Cold Antibody and Persistent Intravascular Hemolysis after Surgery under Hypothermia

Intravascular hemolysis began during cardiac surgery under hypothermia in a patient with an anti‐HI cold agglutinin. The hemolysis continued for a week with destruction of an amount of red blood cells equal to the mass of A2B cells transfused. At the same time, 51Cr‐tagged A1 cells were surviving normally. The destruction in vivo of HI positive red blood cells was later duplicated in vitro by pre‐incubating group O red blood cells with the patient's plasma in the cold at a time when he was hematologically normal. This cause of clinical hemolysis must be a rare complication of hypothermia.