Improvement of left ventricular relaxation as assessed by tissue Doppler imaging in fluid-responsive critically ill septic patients

Critical Care Ultrasound in Shock: A Comprehensive Review of Ultrasound Protocol for Hemodynamic Assessment in the Intensive Care Unit

Shock is a life-threatening condition that requires prompt recognition and treatment to prevent organ failure. In the intensive care unit, shock is a common presentation, and its management is challenging. Critical care ultrasound has emerged as a reliable and reproducible tool in diagnosing and classifying shock. This comprehensive review proposes an ultrasound-based protocol for the hemodynamic assessment of shock to guide its management in the ICU. The protocol classifies shock as either low or high cardiac index and differentiates obstructive, hypovolemic, cardiogenic, and distributive etiologies. In distributive shock, the protocol proposes a hemodynamic-based approach that considers the presence of dynamic obstruction, fluid responsiveness, fluid tolerance, and ventriculo-arterial coupling. The protocol gives value to quantitative measures based on critical care ultrasound to guide hemodynamic management. Using critical care ultrasound for a comprehensive hemodynamic assessment can help clinicians diagnose the etiology of shock and define the appropriate treatment while monitoring the response. The protocol's use in the ICU can facilitate prompt recognition, diagnosis, and management of shock, ultimately improving patient outcomes.

Sepsis-Induced myocardial dysfunction: heterogeneity of functional effects and clinical significance

Sepsis is a life-threatening disease state characterized by organ dysfunction and a dysregulated response to infection. The heart is one of the many organs affected by sepsis, in an entity termed sepsis-induced cardiomyopathy. This was initially used to describe a reversible depression in ejection fraction with ventricular dilation but advances in echocardiography and introduction of new techniques such as speckle tracking have led to descriptions of other common abnormalities in cardiac function associated with sepsis. This includes not only depression of systolic function, but also supranormal ejection fraction, diastolic dysfunction, and right ventricular dysfunction. These reports have led to inconsistent definitions of sepsis-induced cardiomyopathy. Just as there is heterogeneity among patients with sepsis, there is heterogeneity in the cardiac response; thus resuscitating these patients with a single approach is likely suboptimal. Many factors affect the heart in sepsis including inflammatory mediators, catecholamine responsiveness, and pathogen related toxins. This review will discuss different functional effects characterized by echocardiographic changes in sepsis and their prognostic and management implications.

Fluid challenge in critically ill patients receiving haemodynamic monitoring: a systematic review and comparison of two decades

Introduction

Fluid challenges are widely adopted in critically ill patients to reverse haemodynamic instability. We reviewed the literature to appraise fluid challenge characteristics in intensive care unit (ICU) patients receiving haemodynamic monitoring and considered two decades: 2000–2010 and 2011–2021.

Methods

We assessed research studies and collected data regarding study setting, patient population, fluid challenge characteristics, and monitoring. MEDLINE, Embase, and Cochrane search engines were used. A fluid challenge was defined as an infusion of a definite quantity of fluid (expressed as a volume in mL or ml/kg) in a fixed time (expressed in minutes), whose outcome was defined as a change in predefined haemodynamic variables above a predetermined threshold.

Results

We included 124 studies, 32 (25.8%) published in 2000–2010 and 92 (74.2%) in 2011–2021, overall enrolling 6,086 patients, who presented sepsis/septic shock in 50.6% of cases. The fluid challenge usually consisted of 500 mL (76.6%) of crystalloids (56.6%) infused with a rate of 25 mL/min. Fluid responsiveness was usually defined by a cardiac output/index (CO/CI) increase ≥ 15% (70.9%). The infusion time was quicker (15 min vs 30 min), and crystalloids were more frequent in the 2011–2021 compared to the 2000–2010 period.

Conclusions

In the literature, fluid challenges are usually performed by infusing 500 mL of crystalloids bolus in less than 20 min. A positive fluid challenge response, reported in 52% of ICU patients, is generally defined by a CO/CI increase ≥ 15%. Compared to the 2000–2010 decade, in 2011–2021 the infusion time of the fluid challenge was shorter, and crystalloids were more frequently used.

Left Ventricular Diastolic Dysfunction in ARDS Patients

Background: The aim of this study was to evaluate the possible presence of diastolic dysfunction and its possible effects in terms of respiratory mechanics, gas exchange and lung recruitability in mechanically ventilated ARDS. Methods: Consecutive patients admitted in intensive care unit (ICU) with ARDS were enrolled. Echocardiographic evaluation was acquired at clinical PEEP level. Lung CT-scan was performed at 5 and 45 cmH₂O. In the study, 2 levels of PEEP (5 and 15 cmH₂O) were randomly applied. Results: A total of 30 patients were enrolled with a mean PaO₂/FiO₂ and a median PEEP of 137 ± 52 and 10 [9–10] cmH₂O, respectively. Of those, 9 patients (30%) had a diastolic dysfunction of grade 1, 2 and 3 in 33%, 45% and 22%, respectively, without any difference in gas exchange and respiratory mechanics. The total lung weight was significantly higher in patients with diastolic dysfunction (1669 [1354–1909] versus 1554 [1146–1942] g) but the lung recruitability was similar between groups (33.3 [27.3–41.4] versus 30.6 [20.0–38.8] %). Left ventricular ejection fraction (57 [39–62] versus 60 [57–60]%) and TAPSE (20.0 [17.0–24.0] versus 24.0 [20.0–27.0] mL) were similar between the two groups. The response to changes of PEEP from 5 to 15 cmH₂O in terms of oxygenation and respiratory mechanics was not affected by the presence of diastolic dysfunction. Conclusions: ARDS patients with left ventricular diastolic dysfunction presented a higher amount of lung edema and worse outcome.

Role of Electromechanical Dyssynchrony Assessment During Acute Circulatory Failure and Its Relation to Ventriculo-Arterial Coupling

Introduction

Two parallel paradigms of cardiovascular efficiency and haemodynamic optimisation coexist in haemodynamic research. Targeting ventriculo-arterial (VA) coupling [i.e., the ratio between arterial and ventricular elastance (E_V)] and electromechanical coupling are two promising approaches in acute circulatory failure. However, validation of the parameters of electromechanical coupling in critically ill patients is ongoing. Furthermore, a unifying link between VA and electromechanical coupling may exist, as E_V is correlated with different times of the cardiac cycle.

