Norepinephrine plus dobutamine versus epinephrine alone for management of septic shock: a randomised trial

Statistics Myth Busters: Dispelling Common Misperceptions Held by Readers of the Biomedical Literature

Proficiency in research design and statistical analysis is crucial to the success of a clinical pharmacist. However, new pharmacy graduates and residents may not have received adequate training and education in these areas. During the authors' tenure as clinical pharmacists, several statistical "myths" were consistently maintained by residents and new clinical practitioners. The purpose of this narrative review is to discuss and dispel several of these statistical fallacies. The myths discussed involve 3 common areas of consideration when evaluating any clinical study: assessing the risk of bias from confounding (propensity score analysis and multivariable modeling), interpretation of the main study findings ( P values and hypothesis testing), and secondary evaluations (subgroup analyses). Literature examples are used to illustrate each of the topics. The authors hope that the discussion will augment each pharmacist's knowledge of medical literature interpretation leading to improvements in patient care, education of future residents, and personal research endeavors.

The management of intra-abdominal infections from a global perspective: 2017 WSES guidelines for management of intra-abdominal infections

Intra-abdominal infections (IAIs) are common surgical emergencies and have been reported as major contributors to non-trauma deaths in the emergency departments worldwide. The cornerstones of effective treatment of IAIs are early recognition, adequate source control, and appropriate antimicrobial therapy. Prompt resuscitation of patients with ongoing sepsis is of utmost important. In hospitals worldwide, non-acceptance of, or lack of access to, accessible evidence-based practices and guidelines result in overall poorer outcome of patients suffering IAIs. The aim of this paper is to promote global standards of care in IAIs and update the 2013 WSES guidelines for management of intra-abdominal infections.

Impact of Norepinephrine Weight-Based Dosing Compared With Non–Weight-Based Dosing in Achieving Time to Goal Mean Arterial Pressure in Obese Patients With Septic Shock

Background: Currently, a lack of standardization exists in norepinephrine dosing units, the first-line vasopressor for septic shock. Timely achievement of goal mean arterial pressure (MAP) is dependent on optimal vasopressor dosing. Objective: To determine if weight-based dosing (WBD) of norepinephrine leads to earlier time to goal MAP compared with non-WBD in obese patients with septic shock. Methods: This was a retrospective, multicenter cohort study. Patients had a body mass index (BMI) ≥30 kg/m2 and received norepinephrine for septic shock with either a non-WBD strategy (between December 2009 and January 2013) or WBD strategy (between January 2013 and December 2015). The primary outcome was time to goal MAP. Secondary outcomes were norepinephrine duration, dose requirements, and development of treatment-related complications. Results: A total of 287 patients were included (WBD 144; non-WBD 143). There was no difference in median time to goal MAP (WBD 58 minutes, interquartile range [IQR] = 16.8-118.5, vs non-WBD 60 minutes, IQR = 17.5-193.5; P = 0.28). However, there was a difference in median cumulative norepinephrine dose (WBD 12.6 mg, IQR = 4.9-45.9, vs non-WBD 10.5 mg, IQR = 3.9-25.6; P = 0.04) and time to norepinephrine discontinuation (WBD 33 hours, IQR = 15-69, vs non-WBD 27 hours, IQR = 12-51; P = 0.03). There was no difference in rates of atrial fibrillation (WBD 15.3% vs non-WBD 23.7%; P = 0.07) or mortality (WBD 23.6% vs non-WBD 23.1%; P = 0.92). Conclusion: WBD of norepinephrine does not achieve time to goal MAP earlier in obese patients with septic shock. However, WBD may lead to higher norepinephrine cumulative dose requirements and prolonged time until norepinephrine discontinuation.

Cerebral Blood Flow Autoregulation in Sepsis for the Intensivist: Why Its Monitoring May Be the Future of Individualized Care

Cerebral blood flow (CBF) autoregulation maintains consistent blood flow across a range of blood pressures (BPs). Sepsis is a common cause of systemic hypotension and cerebral dysfunction. Guidelines for BP management in sepsis are based on historical concepts of CBF autoregulation that have now evolved with the availability of more precise technology for its measurement. In this article, we provide a narrative review of methods of monitoring CBF autoregulation, the cerebral effects of sepsis, and the current knowledge of CBF autoregulation in sepsis. Current guidelines for BP management in sepsis are based on a goal of maintaining mean arterial pressure (MAP) above the lower limit of CBF autoregulation. Bedside tools are now available to monitor CBF autoregulation continuously. These data reveal that individual BP goals determined from CBF autoregulation monitoring are more variable than previously expected. In patients undergoing cardiac surgery with cardiopulmonary bypass, for example, the lower limit of autoregulation varied between a MAP of 40 to 90 mm Hg. Studies of CBF autoregulation in sepsis suggest patients frequently manifest impaired CBF autoregulation, possibly a result of BP below the lower limit of autoregulation, particularly in early sepsis or with sepsis-associated encephalopathy. This suggests that the present consensus guidelines for BP management in sepsis may expose some patients to both cerebral hypoperfusion and cerebral hyperperfusion, potentially resulting in damage to brain parenchyma. The future use of novel techniques to study and clinically monitor CBF autoregulation could provide insight into the cerebral pathophysiology of sepsis and offer more precise treatments that may improve functional and cognitive outcomes for survivors of sepsis.

