Outcomes of right heart dysfunction in the acutely and severely unwell: protocol for a prospective, longitudinal observational study using multimodal assessment.

INTRODUCTION: The relationship of acute right heart dysfunction (RHD) with long-term cardiopulmonary dysfunction and its' associated morbidity has not been clearly elucidated. We propose a prospective, observational study to assess the natural history of acute RHD using a combination of imaging, functional and qualitative assessment methods, including the recently described combination of simultaneous maximal effort cardiopulmonary exercise testing and stress echocardiography. METHODS AND ANALYSIS: We propose a single-centre study of patients ≥18 years admitted to either the intensive care or respiratory close observation units with RHD on transthoracic echocardiography (TTE). Participants will undergo a repeat TTE ~72 hours after the initial study, with a final TTE performed prior to discharge in patients who have a prolonged (>1 week) stay. Inpatient clinical, biochemical and therapeutic indices will be collected contemporaneously. At ~6 months postdischarge, participants will undergo evaluation with validated symptom assessment tools (Dyspnoea-12 and PAH-SYMPACT Questionnaires) and a combined maximal effort cardiopulmonary exercise test and stress echocardiogram. This study is an observational, hypothesis-generating study with a recruitment target of 100 patients established based on typical admission rates of the relevant hospital departments. Measures of central tendency and dispersion will be used to describe the cohort. Inferential statistics will be used to compare the two a priori defined groups of those whose RHD had resolved prior to hospital discharge and those whose dysfunction persisted at time of discharge. ETHICS AND DISSEMINATION: This study has received ethics approval from the local ethics committee (Nepean and Blue Mountains Local Health District approval, project 2021/ETH12111). Written informed consent will be sought from all patients prior to recruitment. The results will be submitted for publication in a relevant peer-reviewed journal and presented at an appropriate national/international conference. STUDY REGISTRATION: Australian New Zealand Clinical Trials Registry, ANZCTR12623000309684.

The PRICES statement: an ESICM expert consensus on methodology for conducting and reporting critical care echocardiography research studies.

PURPOSE: Echocardiography is a common tool for cardiac and hemodynamic assessments in critical care research. However, interpretation (and applications) of results and between-study comparisons are often difficult due to the lack of certain important details in the studies. PRICES (Preferred Reporting Items for Critical care Echocardiography Studies) is a project endorsed by the European Society of Intensive Care Medicine and conducted by the Echocardiography Working Group, aiming at producing recommendations for standardized reporting of critical care echocardiography (CCE) research studies. METHODS: The PRICE panel identified lists of clinical and echocardiographic parameters (the "items") deemed important in four main areas of CCE research: left ventricular systolic and diastolic functions, right ventricular function and fluid management. Each item was graded using a critical index (CI) that combined the relative importance of each item and the fraction of studies that did not report it, also taking experts' opinion into account. RESULTS: A list of items in each area that deemed essential for the proper interpretation and application of research results is recommended. Additional items which aid interpretation were also proposed. CONCLUSION: The PRICES recommendations reported in this document, as a checklist, represent an international consensus of experts as to which parameters and information should be included in the design of echocardiography research studies. PRICES recommendations provide guidance to scientists in the field of CCE with the objective of providing a recommended framework for reporting of CCE methodology and results.

Subcostal TAPSE: a retrospective analysis of a novel right ventricle function assessment method from the subcostal position in patients with sepsis.

BACKGROUND: Tricuspid annular plane systolic excursion (TAPSE) is frequently used as an objective measure of right-ventricular dysfunction. Abnormal TAPSE values are associated with poor prognosis in a number of disease states; however, the measure is not always easy to obtain in the critically ill. The purpose of this study is to assess the feasibility and accuracy of using a subcostal view and TAPSE measurement as a measure of right-ventricular dysfunction. A secondary aim was to perform a pilot study to assess whether right-ventricular dysfunction was associated with adverse outcomes including mortality. RESULTS: Subcostal TAPSE corresponds well with TAPSE obtained from the apical window at low and moderate TAPSE values (mean difference 1.2 mm (CI 0.04-2.36; 100% data pairs < 3-mm difference for TAPSE < 19 mm; 92% had < 3 mm difference at TAPDE < 24 mm). Subcostal TAPSE is able to accurately discriminate between abnormal and normal TAPSE results (sensitivity 97.8%, specificity 87.5%). There was no association between right-ventricular (RV) dysfunction and 90-day mortality. CONCLUSIONS: Subcostal TAPSE is a feasible and accurate alternative to conventional TAPSE from the apical view in critically ill patients. Further research is required to elucidate the relationship between RV dysfunction and outcomes in sepsis.

