beta-Blockers in sepsis: reexamining the evidence

Impact of norepinephrine on immunity and oxidative metabolism in sepsis

Sepsis is a major health problem in the United States (US), constituting a leading contributor to mortality among critically ill patients. Despite advances in treatment the underlying pathophysiology of sepsis remains elusive. Reactive oxygen species (ROS) have a significant role in antimicrobial host defense and inflammation and its dysregulation leads to maladaptive responses because of excessive inflammation. There is growing evidence for crosstalk between the central nervous system and the immune system in response to infection. The hypothalamic-pituitary and adrenal axis and the sympathetic nervous system are the two major pathways that mediate this interaction. Epinephrine (Epi) and norepinephrine (NE), respectively are the effectors of these interactions. Upon stimulation, NE is released from sympathetic nerve terminals locally within lymphoid organs and activate adrenoreceptors expressed on immune cells. Similarly, epinephrine secreted from the adrenal gland which is released systemically also exerts influence on immune cells. However, understanding the specific impact of neuroimmunity is still in its infancy. In this review, we focus on the sympathetic nervous system, specifically the role the neurotransmitter norepinephrine has on immune cells. Norepinephrine has been shown to modulate immune cell responses leading to increased anti-inflammatory and blunting of pro-inflammatory effects. Furthermore, there is evidence to suggest that norepinephrine is involved in regulating oxidative metabolism in immune cells. This review attempts to summarize the known effects of norepinephrine on immune cell response and oxidative metabolism in response to infection.

Exploring the Impact of Prior Beta-Blocker and Calcium Channel Blocker Usage on Clinical Outcomes in Critically Ill Patients With Sepsis: An Observational Study

Background Sepsis is associated with increased Ca++ levels in many cell types that can cause cytotoxicity and cell death through multiple mechanisms. In patients with sepsis, limiting beta-adrenergic stimulation may also be beneficial. The intense adrenergic stimulation of sepsis results in cardiac and extra-cardiac effects. In the intensive care unit (ICU), the question of whether to continue calcium channel blockers (CCBs) and beta-blockers in patients with sepsis who were using these medications before ICU admission is of significant concern. Methodology In this prospective observational study, we have included 114 patients who met the inclusion criteria of being diagnosed as having sepsis, aged 18 to 65 years, and expected to stay in the ICU for more than 72 hours. These patients were divided into three groups: group 1 consisted of patients taking CCBs before admission, group 2 included those taking beta-blockers before admission, and group 3 served as the control group, comprising patients who had not taken either of these medications before admission. Disease severity in the ICU was assessed and documented by the Sequential Organ Failure Assessment (SOFA) score. Clinical outcomes among three groups were compared regarding the need for vasopressor support, serum procalcitonin (PCT), serum lactate, serum quantitative C-reactive protein (qCRP), SOFA score, and 28 days mortality. Parametric data were expressed as mean ± standard deviation. The Kruskal-Wallis test was used to analyze parametric data between the two groups and among three groups. Results Mortality was found lower in group 1 (21.05%) and group 2 (26.31%) than in group 3 (47.36%), and this association was found to be statistically significant (P = 0.033). We also found a significant difference in mortality between groups 1 and 3 (P = 0.015) and no significant difference between groups 2 and 3 (P = 0.057). Mortality was found to be significantly associated with high SOFA scores on days 1, 3, and 7. Conclusions From the aforementioned results, we concluded that the mortality rate in patients with sepsis was improved when they were pretreated with beta-blockers or CCBs before admission to the ICU and that medication should be continued if not contraindicated in the ICU course.

Sympathetic System in Wound Healing: Multistage Control in Normal and Diabetic Skin

In this review, we discuss sympathetic regulation in normal and diabetic wound healing. Experimental denervation studies have confirmed that sympathetic nerve endings in skin have an important and complex role in wound healing. Vasoconstrictor neurons secrete norepinephrine (NE) and neuropeptide Y (NPY). Both mediators decrease blood flow and interact with inflammatory cells and keratinocytes. NE acts in an ambiguous way depending on receptor type. Beta2-adrenoceptors could be activated near sympathetic endings; they suppress inflammation and re-epithelialization. Alpha1- and alpha2-adrenoceptors induce inflammation and activate keratinocytes. Sudomotor neurons secrete acetylcholine (ACh) and vasoactive intestinal peptide (VIP). Both induce vasodilatation, angiogenesis, inflammation, keratinocytes proliferation and migration. In healthy skin, all effects are important for successful healing. In treatment of diabetic ulcers, mediator balance could be shifted in different ways. Beta2-adrenoceptors blockade and nicotinic ACh receptors activation are the most promising directions in treatment of diabetic ulcers with neuropathy, but they require further research.

Cardiac Metabolism in Sepsis

The mechanism of sepsis-induced cardiac dysfunction is believed to be different from that of myocardial ischemia. In sepsis, chemical mediators, such as endotoxins, cytokines, and nitric oxide, cause metabolic abnormalities, mitochondrial dysfunction, and downregulation of β-adrenergic receptors. These factors inhibit the production of ATP, essential for myocardial energy metabolism, resulting in cardiac dysfunction. This review focuses on the metabolic changes in sepsis, particularly in the heart. In addition to managing inflammation, interventions focusing on metabolism may be a new therapeutic strategy for cardiac dysfunction due to sepsis.

