Toward the end of my second TKA of the day the surgeon gives me a heads up:

"John, so for this next knee, the woman is severely mentally retarded. I did her other knee in June, they placed an LMA, she aspirated and ended up on a vent in the ICU for a week."

After a slow wake up (too much narc as usual), I meet up my MDA in the hall on my way to see the patient. "She's terrified. We'll do a mask induction in the room. She's 40 years old, a little over weight, but no other co-morbidities.

The woman cries and screams all the way to OR. Bong-hit induction goes off without a hitch. We start an IV. I lean over the stretcher and attempt DL. She has a huge tongue, but I have a decent view. Right as I'm about to pass the tube her cords slam shut, largospasm. We quickly break it with some prop and positive pressure. I take another look and the MDA hands me a #6 ETT which I place with no problems. Lung sounds are distant, but everything looks OK.

The MDA then performs a FNB under ultrasound. I work in 100mcg of fent before incision. Things are looking good. I'm running her on 70% N20 with around 1.6 sevo. I'm not giving any paralytic, so I figure that I'll run her deep for a bit and then get her back breathing toward the end.

About 15 mins in her HR jumps up from 65 to 95. I assume they are just stimulating an area not covered by the block - so I give 50 of fent. She settles back down. I didn't notice any chances in her ventilation.

30mins later HR jumps up again. This time I notice my Peak insp pressure has jumped from 29 to 40. I give another 50mcg of fent and put her on manual ventilation. Did my tube move, is she trying to breath? There's no sign of any resp effort, breath sounds are distant but defiantly bilateral. Surgical stimulation dies down (and or my fent kicks in) and my peak pressures fall back to around 28 and her HR dips back into the 60s.

I place a call to the MDA, "The patient is OK, but I have some questions about how I'm ventilating her, do you mind swinging by?"

20mins later - No MDA, but same thing happens again, HR up (but only to the 80s) peak pressures hitting 40. I'm not moving good volumes on manual. She's super hard to ventilate. Sats are dropping (100% to 89%), I'm in trouble. N20 off, 100% O2, flows up. I'm only moving 200ml with a pressure of 40. I decide to deepen her. 50mg of prop and hyperventilation with 5% sevo at high flows. Things improve.

End of the case. MDA finally wanders in. I tell him what happens. "Probably just breath holding, you handled it find."

Pt is slow to wakeup (I've given 250mcg of fent). I've had her spont breathing for the last 20 mins or so of the case. MDA has me move her over to the bed. She seems like she is starting to wake up (starting to grimace, RR increases). Suddenly volumes drop off, sat fall fast into the 80s. She super tight. Sat hits 65% - she looks pale. The OR nurse is horrified. MDA listens to lungs - bilateral breath sounds, no wheeze. MDA starts playing around with the sat probe. "Let's try her ear." I'm moving baby breaths - she so hard to ventilate - "are you sure the tube hasn't moved."

Gradually, without any real intervention, things improve. She easy to ventilate. She starts breathing well and opens her eyes. I pull the tube and she cries all the way to the PACU. She has no further problems.

What do you guys think was going on? The MDA felt that it was breath holding as she passed through stage II. Do you think I just had her too light during the case?