A decade of progress in critical care echocardiography: a narrative review

Machine learning for the real-time assessment of left ventricular ejection fraction in critically ill patients: a bedside evaluation by novices and experts in echocardiography

BACKGROUND

Machine learning algorithms have recently been developed to enable the automatic and real-time echocardiographic assessment of left ventricular ejection fraction (LVEF) and have not been evaluated in critically ill patients.

METHODS

Real-time LVEF was prospectively measured in 95 ICU patients with a machine learning algorithm installed on a cart-based ultrasound system. Real-time measurements taken by novices (LVEF_Nov) and by experts (LVEF_Exp) were compared with LVEF reference measurements (LVEF_Ref) taken manually by echo experts.

RESULTS

LVEF_Ref ranged from 26 to 80% (mean 54 ± 12%), and the reproducibility of measurements was 9 ± 6%. Thirty patients (32%) had a LVEF_Ref < 50% (left ventricular systolic dysfunction). Real-time LVEF_Exp and LVEF_Nov measurements ranged from 31 to 68% (mean 54 ± 10%) and from 28 to 70% (mean 54 ± 9%), respectively. The reproducibility of measurements was comparable for LVEF_Exp (5 ± 4%) and for LVEF_Nov (6 ± 5%) and significantly better than for reference measurements (p < 0.001). We observed a strong relationship between LVEF_Ref and both real-time LVEF_Exp (r = 0.86, p < 0.001) and LVEF_Nov (r = 0.81, p < 0.001). The average difference (bias) between real time and reference measurements was 0 ± 6% for LVEF_Exp and 0 ± 7% for LVEF_Nov. The sensitivity to detect systolic dysfunction was 70% for real-time LVEF_Exp and 73% for LVEF_Nov. The specificity to detect systolic dysfunction was 98% both for LVEF_Exp and LVEF_Nov.

CONCLUSION

Machine learning-enabled real-time measurements of LVEF were strongly correlated with manual measurements obtained by experts. The accuracy of real-time LVEF measurements was excellent, and the precision was fair. The reproducibility of LVEF measurements was better with the machine learning system. The specificity to detect left ventricular dysfunction was excellent both for experts and for novices, whereas the sensitivity could be improved.

TRIAL REGISTRATION

NCT05336448. Retrospectively registered on April 19, 2022.

Effects of technology-based educational tools on nursing learning outcomes in intensive care units: a systematic review and meta-analysis

BACKGROUND

Nurses working in the Intensive Care Unit (ICU), due to the sensitivity and difficulty of tasks, need continuous and scientific training to be able to offer the best performance in difficult situations and use their knowledge in the best way. Also, nursing students spend internships in ICUs and receive special training in practice in the actual center. Educational tools based on new technologies can potentially improve the educational outcomes of nursing in ICUs.

OBJECTIVES

 The present study aims to review and evaluate the effect of using technology-based educational tools for training critical care nurses and nursing students.

METHODS

 A comprehensive search was conducted to identify peer-reviewed English language articles in Embase, Medline (through PubMed), Scopus, and ISI web of science published from 2010 to Feb 18, 2022. The studies that examined the effectiveness of technology-based educational interventions with control groups were included. The risk of bias in each study was assessed using the Cochrane Collaboration's tool. Also, we used Standard Mean Difference (SMD) to estimate the effect of technology-based educational tools on learning outcomes. All meta-analyses were performed with a random effects model in Stata Ver.16.

RESULTS

 Altogether, ten studies were eligible for the quality assessment and systematic review, while one study that had not reported the pre-intervention analysis was excluded from the meta-analysis. Nine studies were considered to have a low RoB regarding reporting ways, and one of them showed a high risk. Performance and selection bias caused a high risk in six and five of the studies, respectively. In the meta-analysis, improvement in knowledge (SMD = 0.91), skills (SMD = 0.52), and self-confidence (SMD = 0.96) was noticed by applying technology-based educational tools.

CONCLUSION

It can be offered that if the learning method based on the new technologies tested is more effective than conventional teaching methods, they are likely to improve the learning outcome significantly. The new-developed tools also have great potential in improving health care functions among nurses or nursing students as well as enhancing the quality of life and patient satisfaction.

Feasibility and discriminatory value of tissue motion annular displacement in sepsis-induced cardiomyopathy: a single-center retrospective observational study

Background

There is no formal diagnostic criterion for sepsis-induced cardiomyopathy (SICM), but left ventricular ejection fraction (LVEF) < 50% was the most commonly used standard. Tissue motion annular displacement (TMAD) is a novel speckle tracking indicator to quickly assess LV longitudinal systolic function. This study aimed to evaluate the feasibility and discriminatory value of TMAD for predicting SICM, as well as prognostic value of TMAD for mortality.

Methods

We conducted a single-center retrospective observational study in patients with sepsis or septic shock who underwent echocardiography examination within the first 24 h after admission. Basic clinical information and conventional echocardiographic data, including mitral annular plane systolic excursion (MAPSE), were collected. Based on speckle tracking echocardiography (STE), global longitudinal strain (GLS) and TMAD were, respectively, performed offline. The parameters acquisition rate, inter- and intra-observer reliability, time consumed for measurement were assessed for the feasibility analysis. Areas under the receiver operating characteristic curves (AUROC) values were calculated to assess the discriminatory value of TMAD/GLS/MAPSE for predicting SICM, defined as LVEF < 50%. Kaplan–Meier survival curve analysis was performed according to the cutoff values in predicting SICM. Cox proportional hazards model was performed to determine the risk factors for 28d and in-hospital mortality.

Results

A total of 143 patients were enrolled in this study. Compared with LVEF, GLS or MAPSE, TMAD exhibited the highest parameter acquisition rate, intra- and inter-observer reliability. The mean time for offline analyses with TMAD was significantly shorter than that with LVEF or GLS (p < 0.05). According to the AUROC analysis, TMADMid presented an excellent discriminatory value for predicting SICM (AUROC > 0.9). Patients with lower TMADMid (< 9.75 mm) had significantly higher 28d and in-hospital mortality (both p < 0.05). The multivariate Cox proportional hazards model revealed that BMI and SOFA were the independent risk factors for 28d and in-hospital mortality in sepsis cases, but TMAD was not.

Conclusion

STE-based TMAD is a novel and feasible technology with promising discriminatory value for predicting SICM with LVEF < 50%.

Full and simplified assessment of left ventricular diastolic function in covid-19 patients admitted to ICU: Feasibility, incidence, and association with mortality

PURPOSE

Left ventricular diastolic dysfunction (LVDD) is associated with poor outcomes in the intensive care unit (ICU). Nonetheless, precise reporting of LVDD in COVID-19 patients is currently lacking and assessment could be challenging.

METHODS

We performed an echocardiography study in COVID-19 patients admitted to ICU with the aim to describe the feasibility of full or simplified LVDD assessment and its incidence. We also evaluated the association of LVDD or of single echocardiographic parameters with hospital mortality.

RESULTS

Between 06.10.2020 and 18.02.2021, full diastolic assessment was feasible in 74% (n = 26/35) of patients receiving a full echocardiogram study. LVDD incidence was 46% (n = 12/26), while the simplified assessment produced different results (incidence 81%, n = 21/26). Nine patients with normal function on full assessment had LVDD with simplified criteria (grade I = 2; grade II = 3; grade III = 4). Nine patients were hospital-survivors (39%); the incidence of LVDD (full assessment) was not different between survivors (n = 2/9, 22%) and non-survivors (n = 10/17, 59%; p = .11). The E/e' ratio lateral was lower in survivors (7.4 [3.6] vs. non-survivors 10.5 [6.3], p = .03). We also found that s' wave was higher in survivors (average, p = .01).