Beta-Adrenergic Blockade in Critical Illness

Catecholamine upregulation is a core pathophysiological feature in critical illness. Sustained catecholamine β-adrenergic induction produces adverse effects relevant to critical illness management. β-blockers (βB) have proposed roles in various critically ill disease states, including sepsis, trauma, burns, and cardiac arrest. Mounting evidence suggests βB improve hemodynamic and metabolic parameters culminating in decreased burn healing time, reduced mortality in traumatic brain injury, and improved neurologic outcomes following cardiac arrest. In sepsis, βB appear hemodynamically benign after acute resuscitation and may augment cardiac function. The emergence of ultra-rapid βB provides new territory for βB, and early data suggest significant improvements in mitigating atrial fibrillation in persistently tachycardic septic patients. This review summarizes the evidence regarding the pharmacotherapeutic role of βB on relevant pathophysiology and clinical outcomes in various types of critical illness.

Association Between Premorbid Beta-Blocker Exposure and Sepsis Outcomes-The Beta-Blockers in European and Australian/American Septic Patients (BEAST) Study

OBJECTIVES

To examine the effect of premorbid β-blocker exposure on mortality and organ dysfunction in sepsis.

DESIGN

Retrospective observational study.

SETTING

ICUs in Australia, the Czech Republic, and the United States.

PATIENTS

Total of 4,086 critical care patients above 18 years old with sepsis between January 2014 and December 2018.

INTERVENTION

Premorbid beta-blocker exposure.

MEASUREMENTS AND MAIN RESULTS

One thousand five hundred fifty-six patients (38%) with premorbid β-blocker exposure were identified. Overall ICU mortality rate was 15.1%. In adjusted models, premorbid β-blocker exposure was associated with decreased ICU (adjusted odds ratio, 0.80; 95% CI, 0.66-0.97; p = 0.025) and hospital (adjusted odds ratio, 0.83; 95% CI, 0.71-0.99; p = 0.033) mortality. The risk reduction in ICU mortality of 16% was significant (hazard ratio, 0.84, 95% CI, 0.71-0.99; p = 0.037). In particular, exposure to noncardioselective β-blocker before septic episode was associated with decreased mortality. Sequential Organ Failure Assessment score analysis showed that premorbid β-blocker exposure had potential benefits in reducing respiratory and neurologic dysfunction.

CONCLUSIONS

This study suggests that β-blocker exposure prior to sepsis, especially to noncardioselective β blockers, may be associated with better outcome. The findings suggest prospective evaluation of β-blocker use in the management of sepsis.

Successful management of persistent tachycardia using esmolol in 2 dogs with septic shock

OBJECTIVE

To describe the successful management of 2 dogs with septic shock and persistent tachycardia using norepinephrine and esmolol, a short-acting beta receptor antagonist.

SERIES SUMMARY

Two cases are reviewed. In the first case, septic shock with ventricular tachycardia was diagnosed in a 4-year-old neutered female Great Dane that underwent jejunoileal resection and anastomosis for a partial mesenteric torsion. The patient's tachyarrhythmias failed to respond to lidocaine, and an esmolol infusion was used for heart rate control. The condition of the dog improved and she was discharged after 4 days of hospitalization. The second case was a 7-year-old neutered female Cavalier King Charles Spaniel with septic peritonitis. Following surgery for intestinal resection and anastomosis, supraventricular tachycardia developed that was not responsive to volume resuscitation and was treated with an esmolol infusion. The condition of the dog improved and she was discharged after 6 days of hospitalization. Both patients were doing well at the time of long-term follow-up.

NEW OR UNIQUE INFORMATION PROVIDED

This case series highlights a novel method of managing dogs in septic shock with persistent tachycardia based on recently published data in the human literature. The use of esmolol may be considered in certain veterinary patients with septic shock to improve persistent tachycardia not related to hypovolemia.

Metabolic effects of beta-blockers in critically ill patients: A retrospective cohort study

BACKGROUND

Beta-blockers have potential protective features during critical illness. Heart rate reduction, with limited effect on blood pressure and beneficial effects on metabolism, organ function and inflammation have been reported. We examined metabolic effects of beta-blockers among ICU patients, to address the effect on the estimated energy expenditure, measured by carbon dioxide production (VCO₂). Furthermore, we investigated effects on organ function and inflammation.

METHODS

A retrospective study in adult patients admitted to our 17-beds mixed medical-surgical ICU from January 2013 to March 2016. Mechanically ventilated patients who commenced beta-blockers were eligible for inclusion. Exclusion criteria were: beta-blocker therapy in the 7 previous days, treatment duration <48 h, therapeutic hypothermia, and no VCO₂ measurements. Outcome parameters were obtained at 6 different time points from 24 h before until 48 h after beta-blocker commencement. Linear mixed models were used to evaluate trends.

RESULTS

In total 58 patients were included. Various types of beta-blockers were administered, with a median equivalent daily dose to metoprolol of 50.0 mg (IQR 25.0-62.5). The mean heart rate decreased from 103 ± 20 to 91 ± 19 beats per minute after 48 h (p < 0.001), with unaltered blood pressures. Metabolic and other parameters did not show significant differences over time, or parameter changes were due to trends that had already started before beta-blocker commencement.

CONCLUSIONS

No changes in VCO₂ after beta-blocker commencement were demonstrated suggesting no alterations in energy expenditure. Heart rates significantly decreased with unaltered blood pressures. Other parameters did not show trends that could be attributed to beta-blockers effects.

