Assessment of right ventricular function

LA, Ghosh S, Reddy M. Sepsis-Induced Myocardial Dysfunction in Pediatric Septic Shock: Prevalence, Predictors, and Outcome-A Prospective Observational Study

There is a paucity of literature on the prevalence, predictors, prognostic markers, and outcomes of sepsis-induced myocardial dysfunction (SMD) in pediatric septic shock. The objectives of our study were to estimate the prevalence of SMD in pediatric septic shock by point-of-care functional echocardiography (POCFE) and to study the association of SMD with severity of illness, organ dysfunctions, and outcomes. This prospective, observational study was conducted over a period of 1 year (from July 2018 to July 2019) in a 12-bed, tertiary pediatric intensive care unit (PICU) of an academic and referral hospital in South India. Children presenting with septic shock were enrolled in the study. POCFE was done within 6 hours of PICU admission and patients were categorized as having SMD based on POCFE findings. The prevalence of SMD (left ventricle ± right ventricle) was 32% (32/100). More than half of the children (54.5%) died in SMD group, whereas only 7.5% died in non-SMD group ( p  < 0.001). SMD was associated with higher organ dysfunctions, worse patient outcomes, and was found to be an independent predictor of mortality. The median lactate levels were higher in SMD group (3.15 [2.7, 5] vs. 2 [1.3, 2.7], p  < 0.001) as compared with non-SMD group. We observed significantly lower median lactate clearance at 6 hours in SMD than non-SMD (30.0% [-14.44, 44.22] vs. 59.8% [45.83, 71.43], p  < 0.001). Lactate levels at 6 hours with a threshold of 2.4 mmol/L was a good predictor of SMD with sensitivity and specificity of 73 and 80%, respectively. SMD is not an uncommon entity in children with septic shock. SMD was associated with worse patient outcomes, organ dysfunction, and mortality. Serum lactate trends may predict SMD and can be used as prognosticate markers as well.

Monitoring a Mystery: The Unknown Right Ventricle during Left Ventricular Unloading with Impella in Patients with Cardiogenic Shock

Background: Right ventricular (RV) dysfunction or failure occurs in more than 30% of patients in cardiogenic shock (CS). However, the importance of timely diagnosis of prognostically relevant impairment of RV function is often underestimated. Moreover, data regarding the impact of mechanical circulatory support like the Impella on RV function are rare. Here, we investigated the effects of the left ventricular (LV) Impella on RV function. Moreover, we aimed to identify the most optimal and the earliest applicable parameter for bedside monitoring of RV function by comparing the predictive abilities of three common RV function parameters: the pulmonary artery pulsatility index (PAPi), the ratio of right atrial pressure to pulmonary capillary wedge pressure (RA/PCWP), and the right ventricular stroke work index (RVSWI). Methods: The data of 50 patients with CS complicating myocardial infarction, supported with different flow levels of LV Impella, were retrospectively analyzed. Results: Enhancing Impella flow (1.5 to 2.5 L/min ± 0.4 L/min) did not lead to a significant variation in PAPi (p = 0.717), RA/PCWP (p = 0.601), or RVSWI (p = 0.608), indicating no additional burden for the RV. PAPi revealed the best ability to connect RV function with global hemodynamic parameters, i.e., cardiac index (CI; p < 0.001, 95% CI: 0.181-0.663), pulmonary capillary wedge pressure (PCWP; p = 0.005, 95% CI: -6.721--1.26), central venous pressure (CVP; p < 0.001, 95% CI: -7.89-5.575), and indicators of tissue perfusion (central venous oxygen saturation (SvO2); p = 0.008, 95% CI: 1.096-7.196). Conclusions: LV Impella does not impair RV function. Moreover, PAPi seems to be to the most effective and valid predictor for early bedside monitoring of RV function.

Looking Back, Going Forward: Understanding Cardiac Pathophysiology from Pressure-Volume Loops

Knowing cardiac physiology is essential for health care professionals working in the cardiovascular field. Pressure-volume loops (PVLs) offer a unique understanding of the myocardial working and have become pivotal in complex pathophysiological scenarios, such as profound cardiogenic shock or when mechanical circulatory supports are implemented. This review provides a comprehensive summary of the left and right ventricle physiology, based on the PVL interpretation.

Prevalence and prognostic value of various types of right ventricular dysfunction in mechanically ventilated septic patients

Introduction

Right ventricle (RV) dilation in combination with elevated central venous pressure (CVP), which is a state of RV congestion, is seen as a sign of RV failure (RVF). On the other hand, RV systolic function is usually assessed by tricuspid annular plane systolic excursion (TAPSE) and fractional area change (FAC). This study aimed to investigate the prevalence and prognostic value of RVF and RV systolic dysfunction (RVSD) in septic patients.

Methods

Mechanically ventilated sepsis and septic shock patients were included. We collected haemodynamic and echocardiographic parameters as well as prognostic information including mechanical ventilation duration, length of ICU stay and 30-day mortality. RVF was defined as a right and left ventricular end-diastolic area ratio ≥ 0.6 in combination with CVP ≥ 8 mmHg. RVSD was defined as TAPSE < 16 mm or FAC < 35%.

Results

A total of 215 patients were enrolled in this study, and the patients were divided into 4 groups: patients with normal RV function (normal, n = 101), patients with RVF but without RVSD (RVF only, n = 38), patients with RVSD but without RVF (RVSD only, n = 44), and patients with combined RVF–RVSD (RVF/RVSD, n = 32). The RVF/RVSD group and RVSD only group had a lower cardiac index than the RVF only group and normal groups (p < 0.05). At 30 days after ICU admission, 50.0% of patients had died in the RVF/RVSD group, which was much higher than the mortality in the RVF only group (13.2%) and normal group (13.9%) (p < 0.05). In a Cox regression analysis, the presence of RVF/RVSD was independently associated with 30-day mortality (HR 3.004, 95% CI:1.370–6.587, p = 0.006). In contrast, neither the presence of RVF only nor the presence of RVSD only was associated with 30-day mortality (HR 0.951, 95% CI:0.305–2.960, p = 0.931; HR 1.912, 95% CI:0.853–4.287, p = 0.116, respectively).