Feasibility of myocardial perfusion assessment with contrast echocardiography: can it improve recognition of significant coronary artery disease in the ICU?

BACKGROUND: Diagnosis of significant coronary artery disease (CAD) and acute coronary artery occlusion in ICU can be difficult, and an inappropriate intervention is potentially harmful. Myocardial contrast perfusion echo (MCPE) examines ultrasound contrast intensity replenishment curves in individual myocardial segments measuring peak contrast intensity and slope of return as an index of myocardial blood flow (units = intensity of ultrasound per second [dB/s]). MCPE could possibly serve as a triage tool to invasive angiography by estimating blood flow in the myocardium. We sought to assess feasibility in the critically ill and if MCPE could add incremental value to the clinical acumen in predicting significant CAD. METHODS: This is a single-centre, prospective, observational study. Inclusion criteria were as follows: adult ICU patients with troponin I > 50 ng/L and cardiology referral being made for consideration of inpatient angiography. Exclusion criteria were as follows: poor echo windows (2 patients), known ischaemic heart disease, and contrast contraindications. Seven cardiologists and 6 intensivists blinded to outcome assessed medical history, ECG, troponin, and 2D echo images to estimate likelihood of significant CAD needing intervention (clinical acumen). Clinical acumen, quantitative MCPE, and subjective (visual) MCPE were assessed to predict significant CAD. RESULTS: Forty patients underwent MCPE analysis, 6 (15%) had significant CAD, and median 11 of 16 segments (IQR 8-13) could be imaged (68.8% [IQR 50-81]). No adverse events occurred. A significant difference was found in overall MCPE blood flow estimation between those diagnosed with significant CAD and those without (3.3 vs 2.4 dB/s, p = 0.050). A MCPE value of 2.8 dB/s had 67% sensitivity and 88% specificity in detecting significant CAD. Clinical acumen showed no association in prediction of CAD (OR 0.6, p = 0.09); however, if quantitative or visual MCPE analysis was included, a significant association occurred (OR 17.1, p = 0.01; OR 23.0, p = 0.01 respectively). CONCLUSIONS: MCPE is feasible in the critically ill and shows better association with predicting significant CAD vs clinical acumen alone. MCPE adds incremental value to initial assessment of the presence of significant CAD which may help guide those who require urgent angiography.

Subjective right ventricle assessment by echo qualified intensive care specialists: assessing agreement with objective measures.

BACKGROUND: Right ventricle (RV) size and function assessment by echocardiography (echo) is a standard tool in the ICU. Frequently subjective assessment is performed, and guidelines suggest its utility in adequately trained clinicians. We aimed to compare subjective (visual) assessment of RV size and function by ICU physicians, with advanced qualifications in echocardiography, vs objective measurements. METHODS: ICU specialists with a qualification in advanced echocardiography reviewed 2D echo clips from critically ill patients on mechanical ventilation with PaO2:FiO2 < 300. Subjective assessments of RV size and function were made independently using a three-class categorical scale. Agreement (B-score) and bias (p value) were analysed using objective echo measurements. RV size assessment included RV end-diastolic area (EDA) and diameters. RV function assessment included fractional area change, S', TAPSE and RV free wall strain. Binary and ordinal analysis was performed. RESULTS: Fifty-two clinicians reviewed 2D images from 80 patients. Fair agreement was seen with objective measures vs binary assessment of RV size (RV EDA 0.26 [p < 0.001], RV dimensions 0.29 [p = 0.06]) and function (RV free wall strain 0.27 [p < 0.001], TAPSE 0.27 [p < 0.001], S' 0.29 [p < 0.001], FAC 0.31 [p = 0.16]). However, ordinal data analysis showed poor agreement with RV dimensions (0.11 [p = 0.06]) and RV free wall strain (0.14 [p = 0.16]). If one-step disagreement was allowed, agreement was good (RV dimensions 0.6 [p = 0.06], RV free wall strain 0.6 [p = 0.16]). Significant overestimation of severity of abnormalities was seen with subjective assessment vs RV EDA, TAPSE, S' and fractional area change. CONCLUSION: Subjective (visual) assessment of RV size and function, by ICU specialists trained in advanced echo, can be fairly reliable for the initial exclusion of significant RV pathology. It seems prudent to avoid subjective RV assessment in isolation.