Esmolol infusion in patients with septic shock and tachycardia: a prospective, single-arm, feasibility study

Background

High adrenergic tone appears to be associated with mortality in septic shock, while adrenergic antagonism may improve survival. In preparation for a randomized trial, we conducted a prospective, single-arm pilot study of esmolol infusion for patients with septic shock and tachycardia that persists after adequate volume expansion.

Methods

From April 2016 to March 2017, we enrolled patients admitted to an intensive care unit with sepsis who were receiving vasopressor infusion and were tachycardic despite adequate volume expansion. All patients received a continuous intravenous infusion of esmolol, targeted to heart rate 80–90/min, while receiving vasopressors. The feasibility outcomes were proportion of eligible patients consented, compliance with pre-infusion safety check, and compliance with the titration protocol. The primary clinical outcome was organ-failure-free days (OFFD) at 28 days.

Results

We enrolled 7 of 10 eligible patients. Mean age was 46 (± 19) years, and mean admission APACHE II was 28 (± 8). Median norepinephrine infusion rate at the initiation of esmolol infusion was 0.20 (0.14–0.23) μg/kg/min. Compliance with the safety check was 100%; compliance with components of the titration protocol was 98–100%. OFFD were 26 (24.5–26); all patients survived to day 90. Median peak esmolol infusion was 50 (25–50) μg/kg/min. Median peak norepinephrine infusion rate during esmolol infusion was 0.46 (0.13–0.50) μg/kg/min. Four patients achieved target heart rate. Protocol-defined stop events, suggesting possible intolerance to a given infusion rate, occurred in three patients, all of whom were receiving at least 50 μg/kg/min of esmolol.

Conclusions

In a pilot, single-arm study, we report the first published experience with esmolol infusion in tachycardic patients with septic shock in the United States. These findings support a phase 2 trial of esmolol infusion for septic shock. Lower infusion rates of esmolol infusion may be better tolerated and more feasible than higher infusion rates for such a trial.

Trial registration

This study was retrospectively registered at ClinicalTrials.gov (NCT02841241) on 19 July 2016.

Electronic supplementary material

The online version of this article (10.1186/s40814-018-0321-5) contains supplementary material, which is available to authorized users.

Association between β-blocker use and mortality in critically ill patients: a nested cohort study

BACKGROUND

β-blockers have several indications in critically ill patients and are commonly used. The aim of this study is to examine the relationship between the use of β-blockers in critically ill patients and mortality.

METHODS

This was a nested cohort study in which all medical-surgical ICU patients (N = 523) enrolled in a randomized clinical trial of intensive insulin therapy (ISRCTN07413772) were grouped according to β-blocker use during ICU stay. To account for the indication of β-blockers, we constructed a propensity score using selected clinically-relevant and statistically-significant variables related to β-blocker exposure and outcome. The primary endpoints were all-cause ICU and hospital mortality. Secondary endpoints were the development of severe sepsis during ICU stay, ICU and hospital length of stay, and mechanical ventilation duration. Using multivariable models, we adjusted the associations of β-blockers and these outcomes to the propensity score.

RESULTS

Of the 523 patients enrolled in the study, 89 (17.0%) received β-blockers during their ICU stay. There were no significant associations between β-blocker therapy and ICU mortality (adjusted odds ratio [aOR] 1.56, 95% confidence interval [CI] 0.83-2.9, P = 0.16), hospital mortality (aOR 1.09, 95% CI 0.99-1.20, P = 0.73), the risk of ICU-acquired severe sepsis (aOR 1.67, 95% CI 0.95-2.97, P = 0.08), mechanical ventilation duration (P = 0.17), or ICU length of stay (P = 0.22). However, β-blocker use was associated with increased ICU and hospital mortality among nondiabetic patients (aOR 2.93, 95% CI 1.19-7.23, and 2.43, 95% CI 1.05-5.64, respectively).

CONCLUSIONS

Our study showed that β-blockers during the ICU stay had no significant association with mortality or morbidity. However, β-blocker therapy was associated with increased mortality in non-diabetic patients.

TRIAL REGISTRATION

ISRCTN07413772 ; (dated 13.07.2005).

β-Blockade use for Traumatic Injuries and Immunomodulation: A Review of Proposed Mechanisms and Clinical Evidence

Sympathetic nervous system activation and catecholamine release are important events following injury and infection. The nature and timing of different pathophysiologic insults have significant effects on adrenergic pathways, inflammatory mediators, and the host response. Beta adrenergic receptor blockers (β-blockers) are commonly used for treatment of cardiovascular disease, and recent data suggests that the metabolic and immunomodulatory effects of β-blockers can expand their use. β-blocker therapy can reduce sympathetic activation and hypermetabolism as well as modify glucose homeostasis and cytokine expression. It is the purpose of this review to examine either the biologic basis for proposed mechanisms or to describe current available clinical evidence for the use of β-blockers in traumatic brain injury, spinal cord injury, hemorrhagic shock, acute traumatic coagulopathy, erythropoietic dysfunction, metabolic dysfunction, pulmonary dysfunction, burns, immunomodulation, and sepsis.

