10 C . W . Striker and J . A . Reagor : J Extra Corpor Technol 2025 , 57 , 9 – 13
Table 1 . del Nido cardioplegia solution .
Constituents
Plasma-Lyte A Potassium ( KCL ) Magnesium ( MgSO 4 ) Sodium Bicarbonate ( NaHCO 3 ) Mannitol Lidocaine Total volume
Table 2 . Mee cardioplegia solution .
Constituents patients < 10 Kg
Sterile water Albumin 25 % Potassium ( KCL ) Sodium bicarbonate ( NaHCO 3 ) Mannitol 20 % Calcium chloride ( CaCl 2 ) Dextrose 50 % NaCl Total volume
Constituents patients > 10 Kg
Sterile Water NaCl 0.9 % Potassium ( K + ) Sodium Bicarbonate ( NaHCO 3 ) Mannitol 20 % Calcium Chloride ( CaCl 2 ) Dextrose 50 % NaCl Total Volume
and appropriate informed consent was obtained . Exclusions for participation included patients who did not receive dNC or those who did not receive magnesium sulfate administration of 25 mg / kg up to 1 g post-cross-clamp removal .
Conduct of CPB
Quantity
1 L 26 mEq 2 gm 12 mEq 3.26 gm 130 mg 1059 mL
Quantity
353 mL 100 mL 15 mEq 26 mEq 2.5 gm 52 mg 5.63 mL 23.28 mEq 511 mL
Quantity
706 mL 200 mL 30 mEq 10 mEq 10 gm 104 mg 11.26 mL 46.56 mEq 1005 mL Cardiopulmonary bypass was conducted in a similar fashion by eight pediatric and congenital perfusionists , in adherence with department guidelines , for four congenital cardiothoracic surgeons . Age and weight-appropriate circuitry and a 3.0 cardiac index flow target based on body surface area were utilized . Bypass circuits were comprised of oxygenators from the Terumo FX series ( Terumo Cardiovascular , Ann Arbor , MI , USA ), tubing coated with Terumo ’ s X-Coating ( Terumo Cardiovascular , Ann Arbor , MI , USA ), and either the DHF02 or DHF06 hemoconcentrator ( LivaNova , London , UK ). Roller pumps were used with appropriately sized pump boots for all cases and roller pump occlusion was set for each case by the pressure drop method (~ 2 mmHg drop in pressure per second ). CPB circuits were primed with packed red blood cells ( PRBC ) as necessary to ensure a post-dilutional hematocrit greater than 25 % on bypass . PRBC units were processed in a Fresenius Kabi Continuous Autotransfusion System ( CATS ) cell savage device ( Terumo Cardiovascular , Ann Arbor , MI , USA ) and washed with Plasmalyte-A ( Baxter Healthcare , Deerfield , IL ,
USA ) before administration into the CPB pump . Patients weighing less than eight kilograms received at least one full unit of fresh frozen plasma ( FFP ) preserved in Anticoagulant Citrate Dextrose ( ACD-A ) solution ( Baxter Healthcare , Deerfield , IL , USA ), 120 mLs of which was administered via the CPB prime upon initiation of bypass and the rest of the unit given during CPB . In the event , that patients received two or more units of PRBCs during CPB , one unit of FFP for every two units of PRBC was administered during CPB . No platelets or cryoprecipitate were administered during CPB . Transfusion of PRBC during CPB and / or the use of modified ultrafiltration post- CPB was indicated to maintain an on-bypass hematocrit above 25 % and to ensure a hematocrit greater than 30 % for post-repair acyanotic patients and greater than 40 % for cyanotic patients . Bypass for patients with cyanotic lesions , patients with a pO 2 less than 80 mmHg , was initiated at a cyanotic pO 2 of approximately 50 mmHg . The pO 2 upon initiation of CPB for acyanotic patients was approximately 200 mmHg . Bypass was initiated upon reaching a target heparin concentration as determined by individual heparin dose response ( HDR ), targeting an activating clotting time ( ACT ) of 480 s and minimum ACT of 400 s measured via the Medtronic Heparin Management System ( HMS ), ( Medtronic , Minneapolis , MN , USA ). An ACT of greater than 480 s and a heparin concentration greater than or equal to the HDR target were maintained during CPB and measured every 30 min . Depending upon the extent of the repair necessary , patients were cooled as low as 28 ° C , measured via bladder temperature , and rewarmed to 36 ° C prior to termination from bypass . Conventional ultrafiltration was utilized during CPB with a target fluid balance of 0 to �40 mL / kg during the period of CPB and MUF [ 2 ]. Dilutional ultrafiltration ( DUF ) was performed with Plasma-Lyte A ( Baxter Healthcare , Deerfield , IL , USA ) with 20 mEq sodium bicarbonate and 200 mg calcium chloride per liter . DUF clearance volumes targeted 50 – 200 mL / kg during CPB . Upon stable termination of CPB , heparin was reversed based upon the heparin-protamine concentration titration measured within 30 min of CPB termination via the HMS . A post-protamine heparin concentration of zero and an ACT at or near baseline were considered to be acceptable heparin reversal criteria .
Cardioplegia circuit setup and dosing regimen
Cardioplegia was administered via a nonrecirculating , custom circuit comprised of SMART-coated tubing and a CSC-14 heat exchanger ( LivaNova , London , UK ) containing approximately 100 mL of volume . dNC ( Central Admixture Pharmacy Solutions , Cleveland , OH , USA ) was administered upon cross-clamp application at a 20 mL / kg induction dose in a 1:4 ratio of blood to crystalloid . Maintenance doses of 10 – 20 mL / kg were administered as necessary at a frequency of every 90 – 120 min of cross-clamp time . Cardioplegia was administered at temperatures between 4 and 6 ° C .
Study procedure
Consented patients undergoing CPB with dNC arrest had two blood samples collected from the heart-lung machine sampling manifold and measured for magnesium levels .