Use of Angle-Independent M-Mode Sonography for Assessment of Diaphragm Displacement.

OBJECTIVES: Sonographic assessment of diaphragm displacement has conventionally been conducted with M-mode sonography via an anterior subcostal approach. This method is subject to measurement errors when diaphragm displacement is not in line with the M-mode plane. We aimed to compare measurements obtained by offline angle-independent (anatomic) M-mode sonography with conventional M-mode sonography. METHODS: Fifty healthy adults were imaged with conventional and angle-independent M-mode sonography of the bilateral hemidiaphragms at 60% maximal inspiratory capacity using an inspiratory spirometer. RESULTS: Left hemidiaphragm displacement was successfully imaged by conventional M-mode sonography in only 70% (n = 35), as lung expansion obscured imaging, whereas 92% (n = 46) were assessable by angle-independent M-mode sonography. All right hemidiaphragm displacement could be assessed. Conventional M-mode results were higher than angle-independent M-mode results on the right (mean ± SD, 4.9 ± 1.4 versus 4.6 ± 1.2 cm, respectively; P= .003) and left (5.4 ± 1.3 versus 4.6 ± 1.0 cm; P < .001). Displacement values were different for right versus left hemidiaphragms on conventional M-mode sonography (mean difference, 0.6 ± 0.2 cm; P = .005), with only mild agreement (R2 = 0.35; P < .001). There was no laterality seen in the diaphragm displacement on angle-independent M-mode sonography (mean difference, 0.1 ± 0.1 cm; P = .47), with good agreement (R2 = 0.76; P < .001). CONCLUSIONS: Angle-independent M-mode sonography leads to better visualization and assessment of the left hemidiaphragm. It records lower displacement than conventional M-mode sonography in the bilateral diaphragms, likely because of fewer orientation and translation errors. Future study is indicated to assess the clinical utility of angle-independent M-mode sonography in a population with diaphragm dysfunction.

Diaphragm assessment by two dimensional speckle tracking imaging in normal subjects.

BACKGROUND: Conventionally, ultrasonographic assessment of diaphragm contractility has involved measuring respiratory changes in diaphragm thickness (thickening fraction) using B-mode or caudal displacement with M-mode. Two-dimensional speckle-tracking has been increasingly used to assess muscle deformation ('strain') in echocardiography. We sought to determine in a pilot study if this technology could be utilized to analyze diaphragmatic contraction. METHODS: Fifty healthy adult volunteers with normal exercise capacity underwent ultrasound imaging. A linear array transducer was used for the assessment of diaphragm thickness, thickening fraction (TF), and strain in the right anterior axillary line at approximately the ninth intercostal space. A phased array transducer was applied subcostally for the assessment of diaphragm displacement on the right mid-clavicular line. Diaphragmatic images were recorded from the end of expiration through the end of inspiration at 60 % maximal inspiratory capacity. Diaphragm strain was analyzed off-line by speckle tracking imaging. Blinded inter- and intra-rater variability was tested in 10 cases. RESULTS: Mean right diaphragm thickness at end-expiration (±SD: standard deviation) was 0.24 cm (±0.1), with TF of 45.1 % (±12) at 60 % peak inspiratory effort. Mean right diaphragm caudal displacement was 4.9 cm (±1). Mean right diaphragm strain was -40.3 % (±9). A moderate correlation was seen between longitudinal strain and TF (R(2) 0.44, p < 0.0001). A weak correlation was seen between strain and caudal displacement (R(2) 0.14, p < 0.01), and an even weaker correlation was seen between caudal displacement and TF (R(2) 0.1, p = 0.04). Age, gender, and body mass index were not significantly associated with right diaphragm strain or TF. Although inter- and intra-rater variability was overall good for TF, caudal displacement, and strain (inter-rater R(2); 0.8, 0.9, and 0.7, respectively [p < 0.01], intra-rater R(2); 0.9, 0.7, and 0.9, respectively [p < 0.01]), strain values did have a slightly lower inter-rater repeatability. CONCLUSIONS: Diaphragmatic strain estimated by speckle tracking imaging was associated with conventional ultrasound measures of diaphragmatic function (TF and caudal displacement). Further clinical studies are warranted to investigate its clinical utility.

