Clinical case: intraop hypoxemia during robot partial nephrectomy

[vector2]

So, doing my CA-3 board runner rotation and got called to a room to help out with this guy.

59yo M, 5'7", 250lb hx HTN, OSA with CPAP, >4 mets, normal EKG, nonsmoker presents for robotic L partial nephrectomy d/t 4x4x4cm mass suspicious for RCC found on CT following c/o hematuria. Normal PE except for distant breath sounds d/t pt's massive truncal obesity. Anticipated difficult airway cause he's got no chin and huge neck. Unable to pass tube with initial glidescope view, long story short he eventually required intubation with fiberscope/aintree through an LMA. Anyway, airway secured. Access includes 16g and 18g PIV. Plan is for opioid free anesthetic which includes lidocaine and precedex gtts, decadron, IV tylenol, toradol, ketamine.

Pt turned 180 degrees, and turned partially R lateral. The 38 or so trocars required to do this procedure are docked. Vitals at this time are BP 105/75, SpO2 100% on fi 100, HR 58. Peak pressures are 30-35 with Vt450-500. ETCO2 29-32. Case proceeds uneventfully for 20 minutes. Surgeon now tells you that there is a very small (and likely clinically insignificant) pinpoint hole in the diaphragm- you believe surgeon and chief urology resident because you trust them. Respiratory dynamics do not change for another 10 minutes.

Pt's peak pressures suddenly rise to 35-40 with same Vt. Sats now 78, able to manually bag up to 87-90. Bp 96/72, HR 62, ETCO2 same. Surgeon throws stitch through diaphragm hole, robot is undocked, and belly is exsufflated. Albuterol is administered. Sats remain low with vigorous bagging. Pt is adequately paralyzed. Breath sounds are still bilateral but distant similar to pre-op exam.

How do you proceed?

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[Noyac]

Imaging if you truly suspect PTX or have surgeon place CT if they don't want to undock.
Otherwise, tell the surgeon that his pt will not make it to the end of surgery.

 

[Ronin786]

I'd also try and turn him back supine if possible to help optimize respiratory dynamics and fix V/Q mismatch.

 

[Orin]

Ideally you'd have someone who knows how to drop an U/S on the chest and visualize a PTX but I'd opt more for an airway event than a PTX that started abruptly despite the obvious hole in the diaphragm.

My algorithm here would be to stabilize, crank the peep, and re-assess with insufflation. Bronch to r/o stuff if feasible.

My intraop PTX case developed slowly and the primary problem wasn't hypoxia. Most folks can oxygenate okay with one lung, but I was battling the tension physiology that developed when the resident nicked the diaphragm. They fixed that though when they got into the other side...

 

[cincincyreds]

While unique causes of pleural injury exist during laparoscopy, injuries to the diaphragm are uncommon during laparoscopic surgery.3–5 Most diaphragmatic injuries are apparent and clearly visible with the magnified laparo-scope. However, the only clue may be “billowing” of the diaphragm3 or clinical signs of pneumothorax, such as hypoxia or elevated airway pressures.

The important thing in a situation like this is to call for help and do a systematic review of what the problem can be.

First I would make sure to put this patient on 100% oxygen and make sure my pulse oximeter is appropriately attached. Then I would look around at things. Check the endotracheal tube and it's position along with the balloon. Use a fiberoptic scope if unsure to check position. Check the vital signs and check that the circuit is intact and in fact delivering oxygen along with adequate tidal volumes. Also look at the depth of the endotracheal tube making sure it is at a reasonable depth.

I would then use my stethoscope and listen to the breath sounds bilaterally. Being an obese patient it may not be able to hear the breath sounds and may warrant a CXR if I want to rule out a PTX. Also with auscultation I would listen for bronchospasm.

After auscultation I would feel my ambu bag to determine the complicance of the patients lungs.

I would also suction out the endotracheal tube for mucus plugs.

It's best to do a systematic review like this in order to rule out the cause of the hypoxemia. I did notice the patient was getting a tidal volume of 450-500, so it is possible the patient is being hypoventilated which can contribute to the hypoxemia. It wouldn't cause an increase in peak pressure. A tension pneumo would cause hypoxemia and increased peak pressures which could be treated by the surgeons with a chest tube. If the ETT is too deep I would pull it back. If the patient is bronchospastic I would give albuterol and assess what medications the patient has received as they could be having an allergic reaction to one of the medications. If the patient is having atelectasis I would do recruitment maeuvers. If the patient had an aspiration event I would continue with supportive care including peep.

