Modified Shock Index as a Predictor of Admission and In-hospital Mortality in Emergency Departments; an Analysis of a US National Database

Introduction

The modified shock index (MSI) is the ratio of heart rate to mean arterial pressure. It is used as a predictive and prognostic marker in a variety of disease states. This study aimed to derive the optimal MSI cut-off that is associated with increased likelihood (likelihood ratio, LR) of admission and in-hospital mortality in patients presenting to emergency department (ED).

Methods

We retrospectively reviewed data from the National Hospital Ambulatory Medical Care Survey between 2005 and 2010. Adults>18 years of age were included regardless of chief complaint. Basic patient demographics, initial vital signs, and outcomes were recorded for each patient. Then the optimal MSI cut-off for prediction of admission and in-hospital mortality in ED was calculated. LR ≥ 5 was considered clinically significant.

Results

567,994,402 distinct weighted adult ED patient visits were included in the analysis. 15.7% and 2.4% resulted in admissions and in-hospital mortality, respectively. MSI > 1.7 was associated with a moderate increase in the likelihood of both admission (Positive LR (+LR) = 6.29) and in-hospital mortality (+LR = 5.12). +LR for hospital admission at MSI >1.7 was higher for men (7.13; 95% CI 7.11-7.15) compared to women (5.49; 95% CI 5.47-5.50) and for non-white (7.92; 95% CI 7.88-7.95) compared to white patients (5.85; 95% CI 5.84-5.86). For MSI <0.7, the +LRs were not clinically significant for admission (+LR = 1.07) or in-hospital mortality (LR = 0.75).

Conclusion

In this largest retrospective study, to date, on MSI in the undifferentiated ED population, we demonstrated that an MSI >1.7 on presentation is predictive of admission and in-hospital mortality. The use of MSI could help guide accurate acuity designation, resource allocation, and disposition.

Evaluation of SI, MSI and DSI for very early (3-day) mortality in patients with septic shock

BACKGROUND

Septic shock is associated with increased mortality. Predicting mortality, including early prediction for septic shock patients in intensive care units (ICUs), remains an important challenge.

METHOD

We searched the Medical Information Mart for Intensive Care IV database. Odds ratios (ORs) with 95% confidence intervals (CIs) of the relationships between shock index (SI), modified SI (MSI), and diastolic SI (DSI) of patients with septic shock requiring vasopressors and 3-day/in-hospital mortality were calculated using logistic regression models. The time-course changes of these parameters were compared between survivors and non-survivors. The performance of the different parameters was described by the area under the receiver operating characteristic (ROC) curve (AUC) and compared with DeLong analysis.

RESULTS

A total of 1266 patients with septic shock requiring vasopressors were identified. The 3-day mortality rate and in-hospital mortality rate were 8.7% and 23.5%, respectively. Multivariable logistic regression analysis showed significant associations between pre-vasopressor SI/MSI/DSI and 3-day mortality in patients with septic shock requiring vasopressors in fully adjusted models (Ps for trend < 0.01). The AUCs of pre-vasopressor SI, MSI, and DSI were 0.746, 0.710, and 0.732 for 3-day mortality, respectively. There were significant differences in the time-course of SI, MSI, and DSI between survivors and non-survivors at 3-day/in-hospital mortality among patients with septic shock requiring vasopressors (repeated-measures ANOVA, inter-subjects difference P < 0.001).

CONCLUSION

Pre-vasopressor SI, MSI, and DSI values identified patients with septic shock requiring vasopressors who are at increased risk of early death. Of these easy-to-acquire values, SI and MSI show a comparatively better performance.

Modified Shock Index as a Predictor for Mortality and Hospitalization Among Patients With Dementia

BACKGROUND

One in four older adults in the Emergency Department (ED) suffers from severe cognitive impairment, creating great difficulty for the emergency physicians who determine the urgency of their patients' condition, which informs decisions regarding discharge or hospitalization.

OBJECTIVE

Our objective was to determine whether modified shock index (MSI) can be a clinical mortality and hospitalization predictor when applied to older patients with dementia in the ED.

METHODS

Included in the research were all patients with dementia, > 65 years old, who arrived at the Soroka University Medical Center ED during 2014-2017. The population was divided into three groups according to their MSI score, calculated as heart rate/mean arterial pressure: MSI < 0.7; 0.7 > MSI < 1.3; and MSI > 1.3. We performed multivariable logistic regression as a predictor of death within 30 days, Cox analysis for number of days to death, and a negative binominal regression for predicting the number of admission days.

RESULTS

Included were 1437 patients diagnosed with dementia. Patients with an MSI > 1.3 vs. those with MSI < 0.7 had an odds ratio of 8.23 (95% confidence interval [CI] 4.64-4.54) for mortality within 30 days, increased mortality risk within 180 days (hazard ratio 4.42; 95% CI 2.64-7.41), and longer hospitalization duration (incidence rate ratio 1.8; 95% CI 1.32-2.45).