Vasoactive agents for the treatment of sepsis

The article describes some commonly used vasoactive agents in patients with septic shock. Depending on their distinct pharmacological properties, their effects on vascular bed and cardiac function are different. For example, dopamine has equivalent effect on heart and vasculature, which can result in increases in cardiac output, mean arterial pressure and heart rate. Dobutamine is considered as inodilator because it has potent effect on cardiac systole and vasculature. Patients with sepsis and septic shock sometimes have coexisting cardiac dysfunction that justifies the use of dobutamine. Levosimendan is a relatively new agent exerting its inodilator effect by increasing sensitivity of myocardium to calcium. Some preliminary studies showed a promising result of levosimendan on reducing mortality.

Control groups in recent septic shock trials: a systematic review

PURPOSE

The interpretation of septic shock trial data is profoundly affected by patients, control intervention, co-interventions and selected outcome measures. We evaluated the reporting of control groups in recent septic shock trials.

METHODS

We searched for original articles presenting randomized clinical trials (RCTs) in adult septic shock patients from 2006 to 2016. We included RCTs focusing on septic shock patients with at least two parallel groups and at least 50 patients in the control group. We selected and evaluated data items regarding patients, control group characteristics, and mortality outcomes, and calculated a data completeness score to provide an overall view of quality of reporting.

RESULTS

A total of 24 RCTs were included (mean n = 287 patients and 71 % of eligible patients were randomized). Of the 24 studies, 14 (58 %) presented baseline data on vasopressors and 58 % the proportion of patients with elevated lactate values. Five studies (21 %) provided data to estimate the proportion of septic shock patients fulfilling the Sepsis-3 definition. The mean data completeness score was 19 out of 36 (range 8-32). Of 18 predefined control group characteristics, a mean of 8 (range 2-17) were reported. Only 2 (8 %) trials provided adequate data to confirm that their control group treatment represented usual care.

CONCLUSIONS

Recent trials in septic shock provide inadequate data on the control group treatment and hemodynamic values. We propose a standardized trial dataset to be created and validated, comprising characteristics of patient population, interventions administered, hemodynamic values achieved, surrogate organ dysfunction, and mortality outcomes, to allow better analysis and interpretation of future trial results.

Genomics and pharmacogenomics of sepsis: so close and yet so far

Sapru et al. show in this issue of Critical Care that variants of thrombomodulin and the endothelial protein C receptor, but not protein C, are associated with mortality and organ dysfunction (ventilation-free and organ failure-free days) in ARDS. Hundreds of gene variants have been found prognostic in sepsis. However, none of these prognostic genomic biomarkers are used clinically. Predictive biomarker discovery (pharmacogenomics) usually follows a candidate gene approach, utilizing knowledge of drug pathways. Pharmacogenomics could be applied to enhance efficacy and safety of drugs used for treatment of sepsis (e.g., norepinephrine, epinephrine, vasopressin, and corticosteroids). Pharmacogenomics can enhance drug development in sepsis, which is very important because there is no approved drug for sepsis. Pharmacogenomics biomarkers must pass three milestones: scientific, regulatory, and commercial. Huge challenges remain but great opportunities for pharmacogenomics of sepsis are on the horizon.

Comparative Effectiveness of Second Vasoactive Agents in Septic Shock Refractory to Norepinephrine

OBJECTIVE

We aim to identify the appropriate vasoactive agent in patients with septic shock who are refractory to optimal doses of norepinephrine.

METHODS

In this retrospective observational cohort study over a 4-year period, patients who received norepinephrine within 24 hours of ICU admission and a second agent within 48 hours were enrolled.

RESULTS

Among 2640 patients screened, 234 patients were enrolled, aged 60.8 ± 17.8 years, Acute Physiology and Chronic Health Evaluation IV 98.3 ± 27.5, 81.6% mechanically ventilated, and 65.8% in-hospital mortality. Within 96 hours, 2.8 ± 1.0 vasoactive agents were administered. Fifty, 50, 66, and 68 patients received dobutamine, dopamine, phenylephrine, and vasopressin as the second agent, with crude in-hospital mortality 40.0%, 66.0%, 74.2%, and 76.5%, respectively, P < .001. Survival analysis showed a statistically significant difference in survival time by second vasoactive agent, P < .001. After adjusting for confounding variables, dobutamine showed significant decreased odds ratio (OR) for mortality compared to vasopressin: OR 0.34 (95% confidence interval 0.14-0.84, P = .04). The relative risk of dying was 55.8% lower in patients receiving dobutamine versus vasopressin, P < .01.

CONCLUSION

Dobutamine is associated with decreased mortality compared to other second vasoactive agents in septic shock when norepinephrine is not sufficient. A prospective randomized trial examining the outcome impact of the second vasoactive agent is needed.

