For our study, the estimated nadir THI for 100% blood volume reduction (THI100) was estimated from the nadir THI measured during exsanguination (THI69), having an assumed 69% volume reduction in blood. With THI prior worldwide distributors to exsanguination (THI0) measured, the following equation was used to calculate THI100:Heart rate and blood pressure were recorded before the and THI monitoring period. Collected demographic StO2 information included gender, age, ethnic group, height, weight, and hand dominance.Porcine hind limb: blood hemoglobin dilutionThe University of Minnesota Animal Use Committee, in accordance with established guidelines for the treatment of laboratory animals, approved this study of five male pigs weighing 18 to 28 kg each. Prior to anesthesia induction, a subcutaneous tissue depth ��1.

5 mm was verified with a skinfold caliper. Intramuscular ketamine 20 mg/kg and intravenous propofol 2 to 6 mg/kg were used to induce anesthesia. After intubation, anesthesia was maintained with 60% inhaled nitrous oxide and continued administration of propofol. One dose of intravenous heparin 100 units/kg was given, administered after surgery.An InSpectra? optical sensor was applied to the mid medial thigh of both hind limbs. A pulmonary artery catheter was placed via the internal jugular vein and an arterial line was placed into the carotid artery. During laparotomy, a splenectomy was performed and the distal aorta and vena cava were surgically accessed to facilitate cross-clamping to create acute hind limb ischemia.

The femoral artery and vein of the right hind limb were accessed and fitted with annular ultrasonic flow transducers (Model TS420; Transonic Systems, Inc., Ithaca, NY, USA).The total blood hemoglobin concentration was lowered by removing blood from the pulmonary artery catheter and replenishing the shed blood with Hextend? (Hospira, Inc., Lake Forest, IL, Brefeldin_A USA) to achieve targeted systemic hemoglobin levels of 13 g/dl, 10 g/dl, 7 g/dl, and 4 g/dl. A 20 mg bolus of furosemide was used to hemoconcentrate three of the five animals to elevate the baseline Hbt level to approximately 13 g/dl. To achieve 0.5 g/dl Hbt measured in the right femoral vein, the distal aorta was clamped and Hextend? was perfused below the cross-clamp site. The right femoral vein was incised to facilitate syringe sampling of the diluted blood effluent. After each targeted systemic Hbt level had been achieved, the StO2 THI, cardiac output, femoral artery and venous blood flows, blood pressures, temperature, pH, blood gases, oxygen saturation, lactate, hemoglobin, and base excess measurements were collected. StO2 and THI were subsequently measured during replicate aorta and vena cava 3-minute cross-clamp occlusions. StO2 and THI were recorded continuously.