Early detection of right ventricular dysfunction using transthoracic echocardiography in ARDS: a more objective approach

Right ventricular dysfunction in the critically ill. Echocardiographic evaluation

Right ventricular dysfunction is common in critically ill patients, and is associated with increased mortality. Its diagnosis moreover remains challenging. In this review, we aim to outline the potential mechanisms underlying abnormal biomechanics of the right ventricle and the different injury phenotypes. A comprehensive understanding of the pathophysiology and natural history of right ventricular injury can be informative for the intensivist in the diagnosis and management of this condition, and may serve to guide individualized treatment strategies. We describe the main recommended parameters for assessing right ventricular systolic and diastolic function. We also define how to evaluate cardiac output and pulmonary circulation pressures with echocardiography, with a focus on the diagnosis of acute cor pulmonale and relevant applications in critical disorders such as distress, septic shock, and right ventricular infarction.

Effect of caspase inhibitors on hemodynamics and inflammatory factors in ARDS model rats

To study the effects of caspase inhibitors on hemodynamics and inflammatory factors in acute respiratory distress syndrome (ARDS) model rats. Sixty healthy male Wistar rats were randomly divided into three groups, namely, the control group, ARDS group and ARDS + Caspase inhibitor group, with 20 rats in each group. The control group was intraperitoneally injected with 2 mL/kg saline, and the ARDS model group was established by intraperitoneally injecting 4 mg/kg Lipopolysaccharide (LPS), ARDS + Caspase inhibitor group was adminstered 20 mg/kg caspase inhibitor after intraperitoneal LPS injection. Changes in pulmonary arterial pressure (PAP) and mean arterial pressure (MAP) at 6 and 12 h before and after administration were recorded. Moreover, arterial blood gas was evaluated with a blood gas analyzer and changes in the partial pressure of O2 (PaO2), partial pressure of CO2 (PaCO2), partial pressure of O2/fraction of inspired O2 (PaO2/FiO2) were evaluated. In addition, the lung wet/dry weight (W/D) ratio and inflammatory factor levels in lung tissue were determined. Finally, pathological sections were used to determine the pulmonary artery media thickness (MT), MT percentage (MT%), and the degree of muscle vascularization. The pulmonary arterial pressure of rats was determined at several time points. Compared with the control group, the model group had a significantly increased pulmonary arterial pressure at each time point (P < 0.01), and the mean arterial pressure significantly increased at 6 h (P < 0.05). Compared with that of rats in the model group, the pulmonary arterial pressure of rats in drug administration group was significantly reduced at each time point after administration (P < 0.01), and the mean arterial pressure was significantly reduced at 6 h (P < 0.05). The arterial blood gas analysis showed that compared with those in the control group, PaO2, PaCO2 and PaO2/FiO2 in the model group were significantly reduced (P < 0.01), and PaO2, PaCO2 and PaO2/FiO2 were significantly increased after caspase inhibitor treatment (P < 0.05 or 0.01). The levels of the inflammatory mediators tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in the model group were significantly higher than those in the control group (P < 0.01), and they were significantly decreased after caspase inhibitor treatment (P < 0.01). In the model group, pulmonary artery MT, MT% and the degree of muscle vascularization were significantly increased (P < 0.05 or 0.01), and pulmonary artery MT and the degree of muscle vascularization were significantly reduced after caspase inhibitor treatment (P < 0.05 or 0.01). Apoptosis Repressor with a Caspase Recuitment Domain (ARC) can alleviate the occurrence and development of pulmonary hypertension (PH) by affecting hemodynamics and reducing inflammation.

Assessing Right Ventricle Over Time in Patients on Veno-Venous Extracorporeal Membrane Oxygenation: Insights From Serial Echocardiography

Extracorporeal membrane oxygenation (ECMO) is often used in acute respiratory distress syndrome (ARDS) with refractory hypoxemia. There is limited literature highlighting the development of right ventricular (RV) failure while on ECMO. We conducted a retrospective multicenter observational study including 70 patients who were placed on veno-venous (VV)-ECMO for respiratory failure at Mayo Clinic, Jacksonville, and Mayo Clinic, Rochester, between January 2018 and June 2022 and had at least two post-ECMO transthoracic echoes. The primary outcomes were the incidence and progression of RV dysfunction and dilatation. The secondary outcome was in-patient mortality. Among 70 patients in our cohort, 60.6% had a normal RV function at the time of ECMO placement, whereas only 42% had a normal RV function at the second post-ECMO echo. On multinomial regression, a moderate decrease in RV function was associated with ECMO flow (odds ratio [OR] = 2.32, p = 0.001) and ECMO duration (OR = 1.01, p = 0.01). A moderately dilated RV size was also associated with ECMO flow (OR = 2.62, p < 0.001) and ECMO duration (OR = 1.02, p = 0.02). An increasing degree of RV dysfunction was associated with worse outcomes. Our study showed that the increasing duration and flow of VV-ECMO correlated with progressive RV dilatation and dysfunction, which were associated with poor survival.