Comparative safety and efficacy of vasopressors for mortality in septic shock: A network meta-analysis

INTRODUCTION

Septic shock is a life-threatening condition requiring vasopressor agents to support the circulatory system. Several agents exist with choice typically guided by the specific clinical scenario. We used a network meta-analysis approach to rate the comparative efficacy and safety of vasopressors for mortality and arrhythmia incidence in septic shock patients.

METHODS

We performed a comprehensive electronic database search including Medline, Embase, Science Citation Index Expanded and the Cochrane database. Randomised trials investigating vasopressor agents in septic shock patients and specifically assessing 28-day mortality or arrhythmia incidence were included. A Bayesian network meta-analysis was performed using Markov chain Monte Carlo methods.

RESULTS

Thirteen trials of low to moderate risk of bias in which 3146 patients were randomised were included. There was no pairwise evidence to suggest one agent was superior over another for mortality. In the network meta-analysis, vasopressin was significantly superior to dopamine (OR 0.68 (95% CI 0.5 to 0.94)) for mortality. For arrhythmia incidence, standard pairwise meta-analyses confirmed that dopamine led to a higher incidence of arrhythmias than norepinephrine (OR 2.69 (95% CI 2.08 to 3.47)). In the network meta-analysis, there was no evidence of superiority of one agent over another.

CONCLUSIONS

In this network meta-analysis, vasopressin was superior to dopamine for 28-day mortality in septic shock. Existing pairwise information supports the use of norepinephrine over dopamine. Our findings suggest that dopamine should be avoided in patients with septic shock and that other vasopressor agents should continue to be based on existing guidelines and clinical judgement of the specific presentation of the patient.

Potential drug-drug interactions in a medical intensive care unit of a university hospital

BACKGROUND/AIM

Drug-drug interactions (DDIs) can impact patient safety. Occurrence of clinically important DDIs is higher for intensive care unit (ICU) patients. This observational study aimed to evaluate the potential DDIs in medical ICU patients of a university hospital.

MATERIALS AND METHODS

The Medical Pharmacology Department organized consultation reports for ICU patients in order to detect the DDIs. To focus on clinically important DDIs, interactions in the C, D, or X risk rating categories of the Lexi-Interact online database were analyzed. Frequency and clinical risk rating categories of DDIs were detected. Relationship between number of prescriptions and DDIs were assessed. The most frequent drug/drug groups were identified.

RESULTS

Of 101 ICU patients, 45.5% were found to have DDIs. We detected 125 C (72.2%), 37 D (21.4%), and 11 X (6.4%) risk category interactions. A statistically significant increase in the number of DDIs was shown with the number of prescriptions (P = 0.002). The most frequent DDIs were between agents acting on the cardiovascular system and corticosteroids (12.8%).

CONCLUSION

Results of this study show that pharmacological consultation plays a critical role in the recognition of DDIs for improvement of medication management and effective therapeutic endpoints without any adverse or toxic reactions.

Vasopressors for hypotensive shock

BACKGROUND

Initial goal-directed resuscitation for hypotensive shock usually includes administration of intravenous fluids, followed by initiation of vasopressors. Despite obvious immediate effects of vasopressors on haemodynamics, their effect on patient-relevant outcomes remains controversial. This review was published originally in 2004 and was updated in 2011 and again in 2016.

OBJECTIVES

Our objective was to compare the effect of one vasopressor regimen (vasopressor alone, or in combination) versus another vasopressor regimen on mortality in critically ill participants with shock. We further aimed to investigate effects on other patient-relevant outcomes and to assess the influence of bias on the robustness of our effect estimates.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015 Issue 6), MEDLINE, EMBASE, PASCAL BioMed, CINAHL, BIOSIS and PsycINFO (from inception to June 2015). We performed the original search in November 2003. We also asked experts in the field and searched meta-registries to identify ongoing trials.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing various vasopressor regimens for hypotensive shock.

DATA COLLECTION AND ANALYSIS

Two review authors abstracted data independently. They discussed disagreements between them and resolved differences by consulting with a third review author. We used a random-effects model to combine quantitative data.

MAIN RESULTS

We identified 28 RCTs (3497 participants) with 1773 mortality outcomes. Six different vasopressors, given alone or in combination, were studied in 12 different comparisons.All 28 studies reported mortality outcomes; 12 studies reported length of stay. Investigators reported other morbidity outcomes in a variable and heterogeneous way. No data were available on quality of life nor on anxiety and depression outcomes. We classified 11 studies as having low risk of bias for the primary outcome of mortality; only four studies fulfilled all trial quality criteria.In summary, researchers reported no differences in total mortality in any comparisons of different vasopressors or combinations in any of the pre-defined analyses (evidence quality ranging from high to very low). More arrhythmias were observed in participants treated with dopamine than in those treated with norepinephrine (high-quality evidence). These findings were consistent among the few large studies and among studies with different levels of within-study bias risk.

