Potential for Air Embolism (clinical discussion)

[yoga crna]

I had an interesting case today that made me think about how much information we have to keep in our head and quickly bring up on a moment's notice.

60 year old female in good health having a facelift revision under general anesthesia. The surgeon got into a major bleed in the neck--external jugular was cut and wide open while pouring out blood. He was struggling to get it under control, when out of the blue the patient bucked on the endotracheal tube. All I could think about was the possibility of air embolism. End-tidal carbon dioxide didn't change, EKG was NSR and heart sounds normal. I turned off the nitrous oxide and got the patient deeper with propofol and isoflurane. She woke up fine and was talking and even joking while being discharged.

OK, you students, what would you have done? Remember this is office surgery; we don't have cvp or swans.

YogaCRNA

[nilepoc]

joke mode on

If I heard a millwheel murmur, I would go all pulp fiction on it, and get a huge spinal needle, and go fishing for the RA and aspirate that air right outa there.

Joke mode off

About the only thing I would add to your presentation, is to immediately flood the field with saline, and apply pressure with saline soaked gauze. Depending where you are in the case, you could turn the patient to the right side up lateral position, obtain hemostasis, and arrainge transfer for definitive care. Assuming a real VAE has occured.

Thanks for the question.

[WntrMute2]

Since, I was so recently a student, I thought I'd chime in. How about adding PEEP and PPV(if the patient was spontaneously breathing). This would impede venous return, as long as blood flows out, air won't flow in. Simply lowering the head of the bed below the heart would also accomplish similar results.

[Tenesma]

air embolisms usually don't make you buck - you will see a drastic drop off in ETCO2 however... i suspect light anesthesia might be the cause for the bucking.... and it is very difficult to entrain air through the EJ as it is a compressible/collapsable vessel, and therefore if the patient is breathing spontaneously on the ET tube - the vessel would just collapse with inspiratory effort... and if the patient is on the vent, the continous positive pressure from being on the vent will not lead to negative intrathoracic pressure and therefore no air would be entrained.... i wouldn't worry to much about it :) whole different story if the bleed involved a non-collapsable vessel such as the sagittal sinus or what-not - in that case, nilepoc and wintermute are on the right track....

[loisane]

When I read yoga's post, I thought the bucking might be a manifestation of the gasp reflex. A gasp reflex is listed as a sign of VAE, but not seen very often due to most patients are paralyzed. Sounds like yoga's patient was not paralyzed.

Tensma, even though this was a compressible vessel, isn't the fact that it is above the heart (and the head of the bed was probably elevated some, since it was a face lift), doesn't VAE remain a theoretical possiblity?

Regardless of cause, the prudent action was to increase depth, and turn off nitrous, just in case.

BTW, yoga I want to add my congratulations to you on a great anesthesia career. Thanks for being such a great role model, and cyber-mentor.

loisane crna

[Tenesma]

1) agreed: the gasp reflex is a true phenomenon, however it is very rarely seen under general anesthesia - even in a spontaneously breathing patient...

2) i misspoke: when i wrote compressible, I meant collapsable... a vessel that collapses on itself cannot entrain significant air in a spontaneously ventilating patient (negative intrathoracic pressure)... when you do neck surgery in a patient that is reverse-t-burg or dehydrated take a look at the IJ - and you will see that in a spontaneously breathing patient it will completely collapse on itself...