Timing of vasopressor initiation and mortality in septic shock: a cohort study

How to avoid fluid overload

PURPOSE OF REVIEW

This review highlights the recent evidence describing the outcomes associated with fluid overload in critically ill patients and provides an overview of fluid management strategies aimed at preventing fluid overload during the resuscitation of patients with shock.

RECENT FINDINGS

Fluid overload is a common complication of fluid resuscitation and is associated with increased hospital costs, morbidity and mortality.

SUMMARY

Fluid management goals differ during the resuscitation, optimization, stabilization and evacuation phases of fluid resuscitation. To prevent fluid overload, strategies that reduce excessive fluid infusions and emphasize the removal of accumulated fluids should be implemented.

Automatic versus manual changeovers of norepinephrine infusion pumps in critically ill adults: a prospective controlled study

Background

Norepinephrine is a key drug for treating shock but has a short half-life that requires continuous intravenous administration to maintain the constant plasma concentration needed to obtain a stable blood pressure. The small volume of the syringes used in power infusion pumps requires frequent changeovers, which can lead to norepinephrine flow interruptions responsible for hemodynamic instability. Changeovers from the nearly empty to the full syringe can be performed manually using the quick change technique (QC) or automatically using smart infusion pumps (SIP) that link two syringes. The purpose of our study was to evaluate the hypothesis that, compared to QC, SIP for norepinephrine changeovers was associated with less hemodynamic instability.

Methods

After information of the patient or next of kin, patients receiving norepinephrine for shock were allocated to QC or SIP changeovers. QC changeovers were performed by a nurse, who started a new loaded pump when the previous syringe was nearly empty. SIP changeovers were managed automatically by SIP workstations. The primary outcome was the proportion of changeovers followed by a ≥20 % drop in mean arterial pressure (MAP).

Results

411 changeovers were performed, 193 in the 18 patients allocated to QC and 218 in the 32 patients allocated to SIP. Baseline patient characteristics were similar in both groups. The proportion of changeovers followed by an MAP drop ≥20 % was 12.4 % (24/193) with QC and 5.5 % (12/218) with SIP (P = 0.01). By multivariate analysis, two factors were independently associated with a significantly decreased risk of ≥20 % MAP drops during changeovers, namely, SIP (odds ratio, 0.47; 95 % confidence interval, 0.22–0.98) and norepinephrine dosage >0.5 μg/kg/min (odds ratio, 0.39; 95 % confidence interval, 0.19–0.81).

Conclusions

The risk of MAP drops ≥20 % during changeovers can be significantly diminished using SIPs instead of the QC method.

Trial registration: Clinicaltrial.gov NCT 01127152

Disparities in Adherence to Pediatric Sepsis Guidelines across a Spectrum of Emergency Departments: A Multicenter, Cross-Sectional Observational In Situ Simulation Study

BACKGROUND

Each year in the United States, 72,000 pediatric patients develop septic shock, at a cost of $4.8 billion. Adherence to practice guidelines can significantly reduce mortality; however, few methods to compare performance across a spectrum of emergency departments (EDs) have been described.

OBJECTIVES

We employed standardized, in situ simulations to measure and compare adherence to pediatric sepsis guidelines across a spectrum of EDs. We hypothesized that pediatric EDs (PEDs) would have greater adherence to the guidelines than general EDs (GEDs). We also explored factors associated with improved performance.

METHODS

This multi-center observational study examined in situ teams caring for a simulated infant in septic shock. The primary outcome was overall adherence to the pediatric sepsis guideline as measured by six subcomponent metrics. Characteristics of teams were compared using multivariable logistic regression to describe factors associated with improved performance.

RESULTS

We enrolled 47 interprofessional teams from 24 EDs. Overall, 21/47 teams adhered to all six sepsis metrics (45%). PEDs adhered to all six metrics more than GEDs (93% vs. 22%; difference 71%, 95% confidence interval [CI] 43-84). Adherent teams had significantly higher Emergency Medical Services for Children readiness scores, MD composition of physicians to total team members, teamwork scores, provider perceptions of pediatric preparedness, and provider perceptions of sepsis preparedness. In a multivariable regression model, only greater composite team experience had greater adjusted odds of achieving an adherent sepsis score (adjusted odds ratio 1.38, 95% CI 1.01-1.88).

CONCLUSIONS

Using standardized in situ scenarios, we revealed high variability in adherence to the pediatric sepsis guideline across a spectrum of EDs. PEDs demonstrated greater adherence to the guideline than GEDs; however, in adjusted analysis, only composite team experience level of the providers was associated with improved guideline adherence.