Sepsis-induced cardiac dysfunction and β-adrenergic blockade therapy for sepsis

Despite recent advances in medical care, mortality due to sepsis, defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, remains high. Fluid resuscitation and vasopressors are the first-line treatment for sepsis in order to optimize hemodynamic instability caused by vasodilation and increased vascular permeability. However, these therapies, aimed at maintaining blood pressure and blood flow to vital organs, could have deleterious cardiac effects, as cardiomyocyte damage occurs in the early stages of sepsis. Recent experimental and clinical studies have demonstrated that a number of factors contribute to sepsis-induced cardiac dysfunction and the degree of cardiac dysfunction is one of the major prognostic factors of sepsis. Therefore, strategies to prevent further cardiomyocyte damage could be of crucial importance in improving the outcome of sepsis. Among many factors causing sepsis-induced cardiac dysfunction, sympathetic nerve overstimulation, due to endogenous elevated catecholamine levels and exogenous catecholamine administration, is thought to play a major role. β-adrenergic blockade therapy is widely used for ischemic heart disease and chronic heart failure and in the prevention of cardiovascular events in high-risk perioperative patients undergoing major surgery. It has also been shown to restore cardiac function in experimental septic animal models. In a single-center randomized controlled trial, esmolol infusion in patients with septic shock with persistent tachycardia reduced the 28-day mortality. Furthermore, it is likely that β-adrenergic blockade therapy may result in further beneficial effects in patients with sepsis, such as the reduction of inflammatory cytokine production, suppression of hypermetabolic status, maintenance of glucose homeostasis, and improvement of coagulation disorders. Recent accumulating evidence suggests that β-adrenergic blockade could be an attractive therapy to improve the prognosis of sepsis. We await a large multicenter randomized clinical trial to confirm the beneficial effects of β-adrenergic blockade therapy in sepsis, of which mortality is still high.

Targeting cytokines as a treatment for patients with sepsis: A lost cause or a strategy still worthy of pursuit?

Despite often knowing the aetiology of sepsis and its clinical course there has not been the anticipated advances in treatment strategies. Cytokines are influential mediators of immune/inflammatory reactions and in patients with sepsis high circulating levels are implicated in the onset and perpetuation of organ failure. Antagonising the activities of pro-inflammatory cytokines enhances survival in animal models of sepsis but, so far, such a therapeutic strategy has not improved patient outcome. This article addresses the questions of why encouraging laboratory findings have failed to be translated into successful treatments of critically ill patients and whether modifying cytokine activity still remains a promising avenue for therapeutic advance in severe sepsis. In pursuing this task we have selected reports that we believe provide an incisive, critical and balanced view of the topic.

Systematic review of use of β-blockers in sepsis

Background and Aims:

We proposed a review of present literature and systematic analysis of present literature to summarize the evidence on the use of β-blockers on the outcome of a patient with severe sepsis and septic shock.

Material and Methods:

Medline, EMBASE, Cochrane Library were searched from 1946 to December 2013. The bibliography of all relevant articles was hand searched. Full-text search of the grey literature was done through the medical institution database. The database search identified a total of 1241 possible studies. The citation list was hand searched by both the authors. A total of 9 studies were identified.

Results:

Most studies found a benefit from β-blocker administration in sepsis. This included improved heart rate (HR) control, decreased mortality and improvement in acid-base parameters. Chronic β-blocker usage in sepsis was also associated with improved mortality. The administration of β-blockers during sepsis was associated with better control of HR. The methodological quality of all the included studies, however, was poor.

Conclusion:

There is insufficient evidence to justify the routine use of β-blockers in sepsis. A large adequately powered multi-centered randomized controlled clinical trial is required to address the question on the efficacy of β-blocker usage in sepsis. This trial should also consider a number of important questions including the choice of β-blocker used, optimal dosing, timing of intervention, duration of intervention and discontinuation of the drug. Until such time based on the available evidence, there is no place for the use of β-blockers in sepsis in current clinical practice.

When sepsis affects the heart: A case report and literature review

A 59-year-old nursing home patient with Down syndrome was brought to the internal medicine department of our hospital due to fever, cough without expectorate, and dyspnea. A thoracic computed tomography revealed the presence of bilateral basal parenchymal opacities. Her condition deteriorated after admission and troponin reached a peak serum concentration of 16.9 ng/mL. The patient was in cardiogenic shock. In addition to fluid resuscitation, vaso-active amine infusion was administered to achieve hemodynamic stabilization. The differential diagnosis investigated possible pulmonary embolism, myocardial infarction, and myocarditis. Furthermore, a second transthoracic echocardiogram suggested Tako-Tsubo syndrome. This is a septic patient. The purpose of this manuscript is to review studies which formerly examined the possible association between high levels of troponin and mortality to see if it can be considered a positive predictive factor of fatal prognosis as the case of thrombocytopenia, already a positive independent predictive factor of multiple organ failure syndrome, and generally to characterize risk profile in a septic patient.

Do β-Blockers Decrease the Hypermetabolic State in Critically Ill Children With Severe Burns?

BACKGROUND AND OBJECTIVES

Severe burns result in a hypermetabolic state that is associated with increased morbidity and mortality. We reviewed the literature to determine if there is strong evidence that short-term β-blockers reduce the hypermetabolic state or mortality and length of stay (LOS) compared with no therapy in patients with severe burns.

METHODS

A literature search of PubMed, Embase, the Cochrane Database of Systematic Reviews, and BestBETs was conducted on the use of adrenergic β-antagonists in burn patients.

RESULTS

Six randomized controlled trials met the inclusion criteria. Five pediatric trials found that β-blockers reduced the hypermetabolic state (as defined by reduction of cardiac work, rate pressure product, resting energy expenditure, central deposition of fat, and bone mineral loss) and were associated with an improvement in lean muscle mass in patients with severe burns. However, there was no change in LOS or mortality in these children. One adult study in burn patients found shorter LOS in patients treated with β-blockers but no difference in mortality rate. β-blockers were relatively well tolerated, with no differences in adverse effects reported.

