Impact of Noncolloid or Colloid Priming of the Heart–Lung Machine on in-Hospital Outcome after Coronary Artery Bypass Surgery

Objectives: Noncolloid priming is cost effective, free from immunological reactions and independent from human plasma delivery. However there is some debate on negative impact of intraoperative low plasma colloid pressure. Aim of the study was to rule out adverse effects of noncolloid priming on postoperative outcome.

Methods: We investigated 520 consecutive patients including emergency cases who had isolated on-pump coronary bypass grafting in 2009 by retrospective analysis in a single-center study. During this year non-colloid priming was introduced as alternative. Type of priming was chosen due to the preference of the surgeon. A comprehensive dataset of pre-, intra- and postoperative parameters was generated by review of patient charts and IT based datasets, giving 118 items in total. 294 cases had colloid (group I) and 226 noncolloid (group II) priming. Results are given as median and quartiles for continuous or percentages for categorical variables. Pearson chi-square test and Mann-Whitney U-test were applied as appropriate (p < 0,05).

Results: There were no differences with respect to age, sex, left ventricular function, rate of emergency procedures and comorbidities between both groups. Mean age was 68.8 (60.9–74.9) years in group I and 70.6 (63.7–75.0) years in group II. Time of extracorporeal circulation was 109.0 (92.0–123.8) minutes in group I and 111.0 (90.5–128.0) minutes in group II. Despite equal perfusion times we found a higher need for volume replacement during extracorporeal circulation using non-colloid priming. Volume status at the end of the operation was +737 (+700 ± 2,463) mL in group I and +1,600 (+700 ± 2,463) in group II (p < 0.0001). However, this did not translate into different in-hospital outcomes. Fluid balance has equalized in both groups on day 2. Time on respirator was 15.8 (11.3–21.6) hours in group I and 16.2 (12.0–21.9) in group II. There was no difference with regard to need for vasopressor treatment or serum lactate levels (2.8; 1.6–5.1 mg/dL in group I and 3.6; 1.6–6.0 mg/dL in group II) as surrogate parameters indicating systemic inflammatory reactions. In hospital mortality in this all comers cohort was 3.1% with no difference between both groups.

Conclusion: The use of noncolloid priming is safe in standard cardiac surgery in adults. However there might be an increased need of crystalloid fluids during extracorporeal circulation. This has to be considered in more complex operations with longer perfusion times.