LAUSR

Introduction: Chronic myelomonocytic leukemia-0 (CMML) increases risk of leukemoid reaction, a systemic inflammatory response that increases morbidity and mortality. There is a paucity of reports in the literature describing this phenomenon in the post-cardiac surgery patient. Here we present a case of leukemoid reaction in the immediate post-operative setting of cardiac surgery in a patient with CMML. Description: A 66 year old male with CMML underwent coronary artery bypass grafting for multivessel coronary artery disease. Post-operatively, he arrived to the intensive care unit intubated and requiring low-dose epinephrine infusion (0.02 mcg/kg/min). The first 6 hours of his post-operative period were uneventful and he was extubated per routine. Within 2 hours post-extubation, he developed increased work of breathing, hypoxia, and severe hypotension requiring reintubation as well as fluid and vasoactive resuscitation. Bedside echocardiogram revealed normal biventricular function. His cardiac output remained normal while his systemic vascular resistance decreased, suggesting vasoplegic shock. Resuscitation attempts included addition of vasopressin, norepinephrine, hydroxocobalamin, methylene-blue, stress dose steroids, and intra-aortic balloon pump placement. He acutely developed severe metabolic acidosis with lactatemia (15mmol/L) refractory to sodium bicarbonate and continuous renal replacement therapy. He also developed disseminated intravascular coagulation, thrombocytopenia (38x10(9)/L), leukocytosis (51.5x10(9)/L), and transaminitis. Chest, abdomen, and pelvic imaging were negative for any acute process. After multidisciplinary discussion with critical care, cardiothoracic surgery, and hematology, tocilizumab 800mg q8h for three doses and 1g methylprednisolone were administered for possible leukemoid reaction associated with CMML crisis. Within 24 hours, hemodynamics improved, vasoactive support decreased, and pH normalized. Discussion: Post-cardiac surgery patients are predisposed to multifactorial post-operative shock. In patients with CMML, leukemoid reaction should be considered when differentiating refractory shock in the immediate post-operative period. Further research is indicated to create an algorithmic preoperative plan for this patient population.