...it probably doesn't matter what you do, they are going to aspirate...either before, during, or after you intubate.

 

[Liver_7]

What about RSI for perceived difficult airways? We did a bunch of BMI's >55 yesterday and everyone of them was RSI.

I don't think the answer to a (known or unknown or perceived) difficult airway is to RSI. With a difficult airway you have to think about awake blind / fiberoptic . . .

Try explaining a RSI for a difficult airway on the oral boards.

RSI is for a different beast.