An Observational Prospective Study of Transfusion Requirements During Spinal Surgery for Severe Scoliosis

Data collected prior to surgery will include patients' past medical history, hemoglobin concentration, INR, MCV, gender, age and weight.

Immediately prior to surgery, but after induction of anesthesia, subjects will have another complete blood count drawn to assess preoperative hemoglobin/hematocrit concentrations. This is customarily done to establish a baseline. During surgery patient's core temperature, hemoglobin, hematocrit levels, estimated blood loss, Central Venous Pressure, blood pressure, heart rate, cell saver, the amount of irrigation fluid, colloid, crystalloid, blood and blood products will be recorded hourly throughout surgery. All of the data collection described is standard in these types of cases.

Patients will be transfused allogenic blood if hemoglobin levels fall below 8.0 g/dL or patients present with clinical signs/symptoms of hypovolemia (hypotension, tachycardia). Data collection concerning allogenic blood transfusion will include intraoperative transfusion rate, volume of transfused units per patient and transfusion index. Surgical intervention data regarding the extent of the surgical procedure will be collected: the number of curves, the curve magnitude, type of instrumentation required, the number of levels fused and the fluoroscopy time. The placement and type of wound drains and their .respective outputs will be noted. Preoperative and postoperative curve magnitude will be documented as well as instrumentation used to facilitate curve correction. The number of levels fused will be documented.

Hemoglobin and hematocrit levels will be noted at several intervals post operatively (24 hours, 48 hours and last result prior to discharge) and further transfusion requirement will be recorded. The length of Intensive Care Unit stay and the length of hospital stay will be noted. Regarding surgical procedure all patients will be operated on by the same surgical team, under standardized anesthesia, total intravenous anesthesia (TIVA), and postoperative analgesia. Data will be expressed as percentages or as a mean +/- SD. T-test analysis will be used for comparison for quantitative variables and a p value < 0.05 will be considered statistically significant