Conclusion

The presence of combined RVF–RVSD was associated with 30-day mortality in mechanically ventilated septic patients. Additional studies are needed to confirm and expand this finding.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00902-9.

What are the echocardiographic findings of acute right ventricular strain that suggest pulmonary embolism?

INTRODUCTION

Pulmonary embolism (PE) is a potentially fatal disease encountered in the hospital setting. Prompt diagnosis and management can improve outcomes and survival. Unfortunately, a PE may be difficult to diagnose in a timely manner. Point-of-care ultrasound (POCUS) can assist in the evaluation for suspected PE by assessing for acute right ventricular strain. Physicians should thus be aware of these echocardiographic findings.

OBJECTIVE

This manuscript will review ten echocardiographic findings of right ventricular strain that may suggest a diagnosis of PE. It will provide a description of each finding along with the associated pathophysiology. It will also summarize the literature for the diagnostic utility of echocardiography for this indication, while providing reference parameters where applicable. Along with labeled images and video clips, the review will then illustrate how to evaluate for each of the ten findings, while offering pearls and pitfalls in this bedside evaluation.

DISCUSSION

The ten echocardiographic findings of right ventricular strain are: increased right ventricle: left ventricle size ratio, abnormal septal motion, McConnell's sign, tricuspid regurgitation, elevated pulmonary artery systolic pressure, decreased tricuspid annular plane systolic excursion, decreased S', pulmonary artery mid-systolic notching, 60/60 sign, and speckle tracking demonstrating decreased right ventricular free wall strain.

CONCLUSIONS

Physicians must recognize and understand the echocardiographic findings and associated pathophysiology of right ventricular strain. In the proper clinical context, these findings can point toward a diagnosis of PE and thereby lead to earlier initiation of directed management.

Electrocardiometry for Hemodynamic Categorization and Assessment of Fluid Responsiveness in Pediatric Septic Shock: A Pilot Observational Study

Aim

To evaluate the utility of noninvasive electrocardiometry (ICON®) for hemodynamic categorization and assessment of fluid responsiveness in pediatric septic shock.

Materials and methods

Pilot prospective observational study in a 12-bedded tertiary pediatric intensive care unit (PICU) in children aged between 2 months and 16 years with unresolved septic shock after a 20 mL/kg fluid bolus. Those with cardiac index (CI) <3.3 L/min/m² and systemic vascular resistance index (SVRI) >1600 dyn sec/cm⁵/m² were classified as vasoconstrictive shock–electrocardiometry (VCEC) and those with CI >5.5 L/min/m² and SVRI <1000 dyn sec/cm⁵/m² as vasodilated shock–electrocardiometry (VDEC). Fluid responsiveness was defined as a 10% increase in CI with a 20 mL/kg fluid bolus. Sepsis-induced myocardial dysfunction (SMD) was diagnosed on echocardiography. Outcomes studied included clinical shock resolution, length of PICU stay, and mortality.

Results

Thirty children were enrolled over 6 months with a median (interquartile range) age and pediatric risk of mortality (PRISM) III score of 87(21,108) months and 6.75(1.5,8.25), respectively; 14(46.6%) were boys and 4(13.3%) died. Clinically, 19(63.3%) children had cold shock and 11(36.7%) had warm shock; however, 16(53.3%) children had VDEC (including five with clinical cold shock) and 14(46.7%) had VCEC using electrocardiometry. Fluid responsiveness was seen in 16(53.3%) children, 10 in the VCEC group and 6 in the VDEC group. In the VCEC group, the responders had a significant rise in CI and a fall in SVRI, while the responders in the VDEC group had a significant rise in CI and SVRI. Fluid responders, compared to nonresponders, had a significantly higher stroke volume variation (SVV) before fluid bolus (24.1 ± 5.2% vs. 18.2 ± 3.5%, p < 0.001) and a higher reduction in SVV after fluid bolus (10.0 ± 2.8% vs. 6.0 ± 4.5%, p = 0.006), higher lactate clearance (p = 0.03) and lower vasoactive-inotropic score (p = 0.04) at 6 hours, higher percentage of clinical shock resolution at 6 (p = 0.01) and 12 hours (p = 0.01), and lesser mortality (p = 0.002). Five (16.6%) children with VCEC had SMD and were less fluid responsive (p = 0.04) with higher mortality (p = 0.01) compared to those without SMD.

Conclusions and clinical significance

Continuous, noninvasive hemodynamic monitoring using electrocardiometry permits hemodynamic categorization and assessment of fluid responsiveness in pediatric septic shock. This may provide real-time guidance for optimal interventions, and thus, improve the outcomes.

How to cite this article

Rao SS, Reddy M, Lalitha AV, Ghosh S. Electrocardiometry for Hemodynamic Categorization and Assessment of Fluid Responsiveness in Pediatric Septic Shock: A Pilot Observational Study. Indian J Crit Care Med 2021;25(2):185–192.

Physicians' abilities to obtain and interpret focused cardiac ultrasound images from critically ill patients after a 2-day training course

Background

This study aimed to determine whether a focused 2-day cardiac ultrasound training course could enable physicians to obtain and interpret focused cardiac ultrasound (FCU) images from critically ill patients.

Methods

We retrospectively reviewed the FCU images submitted by the physicians who attended a 2-day FCU training courses. Three experienced trainers reviewed the images separately. They determined whether the images were assessable and scored the images on an 8-point scale. They also decided whether the physicians provided correct responses for visual estimations of the left ventricular ejection fraction (LVEF) and right ventricle (RV) dilatation and septal motion.

