Cost Effectiveness and Clinical Utility of Cell Saver Use for Two to Three Level Lumbar Fusions

INTRODUCTION:

Cell Savers are used intraoperatively to decrease the risk of transfusion due to surgical
blood loss. Blood collected from the operative field is anticoagulated, filtered, and stored
in a reservoir. Once a set volume of blood has been collected in the reservoir, the blood is
separated into its red blood cell and plasma components by use of a centrifuge. Red blood
cells are washed with a crystalloid solution and then reinfused into the patient. Although
the theoretical benefits of using a cell saver are attractive, the literature seems to be
controversial with respect to efficacy and cost-effectiveness. The benefits are clear in
patients undergoing fusions for scoliosis that involve more than 5 levels where blood loss
is considered substantial. It is less clear in patients who undergo a more limited two to
three level lumbar fusion.

The purpose of this study is to determine the cost-effectiveness of using a cell saver for 2
to 3 level lumbar fusions. A secondary objective is to determine if there will be a decrease
in the number of allogenic blood transfusions when a cell saver is used intraoperatively.
Another secondary objective is to determine incidence of complications associated with cell
saver use and transfusions.

METHODS Patients seen at the Norton Leatherman Spine Center scheduled to have decompression
and fusion over 2 to 3 lumbar spine segments will be screened for the study. After obtaining
informed consent, patients will be randomized to have a cell saver used intraoperatively
(Cell Saver group) or no cell saver (Non-Cell Saver group). Data to be collected will
include age, gender, smoking status, height, weight, co-morbidities, the use of medications
that may increase bleeding (Plavix, Coumadin, Warfarin), or increase blood production
(Ferrous sulfate, erythropoietin) medications used to decrease intraoperative bleeding
(Aprotinin, Tranexamic Acid); the use of hypotensive anesthesia, ASA Grade, indications for
surgery, date of surgery, estimated blood loss, surgical approach, surgical levels, bone
graft used, operative time, complications, length of stay, discharge information, whether or
not patient pre-donated blood, hemoglobin, hematocrit and maximum body temperature prior to
surgery and during the patient's hospital stay, surgical drain output, products transfused
intraoperatively and postoperatively and the amount of cell saver salvaged, re-infused, and
the cell-saver hematocrit and hemoglobin prior to re-infusion. The costs associated with the
use of the cell-saver and/or blood transfusions, including supplies and personnel time, will
be determined.

Randomization Randomization will be through stratified block randomization to allow for
stratification of the number of levels fused. Randomization will use sealed envelopes.

Sample Size To detect a medium effect size of 0.3 with an α error of 0.05, a total of 220
subjects need to be included in the analysis. To account for subject withdrawal, a total of
240 subjects will be enrolled

Procedures Patients receiving care at the Norton Leatherman Spine Center will be screened as
potential subjects for the study. Only the existing information obtained per standard
routine medical procedures will be used. Patients who fail pre-screening will not be
recorded on any log or form. Patients considered potential candidates for the study based on
screening will sign an Institutional Review Board -approved Informed Consent Document and
HIPAA Authorization form prior to participating in any study activity.

Subjects will be randomized to receive or not receive cell saver during surgery. The
following data will be collected during the clinic visit: age, gender, smoking status,
height, weight, co-morbidities, the use of medications that may increase bleeding (Plavix,
Coumadin, Warfarin), or increase blood production (Ferrous sulfate, erythropoietin). The
following pre-operative data will be collected: hemoglobin, hematocrit, body temperature and
whether or not patient pre-donated blood, the predonated blood volume and date of donation.

Surgery will be performed per the standard of care of the treating surgeon. The choice of
surgical approach, instrumentation and bone grafts/bone graft substitutes will be at the
discretion of the surgeon. The following intraoperative data will be collected: use of
hypotensive anesthesia, ASA Grade, indications for surgery, date of surgery, estimated blood
loss, surgical approach, surgical levels, bone graft used, operative time products
transfused intraoperatively. In the subjects randomized to the Cell Saver group, the amount
of cell saver salvaged, re-infused, and the cell-saver hematocrit and hemoglobin prior to
re-infusion will be determined and collected. In-hospital post-operative data to be
collected include: complications, length of stay, discharge information, hematocrit,
hemoglobin and maximum body temperature during the patient's hospital stay, surgical drain
output, products transfused postoperatively.

Subjects will be transfused at a set transfusion threshold of hemoglobin of 7.0g/dL or below
and corresponding hematocrit of 21 or below. Subjects with Hb 7.0g/dL and are symptomatic as
evidenced by tachycardia, hypotension, orthostatic hypotension or have pre-existing cardiac
or pulmonary disease will also be transfused.

The risks that occur in this study are associated with the general risks of spine surgery.
Risks associated with allogeneic blood transfusion include allergic reactions, hemolytic
reactions, isoimmunization, graft versus host reactions, increased infection rates, and
transmission of bloodborne pathogens, including human immunodeficiency virus and hepatitis.
Risks associated with the use of a cell saver include a paradoxical increase in blood loss,
electrolyte depletion, metabolic acidosis, and hematuria

Endpoints The primary endpoint is the volume of blood transfusion required. Secondary
endpoints include

- Immediate post-op Hematocrit level

- Immediate post-op Hemoglobin level

- Volume of blood products used post-operatively

Statistical Analysis Descriptive statistics, including frequency counts for discrete
variables and measures of central tendency (means, medians) and dispersion (standard
deviation, range) for continuous variables will be calculated. Comparisons between the Cell
Saver and non-Cell Saver groups will be done with independent t test for continuous
variables and χ2 tests for discrete variables. To determine the effects of potentially
confounding variables, analysis of covariance to compare the Cell Saver and non-Cell Saver
groups will be used. This will help identify variables that may be statistically different
between the Cell Saver and non-Cell Saver groups that could potentially influence the total
units of blood transfused. Those variables that were significantly related (i.e.,
correlated) with the number of units of blood transfused will be entered as covariates into
the statistical model to determine if they affect the statistical conclusions between the
Cell Saver and non-Cell Saver groups. All analyses will performed an a priori alpha level of
0.05 using IBM SPSS version 19.0.

Funding This study will be unfunded.

Inclusion Criteria:

- At least 18 years of age at time of enrollment

- Signed informed consent

- Requires fusion of 2 to 3 levels from L1-S1 for degenerative lumbar disorders

Exclusion Criteria:

- Spinal trauma/fracture/malignancy

- Infection as an indication for surgery

- Pregnant or nursing women

- Prisoners

- Institutionalized in a non-voluntary and/or dependent residence (including hospitals,
group homes, etc.), who may not be competent to give informed consent.

- Inability to speak or understand English