Reference values and the Z-score values of tricuspid annular plane systolic excursion in Chinese children

To establish age-specific and body surface area (BSA)-specific reference values of Tricuspid Annular Plane Systolic Excursion (TAPSE) for children under 15 years old in China. A retrospective study was conducted in Children's Hospital Attached to the Capital Institute of Pediatrics. A total of 702 cases were included in this research to establish reference values of TAPSE in Chinese children. SPSS 25.0 (IBM) was used for data analysis. Lambda-mu-sigma method was used to calculate and construct the age-specific and BSA-specific percentiles and Z-score curves of TAPSE. The mean value of TAPSE increased with age and BSA from 0 to 15 years in a nonlinear way and reached the adult threshold (17 mm) until 1 year old. There was no difference between genders. TAPSE values increased with age and BSA in Chinese children aged between 0 and 15 years and there was no difference between boys and girls. A prospective, multicenter cohort study from different parts of China is supposed to be conducted in the future to reflect the whole spectrum of TAPSE in Chinese children.

Association of Right Ventricular Dilation and Dysfunction on Echocardiogram with In-Hospital Mortality Among Patients Hospitalized with COVID-19 Compared with Other Acute Respiratory Illness

BACKGROUND

Although right ventricular (RV) dysfunction is associated with mortality in acute COVID-19, the role of RV dilation is uncertain. The prognostic significance of RV dilation and dysfunction among hospitalized patients with acute COVID-19 compared to other respiratory illnesses.

METHODS

We conducted a retrospective cohort study to examine 225 consecutive adults admitted for acute COVID-19 and 6,150 control adults admitted for influenza, pneumonia or ARDS who had a clinical echocardiogram performed. We used logistic regression models to assess associations between RV parameters and in-hospital mortality adjusted for confounders.

RESULTS

Among those with COVID-19, 48/225 (21.3%) died during the index hospitalization compared to 727/6150 (11.8%) with other respiratory illness (p=0.001). Independent of COVID-19, mild and moderate to severe RV dilation were associated with 1.4 and 2.0 times higher risk of inpatient mortality, respectively (95%CI 1.17 to 1.69; p=0.0003; 95%CI 1.62 to 2.47; p<0.0001, respectively). Similarly, mild and moderate RV dysfunction were associated with 1.4 and 1.7 times higher risk of inpatient mortality (95%CI 1.10 to 1.77; p=0.007; 95%CI 1.17 to 2.42; p=0.005, respectively). Relative to normal RV size and non-COVID-19 acute respiratory illness, mild and moderate RV dilation were associated with 1.4 times and 2.0 times higher risk among those without COVID-19 and 1.9 times higher and 3.0 times higher risk among those with COVID-19, with similar findings for RV dysfunction. Having both RV dilation and dysfunction or RV dilation alone were associated with 1.7 times higher risk while RV dysfunction alone was associated with 1.4 times higher risk compared to normal RV size and function.

CONCLUSIONS

RV dilation and dysfunction are associated with increased risk of inpatient mortality among those with COVID-19 and other respiratory illnesses. Abnormal RV findings may identify those at higher risk of short-term mortality from acute respiratory illness including COVID-19 beyond other risk markers.

Utility of echocardiographic right ventricular subcostal strain in critical care

AIMS

Right ventricular (RV) strain is a known predictor of outcomes in various heart and lung pathologies but has been considered too technically challenging for routine use in critical care. We examined whether RV strain acquired from the subcostal view, frequently more accessible in the critically ill, is an alternative to conventionally derived RV strain in intensive care.