CONCLUSION

In a small single-center study, assessment of LVDD according to the latest guidelines was feasible in three quarters of COVID-19 patients. Non-survivors showed a trend toward greater LVDD incidence; moreover, they had significantly worse s' values (all) and higher E/e' ratio (lateral).

The Role of Left Ventricular Ejection Fraction and Left Ventricular Outflow Tract Velocity-Time Integral in Assessing Cardiovascular Impairment in Septic Shock

Background: the role of echocardiography in septic shock remains controversial, since depressed cardiac afterload may overestimate left ventricular (LV) systolic performance and mask septic cardiomyopathy (SC). We hypothesized that afterload-adjusted LV ejection fraction (LVEF) and LV outflow tract velocity-time integral (VTI) values for given systemic vascular resistances (SVR) could provide novel insights into recognizing and stratifying the severity of SC. Methods: in this observational, monocentric study, we prospectively included 14 mechanically-ventilated patients under septic-shock who all had a Pulse index Continuous Cardiac Output (PiCCO) system in place for hemodynamic monitoring. Echocardiographic and PiCCO longitudinal examinations (71 measurements overall) were performed simultaneously at the onset of septic shock and every 12 h for 60 h overall. Results: VTI-derived stroke volume (SV) and cardiac output (CO) were significantly correlated with PiCCO measurements (r ≥ 0.993, both p < 0.001). LVEF and VTI showed linear and exponential inverse correlation to SVR (R2 = 0.183 vs. 0.507 and p < 0.001 vs. p < 0.001, respectively). The equations LVEF = 86.168 − 0.011 × SVR and VTI = 41.23 × e(−0.0005×SVR) were found to provide “predicted” values for given SVR. Measured to predicted LVEF ratios (for given SVR), the afterload-adjusted LVEF defined the severity of SC (mild ≥ 90%, 80% ≤ moderate < 90% and severe < 80%). Mild SC demonstrated normal/supra-normal LVEF, normal VTI and SVR. Moderate SC showed lower LVEF and SVR, yet increased LV end-diastolic volume (LVEDV), VTI, SV and CO compared with mild SC (all p < 0.05). Severe SC was distinguished from moderate SC by markedly reduced LVEF, LVEDV, VTI, SV, CO and significantly increased SVR (all p < 0.05). LVEF and VTI decreased over time in mild SC, LVEF decreased in moderate SC, and LVEF and VTI increased over time in severe SC (p ≤ 0.038). LVEF and VTI demonstrated significant performance in identifying severe SC [cut-off < 61.5%, area under the curve (AUC) = 1 ± 0.0, sensitivity/specificity = 100/100, p < 0.001 vs. cut-off < 17.9 cm, AUC = 0.882 ± 0.042, sensitivity/specificity = 80/77, p < 0.001, respectively]. VTI but not LVEF demonstrated significant diagnostic performance in identifying both SVR < 800 dynes·s·cm−5 and SVR > 1500 dynes·s·cm−5 (cut-off > 24.46 cm, AUC = 0.889 ± 0.049, sensitivity/specificity = 75/100, p < 0.001; cut-off < 16.8, AUC = 0.0.857 ± 0.082, sensitivity/specificity = 83/86, p = 0.002, respectively).Conclusions: our study suggests that ICU bedside echocardiographic assessment of LVEF, VTI and their adjusted to corresponding SVR values provides valuable insights for the comprehension of SC phenotypes, underlying vasoplegia and cardiac output fluctuations in septic shock.

Right ventricular strain measurements in critically ill patients: an observational SICS sub-study

BACKGROUND

Right ventricular (RV) dysfunction is common in critically ill patients and is associated with poor outcomes. RV function is usually evaluated by Tricuspid Annular Plane Systolic Excursion (TAPSE) which can be obtained using critical care echocardiography (CCE). Myocardial deformation imaging, measuring strain, is suitable for advanced RV function assessment and has widely been studied in cardiology. However, it is relatively new for the Intensive Care Unit (ICU) and little is known about RV strain in critically ill patients. Therefore, the objectives of this study were to evaluate the feasibility of RV strain in critically ill patients using tissue-Doppler imaging (TDI) and explore the association between RV strain and conventional CCE measurements representing RV function.

METHODS

This is a single-center sub-study of two prospective observational cohorts (Simple Intensive Care Studies (SICS)-I and SICS-II). All acutely admitted adults with an expected ICU stay over 24 h were included. CCE was performed within 24 h of ICU admission. In patients in which CCE was performed, TAPSE, peak systolic velocity at the tricuspid annulus (RV s') and TDI images were obtained. RV free wall longitudinal strain (RVFWSL) and RV global four-chamber longitudinal strain (RV4CSL) were measured during offline analysis.

RESULTS

A total of 171 patients were included. Feasibility of RVFWSL and RV4CSL was, respectively, 62% and 56% in our population; however, when measurements were performed, intra- and inter-rater reliability based on the intraclass correlation coefficient were good to excellent. RV dysfunction based on TAPSE or RV s' was found in 56 patients (33%) and 24 patients (14%) had RV dysfunction based on RVFWSL or RV4CSL. In 14 patients (8%), RVFWSL, RV4CSL, or both were reduced, despite conventional RV function measurements being preserved. These patients had significantly higher severity of illness scores. Sensitivity analysis with fractional area change showed similar results.

CONCLUSIONS

TDI RV strain imaging in critically ill patients is challenging; however, good-to-excellent reproducibility was shown when measurements were adequately obtained. Future studies are needed to elucidate the diagnostic and prognostic value of RV strain in critically ill patients, especially to outweigh the difficulty and effort of imaging against the clinical value.

The emerging concept of fluid tolerance: A position paper

Fluid resuscitation is a core component of emergency and critical care medicine. While the focus of clinicians has largely been on detecting patients who would respond to fluid therapy, relatively little work has been done on assessing patients' tolerance to this therapy. In this article we seek to review the concept of fluid tolerance, propose a working definition, and introduce relevant clinical signals by which physicians can assess fluid tolerance, hopefully becoming a starting point for further research.

Point of care maternal ultrasound in obstetrics

Ultrasound is the hallmark imaging modality traditionally used by obstetricians for fetal diagnosis and surveillance. The COVID-19 pandemic highlighted the role of point of care ultrasound for expeditious assessment of the maternal cardiopulmonary status. The familiarity of obstetricians with ultrasound, coupled with the availability of ultrasound equipment without the need to transport the patient, make point of care ultrasound particularly valuable in the labor and delivery unit. The rising contribution of cardiopulmonary disorders to maternal morbidity and mortality carves out many potential applications for point of care ultrasound during labor and delivery. Obstetricians have access to the technology and the skills to obtain the basic views required to assess for the presence of pulmonary edema, ventricular dysfunction, or intra-abdominal free fluid. Point of care ultrasound can be used routinely for the evaluation of pulmonary complaints or in the assessment of hypotension and may play an essential role in the diagnosis and management of life-threatening emergencies such as shock, an amniotic fluid embolism, or cardiac arrest. We reviewed the currently established point of care ultrasound protocols for the evaluation of cardiopulmonary complaints through the lens of the obstetrician. We call on educators and academic leaders to incorporate maternal point of care ultrasound teachings into existing curricula. Point of care ultrasound is of enormous value for providers with limited access to diagnostic imaging or subspecialty providers. With the growing complexity of the obstetrical population, acquiring the clinical skills to meet these evolving needs is a requisite step in the ongoing efforts to reduce maternal morbidity and mortality.

