D. J. Picone1, N. R. Sodha1, T. C. Geraci1, J. T. Machan1, F. W. Sellke1, W. G. Cioffi1, S. F. Monaghan1 1Brown University School Of Medicine,Surgery,Providence, RI, USA
Introduction: Systemic inflammatory response syndrome (SIRS) frequently occurs following cardiac surgery, a controlled traumatic event. Typically, emphasis is placed on the white blood cell count; however, immune cell responses following trauma have been associated with poor outcomes. We hypothesize that lymphocyte loss and lack of recovery after cardiac surgery will predict poor outcomes.
Methods: This is a retrospective review of all adult post-cardiac surgery patients from a single institution from Oct 2008 to Oct 2015. Patients were included if they had more than two complete blood counts (CBC) drawn in the first 7 days post operatively. Demographic data, complications, hospital and ICU length of stays, operative data, and mortality were obtained from the Society of Thoracic Surgery (STS) database. Laboratory data was obtained from the medical record. Leukocyte, neutrophil, and lymphocyte counts were retained. Patients were grouped based on the pattern of response of elevation/depression and normalization versus failure of normalization for each component (leukocyte, neutrophil, lymphocyte). Kaplan-Meier curves and odds ratios were used to analyze association with 30 day mortality, development of pneumonia, renal failure, post-operative sepsis, and all complications.
Results: 2401 patients were included in the leukocyte group and 1795 patients in both the neutrophil and lymphocyte groups. Patients who developed increased leukocytosis that remained elevated within 7 days had an increased risk of mortality (8.7%), compared to both those who normalize (2.9%, p <0.0001) and those who did not develop a leukocytosis (1.8%, p <0.0001). There was no difference in mortality for the neutrophil or lymphocyte groups. Patients who did not develop post-operative lymphopenia had decreased risk compared both to those with persistent lymphopenia and those with normalization of lymphopenia, as indicated respectively in the following: pneumonia (OR 0.42 (CI 0.25-0.69), 0.49 (CI 0.24-0.98)); renal failure (OR 0.21 (CI 0.12-0.39), 0.36 (CI 0.15-0.8)); sepsis (OR 0.21 (CI 0.06-0.64), 0.11 (CI 0.03-0.36)); all complications (OR 0.42 (CI 0.30-0.61), 0.37 (CI 0.23-0.58)). Leukocytosis that failed to normalize was associated with increased risk of pneumonia (OR 2.5 (CI 1.2-3.4)) and all complications (OR 3.46 (CI 2.5-4.8)). There was no associated complication risk with neutrophilia.
Conclusion: Failure to normalize leukocytosis after cardiac surgery is associated with higher risk of mortality. Development of lymphopenia in the post-operative period is associated with increased risk of post operative complications. Use of these routinely ordered labs may help identify patients at risk for complications and who should not be “fast tracked” for discharge. Future work will compare the predictive nature of these laboratory tests versus standard predictors from the STS database.