Materials and Methods

This study was a retrospective analysis of a prospectively collected observational database from one tertiary center ICU. We analyzed the relationship between electromechanical dyssynchrony and acute circulatory failure hemodynamics before and after treatment (i.e., fluid expansion, dobutamine, or norepinephrine infusion). The relationship between electromechanical coupling and VA coupling was also investigated. Adult patients with haemodynamic instability were included. Haemodynamic parameters, including arterial pressure, cardiac index, VA coupling, stroke work index/pressure–volume area (SWI/PVA), t-IVT, and Tei's index, were collected before and after treatment. A t-IVT of >12 s/min was classified as intraventricular dyssynchrony.

Results

We included 54 patients; 39 (72.2%) were classified as having intraventricular dyssynchrony at baseline. These patients with baseline dyssynchrony showed a statistically significant amelioration of t-IVT (from 18 ± 4 s to 14 ± 6 s, p = 0.001), left ventricular E_V [from 1.1 (0.72–1.52) to 1.33 (0.84–1.67) mmHg mL⁻¹, p = 0.001], VA coupling [from 2 (1.67–2.59) to 1.80 (1.40–2.21), p = 0.001], and SWI/PVA [from 0.58 (0.49–0.65) to 0.64 (0.51–0.68), p = 0.007]. Patients without baseline dyssynchrony showed no statistically significant results. The improvement in VA coupling was mediated by an amelioration of E_V. All patients improved their arterial pressure and cardiac index with treatment. The haemodynamic treatment group exhibited no effect on changing t-IVT.

Conclusion

Acute circulatory failure is associated with electromechanical dyssynchrony. Cardiac electromechanical coupling was improved by haemodynamic treatment only if altered at baseline. The improvement of cardiac electromechanical coupling was associated with the improvement of markers of cardiocirculatory efficacy and efficiency (i.e., SWI/PVA and VA coupling). This study was the first to demonstrate a possible link between cardiac electromechanical coupling and VA coupling in patients with acute circulatory failure.

Can blood loss be assessed by echocardiography? An experimental study on a controlled hemorrhagic shock model in piglets

BACKGROUND

Assessment of the volemic loss is a major challenge during the management of hemorrhagic shock. Echocardiography is an increasingly used noninvasive tool for hemodynamic assessment. In mechanically ventilated patients, some studies suggest that respiratory variations of mean subaortic time-velocity integral (∆VTI) would be predictive of fluid filling response. An experimental model of controlled hemorrhagic shock provides a precise approach to study correlation between blood volume and cardiac ultrasonographic parameters.

OBJECTIVES

The main objective was to analyze the ∆VTI changes during hemorrhage in an anesthetized-piglet model of controlled hemorrhagic shock. The secondary objective was to evaluate ∆VTI during the resuscitation process after hemorrhage and other echocardiographic parameters changes during the whole protocol.

METHODS

Twenty-four anesthetized and ventilated piglets were bled until mean arterial pressure reached 40 mm Hg. Controlled hemorrhage was maintained for 30 minutes before randomizing the piglets to two resuscitation groups: fluid filling group resuscitated with saline solution and noradrenaline group resuscitated with saline solution and noradrenaline. Echocardiography and hemodynamic measures, including pulsed pressure variations (PPV), were performed at different stages of the protocol.

RESULTS

The correlation coefficient between ΔVTI and PPV with the volume of bleeding during the hemorrhagic phase were respectively 0.24 (95% confidence interval, 0.08-0.39; p < 0.01) and 0.57 (95% CI, 0.44-0.67; p < 0.01). Two parameters had a moderate correlation coefficient with hemorrhage volume (over 0.5): mean subaortic time-velocity index (VTI) and mitral annulus diastolic tissular velocity (E').

CONCLUSION

In this hemorrhagic shock model, ΔVTI had a low correlation with the volume of bleeding, but VTI and E' had a correlation with blood volume comparable to that of PPV.

Assessing Fluid Intolerance with Doppler Ultrasonography: A Physiological Framework

Ultrasonography is becoming the favored hemodynamic monitoring utensil of emergentologists, anesthesiologists and intensivists. While the roles of ultrasound grow and evolve, many clinical applications of ultrasound stem from qualitative, image-based protocols, especially for diagnosing and managing circulatory failure. Often, these algorithms imply or suggest treatment. For example, intravenous fluids are opted for or against based upon ultrasonographic signs of preload and estimation of the left ventricular ejection fraction. Though appealing, image-based algorithms skirt some foundational tenets of cardiac physiology; namely, (1) the relationship between cardiac filling and stroke volume varies considerably in the critically ill, (2) the correlation between cardiac filling and total vascular volume is poor and (3) the ejection fraction is not purely an appraisal of cardiac function but rather a measure of coupling between the ventricle and the arterial load. Therefore, management decisions could be enhanced by quantitative approaches, enabled by Doppler ultrasonography. Both fluid ‘responsiveness’ and ‘tolerance’ are evaluated by Doppler ultrasound, but the physiological relationship between these constructs is nebulous. Accordingly, it is argued that the link between them is founded upon the Frank–Starling–Sarnoff relationship and that this framework helps direct future ultrasound protocols, explains seemingly discordant findings and steers new routes of enquiry.

Accuracy of pulse pressure variations for fluid responsiveness prediction in mechanically ventilated patients with biphasic positive airway pressure mode

The accuracy of pulse pressure variation (PPV) to predict fluid responsiveness using pressure-controlled (PC) instead of volume-controlled modes is under debate. To specifically address this issue, we designed a study to evaluate the accuracy of PPV to predict fluid responsiveness in severe septic patients who were mechanically ventilated with biphasic positive airway pressure (BIPAP) PC-ventilation mode. 45 patients with sepsis or septic shock and who were mechanically ventilated with BIPAP mode and a target tidal volume of 7-8 ml/kg were included. PPV was automatically assessed at baseline and after a standard fluid challenge (Ringer's lactate 500 ml). A 15% increase in stroke volume (SV) defined fluid responsiveness. The predictive value of PPV was evaluated through a receiver operating characteristic (ROC) curve analysis and "gray zone" statistical approach. 20 (44%) patients were considered fluid responders. We identified a significant relationship between PPV decrease after volume expansion and SV increase (spearman ρ = - 0.5, p < 0.001). The area under ROC curve for PPV was 0.71 (95%CI 0.56-0.87, p = 0.007). The best cut-off (based on Youden's index) was 8%, with a sensitivity of 80% and specificity of 60%. Using a gray zone approach, we identified that PPV values comprised between 5 and 15% do not allow a reliable fluid responsiveness prediction. In critically ill septic patients ventilated under BIPAP mode, PPV appears to be an accurate method for fluid responsiveness prediction. However, PPV values comprised between 5 and 15% constitute a gray zone that does not allow a reliable fluid responsiveness prediction.

