Intraoperative Cell Salvage and Hemodilution Technique in Scoliosis Surgery
Intraoperative Cell Salvage and Hemodilution Technique in Scoliosis Surgery
Surgical correction of scoliosis with instrumentation carries significant blood loss and
 needs for blood transfusion with its inherent risk and cost. In recent years, there is an
 increased interest in utilizing autologous blood as part of perioperative blood conservation
 strategy.

 The foremost mechanical methods of perioperative conservation of red blood cells including
 intraoperative cell salvage (ICS) and acute normovolemic hemodilution (ANH). They should be
 considered in all cases where significant blood loss (>1000 ml) or >20% estimated blood
 volume is expected, in patients with multiple antibodies or rare blood types and those who
 refuse allogenic blood products.

 Literature search has revealed that both cell salvage method and ANH utilized in elective
 surgeries are capable of minimizing allogenic blood transfusion respectively. Surgeries which
 are of significant relevance are aortic surgery, cardiac surgery and arthroplasty orthopaedic
 surgery. Combining the above two techniques such as in ATIS trial 2002 also shows that it is
 safe and significantly reduced allogenic blood requirements in aortic surgery. However till
 date, there is still lack of strong evidence that autologous blood transfusion technique is
 beneficial for scoliosis surgery in reducing allogenic blood transfusion.

 Hypothesis:

 The investigators hypothesize that the addition of ANH to ICS would confer additional benefit
 than using cell saver alone. By combining cell saver with hemodilution technique, the
 difference between pre-operative and post-operative Hemoglobin level will be smaller than
 using cell saver technique alone, hence minimizing the variation in perioperative Hemoglobin
 level - a predictor of allogenic blood transfusion.
Patients who meet the inclusion criteria are enrolled in the study. They are assigned to 2
 arms of study group using concealed allocation method. A computerized random-number generator
 will be used to formulate an allocation schedule. Group A will receive cell salvage and acute
 normovolemic hemodilution during operation; Group B will only receive cell salvage as sole
 autologous transfusion strategy.

 Members of the research team should attend all operations and record all data. Anaesthetic
 technique including drugs usage, equipments and monitoring devices are standardized as per
 protocol. Intraoperative fluid management is recorded in details.

 All patients enrolled in the study (group A and B) underwent cell saver technique during
 surgery using Cell Saver® 5+ autologous blood recovery system-Haemonetics devices. All
 patients allocated in group A also received additional acute normovolemic hemodilution (ANH)
 after induction of anaesthesia. As a standardization measure, before starting skin incision,
 500ml blood will be collected from the radial artery to a standard blood collection bag and
 stored as CPD blood at ambient temperature. Simultaneously, 500ml Voluven® (6% hydroxyethyl
 starch 130/0.4 in 0.9% sodium chloride) will be infused through a peripheral vein.

 All autologous blood will be re-infused back to patient at surgery completion or within 6
 hours of withdrawal. Autologous blood will be given to patient during surgery at any point if
 there are 30% or more body blood volume loss.

 Allogenic blood will be administered when the intraoperative hemoglobin concentration fell
 below 8g/dl despite completion of autologous blood transfusion or when autologous blood not
 available; adequate volume correction by mean of collected autologous blood and crystalloid
 fluid administration, or when presence of ischemic electrocardiogram changes (2mV ST segment
 elevation or depression on 3 leads monitoring); persistent hypotension or tachycardia >20%
 from baseline.
Inclusion Criteria:

 -  Elective single stage posterior spinal fusion for scoliosis corrective surgery

 -  Diagnosis of idiopathic scoliosis

 -  Age >10 and <25

 -  ASA I or II

 -  Preoperative Hemoglobin > 10 g/dL

 -  Preoperative Platelet > 150,000/L

 -  Clinically fit for surgery

 -  Written informed consent

 Exclusion Criteria:

 -  Patient's refusal of homologous blood

 -  Hematological disorder rendering either transfusion technique inappropriate

 -  Patients who received anticoagulants and antiplatelets perioperatively

 -  Severe cardiac disease (Aortic stenosis or cardiac ejection fraction <40%; Myocardial
 infarction in the previous 6 Months; Myocardial ischaemia on resting
 Electrocardiogram)

 -  Severe pulmonary disease (FEV1 50% predicted, PaO2 9 kpa on air)

 -  Preoperative creatinine >200 mmol/L

 -  AST >100 IU/L