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PLoS One. 2017 Oct 30;12(10):e0187122. doi: 10.1371/journal.pone.0187122. eCollection 2017.

Derivation and validation of a preoperative risk model for postoperative mortality (SAMPE model): An approach to care stratification.

Author information

1
Department of Surgery, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
2
Anesthesia and Perioperative Medicine Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.
3
Medical Science Postgraduation Program,- Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
4
Laboratory of Pain and Neuromodulation, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
5
Department of Statistic-Instituto de Matemática e Estatística-UFRGS, Porto Alegre, RS, Brazil.

Abstract

Ascertaining which patients are at highest risk of poor postoperative outcomes could improve care and enhance safety. This study aimed to construct and validate a propensity index for 30-day postoperative mortality. A retrospective cohort study was conducted at Hospital de Clínicas de Porto Alegre, Brazil, over a period of 3 years. A dataset of 13524 patients was used to develop the model and another dataset of 7254 was used to validate it. The primary outcome was 30-day in-hospital mortality. Overall mortality in the development dataset was 2.31% [n = 311; 95% confidence interval: 2.06-2.56%]. Four variables were significantly associated with outcome: age, ASA class, nature of surgery (urgent/emergency vs elective), and surgical severity (major/intermediate/minor). The index with this set of variables to predict mortality in the validation sample (n = 7253) gave an AUROC = 0.9137, 85.2% sensitivity, and 81.7% specificity. This sensitivity cut-off yielded four classes of death probability: class I, <2%; class II, 2-5%; class III, 5-10%; class IV, >10%. Model application showed that, amongst patients in risk class IV, the odds of death were approximately fivefold higher (odds ratio 5.43, 95% confidence interval: 2.82-10.46) in those admitted to intensive care after a period on the regular ward than in those sent to the intensive care unit directly after surgery. The SAMPE (Anaesthesia and Perioperative Medicine Service) model accurately predicted 30-day postoperative mortality. This model allows identification of high-risk patients and could be used as a practical tool for care stratification and rational postoperative allocation of critical care resources.

PMID:
29084236
PMCID:
PMC5662221
DOI:
10.1371/journal.pone.0187122
[Indexed for MEDLINE]
Free PMC Article

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