Heart Failure Due to Liver Involvement of Hereditary Hemorrhagic Telangiectasia, Diagnosed by Point-of-Care Ultrasonography

Osler-Weber-Rendu syndrome, also known as hereditary hemorrhagic telangiectasia (HHT), is a rare inherited disorder characterized by the presence of systemic arteriovenous malformations, which most commonly affects the liver. One of the most serious complications of liver compromise is high output heart failure (HOHF). In this case study, point-of-care ultrasonography is utilized as a means to describe the diagnostic findings of an intensive care unit patient diagnosed with liver involvement of HHT and the development of HOHF.

Association between Wait Time for Transthoracic Echocardiography and 28-Day Mortality in Patients with Septic Shock: A Cohort Study

Background: the optimal timing of Transthoracic echocardiography (TTE) performance for patients with septic shock remains unexplored. Methods: a retrospective cohort study included patients with septic shock in the MIMIC-Ⅲ database. Risk-adjusted restricted cubic splines modeled the 28-day mortality according to time elapsed from ICU admission to receive TTE. The cut point when a smooth curve inflected was selected to define early and delayed group. We applied propensity score matching (PSM) to ensure our findings were reliable. Causal mediation analysis was used to assess the intermediate effect of fluid balance within 72 h after ICU admission. Results: 3264 participants were enrolled and the risk of 28-day mortality increased until the wait time was around 10 h (Early group) and then was relatively flat afterwards (Delayed group). A beneficial effect of early TTE in terms of the 28-day mortality was observed (HRs 0.73−0.78, all p < 0.05) in the PSM. The indirect effect brought by the fluid balance on day 2 and 3 was significant (both p = 0.006). Conclusion: early TTE performance might be associated with lower risk-adjusted 28-day mortality in patients with septic shock. Better fluid balance may have mediated this effect. A wait time within 10 h after ICU may represent a threshold defining progressively increasing risk.

Risk factors of postoperative septic cardiomyopathy in perioperative sepsis patients

Objective

This study aimed to clarify the relevant risk factors of septic cardiomyopathy (SCM) in perioperative sepsis patients.

Methods

This retrospective study evaluated patients who were diagnosed with sepsis during the perioperative period and postoperatively admitted to the intensive care unit (ICU) in the Second Affiliated Hospital of Soochow University, the First Affiliated Hospital of Soochow University, and the Suzhou Municipal Hospital between January 2017 and November 2020. They were divided into two groups as the septic cardiomyopathy group (SCM group) and the non-SCM group (NSCM group). Factors with P < 0.1 were compared between groups and were analyzed by multivariate logistic regression to screen the risk factors of sepsis cardiomyopathy. The area under the receiver operating characteristic (ROC) curve was used to verify the discriminative ability of multivariate logistic regression results. Hosmer-Lemeshow goodness of fit test was used to verify the calibration ability of multiple logistic regression results.

Result

Among the 269 patients, 49 patients had SCM. Sequential Organ Failure Assessment (SOFA) score (adjusted odds ratio [AOR] = 2.535, 95% confidence interval (CI): 1.186-1.821, P = 0.000]) and endoscopic surgery (AOR = 3.154, 95% CI: 1.173-8.477, P = 0.023]) were identified to be independent risk factors for SCM. Patients with a SOFA score ≥ 7 had a 46.831-fold higher risk of SCM (AOR =46.831, 95% CI: 10.511-208.662, P < 0.05). The multivariate logistic regression results had good discriminative (area under the curve: 0.902 [95% CI: 0.852-0.953]) and calibration (c² = 4.401, P = 0.819) capabilities. The predictive accuracy was 86.2%. The rates of mechanical ventilation and tracheotomy were significantly higher in the SCM group than in the NSCM group (both P < 0.05). The SCM group also had a significantly longer duration of mechanical ventilation (P < 0.05) and significantly higher rates of continuous renal replacement therapy (CRRT) and CRRT-related mortality (P < 0.05). Further, the total length of stay and hospitalization cost were significantly higher in the SCM group than in the NSCM group (P < 0.05).

Conclusion

Endoscopic surgery and SOFA score ≥ 7 during postoperative ICU admission were independent risk factors for SCM within 48 hours postoperatively in patients with perioperative sepsis.

Cardiac output monitoring - invasive and noninvasive

PURPOSE OF REVIEW

The purpose of this article is to review various contemporary cardiac output (CO) measurement technologies available and their utility in critically ill patients.

RECENT FINDINGS

CO measurement devices can be invasive, minimally invasive, or noninvasive depending upon their method of CO measurement. All devices have pros and cons, with pulmonary artery catheter (PAC) being the gold standard. The invasive techniques are more accurate; however, their invasiveness can cause more complications. The noninvasive devices predict CO via mathematical modeling with several assumptions and are thus prone to errors in clinical situations. Recently, PAC has made a comeback into clinical practice especially in cardiac intensive care units (ICUs). Critical care echocardiography (CCE) is an upcoming tool that not only provides CO but also helps in differential diagnosis. Lack of proper training and nonavailability of equipment are the main hindrances to the wide adoption of CCE.

SUMMARY

PAC thermodilution for CO measurement is still gold standard and most suitable in patients with cardiac pathology and with experienced user. CCE offers an alternative to thermodilution and is suitable for all ICUs; however, structural training is required.

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.

Visual Rounds Based on Multiorgan Point-of-Care Ultrasound in the ICU

Point-of-care ultrasonography (POCUS) is performed by a treating clinician at the patient's bedside, provides a acquisition, interpretation, and immediate clinical integration based on ultrasonographic imaging. The use of POCUS is not limited to one specialty, protocol, or organ system. POCUS provides the treating clinician with real-time diagnostic and monitoring information. Visual rounds based on multiorgan POCUS act as an initiative to improve clinical practice in the Intensive Care Unit and are urgently needed as part of routine clinical practice.

Hyperdynamic Left Ventricular Ejection Fraction in ICU Patients With Sepsis

OBJECTIVES

To evaluate the cause and prognosis of hyperdynamic left ventricular ejection fraction in critically ill patients with sepsis.

DESIGN

Retrospective, single-center cohort study.

SETTING

University Hospital ICU, Birmingham, United Kingdom.

PATIENTS

ICU patients who received a transthoracic echocardiogram within 7 days of sepsis between April 2016 and December 2019.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The 90-day mortality rates of normal (55-70%), depressed (< 55%), and hyperdynamic left ventricular ejection fraction (> 70%) were compared. Multivariate logistic regression analysis was performed to determine the association of left ventricular ejection fraction phenotypes with mortality and the association of clinical variables with left ventricular ejection fraction phenotypes. One thousand fourteen patients met inclusion criteria and were 62 years old (interquartile range, 47-72), with mostly respiratory infections (n = 557; 54.9%). Ninety-day mortality was 32.1% (n = 325). Patients with hyperdynamic left ventricular ejection fraction had a higher mortality than depressed and normal left ventricular ejection fraction cohorts (58.9% [n = 103] vs 34.0% [n = 55] vs 24.7% [n = 167]; p < 0.0001, respectively). After multivariate logistic regression, hyperdynamic left ventricular ejection fraction was independently associated with mortality (odds ratio, 3.90 [2.09-7.40]), whereas depressed left ventricular ejection fraction did not (odds ratio, 0.62 [0.28-1.37]). Systemic vascular resistance was inversely associated with hyperdynamic left ventricular ejection fraction (odds ratio, 0.79 [0.58-0.95]), and age, frailty, and ischemic heart disease were associated with depressed left ventricular ejection fraction.

