4. On Assembling and Priming

Assembling

You should always know what is principal and what is secondary. Principal is main pump. That is why pump boot should be assembled first. Principal is gas supply.

It's not fair to skip checking occlusion only because you don't know how to do it.

Bubble detector

Priming

It's useful to put arterial filter upside down when recirculating.

FFP Usage Per Kilogram Weight:

> 10 Kg = No FFP used

< 10 Kg = Ѕ unit of FFP, Unless Fresh Whole Blood is used

< 5 Kg = 1 unit of FFP or Ѕ unit of FFP with Fresh Whole Blood

Это Dick S. De Jong в 2001 году разгромил растворы крахмалов за гипокоагуляцию!

Do not be afraid of recirculating. Anyway, perfusion is an
area laying far from high pressure industry.

Packed red cells if haematocrit predicted on bypass below 27%.

Packed Red Cells: Volume of packed red cells is based on the following formula:-
mls of PRCs = [(patient volaemia + prime vol.) x Hct. desired] - (patient volaemia x patient Hct)

The haematocrit of Packed Red Cells is assumed to be 70%.

When packed red cells are added to the pump prime, pre-bypass ultrafiltration is employed. Fluid loss from the circuit is balanced with lasmalyte A (or comparable crystalloid solution) and buffered with Sodium Bicarbonate prior to the initiation of CPB. The amount of fluid removed during PBUF should be above 3ml per ml of packed red cells used.

Red Blood Cells: 

PRBC used in the prime of pediatric circuits to reach a desired on CPB hematocrit of 25 – 35% based on the type of surgical procedure and also the congenital anomaly present. 

Heparin = 1 KIU Heparin up to 10 Kg. then +100 IU/kg added

ATIII

units required(IU)= (desired - baseline ATIII level) X kg/ 1.4

Lasix = 0.25mg / Kg

Solumedrol = 30 mg/ Kg

Open peel packs to scrub nurse


spike line

vacuum-relief valve on vent

Sarns 7000 - belt, Sarns 9000 - electromagnetic.

arterial filter priming is crucial - labyrinths

Mannitol is used as a drug since 1962.

Mannitol - PGE2

Hypotension after mannitol lasts not more than 5 minutes.

power supply failure

If blood products are used during priming, start bypass after performing air purge thoroughly.

Excessive hemodilution reduces oxygen delivery, and hemoglobin concentrations below 8g/L cause organ dysfunction at temperatures above 30°C.

In prolonged complicated perfusions the interstitial compartment may increase 18% to 33%, but intracellular water does not increase during CPB.

Priming solution should be not only isotonic, but also physiologically balanced with patients blood.

Normal Saline can be used to mix drugs, but should never be considered as a priming solution.

Plasmalyte A and Normosol are the routinely accepted priming soluitons.

CO₂ flushing of the CPB circuit has been done for years to help prime the circuit by replacing room air nitrogen (which doesn't go into solution) with CO₂ which is more difusable into solution. With the advent of coated circuits, it has become more easy to prime circuits, but you still need to CO₂ flush first. The technique does require you to help the CO₂ to get into the right area's of the circuit by placing clamps at strategic places on your tubing eg., arterial filter and oxygenator bundle. 

Important Points / Tips

Less than 10 kg - roller pump, or hard to wean.

Rule of thumb for occlusion

3/8 - 1cm/min

1/4 - 2cm/min

Boot loop should not cross the mast.

Silicone tubing has memory.