Results

Among the 327 physicians, 291 obtained images that were considered assessable (89%). The scores for parasternal short-axis view were lower than those obtained for other transthoracic echocardiographic views, p < 0.001. More physicians provided incorrect appraisals of LVEF than of RV dilatation and septal motion (19.9% vs. 3.1%, p < 0.001). The percentages of incorrect answers by LVEF category were as follows: 34.8% on images of LVEF < 30, 24.7% on images of LVEF 30–54, and 16.4% on images of LVEF ≥55%, p < 0.001. A logistic regression analysis showed that patients with abnormal LVEF were associated with physicians’ incorrect assessment of LVEF, with an odds ratio of 1.923 (95% confidence interval (CI):1.071–3.456, p = 0.029).

Conclusions

A large proportion of physicians could obtain and interpret FCU images from critically ill patients after a 2-day training course. However, they still scored low on the parasternal short-axis view and were more likely to make an incorrect assessment of LVEF in patients with abnormal left ventricular systolic function.

Respiratory variations of inferior vena cava fail to predict fluid responsiveness in mechanically ventilated patients with isolated left ventricular dysfunction

Background

Respiratory variation of inferior vena cava is problematic in predicting fluid responsiveness in patients with right ventricular dysfunction. However, its effectiveness in patients with isolated left ventricular systolic dysfunction (ILVD) has not been reported. We aimed to explore whether inferior vena cava diameter distensibility index (dIVC) can predict fluid responsiveness in mechanically ventilated ILVD patients.

Methods

Patients admitted to the intensive care unit who were on controlled mechanical ventilation and in need of a fluid responsiveness assessment were screened for enrolment. Several echocardiographic parameters, including dIVC, tricuspid annular plane systolic excursion (TAPSE), left ventricular ejection fraction (LVEF), and LV outflow tract velocity–time integral (VTI) before and after passive leg raising (PLR) were collected. Patients with LV systolic dysfunction only (TAPSE ≥ 16 mm, LVEF < 50%) were considered to have isolated left ventricular systolic dysfunction (ILVD).

Results

One hundred and twenty-nine subjects were enrolled in this study, among them, 28 were labelled ILVD patients, and the remaining 101 were patients with normal LV function (NLVF). The value of dIVC in ILVD patients was as high as that in NLVF patients, (20% vs. 16%, p = 0.211). The ILVD group contained a much lower proportion of PLR responders than NLVF patients did (17.9% vs. 53.2%, p < 0.001). No correlation was detected between dIVC and ΔVTI in ILVD patients (r = 0.196, p = 0.309). dIVC was correlated with ΔVTI in NLVF patients (r = 0.722, p < 0.001), and the correlation was strengthened compared with that derived from all patients (p = 0.020). A receiver-operating characteristic (ROC) analysis showed that the area-under-the-curve (AUC) of dIVC for determining fluid responsiveness from ILVD patients was not statistically significant (p = 0.251). In NLVF patients, ROC analysis revealed an AUC of 0.918 (95% CI 0.858–0.978; p < 0.001), which was higher than the AUC derived from all patients (p = 0.033). Patients with LVEF below 40% had a lower ΔVTI and fewer PLR responders than those with LVEF 40–50% and LVEF above 50% (p < 0.001).

Conclusion

dIVC should be used with caution when critically ill patients on controlled mechanical ventilation display normal right ventricular function in combination with abnormal left ventricular systolic function.

Physicians' Ability to Visually Estimate Left Ventricular Ejection Fraction, Right Ventricular Enlargement, and Paradoxical Septal Motion After a 2-Day Focused Cardiac Ultrasound Training Course

OBJECTIVE

Focused cardiac ultrasound (FCU) can provide useful information for the management of shock and acute respiratory distress syndrome. This study aimed to determine whether a 2-day focused cardiac ultrasound training course could enable critical care physicians to interpret ultrasound images in terms of left ventricular ejection fraction (LVEF), ratio of right ventricular end-diastolic area to left ventricular end-diastolic area (R/LVEDA), and septal kinetics.

DESIGN

A prospective analysis of an image test score.

SETTING

Ultrasound training programs in 7 regions across China.

PARTICIPANTS

Two hundred forty-seven critical care physicians.

INTERVENTIONS

All participants received a 2-day FCU training, including 4 sessions of basic heart function appraisal, 3 sessions of hands-on practice, and 1 session of image interpretation.

MEASUREMENTS AND MAIN RESULTS

The post-training total scores were considerably higher than those of pretraining (75.6% v 58.9%, respectively, p < 0.001). After the course, the trainees obtained considerably higher scores on images with LVEF <30% than on images with LVEF 30% to 54% and LVEF ≥55% (100% v 60.0% and 60.0%, respectively, p < 0.001). The trainees obtained considerably higher scores on images with R/LVEDA >1 than on images with R/LVEDA 0.6 to 1 and R/LVEDA <0.6 (90.0% v 80.0% and 80.0%, p = 0.042 and p < 0.001, respectively). The trainees obtained considerably higher scores on images with paradoxical septal movement (PSM) than on images without PSM (100% v 75.0%, respectively, p < 0.001).

CONCLUSION

The physicians' abilities to assess LVEF, RV enlargement, and PSM improved after the training course, and they demonstrated more accurate estimations of the most obviously abnormal images.

Frequency and prognostic impact of basic critical care echocardiography abnormalities in patients with acute respiratory distress syndrome

Background

Among intensive care unit (ICU) patients with acute respiratory distress syndrome (ARDS), apart from acute cor pulmonale (ACP), the frequency and prognostic impact of basic critical care echocardiography (BCCE) abnormalities are not well defined.

Methods

Observational study of patients with ARDS, admitted from September 2012 to May 2014, who underwent BCCE within 48 h of admission to a 20-bed medical ICU. We examined the association of two major BCCE-detected abnormalities (left ventricular ejection fraction < 40% and severe ACP) with ICU/hospital mortality and ICU/hospital length of stay. Multivariable models adjusted for age and illness severity.

