The International Sepsis Forum's frontiers in sepsis: High cardiac output should be maintained in severe sepsis

Critical Care Echocardiography: Assessing Left and Right Ventricular Function in the Intensive Care Unit

In this review we explore Left Ventricular and Right Ventricular parameters that intensivists can use to evaluate, manage, and monitor the critically ill. Understanding these parameters, their clinical relevance, and potential pitfalls, is crucial for thorough and accurate patient assessment and management. Critical Care Echocardiography encompasses all the advanced cardiac and non-cardiac skillset needed to integrate the findings of Left Ventricular and Right Ventricular size and function. We advocate for a physiologic approach to the critically ill patient, tailoring therapy to reverse the etiology while simultaneously supporting circulation based on a sound understanding of left and right ventricular pressures, volumes, and flow.

Sepsis and Septic Shock Strategies

Three therapeutic principles most substantially improve organ dysfunction and survival in sepsis: early, appropriate antimicrobial therapy; restoration of adequate cellular perfusion; timely source control. The new definitions of sepsis and septic shock reflect the inadequate sensitivity, specify, and lack of prognostication of systemic inflammatory response syndrome criteria. Sequential (sepsis-related) organ failure assessment more effectively prognosticates in sepsis and critical illness. Inadequate cellular perfusion accelerates injury and reestablishing perfusion limits injury. Multiple organ systems are affected by sepsis and septic shock and an evidence-based multipronged approach to systems-based therapy in critical illness results in improve outcomes.

Effects of combined arginine vasopressin and levosimendan on organ function in ovine septic shock

OBJECTIVE

To compare the effects of a first-line therapy of combined arginine vasopressin, levosimendan, and norepinephrine with arginine vasopressin + norepinephrine or norepinephrine alone in ovine septic shock.

DESIGN

Prospective, randomized, controlled laboratory experiment.

SETTING

University animal research facility.

SUBJECTS

Twenty-one chronically instrumented sheep.

INTERVENTIONS

After the onset of fecal peritonitis-induced septic shock (mean arterial pressure <60 mm Hg), sheep were randomly assigned to receive first-line treatment with arginine vasopressin (0.5 mU·kg·min), combined arginine vasopressin (0.5 mU·kg·min) and levosimendan (0.2 μg·kg·min), or normal saline (each n = 7) for 24 hrs. In all groups, open-label norepinephrine was additionally titrated to maintain mean arterial pressure at 70 ± 5 mm Hg, if necessary.

MEASUREMENTS AND MAIN RESULTS

Arginine vasopressin + levosimendan + norepinephrine improved left ventricular contractility (higher stroke work indices at similar or lower preload) and pulmonary function (Pao2/Fio2 ratio) when compared with the other groups (p < .05 each). Both nonadrenergic treatment strategies reduced open-label norepinephrine doses. However, only arginine vasopressin + levosimendan + norepinephrine limited fluid requirements and positive fluid balance vs. both other groups (p < .05 each). In addition, arginine vasopressin + levosimendan + norepinephrine increased mixed venous oxygen saturation as compared with arginine vasopressin + norepinephrine. Histologic tissue analyses and pulmonary hemeoxygenase-1 activity revealed no differences among groups. Notably, arginine vasopressin + levosimendan + norepinephrine therapy reduced pulmonary 3-nitrotyrosine levels (p = .028 vs. control animals) as well as urinary protein/creatinine ratio (p < .05 each) and slightly prolonged survival when compared with both other groups (4 hrs vs. arginine vasopressin + norepinephrine: p = .013; 7 hrs vs. norepinephrine alone: p = .003).

CONCLUSIONS

First-line cardiovascular support with combined arginine vasopressin and levosimendan supplemented with norepinephrine improves myocardial, vascular, pulmonary, and renal function as compared with arginine vasopressin + norepinephrine in septic shock.

Gastric tonometry versus cardiac index as resuscitation goals in septic shock: a multicenter, randomized, controlled trial

INTRODUCTION

Resuscitation goals for septic shock remain controversial. Despite the normalization of systemic hemodynamic variables, tissue hypoperfusion can still persist. Indeed, lactate or oxygen venous saturation may be difficult to interpret. Our hypothesis was that a gastric intramucosal pH-guided resuscitation protocol might improve the outcome of septic shock compared with a standard approach aimed at normalizing systemic parameters such as cardiac index (CI).

