Optimization of Prime Fluid Strategy to Preserve Microcirculatory Perfusion During Cardiac Surgery With Cardiopulmonary Bypass
Phase: NA
Conditions: Endothelial Dysfunction, Hemolysis, Fluid Overload
Sponsor: Amsterdam UMC, location VUmc

 
 
Optimization of prime fluid strategy to preserve 
microcirculatory perfusion during cardiac surgery with 
cardiopulmonary bypass – PRIME study  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Record number Clinical Trials.gov 
 
NCT05647200 
Date   
 
 
 
 
March 25th, 2025 

 
Explanation of Randomization Process 
In the present study, randomization was conducted on the day prior to surgery to ensure 
sufficient time for the preparation of CPB priming, in line with the logistical requirements of our 
hospital. While this approach was necessary to meet operational needs, it also introduced 
several challenges throughout the study.  
We encountered frequent changes in surgery dates due to logistical reasons, which led to the 
use of different types of cardioplegia. As the study was designed as a physiological proof-of-
principle study, we aimed to evaluate the effects of CPB prime fluid strategies on 
microcirculatory perfusion without the potential interference of additional hemodilution 
associated with crystalloid cardioplegia. Therefore, the study protocol was amended after start 
of the study to be able to replace already randomized patients if the type of procedure, or 
surgery date changed, leading to the use of a different cardioplegia and to increase the sample 
size until all groups had at least 8 patients available for the final analysis. The institutional 
review board approved this amendment. Due to the replacement of patients and the use of 
random block sizes of three, six, and nine an uneven distribution of patients across the three 
study groups occurred. As this was a physiological proof-of-principle study and the replaced 
and excluded patients were comparable to those included in the final analysis with regard to 
baseline characteristics we strongly believe that this amendment of the protocol did not 
influence the findings of this study. (Table 1 and eTable1)