Results

Of 234 patients with ARDS (age 62.3 ± 14.3 years; 88/37.6% female; APACHE II 26.8 ± 8.3; 26.5% ICU mortality; 32.1% hospital mortality), 94 (40.2%) had at least one major BCCE-detected abnormality. The more common major BCCE abnormality found was severe ACP (28.2%), followed by left ventricular ejection fraction < 40% (16.2%). On multivariate analysis, only severe ACP remained significantly associated with ICU/hospital mortality. Hospital mortality for mild, moderate and severe ARDS was 17.0, 27.9 and 50.0%, respectively (without severe ACP), and was 29.2, 48.3 and 53.8%, respectively (with severe ACP).

Conclusions

BCCE abnormalities were common, but only severe ACP had prognostic significance in ARDS, identifying patients who are at increased risk of ICU and hospital mortality. The presence of severe ACP appears to upstage ARDS severity by one level.

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.

Echocardiographic Evaluation of Hemodynamics in Neonates and Children

Hemodynamic instability and inadequate cardiac performance are common in critically ill children. The clinical assessment of hemodynamic status is reliant upon physical examination supported by the clinical signs such as heart rate, blood pressure, capillary refill time, and measurement of the urine output and serum lactate. Unfortunately, all of these parameters are surrogate markers of cardiovascular well-being and they provide limited direct information regarding the adequacy of blood flow and tissue perfusion. A bedside point-of-care echocardiography can provide real-time hemodynamic information by assessing cardiac function, loading conditions (preload and afterload) and cardiac output. The echocardiography has the ability to provide longitudinal functional assessment in real time, which makes it an ideal tool for monitoring hemodynamic assessment in neonates and children. It is indispensable in the management of patients with shock, pulmonary hypertension, and patent ductus arteriosus. The echocardiography is the gold standard diagnostic tool to assess hemodynamic stability in patients with pericardial effusion, cardiac tamponade, and cardiac abnormalities such as congenital heart defects or valvar disorders. The information from echocardiography can be used to provide targeted treatment in intensive care settings such as need of fluid resuscitation versus inotropic support, choosing appropriate inotrope or vasopressor, and in providing specific interventions such as selective pulmonary vasodilators in pulmonary hypertension. The physiological information gathered from echocardiography may help in making timely, accurate, and appropriate diagnosis and providing specific treatment in sick patients. There is no surprise that use of bedside point-of-care echocardiography is rapidly gaining interest among neonatologists and intensivists, and it is now being used in clinical decision making for patients with hemodynamic instability. Like any other investigation, it has certain limitations and the most important limitation is its intermittent nature. Sometimes acquiring high quality images for precise functional assessment in a ventilated child can be challenging. Therefore, it should be used in conjunction with the existing tools (physical examination and clinical parameters) for hemodynamic assessment while making clinical decisions.

Evaluation of Right Ventricular Systolic Function in Patients With Chronic Pulmonary Heart Disease by 2-Dimensional Speckle-Tracking Echocardiography

OBJECTIVES

To investigate the value of 2-dimensional (2D) speckle-tracking echocardiography for assessing right ventricular (RV) systolic function in patients with chronic pulmonary heart disease (CPHD) and the correlation of its parameters with the right ventricular ejection fraction (RVEF) on cardiac magnetic resonance imaging (MRI).

METHODS

According to pulmonary arterial systolic pressure, 80 patients with CPHD and tricuspid regurgitation were divided into 2 groups: 42 with mild pulmonary hypertension (PH; 30-50 mm Hg) and 38 with moderate or severe PH (≥50 mm Hg); 41 control participants were recruited. All participants underwent 2D speckle-tracking echocardiography and cardiac MRI. The longitudinal peak systolic strain and longitudinal peak systolic strain rate were measured by echocardiography in each segment of the RV free wall and interventricular septum and compared with the RVEF on cardiac MRI.

RESULTS

Strain values in all segments of the RV free wall and interventricular septum were lower in the mild PH group than the control group (P < .05). Strain rate values in the apical segment of the RV free wall and basal segment of the interventricular septum were lower in the mild PH group than the control group (P< .05). Strain and strain rate values in all segments of the RV free wall and interventricular septum were lower in the moderate or severe PH group than the control group (P < .05). Strain and strain rate values in all segments of the RV free wall and interventricular septum were lower in the moderate or severe PH group than the mild PH group (P< .05). Strain and strain rate values in all segments of the RV free wall and the interventricular septum correlated with the RVEF (P < .001).

CONCLUSIONS

The ability of speckle-tracking echocardiography to directly monitor RV myocardial function may allow early sensitive detection of subclinical myocardial dysfunction in patients with CPHD, with better risk stratification and timely institution of therapy.

Serial measurements of troponin and echocardiography in patients with moderate-to-severe acute respiratory distress syndrome

PURPOSE

To assess the clinical significance of serial troponin I levels (measured in the first 72 hours from admission) in 42 consecutive patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Echocardiography and electrocardiogram testings were serially performed in the time window.

MATERIALS AND METHODS

Troponin I was measured every 12 hours in the first 72 hours from intensive care unit (ICU) admission. Echocardiography and electrocardiogram testings were serially performed in the same time window to clinically interpret Tn I levels.

RESULTS

Patients with admission positive Tn I (38.1%) showed higher values of systolic pulmonary hypertension (P = .013) associated with significantly lower values of tricuspid annular plane excursion (P = .011). Twenty-five patients (25/42, 59.5%) exhibited positive peak Tn I and at second echocardiographic assessment exhibited significant lower tricuspid annular plane excursion values (P = .005). At stepwise regression analysis the following variables were an independent predictor for in-ICU mortality: Pco2 (OR 1.08, 95% CI 1.011-1.161, P = .023), systolic pulmonary arterial hypertension (OR 0.83, 95% CI 0.701-0.977, P = .002), log peak Tn I (OR 3.56, 95% CI 1.045-12.132, P = .042).

