Question

A blood transfusion is being set up in an emergency room for an accident victim. Blood has a density of1060 kg/m³ and a viscosity of 4.0

Answer 1

Answer:

The idea here is to assume Poiseulle flow, so that the relation between pressure differential ?p, flow rate Q, radius of the circular cross section R, length of the needle L and viscosity ? is

Q = ? ?p R? / ( 8 ? L)

Solving for pressure differential this gives

?p = 8 ? L Q / (? R?).

But in the hydrostatic case ( valid here for slow flow) we know


?p = ? g ?h

Therefore


?h = 8 ? L Q / (? g ? R?).

With the give data this calculates to

?h = 8* 4.0*10^-3 kg/(m s) * 0.030 m * 4.4*10^-8 m^3/s /( 1060kg/m^3 * 9.81m/s^2*3.1415*(25*10^-5 m)^4)
= 33cm

Extra points:

Requirements for setting up a Blood Transfusion

• Ensure that the Record of Transfusion form and prescription (fluid chart) are appropriately completed with all required signatures. On the Record of Transfusion form, Sections A, B, C and D MUST be completed before starting the transfusion.
• Secure venous access device of suitable gauge for the desired rate of
  transfusion
• Observation recording sheet (The Record of Transfusion form)
  
• Disposable gloves - for attaching administration set to patient's venous
  access and for handling blood component
  

References: http://www.shb.scot.nhs.uk/board/policies/BloodTransfusionProcedures.pdf