METHODS AND RESULTS

RV strain data were acquired from apical and subcostal views on transthoracic echocardiography (TTE) in 94 patients (35% female), mean age 50.5 ± 15.2 years, venovenous extracorporeal membrane oxygenation (VVECMO) (44%). RV strain values from the apical (mean ± standard deviation; -20.4 ± 6.7) and subcostal views (-21.1 ± 7) were highly correlated (Pearson's r -0.89, P < 0.001). RV subcostal strain correlated moderately well with other echocardiography parameters including tricuspid annular plane systolic excursion (r -0.44, P < 0.001), RV systolic velocity (rho = -0.51, P < 0.001), fractional area change (r -0.66, P < 0.01), and RV outflow tract velocity time integral (r -0.49, P < 0.001). VVECMO was associated with higher RV subcostal strain (non-VVECMO -19.6 ± 6.7 vs. VVECMO -23.2 ± 7, P = 0.01) but not apical RV strain. On univariate analysis, RV subcostal strain was weakly associated with survival at 30 days (R2 = 0.04, P = 0.05, odds ratio =1.08) while apical RV was not (P = 0.16).

CONCLUSION 

RV subcostal deformation imaging is a reliable surrogate for conventionally derived strain in critical care and may in time prove to be a useful diagnostic marker in this cohort.

Bedside ultrasound in the management of critically ill patients; Echocardiographic signs of acute respiratory distress syndrome and pulmonary embolism can be very similar, and lung ultrasound can act as a key: A case report

Right-sided heart failure (RHF) diagnosed at point-of-care-ultrasonography examination of critical patients may reveal an acute disease, such as pulmonary embolism (PE), requiring emergency thrombolytic treatment. However, acute respiratory distress syndrome (ARDS) and PE leading to acute RHF may exhibit very similar echocardiographic features. We report the case of a 27-year-old pregnant woman diagnosed with ARDS due to septic abortion, and in whom ARDS mimicked PE both clinically and on echocardiography. Such similarity may lead to inappropriate administration of thrombolytic therapy and/or delay the correct treatment. Lung ultrasonography may help avoiding this pitfall.

Echocardiographic Features of Cardiac Injury Related to COVID-19 and Their Prognostic Value: A Systematic Review

BACKGROUND

The available information on the echocardiographic features of cardiac injury related to the novel coronavirus disease 2019 (COVID-19) and their prognostic value are scattered in the different literature. Therefore, the aim of this study was to investigate the echocardiographic features of cardiac injury related to COVID-19 and their prognostic value.

METHODS

Published studies were identified through searching PubMed, Embase (Elsevier), and Google scholar databases. The search was performed using the different combinations of the keywords "echocard*," "cardiac ultrasound," "TTE," "TEE," "transtho*," or "transeso*" with "COVID-19," "sars-COV-2," "novel corona, or "2019-nCOV." Two researchers independently screened the titles and abstracts and full texts of articles to identify studies that evaluated the echocardiographic features of cardiac injury related to COVID-19 and/or their prognostic values.

RESULTS

Of 783 articles retrieved from the initial search, 11 (8 cohort and 3 cross-sectional studies) met our eligibility criteria. Rates of echocardiographic abnormalities in COVID-19 patients varied across different studies as follow: RV dilatation from 15.0% to 48.9%; RV dysfunction from 3.6% to 40%; and LV dysfunction 5.4% to 40.0%. Overall, the RV abnormalities were more common than LV abnormalities. The majority of the studies showed that there was a significant association between RV abnormalities and the severe forms and death of COVID-19.

CONCLUSION

The available evidence suggests that RV dilatation and dysfunction may be the most prominent echocardiographic abnormality in symptomatic patients with COVID-19, especially in those with more severe or deteriorating forms of the disease. Also, RV dysfunction should be considered as a poor prognostic factor in COVID-19 patients.

Right ventricular dysfunction in critically ill COVID-19 ARDS

Aims

Comprehensive echocardiography assessment of right ventricular (RV) impairment has not been reported in critically ill patients with COVID-19. We detail the specific phenotype and clinical associations of RV impairment in COVID-19 acute respiratory distress syndrome (ARDS).

Methods

Transthoracic echocardiography (TTE) measures of RV function were collected in critically unwell patients for associations with clinical, ventilatory and laboratory data.

Results

Ninety patients (25.6% female), mean age 52.0 ± 10.8 years, veno-venous extracorporeal membrane oxygenation (VVECMO) (42.2%) were studied. A significantly higher proportion of patients were identified as having RV dysfunction by RV fractional area change (FAC) (72.0%,95% confidence interval (CI) 61.0–81.0) and RV velocity time integral (VTI) (86.4%, 95 CI 77.3–93.2) than by tricuspid annular plane systolic excursion (TAPSE) (23.8%, 95 CI 16.0–33.9), RVS’ (11.9%, 95% CI 6.6–20.5) or RV free wall strain (FWS) (35.3%, 95% CI 23.6–49.0). RV VTI correlated strongly with RV FAC (p ≤ 0.01). Multivariate regression demonstrated independent associations of RV FAC with NTpro-BNP and PVR. RV-PA coupling correlated with PVR (univariate p < 0.01), as well as RVEDAi (p < 0.01), and RVESAi (p < 0.01), and was associated with P/F ratio (p 0.026), PEEP (p 0.025), and ALT (p 0.028).