Left ventricular longitudinal strain variations assessed by speckle-tracking echocardiography after a passive leg raising maneuver in patients with acute circulatory failure to predict fluid responsiveness: A prospective, observational study

Background

An association was reported between the left ventricular longitudinal strain (LV-LS) and preload. LV-LS reflects the left cardiac function curve as it is the ratio of shortening over diastolic dimension. The aim of this study was to determine the sensitivity and specificity of LV-LS variations after a passive leg raising (PLR) maneuver to predict fluid responsiveness in intensive care unit (ICU) patients with acute circulatory failure (ACF).

Methods

Patients with ACF were prospectively included. Preload-dependency was defined as a velocity time integral (VTI) variation greater than 10% between baseline (T0) and PLR (T1), distinguishing the preload-dependent (PLD+) group and the preload-independent (PLD-) group. A 7-cycles, 4-chamber echocardiography loop was registered at T0 and T1, and strain analysis was performed off-line by a blind clinician. A general linear model for repeated measures was used to compare the LV-LS variation (T0 to T1) between the two groups.

Results

From June 2018 to August 2019, 60 patients (PLD+ = 33, PLD- = 27) were consecutively enrolled. The VTI variations after PLR were +21% (±8) in the PLD+ group and -1% (±7) in the PLD- group (p<0.01). Mean baseline LV-LS was -11.3% (±4.2) in the PLD+ group and -13.0% (±4.2) in the PLD- group (p = 0.12). LV-LS increased in the whole population after PLR +16.0% (±4.0) (p = 0.04). The LV-LS variations after PLR were +19.0% (±31) (p = 0.05) in the PLD+ group and +11.0% (±38) (p = 0.25) in the PLD- group, with no significant difference between the two groups (p = 0.08). The area under the curve for the LV-LS variations between T0 and T1 was 0.63 [0.48–0.77].

Conclusion

Our study confirms that LV-LS is load-dependent; however, the variations in LV-LS after PLR is not a discriminating criterion to predict fluid responsiveness of ICU patients with ACF in this cohort.

Echocardiographic Assessment of Left Ventricular Systolic and Diastolic Functions in Dogs with Severe Sepsis and Septic Shock; Longitudinal Study

Simple Summary

Sepsis is associated with cardiovascular changes. The aim of the study was to determine sepsis-induced myocardial dysfunction in dogs with severe sepsis and septic shock using transthoracic echocardiography. Clinical, laboratory and cardiologic examinations for the septic dogs were performed at admission, 6 and 24 h, and on the day of discharge from the hospital. Left ventricular (LV) systolic dysfunction, LV diastolic dysfunction, and both types of the dysfunction were present in 13%, 70%, and 9% of dogs with sepsis, respectively. Dogs with LV diastolic dysfunction had a worse outcome and short-term mortality. Transthoracic echocardiography can be used for monitoring cardiovascular dysfunction in dogs with sepsis.

Abstract

The purpose of this study was to monitor left ventricular systolic dysfunction (LVSD) and diastolic dysfunction (LVDD) using transthoracic echocardiography (TTE) in dogs with severe sepsis and septic shock (SS/SS). A prospective longitudinal study using 23 dogs with SS/SS (experimental group) and 20 healthy dogs (control group) were carried out. All the clinical, laboratory and cardiologic examinations for the experimental dogs were performed at admission, 6 and 24 h after the start of treatment and on the day of discharge. LVSD was described as LV ejection fraction (LVEF) < 50%. LVDD was determined when the septal mitral annulus early diastolic velocity (LVEm) was <8 cm/s. LVSD and LVDD were present in 3 and 16 dogs with SS/SS, respectively, with both types of dysfunction present in 2 of the dogs. Although all the dogs with LVSD survived, 8 dogs with LVDD did not. The survival period was significantly shorter in dogs with an LVEm < 8 cm/s (1.3 ± 1.4 days). In conclusion, LVDD, rather than LVSD, was a common cardiovascular abnormality in the septic dogs, and this may be a negative prognostic factor. TTE is a useful tool for the identifying and monitoring of myocardial dysfunction in the dogs with SS/SS.

Assessment of left-ventricular diastolic function in pediatric intensive-care patients: a review of parameters and indications compared with those for adults

BACKGROUND

The incidence of diastolic heart failure has increased over time. The evaluation of left-ventricular diastolic function is complex, ongoing, and remains poorly performed in pediatric intensive-care patients. This study aimed to review the literature and to provide an update on the evaluation of left-ventricular diastolic function in adults and children in intensive care.

DATA SOURCES

We searched data from PubMed/Medline. Thirty-two studies were included. Four pragmatic questions were identified: (1) What is the physiopathology of diastolic dysfunction? (2) Which tools are required to evaluate diastolic function? (3) What are the echocardiographic criteria needed to evaluate diastolic function? (4) When should diastolic function be evaluated in pediatric intensive care?

RESULTS

Early diastole allows characterization of relaxation, whereas compliance assessments and filling pressures are evaluated during late diastole. The evolution of diastolic function differs between adults and children. Unlike in adults, decreased compliance occurs at the same time as delayed relaxation in children. Diastolic function can be evaluated by Doppler echocardiography. The echocardiographic criteria for ventricular relaxation include the E wave, E/A wave ratio, and isovolumic relaxation time. Ventricular compliance can be assessed by the E/e' wave ratio, atrial volume, and Ap wave duration during pulmonary vein flow. In adult intensive-care patients, the E/e' ratio can be used as an index of tolerance for volume expansion in septic patients and to adjust the inotropic support.

CONCLUSION

Clinical studies would allow some of these parameters to be validated for use in children in intensive care.

