Sam Orde

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

Purpose of reviewSpeckle 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 findingsSpeckle 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. SummarySpeckle 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.

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.

Diagnostic workup, etiologies and management of acute right ventricle failure

IntroductionThis is a state-of-the-art article of the diagnostic process, etiologies and management of acute right ventricular (RV) failure in critically ill patients. It is based on a large review of previously published articles in the field, as well as the expertise of the authors.ResultsThe authors propose the ten key points and directions for future research in the field. RV failure (RVF) is frequent in the ICU, magnified by the frequent need for positive pressure ventilation. While no universal definition of RVF is accepted, we propose that RVF may be defined as a state in which the right ventricle is unable to meet the demands for blood flow without excessive use of the Frank–Starling mechanism (i.e. increase in stroke volume associated with increased preload). Both echocardiography and hemodynamic monitoring play a central role in the evaluation of RVF in the ICU. Management of RVF includes treatment of the causes, respiratory optimization and hemodynamic support. The administration of fluids is potentially deleterious and unlikely to lead to improvement in cardiac output in the majority of cases. Vasopressors are needed in the setting of shock to restore the systemic pressure and avoid RV ischemia; inotropic drug or inodilator therapies may also be needed. In the most severe cases, recent mechanical circulatory support devices are proposed to unload the RV and improve organ perfusionConclusionRV function evaluation is key in the critically-ill patients for hemodynamic management, as fluid optimization, vasopressor strategy and respiratory support. RV failure may be diagnosed by the association of different devices and parameters, while echocardiography is crucial.

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.

Basic critical care echocardiography: How many studies equate to competence? A pilot study using high fidelity echocardiography simulation

Background Assessment of competence in basic critical care echocardiography is complex. Competence relies on not only imaging accuracy but also interpretation and appropriate management decisions. The experience to achieve these skills, real-time, is likely more than required for imaging accuracy alone. We aimed to assess the feasibility of using simulation to assess number of studies required to attain competence in basic critical care echocardiography. Methods This is a prospective pilot study recruiting trainees at various degrees of experience in basic critical care echocardiography using experts as reference standard. We used high fidelity simulation to assess speed and accuracy using total time taken, total position difference and total angle difference across the basic acoustic windows. Interpretation and clinical application skills were assessed using a clinical scenario. ‘Cut-off’ values for number of studies required for competence were estimated. Results Twenty-seven trainees and eight experts were included. The subcostal view was achieved quickest by trainees (median 23 s, IQR 19–37). Eighty-seven percent of trainees did not achieve accuracy across all views; 81% achieved accuracy with the parasternal long axis and the least accurate was the parasternal short axis (44% of trainees). Fewer studies were required to be considered competent with imaging acquisition compared with competence in correct interpretation and integration (15 vs. 40 vs. 50, respectively). Discussion The use of echocardiography simulation to determine competence in basic critical care echocardiography is feasible. Competence in image acquisition appears to be achieved with less experience than correct interpretation and correct management decisions. Further studies are required.

Reversal in order of ventricular filling is associated with a positive fluid balance in sepsis

