The shock index predicts acute mortality outcomes in stroke

Heart-Rate-to-Blood-Pressure Ratios Correlate with Malignant Brain Edema and One-Month Death in Large Hemispheric Infarction: A Cohort Study

INTRODUCTION

Large hemispheric infarction (LHI) can lead to fatal complications such as malignant brain edema (MBE). We aimed to investigate the correlation between heart-rate-to-blood-pressure ratios and MBE or one-month death after LHI.

METHODS

We prospectively included LHI patients from a registered cohort. Hourly heart-rate-to-blood-pressure ratios were recorded as a variation of the traditional shock index (SI), SIs and SId (systolic and diastolic pressures, respectively), and calculated for mean and variability (standard deviation) in 24 h and two 12 h epochs (1-12 h and 13-24 h) after onset of symptoms. MBE was defined as neurological deterioration symptoms with imaging evidence of brain swelling. We employed a generalized estimating equation to compare the trend in longitudinal collected SIs and SId between patients with and without MBE. We used multivariate logistic regression to investigate the correlation between SIs, SId and outcomes.

RESULTS

Of the included 162 LHI patients, 28.4% (46/162) developed MBE and 25.3% (40/158) died within one month. SIs and SId increased over baseline in all patients, with a similar ascending profile during the first 12 h epoch and a more intensive increase in the MBE group during the second 12 h epoch (p < 0.05). During the overall 24 h, patients with greater SId variability had a significantly increased MBE risk after adjustment (OR 3.72, 95%CI 1.38-10.04). Additionally, during the second 12 h epoch (13-24 h after symptom onset), patients developing MBE had a significantly higher SId level (OR 1.18, 95%CI 1.00-1.39) and greater SId variability (OR 3.16, 95%CI 1.35-7.40). Higher SId and greater SId variability within 24 h independently correlated with one-month death (all p < 0.05). Within the second 12 h epoch, higher SIs, higher SId and greater SId variability independently correlated with one-month death (all p < 0.05). No significant correlation was observed in the first 12 h epoch.

CONCLUSIONS

Higher and more fluctuated heart-rate-to-blood-pressure ratios independently correlated with MBE development and one-month death in LHI patients, especially during the second 12 h (13-24 h) epoch after onset.

The relationship between age shock index, and severity of stroke and in-hospital mortality in patients with acute ischemic stroke

BACKGROUND

Shock index (SI) has been reported to help us predict adverse prognosis in patients with acute ischemic stroke (AIS). However, the prognostic value of age SI and age modified shock index (MSI) in acute ischemic stroke is unknown. In our study, we aimed to examine the association between the severity of the stroke and in-hospital mortality, age SI and age MSI in patients with AIS.

METHODS

A total of 256 patients were enrolled in this study. The National Institutes of Health Stroke Scale (NIHSS) was used to determine the severity of stroke. Patients were divided into two groups according to the NIHSS score calculated during hospitalization (NIHSS>14: severe disability group, NIHSS<15: moderate and mild disability group). Shock indexes were calculated using the blood pressure and heart rate values measured as a result of the cardiovascular examinations of the patients. We looked for correlations between increased NIHSS and in-hospital mortality with age shock index and age modified shock index.

RESULTS

Age SI and age MSI values were higher in the severe disability group than those without severe disability, and the results were statistically significant (p<0.001, p<0.001, respectively). Also, a positive correlation was determined between the height of NIHSS and the age SI and the age MSI (p=0.002, r=0.197, p=0.001, r=0.215, respectively). Thirty-two (12.5%) of 256 patients included in the study died during hospitalization. Patients who died were older (77.1±11.0 vs. 67.5±13.5, respectively; p<0.001). According to Point-Biserial correlation analysis, there was a positive correlation between mortality and age SI, and age MSI (p<0.001, r=0.258 ve p<0.001, r=0.274, respectively).

CONCLUSIONS

As a result of our study, the relationship between stroke severity and increasing age SI and age MSI was significant and there was a positive correlation. In addition, there was a significant and positive relationship between in-hospital mortality and age SI and age MSI.

Shock index predicts up to 90-day mortality risk after intracerebral haemorrhage

BACKGROUND

Shock index (SI - heart rate/systolic blood pressure) has been studied as a measure of haemodynamic status. We aimed to determine whether SI measures within 72 h of admission were associated with adverse outcomes in intracerebral haemorrhage (ICH).