CONCLUSIONS

In moderate-to-severe ARDS, serial troponin I assessment together with echocardiography evaluation helped to identify a subgroup at higher risk for in-ICU death. Moreover, troponin release can be related to right ventricular dysfunction, thus highlighting the clinical role of echocardiography in ARDS patients.

The potential role and limitations of echocardiography in acute respiratory distress syndrome

Bedside use of Doppler echocardiography is being featured as a promising, clinically useful tool in assessing the pulmonary circulation in patients with acute respiratory distress syndrome (ARDS). The present review is aimed at summarizing the available evidence obtained with echocardiography on right ventricle (RV) function and pulmonary circulation in ARDS and to highlight the potential of this technique in clinical practice (only articles in English language were considered). According to the available evidence on echocardiographic findings, the following conclusions can be drawn: (a) echocardiography (transthoracic and transesophageal) has a growing role in the management ARDS patients mainly because of the strict interactions between the lung (and ventilation) and the RV and pulmonary circulation; (b) there may be a continuum of alterations in RV size and function and pulmonary circulation which may end in the development of acute cor pulmonale, probably paralleling ARDS disease severity; and (c) the detection of acute cor pulmonale should prompt intensivists to tailor their ventilatory strategy to the individual patient depending on the echocardiography findings. Bearing in mind the clinical role and growing importance of echocardiography in ARDS and the available evidence on this topic, we present a flow chart including the parameters to be measured and the timing of echo exams in ARDS patients. Despite the important progress that echocardiography has gained in the evaluation of patients with ARDS, several open questions remain and echocardiography still appears to be underused in these patients. A more systematic use of echocardiography (mainly through shared protocols) in ARDS could help intensivists to tailor the optimal treatment in individual patients as well as highlighting the limits and potential of this methodology in patients with ALI.

Management of right heart failure in the critically ill

Right ventricular failure complicates several commonly encountered conditions in the intensive care unit. Right ventricular dilation and paradoxic movement of the interventricular septum on echocardiography establishes the diagnosis. Right heart catheterization is useful in establishing the specific cause and aids clinicians in management. Principles of treatment focus on reversal of the underlying cause, optimization of right ventricular preload and contractility, and reduction of right ventricular afterload. Mechanical support with right ventricular assist device or veno-arterial extracorporeal membrane oxygenation can be used in select patients who fail to improve with optimal medical therapy.

Effect of positive end-expiratory pressure on porcine right ventricle function assessed by speckle tracking echocardiography

Background

Right ventricle (RV) dysfunction and hypotension can be induced by high levels of positive end-expiratory pressure (PEEP). We sought to determine in an animal model if a novel ultrasound analysis technique: speckle tracking echocardiography (STE), could determine deterioration in RV function induced by PEEP and to compare this to a conventional method of RV analysis: fractional area change (FAC). STE is a sensitive, angle-independent method for describing cardiac deformation (‘strain’) and is particularly useful in analyzing RV function as has been shown in pulmonary hypertension cohorts.

Methods

Ten pigs, 40-90 kg, anaesthetized, fully mechanically ventilated at 6 ml/kg were subject to step-wise escalating levels of PEEP at two-minute intervals (0, 5, 10, 15, 20, 25 and 30cmH₂0). Intracardiac echocardiography was used to image the RV as transthoracic and transesophageal echocardiography did not give sufficient image quality or flexibility. Off-line STE analysis was performed using Syngo Velocity Vector Imaging (Seimens Medical Solutions Inc., USA). STE systolic parameters are RV free wall strain (RVfwS) and strain rate (RVfwSR) and the diastolic parameter RV free wall strain rate early relaxation (RVfwSRe)

Results

With escalating levels of PEEP there was a clear trend of reduction in STE parameters (RVfwS, RVfwSR, RVfwSRe) and FAC. Significant hypotension (fall in mean arterial blood pressure of 20 mmHg) occurred at approximately PEEP 15 cmH₂O. Comparing RVfwS, RVfwSR and RVfwSRe values at different PEEP levels showed a significant difference at PEEP 0 cmH₂O vs PEEP 10 cmH₂O and above. FAC only showed a significant difference at PEEP 0 cmH₂O vs PEEP 20 cmH₂O and above. 30% of pigs displayed dyssychronous RV free wall contraction at the highest PEEP level reached.

Conclusions

STE is a sensitive method for determining RV dysfunction induced by PEEP and deteriorated ahead of a conventional assessment method: FAC. RVfwS decreased to greater extent compared to baseline than FAC, earlier in the PEEP escalation process and showed a significant decrease before there was a clinical relevant decrease in mean arterial blood pressure. Studies in ICU patients using transthoracic echocardiography are warranted to further investigate the most sensitive echocardiography method for detecting RV dysfunction induced by mechanical ventilation.

A practical approach to goal-directed echocardiography in the critical care setting

