Purpose of the study: To compare predicted death rate (PDR) numbers, computed in commonly used severity-of-illness and prognostic scoring systems (Portsmouth-POSSUM, SAPS 2, MPM 2, MPM for cancer patients, LODS, ODIN i TRIOS) on the first and on the third postoperative days with the mean PDR calculated from the scales. Assessment of the mean PDR values. Analysis of the main risk factors that affect postoperative mortality.
Material and methods: There were analyzed 187 cases of non-survivors and 100 cases of survivors treated in surgical wards at University Hospital in Kraków. In each case there were compared groups of patients with defined pathological syndromes (sepsis, thromboembolism, left-heart failure, respiratory tract infections, trauma, oncology, multiorgan failure and haemorrhage) with PDR calculated in seven severity-of illness and prognostic scoring systems on the first and on the third postoperative day and mean PDR computed from seven PDR numbers. There was used calculation of OR (odds ratio) with 95% CI (confidence interval) and the Pearson product moment correlation coefficient.
Results: The main risk factors of early deaths (that occurred within the first 3 postoperative days) in the group of nonsurvivors (n = 187) were: emergencies (p < 0.001), perioperative haemorrhage (p < 0.002), and trauma (p = 0.02). The late deaths (that occurred > 3 postoperative days) were caused by repeated surgery (p < 0.001), oncology (p = 0.019), then comorbidities (p = 0.025) and sepsis (p = 0.072). The Pearson product moment correlation coefficients for mean PDR computed on the 1st and 3rd postoperative day were respectively -0.4517 and -0.4012. None of the scales showed good discriminant characteristics in patients with cardiovascular diseases and pneumonia. In all scoring systems, except of the MPM for cancer patients and TRIOS, the PDR values correlated significantly with the preoperative ASA group assessment.
Conclusions: There is no commonly used severity-of-illness scoring system that could properly evaluate intensive care unit patients. Discriminative abilities of the scoring systems do not present any unique features that might affect selection of one of them. The mean PDR value computed from available scales is a reasonable descriptive and prognostic alternative.