 

[vector2]

Ideally you'd have someone who knows how to drop an U/S on the chest and visualize a PTX but I'd opt more for an airway event than a PTX that started abruptly despite the obvious hole in the diaphragm.

My algorithm here would be to stabilize, crank the peep, and re-assess with insufflation. Bronch to r/o stuff if feasible.

My intraop PTX case developed slowly and the primary problem wasn't hypoxia. Most folks can oxygenate okay with one lung, but I was battling the tension physiology that developed when the resident nicked the diaphragm. They fixed that though when they got into the other side...

While unique causes of pleural injury exist during laparoscopy, injuries to the diaphragm are uncommon during laparoscopic surgery.3–5 Most diaphragmatic injuries are apparent and clearly visible with the magnified laparo-scope. However, the only clue may be “billowing” of the diaphragm3 or clinical signs of pneumothorax, such as hypoxia or elevated airway pressures.

The important thing in a situation like this is to call for help and do a systematic review of what the problem can be.

First I would make sure to put this patient on 100% oxygen and make sure my pulse oximeter is appropriately attached. Then I would look around at things. Check the endotracheal tube and it's position along with the balloon. Use a fiberoptic scope if unsure to check position. Check the vital signs and check that the circuit is intact and in fact delivering oxygen along with adequate tidal volumes. Also look at the depth of the endotracheal tube making sure it is at a reasonable depth.

I would then use my stethoscope and listen to the breath sounds bilaterally. Being an obese patient it may not be able to hear the breath sounds and may warrant a CXR if I want to rule out a PTX. Also with auscultation I would listen for bronchospasm.

After auscultation I would feel my ambu bag to determine the complicance of the patients lungs.

I would also suction out the endotracheal tube for mucus plugs.

It's best to do a systematic review like this in order to rule out the cause of the hypoxemia. I did notice the patient was getting a tidal volume of 450-500, so it is possible the patient is being hypoventilated which can contribute to the hypoxemia. It wouldn't cause an increase in peak pressure. A tension pneumo would cause hypoxemia and increased peak pressures which could be treated by the surgeons with a chest tube. If the ETT is too deep I would pull it back. If the patient is bronchospastic I would give albuterol and assess what medications the patient has received as they could be having an allergic reaction to one of the medications. If the patient is having atelectasis I would do recruitment maeuvers. If the patient had an aspiration event I would continue with supportive care including peep.

At this point, recruitment maneuver was done with no improvement. Pt placed back on vent with increased peep and sats remain around 90 with still elevated peak pressures. ETCO2 28. Arterial line is placed and first gas on fi 100% is 7.36/35.4/67/20.3. Bronchoscope was called to room and ETT checked and seen to be in appropriate position. Only minor secretions noted. BP drops to 70/40 briefly, sevo turned down to 0.6 mac, ephedrine 20mg IV administered and bp responds appropriately and stays elevated. Pt is still in slight R lateral position at this time. Rads called to do a portable to evaluate L lung. Horrible oblique image of fat patient poorly positioned for said radiograph:

Clearly there's a small ptx there. A question to those who haven't seen many ptx's: Is this one clinically significant (enough to make a pao2 that was likely in the hundreds drop to 70)? Why or why not? Should a chest tube be placed?

And a question to staff anesthesiologists: Would you cancel the case at this point? Why or why not?

 

[urge]

At this point, recruitment maneuver was done with no improvement. Pt placed back on vent with increased peep and sats remain around 90 with still elevated peak pressures. ETCO2 28. Arterial line is placed and first gas on fi 100% is 7.36/35.4/67/20.3. Bronchoscope was called to room and ETT checked and seen to be in appropriate position. Only minor secretions noted. BP drops to 70/40 briefly, sevo turned down to 0.6 mac, ephedrine 20mg IV administered and bp responds appropriately and stays elevated. Pt is still in slight R lateral position at this time. Rads called to do a portable to evaluate L lung. Horrible oblique image of fat patient poorly positioned for said radiograph:

Clearly there's a small ptx there. A question to those who haven't seen many ptx's: Is this one clinically significant (enough to make a pao2 that was likely in the hundreds drop to 70)? Why or why not? Should a chest tube be placed?