Urgent cardiac ultrasound examination in the critical care setting is clinically useful. Application of goal-directed echocardiography in this setting is quite distinct from typical exploratory diagnostic comprehensive echocardiography, because the urgent critical care setting mandates a goal-directed approach. Goal-directed echocardiography most frequently aims to rapidly identify and differentiate the cause(s) of hemodynamic instability and/or the cause(s) of acute respiratory failure. Accordingly, this paper highlights 1) indications, 2) an easily memorized differential diagnostic framework for goal-directed echocardiography, 3) clinical questions that must be asked and answered, 4) practical issues to allow optimal image capture, 5) primary echocardiographic views, 6) key issues addressed in each view, and 7) interpretation of findings within the differential diagnostic framework. The most frequent indications for goal-directed echocardiography include 1) the spectrum of hemodynamic instability, shock, and pulseless electrical activity arrest and 2) acute respiratory failure. The differential diagnostic categories for hemodynamic instability can be remembered using the mnemonic ‘SHOCK’ (for Septic, Hypovolemic, Obstructive, Cardiogenic, and (K) combinations/other kinds of shock). RESP-F (for exacerbation of chronic Respiratory disease, pulmonary Embolism, ST changes associated with cardiac or pericardial disease, Pneumonia, and heart Failure) can be used for acute respiratory failure. The goals of goal-directed echocardiography in the unstable patient are: assessing global ventricular systolic function, identifying marked right ventricular and left ventricular enlargement, assessing intravascular volume, and the presence of a pericardial effusion. In an urgent or emergent setting, it is recommended to go directly to the best view, which is frequently the subcostal or apical view. The five views are the subcostal four-chamber view, subcostal inferior vena cava view, parasternal long axis view, parasternal short axis view, and the apical four chamber view. Always interpret goal-directed echocardiographic findings in the context of clinically available hemodynamic information. When goal-directed echocardiography is insufficient or when additional abnormalities are appreciated, order a comprehensive echocardiogram. Goal-directed echocardiography and comprehensive echocardiography are not to be used in conflict with each other.

Pulmonary Arterial Hypertension in Intensive Care Unit

For the intensive care unit (ICU) physician, the diagnosis of pulmonary arterial hypertension (PAH) is difficult as it can easily be confounded with other forms of pulmonary hypertension (PH). The key issue is that PAH is a form of PH. On the opposite, PH does not automatically imply PAH. Pulmonary arterial hypertension must be differentiated from other causes of PH that are frequently seen in ICU. It was recently emphasized that pulmonary veno-occlusive disease (PVOD) must be differentiated from PH and PAH. The prognosis of PAH was consistently improved in the ten past years by introduction of selective pulmonary vasodilators and management by highly specialized medical teams. In ICU patients, PAH remains a severe disease with a high mortality rate. When PAH is suspected, a systematic diagnosis approach is of particular importance in order to rapidly eliminate left cardiac, thromboembolic and pulmonary causes of PH. Left cardiac disease is the most common cause of PH. Early recognition of PAH allows a rapid introduction of selective pulmonary vasodilators that can improve outcome. Idiopathic PAH is the most frequent cause but it can also be associated with scleroderma, HIV infection, anorexigen toxicity, thyroid disease, cirrhosis. Pulmonary vasodilators should be only a part of a general management including treatment of triggering factors, optimization of fluid balance, decrease of RV afterload by using pulmonary vasodilators while maintaining cardiac output and mean arterial pressure. The early contact of PH referral center or specialized physician is of particular importance.

Multimodal monitoring for hemodynamic categorization and management of pediatric septic shock: a pilot observational study*

OBJECTIVES

To evaluate the cardiovascular aberrations using multimodal monitoring in fluid refractory pediatric septic shock and describe the clinical characteristics of septic myocardial dysfunction.

DESIGN

Prospective observational study of patients with unresolved septic shock after infusion of 40 mL/kg fluid in the first hour.

SETTING

Two tertiary care referral Indian PICUs.

PATIENTS

Patients aged 1 month to 16 years who had fluid refractory septic shock.

INTERVENTIONS

Changes in therapy were based on findings of clinical assessment, bedside echocardiography, and invasive blood pressure monitoring within 6 hours of recognition of septic shock.

MEASUREMENTS AND MAIN RESULTS

Over a 4-year period, 48 patients remained in septic shock despite at least 40 mL/kg fluid infusion. On clinical examination, 21 patients had cold shock and 27 had warm shock. Forty-one patients (85.5%) had vasodilatory shock on invasive blood pressure; these included 14 patients who initially presented with cold shock. The commonest echocardiography findings were impaired left ± right ventricular function in 19 patients (39.6%) and hypovolemia in 16 patients (33%). Three patients who had normal myocardial function on day 1 developed secondary septic myocardial dysfunction on day 3. Echocardio graphy, along with invasive arterial pressure monitoring, allowed fluid, inotropy, and pressors to be titrated more precisely in 87.5% of patients. Shock resolved in 46 of 48 patients (96%) and 44 patients (91.6%) survived to discharge.

CONCLUSION

Bedside echocardiography provided crucial information leading to the recognition of septic myocardial dysfunction and uncorrected hypovolemia that was not apparent on clinical assessment. With invasive blood pressure monitoring, echocardiography affords a simple noninvasive tool to determine the cause of low cardiac output and the physiological basis for adjustment of therapy in patients who remain in shock despite 40 mL/kg fluid.

Pleural effusions on the intensive care unit; hidden morbidity with therapeutic potential

Despite 50-60% of intensive care patients demonstrating evidence of pleural effusions, there has been little emphasis placed on the role of effusions in the aetiology of weaning failure. Critical illness and mechanical ventilation lead to multiple perturbations of the normal physiological processes regulating pleural fluid homeostasis, and consequently, failure of normal pleural function occurs. Effusions can lead to deleterious effects on respiratory mechanics and gas exchange, and when extensive, may lead to haemodynamic compromise. The widespread availability of bedside ultrasound has not only facilitated earlier detection of pleural effusions but also safer fluid sampling and drainage. In the majority of patients, pleural drainage leads to improvements in lung function, with data from spontaneously breathing individuals demonstrating a consistent symptomatic improvement, while a meta-analysis in critically ill patients shows an improvement in oxygenation. The effects on respiratory mechanics are less clear, possibly reflecting heterogeneity of underlying pathology. Limited data on clinical outcome from pleural fluid drainage exist; however, it appears to be a safe procedure with a low risk of major complications. The current level of evidence would support a clinical trial to determine whether the systematic detection and drainage of pleural effusions improve clinical outcomes.