CONCLUSIONS

Hyperdynamic left ventricular ejection fraction was associated with mortality in septic ICU patients and may reflect unmitigated vasoplegia from sepsis. Depressed left ventricular ejection fraction was not associated with mortality but was associated with cardiovascular disease.

Contemporary Review of Hemodynamic Monitoring in the Critical Care Setting

Hemodynamic assessment remains the most valuable adjunct to physical examination and laboratory assessment in the diagnosis and management of shock. Through the years, multiple modalities to measure and trend hemodynamic indices have evolved with varying degrees of invasiveness. Pulmonary artery catheter (PAC) has long been considered the gold standard of hemodynamic assessment in critically ill patients and in recent years has been shown to improve clinical outcomes among patients in cardiogenic shock. The invasive nature of PAC is often cited as its major limitation and has encouraged development of less invasive technologies. In this review, the authors summarize the literature on the mechanism and validation of several minimally invasive and noninvasive modalities available in the contemporary intensive care unit. They also provide an update on the use of focused bedside echocardiography.

The effects of positive end-expiratory pressure on cardiac function: a comparative echocardiography-conductance catheter study

Background

Echocardiographic parameters of diastolic function depend on cardiac loading conditions, which are altered by positive pressure ventilation. The direct effects of positive end-expiratory pressure (PEEP) on cardiac diastolic function are unknown.

Methods

Twenty-five patients without apparent diastolic dysfunction undergoing coronary angiography were ventilated noninvasively at PEEPs of 0, 5, and 10 cmH₂O (in randomized order). Echocardiographic diastolic assessment and pressure–volume-loop analysis from conductance catheters were compared. The time constant for pressure decay (τ) was modeled with exponential decay. End-diastolic and end-systolic pressure volume relationships (EDPVRs and ESPVRs, respectively) from temporary caval occlusion were analyzed with generalized linear mixed-effects and linear mixed models. Transmural pressures were calculated using esophageal balloons.

Results

τ values for intracavitary cardiac pressure increased with the PEEP (n = 25; no PEEP, 44 ± 5 ms; 5 cmH₂O PEEP, 46 ± 6 ms; 10 cmH₂O PEEP, 45 ± 6 ms; p < 0.001). This increase disappeared when corrected for transmural pressure and diastole length. The transmural EDPVR was unaffected by PEEP. The ESPVR increased slightly with PEEP. Echocardiographic mitral inflow parameters and tissue Doppler values decreased with PEEP [peak E wave (n = 25): no PEEP, 0.76 ± 0.13 m/s; 5 cmH₂O PEEP, 0.74 ± 0.14 m/s; 10 cmH₂O PEEP, 0.68 ± 0.13 m/s; p = 0.016; peak A wave (n = 24): no PEEP, 0.74 ± 0.12 m/s; 5 cmH₂O PEEP, 0.7 ± 0.11 m/s; 10 cmH₂O PEEP, 0.67 ± 0.15 m/s; p = 0.014; E’ septal (n = 24): no PEEP, 0.085 ± 0.016 m/s; 5 cmH₂O PEEP, 0.08 ± 0.013 m/s; 10 cmH₂O PEEP, 0.075 ± 0.012 m/s; p = 0.002].

Conclusions

PEEP does not affect active diastolic relaxation or passive ventricular filling properties. Dynamic echocardiographic filling parameters may reflect changing loading conditions rather than intrinsic diastolic function. PEEP may have slight positive inotropic effects.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT02267291, registered 17. October 2014.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-022-02014-1.

Machine learning algorithm using publicly available echo database for simplified “visual estimation” of left ventricular ejection fraction

BACKGROUND

Left ventricular ejection fraction calculation automation typically requires complex algorithms and is dependent of optimal visualization and tracing of endocardial borders. This significantly limits usability in bedside clinical applications, where ultrasound automation is needed most.

AIM

To create a simple deep learning (DL) regression-type algorithm to visually estimate left ventricular (LV) ejection fraction (EF) from a public database of actual patient echo examinations and compare results to echocardiography laboratory EF calculations.

METHODS

A simple DL architecture previously proven to perform well on ultrasound image analysis, VGG16, was utilized as a base architecture running within a long short term memory algorithm for sequential image (video) analysis. After obtaining permission to use the Stanford EchoNet-Dynamic database, researchers randomly removed approximately 15% of the approximately 10036 echo apical 4-chamber videos for later performance testing. All database echo examinations were read as part of comprehensive echocardiography study performance and were coupled with EF, end systolic and diastolic volumes, key frames and coordinates for LV endocardial tracing in csv file. To better reflect point-of-care ultrasound (POCUS) clinical settings and time pressure, the algorithm was trained on echo video correlated with calculated ejection fraction without incorporating additional volume, measurement and coordinate data. Seventy percent of the original data was used for algorithm training and 15% for validation during training. The previously randomly separated 15% (1263 echo videos) was used for algorithm performance testing after training completion. Given the inherent variability of echo EF measurement and field standards for evaluating algorithm accuracy, mean absolute error (MAE) and root mean square error (RMSE) calculations were made on algorithm EF results compared to Echo Lab calculated EF. Bland-Atlman calculation was also performed. MAE for skilled echocardiographers has been established to range from 4% to 5%.

RESULTS

The DL algorithm visually estimated EF had a MAE of 8.08% (95%CI 7.60 to 8.55) suggesting good performance compared to highly skill humans. The RMSE was 11.98 and correlation of 0.348.

CONCLUSION

This experimental simplified DL algorithm showed promise and proved reasonably accurate at visually estimating LV EF from short real time echo video clips. Less burdensome than complex DL approaches used for EF calculation, such an approach may be more optimal for POCUS settings once improved upon by future research and development.

Nursing management of the critical thinking and care quality of ICU nurses: A cross-sectional study

AIM

To explore the effectiveness of a digital learning management system in enhancing intensive care unit nurses' critical care knowledge and critical thinking tendency.

BACKGROUND

Learning intensive care unit knowledge and skills is essential for the continuing education of nurses, and impacts patient health outcomes. Enhancing intensive care unit nurses' critical care abilities is a medical care quality concern in clinical practice.

METHODS

A cross-sectional study was conducted with 212 participants to investigate the effects of a digital learning system on care quality.

RESULTS

After the implementation of the digital learning system, intensive care unit nurses' critical care knowledge and critical thinking skills increased significantly. High-level nurses had higher critical thinking scores. All participants associated critical care knowledge with improved quality of care.

CONCLUSION

The digital learning management system enhanced intensive care unit nurses' critical care knowledge. Optimizing nursing care safety and quality requires that nursing staff to be at an adequate level, which improves their critical care ability.

IMPLICATIONS FOR NURSING MANAGEMENT

A well-designed digital learning management system with structured classes may allow intensive care unit nurses to learn effectively and can be used for continuing education. These results are of interest to nursing management staff who want to invest in the continued professional development of intensive care unit nurses to improve critical care knowledge, critical thinking skills, care quality, and health care value.

