Priming solutions in cardiac perfusion during pulmonary bypass

This ppt highlights composition of priming solutions used during cardiopulmonary bypass surgery

1. DRUGS/FLUIDS ADDED TO THE PUMP BY PERFUSIONIST/ANESTHETIST

2. STEPS DURING CARDIOPULMONARY BYPASS SURGERY Priming Anticoagulation of the patient Connecting pt to heart-lung machine Cardiac arrest Monitoring during surgery Weaning off bypass

3. PRIMING SOLUTIONS IN CARDIAC SURGERY Perfusionist primes the system to remove air from heart-lung machine to manage blood flow and prevent complications from embolism. Patient factors required to aid in the choice of priming solutions; Height & Weight Renal status Hb / HCT Fluid status

4. Composition of priming solutions varies based on factors such as the patient's specific needs, the surgical procedure preferences of the surgical team . An ideal priming solution should have the same tonicity, electrolyte composition and pH as Plasma. Tonicity is key to avoid RBC lysis and fluid shifts from extracellular to intracellular compartments. Crystaloids with near physiological Na conc. Are used ( 130-150mmol/l). Include; - Ringer’s Lactate ( Hartmann’s), Ringer’s, Normal Saline, Plasma- Lyte , Normosol

5. Priming solutions An ideal priming solution should have the same tonicity, electrolyte composition and pH as Plasma. Tonicity is key to avoid RBC lysis and fluid shifts from extracellular to intracellular compartments. Fluids with near physiological Na conc. Are used ( 130-150mmol/l). Include; - Ringer’s Lactate ( Hartmann’s), Ringer’s, Normal Saline, Plasma- Lyte , Normosol

6. Composition of Priming solutions 1. Crystalloid Solutions : These are electrolyte solutions made up of various salts dissolved in water. Common crystalloid solutions used in priming solutions include: Normal Saline (0.9% Sodium Chloride) : Provides sodium and chloride ions to maintain electrolyte balance. Lactated Ringer's Solution : Contains sodium, chloride, potassium, calcium, and lactate to help maintain electrolyte levels and pH balance. Hartmann's Solution : Similar to Lactated Ringer's solution, it also includes bicarbonate for pH regulation.

7. 2.Colloid Components : Colloids are larger molecules that help to maintain the viscosity of the blood and prevent excessive bleeding during surgery. Common colloid components include : Human Albumin Solution : Albumin is a protein that helps maintain oncotic pressure and fluid balance within the blood vessels. Gelatins e.g. Gelofusine , Hydroxyethyl Starch- Voluven , Haemacel : Synthetic colloid that help maintain blood volume and prevent hemodilution . They Counteract decrease in colloid oncotic pressure associated with hemodilution of albumin & plasma proteins in CPB.

8. Concerns with using colloid components Dextrans interfere with coagulability Albumin cost and availability Colloid- based prime has not shown to significantly influence clinical outcomes or hospital stay in comparison with crstalloids and given the cost implications they are nolonger widely used as priming soltns

9. 3. Electrolytes : Priming solutions include electrolytes to maintain proper ion concentrations, which are crucial for nerve and muscle function, including the heart: Sodium : Maintains fluid balance and supports nerve and muscle function. Potassium : Essential for maintaining proper heart rhythm and muscle function. Calcium : Important for blood clotting and muscle contractions. Magnesium : Supports muscle and nerve function, including heart function.

10. 4. Buffering Agents : To help maintain proper pH levels in the blood and prevent acidosis, priming solutions might include buffering agents like bicarbonate. 5. Anticoagulants : In some cases, heparin or other anticoagulants may be added to the priming solution to prevent blood clotting within the CPB circuit. 6. Oxygenation : To maintain oxygen delivery during CPB, the priming solution may be oxygenated before it enters the circuit.

11. Summary of composition of commonly used Priming solutions

12. Commonly used additives in priming slns Heparin 1000–2500 U/l of prime to ensure adequate anticoagulation Bicarbonate 25 mmol /l of prime as buff er when unbalanced priming solutions are used Mannitol Osmotic diuretic and free radical scavenger Calcium Needed if citrated blood is added to the prime to prevent chelation of calcium Steroids To attenuate systemic infl ammatory response to CPB (evidence weak)

13. Take away points Hartmann’s is the commonest priming sln Despite Dextrose 5% and DNS, being norminally isotonic they become hypotonic when glucose is metabolized they are not major constituents of primes . electrolyte levels used in priming solutions are carefully tailored to each patient's specific needs and the surgical context. The goal is to maintain the patient's physiological balance and prevent complications, such as electrolyte imbalances, that could affect cardiac function, nerve transmission, and overall cellular activities.