CONCLUSIONS

High MSI scores were associated with high mortality rates and longer hospitalization duration for patients diagnosed with dementia who were > 65 years old. We suggest performing prospective studies utilizing the MSI score as an indicator in ED triage settings to classify patients with dementia by their severity of risk, to determine if this benefits health, minimizes expenses, and prevents unnecessary hospitalizations.

Use of age shock index in determining severity of illness in patients presenting to the emergency department with gastrointestinal bleeding

OBJECTIVES

This study aimed to make a comparison between classical shock index (SI), modified shock index (MSI), and age shock index (age SI) for predicting critical patients presenting to the emergency department (ED) with gastrointestinal bleeding (GIS).

METHODS

The study, which was planned retrospectively, consisted of patients diagnosed with GIS bleeding at the ED admission. Triage time vital signs were used to calculate SI, MSI, and age SI. These results were compared with intensive care admission, endoscopic/colonoscopic (E/C) intervention, blood transfusion, and mortality criteria, which we define as adverse outcomes.

RESULTS

The study included 151 patients. Seventy-nine (52.32%) of the patients had at least one adverse outcome. Of the 151 patients, 19 (12.58%) had ICU admission, 27 (17.88%) underwent endoscopic/colonoscopic (E/C) intervention, 68 (45.03%) received a blood transfusion, and 6 (3.97%) died. There was a significant difference between patients who had no adverse outcome and those who had at least one adverse outcome in terms of SI, age SI, and MSI. We performed ROC curve analyses to evaluate the diagnostic performances of all indices for predicting adverse outcomes. AUC (area under the curve) values for age SI was the highest (age SI AUC = 0.711, p < 0.001; SI AUC = 0.616; MSI AUC = 0.617). The performance of the age SI was significantly higher than the SI (p = 0.013) and the MSI (p = 0.024) for predicting adverse outcomes. The cut-off value for the age shock index was 45.12.

CONCLUSIONS

In patients with GIS bleeding, age SI, which can be easily calculated in triage, is more significant than SI and MSI for predicting the critical patient.

Shock index and modified shock index as triage screening tools for sepsis

BACKGROUND

Fever is one of the common conditions encountered in the emergency department, which related to a spectrum of diseases severity. Identifying sepsis patients from uncomplicated febrile patients is challenging in the emergency triage areas and pre-hospital settings.

OBJECTIVES

Assess the triage shock index (SI) and modified shock index (MSI) in febrile patients as predictors for sepsis and sepsis-related outcomes.

DESIGN

A retrospective cohort study.

SETTING

Patients presented to the Emergency Department of King Khalid University Hospital.

PATIENTS AND METHODS

The analysis included all febrile adult patients triaged with a temperature of 38 °C or more from January 2016 to December 2017. Based on triage vital sign we calculate the SI with cut-off levels of ≥0.7 and ≥1 and MSI with cut-off levels of ≥1 and ≥1.3. We report the Relative Risk, Sensitivity, Specificity, Positive and Negative Predictive Values of the predictors.

MAIN OUTCOME MEASURES

Sepsis and sepsis-related outcomes such as hyperlactatemia, ICU admission, and 28 days mortality.

SAMPLE SIZE

274 patients.

RESULTS

274 patients met our inclusion/exclusion criteria. Of the 274 patients, 252 patient (92%) were septic, 62 patients (22%) had hyperlactatemia, 20 patients admitted to the ICU, and 5 patient died within 28 days. An MSI of ≥1 had a sensitivity of 90% for sepsis predication, 85% for ICU admission and 100% for 28 days mortality. MSI of ≥1.3 showed a specificity (59%-100%) for all the outcomes of interest. Non-significant statistical trends of greater accuracy of MSI over SI.

CONCLUSION

MSI and SI were found to be promising predictors in triaging febrile patients. However no single cut-off values of MSI or SI were found to have an optimal accuracy for prediction of sepsis and sepsis-related outcomes. Further studies are required to assess the incorporation of MSI in a multi-item scaling system for the prediction of sepsis and its related outcomes.

LIMITATIONS

Small single center study and the results may not be generalizable.

Prehospital shock index, modified shock index, and pulse pressure heart rate ratio as predictors of massive blood transfusions in modern warfare injuries: A retrospective analysis

Background

Massive hemorrhage is the leading preventable cause of death in modern warfare injuries. Early and accurate detection of source of hemorrhage and massive blood transfusions remain the mainstay of management in such cases. Hemodynamic indices like shock index (SI), modified shock index (MSI), and pulse pressure heart rate (PP/HR) ratio have shown promising results in predicting massive transfusion in trauma patients. The present study aimed at assessing the accuracy of SI, MSI, and PP/HR ratio to predict the requirement of massive blood transfusions.

Methods

A retrospective analysis was done from 1st January 2016 to 31st December 2016 of the data taken from the trauma register of our hospital. Data were analyzed, and scores of SI, MSI, and PP/HR ratio were evaluated using area under receiver operating curves (AUROCs). Massive transfusion was defined as requirement of ≥10 packed red blood cells (PRBCs) in the first 24 hours or ≥4 PRBCs in first hour of hospital admission.

