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Table 2 Advantages and disadvantages of mCPB and cCPB

From: Miniaturized cardiopulmonary bypass: the Hammersmith technique

   mCPB cCPB
Venous cannula   29 Fr OptiFlow (Sorin) 34/46 Fr 2-stage (Medtronic)
  Advantage • Multi-stage and longer length (increasing drainage and structural support in IVC) • Convenient and easy placement
• Less prone to collapse and blockage due to side holes and grooves • This type of cannulae is used in common practice
  Disadvantage • Rigid (requiring careful placement) as it extends further down the IVC • Larger – increased risk of interaction with IVC/RA wall
• 2 stage cannula less support in IVC thus more prone to collapse and decreased drainage from Hepatic veins and circulation
Venous line and drainage   3/8 inch tubing ½ inch tubing
  Advantage • Smaller, active kinetic drainage • Gravity syphon based
   • Monitored controlled drainage • Simple, standard and convenient
   • Tailored to patient specific venous collapse pressure  
  Disadvantage   • Uncontrollable
    • Not routinely monitored
VARD   Advisable to use in mCPB but not compulsory VARD is not required due to the presence of the Venous reservoir but it has been proven to be of benefit in all CPB circuits [8]. However, it is not commonly used.
  Advantage • Enhances safety • Cheaper
   • Efficient gross air removal • Simple open system
   • Active micro air removal • The reservoir filters and removes gross air easily
   • Decreases FSA versus standard filters used in CPB venous reservoir’s • Continuity
   • All air introduction into system  
  Disadvantage • Require perfusion experience • No active removal of micro-embolic air (just passive)
   • Extra Component of circuit • Venous reservoir in series (continued FSA exposure)
   • Vented blood has to be manually returned back into the systemic system • Increases FSA
Reservoir*   SSR or Midi card Venous reservoir (Sorin Evo)
  Advantage • Closed (no ‘in series’ blood-air interface- limits FSA exposure) • Open
   • Decreased damage to blood cells • Common practice
   • Optimises vent management • Venting possible
   • Midi card ‘in parallel’ automatic air removal • Low Pressure Suction and blood venting possible
   • Vented blood is automatically returned to the systemic circulation
  Disadvantage • SSR requires manual air bubble removal • ‘In series’ Blood-air interface
   • No Low Pressure Suction (an issue in cases where there are high volumes of LPS) • Damage to blood cells
   • Vented blood has to be manually returned back into the systemic circulation • Disguises poor suction/vent management
Centrifugal pump   Revolution (Stöckert, Germany) Standard roller pump
  Advantage • Non-occlusive • ½ inch silicon tubing
   • Pressure regulates • Cost-effective
   • Gross safety mechanism  
   • Less blood cell trauma  
  Disadvantage • Cost and training • Occlusive (No pressure regulation)
Heat exchanger and oxygenator   Eos (Sorin Group, Italy) Avant (Sorin Group, Italy)
  Advantage • 1.1 m2 (decreased) FSA • High ‘factor of safety’
   • Efficient use of fibre bundle capacity • 7.5 L/min blood flow
   • high ratio of gas exchange surface area to FSA  
  Disadvantage • Reduced (but acceptable) ‘factor of safety’ • 1.8 m2 FSA
    • Excessive ‘factor of safety’ for our patient population
Arterial line filter   Pall AL6 low prime Pall AL6 low prime
  1. * We begin training junior perfusionists with Midi card and after experience is gained, we move to SSR for routine cases. With further experience both by surgical and perfusionist teams, we move forward to Soft Shell Reservoir (SSR) for all cases regardless of complexity. The characteristics of these two options are described below.