Postop Hypoxia

[SilverStreak]

We see this complication the most in our CABG population. They roll out from the OR, standard vent settings: fi02 100%, PS 10, rate 10, Tv weight based, no peep. We get a gas few minutes after arrival to the unit. Routinely we'll see PO2 in the 90's range on 100% (majority have no underlying lung disease or predisposition of being undiagnosed lung disorder), so typically we'll place pt on about 5 of peep, then slowly wean to extubate. Our wean goal for these pts is 6 hours.

Usually at 6 hours, after adding peep, pt waking up, we'll have a better but still low PO2, so pt will go on venti mask. We give quite a bit of volume to the hearts both intraop and post op recovery period, so I know that's a factor. I'm also assuming there's some shunting going on, and being on pump will affect oxygenation. We check H/H frequently, usually not related to low hemoglobin carrying capacity. Chest sounds usually clear and often diminished, PA numbers usually 20s/10s.

By post op day 2 we're over the hump so to speak, usually got the heart pumping good now and we're diuresing the fluid we slammed pt with during op period. Lately quite a few of them have ended up being "watched" in the ICU simply because of persistent hypoxia and O2 demands. Pt is stable, not SOB, not in any type of distress, just needs the extra burst of O2.

My question is, do you guys have any other suggestions for the persistent hypoxia we see lasting so long? With steady aggressive diuresis, these pts don't seem to be fluid overloaded-CXR clear, lungs clear,I & O equalizing, no (or very minimal edema) but they remain hypoxic. Many end up getting pulmonary consult who just says keep em on O2 and aerosols for mild to moderate hypoxia, no explanation of what's causing it. Patients for the most part end up doing find and transferring to the floor, I just wonder what's the underlying factor. Do you guys commonly see this hypoxia post operatively?

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[militarymd]

We see this complication the most in our CABG population. They roll out from the OR, standard vent settings: fi02 100%, PS 10, rate 10, Tv weight based, no peep. We get a gas few minutes after arrival to the unit. Routinely we'll see PO2 in the 90's range on 100% (majority have no underlying lung disease or predisposition of being undiagnosed lung disorder), so typically we'll place pt on about 5 of peep, then slowly wean to extubate. Our wean goal for these pts is 6 hours.

Usually at 6 hours, after adding peep, pt waking up, we'll have a better but still low PO2, so pt will go on venti mask. We give quite a bit of volume to the hearts both intraop and post op recovery period, so I know that's a factor. I'm also assuming there's some shunting going on, and being on pump will affect oxygenation. We check H/H frequently, usually not related to low hemoglobin carrying capacity. Chest sounds usually clear and often diminished, PA numbers usually 20s/10s.

By post op day 2 we're over the hump so to speak, usually got the heart pumping good now and we're diuresing the fluid we slammed pt with during op period. Lately quite a few of them have ended up being "watched" in the ICU simply because of persistent hypoxia and O2 demands. Pt is stable, not SOB, not in any type of distress, just needs the extra burst of O2.

My question is, do you guys have any other suggestions for the persistent hypoxia we see lasting so long? With steady aggressive diuresis, these pts don't seem to be fluid overloaded-CXR clear, lungs clear,I & O equalizing, no (or very minimal edema) but they remain hypoxic. Many end up getting pulmonary consult who just says keep em on O2 and aerosols for mild to moderate hypoxia, no explanation of what's causing it. Patients for the most part end up doing find and transferring to the floor, I just wonder what's the underlying factor. Do you guys commonly see this hypoxia post operatively?

99.5% of post-op hypoxia is from atelectasis...cabg cases....lungs are deflated for the duration of the pump run.

Treatment is Incentive spirometry and out of bed in chair orders.

 

[SilverStreak]

99.5% of post-op hypoxia is from atelectasis...cabg cases....lungs are deflated for the duration of the pump run.

Treatment is Incentive spirometry and out of bed in chair orders.

I understand that as well, and we really push pulmonary toileting in these patients especially. Often, several days later pts will still be hypoxia and lungs will be fully reinflated.

 

[militarymd]

atelectasis can sometimes take DAYS to clear.

 

[Noyac]

I understand that as well, and we really push pulmonary toileting in these patients especially. Often, several days later pts will still be hypoxia and lungs will be fully reinflated.

How hypoxic are you talking? Are you at elevation?

 

[Laryngospasm]

How hypoxic are you talking? Are you at elevation?

What do the blood gases, if any, show? COPD? My vote is atelectasis post CAB.

 

[ThinkFast007]

What do the blood gases, if any, show? COPD? My vote is atelectasis post CAB.

bump

 

[SilverStreak]

What do the blood gases, if any, show? COPD? My vote is atelectasis post CAB.