METHODS

The 130 septic-shock patients were randomized to two different resuscitation goals: CI >or= 3.0 L/min/m2 (CI group: 66 patients) or intramucosal pH (pHi) >or= 7.32 (pHi group: 64 patients). After correcting basic physiologic parameters, additional resuscitation consisting of more fluids and dobutamine was started if specific goals for each group had not been reached. Several clinical data were registered at baseline and during evolution. Hemodynamic data and pHi values were registered every 6 hours during the protocol. Primary end point was 28 days' mortality.

RESULTS

Both groups were comparable at baseline. The most frequent sources of infection were abdominal sepsis and pneumonia. Twenty-eight day mortality (30.3 vs. 28.1%), peak Therapeutic Intervention Scoring System scores (32.6 +/- 6.5 vs. 33.2 +/- 4.7) and ICU length of stay (12.6 +/- 8.2 vs. 16 +/- 12.4 days) were comparable. A higher proportion of patients exhibited values below the specific target at baseline in the pHi group compared with the CI group (50% vs. 10.9%; P < 0.001). Of 32 patients with a pHi < 7.32 at baseline, only 7 (22%) normalized this parameter after resuscitation. Areas under the receiver operator characteristic curves to predict mortality at baseline, and at 24 and 48 hours were 0.55, 0.61, and 0.47, and 0.70, 0.90, and 0.75, for CI and pHi, respectively.

CONCLUSIONS

Our study failed to demonstrate any survival benefit of using pHi compared with CI as resuscitation goal in septic-shock patients. Nevertheless, a normalization of pHi within 24 hours of resuscitation is a strong signal of therapeutic success, and in contrast, a persistent low pHi despite treatment is associated with a very bad prognosis in septic-shock patients.

Effects of short-term simultaneous infusion of dobutamine and terlipressin in patients with septic shock: the DOBUPRESS study

BACKGROUND

Terlipressin bolus infusion may reduce cardiac output and global oxygen supply. The present study was designed to determine whether dobutamine may counterbalance the terlipressin-induced depression in mixed-venous oxygen saturation (Svo) in patients with catecholamine-dependent septic shock.

METHODS

Prospective, randomized, controlled study performed in a university hospital intensive care unit. Septic shock patients requiring a continuous infusion of norepinephrine (0.9 microg kg(-1) min(-1)) to maintain mean arterial pressure (MAP) at 70 (sd 5) mm Hg were randomly allocated to be treated either with (i) sole norepinephrine infusion (control, n=20), (ii) a single dose of terlipressin 1 mg (n=19), or (iii) a single dose of terlipressin 1 mg followed by dobutamine infusion titrated to reverse the anticipated reduction in Svo2 (n=20). Systemic, pulmonary, and regional haemodynamic variables were obtained at baseline and after 2 and 4 h. Laboratory surrogate markers of organ (dys)function were tested at baseline and after 12 and 24 h.

RESULTS

Terlipressin (with and without dobutamine) infusion preserved MAP at 70 (5) mm Hg, while allowing to reduce norepinephrine requirements to 0.17 (0.2) and 0.2 (0.2) microg kg(-1) min(-1), respectively [vs1.4 (0.3) microg kg(-1) min(-1) in controls at 4 h; each P<0.001]. The terlipressin-linked decrease in Svo2 was reversed by dobutamine at a mean dose of 20 (8) microg kg(-1) min(-1) [Svo2 at 4 h: 59 (11)% vs 69 (12)%, P=0.028].

CONCLUSIONS

In human catecholamine-dependent septic shock, terlipressin (with and without concomitant dobutamine infusion) increases MAP and markedly reduces norepinephrine requirements. Although no adverse events were noticed in the present study, potential benefits of increasing Svo2 after terlipressin bolus infusion need to be weighted against the risk of cardiovascular complications resulting from high-dose dobutamine.