Bedside myocardial perfusion assessment with contrast echocardiography.

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency medicine 2016. Other selected articles can be found online at http://www.biomedcentral.com/collections/annualupdate2016. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Outcome prediction in sepsis: speckle tracking echocardiography based assessment of myocardial function.

INTRODUCTION: Speckle tracking echocardiography (STE) is a relatively novel and sensitive method for assessing ventricular function and may unmask myocardial dysfunction not appreciated with conventional echocardiography. The association of ventricular dysfunction and prognosis in sepsis is unclear. We sought to evaluate frequency and prognostic value of biventricular function, assessed by STE in patients with severe sepsis or septic shock. METHODS: Over an eighteen-month period, sixty patients were prospectively imaged by transthoracic echocardiography within 24 hours of meeting severe sepsis criteria. Myocardial function assessment included conventional measures and STE. Association with mortality was assessed over 12 months. RESULTS: Mortality was 33% at 30 days (n = 20) and 48% at 6 months (n = 29). 32% of patients had right ventricle (RV) dysfunction based on conventional assessment compared to 72% assessed with STE. 33% of patients had left ventricle (LV) dysfunction based on ejection fraction compared to 69% assessed with STE. RV free wall longitudinal strain was moderately associated with six-month mortality (OR 1.1, 95% confidence interval, CI, 1.02-1.26, p = 0.02, area under the curve, AUC, 0.68). No other conventional echocardiography or STE method was associated with survival. After adjustment (for example, for mechanical ventilation) severe RV free wall longitudinal strain impairment remained associated with six-month mortality. CONCLUSION: STE may unmask systolic dysfunction not seen with conventional echocardiography. RV dysfunction unmasked by STE, especially when severe, was associated with high mortality in patients with severe sepsis or septic shock. LV dysfunction was not associated with survival outcomes.

From speckle tracking echocardiography to torsion: research tool today, clinical practice tomorrow.

PURPOSE OF REVIEW: Speckle tracking is the latest available technology in echocardiography. However, the technology is still mainly used as a research tool. The potential applications of speckle tracking are many, including cardiac synchronization, regional wall motion analysis, and in the areas of cardiac mechanic studies. This review presents the background theory of speckle tracking echocardiography (STE) and how this technology can be extended to velocity vector analysis, strain, and torsion measurements. The interpretations of these measurements are covered. We also present some potential applications in the critical care setting. RECENT FINDINGS: Speckle tracking is almost always available in high-end ultrasound machines. The technology has been applied to velocity vector analysis, strain and strain rate measurements, and twist and torsion analysis. Torsion analysis and velocity vector analyses are impossible without using speckle tracking. Speckle tracking-derived strain is superior to tissue Doppler strain because it is angle-independent. A number of studies demonstrated that STE is useful in left and right heart assessments and can be used in assessing preload and afterload. SUMMARY: Speckle tracking can be used to measure instantaneous myocardial contractility, strain, and left ventricular torsion. It is still a research tool at present, but shows the promise of being a clinical tool in the future.