What is new in critical care echocardiography?

Echocardiography Does not Reduce Mortality in Sepsis: A Re-Evaluation Using the Medical Information Mart for Intensive Care IV Dataset

OBJECTIVES

Echocardiography is commonly used for hemodynamic assessment in sepsis, but data regarding its association with outcome are conflicting. The aim of this study was to evaluate the association between echocardiography and outcomes in patients with septic shock using the Medical Information Mart for Intensive Care IV database.

DESIGN

Retrospective cohort study comparing patients who did or did not undergo transthoracic echocardiography within the first 5 days of admission for the primary outcome of 28-day mortality.

SETTING

Admissions to the Beth Israel Deaconess Medical Center intensive care from 2008 to 2019.

PATIENTS

Adults 16 years old or older with septic shock requiring vasopressor support within 48 hours of admission. Readmissions and patients admitted to the coronary care unit or cardiovascular intensive care were excluded, as well as patients with ST-elevation myocardial infarction or cardiac arrest.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Echocardiography was performed in 1,515 (27%) of 5,697 eligible admissions. The primary outcome was analyzed using a marginal structural model and rolling entry matching to adjust for baseline and time-varying confounders. Patients who underwent echocardiography showed no significant difference in 28-day mortality (adjusted hazard ratio 1.09; 95% CI, 0.95-1.25; p = 0.24). This was consistent across multiple sensitivity analyses. Secondary outcomes were changes in management instituted within 4 hours of imaging. Treatment changes occurred in 493 patients (33%) compared with 431 matched controls (29%), with the most common intervention being the administration of a fluid bolus.

CONCLUSIONS

Echocardiography in sepsis was not associated with a reduction in 28-day mortality based on observational data. These findings do not negate the utility of echo in cases of diagnostic uncertainty or inadequate response to initial treatment.

Early transthoracic echocardiography and long-term mortality in moderate- to-severe acute respiratory distress syndrome: An analysis of the Medical Information Mart for Intensive Care database

BACKGROUND

The clinical use of transthoracic echocardiography (TTE) in patients with acute respiratory distress syndrome (ARDS) in the intensive care unit (ICU) has dramatically increased, its impact on long-term prognosis in these patients has not been studied. This study aimed to explore the effect of early-TTE on long-term mortality in patients with moderate-to-severe ARDS in ICU.

METHODS

A total of 2833 patients with moderate-to-severe ARDS who had or had not received early-TTE were obtained from the Medical Information Mart for Intensive Care (MIMIC-III) database after imputing missing values by a random forest model, patients were divided into early-TTE group and non-early-TTE group according to whether they received TTE examination in ICU. A variety of statistical methods were used to balance 41 covariates and increase the reliability of this study, including propensity score matching, inverse probability of treatment weight, covariate balancing propensity score, multivariable regression, and doubly robust estimation. Chi-Square test and t-tests were used to examine the differences between groups for categorical and continuous data, respectively.

RESULTS

There was a significant improvement in 90-day mortality in the early-TTE group compared to non-early-TTE group (odds ratio  =  0.79, 95% CI: 0.64-0.98, p-value  =  0.036), revealing a beneficial effect of early-TTE. Net-input was significantly decreased in the early-TTE group on the third day of ICU admission and throughout the ICU stay, compared with non-early-TTE group (838.57 vs. 1181.89 mL, p-value  =  0.014; 4542.54 vs. 8025.25 mL, p-value  =  0.05). There was a significant difference in the reduction of serum lactate between the two groups, revealing the beneficial effect of early-TTE (0.59 vs. 0.83, p-value  =  0.009). Furthermore, the reduction in the proportion of acute kidney injury demonstrated a correlation between early-TTE and kidney protection (33% vs. 40%, p-value < 0.001).

CONCLUSIONS

Early application of TTE is beneficial to improve the long-term mortality of patients with moderate-to-severe ARDS.

Improving echographic monitoring of hemodynamics in critically ill patients: Validation of right cardiac output measurements through the modified subcostal window

OBJECTIVE

We aimed to assess the usefulness of using the right ventricle outflow tract (RVOT) velocity-time integral (VTI) for echocardiographic monitoring of cardiac output compared to the gold standard, the VTI along the left ventricle outflow tract (LVOT).

DESIGN

Prospective observational study.

SETTING

A tertiary intensive care unit.

PATIENTS

100 consecutive patients.

INTERVENTIONS

echocardiographic monitoring in critically ill patients.

MAIN VARIABLES OF INTEREST

We used intraclass correlation coefficients (ICC) to compare echocardiographic measurements of LVOT VTI through apical window with RVOT VTI through the parasternal and modified subcostal windows and to assess interobserver reproducibility. Preplanned post hoc analyses compared the ICC between ventilated and nonventilated patients.