Conclusions

Severe COVID-19 ARDS is associated with a specific phenotype of RV radial impairment with sparing of longitudinal function. Clinicians should avoid interpretation of RV health purely on long-axis parameters in these patients. RV-PA coupling potentially provides important additional information above standard measures of RV performance in this cohort.

Inhaled Nitric Oxide Use in Pediatric Hypoxemic Respiratory Failure

OBJECTIVES

To characterize contemporary use of inhaled nitric oxide in pediatric acute respiratory failure and to assess relationships between clinical variables and outcomes. We sought to study the relationship of inhaled nitric oxide response to patient characteristics including right ventricular dysfunction and clinician responsiveness to improved oxygenation. We hypothesize that prompt clinician responsiveness to minimize hyperoxia would be associated with improved outcomes.

DESIGN

An observational cohort study.

SETTING

Eight sites of the Collaborative Pediatric Critical Care Research Network.

PATIENTS

One hundred fifty-one patients who received inhaled nitric oxide for a primary respiratory indication.

MEASUREMENTS AND MAIN RESULTS

Clinical data were abstracted from the medical record beginning at inhaled nitric oxide initiation and continuing until the earliest of 28 days, ICU discharge, or death. Ventilator-free days, oxygenation index, and Functional Status Scale were calculated. Echocardiographic reports were abstracted assessing for pulmonary hypertension, right ventricular dysfunction, and other cardiovascular parameters. Clinician responsiveness to improved oxygenation was determined. One hundred thirty patients (86%) who received inhaled nitric oxide had improved oxygenation by 24 hours. PICU mortality was 29.8%, while a new morbidity was identified in 19.8% of survivors. Among patients who had echocardiograms, 27.9% had evidence of pulmonary hypertension, 23.1% had right ventricular systolic dysfunction, and 22.1% had an atrial communication. Moderate or severe right ventricular dysfunction was associated with higher mortality. Clinicians responded to an improvement in oxygenation by decreasing FIO2 to less than 0.6 within 24 hours in 71% of patients. Timely clinician responsiveness to improved oxygenation with inhaled nitric oxide was associated with more ventilator-free days but not less cardiac arrests, mortality, or additional morbidity.

CONCLUSIONS

Clinician responsiveness to improved oxygenation was associated with less ventilator days. Algorithms to standardize ventilator management may improve signal to noise ratios in future trials enabling better assessment of the effect of inhaled nitric oxide on patient outcomes. Additionally, confining studies to more selective patient populations such as those with right ventricular dysfunction may be required.

New or Persistent Right Ventricular Systolic Dysfunction Is Associated With Worse Outcomes in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

The trajectory and importance of right ventricular systolic function and pulmonary hypertension during the course of pediatric acute respiratory distress syndrome are unknown. We hypothesized that new or persistent right ventricular systolic dysfunction and pulmonary hypertension would be associated with worse patient outcomes.

DESIGN

Retrospective, single-center cohort study.

SETTING

Tertiary care, university-affiliated PICU.

PATIENTS

Children who had at least two echocardiograms less than 8 days following pediatric acute respiratory distress syndrome diagnosis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Between July 1, 2012, and April 30, 2018, 74 children met inclusion criteria. The first echocardiogram was performed a median of 0.61 days (interquartile range, 0.36-0.94 d) and the second echocardiogram was performed a median of 2.57 days (interquartile range, 1.67-3.63 d) after pediatric acute respiratory distress syndrome diagnosis. Univariate analyses showed that new or persistent right ventricular systolic dysfunction as defined by global longitudinal strain or free wall strain was associated with a greater number of ICU days in survivors (global longitudinal strain p = 0.04, free wall strain p = 0.04), lower ventilator-free days at 28 days (global longitudinal strain p = 0.03, free wall strain p = 0.01), and higher rate of PICU death (global longitudinal strain p = 0.046, free wall strain p = 0.01). Mixed-effects multivariate modeling showed that right ventricular global longitudinal strain and right ventricular fractional area change stayed relatively constant over the course of the first 8 days in nonsurvivors and that there was a linear improvement in global longitudinal strain (p = 0.037) and fractional area change (p = 0.05) in survivors. Worsening right ventricular dysfunction at the time of repeat echocardiogram as defined by global longitudinal strain and free wall strain were independently associated with decreased probability of extubation (subdistribution hazard ratio, 0.30 [0.14-0.67]; p = 0.003 and subdistribution hazard ratio, 0.47 [0.23-0.98]; p = 0.043, respectively). In univariate and multivariate analyses, pulmonary hypertension had no significant associations with outcomes in his cohort.

