Near infrared spectroscopy monitoring during carotid endarterectomy: which threshold value is critical?

OBJECTIVES: Retrospectively to verify which decreasing percentage in regional oxygen saturation (rSO(2)) identified patients with good collateralisation during carotid artery cross clamp. MATERIALS AND METHODS: During 594 endarterectomies under general anaesthesia the decreasing percentage from preclamp value to value detected in the first 2 min after clamping the CCA and/or ICA was calculated in real time. No temporary shunt was placed in any case. ROC analysis was performed to determine the optimal cut-off for rSO(2) decrease to identify the occurrence of neurological complications. RESULTS: A cut-off of 11.7% was identified as optimal. Sensitivity and specificity were 75% (95% CI 71-78) and 77% (95% CI 74-80), respectively. The cut-off of 20% had a lower sensitivity (30%) and a higher specificity (98%) to identify patients with complications, with positive and negative predictive value of 37 and 98%, respectively. CONCLUSIONS: The study suggest that a relative decrease in rSO(2) of <20% from preclamp to early cross clamp value has a high negative predictive value, i.e. if rSO(2) does non decrease more than 20%, ischemia by hypoperfusion is unlikely and a shunt should not be necessary. Moreover, a relative decrease >20% may not always indicate intraoperative neurological complications.

[Experimental kidney transplantation: a comparison between different models]. / Trapianto di rene sperimentale nel suino. Modelli a confronto.

AIM: Two different models of kidney transplantation have been compared using 3 different techniques. The kidney grafts were procured from living donors (laparoscopic or laparotomic technique) and from cadaveric donors. METHODS: Twenty-four outbred piglets (Large White, weight range 24-27 kg) underwent kidney transplantation. We divided the recipients into 2 groups with the following characteristics: group 1 (n=12) was represented by orthopic kidney recipients whose grafts were retrieved by laparoscopic or lapartomic technique from living unrelated donors; group 2 (n=12) was constituted by heterotopic kidney recipients whose grafts were retrieved by laparotomic technique from unrelated cadaveric donors. In both groups, Grogoire-Lich technique and Politano-Laedbetter technique were used in order to perform ureteral-vescical anastomosis together with a new technique developed from our experience called Politano-Laedbetter modified. All transplanted pigs underwent double immunosoppressive steroid therapy (tacrolimus and micofenolate mofetil). The pigs were observed for 60 days. RESULTS: The survival rates in group 1 and in group 2 were 75% (n=9) and 66% (n=8), respectively. No significative differences were noted in length of operative time, creatinemia and ureamia levels in both study groups. The Gregoire-Lich technique was associated with a higher rate of complications. CONCLUSION: Two different experimental models of kidney transplantation are feasible in pigs. The classic technique could be combined with the orthopic one based on the type of study needed.