CONCLUSIONS

β-blockers seem to reduce the hypermetabolic state in pediatric patients with burns, but there is insufficient evidence to suggest they have an impact on mortality rates or LOS.

Gut and sublingual microvascular effect of esmolol during septic shock in a porcine model

INTRODUCTION

Esmolol may efficiently reduce heart rate (HR) and decrease mortality during septic shock. An improvement of microcirculation dissociated from its macrocirculatory effect may a role. The present study investigated the effect of esmolol on gut and sublingual microcirculation in a resuscitated piglet model of septic shock.

METHODS

Fourteen piglets, anesthetized and mechanically ventilated, received a suspension of live Pseudomonas aeruginosa. They were randomly assigned to two groups: the esmolol (E) group received an infusion of esmolol, started at 7.5 μg⋅kg(-1)⋅min(-1), and progressively increased to achieve a HR below 90 beats⋅min(-1). The control (C) group received an infusion of Ringer's lactate solution. HR, mean arterial pressure (MAP), cardiac index (CI), stroke index (SI), systemic vascular resistance (SVR), arterio-venous blood gas and lactate were recorded. Oxygen consumption (VO2), delivery (DO2) and peripheral extraction (O2ER) were computed. Following an ileostomy, a laser Doppler probe was applied on ileal mucosa to monitor gut microcirculatory laser Doppler flow (GMLDF). Videomicroscopy was also used on ileal mucosa and sublingual areas to evaluate mean flow index (MFI), heterogeneity, ratio of perfused villi and proportion of perfused vessels. Resuscitation maneuvers were performed following a defined algorithm.

RESULTS

Bacterial infusion induced a significant alteration of the gut microcirculation with an increase in HR. Esmolol produced a significant time/group effect with a decrease in HR (P <0.004) and an increase in SVR (P <0.004). Time/group effect was not significant for CI and MAP, but there was a clear trend toward a decrease in CI and MAP in the E group. Time/group effect was not significant for SI, O2ER, DO2, VO2, GMLDF and lactate. A significant time/group effect of ileal microcirculation was found with a lower ileal villi perfusion (P <0.025) in the C group, and a trend toward a better MFI in the E group. No difference between both groups was found regarding microcirculatory parameters in the sublingual area.

CONCLUSIONS

Esmolol provided a maintenance of microcirculation during sepsis despite its negative effects on macrocirculation. Some parameters even showed a trend toward an improvement of the microcirculation in the gut area in the esmolol group.

β-blockers in critically ill patients: from physiology to clinical evidence

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Beta-blockers in septic shock: a review

In septic shock, high adrenergic stress is associated with cardiovascular and systemic adverse effects, which can negatively affect the results. Beta-adrenergic receptor block has been shown to be effective in controlling the disproportionate increase in heart rate, maintaining a favorable hemodynamic profile and apparently improving the efficiency of the cardiovascular system in order to maintain tissue perfusion. They have also been shown to modulate favorably catecholamine-induced immunosuppression and to decrease insulin resistance, protein catabolism, and proinflammatory cytokine expression associated with cardiovascular dysfunction. Selective beta-1 blockers appear to provide better results than non-selective blockers, even suggesting a positive impact on mortality. Future clinical trials are still needed to confirm these findings and define the scope of their benefits.

Perioperative beta-blockade: might the baby go out with the bath water?

Perioperative β-blocker therapy has been advocated to reduce cardiac mortality and morbidity in high-risk cardiac patients undergoing non-cardiac surgery. Core data that supported this intervention and informed international societal guidelines has recently been withdrawn. A subsequent meta-analysis of the remaining data reporting excess mortality has re-opened the debate about the utility of β-blocker therapy in the perioperative period. Criticism of remaining trial designs and new insights into the protective mechanisms of β-blocker therapy in critical illness raise important questions that should now be addressed by a further robust, high-quality randomised control trial.

Early propranolol treatment induces lung heme-oxygenase-1, attenuates metabolic dysfunction, and improves survival following experimental sepsis

Introduction

Pharmacological agents that block beta-adrenergic receptors have been associated with improved outcome in burn injury. It has been hypothesized that injuries leading to a hypermetabolic state, such as septic shock, may also benefit from beta-blockade; however, outcome data in experimental models have been contradictory. Thus, we investigated the effect of beta-blockade with propranolol on survival, hemodynamics, lung heat shock protein (HSP) expression, metabolism and inflammatory markers in a rat cecal ligation and puncture (CLP) model of sepsis.

Methods

Sprague-Dawley rats receiving either repeated doses (30 minutes pre-CLP and every 8 hours for 24 hours postoperatively) of propranolol or control (normal saline), underwent CLP and were monitored for survival. Additionally, lung and blood samples were collected at 6 and 24 hours for analysis. Animals also underwent monitoring to evaluate global hemodynamics.

Results

Seven days following CLP, propranolol improved survival versus control (P < 0.01). Heart rates in the propranolol-treated rats were approximately 23% lower than control rats (P < 0.05) over the first 24 hours, but the mean arterial blood pressure was not different between groups. Metabolic analysis of lung tissue demonstrated an increase in lung ATP/ADP ratio and NAD+ content and a decreased ratio of polyunsaturated fatty acids to monounsaturated fatty acids (PUFA/MUFA). Cytokine analysis of the inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) demonstrated decreased expression of TNF-alpha in both lung and plasma at 24 hours post CLP induced sepsis. Finally, propranolol led to a significant increase in lung hemeoxygenase-1 expression, a key cellular protective heat shock protein (HSP) in the lung. Other lung HSP expression was unchanged.