Machine learning methods to improve bedside fluid responsiveness prediction in severe sepsis or septic shock: an observational study

BACKGROUND

Passive leg raising (PLR) predicts fluid responsiveness in critical illness, although restrictions in mobilising patients often preclude this haemodynamic challenge being used. We investigated whether machine learning applied on transthoracic echocardiography (TTE) data might be used as a tool for predicting fluid responsiveness in critically ill patients.

METHODS

We studied, 100 critically ill patients (mean age: 62 yr [standard deviation: 14]) with severe sepsis or septic shock prospectively over 24 months. Transthoracic echocardiography measurements were performed at baseline, after PLR, and before and after a standardised fluid challenge in learning and test populations (n=50 patients each). A 15% increase in stroke volume defined fluid responsiveness. The machine learning methods used were classification and regression tree (CART), partial least-squares regression (PLS), neural network (NNET), and linear discriminant analysis (LDA). Each method was applied offline to determine whether fluid responsiveness may be predicted from left and right cardiac ventricular physiological changes detected by cardiac ultrasound. Predictive values for fluid responsiveness were compared by receiver operating characteristics (area under the curve [AUC]; mean [95% confidence intervals]).

RESULTS

In the learning sample, the AUC values were PLR 0.76 (0.62-0.89), CART 0.83 (0.73-0.94), PLS 0.97 (0.93-1), NNET 0.93 (0.85-1), and LDA 0.90 (0.81-0.98). In the test sample, the AUC values were PLR 0.77 (0.64-0.91), CART 0.68 (0.54-0.81), PLS 0.83 (0.71-0.96), NNET 0.83 (0.71-0.94), and LDA 0.85 (0.74-0.96) respectively. The PLS model identified inferior vena cava collapsibility, velocity-time integral, S-wave, E/Ea ratio, and E-wave as key echocardiographic parameters.

CONCLUSIONS

Machine learning generated several models for predicting fluid responsiveness that were comparable with the haemodynamic response to PLR.

Diastolic dysfunction of the left ventricle - a practical approach for an anaesthetist

Bedside point-of-care echocardiography is being increasingly incorporated in peri-operative assessment and in intensive care units. Because of availability of tissue Doppler imaging in the modern ultrasound machines there has been an increased interest in research of diastolic function of left ventricle. The diastolic function is crucial for the hemodynamically effective function of the heart. Diastolic dysfunction is a well-established risk factor of the major adverse cardiac events during perioperative period, complications during weaning from ventilator and prognostic factor of mortality in septic shock.

Prognostic importance of tissue Doppler imaging of systolic and diastolic functions in dogs with severe sepsis and septic shock

The goal of this study was to determine the distribution of left ventricular (LV) systolic and diastolic dysfunctions and their prognostic value in canine parvovirus-infected dogs suffering from severe sepsis and septic shock (SS/SS). Twenty dogs with SS/SS (experimental group) and 18 healthy dogs (control group) were used in the study. Systolic and diastolic dysfunction was present in three (15%) and 14 (70%) diseased dogs, respectively, with both types of dysfunction present in two (10%) of the patients. These dogs were split into two groups: survivors (Sv, n = 14) and non-survivors (non-Sv, n = 6). The pulsed wave tissue Doppler (PW-TDI) septal mitral annulus systolic velocity (LVS'), an index of systolic dysfunction, had a high sensitivity and specificity to differentiate Sv and non-Sv animals, with values of 83.3% (95% CI: 41.6-98.4) and 83.3% (95% CI: 59.8-94.8), respectively, at an optimum cut-off point of ≥ 9.90. The PW-TDI septal early mitral annulus early-diastolic peak velocity (E'), an index of diastolic dysfunction, had the best sensitivity and specificity to differentiate Sv and non-Sv dogs, with values of 100% (95% CI: 55.2-100) and 100% (95% CI: 78.9-100), respectively, at an optimum cut-off point of ≤ 6.50. Therefore, diastolic dysfunction determined by E' is a good independent outcome predictor.

Time course of fluid responsiveness in sepsis: the fluid challenge revisiting (FCREV) study

BACKGROUND

Fluid challenge (FC) is one of the most common practices in Intensive Care Unit (ICU). The present study aimed to evaluate whether echocardiographic assessment of the response to FC at the end of the infusion or 20 min later could affect the results of the FC.

METHODS

This is a prospective, observational, multicenter study including all ICU patients in septic shock requiring a FC of 500 mL crystalloids over 10 min. Fluid responsiveness was defined as a > 15% increase in stroke volume (SV) assessed by velocity-time integral (VTI) measurements at baseline (T0), at the end of FC (T10), then 10 (T20) and 20 min (T30) after the end of FC.

RESULTS

From May 20, 2014, to January 7, 2016, a total of 143 patients were enrolled in 11 French ICUs (mean age 64 ± 14 years, median IGS II 53 [43-63], median SOFA score 10 [8-12]). Among the 76/143 (53%) patient responders to FC at T10, 37 patients were transient responders (TR), i.e., became non-responders (NR) at T30 (49%, 95%CI = [37-60]), and 39 (51%, 95%CI = [38-62]) patients were persistent responders (PR), i.e., remained responders at T30. Among the 67 NR at T10, 4 became responders at T30, (6%, 95%CI = [1.9-15.3]). In the subgroup analysis, no statistical difference in hemodynamic and echocardiographic parameters was found between groups.

CONCLUSIONS

This study shows that 51.3% of initial responders have a persistent response to fluid 30 min after the beginning of fluid infusion and only 41.3% have a transient response highlighting that fluid responsiveness is time dependent.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02116413 . Registered on April 16, 2014.

Évaluation de la fonction diastolique du ventricule gauche en réanimation pédiatrique : quelles indications, quels paramètres mesurer ?

