160 N . Kachoueian et al .: J Extra Corpor Technol 2024 , 56 , 159 – 166
Table 1 . del Nido ( DN ) cardioplegia solution ’ s components and the modified formula .
|
Modified DN |
Standard DN solution |
Carrier |
Ringer ’ s Lactated solution ( Sodium 130 mEq / liter ; Potassium 4 mEq / liter ; Calcium 3 mEq / liter ; Chloride 110 mEq / liter ; Lactate ( CH3CH ( OH ) COO� ) 28 mEq / liter ) |
Plasma-Lyte A ( sodium 140 mmol / L , potassium 5 mmol / L , magnesium 1.5 mmol / L , chloride 98 mmol / L , acetate 27 mmol / L , gluconate 23 mmol / L ), 1000 mL |
KCl |
26 mEq |
26 mEq |
NaHCO3 |
13 mEq |
13 mEq |
Mannitol |
3.26 g |
3.26 g |
Lidocaine |
130 mg |
130 mg |
Final volume |
1100 mL |
1100 mL |
Blood : carrier ratio |
1:4 |
1:4 |
pH |
6.2 ( 6.0 – 7.5 ) |
7.4 ( 6.5 – 8.0 ) |
Dosage and administration
Initial arrest by a dose of 20 mLkg �1 and subsequent 10 mLkg �1 re-dosing after 90 min
Initial arrest by a dose of 20 mLkg �1 and subsequent 10 mLkg �1 re-dosing after 90 min prohibited in Iran and most other countries [ 12 ]. Kantathut et al in their study in 2017 , for the first time , reported Ringer ’ s lactate as the base solution of del Nido cardioplegia and compared that with blood-based St . Thomas ’ cardioplegia . The findings of their study showed that del Nido cardioplegia was associated with more favorable myocardial protection with a lower incidence of arrhythmia and shorter duration of both intensive care unit ( ICU ) and hospital stay [ 12 ]. After an extensive literature review , we were unable to find studies comparing the clinical and laboratory impacts of del Nido and modified Ringer lactate-based del Nido among patients . Since the cost of Plasma-Lyte A solution is approximately nine times higher than the lactated Ringer ’ s solution in our setting , if this offers the same protection , this will significantly reduce the cost of care for patients . The present study compared these two types of del Nido cardioplegia solutions on myocardial damage markers , and other biochemical and clinical outcomes in patients undergoing cardiopulmonary bypass graft surgery ( CABG ) with CPB .
Patients and methods Study design
A prospective , randomized , blinded clinical trial was designed for patients undergoing CABG with CPB in Imam Hossein Hospital , Tehran-Iran in 2021 . The research ethics committee of Shahid Beheshti University of Medical Sciences approved the study protocol ( Ethics committee reference number : IR . SBMU . MSP . REC . 1401.023 ) and all of the study patients signed informed consent . Patients were enrolled if they were 18 – 75 years old , a candidate for elective CABG with CPB , receiving 3 – 4 vascular grafts , ejection fraction ( EF ) greater than 35 % and no multi-organ dysfunction . Vein grafts were harvested from the patient ’ s leg and the left internal mammary artery ( LIMA ) to left anterior descending ( LAD ) graft was done for all patients in the study groups . Patients with a history of cardiac surgery and infection in recent months and , a history of diabetes and kidney diseases were excluded .
Study patients were randomly , assigned to the modified del Nido cardioplegia with lactated Ringer ’ s solution ( trial ; LR DN ) and standard del Nido cardioplegia based on Plasma-Lyte A ( control ; PL DN ) groups , according to random block with random numbers table . Study protocol was registered on the Iranian Registry of Clinical Trials ( https :// irct . ir / trial / 65917 ; IRCT registration number : IRCT20210825052284N1 ) before starting patient recruitment . EF , duration of mechanical ventilation , inotrope administration , arrhythmia incidence , and ICU stay were the primary endpoints .
The study participants and researchers , all but perfusionists , were blinded to the intervention .
Conduct of cardiopulmonary bypass
CPB among participating patients in both groups , was managed by roller pomp ( target flow 2.4 L / min / m 2 of the body surface area ; range 2.2 – 2.6 ). Heparin was boluses at 300 units / kg , and the activated clotting time ( ACT ) level was maintained at higher than 480 s . ACT was measured using a Hemochron Signature Elite machine ( Werfen , MA , USA ). Mild hypothermia ( 32 ° C ) was used for all patients and mean arterial pressure was between 60 and 80 was used . Minimum blood pressure was defined as less than 60 mmHg and was managed by increasing CPB flow and / or administering phenylephrine . Blood pressure greater than 80 mmHg was managed by decreasing flow to 2.2 and / or infusion of nitroglycerine . Near Infra-red Spectrometry ( NIRS ) was used in all cases and lactate was also monitored by arterial blood gas every 45 min . SvO2 is not a standard of practice in our setting . The Red Blood Cell transfusion trigger was set at 21 – 24 % hematocrit , depending on criteria such as age , EF %, and Cerebrovascular baseline ( e . g ., carotid stenosis ). Blood gasses were managed using pH-stat titration technique according to the standards of care in our institution . We used the same techniques and parameter values for blood gas management in all patients in both groups .
A single dose of cardioplegia solution ( 20 mL / kg ; max 1000 mL ), modified or standard , was administered antegrade as previously described [ 9 ]. The components for standard DN and modified DN based in Ringer ’ s lactated solution is described in Table 1 . Cardioplegia solutions were prepared by the perfusionist under sterile conditions . Only the base solution was different between the two formulations . Sodium bicarbonate was added immediately before use by the perfusionist . The cardioplegia solutions were prepared immediately before administration and either Plasma-Lyte A ( Samen Pharmaceutical