Aortic Operative Stuff

Posted by: “Dr.Mohamed El Tahan”

on Anesthideas

  However, did your surgeon prepare the bypass machine with extra reservoir !. In reality, as your description this is ATA III post traumatic aortic dissection and massive bleeding is normal. First, i would to clarify this missed point which raised by Dr. Bilal and you, this may be related to my unclear initial post. We are talking here about “Traumatic Aortic Transection” which named as “Dissection” or less accurately “Rupture” without presence of any aneurysmal dilatation or dissecting aneurysm. This usually results from the blunt chest trauma after deceleration injuries of the isthmus of the aorta because of its tight attachment to the ligamentum arteriosus which is the obliterated ductus arteriosus. This isthmus injury may extend in both caudal direction to the descending aorta and cranial direction to involve the left subclavian artery and rarely the carotid artery. [Kyobu Geka. 1991 Oct;44(11):965-8., Eur J Vasc Endovasc Surg. 2006 Jan;31(1):18-27.] Second, we could not apply neither the Debakey classification of aortic dissections nor the Crawford classification of thoracoabdominal aortic aneurysms (TAA) to this type of injury. So, simply the present case was not at all TAA class III (aneurysms involve the lower portion of the descending thoracic aorta and most of the abdominal aorta). Svensson et al., class 5 would be the best description of the present injury. (class 1: classic aortic dissection, class 2: intramural

