Early echocardiographic assessment of cardiac function may be prognostically informative in unresuscitated patients with sepsis: A prospective observational study

Purpose

The goal of this study was to explore the association cardiac function at Emergency Department (ED) presentation prior to the initiation of resuscitation, and its change at 3-hours, with adverse outcomes in patients with sepsis.

Methods

This was a prospective observational study of patients presenting to an urban ED with suspected sepsis. Patients had a point-of-care echocardiogram performed prior to initiation of resuscitation and again 3 hours later. Left-ventricular (LV) parameters recorded included e’, and E/e’, and ejection fraction (EF); right-ventricular (RV) function was evaluated using tricuspid annular plane systolic excursion (TAPSE). Logistic and generalized linear regression were used to assess the association of echocardiographic parameters and ≥ 2-point increase in SOFA score at 24 hours (primary outcome) and 24-hours SOFA score and in-hospital mortality (secondary outcomes).

Results

For ΔSOFA ≥ 2 and 24-hour SOFA score, declining LVEF was associated with better outcomes in patients with greater baseline SOFA scores, but worse outcomes in patients with lower baseline scores. A similar relationship was found for ΔTAPSE at 3 hours. Reduced LVEF at presentation was associated with increased mortality after adjusting for ED SOFA score (odds-ratio (OR) 0.76 (CI 0.60–0.96). No relationship between diastolic parameters and outcomes was found. IVF administration was similar across ΔLVEF/TAPSE sub-groups.

Conclusions

Our results suggest that early change in LV and RV systolic function are independently prognostic of sepsis illness severity at 24-hours. Further study is needed to determine if this information can be used to guide treatment and improve outcomes.

Do septic patients with reduced left ventricular ejection fraction require a low-volume resuscitative strategy?

BACKGROUND

Many clinicians are wary of administering 30 cc/kg of intravenous fluid (IVF) to septic patients with reduced left-ventricular ejection fraction (rLVEF), fearing volume overload. Prior studies have used history of heart failure, rather than LVEF measured at presentation, thereby potentially distorting the relationship between rLVEF, IVF, and adverse outcomes. Our goal was to assess the relationship between IVF volume and outcomes in patients with, versus without, rLVEF.

METHODS

This was a prospective observational study performed at an urban Emergency Department (ED). Included patients were adults with suspected sepsis, defined as being treated for infection plus either systolic blood pressure <90 mm/Hg or lactate >2 mmol/L. All patients had LVEF assessed by ED echocardiogram, prior to receipt of >1 l IVF.

MEASUREMENTS AND MAIN RESULTS

We enrolled 73 patients, of whom 33 had rLVEF, defined as <40%. Patients with rLVEF were older, had greater initial lactate, more ICU admission, and more vasopressor use. IVF volume was similar between LVEF groups at 3-h (2.2 (IQR 0.8) vs 2.0 (IQR 2.4) liters) while patients with rLVEF were more likely to achieve 30 cc/kg (61% (CI 44-75) vs 45% (CI 31-60). In the reduced versus not-reduced LVEF groups, hospital days, ICU days, and ventilator days were similar: 8 (IQR 7) vs 6.5 (8.5) days, 7 (IQR 7) vs 5 (4) days, and 4 (IQR 8) vs. 5 (10) days, respectively.

CONCLUSIONS

Septic patients with rLVEF at presentation received similar volume of IVF as those without rLVEF, without an increase in adverse outcomes attributable to volume overload. While validation is needed, our results suggest that limiting IVF administration in the setting of rLVEF is not necessary.

A Novel Low-Cost Ultrasound-Guided Pericardiocentesis Simulation Model: Demonstration of Feasibility

Pericardiocentesis is a rare life-saving procedure for patients with cardiac tamponade. Due to the infrequency of this procedure, simulation models are often used for training. Commercial models are generally expensive. Proposed homemade models offer a lower-cost alternative but can be labor and time intensive. The purpose of this study was to determine the feasibility of a limited use, low-cost ultrasound-guided pericardiocentesis model as a training tool for emergency physicians. Our model proved to be a practical, easily implemented, and acceptable model for training emergency physicians, including residents and students, in ultrasound-guided pericardiocentesis.

Strain Echocardiography in Acute Cardiovascular Diseases

Echocardiography has become a critical tool in the evaluation of patients presenting to the emergency department (ED) with acute cardiovascular diseases and undifferentiated cardiopulmonary symptoms. New technological advances allow clinicians to accurately measure left ventricular (LV) strain, a superior marker of LV systolic function compared to traditional measures such as ejection fraction, but most emergency physicians (EPs) are unfamiliar with this method of echocardiographic assessment. This article discusses the application of LV longitudinal strain in the ED and reviews how it has been used in various disease states including acute heart failure, acute coronary syndromes (ACS) and pulmonary embolism. It is important for EPs to understand the utility of technological and software advances in ultrasound and how new methods can build on traditional two-dimensional and Doppler techniques of standard echocardiography. The next step in competency development for EP-performed focused echocardiography is to adopt novel approaches such as strain using speckle-tracking software in the management of patients with acute cardiovascular disease. With the advent of speckle tracking, strain image acquisition and interpretation has become semi-automated making it something that could be routinely added to the sonographic evaluation of patients presenting to the ED with cardiovascular disease. Once strain imaging is adopted by skilled EPs, focused echocardiography can be expanded and more direct, phenotype-driven care may be achievable for ED patients with a variety of conditions including heart failure, ACS and shock.

Bypassing the Patient: Comparison of Biocompatible Models for the Future of Vascular Tissue Engineering

The objective of vascular tissue engineering is to develop tissue-engineered, biocompatible, small-diameter vessels suitable to withstand in vivo systolic pressures as well as be immunologically compatible with the patient, in order to minimize graft rejection. In this study, we present and compare two models of biocompatible, tissue-engineered vascular grafts (TEVG), using chitosan and acellularized rat aortas as options for scaffolds. Human aortic adventitial smooth muscle cells and fibroblasts were seeded onto a fibrin gel and subsequently wrapped around either of the two scaffolds. After several weeks of maturation in standard culturing conditions, the graft models were analyzed and compared by mechanical testing, cell viability, and histology. Histological and viability data showed that both models were viable and developed similarly, with a scaffold surrounded by two layers of cells, the fibroblasts lying on top of the smooth muscle cells. Both models responded to 200 mM potassium chloride (KCl) (tensions of 38 ± 3, 78 ± 13, and 52 ± 7 μN) and 25 mM 8-bromo-cyclic AMP (tensions of −23 ± 4, −39 ± 10, and −31 ± 12 μN) stimulation by vasoconstriction and vasorelaxation ( n = 3), respectively; however, the chitosan model was unable to maintain the contracted and relaxed tension. Because the acellularized aorta TEVGs were able to maintain stimulated tension better than chitosan TEVGs, we concluded that the acellularized aorta model was better suited for further development.

Cell-based cardiac pumps and tissue-engineered ventricles

Mortalities resulting from cardiovascular disorders remain high, with an urgent need to develop novel treatment modalities. Tissue-engineering therapies aim to provide cell-based alternatives to conventional options. Significant technological advancements have occurred during the last decade towards the fabrication of functional 3D heart muscle in vitro. More recent research has focused on the development of cell-based cardiac pumps and tissue-engineered ventricles. The global objective of this collective work is to simulate the functional performance of the left ventricle, utilizing completely cell-based options. Current prototypes have shown several physiological performance metrics, including the ability of these devices to generate intraluminal pressure upon electrical stimulation. This review will highlight the transition from tissue engineering 3D heart muscle to cell-based cardiac pumps/ventricles.