Development of metabolic and inflammatory mediator biomarker phenotyping for early diagnosis and triage of pediatric sepsis

Introduction

The first steps in goal-directed therapy for sepsis are early diagnosis followed by appropriate triage. These steps are usually left to the physician’s judgment, as there is no accepted biomarker available. We aimed to determine biomarker phenotypes that differentiate children with sepsis who require intensive care from those who do not.

Methods

We conducted a prospective, observational nested cohort study at two pediatric intensive care units (PICUs) and one pediatric emergency department (ED). Children ages 2–17 years presenting to the PICU or ED with sepsis or presenting for procedural sedation to the ED were enrolled. We used the judgment of regional pediatric ED and PICU attending physicians as the standard to determine triage location (PICU or ED). We performed metabolic and inflammatory protein mediator profiling with serum and plasma samples, respectively, collected upon presentation, followed by multivariate statistical analysis.

Results

Ninety-four PICU sepsis, 81 ED sepsis, and 63 ED control patients were included. Metabolomic profiling revealed clear separation of groups, differentiating PICU sepsis from ED sepsis with accuracy of 0.89, area under the receiver operating characteristic curve (AUROC) of 0.96 (standard deviation [SD] 0.01), and predictive ability (Q²) of 0.60. Protein mediator profiling also showed clear separation of the groups, differentiating PICU sepsis from ED sepsis with accuracy of 0.78 and AUROC of 0.88 (SD 0.03). Combining metabolomic and protein mediator profiling improved the model (Q² =0.62), differentiating PICU sepsis from ED sepsis with accuracy of 0.87 and AUROC of 0.95 (SD 0.01). Separation of PICU sepsis or ED sepsis from ED controls was even more accurate. Prespecified age subgroups (2–5 years old and 6–17 years old) improved model accuracy minimally. Seventeen metabolites or protein mediators accounted for separation of PICU sepsis and ED sepsis with 95 % confidence.

Conclusions

In children ages 2–17 years, combining metabolomic and inflammatory protein mediator profiling early after presentation may differentiate children with sepsis requiring care in a PICU from children with or without sepsis safely cared for outside a PICU. This may aid in making triage decisions, particularly in an ED without pediatric expertise. This finding requires validation in an independent cohort.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1026-2) contains supplementary material, which is available to authorized users.

Early goal-directed resuscitation of patients with septic shock: current evidence and future directions

Severe sepsis and septic shock are among the leading causes of mortality in the intensive care unit. Over a decade ago, early goal-directed therapy (EGDT) emerged as a novel approach for reducing sepsis mortality and was incorporated into guidelines published by the international Surviving Sepsis Campaign. In addition to requiring early detection of sepsis and prompt initiation of antibiotics, the EGDT protocol requires invasive patient monitoring to guide resuscitation with intravenous fluids, vasopressors, red cell transfusions, and inotropes. The effect of these measures on patient outcomes, however, remains controversial. Recently, three large randomized trials were undertaken to re-examine the effect of EGDT on morbidity and mortality: the ProCESS trial in the United States, the ARISE trial in Australia and New Zealand, and the ProMISe trial in England. These trials showed that EGDT did not significantly decrease mortality in patients with septic shock compared with usual care. In particular, whereas early administration of antibiotics appeared to increase survival, tailoring resuscitation to static measurements of central venous pressure and central venous oxygen saturation did not confer survival benefit to most patients. In the following review, we examine these findings as well as other evidence from recent randomized trials of goal-directed resuscitation. We also discuss future areas of research and emerging paradigms in sepsis trials.

Timing of antibiotics, volume, and vasoactive infusions in children with sepsis admitted to intensive care

INTRODUCTION

Early administration of antibiotics for sepsis, and of fluid boluses and vasoactive agents for septic shock, is recommended. Evidence for this in children is limited.

METHODS

The Alberta Sepsis Network prospectively enrolled eligible children admitted to the Pediatric Intensive Care Unit (PICU) with sepsis from 04/2012-10/2014. Demographics, severity of illness, and outcomes variables were prospectively entered into the ASN database after deferred consent. Timing of interventions were determined by retrospective chart review using a study manual and case-report-form. We aimed to determine the association of intervention timing and outcome in children with sepsis. Univariate (t-test and Fisher's Exact) and multiple linear regression statistics evaluated predictors of outcomes of PICU length of stay (LOS) and ventilation days.

