A. Y. Gorvitovskaia1, L. A. Scrimgeour1, B. A. Potz1, C. D. Gordon1, N. Sellke1, A. Kuczmarski1, J. G. Fingleton1, A. Ehsan1, N. R. Sodha1, F. W. Sellke1 1Brown University School Of Medicine,Division Of Cardiothoracic Surgery,Providence, RI, USA
Introduction:
Cardiopulmonary bypass is associated with post-operative neurocognitive dysfunction; however, risk factors have not been clearly identified. Therefore, we hypothesize that lower hematocrit (Hct) levels may be correlated with post-operative neurocognitive dysfunction.
Methods:
Thirty patients underwent screening for neurocognitive dysfunction pre-operatively and at post-operative day four (POD4). All patients underwent cardiac surgery utilizing cardiopulmonary bypass including either coronary artery bypass grafting or valvular procedures. Patients with significant liver or renal dysfunction were excluded from the study. Patients were analyzed according to hematocrit and platelet levels at POD4, as well as by whether they received intra- and/or post-operative transfusions of packed red blood cells. Neurocognitive data is presented as a difference in RBANS standardized score based on sex and age from baseline to POD4 and comparisons analyzed by an unpaired Mann-Whitney U test.
Results:
There was a significant correlation between patients with hematocrit levels <24% and a decline in neurocognitive function at POD4 (p<0.05). While there was a decrease in platelet levels from pre-op to POD4, there was no significant association with lower platelet levels and neurocognitive decline (p=0.71). All patients experienced a decline in hematocrit levels throughout their hospital stay, but a decline in Hct was associated with a measurable neurocognitive decline by POD4. Those that had a lower Hct on POD4 had consistently lower Hct throughout their stay. Thirty percent of patients received transfusions of packed red blood cells at any time during their hospitalization; 20 percent received a transfusion post-operatively. There was no significant difference between those who received a transfusion at any time during their hospitalization and their neurocognitive function at POD4. However, there was a trend towards lower neurocognitive scores in those who attained a hematocrit greater than 24% by POD4 via a post-operative transfusion.
Conclusion:
Lower hematocrit levels are correlated with neurocognitive decline following cardiopulmonary bypass. While transfusion overall does not correlate with neurocognitive function, there was a trend towards lower neurocognitive function in those who received a post-operative transfusion. This suggests that their hematocrit was low enough at some point during their hospitalization to negatively affect their neurocognitive function. Therefore, despite goals to limit blood transfusions post-operatively, some patients may require transfusion at either a higher threshold or earlier time point to prevent neurocognitive decline.
