APACHE-ll-score-based identification of an escalating systemic inflammatory response syndrome (SIRS) early after cardiac surgery with the assistance of the cardiopulmonary bypass (CPB)

Multiorgan dysfunction syndrome (MODS), sepsis and septic shock are the leading causes of death in the postoperative phase after cardiac surgery assisted by the cardiopulmonary bypass (CPB). The APACHE-II score has been validated for identifying patients at risk of developing MODS in the intensive care unit and was used in this study to detect post-pump inflammatory response. Using the APACHE-II score on the first postoperative day, in a monocenter patient population of the years 1988–1990, a risk stratification for sepsis after cardiac surgery had been achieved (Pilz et al: Chest 1994, 105:76–82). Three groups had been discerned: an APACHE-II score ≥ 19–23 described a patient group at risk of developing sepsis with a mortality of 14%; an APACHE-II score ≥ 24 implied a very high mortality of 76%; patients with a score < 19 had a low risk of developing sepsis.

This risk stratification was renewed in 1996 in another center in a university setting. So far in 223 patients, who had undergone elective open-heart surgery from June to October, APACHE-II score was determined on the morning of the 1st postoperative day and correlated with mortality: 28-day-mortality amounted to 3.8% in patients with a score < 19; 12.5% in patients with a score of ≥ 19–23; and 31.2% in patients with a score ≥ 24 (21 patients still in validation process). These APACHE-II score (≥ 24)-identified high-risk patients significantly differed from patients with a score < 19 in the duration of the extracorporeal circulation (score < 19: 98.1 ± 35.4 min; score ≥ 19–23: 120.1 ± 64.1 min; score ≥ 24: 134.8 ± 41.1 min), the duration of mechanical ventilation in the ICU (score < 19: 26.1 ± 58.6 h; score ≥ 19–23: 78.6 ± 74.7 h; score ≥ 24: 145.7 ± 139.7 h) and age (score < 19: 62.4 ± 9.1a; score ≥ 19–23: 62.5 ± 12.4a; score ≥ 24: 69.8 ± 4.6a) of the patients. The groups were not significantly different with respect to the average pre-operative NYHA degree of heart failure.

Conclusion

The APACHE-II score on the morning of the 1st postoperative day after elective cardiac surgery with CPB allows for a risk stratification. In the patient population investigated, the APACHE-II score (≥ 24)-defined high-risk group had a better prognosis than the patients with the same score values examined in 1988–1990.