Does the Type of Cardioplegic Technique Influence Hemodilution and Transfusion Requirements in Adult Patients Undergoing Cardiac Surgery?

During cardiac surgery, myocardial protection is performed using diverse cardioplegic (CP) solutions with and without the presence of blood. New CP formulations extend ischemic intervals but use high-volume, crystalloid-based solutions. The present study evaluated four commonly used CP solutions and their effect on hemodilution during cardiopulmonary bypass (CPB). Records from 16,670 adult patients undergoing cardiac surgery with CPB between February 2016 and January 2017 were reviewed. Patients were classified into one of four groups according to CP type: 4-1 blood to crystalloid (4:1), microplegia (MP), del Nido (DN) and histidine-tryptophan-ketoglutarate (HTK). Covariate-adjusted estimates of group differences were calculated using multivariable logistic and linear mixed effects regression models. The primary end point was intraoperative transfusion of allogeneic red blood cells (RBCs), with a secondary end point of intraoperative hematocrit change. Among all patients, 8,350 (50.1%) received 4:1, 4,606 (27.6%) MP, 3,344 (20.1%) DN, and 370 (2.2%) HTK. Both 4:1 and MP were more likely to be used in patients undergoing coronary revascularization surgery, whereas DN and HTK were seen more often in patients undergoing valve surgery (p < .001). The highest volume of crystalloid CP solution was seen in the HTK group, 2,000 [1,754, 2200], whereas MP had the lowest, 50 [32, 67], p < .001. Ultrafiltration usage was as follows: HTK-84.9%. DN-83.7%, MP-40.1%, and 4:1-34.0%, p < .001. There were no statistically significant differences on the primary outcome risk of intraoperative RBC transfusion. However, statistically significant differences among all but one of the pair-wise comparisons of CP methods on hematocrit change (p < .05 or smaller), with MP having the lowest predicted drift (-7.8%) and HTK having the highest (-9.4%). During cardiac surgery, the administration of different CP formulations results in varying intraoperative hematocrit changes related to the volume of crystalloid solution administered.

The effects of venous cannulation technique and cardioplegia type on plasma potassium concentration and arterial blood pressure during cardiopulmonary bypass.

The cannulation method and cardioplegia solution used during cardiopulmonary bypass (CPB) may both influence plasma potassium concentrations ([K+]) and mean arterial blood pressure (MAP). Bi-caval or right atrial cannulation methods are routinely used in conjunction with crystalloid or blood cardioplegia. We investigated the influence of cannulation method and cardioplegia solutions on plasma [K+] and MAP during cardiopulmonary bypass. Sixty consecutive patients undergoing elective coronary artery bypass grafting (CABG) using CPB were studied. They were randomly divided into three groups of 20 patients. Patients in Group A underwent bi-caval venous cannulation and received crystalloid cardioplegia. Group B patients underwent right atrial cannulation and received crystalloid cardioplegia. Group C patients underwent right atrial cannulation and received blood cardioplegia. In each case. cardioplegia was administered antegrade via the aortic root. Plasma [K+], MAP. and hemoglobin concentration (Hb) were measured over an 8-min period following cardioplegia administration (pilot studies indicated pressure changes occuring post cardioplegia administration up to this time). The combination of bi-caval cannulation and crystalloid cardioplegia (Group A) was associated with the least increase in plasma [K+] and no decrease in MAP. The maximum [K+] for this Group was 4.2 mmol/L (4.6% increase). The minimum mean pressure was 57 mmHg (13.6% increase). Both right atrial cannulation groups (B and C) showed a large rise in plasma [K+] and a decrease in MAP. Group B maximum [K+] was 5.2 mmol/L (27.5% increase). Group C was also 5.2 mmol/L (26.0% increase). Group C showed the largest pressure decrease, the minimum mean pressure was 45 mmHg (21.3% decrease). The Group B minimum mean pressure was 45 mmHg (8.7% decrease). Our results show that patients undergoing CPB operations who are deemed to be at increased risk of suffering adverse effects from hypotensive episodes may benefit from bicaval cannulation and caval snaring, in preference to right atrial cannulation. Crystalloid cardioplegia may be preferable to blood cardioplegia in these cases to maintain the MAP.

Comparison of two cardioplegia solutions using thermodilution cardiac output in neonates and infants.

BACKGROUND: Information from clinical studies is limited regarding the optimal method for myocardial protection in immature hearts, and specifically the benefits of different cardioplegia (CP) formulations. We compared two CP techniques by evaluation of the cardiac index using thermodilution catheters. METHODS: The study cohort includes 102 neonates and infants (aged 2 to 269 days) undergoing biventricular repair surgery. A total of 52 patients were managed with commercially available crystalloid CP ("standard CP") and 50 had a custom mix of crystalloid CP with dilute blood ("custom CP"). Repeated-measures analysis of variance was applied to compare the cardiac index every 3 hours during the 24-hour postoperative period between the two groups and stratified by diagnosis. Adjustment for possible confounders was used to more objectively compare the groups. RESULTS: Standard crystalloid CP provided superior myocardial protection in patients who had transposition of great arteries (p < 0.001), and this advantage held after adjusting for age and cross-clamp time. Shorter ventilatory times and intensive care unit stays were also noted for the standard CP group (p = 0.01). Cardiac index after cardiopulmonary bypass was lower in patients who had transposition of great arteries and intact ventricular septum compared with the group who had transposition of great arteries and ventricular septal defect; and in both subgroups, the standard CP technique was superior to the custom CP solution. Age at operation was inversely correlated with the cardiac index. CONCLUSIONS: Younger patients, particularly neonates, have a significantly higher postoperative cardiac index with standard CP than with custom CP. The advantage is not apparent beyond the neonatal period.