Conclusions

These results suggest that propranolol treatment may decrease mortality during sepsis potentially via a combination of improving metabolism, suppressing aspects of the inflammatory response and enhancing tissue protection.

Outcome predictors of uncomplicated sepsis

Background

The development of sepsis risk prediction models and treatment guidelines has largely been based on patients presenting in the emergency department (ED) with severe sepsis or septic shock. Therefore, in this study we investigated which patient characteristics might identify patients with an adverse outcome in a heterogeneous group of patients presenting with uncomplicated sepsis to the emergency department (ED).

Findings

We performed a retrospective cohort analysis of all ED patients presenting with uncomplicated sepsis in a large teaching hospital during a 3-month period. During this period, 70 patients fulfilled the criteria of uncomplicated sepsis. Eight died in the hospital. Non-survivors were characterized by a higher abbreviated Mortality in Emergency Department Sepsis (MEDS) score (7.2 ± 3.4 vs. 4.8 ± 2.9, p = 0.03) and a lower Hb (6.6 ± 1.2 vs. 7.7 ± 1.4, p = 0.03), and they used beta-blockers more often (75% vs. 19%, p < 0.01).

Conclusions

Non-survivors of uncomplicated sepsis had on average a higher abbreviated MEDS score, a lower hemoglobin (Hb) and more often used β-blockers compared to survivors. Early identification of these factors might contribute to optimization of sepsis treatment for this patient category and thereby prevent disease progression to severe sepsis or septic shock.

Advancing critical care: time to kiss the right frog

The greatest advances in critical care over the past two decades have been achieved through doing less to the patient. We have learnt through salutary experience that our burgeoning Master-of-the-Universe capabilities and the oh-so-obvious stratagems instilled in us from youth were often ineffective or even deleterious. This re-education process, however, is far from complete. We are now rightly agonizing over the need for better characterization of pathophysiology, earlier identification of disease processes and a more directed approach to therapeutic intervention. We need to delineate the point at which intrinsic and protective adaptation ends and true harmful pathology begins, and how our iatrogenic meddling either helps or hinders. We need to improve trial design in the heterogeneous populations we treat, and to move away from syndromic fixations that, while offering convenience, have generally proved counterproductive. Importantly, we need to discover a far more holistic approach to patient care, evolving from the prevailing overmedicalized, number-crunching perspective towards a true multidisciplinary effort that embraces psychological as well as physiological well-being, with appropriate pharmacological minimization or supplementation. Complacency, with an unfair apportion of blame on the patient for not getting better, is the biggest threat to continued improvement.

Endocrine and metabolic changes during sepsis: an update

The authors have reviewed the most recent and relevant literature from which reasonable conclusions may be drawn. This article highlights important endocrine and metabolic changes, and provides possible explanations for observed perturbations. Obviously infectious disease specialists are not charged with the primary responsibility of addressing these issues, which have largely remained the domain of endocrinologists and intensivists. However, infectious disease specialists use a variety of drugs that can contribute to these abnormalities. Therefore, a constant dialogue between specialists would enhance the quality of care and also contribute immensely to favorable outcomes.

Effects of a peripheral cholinesterase inhibitor on cytokine production and autonomic nervous activity in a rat model of sepsis

PURPOSE

Recently, cholinergic anti-inflammatory pathway manipulation has been proposed as a new strategy to control cytokine production in sepsis. We investigated whether hypercytokinemia can be controlled via this pathway in an animal model of sepsis, with concomitant monitoring of autonomic nervous activity involving heart rate variability (HRV) analysis of electrocardiographic R-R intervals.

METHODS

Sixty-eight adult male Sprague-Dawley rats were used (28 for examination of cytokine production and autonomic nervous activity; 40 for survival analysis). Each part of the study involved four animal groups, including two control groups without drug administration. Sepsis was induced by cecal ligation and puncture (CLP). Distigmine bromide, a peripheral, non-selective cholinesterase inhibitor (0.01mg/kg), was administered subcutaneously 90 min after surgery. Continuous electrocardiograms were recorded for 5 min before and after surgery (at intervals of 5h) in CLP and sham-operated animals for HRV analysis. Blood samples were collected 20 h after surgery for serum cytokine and catecholamine assay.

RESULTS

On HRV analysis, distigmine inhibited reduction of total power and high-frequency components in CLP animals (P<0.05). Distigmine significantly inhibited cytokine induction (IL-6 and IL-10) (P<0.01) as well as increase in serum levels of noradrenaline and dopamine (P<0.05). Distigmine did not significantly improve CLP animal survival rate.

CONCLUSIONS

The cholinesterase inhibitor distigmine inhibited induction of inflammatory cytokines and catecholamines as well as HRV suppression in a rat CLP model, suggesting that an agent modulating the cholinergic anti-inflammatory pathway can control excess cytokine production involved in the pathogenesis of severe sepsis/septic shock.

