Attributable harm of severe bleeding after cardiac surgery in hemodynamically stable patients

Background We sought to quantify the effect of severe postoperative bleeding in hemodynamically stable patients following cardiac surgery. Methods We reviewed the charts of all cardiac surgery patients operated on at our institution between 2010 and 2014. After excluding patients with tamponade or MAP <60, we propensity matched patients having chest tube output >300 mL in the first postoperative hour, >200 mL in the second, and >100 mL in the third (“bleeding” group) with patients having <50 mL/h of chest tube output (“dry” group). The primary outcome was a composite of morbidity or mortality (excluding reexploration). Results 5016 patients were operated on between 2010 and 2014; of these, we included the records of 84 bleeding and 498 dry patients. Propensity matching resulted in 68 pairs of patients well-matched on baseline and operative variables. As compared to matched dry patients, bleeding patients were more likely to experience the primary outcome of any morbidity/mortality (36.8 vs. 13.2 %, p = 0.002), as well as ventilation >24 h (33.8 vs. 7.4 %, p < 0.001) and 30-day mortality (11.8 vs. 1.5 %, p = 0.02). Of the 84 bleeding patients, 46 underwent reexploration for bleeding within 24 h of surgery. A subgroup analysis propensity matching bleeding patients who were or were not reexplored <24 h demonstrated similarly poor outcomes in each group (primary outcome, 44.7 % reexplored vs. 50.0 % non-reexplored, p = 0.65), though reexplored patients were far less likely to require hematoma evacuation/washout >24 h after surgery (0 vs. 18.4 %, p = 0.005). Conclusions Even among hemodynamically stable patients, severe bleeding is associated with markedly worse outcomes following cardiac surgery.