RESUMO
Guidelines do not include cerebral oximetry among monitoring for carotid endarterectomy (CEA). The purpose of this study was to evaluate the reliability of near-infrared spectroscopy (NIRS) in the detection of clamping ischemia and in the prevention of clamping-related neurologic deficits using, as a cutoff for shunting, a 20% regional cerebral oxygen saturation (rSO(2)) decrease if persistent more than 4 minutes, otherwise a 25% rSO(2) decrease. Bilateral rSO(2) was monitored continuously in patients undergoing CEA under general anesthesia (GA). Data was recorded after clamping, declamping, during shunting and lowest values achieved. Preoperative neurologic, CT-scan, and vascular lesions were recorded. We reviewed 473 cases: 305 males (64.5%) mean age 73.3 ± 7.3. Three patients presented transient ischemic deficits at awakening, no perioperative stroke or death; 41 (8.7%) required shunting: 30 based on the initial rSO(2) value and 11 due to a decrease during surgery. Using the ROC curve analysis we found, for a >25% reduction from baseline value, a sensitivity of 100% and a specificity of 90.6%. Reliability, PPV, and NPV were 95.38%, 9%, and 100%, respectively. In conclusion, this study indicates the potential reliability of NIRS monitoring during CEA under GA, using a cutoff of 25% or a cutoff of 20% for prolonged hypoperfusion.
RESUMO
OBJECTIVES: Spinal cord stimulation (SCS) was proposed many years ago for pain treatment but healing of ischemic ulcers opened a new treatment indication. The aim of this review was to assess the efficacy of SCS. METHODS: studies regarding ischemic pain, limb ischemia and SCS reported on Pubmed have been reviewed, including randomized controlled trials (RCTs), clinical trials, Cochrane library review, neurophysiological studies and microcirculatory evaluations. RESULTS: Five RCTs, three multicenter studies and many clinical trials and reports of series have documented the clinical efficacy of SCS in the treatment of ischemic pain, particularly in patients with post-implantation increased blood flow. Pain relief, ulcer healing and limb salvage seems to be greater in non-diabetic patients, in diabetic without autonomic neuropathy, and in patients with rest pain or ulcer more than in patients with gangrene. A pain reduction of 75% was reported in the 3 RCTs; pain relief was significantly greater than in control group. Another study reported a lower use of analgesic in the SCS group. Moreover, pain relief obtained with SCS is maintained at follow-up while relief after medical treatment disappears quickly. The three multicenter studies showed a total pain relief between 41% and 43% and a cumulative pain reduction of 75% in 64.8% of cases. The clinical trials reported a pain reduction in up to 91% of patients. Based on six studies, the Cochrane reviewers found evidence to favor SCS over standard conservative treatment to improve limb salvage and clinical situation in patients with non-reconstructable critical limb ischemia (CLI). The mechanism of action of SCS is not completely clarified. DISCUSSION AND CONCLUSIONS: the endovascular approach reduced the number of patients unsuitable for revascularization, however, some patients cannot be treated by angioplasty or open surgery; moreover, some are unfit for surgery, and others have persistent distal ischemia and pain with a functioning revascularization. In these cases SCS (alone or associated with prostanoids) can be indicated on the basis of the more recent evidences. A trial period with external stimulator, associated with a microcirculatory evaluation, is currently utilized to select patients that can derive benefit from this treatment, reducing costs.