Feasibility, utility, and safety of fully incorporating transesophageal echocardiography into emergency medicine practice

INTRODUCTION

Transthoracic echocardiography (TTE) is a standard procedure for emergency physicians (EPs). Transesophageal echocardiography (TEE) is known to have great utility in patients who are critically ill or in cardiac arrest and has been used by some EPs with specialized ultrasound (US) training, but it is generally considered outside the reach of the majority of EPs. We surmised that all of our EPs could learn to perform focused TEE (F-TEE), so we trained and credentialed all of the physicians in our group.

METHODS

We trained 52 EPs to perform and interpret F-TEEs using a 4-h simulator-based course. We kept a database of all F-TEE examinations for quality assurance and continuous quality feedback. Data are reported using descriptive statistics.

RESULTS

Emergency physicians attempted 557 total F-TEE examinations (median = 10, interquartile range = 5-15) during the 42-month period following training. Clinically relevant images were obtained in 99% of patients. EPs without fellowship or other advanced US training performed the majority of F-TEEs (417, 74.9%) and 94.3% (95% confidence interval [CI] = 91.4%-96.3%) had interpretable images recorded. When TTE and TEE were both performed (n = 410), image quality of TEE was superior in 378 (93.3%, 95% CI = 89.7%-95%). Indications for F-TEE included periarrest states (55.7%), cardiac arrest (32.1%), and shock (12.2%). There was one case of endotracheal tube dislodgement during TEE placement, but this was immediately identified and replaced without complication.

CONCLUSION

After initiating a mandatory group F-TEE training and credentialing program, we report the largest series to date of EP-performed resuscitative F-TEE. The majority of F-TEE examinations (75%) were performed by EPs without advanced US training beyond residency.

Critical care echocardiography in prone position patients during COVID-19 pandemic: a feasibility study

Purpose

Critical care echocardiography is a fundamental tool in the hemodynamic evaluation of critically ill patients and prone position ventilation might limit its application. We aim to evaluate the feasibility of transthoracic echocardiography to assess different measurements performed in prone vs supine position in patients during COVID-19 pandemic to answer our research question: What is the feasibility of classic echocardiographic measurements in COVID-19 patients in prone position ventilation?

Methods

Patients with covid-19 admitted to ICUs in four academic hospitals with respiratory failure and on mechanical ventilation were evaluated with critical care echocardiography. The first ultrasound assessment was compared between prone and supine patients recording feasibility of several echocardiographic measurements, using Fisher’s exact test complementing with Crombach’s Alpha.

Results

139 patients were included. Sixty-eight (49%) were evaluated in prone position and seventy one (51%) in supine position. Most variables were highly feasible, left ventricular volumes and ejection fraction were more possible to obtain in prone position, while cardiac output was in supine position. Tricuspid regurgitation was the least feasible overall measurement.

Conclusion

Prone position ultrasound achieved a high feasibility of measurements compared with supine ultrasound in critically ill patients with COVID-19 respiratory failure and on mechanical ventilation.

Registration

Post hoc analysis of Echo-COVID study (NTC04628195, registered November 13, 2020, retrospectively registered).

Application of Controlled Hypotension During Surgery for Spinal Metastasis

With advances in tumor treatment, metastasis to bone is increasing, and surgery has become the only choice for most terminal patients. However, spinal surgery has a high risk and is prone to heavy bleeding. Controlled hypotension during surgery has outstanding advantages in reducing intraoperative bleeding and ensuring a clear field of vision, thus avoiding damage to important nerves and vessels. Antihypertensive drugs should be carefully selected after considering the patient's age, different diseases, etc, and a single or combined regimen can be used. Hypotension also inevitably leads to a decrease in perfusion of important organs, so the threshold of hypotension and the maintenance time of hypotension should be strictly limited, and the monitoring of important organs during the operation is particularly important. Information such as blood perfusion, blood oxygen saturation, cardiac output, and neurophysiological conduction potential changes should be obtained in a timely fashion, which will help to reduce the risk of hypotension. In short, when applying controlled hypotension, it is necessary to choose an appropriate threshold and duration, and appropriate monitoring should be conducted during the operation to ensure the safety of the patient.

Transthoracic echocardiography of patients in prone position ventilation during the COVID-19 pandemic: an observational and retrospective study

Mechanical ventilation in prone position is a strategy that increases oxygenation and reduces mortality in severe ARDS. The hemodynamic and cardiovascular assessment of these patients is essential. Transthoracic echocardiography (TTE) is a widely used tool to assess hemodynamics in critical care, but the prone position is thought to limit adequate TTE views and goal-oriented measurements. The aim of this study is to show the feasibility of the hemodynamic assessment by transthoracic echocardiography during prone position ventilation (PPV). This is a retrospective, observational study, carried out in the intensive care unit (ICU) of a tertiary-care center in Buenos Aires, Argentina. We included all the adult patients admitted to the ICU between March 2020 and August 2021 who had a TTE examination in PPV due to ARDS. During the study period, we evaluated by TTE a total of 35 patients requiring PPV. The vast majority of the patients had COVID-19 pneumonia (91.4%). In 33 out of 35 (94.3%) cases, it was able to achieve an adequate apical four chamber view. We assessed qualitatively the systolic function of left ventricle (LV) and right ventricle (RV) in all of the successfully evaluated patients. We measured the RV basal diameter (94.3%), RV/LV ratio (77.1%), tricuspid annular plane systolic excursion (TAPSE) (91.4%), and septal mitral annular plane systolic excursion (MAPSE) (88.5%) in most of them. Also, we quantified the left ventricle outflow tract velocity time integral (LVOT VTI) in a large part (68.5%) of the examinations. Transthoracic echocardiography is a useful tool for the hemodynamic assessment of patients in prone position under mechanical ventilation.

Ten answers to key questions for fluid management in intensive care

This review focuses on fluid management of critically ill patients. The topic is addressed based on 10 single questions with simplified answers that provide clinicians with the basic information needed at the point of care in treating patients in the Intensive Care Unit. The review has didactic purposes and may serve both as an update on fluid management and as an introduction to the subject for novices in critical care. There is an urgent need to increase awareness regarding the potential risks associated with fluid overload. Clinicians should be mindful not only of the indications for administering fluid loads and of the type of fluids administered, but also of the importance to set safety limits. Lastly, it is important to implement proactive strategies seeking to establish negative fluid balance as soon as the clinical conditions are considered to be stable and the risk of deterioration is low.

Ultrasound and Other Advanced Hemodynamic Monitoring Techniques in the Intensive Care Unit

The ideal device for hemodynamic monitoring of critically ill patients in the intensive care unit (ICU) or the operating room has not yet been developed. This would need to be affordable, consistent, have a very low margin of error (<30%), be minimally or noninvasive, and allow the clinician to make a reasonable therapeutic decision that consistently led to better outcomes. Such a device does not yet exist. This article will describe the distinct options we, as critical care physicians, currently possess for this Herculean endeavor.

Value of early critical care transthoracic echocardiography for patients undergoing mechanical ventilation: a retrospective study

OBJECTIVES

To evaluate whether early intensive care transthoracic echocardiography (TTE) can improve the prognosis of patients with mechanical ventilation (MV).

DESIGN

A retrospective cohort study.

