Authors' response (to O'Connor and Fraser)

Th ese fi ndings demonstrate that early (admission) and late (post-admission) hyperlactatemia are both strongly associated with mortality in cardiac/vascular surgical patients (of whom a signifi cant number were postoperative cardiac patients). Th is would suggest that the inclusion of cardiac surgical patients did not weaken the association with mortality; it actually strengthened the overall association. These findings demand more study of lactate in the cardiac surgical cohort.