And a question to staff anesthesiologists: Would you cancel the case at this point? Why or why not?

That pneumo does not look very impressive. Plus it should be from CO2. It should resolve before you put the chest tube. How does the other lung look on the x ray?

I would keep looking for another etiology.

Torsed lung?

The famous PE (that never is BTW!)?

Some sort of herniation through the diaphragm?

Bronchospasm?

Airway trauma from the Aintree?

Cardiac herniation?

I would get him flat and get x rays of chest and abdomen.

 

[urge]

So, doing my CA-3 board runner rotation

Board runner rotation? Is that officially recognized, or is it scut work?

 

[Ronin786]

I could be terribly off base here, but that PTX could still be significant given that you're in the lateral position. Your dependent lung is already experiencing significant mismatch and now you just knocked off the other lung with the pneumo.

I'd continue looking for other causes, but obvious things being obvious that's my answer.

 

[Scotty_G]

I don't know Ronin... We do single lung ventilation cases on people with unhealthy lungs. How often does the sat drop after 100% 02 and peep is applied? Not often unless there is something else going on. Besides the op mentioned the position is slight lateral so positioning is probably not the main issue. I agree the pneumo isn't that big but we need better images/supine position etc. If it's not a big pneumo I would consider what the other posters have mentioned. It could be a C02 embolism but that is pretty rare and you would probably be fighting the BP.

 

[deleted59964]

I'd start with A
--- use that bronchoscope and exclude endobronchial on turning first.
--- breath sounds that are "distant" can be misleading.

 

[urge]

I'd start with A
--- use that bronchoscope and exclude endobronchial on turning first.

They did that already.

Bronchoscope was called to room and ETT checked and seen to be in appropriate position. Only minor secretions noted.

 

[Chloroform4Life]

Start V-V ecmo. Proceed with case 😀.

This I think is a case of major shunting since your ventilation is adequate yet oxygenation on 100% fio2 is poor. You ruled out mainstem, which would be one of my first thought in a laparoscopic case (insuflation pushing lungs upward). I don't think the pneumothorax pictured would cause such significant shunting, however, when you combine it with an obese patient (poor thoracic compliance) and increased abdominal pressure, you can get some major atelectasis in both lungs. I would tell the surgeon the stop insufflation and be more vigorous with my recruitment maneuvers. One or two sustained pressure maneuvers may not be enough. You may need a few minutes of it. I would also place a pneumocath since that pneumothorax is not going to be helping you while you're trying to recruit those lungs.

 

[Planktonmd]

Patient had a diaphragmatic injury followed by hypoxia, low BP and increased airway pressure. The CXR is very crappy and done in some weird position, so even if the Pneumo doesn't look too bad on that crappy CXR you need to treat it.
So, place patient supine, insert chest tube, wait for the patient to stabilize (which will most likely happen in a few minutes), then proceed with open Nephrectomy and skip the robotic masturbation.
Why doesn't the patient have an epidural if you are trying to do a fancy "no opiate technique"???

 

[ArMed]

Mets to lungs? Smoker? Previously known A-a gradient? Was the absent response to albuterol enough for you to rule out bronchospasm? Was the hole made with a trocar or insufflation? Suspect any other occult damage? How about a TEE to help rule in PE or rule out tamponade physiology. If the problem persists despite discontinuing insufflation, and no alternative cause is identified, I would have surgeon put a chest tube and cancel case.

 

[vector2]

That pneumo does not look very impressive. Plus it should be from CO2. It should resolve before you put the chest tube. How does the other lung look on the x ray?...

I would get him flat and get x rays of chest and abdomen.

So in retrospect this was the obvious thing to do right off the bat, but as you all know, sometimes it can be a tougher decision in the heat of the moment to head in the direction of cancelling the case by taking the drape off, removing the trocars, unpositioning the patient and and getting some good films, especially when you're talking about a relatively young guy who likely has cancer that could be resected in 20 minutes once the initial dissection is done. Additionally, I think it was a good lesson in not latching on to your first diagnosis and only pursuing that workup. I mean, it was an obvious left diaphragm puncture, the patient showed signs of likely having a ptx, so we kept the patient in his half right lateral position with the drape on and tried to awkwardly shoot the suspected left lung without contaminating anything.

