Risk factors for prolonged ventilation after cardiac surgery using APACHE II, SAPS II, and TISS: comparison of three different models

Objective: To identify the risk for prolonged mechanical ventilation in car diac surgical patients. Design: Prospective study with retrospective combination of a second databa se. Patients: Six hundred and eighty-seven patients after cardiac surgery over a period of 12 months. Measurements: Demographic data were recorded preoperatively, and surgical p rocedures intraoperatively using a surgical database designed for quality c ontrol. Length of ICU and hospital stay, and hospital outcome were recorded . Severity of illness was assessed daily using APACHE II, SAPS II, and Orga n Failure Score. Intensity of treatment and nursing care was monitored by m eans of the Therapeutic Intervention Scoring System (TISS). Univariate and multivariate analyses were performed using logistic regression. The predict ive value of the identified variables was tested by the Wilcoxon test using the receiver operating characteristic curve. Main results: Sixty-two patients (9.0%) were ventilated for > 48 h and acco unted for 42.8 % of the total costs in the ICU. The pre- and intraoperative ly collected data produced a model with weak predictive capacity for prolon ged ventilation [area under curve (AUC) 73.22 and 71.08, respectively]. The use of TISS and SAPS postoperatively resulted in an effective model of pre diction (AUC 93.76). Adding the occurrence of reoperation, reintubation, em ergency transfusion, intraaortic balloon pumping, and need for total parent eral nutrition to the model further improved its predictive capacity (AUC 9 4.74). Conclusions: The present results strongly suggest that data collected posto peratively using established scoring systems as well as documented events o f high clinical impact for risk assessment and quality control are reliable predictors of prolonged ventilation.