L’incidence des patients avec une insuffisance cardiaque diastolique a augmenté au cours des dernières années. De nombreuses études épidémiologiques, physiopathologiques, cliniques ou pronostiques ont été menées pour comprendre cette nouvelle entité. L’étude et l’analyse de la fonction diastolique (FD) sont devenues des temps essentiels de l’examen échocardiographique. Cet article a pour objectifs : 1) de faire le point sur la physiologie de la FD du ventricule gauche (VG) et sur son évaluation chez l’enfant ; 2) d’envisager des applications cliniques en réanimation pédiatrique pour lesquelles son évaluation est importante. L’évaluation de la FD du VG est complexe, en plein essor et encore peu réalisée en pédiatrie. De plus, la tachycardie chez l’enfant et les particularités pédiatriques encore méconnues rendent difficile l’analyse de certains paramètres. L’ETT est l’examen complémentaire incontournable pour évaluer la FD du VG, mais en cours d’étude chez l’enfant. L’évaluation de la FD du VG devrait faire partie intégrante des paramètres échocardiographiques à prendre en considération pour certaines situations (évaluation de la réponse au remplissage vasculaire et de la sevrabilité à la ventilation mécanique, ajustement des traitements…) afin de mieux comprendre sa mesure et l’utiliser en routine clinique. On retiendra que pour l’évaluation échocardiographique chez l’enfant de réanimation : dans un premier temps évaluer la fonction systolique puis s’efforcer d’évaluer l’évolution de la FD par les pressions de remplissage par des paramètres simples (doppler mitral et tissulaire) ajustés au Z-score (urihttp://www.parameterz.comhttp://www.parameterz.com) tels que les rapports E/e’ et E/A, le volume indexé de l’OG, le tout assorti au contexte clinique et à la cinétique des paramètres biologiques (BNP, NT pro-BNP).

Pathophysiology, echocardiographic evaluation, biomarker findings, and prognostic implications of septic cardiomyopathy: a review of the literature

BACKGROUND

Sepsis is a common condition encountered by emergency and critical care physicians, with significant costs, both economic and human. Myocardial dysfunction in sepsis is a well-recognized but poorly understood phenomenon. There is an extensive body of literature on this subject, yet results are conflicting and no objective definition of septic cardiomyopathy exists, representing a critical knowledge gap.

OBJECTIVES

In this article, we review the pathophysiology of septic cardiomyopathy, covering the effects of key inflammatory mediators on both the heart and the peripheral vasculature, highlighting the interconnectedness of these two systems. We focus on the extant literature on echocardiographic and laboratory assessment of the heart in sepsis, highlighting gaps therein and suggesting avenues for future research. Implications for treatment are briefly discussed.

CONCLUSIONS

As a result of conflicting data, echocardiographic measures of left ventricular (systolic or diastolic) or right ventricular function cannot currently provide reliable prognostic information in patients with sepsis. Natriuretic peptides and cardiac troponins are of similarly unclear utility. Heterogeneous classification of illness, treatment variability, and lack of formal diagnostic criteria for septic cardiomyopathy contribute to the conflicting results. Development of formal diagnostic criteria, and use thereof in future studies, may help elucidate the link between cardiac performance and outcomes in patients with sepsis.

Basic and advanced echocardiographic evaluation of myocardial dysfunction in sepsis and septic shock

Sepsis continues to be a leading cause of mortality and morbidity in the intensive care unit. Cardiovascular dysfunction in sepsis is associated with worse short- and long-term outcomes. Sepsis-related myocardial dysfunction is noted in 20%-65% of these patients and manifests as isolated or combined left or right ventricular systolic or diastolic dysfunction. Echocardiography is the most commonly used modality for the diagnosis of sepsis-related myocardial dysfunction. With the increasing use of ultrasonography in the intensive care unit, there is a renewed interest in sepsis-related myocardial dysfunction. This review summarises the current scope of literature focused on sepsis-related myocardial dysfunction and highlights the use of basic and advanced echocardiographic techniques for the diagnosis of sepsis-related myocardial dysfunction and the management of sepsis and septic shock.

Pearls and pitfalls in comprehensive critical care echocardiography

Critical care echocardiography is developing rapidly with an increasing number of specialists now performing comprehensive studies using Doppler and other advanced techniques. However, this imaging can be challenging, interpretation is far from simple in the complex critically ill patient and mistakes can be easy to make. We aim to address clinically relevant areas where potential errors may occur and suggest methods to hopefully improve accuracy of imaging and interpretation.

Echodynamics: Interpretation, Limitations, and Clinical Integration!

Echodynamics refers to the use of echocardiography as hemodynamic tool mostly in intensive and acute care settings. It implies a smooth drift from the classic cardiology use to a more critical care adjusted use. A more personalized approach is advocated in critical care, and echo is one way to reach such goal. Correct application necessitates optimum understanding, interpretation, and finally integration into patients' clinical management. As more critical care doctors are advancing from basic focused echo examinations to a more advanced one, this article is trying to underlie many pitfalls of critical care echocardiography in order to guide better practice.

Impact of New-Onset Left Ventricular Dysfunction on Outcomes in Mechanically Ventilated Patients With Severe Sepsis and Septic Shock

BACKGROUND:

Left ventricular systolic dysfunction (LVSD) and LV diastolic dysfunction (LVDD) are commonly seen in severe sepsis and septic shock; however, their role in patients with concurrent invasive mechanical ventilation (IMV) is less well defined.

METHODS:

This was a prospective observational study on all patients admitted to all the intensive care units (ICUs) at Mayo Clinic, Rochester from August 2007 to January 2009. All adult patients with severe sepsis and septic shock and concurrent IMV without prior heart failure underwent transthoracic echocardiography within 24 hours. Patients with active pregnancy, prior congenital or valvular heart disease, and prosthetic cardiac valves were excluded. Left ventricular systolic dysfunction was defined as LV ejection fraction (LVEF) <50% and LVDD as E/e' >15. Primary outcome was hospital mortality, and secondary outcomes included IMV duration, ICU length of stay (LOS), and total LOS. Two-tailed P value of <.05 was considered statistically significant.

RESULTS:

In a total of 106 patients, 58 (54.7%) met our inclusion criteria, with 17 (29.3%), 11 (19.0%), and 5 (8.6%) having LVSD, LVDD, and both, respectively. The cohorts with and without LVSD and LVDD did not differ significantly in their baseline characteristics and laboratory and ventilatory parameters. Compared to those without LVSD, patients with LVSD had higher LV end-systolic diameters but were not different in their left atrial diameters or E/e' ratio. Patients with LVDD had a higher E velocity and E/e' ratio compared to those without LVDD. Hospital mortality was not different in patients with and without LVSD (8 [47%] vs 21 [51%], P = 1.00) and LVDD (8 [73%] vs 21 [45%], P = .18). Secondary outcomes were not different between the 2 groups.