Anyway, after looking at the first film, everyone in the room concurred that there was essentially no way that a ptx of that size was causing this patient this level of respiratory insufficiency. Drape was taken off, trocars removed, patient placed supine and turned back from 180 so circuit extender could be taken off. Cooked another ABG that essentially revealed the same picture, and rads was called back into the room to do a proper AP and lateral.

Pt has a stone-cold normal PA cxr from one month ago, and as stated above, no history of any respiratory problems (other than OSA) up to and including the day of surgery. Differential?

 

[urge]

So in retrospect this was the obvious thing to do right off the bat, but as you all know, sometimes it can be a tougher decision in the heat of the moment to head in the direction of cancelling the case by taking the drape off, removing the trocars, unpositioning the patient and and getting some good films, especially when you're talking about a relatively young guy who likely has cancer that could be resected in 20 minutes once the initial dissection is done. Additionally, I think it was a good lesson in not latching on to your first diagnosis and only pursuing that workup. I mean, it was an obvious left diaphragm puncture, the patient showed signs of likely having a ptx, so we kept the patient in his half right lateral position with the drape on and tried to awkwardly shoot the suspected left lung without contaminating anything.

Anyway, after looking at the first film, everyone in the room concurred that there was essentially no way that a ptx of that size was causing this patient this level of respiratory insufficiency. Drape was taken off, trocars removed, patient placed supine and turned back from 180 so circuit extender could be taken off. Cooked another ABG that essentially revealed the same picture, and rads was called back into the room to do a proper AP and lateral.

Pt has a stone-cold normal PA cxr from one month ago, and as stated above, no history of any respiratory problems (other than OSA) up to and including the day of surgery. Differential?

Whatever that x ray is, it does not look good.

The diaphragm is up to t4, over the heart, and there is a huge air filled viscus in the belly. I would have to ask the radiologist to help me on that one. I don't want to be around when the patient farts, just in case.

PS: I still think there is some sort of diaphragmatic herniation.

 

[Chloroform4Life]

Can't tell if that's a high diaphragm on the right, or collapse of RLL. Ddx includes mucous plugging of RLL, atelectasis, aspiration pneumonia, pleural effusion. Also can't tell about ptx since top of lungs not included in pic but I guess that was not your main concern. I would bronch, looking deeper for mucous plugging. Try recruitment maneuvers. Ultrasound to check for effusion.

 

[PainDrain]

That looks to be a completely collapsed or infiltrated RML and RLL. You can still see some right diaphragm below on the right. The stomach is rather distended and the heart appears to be shifted left. Nothing as dramatic in the left lung.

 

[vector2]

Woops, forgot the AP that actually showed the chest. The other film is all jacked up and hard to interpret cause it's zoomed and still slightly obliqued:

 

[urge]

Woops, forgot the AP that actually showed the chest. The other film is all jacked up and hard to interpret cause it's zoomed and still slightly obliqued:

RUL collapse and mediastinum pushed to right chest. Diaphragm looks in better position now, which makes me think the previous one was in inspiration.

Left pneumo is bigger but not horrible.


I'm glad the guy is fat. The bone structure of the neck makes him look like an alien.

 

[meister]

Clearly the ET tube occluded his pig bronchus.

 

[Chloroform4Life]

Clearly the ET tube occluded his pig bronchus.

No. ETT is in correct position, about 3 cm above carina. Unless this patient has a RUL take off at that point, which would be very unlikely. Could be mucous plugging of the RUL though. These x-rays look so different. Are they even of the same patient?

BTW, that NG tube positioning looks strange. either in lung or esophagus, but not stomach.

 

[deleted162650]

Going off of some first hand experience, nothing good can come from a urologist being in the chest. Quote from butcher urology attending in residency "Where am I, where am I? Oh, the lung."

 

[deleted59964]

They did that already.

Yep - posted after a busy night ... Never mind me

 

[dhb]

PTX obvious from clinical history.

 

[Planktonmd]

This was supposed to be a left nephrectomy and supposedly you had a left sided diaphragmatic injury, but now you have a right sided pleural effusion on the supine CXR!
Did they use a lot of irrigation fluid that entered the chest and followed gravity to the right side?
Also the pneumo on the left is more is more significant now.
I am baffled why a chest tube has not been inserted on the left yet despite the obvious clinical indication!