METHODS

Patients were drawn from the Virtual International Stroke Trials Archive-Intracerebral Haemorrhage (VISTA-ICH). Multivariable Cox regressions modelled the relationship between SI (on admission, 24, 48, 72 h) and mortality (at 3-, 7-, and 90-days), 90-day incident pneumonia and cardiovascular events (MACE). Ordinal logistic regressions modelled the relationship between SI and 90-day modified Rankin Scale (mRS).

RESULTS

979 patients were included. Baseline SI was not associated with mortality. 24 h SI > 0.7 was associated with 7-day mortality (hazard ratio (95% confidence interval) = 3.14 (1.37-7.19)). 48 h and 72 h SI > 0.7 were associated with 7-day (4.23 (2.07-8.66) and 3.24 (1.41-7.42) respectively) and 90-day mortality (2.97 (1.82-4.85) and 2.05 (1.26-3.61) respectively). SI < 0.5 at baseline, 48 h and 72 h was associated with decreased pneumonia risk. 24 h and 48 h SI > 0.7was associated with increased MACE risk. 48 h and 72 h SI > 0.7 was associated with increased odds of higher 90-day mRS.

CONCLUSION

Higher-than-normal SI subsequent to initial encounter was associated with higher post-ICH mortality at 3, 7, and 90 days. Lower-than-normal SI was associated with a decreased risk of incident pneumonia.

In-hospital mortality of acute pulmonary embolism: Predictive value of shock index, modified shock index, and age shock index scores

OBJECTIVE

The shock index (SI), modified shock index (MSI), and age shock index (ASI) have been reported to predict adverse outcomes in patients with different acute cardiovascular conditions. This study aimed to investigate the association between these indexes and in-hospital mortality in patients with acute pulmonary embolism.

METHODS

The medical records of all adult patients who were hospitalized with acute pulmonary embolism between June 2014 and June 2019, were examined. Collected data included vital signs, demographic characteristics, comorbidities, and laboratory values on presentation. The predictive value of SI, MSI, ASI, and pulmonary embolism severity index (PESI) for predicting in-hospital mortality were compared by C-statistics.

RESULTS

A total of 602 consecutive patients (mean age 66.7±13.2 years, 55% female) were included, and 62 (10.3%) of the patients died during their in-hospital course. The admission SI, MSI, ASI, and PESI were significantly higher in the deceased patients. After adjusting for other factors, the SI, MSI, PESI, and ASI were independent predictors of in-hospital mortality. The prognostic performance of ASI (C-statistics 0.74) was better than MSI (C-statistics 0.71), SI (C-statistics 0.68), and PESI (C-statistics 0.65).

CONCLUSION

The ASI may be used to identify patients at risk for in-hospital mortality following acute pulmonary embolism.

Modified early warning score and risk of mortality after acute stroke

OBJECTIVE

An accurate prediction tool may facilitate optimal management of patients with acute stroke from an early stage. We evaluated the association between admission modified early warning score (MEWS) and mortality in patients with acute stroke.

METHOD

Data from the Anglia Stroke Clinical Network Evaluation Study (ASCNES) were analysed. We evaluated the association between admission MEWS and four outcomes; in-patient, 7-day, 30-day and 1-year mortality. Logistic regression models were used to calculate the odds of all mortality timeframes, whereas Cox proportional hazards models were used to calculate mortality at 1 year. Five univariate and multivariate models were constructed, adjusting for confounders. Patients with a moderate (2-3) or high (≥4) scores were compared to patients with a low score (0-1).

RESULTS

The study population consisted of 2006 patients. A total of 1196 patients had low MEWS, 666 had moderate MEWS and 144 had a high MEWS. A high MEWS was associated with increased mortality as an in-patient (OR 4.93, 95 % CI: 2.88-8.42), at 7 days (OR 7.53, 95 % CI: 4.24-13.38), at 30 days (OR 5.74, 95 % CI: 3.38-9.76) and 1-year (HR 2.52, 95 % CI 1.88-3.39). At 1 year, model 5 had a 1.02 OR (95 % CI 0.83-1.24) with moderate MEWS and 2.52 (95 % CI 1.88-3.39) with high MEWS.