CONCLUSION:

Left ventricular systolic or diastolic dysfunction did not influence in-hospital outcomes in patients with severe sepsis and septic shock and concurrent IMV.

Diastolic dysfunction in the critically ill patient

Left ventricular diastolic dysfunction is a common finding in critically ill patients. It is characterized by a progressive deterioration of the relaxation and the compliance of the left ventricle. Two-dimensional and Doppler echocardiography is a cornerstone in its diagnosis. Acute pulmonary edema associated with hypertensive crisis is the most frequent presentation of diastolic dysfunction critically ill patients. Myocardial ischemia, sepsis and weaning failure from mechanical ventilation also may be associated with diastolic dysfunction. The treatment is based on the reduction of pulmonary congestion and left ventricular filling pressures. Some studies have found a prognostic role of diastolic dysfunction in some diseases such as sepsis. The present review aims to analyze thoroughly the echocardiographic diagnosis and the most frequent scenarios in critically ill patients in whom diastolic dysfunction plays a key role.

Prognostic impact of left ventricular diastolic function in patients with septic shock

Background

Left ventricular (LV) diastolic dysfunction is highly prevalent in the general population and associated with a significant morbidity and mortality. Its prognostic role in patients sustaining septic shock in the intensive care unit (ICU) remains controversial. Accordingly, we investigated whether LV diastolic function was independently associated with ICU mortality in a cohort of septic shock patients assessed using critical care echocardiography.

Methods

Over a 5-year period, patients hospitalized in a Medical–Surgical ICU who underwent an echocardiographic assessment with digitally stored images during the initial management of a septic shock were included in this retrospective single-center study. Off-line echocardiographic measurements were independently performed by an expert in critical care echocardiography who was unaware of patients’ outcome. LV diastolic dysfunction was defined by the presence of a lateral E′ maximal velocity <10 cm/s. A multivariate analysis was performed to determine independent risk factors associated with ICU mortality.

Results

Among the 540 patients hospitalized in the ICU with septic shock during the study period, 223 were studied (140 men [63 %]; age 64 ± 13 years; SAPS II 55 ± 18; SOFA 10 ± 3; Charlson 3.5 ± 2.5) and 204 of them (91 %) were mechanically ventilated. ICU mortality was 35 %. LV diastolic dysfunction was observed in 31 % of patients. The proportion of LV diastolic dysfunction tended to be higher in non-survivors than in their counterparts (28/78 [36 %] vs. 41/145 [28 %]: p = 0.15). Inappropriate initial antibiotic therapy (OR 4.17 [CI 95 % 1.33–12.5]: p = 0.03), maximal dose of vasopressors (OR 1.38 [CI 95 % 1.16–1.63]: p = 0.01), SOFA score (OR 1.16 [CI 95 % 1.02–1.32]: p = 0.02) and lateral E′ maximal velocity (OR 1.12 [CI 95 % 1.01–1.24]: p = 0.02) were independently associated with ICU mortality. After adjusting for the SAPS II score, inappropriate initial antibiotic therapy and maximal dose of vasopressors remained independent factors for ICU mortality, whereas a trend was only observed for lateral E′ maximal velocity (OR 1.11 [CI 95 % 0.99–1.23]: p = 0.07).

Conclusion

The present study suggests that LV diastolic function might be associated with ICU mortality in patients with septic shock. A multicenter prospective study assessing a large cohort of patients using serial echocardiographic examinations remains required to confirm the prognostic value of LV diastolic dysfunction in septic shock.

Systematic review including re-analyses of 1148 individual data sets of central venous pressure as a predictor of fluid responsiveness

PURPOSE

Central venous pressure (CVP) has been shown to have poor predictive value for fluid responsiveness in critically ill patients. We aimed to re-evaluate this in a larger sample subgrouped by baseline CVP values.

METHODS

In April 2015, we systematically searched and included all clinical studies evaluating the value of CVP in predicting fluid responsiveness. We contacted investigators for patient data sets. We subgrouped data as lower (<8 mmHg), intermediate (8-12 mmHg) and higher (>12 mmHg) baseline CVP.

RESULTS

We included 51 studies; in the majority, mean/median CVP values were in the intermediate range (8-12 mmHg) in both fluid responders and non-responders. In an analysis of patient data sets (n = 1148) from 22 studies, the area under the receiver operating curve was above 0.50 in the <8 mmHg CVP group [0.57 (95% CI 0.52-0.62)] in contrast to the 8-12 mmHg and >12 mmHg CVP groups in which the lower 95% CI crossed 0.50. We identified some positive and negative predictive value for fluid responsiveness for specific low and high values of CVP, respectively, but none of the predictive values were above 66% for any CVPs from 0 to 20 mmHg. There were less data on higher CVPs, in particular >15 mmHg, making the estimates on predictive values less precise for higher CVP.

CONCLUSIONS

Most studies evaluating fluid responsiveness reported mean/median CVP values in the intermediate range of 8-12 mmHg both in responders and non-responders. In a re-analysis of 1148 patient data sets, specific lower and higher CVP values had some positive and negative predictive value for fluid responsiveness, respectively, but predictive values were low for all specific CVP values assessed.

Tissue Doppler indices of diastolic function in critically ill patients and association with mortality - a systematic review

PURPOSE

Systolic impairment is well reported in critically ill patients but diastolic function has been relatively understudied. The objective of this review was to assess tissue Doppler indices of diastolic function in critically ill patients along with any association with mortality.

METHODS

A systematic review of articles in English using Medline, EMBASE, CINAHL and the Cochrane database of systematic reviews. Search terms included diastolic function, diastolic dysfunction, diastolic abnormal*, diastolic heart failure, diastolic filling, ventricular relaxation, pulmonary artery occlusion pressure, left ventricular filling pressure, cardiac dysfunction, intensive care, critical care, critically ill, critical illness, sepsis and septic shock. Only studies of critically ill adult patients (excluding post-cardiac surgical patients) whose diastolic function was assessed using tissue Doppler imaging were included. Study quality was assessed using a modified version of the Newcastle-Ottawa Scale (NOS).