AUTHORS' CONCLUSIONS

We found no evidence of substantial differences in total mortality between several vasopressors. Dopamine increases the risk of arrhythmia compared with norepinephrine and might increase mortality. Otherwise, evidence of any other differences between any of the six vasopressors examined is insufficient. We identified low risk of bias and high-quality evidence for the comparison of norepinephrine versus dopamine and moderate to very low-quality evidence for all other comparisons, mainly because single comparisons occasionally were based on only a few participants. Increasing evidence indicates that the treatment goals most often employed are of limited clinical value. Our findings suggest that major changes in clinical practice are not needed, but that selection of vasopressors could be better individualised and could be based on clinical variables reflecting hypoperfusion.

Adrenaline aggravates lung injury caused by liver ischemia-reperfusion and high-tidal-volume ventilation in rats

BACKGROUND

We often administer adrenaline to improve hypotension of patients undergoing systemic inflammation that is not treated with volume resuscitation. The effects of adrenaline on injured lungs during shock status have not been elucidated. We previously demonstrated that hepatic ischemia-reperfusion followed by high-tidal-volume ventilation-induced systemic inflammation, hypotension, and lung injury in rats. Using this animal model, we investigated the effects of adrenaline on lung injury and hemodynamics.

METHODS

Anesthetized rats were ventilated and underwent hepatic inflow interruption for 15 min twice. After the second liver ischemia-reperfusion, the tidal volume was increased to 24 ml · kg(-1) body weight from 6 ml · kg(-1), and 12 rats in each group were observed for 360 min after reperfusion with or without continuous intravenous adrenaline administration. Extra fluid was administered according to the decline in the arterial blood pressure.

RESULTS

Adrenaline administration significantly reduced the volume of intravenous resuscitation fluid. The wet-to-dry weight ratio of the lungs was higher (7.53 ± 0.37 vs. 4.63 ± 0.35, P < 0.001), the partial oxygen pressure in arterial blood was lower (213 ± 48 vs. 411 ± 33, P = 0.004), and the tumor necrosis factor-α concentration in bronchoalveolar lavage (BAL) fluid was higher (10(2.64) ± 10(0.22) vs. 10(1.91) ± 10(0.27), P = 0.015), with adrenaline. Histopathological examinations revealed marked exudation in the alveolar spaces in rats receiving adrenaline.

CONCLUSIONS

Continuous administration of adrenaline partially prevented a rapid decline in blood pressure but deteriorated lung injury in a rat model of liver ischemia-reperfusion with high-tidal-volume ventilation. A possibility that adrenaline administration aggravate ventilator-induced lung injury during systemic inflammation should be considered.

Challenges with Diagnosing and Managing Sepsis in Older Adults

Sepsis in older adults has many challenges that affect rate of septic diagnosis, treatment, and monitoring parameters. Numerous age-related changes and comorbidities contribute to increased risk of infections in older adults, but also atypical symptomatology that delays diagnosis. Due to various pharmacokinetic/pharmacodynamic changes in the older adult, medications are absorbed, metabolized, and eliminated at different rates as compared to younger adults, which increases risk of adverse drug reactions due to use of drug therapy needed for sepsis management. This review provides information to aid in diagnosis and offers recommendations for monitoring and treating sepsis in the older adult population.

Lactic Acidosis in Sepsis: It's Not All Anaerobic: Implications for Diagnosis and Management

Increased blood lactate concentration (hyperlactatemia) and lactic acidosis (hyperlactatemia and serum pH < 7.35) are common in patients with severe sepsis or septic shock and are associated with significant morbidity and mortality. In some patients, most of the lactate that is produced in shock states is due to inadequate oxygen delivery resulting in tissue hypoxia and causing anaerobic glycolysis. However, lactate formation during sepsis is not entirely related to tissue hypoxia or reversible by increasing oxygen delivery. In this review, we initially outline the metabolism of lactate and etiology of lactic acidosis; we then address the pathophysiology of lactic acidosis in sepsis. We discuss the clinical implications of serum lactate measurement in diagnosis, monitoring, and prognostication in acute and intensive care settings. Finally, we explore treatment of lactic acidosis and its impact on clinical outcome.

Outcome of inotropic therapy: is less always more?

PURPOSE OF REVIEW

Positive inotropic agents are widely used in the management of the critical ill patient presenting with low cardiac output state. Different inotropic agents are available, and different effects on hemodynamic endpoints may be recognized, but data on relevant clinical endpoints are scarce. A growing body of literature suggests that overuse of inotropes may have detrimental effects on cardiomyocytes, resulting in an increased risk of morbidity and mortality. The present review will summarize recent literature, focusing on outcome studies among adult patients related to use of inotropes in different clinical settings.

RECENT FINDINGS

Use of inotropic therapy shows a manifold variation between hospitals and individual providers even after risk standardization. No recent studies have shown inotropic therapy to provide short-term and long-term improvement of morbidity and mortality in patients with advanced nonsurgical heart failure or septic shock or as part of goal-directed treatment in high-risk noncardiac surgery. Levosimendan may show beneficial effect on mortality in cardiac surgery.

CONCLUSION

A 'less is more' approach may show to be appropriate when relating to routine use of inotropes. Inotropic therapy should be restricted to patients with heart failure and clinical signs of end-organ hypoperfusion.