RESULTS

At the time of echocardiography, 44 (44%) patients were mechanically ventilated and 28 (28%) were receiving vasoactive drugs. Good-quality measurements were obtained through the parasternal short-axis and/or apical views in 81 (81%) patients and in 100 (100%) patients through the subcostal window. Consistency with LVOT VTI was moderate for RVOT VTI measured from the modified subcostal view (ICC 0.727; 95%CI: 0.62-0.808) and for RVOT VTI measured from the transthoracic view (0.715; 95%CI: 0.59-0.807).

CONCLUSIONS

Measurements of RVOT VTI are moderately consistent with measurements of LVOT VTI. Adding the modified subcostal window allows monitoring RVOT VTI in all the patients of this selected cohort, even those under mechanical ventilation.

Competencies for Point-of-care Ultrasonography in ICU: An ISCCM Expert Panel Practice Recommendation

How to cite this article: Srinivasan S, Kumar PG, Govil D, Gupta S, Kumar V, Pichamuthu K, et al. Competencies for Point-of-care Ultrasonography in ICU: An ISCCM Expert Panel Practice Recommendation. Indian J Crit Care Med 2022;26(S2):S7-S12.

Competency Assessment in Focused Cardiac Ultrasound—Can the Use of Sequential Testing Help Tailor Training Requirements?

Varying numbers of scans are required by different professional bodies before focused cardiac ultrasound (FCU) competence is assumed. It has been suggested that innovation in the assessment of FCU competence is needed and that competency assessment needs to be more individualized. We report our experience of how the use of sequential testing may help personalize the assessment of FCU competence.

The diagnostic yield of transthoracic echocardiography in the intensive care unit: A retrospective observational analysis

BACKGROUND

Transthoracic echocardiography (TTE) is a commonly requested ICU investigation. Despite this, limited data exist regarding the diagnostic yield of unselected TTEs in a heterogenous ICU population.

METHODS

A retrospective, cross-sectional, single-center study was performed. All ICU patients admitted from January 2018 to February 2019 were included.

AIMS

The primary aim was to define the indications for, and diagnostic yield of, TTEs performed in the ICU. We also investigated the association between major abnormalities identified on TTE and mortality.

RESULTS

There were 358 patients admitted to the ICU during the study period. Of these patients, 115 (32%) had a TTE performed during their ICU stay. The primary indication was to assess left ventricular function. Just under two-thirds of TTEs (65%) were normal or had minor abnormalities. Compared to the rest of the ICU population in our study (including both patients without a TTE performed and patients with a normal TTE), patients with an abnormal TTE had higher ICU (35.9% vs 21.3%, Odds Ratio [OR], 2.06; 95% CI, 1.02-4.19, P = .04) and in-hospital (43.6% vs 30.3%, OR, 2.64; 95% CI, 1.33-5.25, P = .01) mortality.

CONCLUSIONS

A formal TTE was performed in one-third of patients during their ICU admission. Major abnormalities were identified in over one-third of these TTEs. ICU and in-hospital mortality were higher in patients with an abnormal TTE.

Continuous cardiac output assessment or serial echocardiography during septic shock resuscitation?

Septic shock is the leading cause of cardiovascular failure in the intensive care unit (ICU). Cardiac output is a primary component of global oxygen delivery to organs and a sensitive parameter of cardiovascular failure. Any mismatch between oxygen delivery and rapidly varying metabolic demand may result in tissue dysoxia, hence organ dysfunction. Since the intricate alterations of both vascular and cardiac function may rapidly and widely change over time, cardiac output should be measured repeatedly to characterize the type of shock, select the appropriate therapeutic intervention, and evaluate patient's response to therapy. Among the numerous techniques commercially available for measuring cardiac output, transpulmonary thermodilution (TPT) provides a continuous monitoring with external calibration capability, whereas critical care echocardiography (CCE) offers serial hemodynamic assessments. CCE allows early identification of potential sources of inaccuracy of TPT, including right ventricular failure, severe tricuspid or left-sided regurgitations, intracardiac shunt, very low flow states, or dynamic left ventricular outflow tract obstruction. In addition, CCE has the unique advantage of depicting the distinct components generating left ventricular stroke volume (large cavity size vs. preserved contractility), providing information on left ventricular diastolic properties and filling pressures, and assessing pulmonary artery pressure. Since inotropes may have deleterious effects if misused, their initiation should be based on the documentation of a cardiac dysfunction at the origin of the low flow state by CCE. Experts widely advocate using CCE as a first-line modality to initially evaluate the hemodynamic profile associated with shock, as opposed to more invasive techniques. Repeated assessments of both the efficacy (amplitude of the positive response) and tolerance (absence of side-effect) of therapeutic interventions are required to best guide patient management. Overall, TPT allowing continuous tracking of cardiac output variations and CCE appear complementary rather than mutually exclusive in patients with septic shock who require advanced hemodynamic monitoring.

Emergency bedside ultrasound-benefits as well as caution: Part 2: Echocardiography

PURPOSE OF REVIEW

Critical care echocardiography (CCE) has become an important component of general critical care ultrasonography, and a current review of its performance is presented.