Continuous versus bolus infusion of terlipressin in ovine endotoxemia

In patients with sepsis, hemodynamic support is often complicated by a tachyphylaxis against conventional vasopressor agents. Bolus infusion of terlipressin, a vasopressin analog, has been reported to increase mean arterial pressure in patients with catecholamine-resistant septic shock. However, bolus infusion of terlipressin may be associated with severe side effects, including pulmonary vasoconstriction and impairment of oxygen delivery. We hypothesized that continuous low-dose infusion of terlipressin may reverse sepsis-related systemic arterial hypotension with reduced side effects as compared with the traditional concept of bolus administration. Twenty-seven adult sheep were instrumented for chronic study. After a baseline measurement, Salmonella typhosa endotoxin (10 ng.kg-1.min-1) was continuously administered for the next 40 h. After 16 h of endotoxemia, the surviving sheep (n = 24) were randomly assigned to be treated with either a continuous infusion of terlipressin (2 mg for 24 h), bolus injections of terlipressin (1 mg every 6 h), or placebo (normal saline; each n = 8). Continuous infusion of terlipressin permanently reversed endotoxin-induced systemic arterial hypotension (P < 0.001) and improved left ventricular stroke work index in all sheep (P < 0.05). Intermittent bolus injections of terlipressin were linked to decreases in heart rate and cardiac index and increases in pulmonary vascular resistance index (each, P < 0.001). These unwanted side effects were prevented by continuous low-dose infusion of the drug. In conclusion, continuous infusion of terlipressin stabilized hemodynamics and improved myocardial performance in endotoxemic ewes without obvious side effects. Continuous low-dose terlipressin infusion may represent a useful alternative treatment of arterial hypotension related to sepsis and systemic inflammatory response syndrome.

A cardiovascular drug rescues mice from lethal sepsis by selectively attenuating a late-acting proinflammatory mediator, high mobility group box 1

The pathogenesis of sepsis is mediated in part by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., TNF, IL-1, and IFN-gamma) and late (e.g., high mobility group box 1 (HMGB1) protein) proinflammatory cytokines. The recent discovery of HMGB1 as a late mediator of lethal sepsis has prompted investigation for development of new experimental therapeutics. We found that many steroidal drugs (such as dexamethasone and cortisone) and nonsteroidal anti-inflammatory drugs (such as aspirin, ibuprofen, and indomethacin) failed to influence endotoxin-induced HMGB1 release even at superpharmacological concentrations (up to 10-25 microM). However, several steroid-like pigments (tanshinone I, tanshinone IIA, and cryptotanshinone) of a popular Chinese herb, Danshen (Salvia miltiorrhiza), dose dependently attenuated endotoxin-induced HMGB1 release in macrophage/monocyte cultures. A water-soluble tanshinone IIA sodium sulfonate derivative (TSNIIA-SS), which has been widely used as a Chinese medicine for patients with cardiovascular disorders, selectively abrogated endotoxin-induced HMGB1 cytoplasmic translocation and release in a glucocorticoid receptor-independent manner. Administration of TSNIIA-SS significantly protected mice against lethal endotoxemia and rescued mice from lethal sepsis even when the first dose was given 24 h after the onset of sepsis. The therapeutic effects were partly attributable to attenuation of systemic accumulation of HMGB1 (but not TNF and NO) and improvement of cardiovascular physiologic parameters (e.g., decrease in total peripheral vascular resistance and increase in cardiac stroke volume) in septic animals. Taken together, these data re-enforce the pathogenic role of HMGB1 in lethal sepsis, and support a therapeutic potential for TSNIIA-SS in the treatment of human sepsis.

Dobutamine reverses the vasopressin-associated impairment in cardiac index and systemic oxygen supply in ovine endotoxemia

Introduction

Arginine vasopressin (AVP) is increasingly used to treat sepsis-related vasodilation and to decrease catecholamine requirements. However, AVP infusion may be associated with a marked decrease in systemic blood flow and oxygen transport. The purpose of the present study was to evaluate whether dobutamine may be titrated to reverse the AVP-related decrease in cardiac index (CI) and systemic oxygen delivery index (DO₂I) in an established model of ovine endotoxemia.