SETTING

Patients undergoing MV for more than 48 hours, based on the Medical Information Mart for Intensive Care III (MIMIC-III) database and the eICU Collaborative Research Database (eICU-CRD), were selected.

PARTICIPANTS

2931 and 6236 patients were recruited from the MIMIC-III database and the eICU database, respectively.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was in-hospital mortality. Secondary outcomes were 30-day mortality from the date of ICU admission, days free of MV and vasopressors 30 days after ICU admission, use of vasoactive drugs, total intravenous fluid and ventilator settings during the first day of MV.

RESULTS

We used propensity score matching to analyse the association between early TTE and in-hospital mortality and sensitivity analysis, including the inverse probability weighting model and covariate balancing propensity score model, to ensure the robustness of our findings. The adjusted OR showed a favourable effect between the early TTE group and in-hospital mortality (MIMIC: OR 0.78; 95% CI 0.65 to 0.94, p=0.01; eICU-CRD: OR 0.76; 95% CI 0.67 to 0.86, p<0.01). Early TTE was also associated with 30-day mortality in the MIMIC database (OR 0.71, 95% CI 0.57 to 0.88, p=0.001). Furthermore, those who had early TTE had both more ventilation-free days (only in eICU-CRD: 23.48 vs 24.57, p<0.01) and more vasopressor-free days (MIMIC: 18.22 vs 20.64, p=0.005; eICU-CRD: 27.37 vs 28.59, p<0.001) than the control group (TTE applied outside of the early TTE and no TTE at all).

CONCLUSIONS

Early application of critical care TTE during MV is beneficial for improving in-hospital mortality. Further investigation with prospectively collected data is required to validate this relationship.

Transesophageal Echocardiography Performed by Intensivist and Emergency Physicians-A 5-Year, Single-Center Experience

Purpose: Data on the use of transesophageal echocardiography (TEE) by intensivist physicians (IP) and emergency physicians (EP) are limited. This study aims to characterize the use of TEE by IPs and EPs in critically ill patients at a single center in the United States. Materials and Methods: Retrospective chart review of all critical care TEEs performed from January 1, 2016 to January 31, 2021. The personnel performing the exams, location of the exams, characteristics of exams, complications, and outcome of the patients were reviewed. Results: A total of 396 examinations was reviewed. TEE was performed by IPs (92%) and EPs (9%). The location of TEE included: intensive care unit (87%), emergency department (11%), and prehospital (2%) settings. The most common indications for TEE were: hemodynamic instability/shock (44%), cardiac arrest (23%), and extracorporeal membrane oxygenation (ECMO) facilitation, adjustment, or weaning (21%). The most common diagnosis based on TEE were: normal TEE (25%), left ventricular dysfunction (19%), and vasodilatory shock (15%). A management change resulted from 89% of exams performed. Complications occurred in 2% of critical care TEEs. Conclusion: TEE can be successfully performed by IPs and EPs on critically ill patients in multiple clinical settings. TEE frequently informed management changes with few complications.

An Approach to Standard Perioperative Transthoracic Echocardiography Practice for Anesthesiologists-Perioperative Transthoracic Echocardiography Protocols

The use of intraoperative transesophageal echocardiography (TEE) has become the standard of care for most cardiac surgical procedures. There are guidelines established for training, practice, and quality improvement in perioperative TEE by the joint efforts of the American Society of Echocardiography and Society of Cardiovascular Anesthesiologists. Cardiac point-of-care ultrasound (POCUS) increasingly is being incorporated into anesthesiologists' training and practice. While a special "certification in Critical Care Echocardiography" was created by the National Board of Echocardiography in 2019, there currently exist no guidelines for training, certification, and practice of perioperative TTE by anesthesiologists. In this review, the authors describe the categories, indications and applications of perioperative TTE and provide a recommended sequence for performing an examination tailored to the evaluation of perioperative patients. Although the authors describe a protocol utilized at their institution, there are no standards described in the literature for PTTE. Cardiac anesthesiologists and cardiac anesthesia societies (Society of Cardiovascular Anesthesiologists, European Association of Cardiothoracic Anesthesiologists) must come forward to establish standards working in collaboration with echocardiography societies (American Society of Echocardiography, European Society of Cardiology).

Comprehensive Assessment of Fluid Status by Point-of-Care Ultrasonography

The management of complex fluid and electrolyte disorders is central to the practice of nephrologists. The sensitivity of physical examination alone to determine fluid status is limited, precluding accurate clinical decision making. Point-of-care ultrasonography (POCUS) is emerging as a valuable, noninvasive, bedside diagnostic tool for objective evaluation of physiologic and hemodynamic parameters related to fluid status, tolerance, and responsiveness. Rapid bedside sonographic evaluation can obtain qualitative data on cardiac function and quantitative data on pulmonary congestion. Advanced POCUS, including goal-directed Doppler echocardiography, provides additional quantitative information, including flow velocities and pressures across the cardiac structures. Recently, abnormal Doppler flow patterns in abdominal organs secondary to increased right atrial pressure have been linked to congestive organ damage, adding another component to the hemodynamic assessment. Integrating POCUS findings with clinical and laboratory data can further elucidate a patient's hemodynamic status. This drives decisions regarding crystalloid administration or, conversely, diuresis or ultrafiltration and allows tailored therapy for individual patients. In this article, we provide an overview of the focused assessment of cardiovascular function and pulmonary and venous congestion using POCUS and review relevant literature.

Comprehensive Assessment of Fluid Status by Point-of-Care Ultrasonography

The management of complex fluid and electrolyte disorders is central to the practice of nephrologists. The sensitivity of physical examination alone to determine fluid status is limited, precluding accurate clinical decision making. Point-of-care ultrasonography (POCUS) is emerging as a valuable, noninvasive, bedside diagnostic tool for objective evaluation of physiologic and hemodynamic parameters related to fluid status, tolerance, and responsiveness. Rapid bedside sonographic evaluation can obtain qualitative data on cardiac function and quantitative data on pulmonary congestion. Advanced POCUS, including goal-directed Doppler echocardiography, provides additional quantitative information, including flow velocities and pressures across the cardiac structures. Recently, abnormal Doppler flow patterns in abdominal organs secondary to increased right atrial pressure have been linked to congestive organ damage, adding another component to the hemodynamic assessment. Integrating POCUS findings with clinical and laboratory data can further elucidate a patient's hemodynamic status. This drives decisions regarding crystalloid administration or, conversely, diuresis or ultrafiltration and allows tailored therapy for individual patients. In this article, we provide an overview of the focused assessment of cardiovascular function and pulmonary and venous congestion using POCUS and review relevant literature.

POCUS for Nephrologists: Basic Principles and a General Approach

Point-of-care ultrasonography (POCUS) has evolved as a valuable adjunct to physical examination in the recent past and various medical specialties have embraced it. However, POCUS training and scope of practice remain relatively undefined in nephrology. The utility of diagnostic POCUS beyond kidney and vascular access is under-recognized. Assessment of fluid status is a frequent dilemma faced by nephrologists in day-to-day practice where multiorgan POCUS can enhance the sensitivity of conventional physical examination. POCUS also reduces fragmentation of care, facilitates timely diagnosis, and expedites management. Although the need for further imaging studies is obviated in selected patients, POCUS is not meant to serve as an alternative to consultative imaging. In addition, the utility of POCUS depends on the skills and experience of the operator, which in turn depend on the quality of training. In this review, we discuss the rationale behind nephrologists performing POCUS, discuss patient examples to illustrate the basic principles of focused ultrasonography, and share our experience-based opinion about developing a POCUS training program at the institutional level.

