Intraoperative cell salvage using swab wash and serial thromboelastography in elective abdominal aortic aneurysm surgery involving massive blood loss.

The loss of 50% blood volume is one accepted definition of massive haemorrhage, which ordinarily would trigger the massive transfusion protocol, involving the administration of high ratios of fresh frozen plasma and platelets to allogeneic red cells. We investigated 53 patients who experienced >50% blood loss during open elective abdominal aortic aneurysm surgery to assess allogeneic blood component usage and coagulopathy. Specialist patient blood management practitioners used a tailored cell salvage technique including swab wash to maximise blood return. We assessed the proportion of patients who did not require allogeneic blood components and develop evidence of coagulopathy by thromboelastography (TEG) parameters. Blood loss was 50%-174% (mean [SD] 68% [27%]) of blood volume. The mean (SD) intraoperative decrease in haemoglobin concentration, assessed by arterial blood gas analysis, was 5 (13) g/l. No patient received allogeneic red cells intraoperatively. Four of the 53 (8%) patients received blood components in the first 24 h postoperatively at the anaesthetists' discretion. No patient had intraoperative TEG changes indicative of fibrinolysis or coagulopathy. The 30-day mortality was 2% (one of 53). Reduction of allogeneic transfusion is one aim of patient blood management techniques. We have demonstrated virtual avoidance of allogeneic blood product transfusion despite massive blood loss. These data show possible alternatives to the current massive transfusion protocols to the management of elective vascular surgical patients.

Regional anesthesia for vascular surgery.

Vascular surgical patients are a diverse group of patients who tend to be elderly, with multiple comorbidities, while vascular procedures may involve significant blood loss and ischemia of tissues beyond the arterial obstruction. Regional anesthesia techniques may offer benefits to patients undergoing vascular surgery because of their cardiorespiratory comorbidities. However, this group of patients is commonly receiving multiple medications, including anticoagulants, so regional techniques are not without risks. This review will discuss this topic based around 3 fundamental revascularization procedures, carotid, abdominal aortic aneurysm repair, and infrainguinal surgery, discussing the clinical applications of regional techniques relevant to each key area.

Increased oxygen administration improves cerebral oxygenation in patients undergoing awake carotid surgery.

BACKGROUND: During regional anesthesia for carotid endarterectomy (CEA), 10% to 15% of patients develop signs of cerebral hypoxia after cross-clamping, manifested as changes in speech, cerebration or contralateral motor power. Reversal of such neurological deficits using administration of 100% O2 has been described. We used near-infrared cerebral oximetry to assess whether 100% O2 reliably improves regional cerebral oxygenation (rSO2) during carotid cross-clamping. METHODS: Sixteen patients undergoing awake CEA were studied. Bilateral rSO2 optodes were applied before the initiation of sedation and the conduct of the regional blockade. Patients received 28% oxygen by Venturi facemask. Perioperative blood pressure was maintained at or within 10% above the patient's normal limits during carotid cross-clamping. After cross-clamping, 100% O2 was administered for 5 min by a close-fitting anesthetic facemask. The O2 mask was then removed and the patient breathed room air. The effects on rSO2 readings and arterial blood gases were observed after each intervention. RESULTS: Data were analyzed for 15 patients. Ipsilateral rSO2 values decreased by 7.4% +/- 5% after carotid cross-clamping. Administration of 100% O2 resulted in an increase in ipsilateral rSO2 in all patients of 6.9% +/- 3.3% (range, 1%-12%) (paired t-test, P < 0.001) over the cross-clamped value while receiving 28% O2. Hemodynamic variables and arterial PaCO2 values were unaltered. CONCLUSION: With the carotid cross-clamped, ipsilateral rSO2 was reliably increased by the administration of 100% O(2) compared with 28% O2. The etiology of this increase is unclear, but may relate to the associated increase in O2 content of the blood or to an improvement in cerebral blood flow. Thus administration of 100% O2 during carotid cross-clamping may be beneficial for all patients undergoing CEA.