RESULTS

Seventy-nine children, age median 60 (IQR 22-133) months, 40 (51%) female, 39 (49%) with severe underlying co-morbidity, 44 (56%) with septic shock, and median PRISM-III 10.5 [IQR 6.0-17.0] were enrolled. Most patients presented in an ED: 36 (46%) at an outlying hospital ED, and 21 (27%) at the Children's Hospital ED. Most infections were pneumonia with/without empyema (42, 53%), meningitis (11, 14%), or bacteremia (10, 13%). The time from presentation to acceptable antibiotic administration was a median of 115.0 [IQR 59.0-323.0] minutes; 20 (25%) of patients received their antibiotics in the first hour from presentation. Independent predictors of PICU LOS were PRISM-III, and severe underlying co-morbidity, but not time to antibiotics. In the septic shock subgroup, the volume of fluid boluses given in the first 2 hours was independently associated with longer PICU LOS (effect size 0.22 days; 95% CI 0.5, 0.38; per ml/kg). Independent predictors of ventilator days were PRISM-III score and severe underlying co-morbidity. In the septic shock subgroup, volume of fluid boluses in the first 2 hours was independently associated with more ventilator days (effect size 0.09 days; 95% CI 0.02, 0.15; per ml/kg).

CONCLUSION

Higher volume of early fluid boluses in children with sepsis and septic shock was independently associated with longer PICU LOS and ventilator days. More study on the benefits and harms of fluid bolus therapy in children are needed.

Vasopressors in septic shock: a systematic review and network meta-analysis

Objective

Vasopressor agents are often prescribed in septic shock. However, their effects remain controversial. We conducted a systematic review and Bayesian network meta-analysis to compare the effects among different types of vasopressor agents.

Data sources

We searched for relevant studies in PubMed, Embase, and the Cochrane Library databases from database inception until December 2014.

Study selection

Randomized controlled trials in adults with septic shock that evaluated different vasopressor agents were selected.

Data extraction

Two authors independently selected studies and extracted data on study characteristics, methods, and outcomes.

Data synthesis

Twenty-one trials (n=3,819) met inclusion criteria, which compared eleven vasopressor agents or vasopressor combinations (norepinephrine [NE], dopamine [DA], vasopressin [VP], epinephrine [EN], terlipressin [TP], phenylephrine [PE], TP+NE, TP + dobutamine [DB], NE+DB, NE+EN, and NE + dopexamine [DX]). Except for the superiority of NE over DA, the mortality of patients treated with any vasopressor agent or vasopressor combination was not significantly different. Compared to DA, NE was found to be associated with decreased cardiac adverse events, heart rate (standardized mean difference [SMD]: −2.10; 95% confidence interval [CI]: −3.95, −0.25; P=0.03), and cardiac index (SMD: −0.73; 95% CI: −1.14, −0.03; P=0.004) and increased systemic vascular resistance index (SVRI) (SMD: 1.03; 95% CI: 0.61, 1.45; P<0.0001). This Bayesian meta-analysis revealed a possible rank of probability of mortality among the eleven vasopressor agents or vasopressor combinations; from lowest to highest, they are NE+DB, EN, TP, NE+EN, TP+NE, VP, TP+DB, NE, PE, NE+DX, and DA.

Conclusion

In terms of survival, NE may be superior to DA. Otherwise, there is insufficient evidence to suggest that any other vasopressor agent or vasopressor combination is superior to another. When compared to DA, NE is associated with decreased heart rate, cardiac index, and cardiovascular adverse events, as well as increased SVRI. The effects of vasopressor agents or vasopressor combinations on mortality in patients with septic shock require further investigation.

Quality improvement in pediatric sepsis

PURPOSE OF REVIEW

Although there is abundant literature detailing the impact of quality improvement in adult sepsis, the pediatric literature is lacking. Despite consensus definitions for sepsis, which patients along the sepsis spectrum should receive aggressive management and the exact onset of sepsis ('time zero') are not clearly established. In the adult emergency department (ED), sepsis onset is defined as the time of entry into the ED; however, this definition cannot be applied to hospitalized patients or patients who evolve during their ED course. Since the time of sepsis onset will dictate the timeliness of subsequent process measures, the variable definitions in the literature make it difficult to generalize findings among prior studies.

RECENT FINDINGS

Despite the variation in defining time zero, aggressive fluid administration, timely antibiotics, and compliance with sepsis bundles have been shown to improve mortality and to reduce hospital and intensive care length of stay. In addition, early identification tools show promise in beginning to define sepsis onset and retrospective search tools may allow improved case finding of those children of concern for sepsis.

SUMMARY

Quality improvement in pediatric sepsis is evolving. As we continue to define quality measures, we must standardize the definition of sepsis onset. This definition should be applicable to any treatment venue to ensure measures can be evaluated across all settings. In addition, we must delineate which patients along the sepsis spectrum should be candidates for timely interventions and standardize other outcome measures beyond mortality.

