Faculty Collaboration Database

Sample entropy predicts lifesaving interventions in trauma patients with normal vital signs. J Crit Care 2015 Aug;30(4):705-10

Date

04/11/2015

Pubmed ID

25858820

DOI

10.1016/j.jcrc.2015.03.018

Scopus ID

2-s2.0-84930761876 (requires institutional sign-in at Scopus site)   8 Citations

Abstract

INTRODUCTION: Heart rate complexity, commonly described as a "new vital sign," has shown promise in predicting injury severity, but its use in clinical practice is not yet widely adopted. We previously demonstrated the ability of this noninvasive technology to predict lifesaving interventions (LSIs) in trauma patients. This study was conducted to prospectively evaluate the utility of real-time, automated, noninvasive, instantaneous sample entropy (SampEn) analysis to predict the need for an LSI in a trauma alert population presenting with normal vital signs.

METHODS: Prospective enrollment of patients who met criteria for trauma team activation and presented with normal vital signs was conducted at a level I trauma center. High-fidelity electrocardiogram recording was used to calculate SampEn and SD of the normal-to-normal R-R interval (SDNN) continuously in real time for 2 hours with a portable, handheld device. Patients who received an LSI were compared to patients without any intervention (non-LSI). Multivariable analysis was performed to control for differences between the groups. Treating clinicians were blinded to results.

RESULTS: Of 129 patients enrolled, 38 (29%) received 136 LSIs within 24 hours of hospital arrival. Initial systolic blood pressure was similar in both groups. Lifesaving intervention patients had a lower Glasgow Coma Scale. The mean SampEn on presentation was 0.7 (0.4-1.2) in the LSI group compared to 1.5 (1.1-2.0) in the non-LSI group (P < .0001). The area under the curve with initial SampEn alone was 0.73 (95% confidence interval [CI], 0.64-0.81) and increased to 0.93 (95% CI, 0.89-0.98) after adding sedation to the model. Sample entropy of less than 0.8 yields sensitivity, specificity, negative predictive value, and positive predictive value of 58%, 86%, 82%, and 65%, respectively, with an overall accuracy of 76% for predicting an LSI. SD of the normal-to-normal R-R interval had no predictive value.

CONCLUSIONS: In trauma patients with normal presenting vital signs, decreased SampEn is an independent predictor of the need for LSI. Real-time SampEn analysis may be a useful adjunct to standard vital signs monitoring. Adoption of real-time, instantaneous SampEn monitoring for trauma patients, especially in resource-constrained environments, should be considered.

Author List

Naraghi L, Mejaddam AY, Birkhan OA, Chang Y, Cropano CM, Mesar T, Larentzakis A, Peev M, Sideris AC, Van der Wilden GM, Imam AM, Hwabejire JO, Velmahos GC, Fagenholz PJ, Yeh D, de Moya MA, King DR

Author

Marc Anthony De Moya MD Chief, Professor in the Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Blood Pressure
Case-Control Studies
Critical Illness
Electrocardiography
Entropy
Female
Glasgow Coma Scale
Heart Rate
Humans
Male
Middle Aged
Prognosis
Prospective Studies
Respiration, Artificial
Sensitivity and Specificity
Trauma Centers
Trauma Severity Indices
Vital Signs
Wounds and Injuries