Intra-operative intravenous fluid restriction reduces perioperative red blood cell transfusion in elective cardiac surgery, especially in transfusion-prone patients: a prospective, randomized controlled trial

Abstract

BackgroundCardiac surgery is a major consumer of blood products, and hemodilution increases transfusion requirements during cardiac surgery under CPB. As intraoperative parenteral fluids contribute to hemodilution, we evaluated the hypothesis that intraoperative fluid restriction reduces packed red-cell (PRC) use, especially in transfusion-prone adults undergoing elective cardiac surgery.Methods192 patients were randomly assigned to restrictive (group A, 100 pts), or liberal (group B, 92 pts) intraoperative intravenous fluid administration. All operations were conducted by the same team (same surgeon and perfusionist). After anesthesia induction, intravenous fluids were turned off in Group A (fluid restriction) patients, who only received fluids if directed by protocol. In contrast, intravenous fluid administration was unrestricted in group B. Transfusion decisions were made by the attending anesthesiologist, based on identical transfusion guidelines for both groups.Results137 of 192 patients received 289 PRC units in total. Age, sex, weight, height, BMI, BSA, LVEF, CPB duration and surgery duration did not differ between groups. Fluid balance was less positive in Group A. Fewer group A patients (62/100) required transfusion compared to group B (75/92, p < 0.04). Group A patients received fewer PRC units (113) compared to group B (176; p < 0.0001). Intraoperatively, the number of transfused units and transfused patients was lower in group A (31 u in 19 pts vs. 111 u in 62 pts; p < 0.001). Transfusions in ICU did not differ significantly between groups. Transfused patients had higher age, lower weight, height, BSA and preoperative hematocrit, but no difference in BMI or discharge hematocrit. Group B (p < 0.005) and female gender (p < 0.001) were associated with higher transfusion probability. Logistic regression identified group and preoperative hematocrit as significant predictors of transfusion.ConclusionsOur data suggest that fluid restriction reduces intraoperative PRC transfusions without significantly increasing postoperative transfusions in cardiac surgery; this effect is more pronounced in transfusion-prone patients.Trial registrationNCT00600704, at the United States National Institutes of Health.

Effect of priming solution and ultrafiltration on post-operative bleeding and blood transfusion in cardiac surgery. Randomized controlled trial

“…The use of crystalloid cardioplegic solution and more flexible perioperative fluid therapy protocols is a predictor of haemodilution and increased transfusion demand. 25,26 In their meta-analysis, Russell et al 12 found that demand for blood was not significantly reduced when using albumin prime, although the heterogeneity of the studies included and differences in transfusion criteria could have affected the results. The use of ultrafiltration, however, particularly modified ultrafiltration techniques, succeeds in significantly reducing blood transfusion requirements to nearly 1 unit, similar to the findings of our study.…”

Monitoring of brain oxygen saturation (INVOS) in a protocol to direct blood transfusions during cardiac surgery: a prospective randomized clinical trial

“…However, even though transfusions are clearly necessary in many cases, blood product use has been associated with increased morbidity [4] and long-term mortality [3] in cardiac surgery, and therefore attempts to reduce blood transfusions may contribute to reduced complications and improved outcomes. Consequently, several measures have been evaluated in an attempt to reduce blood transfusions during cardiac surgery [12], including tolerating lower hemoglobin values [5] and restricting parenteral fluids in order to avoid hemodilution [16]. Studies evaluating the effectiveness of restrictive fluid administration strategies in mitigating the precipitous intraoperative hematocrit drop, rather than restrictive blood transfusion strategies, are scarce.…”

“…We recently reported that, compared to liberal fluid administration, a restrictive parenteral fluid protocol significantly reduced intraoperative red blood cell (RBC) transfusions [17]. We also showed in a later RCT that restrictive fluid strategies may be more beneficial in patients prone to transfusion because of low preoperative hematocrit, female sex, or small BSA [16]. In both studies, re-infusion of washed blood from the thoracic cavities was used to reduce the need for transfusion.…”

“…All patients, regardless of group allocation, were treated using a restrictive parenteral fluid administration protocol, as described in our previous study [16]. Hemodynamic instability was managed using an algorithm aimed at limiting unnecessary fluid administration.…”

“…As “transfusion threshold” remains unclear for the CPB period, the attending anesthesiologist had the liberty to transfuse RBCs in patients where they were concerned that, based on medical history and/or co-morbid conditions, peri-operative anemia could lead to complications. C) Overall intraoperative fluid balance greater than +1.5 L (this value was chosen because it is greater than mean + 2SD in our previous report [16], therefore strongly indicating that the restrictive protocol was not applied). D) In group A patients, when an apparent drop of INVOS was not consistent in both hemispheres, the patient was excluded from the protocol, and the anesthesiologist had to call the trial coordinator.…”