The Journal of ExtraCorporeal Technology No 56-3 | Page 11

86 B . Ali et al .: J Extra Corpor Technol 2024 , 56 , 84 – 93

Table 1 . Composition of routine and modified del Nido cardioplegia .

chloride ( 2 mEq / mL ) 13 mL , and Lidocaine 1 % 13 mL . The bicarbonate level of rdNCS is 20 mL , which is slightly higher than the typical level of 13 mL in original del Nido cardioplegia . This increase is necessary to maintain the solution ’ s acidic pH at a somewhat basic level . Elevated bicarbonate levels can elevate the risk of post-clamp-off arrhythmia and the need for defibrillation . However , the Lidocaine component of del Nido cardioplegia mitigates these risks by helping to control such arrhythmias .

On the other hand , the rldNCS composition comprises lactated Ringers 800 mL , containing Sodium ( Na +) 130 mEq / L , Chloride ( Cl� ) 109 mEq / L , Potassium ( K +) 4 mEq / L , Calcium ( Ca ++) 1.5 mEq / L , Magnesium ( Mg ++) Lactate 28 mEq / L , and Tonicity 276 mOsm / L ( Hypotonic ), with a pH of approximately 6.5 . This solution also includes additives such as Mannitol 20 % 16.3 mL , Magnesium sulfate 50 % 4 mL , Sodium bicarbonate 8.4 % ( 1 mEq / mL ) 13 mL , Potassium chloride ( 2 mEq / mL ) 13 mL , and Lidocaine 1 % 13 mL .

Finally , the prdNCS composition comprises plain Ringers 800 mL , containing Sodium ( Na +) with 147 mEq / L Chloride ( Cl� ) 155 mEq / L , Potassium ( K +) 4 mEq / L , Calcium ( Ca ++) 4 mEq / L , and Tonicity 311.3 mOsmol / L , with a pH of approximately 7.4 . This solution also includes additives such as Mannitol 20 % 16.3 mL , Magnesium sulfate 50 % 4 mL , Sodium bicarbonate 8.4 % ( 1 mEq / mL ) 13 mL , Potassium chloride ( 2 mEq / mL ) 13 mL , and Lidocaine 1 % 13 mL .

The composition of each solution can also be observed in Table 1 . The cardioplegia solutions were administered through a single dose of 20 mL / kg maximum of 1000 mL for patients weighing more than 50 kg . A single dose of del Nido cardioplegia provides adequate myocardial protection for 90 min and reduces the myocardial temperature to less than 15 ° C , minimizing oxygen consumption . However , 3 / 4 ( 75 %) of the dose is necessary for effective myocardial protection [ 18 ]. The usual delivery temperature of cardioplegia solution was 4 ° C , system pressure of 100 – 200 mm Hg , and pump flow was 200 – 300 mL / min [ 19 ]. No additional doses were infused among participants .

Laboratory assessment

During the study , arterial blood was collected from patients at four different times – after anesthesia induction ( baseline ), 2 h , 12 h , and 24 h post-surgery . The collected blood samples were then used to conduct serum CK-MB , Troponin T , Troponin I , and lactate tests . The CK-MB enzyme is predominantly present in cardiac muscle cells and is vital for their energy production process . In the event of heart muscle damage , such as during a heart attack , CK-MB is released into the bloodstream . The typical CK-MB range is between 5 and 25 U / L . Troponin T is an essential protein present in heart muscle cells that is responsible for regulating the contraction mechanism of the cardiac muscle . It is a crucial component of the troponin complex that oversees the heart ’ s muscle contractions . In the event of heart muscle damage , such as during a myocardial infarction ( heart attack ), Troponin T is released into the bloodstream . The typical range for Troponin T is below 0.01 ng / mL . Troponin I is a vital protein present in the heart muscle that plays a crucial role in regulating cardiac muscle contraction . It is exclusively found in the heart and is released into the bloodstream when heart muscle cells sustain damage . The normal value of Troponin I stands at < 0.04 ng / mL . Lactate , which is also referred to as lactic acid , is a natural byproduct of the body ’ s anaerobic metabolism . This process occurs when glucose is broken down in the absence of sufficient oxygen levels . Lactate is an alternative pathway for energy production that the cells must resort to under such conditions . The normal range for lactate is 4.5 – 19.8 mg / dL . The hospital ’ s clinical diagnostic laboratory performed the measurements , ensuring that their devices were regularly checked and calibrated as part of their daily practice . The laboratory staff was kept unaware of the patients ’ assigned groups . The study assessed myocardial protection by examining the increase in cardiac biomarkers in the presence of Electrocardiogram ( ECG ) abnormalities or symptoms . Along with the laboratory assessment team of researchers closely monitored the surgical and clinical outcomes during the perioperative period and hospital stay . Clinical outcomes

The primary outcomes were assessed for myocardial protection between routine and modified del Nido cardioplegia solution using the serum levels of cardiac enzymes including CK isoenzyme MB ( CK-MB ), Troponin T , Troponin I , and lactate in the immediate postoperative period 2 h as well as 12 h and 24 h , postoperatively . It ’ s important to note that cardiac markers , including CK-MB , Troponin T , Troponin I , and lactate , were not monitored during the surgery because the heart is typically bypassed during this period . Consequently , the patient ’ s blood is diverted to a reservoir , leading to dilution and potentially altering the true values of these cardiac markers . The secondary outcomes include intraoperative assessments of additional myocardial protection measures ; Incidence of postaortic clamp-off ventricular fibrillation requiring electrical