Acute Normovolaemic Haemodilution With Crystalloids in Coronary Artery Bypass Graft Surgery: A Preliminary Survey of Haemostatic Markers

Introduction: Acute normovolaemic haemodilution (ANH) is a safe and cost-effective blood conservation strategy in procedures with great blood loss. It eliminates the risk of administrative errors and also contaminations that may occur whenever banked blood is used. Classically, haemodilution is regarded as causing coagulopathy. This study was designed to determine the effect of crystalloids on measured coagulation values and perioperative blood loss following ANH in patients undergoing elective coronary revascularization.

Methods: Following a prospective case-control study one hundred candidates for CABG (50 cases in the ANH group and 50 in the control group) were included. Blood samples for coagulation testing haematocrit and platelet levels were collected before ANH, after cardiopulmonary bypass (CPB), and upon arrival at the intensive care unit (ICU). Differences were considered statistically significant with P values < 0.05.

Results: There was no statistically significant difference between chest tube drainage in the two groups. The number of patients using PRBC (packed red blood cell) or FFP (fresh frozen plasma) was significantly higher in the control group in comparison to the ANH group (P < 0.05). The PT increased significantly after arrival in the ICU in both groups (P < 0.001) but there was no between-group difference (P = 0.22). aPTT not only did not change significantly in the ICU relative to the baseline pre ANH values in both groups (P > 0.05) but also did not show any between-group difference (P = 0.69). There was no statistically significant difference in the aCT of the control and the ANH group after arrival to the ICU (P = 0.09). Hct and Plt decreased significantly in both groups after CPB and arrival at ICU.

Conclusion: ANH reduced the need for PRBC and FFP by 58% and 74%, respectively. Regarding the increase in PT and decrease in Plt count, we concluded that performing ANH with saline solution (SS) in patients undergoing CABG surgery may cause a non-clinically significant change in coagulation state.