Oral boards

He presents a patient who underwent AAA repair 4 days ago who now is oliguric and the BUN and creatinine are elevated. He asks me for the possible causes. We then have a long discussion on the differential diagnosis of acute renal failure. I mention the terms prerenal, post renal, and renal. I say that prerenal causes would include hypovolemia, low cardiac output from MI or CHF, renal artery occlusion, intra-op atheroembolism. I ask if the AAA was infrarenal. He said that the cross clamp was infrarenal. He says the U/A shows casts. I said sounds like ATN. He asked what that was. I said it's an intrinsic renal dysfunction due to tubular injury. Like what? I said he could've had an ischemic injury while he was hypotensive in the OR. I also mentioned nephrotoxic drugs. What would you do? I said I'd try to optimize his volume status and C.O. and stop any nephrotoxic drugs. He says that doesn't work. I said I'd give him lasix to try and convert him to nonoliguric renal failure. I also consider renal dose Dopa. He says that doesn't work and his K+ is 5.5. How can you lower his K+? I say for 5.5 I'd give kayexelate. He asks how else. I mention insulin/glucose, bicarb, Ca++, and dialysis (I forgot hyperventilation if intubated). He says that none of this works and the patient is volume overloaded. I suggest hemodialysis. He asks how I would get dialysis access. I said I'd use a temporary intravenous catheter. He asked me to describe how the catheters work. I said dual lumen central venous catheter with a staggered tip. He asks where I would place catheter. I said first choice was right IJ. He asked why. And I said it's a straight shot to the SVC/RA. He asked where else. I said subclavian, femoral. So now the patient is getting dialyzed and the patient decides he doesn't want to "undergo" dialysis. He asks me what I would do. I asked if the patient was competent. He was. I said if he was competent and refused dialysis I would not dialyze him. I added that I would attempt to persuade the patient to have dialysis. I said I would explain that ATN usually resolves and it is unlikely to be permanent. He then tells me that the patient's family insists that he be dialyzed. I say that I'd still honor the patient's wishes. He then asked me when I would consider placing a long term access. I said that since ATN was likely to resolve I would wait. He asked how long. I said at least one month. I pointed out that temporary catheters can last weeks. He says I examine the patient's abdomen and it's tensely distended. I mention abdominal compartment syndrome. How would you diagnose? I say physical exam and measure intra-abd pressure with Foley. He says it's 40. I say that I'd take the patient to the OR, open his incision, and close him with a big patch. He asked what kind of patch. I said Dexon mesh.

Me: Is there any other pertinent historical information? No problems with the surgery?JF: The history is as I told you. The patient is otherwise fine, extubated, alert.Me: Then I would proceed with physical exam, listen to breath and heart sounds, concentrating on abdominal exam.JF: He has a low-grade temp, heart and lung sounds are fine; on abdominal exam he has bowel sounds, some mild to moderate tenderness in the LLQ.Me: I want to do a rigid sigmoidoscopy.JF: You see several patchy areas of erythema and duskiness in the sigmoid colon.Me: It sounds to me like you're not describing full thickness necrosis of the bowel wall. At this time I want to get a CBC; I would start a second-generation cephalosporin and attempt to manage this non-operatively, with serial abdominal exams, CBC's and close observation.JF: On the second day the pt c/o ongoing abdominal pain, low grade fever and he passes some more guaic positive stool.Me: And his physical exam?JF: He still has LLQ tenderness.Me: If it the same, or better, I would continue antibiotics and treat him expectantly.JF: Let's say the tenderness is slightly worse.Me: Then I would take him to the OR for ex lap.JF: On ex lap you see that the sigmoid colon is somewhat dusky.Me: I would do a sigmoid colectomy with an end colostomy and Hartman's pouch.JF: On this pt with low-grade fever and a fresh AAA repair, do you want to examine the graft?Me: Yes. [Thinking] No. In fact, I would make an effort not to disturb the aneurysm sac with a fresh graft in it, since I am doing a contaminated case.

successful repair of a ruptured aneurysmwho became oliguric and bumped his creatinine. We then had a lengthy discussion about the work-upfor acute renal failure. He wanted to know possible causes (ATN from hypotension, aorticcross-clamping, drugs, hypovolemia, vascular accidents involving the renal arteries). He asked me which drugs. We discussed treatment with a Swan-Ganz catheter, rehydration, low dose dopamine, eliminating all nephrotoxins (he asked which drugs in particular I was looking for), attempting to convert him to non-oliguric renal failure with Lasix, how to r/o vascular events (I eventually got a nuclear flow scan), and what my indications for dialysis are. At one point he asked what Swan-Ganz values I thought were likely to be reasonable. I felt that this went well. Also, I've been told that the 2nd room usually revolves around acute care ICU management, etc. As in the previous room, time flew by once we got started.

I ask if he has a history of AAA. Nope. I examine him and he has a pulsatile LUQ mass. I put in two large IVs, draw blood for type and cross, and order O neg blood. We go to the OR and he asks me to describe exactly what I'd do starting with positioning. I say supine, and prep from chin to knees, and drape so I have access to his chest and both groins. He asks me if the patient was asleep yet. I said no, that I'd prep him awake. He then crashes and I open thru a midline incision. I find a huge contained retroperitoneal hematoma. I say that I'd get proximal aortic control at the hiatus. He asked me to describe, in detail, how. I said I'd mobilize the left lobe of the liver by dividing the triangular ligament, then retract the stomach inferolaterally and enter the lesser sac thru the gastrohepatic ligament. Then I'd retract the GE junction to the left and divide the crura to expose the aorta. He says I get a clamp on the aorta and the BP improves. I then mention reflecting the left colon to expose the neck but say that I would directly approach the AAA anteriorly. He says I move my clamp down below the renal arteries and asks how I'd control the iliacs. I say I'd dissect them and clamp. Alternatively, I said, I could control them from inside the AAA with Foley catheters. I scooped out the thrombus and sutured the lumbars. He then asked what my preferred operation would be. I said I'd try and put in a tube graft. He said I sew in a tube graft and I notice that there is a large IMA with very poor back-bleeding. I said I would reimplant the IMA. How? I said I would create a Carrell patch and sew it end-to-side to my aortic graft. That's all folks.

I told them this was a ruptured AAA and the patient needed to go to the operating room. He asked me what the differential diagnosis was. I told him it included ruptured AAA, myocardial infarction, acute mesenteric ischermia or acute pancreatitis. Other than getting an EKG, the patient needed to go to the operating room. He said okay, how would you proceed. I accessed the peritoneal cavity through a vertical midline incision and saw a ruptured AAA. I obtained control of the supraceliac aorta by mobilizing the left lobe of the liver, made sure the patient had an NGT in place, dissected out the supraceliac aorta and placed a clamp. I followed this by dissecting down on top of the aneurysm, then laced a clamp on the infrarenal aorta and removed the supraceliac clamp. I dissected out the common iliac arteries. These were not aneurysmal. I placed clamps on these and proceeded with a tube graft repair. I closed the old aneurysmal wall around the graft and then closed the abdomen with retention sutures. The patient did fine until post-op day #5. The patient started complaining of left lower quadrant pain. I obtained an abdominal CT scan; it was consistent with an ischemic left colon. I performed a flexible sigmoidoscopy. This revealed areas of deep ischernia in the colon consistent with grade 1H or IV ischernia. I took the patient back to the operating room and performed a left hemicolectomy. He asked me what my margins would be. I told him that would be largely based on the level of ischemia, as well as the blood supply to the remaining colon, but that I would probably excise the splenic flexure and base the blood supply of my colostomy on middle colic artery. I would excise the colon distally down to the rectum.