A novel case of transient right ventricular failure in a patient with respiratory distress

Right ventricular (RV) failure is characterized by an inability to pump blood into the pulmonary circulation and can often lead to hemodynamic instability. Common causes of RV failure include left ventricular (LV) failure, RV infarction, sepsis, cor pulmonale due to acute respiratory distress syndrome, pulmonary emboli, or pulmonary hypertension. We report the case of a 61-year-old woman with no significant pulmonary or cardiac disease who presented with hypoxic respiratory failure in the setting of opioid overdose. She remained obtunded despite naloxone treatment and required endotracheal intubation as well as norepinephrine therapy for persistent hypotension. A transthoracic echocardiogram demonstrated isolated severe RV dysfunction without any LV abnormalities. Cardiac catheterization showed no obstructive coronary artery disease, pulmonary hypertension, or elevated left atrial pressures, and chest imaging only revealed signs of aspiration. Over the next 6 days, the patient's cardiac and respiratory function improved, and a repeat echocardiogram demonstrated complete normalization of RV function. This case demonstrates a novel finding that marked, but transient, RV dysfunction can occur in the setting of acute respiratory failure.

Right Ventricular Dysfunction in Sepsis

Current Surviving Sepsis Campaign guidelines inadequately address the limitations of central venous pressure monitoring, which are due, in part, to right and left ventricular dysfunction associated with sepsis. Septic cardiomyopathy is well described in the literature but is both underrecognized and undertreated clinically. Direct cardiac assessment with transesophageal echocardiography (TEE) has documented advantages, but is limited by single evaluations and the need for advanced training. Recently, a disposable, monoplane TEE probe that provides for serial echocardiographic assessments in unstable patients to guide medical management, or hemodynamic TEE (hTEE), has been introduced. This article reviews a case of a 48-year-old gentleman with a history of smoking, chronic obstructive pulmonary disease, and Child’s A cirrhosis who underwent an uneventful off-pump coronary artery bypass grafting and 2 days later developed septic shock from pneumonia complicated by right ventricular dysfunction. hTEE provided a rational guide to fluid resuscitation, vasopressor, and inotropic therapy with ensuing patient convalescence. Although there is a lack of hTEE experience among current intensivists, there is a desire to learn echocardiography as witnessed by the success of echocardiography courses and interest among critical care fellows. Future work to assess echocardiographic hemodynamic protocols and their effect on outcomes will be important.

Haemodynamic monitoring using echocardiography in the critically ill: a review

Physicians caring for the critically ill are now expected to acquire competence in echocardiography. It has become an indispensable diagnostic and monitoring tool in acute care settings where it is generally accepted to have therapeutic impact. There are a number of indications for a critical care echocardiographic study, and the most important queries include those pertaining left and right ventricular function and filling status. Focused examinations are increasing in popularity and provide a means for systematic study, and can be easily learned and practiced by novices. This paper addresses the indications, therapeutic impact, and some of the most common questions that can be answered using echocardiography the in critically ill patient.

Thermodilution-derived indices for assessment of left and right ventricular cardiac function in normal and impaired cardiac function

OBJECTIVE

The aim of this study was to assess whether thermodilution-derived parameters of right and left ventricular cardiac function (right ventricular ejection fraction, global ejection fraction, cardiac function index) are able to track changes of cardiac contractile function and whether they are influenced by substantial preload reduction.

DESIGN

Prospective animal study.

SETTING

University-affiliated animal research laboratory.

SUBJECTS

Domestic pigs.

INTERVENTIONS

Sixteen domestic pigs were studied. Right ventricular ejection fraction, global ejection fraction, and cardiac function index were compared to direct measurement of left ventricular rate of maximum systolic pressure rise and the left ventricular rate of maximum systolic pressure rise corrected to preload. Measurements were done with normal cardiac function during normo- and hypovolemia. Thereafter, cardiac function was impaired by continuous infusion of verapamil and measurements were repeated during normo- and hypovolemia (withdrawal of blood 20 mL kg body weight).

MEASUREMENTS AND MAIN RESULTS

With normal cardiac function, hypovolemia led to a significant decrease of right ventricular ejection fraction from 36.7% ± 6.6% to 29.8% ± 5.8% (p < .001), global ejection fraction from 40.5% ± 6.2% to 33.6% ± 7.6% (p < .001), and the left ventricular rate of maximum systolic pressure rise from 2104 ± 390 mm Hg sec to 1297 ± 438 mm Hg sec (p < .001). Cardiac function index (8.92 ± 2.20 min to 7.93 ± 1.54 min) and the left ventricular rate of maximum systolic pressure rise corrected to preload (18.2 ± 4.7 mm Hg sec mL to 15.2 ± 4.3 mm Hg sec mL) did not change significantly. Infusion of verapamil led to a significant reduction of right ventricular ejection fraction, global ejection fraction, cardiac function index, the left ventricular rate of maximum systolic pressure rise, and the left ventricular rate of maximum systolic pressure rise corrected to preload (p < .001). Now, hypovolemia led to a significant decrease of right ventricular ejection fraction (29.1% ± 4.6% to 24.9% ± 5.9%; p < .001), global ejection fraction (37.1% ± 4.7% to 31.9% ± 3.9%; p < .05), cardiac function index (7.58 ± 1.02 to 6.27 ± 1.19 min; p < .05), and the left ventricular rate of maximum systolic pressure rise (733 ± 141 mm Hg sec to 426 ± 108 mm Hg sec; p < .05). Only the left ventricular rate of maximum systolic pressure rise corrected to preload did not change significantly (6.7 ± 1.3 mm Hg sec mL to 4.6 ± 1 mm Hg sec mL; p > .05).

CONCLUSIONS

Right ventricular ejection fraction, global ejection fraction, and cardiac function index enable detection of changes in load-independent, intrinsic cardiac contractility. Importantly, they also reflect changes of contractile function caused by substantial decrease of preload, emphasizing the importance of assessing both cardiac contractile function in coherence with cardiac preload to differentiate between reduced intrinsic contractility and hypovolemia.