 

[vector2]

I know the picture quality is terrible and you can't manipulate it like you could it PACS, but that is not a worsening ptx on the left. There are still lung markings going into that shadowed area, albeit faint. I'll post the outcome and final diagnosis later today.

 

[PainDrain]

RCC does preferentially spread to the lung, a consideration.

 

[urge]

RCC does preferentially spread to the lung, a consideration.

It is possible. I would be surprised if he had a normal x ray a month ago. If that is a consideration then I would suggest to take the patient to the CT scanner. Hopefully his oxygenation is better being supine.

 

[Noyac]

The OG tube doesn't look right at all. Is this blood in the R chest?

 

[urge]

The OG tube doesn't look right at all. Is this blood in the R chest?

I thought it was ok. Just deviated right by the mediastinum.

I would seek radiology input to solve this matter.

 

[deleted162650]

Looking at the clavicles makes me think the film is a little rotated so I'm not sure how deviated things actually are. Either way with that film and those ABG's there is no way this case is proceeding.

 

[deleted162650]

Another clinical pearl with regards to RCC: These tumors like to go intraluminal into the renal vein, and once there, can sometimes extend rather rapidly into the IVC. They can extend fast enough that what was just a little tumor in the vein on pre-op CT is now well into the IVC by the DOS. I think any RCC with an intraluminal component should get a TEE prior to incision to r/o IVC tumor. You don't want a crossclamp sending a nice chunk of tumor to the lungs. Also remember that PE can initially manifest as bronchospasm.

I don't think that's what's going on here, just something to keep in the back of your mind on these cases.

 

[deleted162650]

Oh and P.S., that X-ray tech needs to be fired. Every image has one side getting cut off.

 

[urge]

1 now you have a right sided pleural effusion on the supine CXR!

2 I am baffled why a chest tube has not been inserted on the left yet despite the obvious clinical indication!

1 I don't see a right pleural effusion.

2 I wouldn't put a tube for a CO2 pneumo. Especially if not that big. His issue is the right lung. It is barely inflated.

 

[urge]

Oh and P.S., that X-ray tech needs to be fired. Every image has one side getting cut off.

Spinus processes are midline. I think it is centered.

The guy is fat.

 

[Planktonmd]

1 I don't see a right pleural effusion.

2 I wouldn't put a tube for a CO2 pneumo. Especially if not that big. His issue is the right lung. It is barely inflated.

Remember the CXR is in the supine position so don't expect to see the typical effusion picture in the lower part of the hemithorax.
And as for putting a tube for a CO2 pneumo , if the patient is hypoxic and hypotensive you need to treat all the possible causes because you might not have enough time to be an internist or a philosophe here!

 

[Laryngophed]

I know it was floated earlier, but a collapsed RUL here makes me wonder if the patient doesn't have a variant anatomy with a tracheal (rare, but I'm positive I've read about it) or very early R mainstream takeoff for the RUL. Could OP visualize the RUL on bronchoscopy?

 

[meister]

The films are pretty bad but intraop studies are difficult so you can't fault the tech too much. There's a deep sulcus sign on the left which likely reflects the PTX. Vague lucency over the abdomen makes me think retroperitoneal/peritoneal air, considering the patient's actively having a nephrectomy. Certainly RUL collapse which has a variety of causes you all know well (including a pig/tracheal bronchus which I'm not sure you can dismiss so easily here plus I have yet to see one in the wild so I'm gonna include it). The NG tube is at the GE junction and the stomach is distended with air.

I like tumor thromboembolus.

 

[Chloroform4Life]

The films are pretty bad but intraop studies are difficult so you can't fault the tech too much. There's a deep sulcus sign on the left which likely reflects the PTX. Vague lucency over the abdomen makes me think retroperitoneal/peritoneal air, considering the patient's actively having a nephrectomy. Certainly RUL collapse which has a variety of causes you all know well (including a pig/tracheal bronchus which I'm not sure you can dismiss so easily here plus I have yet to see one in the wild so I'm gonna include it). The NG tube is at the GE junction and the stomach is distended with air.

I like tumor thromboembolus.

Lol I understand what you were trying to say now. I thought when you said pig bronchus, you were referring to his obesity.