RESULTS

Nineteen studies were included, with a total of 1365 patients. All trials were observational. There was a large heterogeneity in patient populations and the methodology of tissue Doppler assessment of diastology resulting in a descriptive analysis. Patient groups included severe sepsis or septic shock (5 studies), septic shock (5 studies), systemic inflammatory response syndrome and shock (1 study), septic shock and acute lung injury (1 study), cancer and septic shock (2 studies), general ICU patients (1 study), combined medical and surgical ICU (2 studies) and sub-arachnoid haemorrhage patients (2 studies). Seventeen studies scored 5/6 on the NOS with the remaining two scoring 4/6. Fourteen studies reported on numbers of patients diagnosed with diastolic dysfunction (500/999, mean 50%, range 20-92%). Three studies found that diastolic dysfunction was an independent predictor of mortality.

CONCLUSIONS

Current data shows a large range in the incidence of diastolic dysfunction in this patient population and a variable link with mortality. Future research should focus on the definition of normal values for diastolic function in critically ill patients along with the effects of ICU therapies and consensus criteria for its assessment in this patient population.

Variability in echocardiographic measurements of left ventricular function in septic shock patients

Background

Echocardiography is increasingly used for haemodynamic evaluation and titration of therapy in intensive care, warranting reliable and reproducible measurements. The aim of this study was to evaluate the observer dependence of echocardiographic findings of left ventricular (LV) diastolic and systolic dysfunction in patients with septic shock.

Methods

Echocardiograms performed in 47 adult patients admitted with septic shock to a general intensive care unit (ICU) were independently evaluated by one cardiologist and one intensivist for the following signs: decreased diastolic tissue velocity of the base of the LV septum (é), increased early mitral inflow (E) to é ratio (E/é), decreased LV ejection fraction (EF) and decreased LV global longitudinal peak strain (GLPS). Diastolic dysfunction was defined as é <8.0 cm/s and/or E/é ≥15 and systolic dysfunction as EF <50% and/or GLPS > −15%. Ten randomly selected examinations were re-analysed two months later. Pearson’s r was used to test the correlation and Bland-Altman plots to assess the agreement between observers. Kappa statistics were used to test the consistency between readers and intraclass correlation coefficients (ICC) for inter- and intraobserver variability.

Results

In 44 patients (94%), image quality was sufficient for echocardiographic measurements. The agreement between observers was moderate (k = 0.60 for é, k = 0.50 for E/é and k = 0.60 for EF) to good (k = 0.71 for GLPS). Pearson’s r was 0.76 for é, 0.85 for E/é, 0.78 for EF and 0.84 for GLPS (p < 0.001 for all four). The ICC between observers for é was very good (0.85; 95% confidence interval (CI) 0.73-0.92), good for E/é (0.70; 95% CI 0.45 – 0.84), very good for EF (0.87; 95% CI 0.77 – 0.93), excellent for GLPS (0.91; 95% CI 0.74 – 0.95), and very good for all measures repeated by one of the observers. On Bland-Altman analysis, the mean differences and 95% limits of agreement for é, E/é, EF and GLPS were −0.01 (0.04 – 0.07), 2.0 (−14.2 – 18.1), 0.86 (−16 – 14.3) and 0.04 (−5.04 – 5.12), respectively.

Conclusions

Moderate observer-related differences in assessing LV dysfunction were seen. GLPS is the least user dependent and most reproducible echocardiographic measurement of LV function in septic shock.

Electronic supplementary material

The online version of this article (doi:10.1186/s12947-015-0015-6) contains supplementary material, which is available to authorized users.

Ultrasonic evaluation of the heart

PURPOSE OF REVIEW

To discuss the role of echocardiography for the hemodynamic evaluation of critically ill patients.

RECENT FINDINGS

In addition to its crucial role in evaluating heart abnormalities as in the classical cardiological approach, echocardiography is now frequently used by intensivists for noninvasive hemodynamic evaluation of the critically ill patient. Using echocardiography, it is possible to measure cardiac output, intravascular pressures and volumes, systolic and diastolic function of both ventricles, and preload responsiveness. This not only allows characterization of the precise nature of hemodynamic alterations in patients with circulatory and respiratory failure, but also provides guidance for hemodynamic optimization and optimization of ventilatory settings. There are now many data showing how echocardiography can be useful in detecting otherwise unrecognized myocardial depression in sepsis and right ventricular dysfunction in mechanically ventilated patients. The main limitation of echocardiography for hemodynamic monitoring is its intermittent nature. Hence, echocardiography is often combined with other monitoring devices, allowing continuous measurement of flow and triggering new echocardiographic evaluations.

SUMMARY

Echocardiography has now become an important tool for hemodynamic evaluation of the critically ill patient. Echocardiography should be performed in most patients with circulatory and respiratory failure.

Physiological changes after fluid bolus therapy in sepsis: a systematic review of contemporary data

Fluid bolus therapy (FBT) is a standard of care in the management of the septic, hypotensive, tachycardic and/or oliguric patient. However, contemporary evidence for FBT improving patient-centred outcomes is scant. Moreover, its physiological effects in contemporary ICU environments and populations are poorly understood. Using three electronic databases, we identified all studies describing FBT between January 2010 and December 2013. We found 33 studies describing 41 boluses. No randomised controlled trials compared FBT with alternative interventions, such as vasopressors. The median fluid bolus was 500 ml (range 100 to 1,000 ml) administered over 30 minutes (range 10 to 60 minutes) and the most commonly administered fluid was 0.9% sodium chloride solution. In 19 studies, a predetermined physiological trigger initiated FBT. Although 17 studies describe the temporal course of physiological changes after FBT in 31 patient groups, only three studies describe the physiological changes at 60 minutes, and only one study beyond this point. No studies related the physiological changes after FBT with clinically relevant outcomes. There is a clear need for at least obtaining randomised controlled evidence for the physiological effects of FBT in patients with severe sepsis and septic shock beyond the period immediately after its administration.

‘Just as water retains no shape, so in warfare there are no constant conditions’

Sun Tzu (‘The Art of War’)

Clinical relevance of pulse pressure variations for predicting fluid responsiveness in mechanically ventilated intensive care unit patients: the grey zone approach

INTRODUCTION

Pulse pressure variation (PPV) has been shown to predict fluid responsiveness in ventilated intensive care unit (ICU) patients. The present study was aimed at assessing the diagnostic accuracy of PPV for prediction of fluid responsiveness by using the grey zone approach in a large population.