RECENT FINDINGS

Basic CCE should be performed as a goal-directed examination to better identify specific signs and to answer important clinical questions concerning acute hemodynamic concerns. It has evolved in the ICU and also in the emergency department not only for improved diagnostic capability but also as an effective part of the triage process. It remains an efficacious procedure even in patients with respiratory failure when combined with lung ultrasonography. Numerous acronyms were proposed, but in all cases, CCE responds to the same rules as fundamental echocardiography. Basic CCE requires accessible and comprehensive training for physicians and is mandatory for all intensivists. Development of pocket echo devices may increase the use of basic CCE as has miniaturization of other medical technologies. Performance should be managed by guidelines, and the CCE training program should be standardized worldwide. More trials are welcome to evaluate its impact on patient outcomes.

SUMMARY

Thanks to its ability to quickly obtain a diagnostic orientation at the bedside and to implement targeted therapy, basic CCE over the past decade has become an essential tool for hemodynamic assessment of the cardiopulmonary unstable patient. Its more recent incorporation into the education of trainees in medical school and residencies/fellowships has reinforced its perceived importance in critical care management, despite the relative paucity as yet of rigorous scientific evidence demonstrating positive outcome modification from its use.

Comparison of echocardiographic and invasive measures of volaemia and cardiac performance in critically ill patients

Echocardiographic measurements are used in critical care to evaluate volume status and cardiac performance. Mean systemic filling pressure and global heart efficiency measures intravascular volume and global heart function. This prospective study conducted in fifty haemodynamically stabilized, mechanically ventilated patients investigated relationships between static echocardiographic variables and estimates of global heart efficiency and mean systemic filling pressure. Results of univariate analysis demonstrated weak correlations between left ventricular end-diastolic volume index (r = 0.27, p = 0.04), right atrial volume index (rho = 0.31, p = 0.03) and analogue mean systemic filling pressure; moderate correlations between left ventricular ejection fraction (r = 0.31, p = 0.03), left ventricular global longitudinal strain (r = 0.36, p = 0.04), tricuspid annular plane systolic excursion (rho = 0.37, p = 0.01) and global heart efficiency. No significant correlations were demonstrated by multiple regression. Mean systemic filling pressure calculated with cardiac output measured by echocardiography demonstrated good agreement and correlation with invasive techniques (bias 0.52 ± 1.7 mmHg, limits of agreement -2.9 to 3.9 mmHg, r = 0.9, p < 0.001). Static echocardiographic variables did not reliably reflect the volume state as defined by estimates of mean systemic filling pressure. The agreement between static echocardiographic variables of cardiac performance and global heart efficiency lacked robustness. Echocardiographic measurements of cardiac output can be reliably used in calculation of mean systemic filling pressure.

Levels of training in critical care echocardiography in adults. Recommendations from the College of Intensive Care Medicine Ultrasound Special Interest Group

Critical care echocardiography (CCE) is commonly performed in many intensive care units across Australia and New Zealand (ANZ). The scope of practice ranges from Basic CCE through to Advanced CCE and includes the use of transthoracic echocardiography and transoesophageal echocardiography. Many training and qualification pathways exist with no standardisation of education goals. This document defines different levels of CCE expertise and recommends minimum training standards for each level of adult CCE in ANZ. Guidelines committee of College of Intensive Care Medicine's Ultrasound Special Interest Group held multiple face to face meetings, organised teleconferences, conducted a survey of the Fellows of the college and reviewed the international CCE training pathways prior to writing these guidelines.

Cardiovascular failure and weaning

Cardiac patients are at high risk of weaning failure due to the abrupt burden to the cardiovascular system resulting from the transition from positive-pressure ventilation to spontaneous breathing. Similarly, numerous patients with borderline cardiac function, left ventricular diastolic dysfunction, chronic obstructive pulmonary disease, especially with associated fluid overload or cumulative positive fluid balance, are at high risk of weaning failure of cardiac origin. The diagnosis of weaning-induced pulmonary oedema (WiPO) relies on the measurement of elevated left ventricular filling pressure, or on the presence of a surrogate reflecting pulmonary or cardiac congestion. Plasma concentration of B-type natriuretic peptide and N-terminal proBNP, biological signs of hemoconcentration (increased circulating protein or hemoglobin levels), or measurement of extravascular pulmonary lung water using transpulmonary thermodilution have been proved valuable surrogates for the identification of weaning failure. Nevertheless, studies have not yet compared these indirect methods to precisely determine their respective diagnostic values for the identification of WiPO, especially in heart failure patients. In addition, none of these approaches directly assess left ventricular filling pressure and the mechanism of WiPO. In contrast, critical care echocardiography is ideally suited to establish the diagnosis of weaning failure of cardiac origin. It allows identifying the high-risk population, monitoring hemodynamically the patient at risk, depicting an abrupt increase of left ventricular filling pressure consistent with WiPO when the patient fails weaning, identifying the underlying mechanism of WiPO, and finally it allows tailoring the therapeutic management of the patient who failed weaning. The impact on patient-centered outcomes of such integrated management strategy based on critical care echocardiography deserves to be prospectively tested in a large population of patients at high risk of weaning failure of cardiac origin.