Personalizing blood pressure management in septic shock

This review examines the available evidence for targeting a specific mean arterial pressure (MAP) in sepsis resuscitation. The clinical data suggest that targeting an MAP of 65-70 mmHg in patients with septic shock who do not have chronic hypertension is a reasonable first approximation. Whereas in patients with chronic hypertension, targeting a higher MAP of 80-85 mmHg minimizes renal injury, but it comes with increased risk of arrhythmias. Importantly, MAP alone should not be used as a surrogate of organ perfusion pressure, especially under conditions in which intracranial, intra-abdominal or tissue pressures may be elevated. Organ-specific perfusion pressure targets include 50-70 mmHg for the brain based on trauma brain injury as a surrogate for sepsis, 65 mmHg for renal perfusion and >50 mmHg for hepato-splanchnic flow. Even at the same MAP, organs and regions within organs may have different perfusion pressure and pressure-flow relationships. Thus, once this initial MAP target is achieved, MAP should be titrated up or down based on the measures of organ function and tissue perfusion.

Sepsis and ARDS: The Dark Side of Histones

Despite advances in management over the last several decades, sepsis and acute respiratory distress syndrome (ARDS) still remain major clinical challenges and the leading causes of death for patients in intensive care units (ICUs) due to insufficient understanding of the pathophysiological mechanisms of these diseases. However, recent studies have shown that histones, also known as chromatin-basic structure proteins, could be released into the extracellular space during severe stress and physical challenges to the body (e.g., sepsis and ARDS). Due to their cytotoxic and proinflammatory effects, extracellular histones can lead to excessive and overwhelming cell damage and death, thus contributing to the pathogenesis of both sepsis and ARDS. In addition, antihistone-based treatments (e.g., neutralizing antibodies, activated protein C, and heparin) have shown protective effects and have significantly improved the outcomes of mice suffering from sepsis and ARDS. Here, we review researches related to the pathological role of histone in context of sepsis and ARDS and evaluate the potential value of histones as biomarkers and therapeutic targets of these diseases.

Quantifying the improvement in sepsis diagnosis, documentation, and coding: the marginal causal effect of year of hospitalization on sepsis diagnosis

PURPOSE

To quantify the coinciding improvement in the clinical diagnosis of sepsis, its documentation in the electronic health records, and subsequent medical coding of sepsis for billing purposes in recent years.

METHODS

We examined 98,267 hospitalizations in 66,208 patients who met systemic inflammatory response syndrome criteria at a tertiary care center from 2008 to 2012. We used g-computation to estimate the causal effect of the year of hospitalization on receiving an International Classification of Diseases, Ninth Revision, Clinical Modification discharge diagnosis code for sepsis by estimating changes in the probability of getting diagnosed and coded for sepsis during the study period.

RESULTS

When adjusted for demographics, Charlson-Deyo comorbidity index, blood culture frequency per hospitalization, and intensive care unit admission, the causal risk difference for receiving a discharge code for sepsis per 100 hospitalizations with systemic inflammatory response syndrome, had the hospitalization occurred in 2012, was estimated to be 3.9% (95% confidence interval [CI], 3.8%-4.0%), 3.4% (95% CI, 3.3%-3.5%), 2.2% (95% CI, 2.1%-2.3%), and 0.9% (95% CI, 0.8%-1.1%) from 2008 to 2011, respectively.

CONCLUSIONS

Patients with similar characteristics and risk factors had a higher of probability of getting diagnosed, documented, and coded for sepsis in 2012 than in previous years, which contributed to an apparent increase in sepsis incidence.

Shock Management for Cardio-surgical ICU Patients - The Golden Hours

Postoperative shock following cardiac surgery is a serious condition with a high morbidity and mortality. There are four types of shock: cardiogenic, hypovolemic, obstructive and distributive and these can occur alone or in combination. Early identification of the underlying diseases and understanding of the mechanisms at play are key for successful management of shock. Prompt resuscitation measures are necessary to reverse the shock state and avoid permanent organ dysfunction or death. In this review, the authors focus on the management during the first 6 hours of shock (the 'golden hours'). They discuss how to optimise preload, vascular tone, contractility, heart rate and oxygen delivery. The review incorporates the findings of recent trials on early goal-directed therapy and includes practical recommendations in areas in which the evidence is scare or controversial. While the review focuses on cardio-surgical patients, the suggested treatment algorithms might be usefully expanded to other critically ill patients with shock arising from other causes.

Impact of endotracheal intubation on septic shock outcome: A post hoc analysis of the SEPSISPAM trial

INTRODUCTION

The objective of the study to is to determine the characteristics associated with endotracheal intubation in septic shock patients.

METHODS

This is a post hoc analysis of the database of the SEPSISPAM study, including patients with septic shock.

