Ruyter, Martin L. De

Background Paraplegia is a devastating complication for patients undergoing repair of thoracoabdominal aortic aneurysms. A monitor to detect spinal cord ischemia is necessary if anesthesiologists are to intervene to protect the spinal cord during aortic aneurysm clamping. Methods The medical records of 60 patients who underwent thoracoabdominal aortic aneurysm repair with regional lumbar epidural cooling with evoked potential monitoring were reviewed. The authors analyzed latency and amplitude of motor evoked potentials, somatosensory evoked potentials, and H reflexes before cooling and clamping, after cooling and before clamping, during clamping, and after release of aortic cross clamp. Results Twenty minutes after the aortic cross clamp was placed, motor evoked potentials had 88% sensitivity and 65% specificity in predicting spinal cord ischemia. The negative predictive value of motor evoked potentials at 20 min after aortic cross clamping was 96%. Conclusions Rapid loss of motor evoked potentials or H reflexes after application of the aortic cross clamp identifies a subgroup of patients who are at high risk of developing spinal cord ischemia and in whom aggressive anesthetic and surgical interventions may be justified.

Paraplegia is a major complication associated with repair of thoracoabdominal aortic aneurysms (TAAA). A number of therapies have been tried over the years, none of which has been successful. Recently, regional lumbar epidural cooling has been tried in an attempt to prolong the safe ischemic time during aortic cross- clamping. In approximately 90 patients in whom the authors have tried this technique, there was no de crease in the incidence of paraplegia in patients with type II TAAAs. This is perhaps not unanticipated be cause the paraplegia is related to a number of factors including the duration of the aortic cross-clamping, the adequacy of collateral circulation, embolization during the procedure, and perhaps thrombosis in situ. Given the multimodal cause of paraplegia, perhaps it is naive to think that a single therapy would be of benefit. Additional studies are necessary to explore the mecha nisms and to prove efficacy or lack of benefit of any techniques designed to decrease the incidence of paraplegia in patients undergoing TAAA repair.

The postoperative care of a patient who receives an intra-abdominal organ transplant is in some ways simi lar to that of any major intra-abdominal procedure. However, certain features unique to organ transplanta tion, such as the variable functional status of the newly transplanted graft, complications that are specific to the organ transplanted, and the side effects from immuno suppressive drugs, suggest that transplantation inten sive care is a distinct subspecialty in critical care medicine. Today, the majority of patients receiving an intra-abdominal transplant will have a relatively uncom plicated postoperative course. However, preoperative disposition, intraoperative misadventure, or immediate postoperative difficulty will require the availability of an intensivist experienced in transplantation. The future of intra-abdominal transplantation will be highly depen dent on progress in immunotherapy. Newer, more spe cific immunomodulators with fewer nonimmune toxici ties should result in improved organ receptance, less graft dysfunction, and improved patient survival.