Stress-related cardiomyopathies

Stress-related cardiomyopathies can be observed in the four following situations: Takotsubo cardiomyopathy or apical ballooning syndrome; acute left ventricular dysfunction associated with subarachnoid hemorrhage; acute left ventricular dysfunction associated with pheochromocytoma and exogenous catecholamine administration; acute left ventricular dysfunction in the critically ill. Cardiac toxicity was mediated more by catecholamines released directly into the heart via neural connection than by those reaching the heart via the bloodstream. The mechanisms underlying the association between this generalized autonomic storm secondary to a life-threatening stress and myocardial toxicity are widely discussed. Takotsubo cardiomyopathy has been reported all over the world and has been acknowledged by the American Heart Association as a form of reversible cardiomyopathy. Four "Mayo Clinic" diagnostic criteria are required for the diagnosis of Takotsubo cardiomyopathy: 1) transient left ventricular wall motion abnormalities involving the apical and/or midventricular myocardial segments with wall motion abnormalities extending beyond a single epicardial coronary artery distribution; 2) absence of obstructive epicardial coronary artery disease that could be responsible for the observed wall motion abnormality; 3) ECG abnormalities, such as transient ST-segment elevation and/or diffuse T wave inversion associated with a slight troponin elevation; and 4) the lack of proven pheochromocytoma and myocarditis. ECG changes and LV dysfunction occur frequently following subarachnoid hemorrhage and ischemic stroke. This entity, referred as neurocardiogenic stunning, was called neurogenic stress-related cardiomyopathy. Stress-related cardiomyopathy has been reported in patients with pheochromocytoma and in patients receiving intravenous exogenous catecholamine administration. The role of a huge increase in endogenous and/or exogenous catecholamine level in critically ill patients (severe sepsis, post cardiac resuscitation, post tachycardia) to explain the onset of myocardial dysfunction was discussed. Further research is needed to understand this complex interaction between heart and brain and to identify risk factors and therapeutic and preventive strategies.

Lipopolysaccharide and sepsis-associated myocardial dysfunction

PURPOSE OF REVIEW

Myocardial dysfunction in sepsis demonstrates acute reduction in left-ventricular function that is potentially reversible yet also associated with increased mortality. The purpose of this review is to discuss the most recent advances in the current knowledge regarding the pathophysiological mechanisms of septic cardiomyopathy.

RECENT FINDINGS

There are numerous candidate pathophysiologic mechanisms for the induction of myocardial dysfunction in sepsis. Sarcolemmal and myofibrillar damage to septic rat cardiomyocytes has been observed, and is likely related to oxidative stress. In a septic chimeric murine model, wild-type mice had decreased cardiac function and increased myocardial TNF-α and IL-6 levels whereas TLR-4 knockout mice had attenuated responses to lipopolysaccharide challenge; thus contributing to the increasing evidence for TLR-4's role in the myocardial inflammatory response to lipopolysaccharide. A similar finding regarding endothelial cell NF-κβ signaling inhibition was found using knockout mice.

SUMMARY

Septic cardiomyopathy is a significant morbid component of severe sepsis and septic shock. Further research into reducing cardiomyocyte damage via oxidative stress, reducing pro-inflammatory responses induced by TLR-4/NF-κβ signaling, decreasing mitochondrial dysfunction, and improving cellular respiration thereby decreasing apoptosis are examples of areas that may be future therapeutic targets.

Preadmission beta-blocker use and 30-day mortality among patients in intensive care: a cohort study

Introduction

Beta-blockers have cardioprotective, metabolic and immunomodulating effects that may be beneficial to patients in intensive care. We examined the association between preadmission beta-blocker use and 30-day mortality following intensive care.

Methods

We identified 8,087 patients over age 45 admitted to one of three multidisciplinary intensive care units (ICUs) between 1999 and 2005. Data on the use of beta-blockers and medications, diagnosis, comorbidities, surgery, markers of socioeconomic status, laboratory tests upon ICU admission, and complete follow-up for mortality were obtained from medical databases. We computed probability of death within 30 days following ICU admission for beta-blocker users and non-users, and the odds ratio (OR) of death as a measure of relative risk using conditional logistic regression and also did a propensity score-matched analysis.

Results

Inclusion of all 8,087 ICU patients in a logistic regression analysis yielded an adjusted OR of 0.82 (95% confidence interval (CI): 0.71 to 0.94) for beta-blocker users compared with non-users. In the propensity score-matched analysis we matched all 1,556 beta-blocker users (19.2% of the entire cohort) with 1,556 non-users; the 30-day mortality was 25.7% among beta-blocker users and 31.4% among non-users (OR 0.74 (95% CI: 0.63 to 0.87)]. The OR was 0.69 (95% CI: 0.54 to 0.88) for surgical ICU patients and 0.71 (95% CI: 0.51 to 0.98) for medical ICU patients. The OR was 0.99 (95% CI: 0.67 to 1.47) among users of non-selective beta-blockers, and 0.70 (95% CI: 0.58 to 0.83) among users of cardioselective beta-blockers.

Conclusions

Preadmission beta-blocker use is associated with reduced mortality following ICU admission.

Propranolol decreases cardiac work in a dose-dependent manner in severely burned children

BACKGROUND

Severe burn is followed by profound cardiac stress. Propranolol, a nonselective β(1,) β(2)-receptor antagonist, decreases cardiac stress, but little is known about the dose necessary to cause optimal effect. Thus, the aim of this study was to determine in a large, prospective, randomized, controlled trial the dose of propranolol that would decrease heart rate ≥15% of admission heart rate and improve cardiac function. Four-hundred six patients with burns >30% total body surface area were enrolled and randomized to receive standard care (controls; n = 235) or standard care plus propranolol (n = 171).

