Best practices for Red Blood Cell Exchange procedures on the Spectra Optia apheresis system to treat Sickle Cell Disease patients
Bridget Hughes - Nurse Practitioner Therapeutic Apheresis Services Leeds 2017 Content
• Procedure management • Custom prime • Depletion/ exchange procedures NICE Guidelines And then... Procedure Management FCR, replacement fluid volume, target HCT, target fluid balance, replacement fluid HCT Red Blood Cell Exchange
• Known as automated exchange or exchange- transfusion • Defective RBC are removed and normal RBC are simultaneously infused • Can rapidly adjust the HCT% and HbS% concentration of the patient • Avoids fluid overload, increased viscosity and iron overload associated with transfusions Defective red cells removed
Blood Donor red cells warmer infused
Blood pumps Patient Information • Sex • Height Total blood volume • Weight • HCT% Patients who are <25 kg require a manual calculation of the TBV Procedural Parameters to Order • Pre/ target HBS% or FCR
• Final (desired) patient HCT%
• Fluid balance
• The replacement fluid HCT%
• The final (post-procedure) patient HCT% Final HCT- Iron Overload • Every unit of packed RBC contains approximately 200mg heme iron
• Every increase of 3 points in the patient’s final HCT% = 1 additional unit of RBC transfused to the patient
• The transfusion of as few as 10 to 20 RBC units can cause iron overload
• RBCX avoids iron overload by balancing the removed RBC with the infused RBC ie it is iron neutral Final HCT- Other Factors • Blood viscosity • Blood Usage FCR% V HbS% V Replacement Fluid Volume
• The Spectra Optia system operator needs to know one of the following data points: – FCR% – Patient’s current HbS% and desired final HbS% – Replacement fluid volume of RBC Which one to use and when? What is Fraction of Cells Remaining (FCR%)?
The percentage of the original RBC remaining in the patient’s body at the end of the procedure
Patient RBC RBCX Donor RBC
A lower FCR results in a lower final HbS% and a FCR greater volume of RBC exchanged Relationship between FCR% and HBS%
Post HbS% = FCR% Pre HbS%
10% = 25% 40% 40% 10% Starting HbS Desired HbS (Pre Procedure) (Post Procedure) Pre + Post procedure HBS% • It is generally accepted that the pre-procedure HbS% (+HbC%) should be maintained at or below 30% to minimise morbidity and mortality associated with SCD Fluid Balance
• Fluid balance during an RBCX procedure is generally set at 100% (isovolemic) ; if that is the case, isovolemia is maintained throughout the procedure • The Spectra Optia system also allows the operator to run the procedure with a positive (>100%) or negative (<100%) fluid balance if required by the ordering physician Custom Prime Albumin or RBC Custom Prime
• Custom prime consists of replacing the normal saline (NS) used to prime the device with either RBC, 5% albumin or plasma • It is an option to be used whenever the extracorporeal volume (ECV) of the apheresis device exceeds a pre-set maximum percentage of the patient’s TBV • Used in paediatrics <25kg Exchange Depletion Procedure, protocol, efficiency Protocol • Phase 1: Isovolemic Depletion • Phase 2: Exchange • The overall result is a more efficient procedure, where fewer RBC are needed to reach the same end points Efficiency Lower FCR (final HbS%) The same volume of blood is used Lower FCR attained
Fewer RBC required Same FCR targeted 1 unit less RBC needed RCX Programme at Leeds
• 9 Adults & 9 Paediatrics – 5-7 weekly – Attend the unit for procedure, Leeds Children’s Hospital or Hull – Attend 2 days pre RBCX for cross matching – Memos sent out in advance – 4 require CVC insertion, we have 1 patient with a vortex port and all others including the children have peripheral access – In the process of training to Deep Vein Cannulate those that currently have regular line insertions – Ages 5-45
• Performed over 20 Acute RCX last year Lovely Laura at Paediatric RCX Clinic Thank you for listening
Any questions?