CONCLUSION

Elevated MEWS on admission is a potential marker for acute-stroke mortality and may therefore be a useful risk prediction tool, able to guide clinicians attempting to prognosticate outcomes for patients with acute-stroke.

Equivalency between the shock index and subtracting the systolic blood pressure from the heart rate: an observational cohort study

Background

Although the shock index is known to predict mortality and other severe outcomes, deriving it requires complex calculations. Subtracting the systolic blood pressure from the heart rate may produce a simple shock index that would be a clinically useful substitute for the shock index. In this study, we investigated whether the simple shock index was equivalent to the shock index.

Methods

This observational cohort study was conducted at 2 tertiary care hospitals. Patients who were transported by ambulance were recruited for this study and were excluded if they were aged < 15 years, had experienced prehospital cardiopulmonary arrest, or had undergone inter-hospital transfer. Pearson’s product-moment correlation coefficient and regression equation were calculated, and two one-sided tests were performed to examine their equivalency.

Results

Among 5429 eligible patients, the correlation coefficient between the shock index and simple shock index was extremely high (0.917, 95% confidence interval 0.912 to 0.921, P < .001). The regression equation was estimated as sSI = 258.55 log SI. The two one-sided tests revealed a very strong equivalency between the shock index and the index estimated by the above equation using the simple shock index (mean difference was 0.004, 90% confidence interval 0.003 to 0.005).

Conclusion

The simple shock index strongly correlated with the shock index.

The use of the shock index to predict hemodynamic collapse in hypotensive sepsis patients: A cross-sectional analysis

Objectives:

Septic shock, defined as sepsis with hypotension not responding to fluid resuscitation or requiring vasopressor support, results in the worst outcomes in sepsis patients. This subtype of the patient is often difficult to detect. The shock index (SI) has demonstrated the potential for predicting hemodynamic compromise and collapse and predicting patient outcomes in multiple medical and surgical settings. In our study, we assessed the utility of the SI as a hemodynamic screening tool to identify patients likely to fail to respond to fluids and ultimately to be diagnosed with septic shock.

Methodology:

A single-center cross-sectional analysis of patients presenting with hypotension and septicemia over 1 year. The study was conducted using the electronic medical records of the emergency department patients presenting to King Saud University Medical City. The charts were reviewed from 2 May 2015 to 24 April 2016 using the local medical registry. The study was approved by the hospital institutional review board (IRB). Data extraction was performed using a standardized form.

Results:

The area under the curve was 0.77 (P < 0.001) for the prediction of hemodynamic collapse. An initial SI ≥0.875 had a sensitivity of 81% and a specificity of 72% for the identification of patients in whom fluid resuscitation would fail.

Conclusions:

Based on our findings, we found that the SI was a reliable screening tool for the identification of hypotensive patients with sepsis who would ultimately be diagnosed with septic shock.

Shock Index Predicts Patient-Related Clinical Outcomes in Stroke

Background

The prognostic value of shock index (SI), heart rate divided by systolic blood pressure, in stroke for clinical outcomes other than mortality is not well understood.

Methods and Results

We examined the Get With The Guidelines–Stroke (GWTG‐Stroke) data to explore the usefulness of SI in predicting in‐hospital outcomes in 425 808 acute stroke cases (mean age: 71.0±14.5 years; 48.8% male; 89.7% ischemic stroke and 10.3% intracerebral hemorrhage) admitted between October 2012 and March 2015. Compared with patients with SI of 0.5 to 0.7, patients with SI >0.7 (13.6% of the sample) had worse outcomes, with adjusted odds ratios of 2.00 (95% confidence interval [CI], 1.92–2.08) for in‐hospital mortality, 1.46 (95% CI, 1.43–1.49) for longer length of hospital stay >4 days, 1.50 (95% CI, 1.47–1.54) for discharge destination other than home, 1.41 (95% CI, 1.38–1.45) for inability to ambulate independently at discharge, and 1.52 (95% CI, 1.47–1.57) for modified Rankin Scale score of 3 to 6 at discharge. Results were similar when analyses were confined to those with available National Institutes of Health Stroke Scale (NIHSS) or within individual stroke subtypes or when SI was additionally included in the models with or without blood pressure components. Every 0.1 increase in SI >0.5 was associated with significantly worse outcomes in linear spline models. The addition of SI to existing GWTG‐Stroke mortality prediction models without NIHSS demonstrated modest improvement, but little to no improvement was noted in models with NIHSS.