RESULTS

Among the 776 patients, 633 (82%) were intubated within 12 hours of study inclusion (early intubation), 113 (15%) were never intubated, and 30 (4%) had delayed intubation. Intensive care units (ICUs) were classified according to frequency of early intubation: early intubation less than 80% of patients (lowest frequency: 7 ICUs, 254 patients), 80% to 90% (middle frequency: 5 ICUs, 170 patients), and greater than 90% (highest frequency: 6 ICUs, 297 patients). Type of ICU, pulmonary infection, lactate greater than 2 mmol/L, lower Pao2/fraction of inspired oxygen ratio, lower Glasgow score, and absence of immunosuppression were independently associated with early intubation. Patients never intubated had a lower initial severity and a low mortality rate. In comparison to patients intubated early, patients with delayed intubation had had fewer days alive without organ support by day 28. Intensive care units with the highest frequency of early intubation had a higher mortality rate in comparison to ICUs with middle frequency of early intubation. A nonsignificant increased mortality was observed in ICU with lowest frequency of early intubation.

CONCLUSIONS

Practices regarding the place of endotracheal intubation in septic shock may impact outcome.

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 for the Treatment of Septic Shock: Systematic Review and Meta-Analysis

Objective

International guidelines recommend dopamine or norepinephrine as first-line vasopressor agents in septic shock. Phenylephrine, epinephrine, vasopressin and terlipressin are considered second-line agents. Our objective was to assess the evidence for the efficiency and safety of all vasopressors in septic shock.

Methods

Systematic review and meta-analysis. We searched electronic database of MEDLINE, CENTRAL, LILACS and conference proceedings up to June 2014. We included randomized controlled trials comparing different vasopressors for the treatment of adult patients with septic shock. Primary outcome was all-cause mortality. Other clinical and hemodynamic measurements were extracted as secondary outcomes. Risk ratios (RR) and mean differences with 95% confidence intervals (CI) were pooled.

Results

Thirty-two trials (3,544 patients) were included. Compared to dopamine (866 patients, 450 events), norepinephrine (832 patients, 376 events) was associated with decreased all-cause mortality, RR 0.89 (95% CI 0.81-0.98), corresponding to an absolute risk reduction of 11% and number needed to treat of 9. Norepinephrine was associated with lower risk for major adverse events and cardiac arrhythmias compared to dopamine. No other mortality benefit was demonstrated for the comparisons of norepinephrine to epinephrine, phenylephrine and vasopressin / terlipressin. Hemodynamic data were similar between the different vasopressors, with some advantage for norepinephrine in central venous pressure, urinary output and blood lactate levels.

Conclusions

Evidence suggests a survival benefit, better hemodynamic profile and reduced adverse events rate for norepinephrine over dopamine. Norepinephrine should be regarded as the first line vasopressor in the treatment of septic shock.

Implementation of standardized dosing units for i.v. medications

PURPOSE

The implementation of standardized dosing units for six i.v. medications at an academic medical center is described.

SUMMARY

During the implementation of an electronic health record system at an academic medical center, it was noticed that providers could order some i.v. medications in multiple dosing units, including epinephrine, isoproterenol, midazolam, nitroglycerin, norepinephrine, and phenylephrine. Possible options to standardize i.v. medications along with their pros and cons were presented for discussion to key providers in all of the intensive care units. Once the providers agreed on a solution, the information was presented to the pharmacy and therapeutics committee for final approval. A nursing education plan was created and administered before the standardization of dosing units was implemented. A nursing survey was conducted before and after implementation of dosing-unit standardization to determine the effectiveness of nursing education on compliance with the standardization of the dosing units for the listed medications. The survey was designed to evaluate, when given a choice, what dosing units nurses would use to administer epinephrine, isoproterenol, midazolam, nitroglycerin, norepinephrine, and phenylephrine. The decision was made by the key providers to use weight-based dosing-micrograms per kilograms per minute-to allow for consistency of use of these medications for pediatric and adult patients. Nursing education was completed to ensure that nurses were aware of how to safely administer these medications using the new dosing units.

CONCLUSION

Dosing-unit standardization for dose-adjustable i.v. infusions can provide improved consistency and decrease the potential for dosing errors when administering epinephrine, isoproterenol, midazolam, nitroglycerin, norepinephrine, and phenylephrine.

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.

Current concepts on hemodynamic support and therapy in septic shock

Severe sepsis and septic shock represent a major healthcare challenge. Much of the improvement in mortality associated with septic shock is related to early recognition combined with timely fluid resuscitation and adequate antibiotics administration. The main goals of septic shock resuscitation include intravascular replenishment, maintenance of adequate perfusion pressure and oxygen delivery to tissues. To achieve those goals, fluid responsiveness evaluation and complementary interventions - i.e. vasopressors, inotropes and blood transfusion - may be necessary. This article is a literature review of the available evidence on the initial hemodynamic support of the septic shock patients presenting to the emergency room or to the intensive care unit and the main interventions available to reach those targets, focusing on fluid and vasopressor therapy, blood transfusion and inotrope administration.

Does the Mean Arterial Pressure Influence Mortality Rate in Patients with Acute Hypoxemic Respiratory Failure under Mechanical Ventilation?