METHODS

The study pooled data of 556 patients from nine French ICUs. Hemodynamic (PPV, central venous pressure (CVP) and cardiac output) and ventilator variables were recorded. Responders were defined as patients increasing their stroke volume more than or equal to 15% after fluid challenge. The receiver operating characteristic (ROC) curve and grey zone were defined for PPV. The grey zone was evaluated according to the risk of fluid infusion in hypoxemic patients.

RESULTS

Fluid challenge led to increased stroke volume more than or equal to 15% in 267 patients (48%). The areas under the ROC curve of PPV and CVP were 0.73 (95% confidence interval (CI): 0.68 to 0.77) and 0.64 (95% CI 0.59 to 0.70), respectively (P<0.001). A grey zone of 4 to 17% (62% of patients) was found for PPV. A tidal volume more than or equal to 8 ml.kg(-1) and a driving pressure (plateau pressure - PEEP) more than 20 cmH2O significantly improved the area under the ROC curve for PPV. When taking into account the risk of fluid infusion, the grey zone for PPV was 2 to 13%.

CONCLUSIONS

In ventilated ICU patients, PPV values between 4 and 17%, encountered in 62% patients exhibiting validity prerequisites, did not predict fluid responsiveness.

Prevalence and outcome of diastolic dysfunction in children with fluid refractory septic shock--a prospective observational study

OBJECTIVES

Our primary objective was to determine the prevalence and outcome of diastolic dysfunction in children with fluid refractory septic shock. The secondary objective was to determine possible early predictors of diastolic dysfunction.

DESIGN

Prospective observational study.

SETTING

PICU of a tertiary care teaching hospital.

PATIENTS

Consecutive children 17 years old or younger with fluid refractory septic shock and not on mechanical ventilation admitted to our ICU from June 2011 to August 2012 were included. Survivors were followed up till 1 year of discharge (July 2013).

INTERVENTIONS

Children were subjected to 2D echocardiography and qualitative cardiac troponin-T test within the first 6 hours of admission.

MEASUREMENTS AND MAIN RESULTS

A total of 56 children were included. Median age was 7 years (interquartile range, 1.5, 14) and majority (52%) were males. Most common underlying diagnoses were meningitis and pneumonia. The prevalence of diastolic dysfunction was 41.1% (95% CI, 27.8-54.4), and mortality rate was 43% in those with diastolic dysfunction. At 1-year follow-up, residual dysfunction was present in only one of 11 of the survivors (11%). On univariable analysis of possible early predictors of diastolic dysfunction, we observed that these children tended to have higher mean central venous pressure (13 vs 6; p < 0.0001) and greater positivity for cardiac troponin-T (70% vs 36%; p = 0.01) compared with others. Although factors such as duration of illness and diastolic blood pressure were also lower in children with diastolic dysfunction compared with others, the difference was not statistically significant. On multivariable analysis, only the variable central venous pressure remained significant (adjusted odds ratio, 1.6; 95% CI, 1.12-2.14; p = 0.008).

CONCLUSIONS

Diastolic dysfunction is common in children with fluid refractory septic shock, and immediate outcomes may be poorer in such patients. Increased central venous pressure after initial fluid resuscitation may be an early indicator of diastolic dysfunction and warrant urgent bedside echocardiography to guide further management.

Ventricular diastolic abnormalities in the critically ill

PURPOSE OF REVIEW

Left-ventricular diastolic dysfunction is associated with various conditions frequently encountered in ICU patients. Due to prolonged relaxation and increased left-ventricular stiffness, patients with diastolic dysfunction are at high risk of developing abrupt pulmonary venous congestion. The present review describes the clinical spectrum of left-ventricular diastolic abnormalities in ICU patients.

RECENT FINDINGS

Left-ventricular diastolic dysfunction is associated with a preserved ejection fraction in half of the patients presenting with acute pulmonary edema. These patients may have dramatic presentation, such as flash pulmonary edema during a hypertensive crisis. Left-ventricular diastolic dysfunction is frequently involved in patients who fail extubation and may trigger weaning pulmonary edema. Sepsis and myocardial ischemia may also be associated with left-ventricular diastolic dysfunction. The diagnosis of left-ventricular diastolic dysfunction practically relies on two-dimensional and Doppler echocardiography. Further large-scale clinical studies are needed to better characterize the prevalence, the clinical relevance and time-course of left-ventricular diastolic dysfunction in ICU patients.

SUMMARY

Left-ventricular diastolic dysfunction accounts for a growing proportion of cardiogenic pulmonary edema and weaning failure in ICU patients. It may be reversible when induced by sepsis or myocardial ischemia. Its prognostic value in the ICU settings remains to be further investigated.

Early diastolic dysfunction is associated with intensive care unit mortality in cancer patients presenting with septic shock

BACKGROUND

Cancer patients present a high risk of sepsis and are exposed to cardiotoxic drugs during chemotherapy. Myocardial dysfunction is common during septic shock and can be evaluated at bedside using echocardiography. The aim of this study was to identify early cardiac dysfunctions associated with intensive care unit (ICU) mortality in cancer patients presenting with septic shock.

METHODS

Seventy-two cancer patients admitted to the ICU underwent echocardiography within 48 h of developing septic shock. History of malignancies, anticancer treatments, and clinical characteristics were prospectively collected.

RESULTS

ICU mortality was 48%. Diastolic dysfunction (e' ≤8 cm s(-1)) was an independent echocardiographic parameter associated with ICU mortality {odds ratio (OR) 7.7 [95% confidence interval (CI), 2.58-23.38]; P<0.001}. Overall, three factors were independently associated with ICU mortality: sepsis-related organ failure assessment score at admission [OR 1.35 ( 95% CI, 1.05-1.74); P=0.017], occurrence of diastolic dysfunction [OR 16.6 (95% CI, 3.28-84.6); P=0.001], and need for conventional mechanical ventilation [OR 16.6 (95% CI, 3.6-77.15); P<0.001]. Diastolic dysfunction was not associated with exposure to cardiotoxic drugs.

CONCLUSIONS

Early diastolic dysfunction is a strong and independent predictor of mortality in cancer patients presenting with septic shock. It is not associated with exposure to cardiotoxic drugs. Further studies incorporating monitoring of diastolic function and therapeutic interventions improving cardiac relaxation need to be evaluated in cancer patients presenting with septic shock.