Nonoperative Management in Blunt Splenic Trauma: Can Shock Index Predict Failure?

Abstract

Predicting failure of nonoperative management (NOM) in splenic trauma remains elusive. Shock index (SI) is an indicator of physiologic burden in an injury but is not used as a prediction tool. The purpose of this study was to determine if elevated SI would be predictive of failure of NOM in patients with a blunt splenic injury. Adult patients admitted to a level-1 trauma center from January 2011 to April 2017 for NOM of splenic injury were reviewed. Patients were excluded if they underwent a procedure (angiography or surgery) prior to admission. The primary outcome was requiring intervention after an initial trial of noninterventional management (NIM). An SI>0.9 at admission was considered a high risk. Univariate and multivariate analyses were used to identify predicators of the failure of NOM. Findings were subsequently verified on a validation cohort of patients. Five hundred and eighty-five patients met inclusion criteria; 7.4% failed NIM. On an univariate analysis, findings of pseudoaneurysm or extra-arterial contrast on computed tomography did not differentiate successful NIM versus failure (8.1% versus 14.0%, P=0.18). Age, the American Association for the Surgery of Trauma injury grade, and elevated SI were included in multivariate modeling. Grade of injury (OR 3.49, P=0.001), age (OR 1.02, P=0.009), and high SI (OR 3.49, P=0.001) were each independently significant for NIM failure. The risk-adjusted odds of failure were significantly higher in patients with a high risk SI (OR 2.35, P<0.001). Validation of these findings was confirmed for high SI on a subsequent 406 patients with a c-statistic of 0.71 (95% CI 0.62-0.80). Elevated SI is an independent risk factor for failure of NIM in those with splenic injury. SI along with age and computed tomography findings may aid in predicting the failure of NIM. Trauma providers should incorporate SI into decision-making tools for splenic injury management.