METHODS

Dose-response and drug kinetics of propranolol were performed. Heart rate and mean arterial pressure (MAP) were measured continuously. Cardiac output (CO), cardiac index, stroke volume, rate-pressure product, and cardiac work (CW) were determined at regular intervals. Statistical analysis was performed using analysis of variance with Tukey and Bonferroni corrections and the Student t test when applicable. Significance was accepted at P < .05.

RESULTS

Propranolol given initially at 1 mg/kg per day decreased heart rate by 15% compared with control patients, but was increased to 4 mg/kg per day within the first 10 days to sustain treatment benefits (P < .05). Propranolol decreased CO, rate-pressure product, and CW without deleterious effects on MAP. The effective plasma drug concentrations were achieved in 30 minutes, and the half-life was 4 hours.

CONCLUSION

The data suggest that propranolol is an efficacious modulator of the postburn cardiac response when given at a dose of 4 mg/kg per day, and decreases and sustains heart rate 15% below admission heart rate.

Beta-block the septic heart

OBJECTIVES

Cardiac depression is a well-described manifestation of the sepsis syndrome. An important underlying mechanism is the attenuation of the adrenergic response at the cardiomyocyte level. By reducing their cell-specific function (contractility), the cardiomyocytes reduce their energy expenditure. Consequently, the cardiac myocytes survive in a hibernation-like state as long as intracellular energy generation is limited. The objective of this study was to review β-blocker therapy for the treatment of septic patients.

DATA SOURCE

MEDLINE database.

DATA SYNTHESIS

During established sepsis with organ failure, external adrenergic stimulation of the heart must be kept at a minimum. To blunt the adrenergic response, β-blockers have been used in several preclinical and clinical studies. In septic animals, β-blockers reduced heart rate, whereas stroke volume was maintained. Esmolol in vivo prevented the downregulation of adrenergic pathways, preserving full cardiac function ex vivo. In addition, β-blockers reduced the inflammatory response and the degree of lung injury. Some animal studies documented survival benefits, particularly when β-blockers were administered before the septic insult. In patients with septic shock, blood pressure increased and cardiac indices remained stable with metoprolol administration.

CONCLUSIONS

Preclinical and clinical studies with β-1 receptor blockers during sepsis show promising results. Future studies are needed to establish the optimal dose and timing of its administration.

Evaluation and management of shock States: hypovolemic, distributive, and cardiogenic shock

Shock states have multiple etiologies, but all result in hypoperfusion to vital organs, which can lead to organ failure and death if not quickly and appropriately managed. Pharmacists should be familiar with cardiogenic, distributive, and hypovolemic shock and should be involved in providing safe and effective medical therapies. An accurate diagnosis is necessary to initiate appropriate lifesaving interventions and target therapeutic goals specific to the type of shock. Clinical signs and symptoms, as well as hemodynamic data, help with initial assessment and continued monitoring to provide adequate support for the patient. It is necessary to understand these hemodynamic parameters, medication mechanisms of action, and available mechanical support when developing a patient-specific treatment plan. Rapid therapeutic intervention has been proven to decrease morbidity and mortality and is crucial to providing the best patient outcomes. Pharmacists can provide their expertise in medication selection, titration, monitoring, and dose adjustment in these critically ill patients. This review will focus on parameters used to assess hemodynamic status, the major causes of shock, pathophysiologic factors that cause shock, and therapeutic interventions that should be employed to improve patient outcomes.

Blood glucose control in patients with severe sepsis and septic shock

The main pathophysiological feature of sepsis is the uncontrollable activation of both pro- and anti-inflammatory responses arising from the overwhelming production of mediators such as pro- and anti-inflammatory cytokines. Such an uncontrollable inflammatory response would cause many kinds of metabolic derangements. One such metabolic derangement is hyperglycemia. Accordingly, control of hyperglycemia in sepsis is considered to be a very effective therapeutic approach. However, despite the initial enthusiasm, recent studies reported that tight glycemic control with intensive insulin therapy failed to show a beneficial effect on mortality of patients with severe sepsis and septic shock. One of the main reasons for this disappointing result is the incidence of harmful hypoglycemia during intensive insulin therapy. Therefore, avoidance of hypoglycemia during intensive insulin therapy may be a key issue in effective tight glycemic control. It is generally accepted that glycemic control aimed at a blood glucose level of 80-100 mg/dL, as initially proposed by van den Berghe, seems to be too tight and that such a level of tight glycemic control puts septic patients at increased risk of hypoglycemia. Therefore, now many researchers suggest less strict glycemic control with a target blood glucose level of 140-180 mg/dL. Also specific targeting of glycemic control in diabetic patients should be considered. Since there is a significant correlation between success rate of glycemic control and the degree of hypercytokinemia in septic patients, some countermeasures to hypercytokinemia may be an important aspect of successful glycemic control. Thus, in future, use of an artificial pancreas to avoid hypoglycemia during insulin therapy, special consideration of septic diabetic patients, and control of hypercytokinemia should be considered for more effective glycemic control in patients with severe sepsis and septic shock.

Pharmacological optimization of tissue perfusion

After fluid resuscitation, vasoactive drug treatment represents the major cornerstone for correcting any major impairment of the circulation. However, debate still rages as to the choice of agent, dose, timing, targets, and monitoring modalities that should optimally be used to benefit the patient yet, at the same time, minimize harm. This review highlights these areas and some new pharmacological agents that broaden our therapeutic options.