Background

In sepsis patients, target mean arterial pressures (MAPs) greater than 65 mm Hg are recommended. However, there is no such recommendation for patients receiving mechanical ventilation. We aimed to evaluate the influence of MAP over the first 24 hours after intensive care unit (ICU) admission on the mortality rate at 60 days post-admission in patients showing acute hypoxemic respiratory failure under mechanical ventilation.

Methods

This prospective, multicenter study included 22 ICUs and compared the mortality and clinical outcomes in patients showing acute hypoxemic respiratory failure with high (75-90 mm Hg) and low (65-74.9 mm Hg) MAPs over the first 24 hours of admission to the ICU.

Results

Of the 844 patients with acute hypoxemic respiratory failure, 338 had a sustained MAP of 65-90 mm Hg over the first 24 hours of admission to the ICU. At 60 days, the mortality rates in the low (26.2%) and high (24.5%) MAP groups were not significantly different. The ICU days, hospital days, and 60-day mortality rate did not differ between the groups.

Conclusion

In the first 24 hours of ICU admission, MAP range between 65 and 90 mm Hg in patients with acute hypoxemic respiratory failure under mechanical ventilation may not cause significantly differences in 60-day mortality.

[Catecholamines: pro and contra]

BACKGROUND

Catecholamines with vasopressor and inotropic effects are commonly used in intensive care medicine. The aim of this review is to explain some of the physiologic actions on which a catecholamine therapy is based, but also to elucidate the risks which are associated with an uncritical and excessive use of these drugs.

SIDE EFFECTS

Emphasis is placed on the myocardial damage triggered by adrenergic overstimulation. There is considerable evidence that in conditions of severe heart failure, myocardial ischemia as well as cardiogenic and septic shock especially the use of catecholamines with predominant β-adrenergic effects (epinephrine, dobutamine, dopamine) can have a negative clinical impact. A simple cardiac risk marker might be a tachycardia.

ADMINISTRATION

Vasopressor therapy with norepinephrine, based on individually applied perfusion parameters (e.g., urine output, lactate), however, seems justified in many conditions of shock and hemodynamic instability during deep analgosedation. In terms of a cardioprotective therapy, the administration of catecholamines, however, should always be reevaluated and titrated to the minimum deemed necessary.

Vascular Dilation, Tachycardia, and Increased Inotropy Occur Sequentially with Increasing Epinephrine Dose Rate, Plasma and Myocardial Concentrations, and cAMP

BACKGROUND

While epinephrine infusion is widely used in critical care for inotropic support, there is no direct method to detect the onset and measure the magnitude of this response. We hypothesised that surrogate measurements, such as heart rate and vascular tone, may indicate if the plasma and tissue concentrations of epinephrine and cAMP are in a range sufficient to increase myocardial contractility.

METHODS

Cardiovascular responses to epinephrine infusion (0.05-0.5 mcgkg(-1)min(-1)) were measured in rats using arterial and left ventricular catheters. Epinephrine and cAMP levels were measured using ELISA techniques.

RESULTS

The lowest dose of epinephrine infusion (0.05 mcgkg(-1)min(-1)) did not raise plasma epinephrine levels and did not lead to cardiovascular response. Incremental increase in epinephrine infusion (0.1 mcgkg(-1)min(-1)) elevated plasma but not myocardial epinephrine levels, providing vascular, but not cardiac effects. Further increase in the infusion rate (0.2 mcgkg(-1)min(-1)) raised myocardial tissue epinephrine levels sufficient to increase heart rate but not contractility. Inotropic and lusitropic effects were significant at the infusion rate of 0.3 mcgkg(-1)min(-1). Correlation of plasma epinephrine to haemodynamic parameters suggest that as plasma concentration increases, systemic vascular resistance falls (EC50=47 pg/ml), then HR increases (ED50=168 pg/ml), followed by a rise in contractility and lusitropy (ED50=346 pg/ml and ED50=324 pg/ml accordingly).

CONCLUSIONS

The dose response of epinephrine is distinct for vascular tone, HR and contractility. The need for higher doses to see cardiac effects is likely due to the threshold for drug accumulation in tissue. Successful inotropic support with epinephrine cannot be achieved unless the infusion is sufficient to raise the heart rate.

New directions for sepsis and septic shock research

BACKGROUND

Septic shock is a frequent complication in intensive care unit that can result in multiple organ failure and death. In addition, recent data suggested that severe sepsis and septic shock represent an economic burden. Therefore, septic shock is an important public health problem.

METHOD

In this review, we will focus on the recent evidences concerning the stages of septic shock, the complex macrocirculation and microcirculation relationship, and the importance of those evidences for future resuscitation goals and therapeutic strategies during late septic shock.

RESULT

Recently, two stages of septic shock are suggested. In early stage, hypovolemia is the main contributing factor. During this stage, macrocirculatory and microcirculatory changes run parallel, and fluid resuscitation seems to be effective in restoring the hemodynamic parameters. Late stage of septic shock is characterized by complex microcirculation and macrocirculation relationship.