Methods

Twenty-four adult ewes were chronically instrumented to determine cardiopulmonary hemodynamics and global oxygen transport. All ewes received a continuous endotoxin infusion that contributed to a hypotensive-hyperdynamic circulation and death of five sheep. After 16 hours of endotoxemia, the surviving ewes (n = 19; weight 35.6 ± 1.5 kg (mean ± SEM)) were randomized to receive either AVP (0.04 Umin^-1) and dobutamine (n = 8) or the vehicle (normal saline; n = 6) and compared with a third group treated with AVP infusion alone (n = 5). Dobutamine infusion was started at an initial rate of 2 μg kg^-1min^-1 and was increased to 5 and 10 μg kg^-1 min^-1 after 30 and 60 minutes, respectively.

Results

AVP infusion increased mean arterial pressure (MAP) and systemic vascular resistance index at the expense of a markedly decreased CI (4.1 ± 0.5 versus 8.2 ± 0.3 l min^-1 m^-2), DO₂I (577 ± 68 versus 1,150 ± 50 ml min^-1 m^-2) and mixed-venous oxygen saturation (S_vO₂; 54.5 ± 1.8% versus 69.4 ± 1.0%; all p < 0.001 versus control). Dobutamine dose-dependently reversed the decrease in CI (8.8 ± 0.7 l min^-1 m^-2 versus 4.4 ± 0.5 l min^-1 m^-2), DO₂I (1323 ± 102 versus 633 ± 61 ml min^-1 m^-2) and S_vO₂ (72.2 ± 1.7% versus 56.5 ± 2.0%, all p < 0.001 at dobutamine 10 μg kg^-1 min^-1 versus AVP group) and further increased MAP.

Conclusion

This study provides evidence that dobutamine is a useful agent for reversing the AVP-associated impairment in systemic blood flow and global oxygen transport.

Infusion of the β-adrenergic blocker esmolol attenuates myocardial dysfunction in septic rats*

OBJECTIVE

Since beta-blocker therapy is known to be effective in patients with an injured heart, such as infarction, we designed the present study to examine the protective effects of infusion of the beta1-selective blocker esmolol on myocardial function in peritonitis-induced septic rats using an isolated working heart preparation.

DESIGN

Randomized animal study.

SETTING

University research laboratory.

SUBJECTS

Thirty-one rats treated with cecal ligation and perforation to evoke peritonitis.

INTERVENTIONS

After cecal ligation and perforation, rats were randomly allocated to the control group (normal saline 2 mL/hr, n = 11), low-dose esmolol group (10 mg/kg/hr, n = 10), or high-dose esmolol group (20 mg/kg/hr, n = 10). After obtaining blood samples for measurement of arterial lactate and tumor necrosis factor-alpha at 24 hrs, we assessed cardiac output, myocardial oxygen consumption, and cardiac efficiency (cardiac output x peak systolic pressure/myocardial oxygen consumption) at various preloads in an isolated perfused heart preparation.

MEASUREMENTS AND MAIN RESULTS

Esmolol infusion did not cause an elevation of arterial lactate levels but reduced tumor necrosis factor-alpha concentrations vs. the control group (p < .05). Both cardiac output and cardiac efficiency in the esmolol-treated rats were significantly higher throughout the study periods vs. the control group (p < .05).

CONCLUSIONS

Esmolol infusion in sepsis improved oxygen utilization of myocardium and preserved myocardial function.

Einsatz von Vasopressin und Terlipressin bei Sepsis und systemischen Entzündungsreaktionen

Vasopressin and terlipressin are increasingly used as alternative non-adrenergic vasopressors for hemodynamic support of septic patients with arterial hypotension. Despite excellent vasopressive effects, vasopressin analogues may potentially impair macro-hemodynamics, oxygen transport and microvascular blood flow. Due to those unwanted side-effects, vasopressin and terlipressin may potentially compromise organ function and possibly foster the development of multiple organ failure. This review article discusses the results of clinical and experimental studies to judge the effects of vasopressin and terlipressin on microcirculation, oxygen supply, metabolism and organ function in patients with sepsis or systemic inflammatory response syndrome (SIRS). Although vasopressin analogues are emerging as promising alternatives to treat catecholamine-refractory hypotension, there is no evidence that vasopressin receptor agonists improve outcome. To date, vasopressin and terlipressin can, therefore, not be recommended for routine clinical use.