Passive leg raising can predict fluid responsiveness in patients placed on venovenous extracorporeal membrane oxygenation

Introduction

In ICUs, fluid administration is frequently used to treat hypovolaemia. Because volume expansion (VE) can worsen acute respiratory distress syndrome (ARDS) and volume overload must be avoided, predictive indicators of fluid responsiveness are needed. The purpose of this study was to determine whether passive leg raising (PLR) can be used to predict fluid responsiveness in patients with ARDS treated with venovenous extracorporeal membrane oxygenation (ECMO).

Methods

We carried out a prospective study in a university hospital surgical ICU. All patients with ARDS treated with venovenous ECMO and exhibiting clinical and laboratory signs of hypovolaemia were enrolled. We measured PLR-induced changes in stroke volume (ΔPLRSV) and cardiac output (ΔPLRCO) using transthoracic echocardiography. We also assessed PLR-induced changes in ECMO pump flow (ΔPLRPO) and PLR-induced changes in ECMO pulse pressure (ΔPLRPP) as predictors of fluid responsiveness. Responders were defined by an increase in stroke volume (SV) > 15% after VE.

Results

Twenty-five measurements were obtained from seventeen patients. In 52% of the measurements (n = 13), SV increased by > 15% after VE (responders). The patients' clinical characteristics appeared to be similar between responders and nonresponders. In the responder group, PLR significantly increased SV, cardiac output and pump flow (P < 0.001). ΔPLRSV values were correlated with VE-induced SV variations (r² = 0.72, P = 0.0001). A 10% increased ΔPLRSV predicted fluid responsiveness with an area under the receiver operating characteristic curve (AUC) of 0.88 ± 0.07 (95% confidence interval (CI₉₅): 0.69 to 0.97; P < 0.0001), 62% sensitivity and 92% specificity. On the basis of AUCs of 0.62 ± 0.11 (CI₉₅: 0.4 to 0.8; P = 0.31) and 0.53 ± 0.12 (CI₉₅: 0.32 to 0.73, P = 0.79), respectively, ΔPLRPP and ΔPLRPO did not predict fluid responsiveness.

Conclusions

In patients treated with venovenous ECMO, a > 10% ΔPLRSV may predict fluid responsiveness. ΔPLRPP and ΔPLRPO cannot predict fluid responsiveness.

Physiologic and Clinical Principles behind Noninvasive Resuscitation Techniques and Cardiac Output Monitoring

Clinical assessment and vital signs are poor predictors of the overall hemodynamic state. Optimal measurement of the response to fluid resuscitation and hemodynamics has previously required invasive measurement with radial and pulmonary artery catheterization. Newer noninvasive resuscitation technology offers the hope of more accurately and safely monitoring a broader range of critically ill patients while using fewer resources. Fluid responsiveness, the cardiac response to volume loading, represents a dynamic method of improving upon the assessment of preload when compared to static measures like central venous pressure. Multiple new hemodynamic monitors now exist that can noninvasively report cardiac output and oxygen delivery in a continuous manner. Proper assessment of the potential future role of these techniques in resuscitation requires understanding the underlying physiologic and clinical principles, reviewing the most recent literature examining their clinical validity, and evaluating their respective advantages and limitations.

Isolated double-chambered right ventricle in a young adult

Double-chambered right ventricle (DCRV) is a rare congenital heart disorder in which the right ventricle is divided by an anomalous muscle bundle into a high pressure inlet portion and a low pressure outlet portion. We report a case of isolated DCRV without symptoms in adulthood, diagnosed through echocardiography, cardiac catheterization and cardiac magnetic resonance imaging.

Pulmonary vascular and right ventricular dysfunction in adult critical care: current and emerging options for management: a systematic literature review

INTRODUCTION

Pulmonary vascular dysfunction, pulmonary hypertension (PH), and resulting right ventricular (RV) failure occur in many critical illnesses and may be associated with a worse prognosis. PH and RV failure may be difficult to manage: principles include maintenance of appropriate RV preload, augmentation of RV function, and reduction of RV afterload by lowering pulmonary vascular resistance (PVR). We therefore provide a detailed update on the management of PH and RV failure in adult critical care.

METHODS

A systematic review was performed, based on a search of the literature from 1980 to 2010, by using prespecified search terms. Relevant studies were subjected to analysis based on the GRADE method.

RESULTS

Clinical studies of intensive care management of pulmonary vascular dysfunction were identified, describing volume therapy, vasopressors, sympathetic inotropes, inodilators, levosimendan, pulmonary vasodilators, and mechanical devices. The following GRADE recommendations (evidence level) are made in patients with pulmonary vascular dysfunction: 1) A weak recommendation (very-low-quality evidence) is made that close monitoring of the RV is advised as volume loading may worsen RV performance; 2) A weak recommendation (low-quality evidence) is made that low-dose norepinephrine is an effective pressor in these patients; and that 3) low-dose vasopressin may be useful to manage patients with resistant vasodilatory shock. 4) A weak recommendation (low-moderate quality evidence) is made that low-dose dobutamine improves RV function in pulmonary vascular dysfunction. 5) A strong recommendation (moderate-quality evidence) is made that phosphodiesterase type III inhibitors reduce PVR and improve RV function, although hypotension is frequent. 6) A weak recommendation (low-quality evidence) is made that levosimendan may be useful for short-term improvements in RV performance. 7) A strong recommendation (moderate-quality evidence) is made that pulmonary vasodilators reduce PVR and improve RV function, notably in pulmonary vascular dysfunction after cardiac surgery, and that the side-effect profile is reduced by using inhaled rather than systemic agents. 8) A weak recommendation (very-low-quality evidence) is made that mechanical therapies may be useful rescue therapies in some settings of pulmonary vascular dysfunction awaiting definitive therapy.

CONCLUSIONS

This systematic review highlights that although some recommendations can be made to guide the critical care management of pulmonary vascular and right ventricular dysfunction, within the limitations of this review and the GRADE methodology, the quality of the evidence base is generally low, and further high-quality research is needed.