hematoma /hemorrhage, class 3: subtle-discrete aortic dissection, class 4: plaque rupture and ulceration, and class5: traumatic and iatrogenic aortic dissection). [Circulation 1999; 99:1331-1336] We had 23 cases since 2007 in my current referral center with intraoperative death of one case (before exploration) and 3 deaths after surgery because of other trauma related morbidities such as sepsis, ARDS and ventilation-associated penumonia. More than 50% of these case were presented with late aortic transection in similar to Kallistratos et al. [Am J Emerg Med. 2011 Sep 9]. I have involved in the intra-operative of 13 cases of them. All of them were approached through left throacotomy with one lung ventilation (my routine) or two lumg ventilation (by some colleagues) and surgery varied from simple repair, synthetic grafting and/or repair of the subclavian and carotid arteries. We did not use any of the distal aortic perfusion techniques such as passive or active shunts (between the proximal and distal aorta), left heart bypass (left atrium-femoral artery), and partial of full cardiopulmonary bypass (femoro-femoral). In all cases, cardiopulmonary bypass was present in the OR but not primed. The aortic cross clamp time was less than 30 min in 21 cases and was 40 min in 2 cases including the present case. Two cases developed postoperative short term renal impairment. No case had either early or late paraplegia. In Egypt, at my original tertiary Mansoura Emergency Hospital in the Middle of Nile Delta we have about 9-14 cases annually. I have only an old statistics for the estimated annual incidence of aortic transection of 7500 to 8000 cases in the United States in 1989 [Ann Thorac Surg 1989; 48: 1–2.]. As Joe mentioned before, there is no doubt that thoracic endovascular aortic repair (TEVAR) has lower Major respiratory complications and shorter hospital stays than with the traditional direct thoracic aortic repair (DTAR). Unfortunately, we do not have expert surgeon or interventionist to do them. [Arch Surg. 2012 Mar;147(3):243-9, Eur J Vasc Endovasc Surg. 2006 Jan;31(1):18-27.] I would not allow the surgeon to open the chest before he done a double circulation canulation taking the right subclavian artery as upper circulation which will allow you to keep the brain with the upper body perfused and then the right femoral artery canulation will assume the kidney and lower body circulation. Femoral vein canulation for veinous circulation. When every the bypass is ready and connected I would allow the thoracotomy. I let the patient cool down till 34 C, give a full dose heparin to the patient and let him start. First; Augoustides JG, Pantin EJ and Cheung AT in their chapter no. 21 “Thoracic Aorta” in the Kaplan’s Cardiac Anesthesia Textbook, 2010, Pages 638-38, clarified that Standard CPB can be used for the repair of aneurysms limited to the aortic root and ascending aorta that do not extend into the aortic arch. Aneurysms that involve the aortic arch require CPB with temporary interruption of cerebral perfusion (DHCA). Aortic aneurysms of the descending thoracic aorta require lateral thoracotomy for surgical access. Aneurysmal resection requires cross-clamping with or without distal aortic perfusion. Second; the use of simple cross clamping without distal perfusion techniques or the need for partial or full heparinization is recommended for the aortic transection in expert centers with expected clamping time less than 30 min. [Kyobu Geka. 1991 Oct;44(11):965-8., J Cardiothorac Vasc Anesth 2001; 15(6): 761-763, Ann Thorac Surg 1985; 39:37.]. Moreover, Augoustides JG, Pantin EJ and Cheung AT wrote “despite its physiologic consequences, this technique remains popular because it is simple andhas proven clinical outcomes”. Third; Estrera et al. concluded in their retrospective review that the use of the combined adjuncts of CSF drainage and distal aortic perfusion has all but eliminated the incidence of immediate postoperative neurologic deficit in nonemergent patients withaneurysms of the descending thoracic aorta. These results showed be interpreted with cautious in the view of its retrospective and non-randomized methodologydesign. [Ann Thorac Surg 2001;72:481– 6] Fourth, there is very nice description by Norris EJ in his interesting chapter of “Anesthesia for Vascular Surgery” in the Miller’s Anesthesia Textbook, 2009, as follows; – Descending thoracic and thoracoabdominal aortic surgery can be performed without extracorporeal support (i.e., left heart bypass or cardiopulmonary bypass). Large series of the “clamp-and-sew†technique have been published with relatively favorable outcomes, but these cases are from institutions with the greatest clinical experience and the shortest cross-clamp times. Advocates of this technique favor its surgical simplicity. -Other than the location and extent of the aneurysm, the duration of cross-clamping on the aorta is the single most important determinant of paraplegia and renal failure with the clamp-and-sew technique. Clamp times ofless than 20 to 30 minutes are associated with almost no paraplegia. [J Vasc Surg 1986; 3:389-404., J Thorac Cardiovasc Surg 1981; 81:669-674.] When clamp times are between 30 and 60 minutes (the vulnerable interval), the incidence of paraplegia increases from approximately 10% to 90% as time progresses. My last patient ATA III have received 29 RBC, 18 FFP 32 PLT. I usually put continuous tranxenamic acid. I totally agree that blood loss during TAA repair can be profound which necessitates the use of antifibrinolytic, intraoperative cell salvage, autologus blood transfusion and other blood conservative strategies. This will be correct with the use of phlebotomy to collect the patient’s blood on the reservoir of the bypass or with the use of full bypass rather than the other distal aortic perfusion techniques. I am a fan of tranexamic acid after withdrawal of approtonin. Unfortunately, it was out of stock during the doing of the present case. There was only 500 mg remaining!! I miss if you insert a CSF catheter drainage (this would help for the postoperative managment ) Omar, you raised an important issue of long debate in the literature as i will show now. But, i agree with you if it was Crowfiel TAA class III, there is no doubt this would necessitate lumbar drainage to CSF pressure of 10 mm Hg rather than 15 mm Hg, pressure transducer zero-referenced to the midline of the brain and to use any of the above distal aortic perfusion techniques as needed. [Augoustides JG, Pantin EJ and Cheung AT, Anesth Analg 2010;111:46 –58] The answer of your question is “No i did not use it for that emergent surgery, especially in the view of short duration of cross clamp”. You can find below similar evidences. I reserve its use of TAA class III and IV rather than transections. As you know the concept behind the use of CSF drainage it to augment the spinal cord perfusion pressure (SCPP) during aortic cross clamp for thoracic aortic surgery as SCPP = MAP – CSF pressure. There is a long debate about the target CSF drainage pressure and level of transducer. This was nearly solved to be 10 mm Hg rather than 15 mm Hg. [Anesth Analg 2010;111:46 –58] Again, Norris EJ in the Miller’s Anesthesia Textbook, 2009 mentioned that: – paraplegia is a devastating complication of aortic surgery. The incidence of paraplegia is reported to be 0.5% to 1.5% for coarctation repair, 0% to 10% for thoracic aneurysm repair, 10% to 20% for thoracoabdominal repair, and as high as 40% for extensive dissecting TAA repair. -Any of the various methods of distal bypass are likely to be beneficial when the anticipated cross-clamp time islonger than 30 minutes, but they are probably not beneficial when cross-clamp time is less than 20 minutes. -Although CSF drainage is widely used during TAA repair, the technique is not without risks. Potential complications include headache, meningitis, chronic CSF leakage, spinal or epidural hematoma, and subdural hematoma. [Anesth Analg 2010;111:46 –58, J Cardiothorac Vasc Anesth 1995; 9(6): 734-747, J Cardiothorac Vasc Anesth 2005; 19(3): 392-399] A recent retrospective review of 230 patients who underwent TAA repair with CSF drainage at the Johns Hopkins Hospital reported eight subdural hematomas (3.5%). [J Vasc Surg 2002; 36:47-50.] -Hypothermia is probably the most reliable method of neuroprotection from ischemic injury. By reducing oxygen requirements by approximately 5% for each degree centigrade, a twofold prolongation of tolerated cross-clamp time is achieved by cooling even to mild hypothermia (34°C). [Also, Augoustides JG, Pantin EJ and Cheung AT wrote the same] I used passive hypothermia to 34 C during the present case. Estrera et al considered the following cases as exclusion from the use of CSF drainage; the cases with rupture, acute trauma, infection, or prior paraplegia. [Ann Thorac Surg. 2009 Jul;88(1):9-15; discussion 15.]. In the present case, i had an emergent traumatic aortic transection with expected short calmping time, so i found CSF drainage would be not cost-effective.