Conclusions

SI calculated at the point of care may be a useful prognostic indicator to identify those with high risk of poor outcomes in acute stroke, especially in hospitals with limited experience with NIHSS assessment.

Optimal Hemodynamic Parameter to Predict the Neurological Outcome in Out-of-Hospital Cardiac Arrest Survivors Treated with Target Temperature Management

Current guidelines suggest the maintenance of systolic blood pressure (SBP) at >90 mmHg and mean arterial pressure (MAP) at >65 mmHg in postcardiac arrest patients. There remains a lack of clarity regarding optimal values and timing of blood pressure parameters associated with the improvement of neurologic outcome. We investigated the association of time-weighted average (TWA) blood pressure parameters with favorable neurological outcome (FO) in postcardiac arrest patients. This was a registry-based observational study with consecutive adult out-of-hospital cardiac arrest (OHCA) survivors who were treated using targeted temperature management (TTM). During 72 hours of TTM period, we abstracted hemodynamic parameters such as SBP, diastolic blood pressure, pulse rate (PR), and MAP. Shock index (SI; PR/SBP) and modified shock index (MSI; PR/MAP) were calculated from each measured hemodynamics. Logistic regression was performed to assess the associations between TWA blood pressure parameters and FO, defined as cerebral performance category 1 or 2 at hospital discharge. Among the 173 patients (median age: 58 years; 64% male), 51 (29.3%) had FO in this study. MAP, SI, and MSI at 6 hours after return of spontaneous circulation (ROSC) showed considerable differences in patients with FO (MAP: 89.1 ± 14.7 vs. 83.6 ± 15.8 mmHg, p = 0.033, SI: 0.7 ± 0.2 vs. 0.9 ± 0.9, p = 0.002, MSI: 1.0 ± 0.3 vs. 1.2 ± 0.3, p ≤ 0.001). Among them, MSI, especially at 6 hours, had the highest area under the curve for prediction of FO (0.685; 95% confidence interval: 0.597-0.772, p < 0.001). Also, MSI <1.0 had a sensitivity of 64.7%, a specificity of 64.2% to predict FO. In comatose survivors of OHCA with TTM, MSI at 6 hours after ROSC had the highest prognostic value for neurologic outcome among blood pressure parameters.

Systolic blood pressure lower than the heart rate indicates a poor outcome in patients with severe isolated traumatic brain injury: A cross-sectional study

BACKGROUND

A systolic blood pressure (SBP) lower than the heart rate (HR) could indicate a poor condition in trauma patients. In such scenarios, the reversed shock index (RSI) is < 1, as calculated by the SBP divided by the HR. This study aimed to clarify whether RSI could be used to identify high-risk adult patients with isolated traumatic brain injury (TBI).

METHODS

This retrospective study reviewed 1216 hospitalized adult patients with isolated TBI at a Level I trauma center between January 1, 2009 and December 31, 2015. The patients were grouped and analyzed according to RSI (<1 or ≥ 1). Subgroups of patients with severe TBI (Glasgow Coma Scale [GCS] ≤ 8) or non-severe TBI (GCS > 8) were also compared. The primary outcome was in-hospital mortality. The odds ratios (ORs) of categorical variables were calculated by chi-square tests with 95% confidence intervals (CIs). Mann-Whitney U-tests were used to analyze non-normally distributed continuous data.

RESULTS

Among patients with isolated TBI, those with an RSI <1 had higher mortality (44.7% vs. 7.1%, OR: 10.5, 95% CI: 5.36-20.75; P < 0.001) than those with an RSI ≥1. An RSI <1 indicated a higher risk of mortality (OR: 5.1, 95% CI: 2.08-12.49; P < 0.001) in patients with severe isolated TBI but not in patients with non-severe isolated TBI (OR: 3.6, 95% CI: 0.45-28.71; P = 0.267).

CONCLUSION

Patients with isolated TBI may be at risk for shock. In trauma patients with severe isolated TBI, an SBP lower than the HR indicates a poor outcome.