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 ApheresisServices Leeds2017

Content

• Procedure management

• Custom prime

• Depletion/ exchange procedures

NICE Guidelines

And then...

Procedure ManagementFCR, 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 warmer

Blood pumps

Donor red cells infused

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%)?

Patient RBC

FCR

Donor RBCRBCX

The percentage of the original RBC remaining in the patient’s body at the end of the procedure

A lower FCR results in a lower final

HbS% and a greater

volume of RBC

exchanged

Relationship between FCR% and HBS%

Starting HbS(Pre Procedure)

Desired HbS(Post Procedure)

40% 10%

Post HbS%

Pre HbS%=

10%40%

25%

FCR%

=

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 PrimeAlbumin 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 DepletionProcedure, 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 Hos pital 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 v ortex port

and all others including the children have peripher al access– In the process of training to Deep Vein Cannulate th ose 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?