The typical patient in this example I'm talking about aren't COPDers. If they are, usually we'll have pulmonary on the case to begin with, and then of course if they were the hypoxia wouldn't be a concern since COPDers are chronically hypoxic on gases.

It's not uncommon to see a pO2 of 60-70's, keeping in mind the patient is on 50% fiO2 or better. I didn't really think much about the first few patients at for several reasons. One, they're stable on the O2 they're getting, not air hungry or SOB, satting okay, they're not wet and need diuresing. Two, everything else on the gases looks okay, ph in range, no metabolic issues going on. I figured it was just hypoventilation post op from incision and chest tube pain, maybe some shunting from bypass. About a month ago, an on call cardio surgeon was rounding, and I had one of these patients, he said lets get pulmonary on the case to see if we're missing anything. He was worried about possible pulmonary edema, but there were no indications of that at all. It just left me wondering if maybe there was another explanation besides atelectasis...

 

[SilverStreak]

How hypoxic are you talking? Are you at elevation?

Nope, in the south.

 

[SilverStreak]

I'll give you guys a similar example on how weird these CABs can be sometimes wit gases/vent wean.

Had a 50 yo last week came out at 2300 cab x 4, routine hx- cad, htn, never smoked, no asthma or lung problem. We get gases on arrival-- looked great ph normal, co2 40's, po2 300's on 100% fio2. We start weaning, we aim for mean extubation of 6 hours, give or take on our hearts. We're doing fine until about 0200, had been weaning rate/02 with no problems, anticipating CPAP then extubation soon. All of a sudden, RT weaned my o2 from 50-40%, his sats start dropping 80-90's range, we play with him-suction in line, add some peep, give an aerosol tx, end up having to go back up to 100% to maintain a sat above 95%.

We got gases, CXR, labs, waiting on my results to call the surgeon and let him know what's going on. There were no changes whatsoever in hemodynamics, volume status, lung sounds, CXR, but after weaning for 2 hours just fine my next po2 is low 70's range on 100%. After I get all the results, call surgeon and he wants pulmonary consult in am, can't explain what happened. I realize we don't always know the answers, but I'm one of those who likes to know what's going on and why.

 

[militarymd]

like I said before....atelectasis

 

[militarymd]

or PE

 

[salibabe]

Hi my father, 70 years, had CABG operation few days ago (3 days) and his Po2 level (taken via blood test) is v low with 100% oxygen. last reading was 68, doctors say it should be in 200s. The surgeons are not sure why this is happening.lung saturation (on the screen) is around 93-97% with 100% oxygen, but drops significantly to 87% ( or lower without the oxygen mask). chest xrays so far have been clear but 1 taken yesterday shows some changes. He doesn't have SOB r any symptoms. He is not a smoker and doesnt suffer from asthma (or any lung dx preoperatively). He has always had a cough every now and then when phelgham (before operation). Now he is still has the cough (with phelgham). They are suspecting PE or pneumonia (C&C sent to lab results expected in 2 days). the docs have started blood thinners (risky!) and antibiotics (precaution). They are not able to do chest CT ( to rule out PE) cuz of his condition ( can not be transferred out of ICU and on 100% O2). has any doctor/ surgeon experienced that before? can some one send me other possible d/d? or a good article to read? my email id is [email protected]. awaiting reply. many thanks. sal

 

[WholeLottaGame7]

Hi my father, 70 years, had CABG operation few days ago (3 days) and his Po2 level (taken via blood test) is v low with 100% oxygen. last reading was 68, doctors say it should be in 200s. The surgeons are not sure why this is happening.lung saturation (on the screen) is around 93-97% with 100% oxygen, but drops significantly to 87% ( or lower without the oxygen mask). chest xrays so far have been clear but 1 taken yesterday shows some changes. He doesn't have SOB r any symptoms. He is not a smoker and doesnt suffer from asthma (or any lung dx preoperatively). He has always had a cough every now and then when phelgham (before operation). Now he is still has the cough (with phelgham). They are suspecting PE or pneumonia (C&C sent to lab results expected in 2 days). the docs have started blood thinners (risky!) and antibiotics (precaution). They are not able to do chest CT ( to rule out PE) cuz of his condition ( can not be transferred out of ICU and on 100% O2). has any doctor/ surgeon experienced that before? can some one send me other possible d/d? or a good article to read? my email id is [email protected]. awaiting reply. many thanks. sal

Unfortunately this thread will be locked soon, because you're not allowed to ask for advice on SDN. Surgery for a loved one is scary, but as you can see from this thread, your father's condition is not out of the ordinary and I'm sure he's in good hands. Best of luck.

 

[Arch Guillotti]

Closing. Necrobump for medical advice.