Intraoperative Hypoxemia

[VentdependenT]

---

Members don't see this ad.

We have covered the 5 major catagories of hypoxemia (fio2, shunt, dead space, DLCO, hypoventilation) and they are conceptually clear to me however how long can you let hypoxemia go before you start needing to throw on some depends?

For example: Healthy individual. Extubation time. Cough, buck, bite, you give propofol and try to extubate but pt still not relaxing. Has been about 45 seconds sats now holding at 83 with you ventilating....does that make you nervous? I am not trying to go into succinyl and laryngospasm, just sats.

I would imagine those sats could hang there all day without inciting ischemia. Well above Sv02 of 75% and its not dropping. This is relative hypoxemia correct?

What if you were at 50% for 2 minutes.

Brain is dead after 4-5 min of ischemia correct? What about this relative hypoxemia stuff?

 

[ultraconsrvativ]

I would imagine those sats could hang there all day without inciting ischemia. Well above Sv02 of 75% and its not dropping. This is relative hypoxemia correct?

With coughing, bucking and biting they're probably tachycardic, hypertensive and their O2 consumption is probably escalating rapidly which means your SvO2 is probably sinking and you need the sats higher than the low 80s to prevent ischemia. The myocardium extracts a great deal of O2 leaving little wiggle room if your sat is low 80s.

 

[militarymd]

Hypoxia is tolerated quite well.

Go to the ICU, and check out some of the patients with severe ARDS...and see how hypoxic they are and for how long.....and they survive.

 

[Tenesma]

or go skiing in the rockies - and measure your sats... on some peaks your sats are between 75 and 85 % for HOURS and HOURS while you are skiing w/ massive oxygen consumption... so who cares about a sat in the 80%s??? well I care primarily for one reason - there is a good chance that you have this guy on 100% FIO2 prior to extubation and because of your poor ventilation he has become hypercarbic.... As soon as you extubate him to Room Air his sats are going to drop even more because of the high PaCO2.... (this statement is based on a formula that you should know by now)