Educational initiatives for electroencephalography in the critical care setting: a systematic review and meta-analysis

PURPOSE

We systematically reviewed existing critical care electroencephalography (EEG) educational programs for non-neurologists, with the primary goal of reporting the content covered, methods of instruction, overall duration, and participant experience. Our secondary goals were to assess the impact of EEG programs on participants' core knowledge, and the agreement between non-experts and experts for seizure identification.

SOURCE

Major databases were searched from inception to 30 August 2020. Randomized controlled trials, cohort studies, and descriptive studies were all considered if they reported an EEG curriculum for non-neurologists in a critical care setting. Data were presented thematically for the qualitative primary outcome and a meta-analysis using a random effects model was performed for the quantitative secondary outcomes.

PRINCIPAL FINDINGS

Twenty-nine studies were included after reviewing 7,486 citations. Twenty-two studies were single centre, 17 were from North America, and 16 were published after 2016. Most EEG studies were targeted to critical care nurses (17 studies), focused on processed forms of EEG with amplitude-integrated EEG being the most common (15 studies), and were shorter than one day in duration (24 studies). In pre-post studies, EEG programs significantly improved participants' knowledge of tested material (standardized mean change, 1.79; 95% confidence interval [CI], 0.86 to 2.73). Agreement for seizure identification between non-experts and experts was moderate (Cohen's kappa = 0.44; 95% CI, 0.27 to 0.60).

CONCLUSIONS

It is feasible to teach basic EEG to participants in critical care settings from different clinical backgrounds, including physicians and nurses. Brief training programs can enable bedside providers to recognize high-yield abnormalities such as non-convulsive seizures.

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.

Clinical Application of Machine Learning-Based Artificial Intelligence in the Diagnosis, Prediction, and Classification of Cardiovascular Diseases

With the rapid development of artificial intelligence (AI) and machine learning (ML), as well as the arrival of the big data era, technological innovations have occurred in the field of cardiovascular medicine. First, the diagnosis of cardiovascular diseases (CVDs) is highly dependent on assistive examinations, the interpretation of which is time consuming and often limited by the knowledge level and clinical experience of doctors; however, AI could be used to automatically interpret the images obtained in auxiliary examinations. Second, some of the predictions of the incidence and prognosis of CVDs are limited in clinical practice by the use of traditional prediction models, but there may be occasions when AI-based prediction models perform well by using ML algorithms. Third, AI has been used to assist precise classification of CVDs by integrating a variety of medical data from patients, which helps better characterize the subgroups of heterogeneous diseases. To help clinicians better understand the applications of AI in CVDs, this review summarizes studies relating to AI-based diagnosis, prediction, and classification of CVDs. Finally, we discuss the challenges of applying AI to cardiovascular medicine.

Echocardiographic Characteristics and Outcome in Patients With COVID-19 Infection and Underlying Cardiovascular Disease

Background: The cardiac manifestations of coronavirus disease 2019 (COVID-19) patients with cardiovascular disease (CVD) remain unclear. We aimed to investigate the prognostic value of echocardiographic parameters in patients with COVID-19 infection and underlying CVD.

Methods: One hundred fifty-seven consecutive hospitalized COVID-19 patients were enrolled. The left ventricular (LV) and right ventricular (RV) structure and function were assessed using bedside echocardiography.

Results: Eighty-nine of the 157 patients (56.7%) had underlying CVD. Compared with patients without CVD, those with CVD had a higher mortality (22.5 vs. 4.4%, p = 0.002) and experienced more clinical events including acute respiratory distress syndrome, acute heart injury, or deep vein thrombosis. CVD patients presented with poorer LV diastolic and RV systolic function compared to those without CVD. RV dysfunction (30.3%) was the most frequent, followed by LV diastolic dysfunction (9.0%) and LV systolic dysfunction (5.6%) in CVD patients. CVD patients with high-sensitivity troponin I (hs-TNI) elevation or requiring mechanical ventilation therapy demonstrated worsening RV function compared with those with normal hs-TNI or non-intubated patients, whereas LV systolic or diastolic function was similar. Impaired RV function was associated with elevated hs-TNI level. RV function and elevated hs-TNI level were independent predictors of higher mortality in COVID-19 patients with CVD.

Conclusions: Patients with COVID-19 infection and underlying CVD displayed impaired LV diastolic and RV function, whereas LV systolic function was normal in most patients. Importantly, RV function parameters are predictive of higher mortality.

Echocardiographic Parameters and Mortality in Pediatric Sepsis: A Systematic Review and Meta-Analysis

OBJECTIVE

We conducted a systematic review and meta-analysis to investigate the prognostic value of echocardiographic parameters in pediatric septic patients.

DATA SOURCES

MEDLINE, PubMed, and EMBASE (last update April 5, 2020).

STUDY SELECTION

Observational studies of pediatric sepsis providing echocardiographic parameters in relation to mortality.

DATA EXTRACTION

Echocardiography data were categorized as those describing left ventricular systolic or diastolic function, right ventricular function, and strain echocardiography parameters. Data from neonates and children were considered separately. Analysis is reported as standardized mean difference and 95% CI.

DATA SYNTHESIS

We included data from 14 articles (n = 5 neonates, n = 9 children). The fractional shortening was the most commonly reported variable (11 studies, n = 555 patients) and we did not identify an association with mortality (standardized mean difference 0.22, 95% CI [-0.02 to 0.47]; p = 0.07, I2 = 28%). In addition, we did not find any association with mortality also for left ventricular ejection fraction (nine studies, n = 417; standardized mean difference 0.06, 95% CI [-0.27 to 0.40]; p = 0.72, I2 = 51%), peak velocity of systolic mitral annular motion determined by tissue Doppler imaging wave (four studies, n = 178; standardized mean difference -0.01, 95% CI [-0.34 to 0.33]; p = 0.97, I2 = 0%), and myocardial performance index (five studies, n = 219; standardized mean difference -0.51, 95% CI [-1.10 to 0.08]; p = 0.09, I2 = 63%). However, in regard to left ventricular diastolic function, there was an association with mortality for higher early wave of transmitral flow/peak velocity of early diastolic mitral annular motion determined by tissue Doppler imaging ratio (four studies, n = 189, standardized mean difference -0.45, 95% CI [-0.80 to -0.10]; p = 0.01, I2 = 0%) or lower peak velocity of early diastolic mitral annular motion determined by tissue Doppler imaging wave (three studies, n = 159; standardized mean difference 0.49, 95% CI [0.13-0.85]; p = 0.008, I2 = 0%). We did not find any association with mortality for early wave of transmitral flow/late (atrial) wave of trans-mitral flow ratio (six studies, n = 273; standardized mean difference 0.28, 95% CI [-0.42 to 0.99]; p = 0.43, I2 = 81%) and peak velocity of systolic mitral annular motion determined by tissue Doppler imaging wave measured at the tricuspid annulus (three studies, n = 148; standardized mean difference -0.18, 95% CI [-0.53 to 0.17]; p = 0.32, I2 = 0%). Only a few studies were conducted with strain echocardiography.

