[Suppurative mediastinitis after open heart surgery: in comparison between infants-children and adults].

Among 361 consecutive patients who underwent open surgery from Jan. 1987 to Sept. 1991, risk factors and clinical courses were analyzed retrospectively in comparison between infants-children and adults. Seven mediastinitis (4.0%) occurred in 173 adult patients (20 to 75 y/o, mean: 54.4 y/o) and were not associated with age, sex, type of disease, and duration of operation or cardiopulmonary bypass. Postoperative mediastinitis significantly increased in the patients with low output syndrome (LOS) determined as use of IABP and/or assistant circulations (p < 0.001) and reexploration for bleeding or tamponase was associated with an increased risk for mediastinitis (p < 0.01). Five mediastinitis (2.7%) occurred in 188 infants and children (0 to 17 y/o, mean: 4.2 y/o). All patients involved with mediastinitis were less than 12 month old (2.6 +/- 3.3 month). None of the other factors was associated with an increased risk for this complication. Bacterial cultures of exudate were positive in 11 of 12 patients, and identified as MRSA in 10 and Staphylococcus epidermidis in one. In the seven of adult patients, two developed sepsis and four died with other organic failures or mediastinal bleeding. All five of infants healed after postoperative 33 to 145 days. The immature state of immune response might associate with postoperative mediastinitis in infants, whether LOS may be important in the immune suppression by surgical stress in adults, and the prognosis of mediastinitis might be effected by prolonged depression of postoperative cardiac function in adult patients.