Combined hemodilution and hypotension monitored with jugular bulb oxygen saturation, EEG, and ECG decreases transfusion volume and length of ICU stay for major orthopedic surgery

Study Objective: To assess the efficacy and safety of hemodilution combined with induced hypotension during surgery. Design: Randomized, nonblinded, controlled study. Setting: Operating room suite and intensive care unit (ICU) at a university hospital. Patients: 16 ASA physical status I and H patients who underwent general or general plus epidural anesthesia for major orthopedic surgery. Interventions: In Group 1 (n = 10), mean arterial blood pressure (MAP) was decreased to 50 mmHg by increasing the inspired concentration of isoflurane and injecting 75 mg of 0.5% bupivacaine into the epidural catheter. Hematocrit was decreased to 20% by phlebotomy and simultaneous infusion of crystalloid and colloid. In Group 2 (n = 6), isoflurane was adjusted to maintain MAP within 20% of baseline values, and no phlebotomy or hemodilution was used. Measurements and Main Results: Efficacy of hemodilution combined with induced hypotension (Group 1) was compared to standard management of blood volume and pressure (Group 2) by measuring transfusion volume and length of ICU stay. Safety of hemodilution/hypotension was determined by measuring the electroencephalogram, internal jugular venous oxygen saturation, the electrocardiogram, and central venous oxygen saturation. In Group 1, both the volume of homologous blood (225 ± 150 ml) and total blood (1440 ± 286 ml) was significantly less than the volume of homologous blood transfused in Group 2 (2650 ± 878 ml). No patients in Group 1, but all patients in Group 2 required ICU admission (3.5 ± 1.6 days) for treatment to prevent sequelae from or progression of, moderate-severe tissue edema and metabolic acidosis. Cerebral and myocardial measures were not significantly different between groups. Conclusions: Hemodilution combined with induced hypotension was safe and may reduce the need for transfusion and ICU admission.