CONCLUSIONS

Although early goal-directed therapy is a stepwise approach in the treatment of septic shock, tissue perfusion remains an important factor that contributes to septic shock outcome. Because appropriate monitoring of tissue perfusion is a matter of debt, the ideal therapeutic strategy remains a controversial issue that needs further investigations.

Pharmacotherapy Update on the Use of Vasopressors and Inotropes in the Intensive Care Unit

This paper summarizes the pharmacologic properties of vasoactive medications used in the treatment of shock, including the inotropes and vasopressors. The clinical application of these therapies is discussed and recent studies describing their use and associated outcomes are also reported. Comprehension of hemodynamic principles and adrenergic and non-adrenergic receptor mechanisms are salient to the appropriate therapeutic utility of vasoactive medications for shock. Vasoactive medications can be classified based on their direct effects on vascular tone (vasoconstriction or vasodilation) and on the heart (presence or absence of positive inotropic effects). This classification highlights key similarities and differences with respect to pharmacology and hemodynamic effects. Vasopressors include pure vasoconstrictors (phenylephrine and vasopressin) and inoconstrictors (dopamine, norepinephrine, and epinephrine). Each of these medications acts as vasopressors to increase mean arterial pressure by augmenting vascular tone. Inotropes include inodilators (dobutamine and milrinone) and the aforementioned inoconstrictors. These medications act as inotropes by enhancing cardiac output through enhanced contractility. The inodilators also reduce afterload from systemic vasodilation. The relative hemodynamic effect of each agent varies depending on the dose administered, but is particularly apparent with dopamine. Recent large-scale clinical trials have evaluated vasopressors and determined that norepinephrine may be preferred as a first-line therapy for a broad range of shock states, most notably septic shock. Consequently, careful selection of vasoactive medications based on desired pharmacologic effects that are matched to the patient's underlying pathophysiology of shock may optimize hemodynamics while reducing the potential for adverse effects.

Cognitive decline after sepsis

The modern era of sepsis management is characterised by a growing number of patients who survive in the short term and are discharged from hospital. Increasing evidence suggests that these survivors exhibit long-term neurological sequelae, particularly substantial declines in cognitive function. The exact prevalence and outcomes of these neuropsychological sequelae are unclear. The mechanisms by which sepsis induces cognitive dysfunction probably include vascular injuries and neuroinflammation that are mediated by systemic metabolism disorders and overwhelming inflammation, a disrupted blood-brain barrier, oxidative stress, and severe microglial activation, particularly within the limbic system. Interventions targeting the blood-brain barrier, glial activation, and oxidative stress have shown promise in prevention of cognitive dysfunction in various experimental models of sepsis. The next step should be to translate these favourable effects into positive clinical results.

Early management of severe sepsis: concepts and controversies

Sepsis is among the most common reasons for admission to ICUs throughout the world, and it is believed to be the third most common cause of death in the United States. The pathogenetic mechanism and physiologic changes associated with sepsis are exceedingly complex, but our understanding is evolving rapidly. The major pathophysiologic changes in patients with septic shock include vasoplegic shock (distributive shock), myocardial depression, altered microvascular flow, and a diffuse endothelial injury. These pathophysiologic changes play a central role in the management of sepsis. The early management of patients with severe sepsis and septic shock centers on the administration of antibiotics, IV fluids, and vasoactive agents, followed by source control. However, the specific approach to the resuscitation of patients with septic shock remains highly controversial. This review provides a practical and physiologic-based approach to the early management of sepsis and explores the controversies surrounding the management of this complex condition.

Physicians declining patient enrollment in a critical care trial: a case study in thromboprophylaxis

PURPOSE

To analyze the frequency, rationale and determinants of attending physicians requesting that their eligible patients not be approached for participation in a thromboprophylaxis trial.

METHODS

Research personnel in 67 centers prospectively documented eligible non-randomized patients due to physicians declining to allow their patients to be approached.

RESULTS

In 67 centers, 3,764 patients were enrolled, but 1,460 eligible patients had no consent encounter. For 218 (14.9 %) of these, attending physicians requested that their patients not be approached. The most common reasons included a high risk of bleeding (31.2 %) related to fear of heparin bioaccumulation in renal failure, the presence of an epidural catheter, peri-operative status or other factors; specific preferences for thromboprophylaxis (12.4 %); morbid obesity (9.6 %); uncertain prognosis (6.4 %); general discomfort with research (3.7 %) and unclear reasons (17.0 %). Physicians were more likely to decline when approached by less experienced research personnel; considering those with[10 years of experience as the reference category, the odds ratios (OR) for physician refusals to personnel without trial experience was 10.47 [95 % confidence interval (CI) 2.19-50.02] and those with less than 10 years experience was 1.72 (95 % CI 0.61-4.84). Physicians in open rather than closed units were more likely to decline (OR 4.26; 95 % CI 1.27-14.34). Refusals decreased each year of enrollment compared to the pilot phase.

CONCLUSIONS

Tracking, analyzing, interpreting and reporting the rates and reasons for physicians declining to allow their patients to be approached for enrollment provides insights into clinicians' concerns and attitudes to trials. This information can encourage physician communication and education, and potentially enhance efficient recruitment.