Results

Of the 326 warfare casualties received, a total of 254 patients were enrolled, and 51(23%) patients required massive transfusion on arrival. SI had an AUROC value of 0.798 (95% confidence interval [CI] = 0.739-0.848) which is comparable to MSI at 0.787 (95% CI = 0.728-0.839) and PP/HR ratio with a value of 0.744 (95% CI = 0.681-0.800), (p<0.001).

Conclusion

SI, MSI, and PP/HR ratio are equally efficient in predicting massive transfusion in warfare injuries and can be used as rapidly available marker for prediction of massive transfusion in warfare injuries which can be lifesaving and time-saving.

Modified shock index: A bedside clinical index for risk assessment of ST-segment elevation myocardial infarction at presentation

INTRODUCTION

Prompt identification of higher-risk patients presenting with ST-segment elevation myocardial infarction (STEMI) is crucial to pursue a more aggressive approach.

OBJECTIVE

We aimed to assess whether the modified shock index (MSI), the ratio of heart rate to mean arterial pressure, could predict six-month mortality among patients admitted with STEMI.

METHODS

A retrospective observational cohort study was performed in a single center including 1158 patients diagnosed with STEMI, without cardiogenic shock on admission, between July 2009 and December 2014. They were divided into two groups: group 1 - patients with MSI<0.93 (72%); group 2 - patients with MSI≥0.93 (28%). The primary endpoint was six-month all-cause mortality.

RESULTS

MSI≥0.93 identified patients who were more likely to have signs of heart failure (p=0.002), anemia (p<0.001), renal insufficiency (p=0.014) and left ventricular systolic dysfunction (p=0.045). They more often required inotropic support (p<0.001), intra-aortic balloon pump (p<0.001) and mechanical ventilation (p<0.001). Regarding in-hospital adverse events, they had a higher prevalence of malignant arrhythmias (p=0.01) and mechanical complications (p=0.027). MSI≥0.93 was an independent predictor of overall six-month mortality (adjusted HR 2.00, 95% CI 1.20-3.34, p=0.008).

CONCLUSION

MSI was shown to be a valuable bedside tool which can rapidly identify high-risk STEMI patients at presentation.

Correlation of shock index and modified shock index with the outcome of adult trauma patients: a prospective study of 9860 patients

BACKGROUND

Triage at emergency department is performed to identify those patients who are relatively more serious and require immediate attention and treatment. Despite current methods of triage, trauma continues to be a leading cause of morbidity and mortality.

AIMS

This study was to evaluate the predictive value of shock index (SI) and modified shock index (MSI) for hospital mortality among adult trauma patients.

MATERIALS AND METHODS

In this prospective longitudinal study, all adult patients who sustained trauma enrolled as per as inclusion/exclusion criteria. After the collection of data, SI and MSI were calculated accordingly. All parameters were again recorded hourly and calculations were done at six-hour intervals. Further, to achieve a value that can be analyzed, we determined threshold value for vital signs, which set the threshold values as heart rate at 120 beats per minute, systolic blood pressure at less than 90, and SI at cut-off 0.5-0.9 and MSI at less than 0.7 to more than 1.3.

RESULTS

We analyzed 9860 adult trauma patients. Multivariate regression analysis demonstrated that heart rate more than 120 beats per minute, systolic blood pressure less than 90 mmHg, and diastolic blood pressure (DBP) less than 60 mmHg correlate with hospital stay and mortality rate. MSI <0.7 and >1.3 had higher odds of mortality as compared to other predictors.

CONCLUSIONS

MSI is an important marker for predicting the mortality rate and is significantly better than heart rate, systolic blood pressure, DBP and SI alone. Therefore, modified SI should be used in the triage of serious patients, including trauma patients in the emergency room.

Modified shock index and mortality rate of emergency patients

BACKGROUND

This study aimed to determine whether modified shock index (MSI) is associated with mortality that is superior to heart rate, blood pressure, or the shock index (SI) in emergency patients.

METHODS

A retrospective database review was performed on 22 161 patients who presented to Peking Union Medical College Hospital Emergency Department and received intravenous fluids from January 1 to December 31, 2009. We gathered data of the patients on age, gender, vital signs, levels of consciousness, presenting complaints, and SI and MSI were calculated for all patients.

RESULTS

Multivariate regression analysis was performed to determine the correlation between risk factors and outcome. There is a significant correlation between emergency patient mortality rate and patient's vital signs obtained at the triage desk (HR>120 beats/min, systolic BP<90 mmHg, diastolic BP<60 mmHg). MSI is a stronger predictor of emergency patient mortality compared to heart rate and blood pressure alone, whereas SI does not have a significant correlation with emergency patient mortality rate.

CONCLUSION

MSI is a clinically significant predictor of mortality in emergency patients. It may be better than using heart rate and blood pressure alone. SI is not significantly correlated with the mortality rate of the emergency patient.