CONCLUSIONS

This meta-analysis of echocardiography parameters in pediatric sepsis failed to find any association between the measures of left ventricular systolic or right ventricular function and mortality. However, mortality was associated with higher early wave of transmitral flow/peak velocity of early diastolic mitral annular motion determined by tissue Doppler imaging or lower peak velocity of early diastolic mitral annular motion determined by tissue Doppler imaging, indicating possible importance of left ventricular diastolic dysfunction. These are preliminary findings because of high clinical heterogeneity in the studies to date.

Retention of Point-of-Care Ultrasound Skills Among Practicing Physicians: Findings of the VA National POCUS Training Program

BACKGROUND

Point-of-care ultrasound (POCUS) use continues to increase in many specialties, but lack of POCUS training is a known barrier among practicing physicians. Many physicians are obtaining POCUS training through postgraduate courses, but the impact of these courses on skill retention and frequency of POCUS use post-course is unknown. The purpose of this study was to assess the change in POCUS knowledge, skills, and frequency of use after 6-9 months of participating in a brief training course.

METHODS

Course participants' POCUS knowledge and hands-on technical skills were tested pre-course using an online, 30-question knowledge test and a directly observed skills test, respectively. The same knowledge and skills tests were repeated immediately post-course and after 6-9 months using remote tele-ultrasound software. Course participants completed a survey on their POCUS use pre-course and after 6-9 months post-course.

RESULTS

There were 127 providers who completed the POCUS training course from October 2016 to November 2017. Knowledge test scores increased from a median of 60% to 90% immediately post-course followed by a slight decrease to 87% after 8 months post-course. Median skills test scores for 4 common POCUS applications (heart, lung, abdomen, vascular access) increased 36-74 points from pre-course to immediately post-course with a 2-7-point decrease after 8 months. Providers reported more frequent POCUS use post-course, which suggests application of their POCUS knowledge and skills in clinical practice. More frequent use of cardiac POCUS applications was associated with significantly greater retention of cardiac skills at 8 months.

CONCLUSIONS

Practicing physicians can retain POCUS knowledge and hands-on skills 8 months after participating in a 2.5-day POCUS training course, regardless of frequency of POCUS use post-course.

Could strain echocardiography help to assess systolic function in critically ill COVID-19 patients?

Strain echocardiography enables the automatic quantification of the global longitudinal strain (GLS), which is a direct measure of ventricular shortening during systole. In the current context of overwhelmed ICUs and clinician shortage, GLS has the advantage to be quick and easy to measure by non-experts. However, little is known regarding its value to assess bi-ventricular systolic function in critically ill COVID-19 patients. Therefore, we designed a study to compare right and left ventricular GLS with classic echo-Doppler indices of systolic function, namely the ejection fraction for the left ventricle (LVEF) and the fractional area change (FAC), the tricuspid annular plane systolic excursion (TAPSE), and the tissue Doppler velocity of the basal free lateral wall (S’) for the right ventricle. Eighty transthoracic echocardiographic evaluations done in 30 ICU patients with COVID-19 were analyzed. We observed a fair relationship (r = 0.73, p < 0.01) between LVEF and left ventricular GLS. The GLS cut-off value of − 22% identified a LVEF < 50% with a sensitivity of 63% and a specificity of 80%. All patients with a GLS > − 17% had a LVEF < 50%. Although statistically significant, relationships between FAC (r = 0.41, p < 0.01), TAPSE (r = 0.26, p < 0.05) and right ventricular GLS were weak. S’ was not correlated with right ventricular GLS. In conclusion, left ventricular GLS was useful to assess left ventricular systolic function. However, right ventricular GLS was poorly correlated with FAC, TAPSE and S’. Further studies are needed to clarify what is the best method to assess right ventricular systolic function in ICU patients with COVID-19.

Respiratory Variations in Peak Peripheral Artery Velocities and Waveforms for Rapid Assessment of Fluid Responsiveness in Traumatic Shock Patients

Background

This study aimed to assess the correlation between the variability of the end-inspiratory and end-expiratory blood flow waveform and fluid responsiveness (FR) in traumatic shock patients who underwent mechanical ventilation by evaluating peripheral arterial blood flow parameters.

Material/Methods

A cohort of 60 patients with traumatic shock requiring mechanical ventilation-controlled breathing received ultrasound examinations to assess the velocity of carotid artery (CA), femoral artery (FA) and brachial artery (BA). A rehydration test was performed in which of 250 mL of 0.9% saline was administered within 30 min between the first and second measurement of cardiac output by echocardiography. Then, all patients were divided into 2 groups, a responsive group (FR+) and a non-responsive group (FR−). The velocity of end-inspiratory and end-expiratory peripheral arterial blood flow of all patients was ultrasonically measured, and the variability were measured between end-inspiratory and end-expiratory.

Results

The changes in the end-inspiratory and end-expiratory carotid artery blood flow velocity waveforms of the FR+ groups were significantly different from those of the FR− group (P<0.001). A statistically significant difference in ΔVmax (CA), ΔVmax (BA), and ΔVmax (FA) between these 2 groups was found (all P<0.001). The ROC curve showed that ΔVmax (CA) and ΔVmax (BA) were more sensitive values to predict FR compared to ΔVmax (FA). The sensitivity of ΔVmax (CA), ΔVmax (FA), and ΔVmax (BA) was 70.0%, 86.7%, and 93.3%, respectively.

Conclusions

The study showed that periodic velocity waveform changes in the end-inspiratory and end-expiratory peripheral arterial blood flow can be used for quick assessment of fluid responsiveness.

Systolic dysfunction as evaluated by tissue Doppler imaging echocardiography and mortality in septic patients: A systematic review and meta-analysis

PURPOSE

Septic induced cardiomyopathy has a wide spectrum of presentation, being associated with systolic and/or diastolic dysfunction. There is currently no evidence of association between left ventricular (LV) systolic dysfunction and mortality in septic patients.

METHODS

We conducted a systematic review and meta-analysis to investigate the association between systolic wave (s') obtained with Tissue Doppler Imaging (TDI) and mortality in septic patients. Secondary outcome was the association of LV ejection fraction with mortality.

RESULTS

In the primary analysis we included a total of 13 studies (1197 patients, mortality 39.9%); overall s' wave was not significantly different between survivors and non-survivors (Standardized Mean Difference 0.20, 95%Confidence-Interval - 0.18, 0.59). This result was confirmed also in sub-groups analyses according to regional criteria of TDI sampling. A post-hoc analysis including only septic shock patients confirmed that s' wave was not associated with mortality. Several sensitivity analyses confirmed these results. We found no evidence of publication bias. The secondary analysis (11 studies, 1081 patients, mortality 36.7%) showed that LV ejection fraction was not associated with mortality (Mean Difference 0.98, 95% Confidence-Interval - 1.79,3.75).

CONCLUSIONS

There is no association between mortality and LV systolic function as evaluated by TDI s' wave in septic patients.

Ten answers to key questions for fluid management in intensive care

This review focuses on fluid management of critically ill patients. The topic is addressed based on 10 single questions with simplified answers that provide clinicians with the basic information needed at the point of care in treating patients in the Intensive Care Unit. The review has didactic purposes and may serve both as an update on fluid management and as an introduction to the subject for novices in critical care. There is an urgent need to increase awareness regarding the potential risks associated with fluid overload. Clinicians should be mindful not only of the indications for administering fluid loads and of the type of fluids administered, but also of the importance to set safety limits. Lastly, it is important to implement proactive strategies seeking to establish negative fluid balance as soon as the clinical conditions are considered to be stable and the risk of deterioration is low.