Dear Editor, Under normal conditions, the right ventricle (RV) fills before the left ventricle (LV) as the RV lacks a significant iso-volumetric relaxation time (IVRT) [1]. A study in heart failure patients demonstrated that a reversal in the order of ventricular filling (i.e. LV filling before RV filling) was associated with a raised pulmonary artery wedge pressure as well as increased cardiovascular events [2]. This ventricular filling reversal was a better predictor of raised left atrial pressure (LAP) than E/e′. An increased LAP may be seen in sepsis: from sepsis induced, or underlying, diastolic dysfunction or in a state of fluid overload from over-resuscitation [3]. The best current marker we have for a raised LAP is E/e′; however, this is known to have limitations in the septic cohort [4]. The objectives of our study were to assess whether reversal of RV and LV filling, as a surrogate of elevated LAP, was related to fluid balance in patients with sepsis. In addition, a potential advantage of interventricular inflow delay (IVID) is that it considers the interaction of the ventricles, rather than as separate entities. This study was a prospective, observational cohort study at the Nepean Hospital Intensive Care Unit, Sydney (14/35-LR/14/Nepean/70) with 46 septic patients (as defined by Sepsis 3 guidelines). Patients underwent a comprehensive echocardiogram study on day 3 and the onset of RV and LV filling were also recorded. The IVID was calculated as IVID = time to RV inflow − time to LV inflow time (measured from the beginning of the QRS complex). A normal IVID is negative; a positive IVID indicates a reversal in the order of filling. A positive IVID was associated with increased fluid balance (r2 = 0.17, p = 0.005) and LA volume (r2 = 0.15, p = 0.03) (see Fig. 1) and was also weakly associated with an increase in mortality (p = 0.038). The IVID also showed a positive correlation with LA volume, LV enddiastolic volume, and pulmonary artery systolic pressure (supplementary Table 1). There was no correlation between IVID and E/e′; however, there are numerous shortcomings with this parameter in the critically ill and E/e′ does not account for right ventricular dysfunction [4]. The postulated mechanism for a reversal in ventricular filling order considers an increased LAP to shorten the LV IVRT and increased pulmonary pressures causing a delay in the RV relaxation, thereby extending the RV IVRT. An increased LAP is associated with either grade II or III diastolic dysfunction and is known to be associated with mortality in the setting of sepsis [3]. In addition, it is known that a prolonged positive fluid balance is a negative prognostic factor in the outcome of sepsis [5] and can lead to raised LAP which could explain the association between a reversal in ventricular filling order and positive fluid balance. In conclusion, we found that a reversal in the order of ventricular filling (i.e. LV filling before the RV) was associated with an increased fluid balance and increased LA volumes possibly due to raised LAP. We hypothesise that

Diabetic ketoacidosis due to fulminant type 1 diabetes: A rare subtype of type 1 diabetes leading to unusual sequelae

Diabetic ketoacidosis (DKA) is a life-threatening complication of type 1 diabetes (T1D), which without treatment leads to death. Fulminant type 1 diabetes (FT1D) is a subtype characterised by a markedly rapid and almost complete destruction of pancreatic β-cells, with acute onset leading to severe metabolic derangement and commonly ICU admission. We present a case of an 18-year-old male presenting with FT1D with two rare complications of pneumomediastinum and stress-induced cardiomyopathy (SIC) with significant myocardial necrosis. We also discuss the aetiology of the pneumomediastinum; the latest thoughts on SIC: moving beyond the simple description of ‘Takotsubo cardiomyopathy’; the role of troponins in critical illness; and genetic predisposition for DKA due to FT1D.

Paradoxical septal motion: A diagnostic approach and clinical relevance

Abnormal septal motion (commonly referred to as septal bounce) is a common echocardiographic finding that occurs with several conditions, including the following: mitral stenosis, left bundle branch block, pericardial syndromes and severe pulmonary hypertension. We explore the subtle changes that occur on M‐mode imaging of the septum, other associated echocardiographic features, the impact of inspiratory effort on septal motion and relevant clinical findings. Finally, we discuss the impact of abnormal septal motion on cardiac form and function, proposing there is a clinically significant impact on biventricular filling and ejection.

Intermediate level training: A paradigm requiring reflective competence:

The role of echocardiography within the intensive care unit (ICU) has progressed dramatically in the past decade. It is now an expected part of the Intensivist’s armamentarium to diagnose and manage clinical conditions based on their ability to record and interpret ultrasound imaging. However, the acquisition of any new skill requires the responsibility to recognise the limitations of one’s knowledge, experience and expectations. We admitted a 64-year-old male to the ICU with a two-day history of vomiting, worsening renal function and hypotension. Initial transthoracic echo (TTE) was reported as showing; ventricular-septal-defect (VSD); dyskinesis of the IV septum; possible dissecting thoracic aortic aneurysm. However, on closer inspection of the parasternal long axis view, it was recognized that there was an abnormal echo-free space adjacent to the aorta (Figure 1); the Doppler jet originated from the echo-free space and not the left ventricle and occurred in diastole (Figures 2 and 3). The apical four-chamber view also demonstrated Doppler flow from the abnormal echo-free space to the right ventricle (RV) and right atrium (RA) (Figures 4 and 5). Transoesophageal echocardiogram (TOE) demonstrated the echo-free space to be pulsatile, representing a sinus of valsalva aneurysm (SOVA) originating near the right coronary cusp communicating with the RA/RV junction (Figure 6(a) and (b)). In a previous case, report of a ruptured SOVA being misdiagnosed as a VSD, it highlighted the need to demonstrate in which part of the cardiac cycle the abnormal jet is present (as above), however, the report also mentions the possibility of a coexisting VSD being masked by the ruptured SOVA, and another potential misdiagnosis being a coronary ateriovenous fistula. Our case and the case report highlight the learning-curve required when acquiring new skills, and the literature reinforces the danger of false positives (overcalling) and false-negatives (omission) as this skill is acquired . There is currently debate regarding the place for ‘intermediate level’ of training in echocardiography vs. simply ‘basic’ and ‘expert’; however, the desire for intermediate level training is not without risk. There has been discussion in the educational literature about the concept of the competency matrix (Figure 7). It states that a learner acquiring new skills begins at level of unconscious incompetence; however, this is not correct. Most learners commence a learning process knowing they do not know it. Therefore, they are consciously incompetent. It is as their skills progress and expectations of performance increase that learners are at risk of being unconsciously incompetent: they can actually regress to this level. Only with further training do they recognise this, and once again become consciously incompetent. The length of time learners spend in this stage depends on the strength of the stimulus to learn mastery. If a learner’s ceiling of desired mastery is ‘intermediate level’, then with no stimulus to achieve mastery at the ‘expert level’, the risk of ongoing unconscious incompetence is significant, leading to false-positives and false-negatives in interpretation. A practitioner who is at ‘intermediate level’ mastery needs to possess reflective competence to ensure that they recognise the constant potential of unconscious incompetence, and seek assistance when required. Our case demonstrated the requirement to utilise off-axis imaging and optimise Doppler settings. These skills require ‘expert level’ knowledge and experience. We are not arguing that ‘intermediate level’ training should be abandoned as a principle; however, it requires specific cognitive abilities of reflective competence to operate between the level of beginner and expert (Figure 7). Conscious incompetence: You become aware of how much you have to learn. You realise you require time and practice to progress. Conscious incompetence: You are starting to master the new skill, but you still have to actively think if you are doing it right. Unconscious competence: You don’t even think about your new skill anymore. The skills comes naturally as an expert. Reflective competence: The background cognitive quality that is required at all stages, that allows a

Detecting impaired myocardial relaxation in sepsis with a novel tissue Doppler parameter (septal e′/s′)

BackgroundLeft ventricular diastolic dysfunction is associated with mortality outcomes in severe sepsis and septic shock. There are ongoing issues with diagnosing diastolic dysfunction in this cohort, partly owing to the poor applicability of traditional parameters in the hyperdynamic circulation. In this feasibility study, we sought to assess the utility of a novel parameter (septal e′/s′) to identify diastolic dysfunction in patients with severe sepsis and septic shock who had normal systolic function against the 2016 American Society Echocardiography and European Association of Cardiovascular Imaging (ASE/EACI) guidelines on diastolic dysfunction.MethodsIn this prospective observational pilot study, patients identified as having severe sepsis and septic shock underwent transthoracic echocardiography on day 1 and day 3 of their intensive care unit admission. In patients with normal systolic function, septal e′/s′ was calculated using the peak modal velocity of the s′ compared with the e′ from the septal annulus tissue Doppler imaging and compared with their diastolic grade according to the 2016 ASE/EACI guidelines on diastolic dysfunction.ResultsOn day 1 of admission, 44 of 62 patients with severe sepsis and septic shock had normal systolic function. There was a strong association of those with diastolic dysfunction having a reduced septal e′/s′ compared with patients with normal diastolic function (AUC 0.91). A similar relationship was seen with patients who had indeterminate diastolic dysfunction. On day 3, 37 patients had normal systolic function. Again, there was a strong association of those with diastolic dysfunction and a reduced septal e′/s′ (AUC 0.95).ConclusionsA reduction in septal e′/s′ may indicate diastolic dysfunction in patients with severe sepsis and septic shock who have normal systolic function. As opposed to limited traditional measures of diastolic dysfunction, it is applicable in those with hyperdynamic systolic function.