 

[deleted171991]

Another clinical pearl with regards to RCC: These tumors like to go intraluminal into the renal vein, and once there, can sometimes extend rather rapidly into the IVC. They can extend fast enough that what was just a little tumor in the vein on pre-op CT is now well into the IVC by the DOS. I think any RCC with an intraluminal component should get a TEE prior to incision to r/o IVC tumor. You don't want a crossclamp sending a nice chunk of tumor to the lungs. Also remember that PE can initially manifest as bronchospasm.

I don't think that's what's going on here, just something to keep in the back of your mind on these cases.

I remember doing in residency a RCC case where the clot burden extended up into the thoracic IVC. The patient had an incision like a gutted pig, and we went on bypass.

 

[vector2]

Fortunately for the patient, this was not an IVC thrombus that went to the lung. And those of you who pointed out the location of the OG were correct. Official rads read for the first supine chest:

"
Devices:
- Endotracheal tube tip lies between the thoracic inlet and carina in good location.
- Tip of the NG tube is above the GE junction with the proximal port at the level of T7. This could be advanced 15 cm to ensure that the proximal port is below the GE junction.

Findings:
There is right upper lobe atelectasis new since 2/29/2016 at 1542 hrs. I suspect this is due to mucous plug causing postobstructive atelectasis in this ventilated individual; I recommend vigorous suction.

There is slight rightward mediastinal shift that is likely the consequence of the right upper lobe atelectasis described above.

No convincing evidence of left pneumothorax identified on the current study. In my report of the earlier examination of the left hemithorax acquired today at 1032 hrs. I discussed the possibility of left pneumothorax; it is not excluded on the current examination.

There is pneumoperitoneum on crosstable lateral view of the abdomen."

Case was aborted at this time and patient sent to ICU intubated. He got a proper bronch when he got up to the room in which a small amount of mucous was suctioned from his (anatomically normal) right upper takeoff, but certainly not an amount that's usually associated with most symptom causing mucous plugs. There was also a thought that there was some acute chemical pneumonitis component secondary to a slow aspiration during the prolonged securing of the airway (only takes 20cc of aspirate to do some damage) but this was probably less likely. After suctioning, another portable was obtained in the unit:

read: "Endotracheal tube is in good position. NG tube not well seen distally with a probability it is in the gastric fundus. Fluid density seen in the minor fissure. There some blunting of both costophrenic angles. The lungs appear congested. There is more congestion now than on Mar 08, 2016 at 1127 hrs. Overall appearance of the study is improved with less fluid density in the right pulmonary apex since prior study. "

Patient improved significantly but remained intubated on PSV Fi 60% in the ICU because he was scheduled to go today for an open procedure. He's actually in the OR now with a pao2 of 130 on 40%, so there may be hope of extubating in the OR or at least very soon when he gets back to the unit.

 

[deleted171991]

Beautiful initial rads report.

 

[Chloroform4Life]

Beautiful initial rads report.

I know right? My radiologist would say "white out of RUL. Needs clinical correlation"

 

[vector2]

Beautiful initial rads report.

She's probably the best body CT radiologist in the hospital according to my rads buddy and definitely the one I'd want reading a family member's scan. You can imagine what her CT chest/abd/pelvis w/wo reads are like if this is what she dictates for a plain film.

 

[meister]

Never seen a rad recommend vigorous suction before. That would get you cross eyed looks around these parts.

 

[Ezekiel2517]

that film clearly shows collapse of the lobe 2/2 mucous plugging. Why didn't you simply bronch him in the OR, get rid of the plug, reexpand his lungs, and proceed with the case? That takes all of 5 min. instead you kept him intubated for another day (days?) and then bring him back to the OR and subject him to an open procedure.

 

[urge]

that film clearly shows collapse of the lobe 2/2 mucous plugging. Why didn't you simply bronch him in the OR, get rid of the plug, reexpand his lungs, and proceed with the case? That takes all of 5 min. instead you kept him intubated for another day (days?) and then bring him back to the OR and subject him to an open procedure.

Did you see the mucus plug?

 

[Ezekiel2517]

Did you see the mucus plug?

Even if you can't see it, in this clinical context, you should know that this is a plug. Unless this pt grew an obstructing tumor over the past 5 min you don't know about