The arterial blood pressure associated with terminal cardiovascular collapse in critically ill patients: a retrospective cohort study

Introduction

Liberal and overaggressive use of vasopressors during the initial period of shock resuscitation may compromise organ perfusion and worsen outcome. When transiently applying the concept of permissive hypotension, it would be helpful to know at which arterial blood pressure terminal cardiovascular collapse occurs.

Methods

In this retrospective cohort study, we aimed to identify the arterial blood pressure associated with terminal cardiovascular collapse in 140 patients who died in the intensive care unit while being invasively monitored. Demographic data, co-morbid conditions and clinical data at admission and during the 24 hours before and at the time of terminal cardiovascular collapse were collected. The systolic, mean and diastolic arterial blood pressures immediately before terminal cardiovascular collapse were documented. Terminal cardiovascular collapse was defined as an abrupt (<5 minutes) and exponential decrease in heart rate (>50% compared to preceding values) followed by cardiac arrest.

Results

The mean ± standard deviation (SD) values of the systolic, mean and diastolic arterial blood pressures associated with terminal cardiovascular collapse were 47 ± 12 mmHg, 35 ± 11 mmHg and 29 ± 9 mmHg, respectively. Patients with congestive heart failure (39 ± 13 mmHg versus 34 ± 10 mmHg; P = 0.04), left main stem stenosis (39 ± 11 mmHg versus 34 ± 11 mmHg; P = 0.03) or acute right heart failure (39 ± 13 mmHg versus 34 ± 10 mmHg; P = 0.03) had higher arterial blood pressures than patients without these risk factors. Patients with severe valvular aortic stenosis had the highest arterial blood pressures associated with terminal cardiovascular collapse (systolic, 60 ± 20 mmHg; mean, 46 ± 12 mmHg; diastolic, 36 ± 10 mmHg), but this difference was not significant. Patients with sepsis and patients exposed to sedatives or opioids during the terminal phase exhibited lower arterial blood pressures than patients without sepsis or administration of such drugs.

Conclusions

The arterial blood pressure associated with terminal cardiovascular collapse in critically ill patients was very low and varied with individual co-morbid conditions (for example, congestive heart failure, left main stem stenosis, severe valvular aortic stenosis, acute right heart failure), drug exposure (for example, sedatives or opioids) and the type of acute illness (for example, sepsis).

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0719-2) contains supplementary material, which is available to authorized users.

Dynamic arterial elastance as a predictor of arterial pressure response to fluid administration: a validation study

Introduction

Functional assessment of arterial load by dynamic arterial elastance (Ea_dyn), defined as the ratio between pulse pressure variation (PPV) and stroke volume variation (SVV), has recently been shown to predict the arterial pressure response to volume expansion (VE) in hypotensive, preload-dependent patients. However, because both SVV and PPV were obtained from pulse pressure analysis, a mathematical coupling factor could not be excluded. We therefore designed this study to confirm whether Ea_dyn, obtained from two independent signals, allows the prediction of arterial pressure response to VE in fluid-responsive patients.

Methods

We analyzed the response of arterial pressure to an intravenous infusion of 500 ml of normal saline in 53 mechanically ventilated patients with acute circulatory failure and preserved preload dependence. Ea_dyn was calculated as the simultaneous ratio between PPV (obtained from an arterial line) and SVV (obtained by esophageal Doppler imaging). A total of 80 fluid challenges were performed (median, 1.5 per patient; interquartile range, 1 to 2). Patients were classified according to the increase in mean arterial pressure (MAP) after fluid administration in pressure responders (≥10%) and non-responders.

Results

Thirty-three fluid challenges (41.2%) significantly increased MAP. At baseline, Ea_dyn was higher in pressure responders (1.04 ± 0.28 versus 0.60 ± 0.14; P <0.0001). Preinfusion Ea_dyn was related to changes in MAP after fluid administration (R² = 0.60; P <0.0001). At baseline, Ea_dyn predicted the arterial pressure increase to volume expansion (area under the receiver operating characteristic curve, 0.94; 95% confidence interval (CI): 0.86 to 0.98; P <0.0001). A preinfusion Ea_dyn value ≥0.73 (gray zone: 0.72 to 0.88) discriminated pressure responder patients with a sensitivity of 90.9% (95% CI: 75.6 to 98.1%) and a specificity of 91.5% (95% CI: 79.6 to 97.6%).

Conclusions

Functional assessment of arterial load by Ea_dyn, obtained from two independent signals, enabled the prediction of arterial pressure response to fluid administration in mechanically ventilated, preload-dependent patients with acute circulatory failure.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0626-6) contains supplementary material, which is available to authorized users.