CONCLUSIONS

New or persistent right ventricular systolic dysfunction over the first week following pediatric acute respiratory distress syndrome onset is associated with worse patient outcomes, including decreased probability of extubation and higher PICU mortality.

Early signs of right ventricular systolic and diastolic dysfunction in acute severe respiratory failure: the importance of diastolic restrictive pattern

BACKGROUND

The incidence and pathophysiology of right ventricular failure in patients with severe respiratory insufficiency has been largely investigated. However, there is a lack of early signs suggesting right ventricular systolic and diastolic dysfunction prior to acute cor pulmonale development.

METHODS

We conducted a retrospective analytical cohort study of patients for acute respiratory distress syndrome undertaking an echocardiography during admission in the cardiothoracic intensive care unit. Patients were divided according to treatment: conventional protective ventilation (38 patients, 38%); interventional lung assist (23 patients, 23%); veno-venous extracorporeal membrane oxygenation (37 patients, 37%). Systolic and diastolic function was studied assessing, respectively: right ventricular systolic longitudinal function (tricuspid annular plane systolic excursion) and systolic contraction duration (tricuspid annular plane systolic excursion length); right ventricular diastolic filling time and right ventricular diastolic restrictive pattern (presence of pulmonary valve presystolic ejection wave). Correlation between the respiratory mechanics and systo-diastolic parameters were analysed.

RESULTS

In 98 patients studied, systolic dysfunction (tricuspid annular plane systolic excursion <16 mm) was present in 33.6% while diastolic restrictive pattern was present in 64%. A negative correlation was found between tricuspid annular plane systolic excursion and tricuspid annular plane systolic excursion length (P<0.0001; r -0.42). Tricuspid annular plane systolic excursion and tricuspid annular plane systolic excursion length correlated with right ventricular diastolic filling time (P<0.001; r -0.39). Pulmonary valve presystolic ejection wave was associated with tricuspid annular plane systolic excursion (P<0.0001), tricuspid annular plane systolic excursion length (P<0.0001), right ventricular diastolic filling time (P<0.0001), positive end-expiratory pressure (P<0.0001) and peak inspiratory pressure (P<0.0001).

CONCLUSION

Diastolic restrictive pattern is present in a remarkable percentage of patients with respiratory distress syndrome. Bedside echocardiography allows a mechanistic evaluation of systolic and diastolic interaction of the right ventricle.

Early Right Ventricular Systolic Dysfunction and Pulmonary Hypertension Are Associated With Worse Outcomes in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

The prevalence and importance of early right ventricular dysfunction and pulmonary hypertension in pediatric acute respiratory distress syndrome are unknown. We aimed to describe the prevalence of right ventricular dysfunction and pulmonary hypertension within 24 hours of pediatric acute respiratory distress syndrome diagnosis and their associations with outcomes.

DESIGN

Retrospective, single-center cohort study.

SETTING

Tertiary care, university-affiliated PICU.

PATIENTS

Children who had echocardiograms performed within 24 hours of pediatric acute respiratory distress syndrome diagnosis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Between July 1, 2012, and June 30, 2016, 103 children met inclusion criteria. Echocardiograms were analyzed using established indices of right ventricular and left ventricular systolic function and for evidence of pulmonary hypertension. Echocardiographic abnormalities were common: 26% had low right ventricular fractional area change, 65% had low tricuspid annular plane systolic excursion, 30% had low left ventricular fractional shortening, and 21% had evidence of pulmonary hypertension. Abnormal right ventricular global longitudinal strain and abnormal right ventricular free wall strain were present in 35% and 40% of patients, respectively. No echocardiographic variables differed between or across pediatric acute respiratory distress syndrome severity. In multivariable analyses, right ventricular global longitudinal strain was independently associated with PICU mortality (odds ratio, 3.57 [1.33-9.60]; p = 0.01), whereas right ventricular global longitudinal strain, right ventricular free wall strain, and the presence of pulmonary hypertension were independently associated with lower probability of extubation (subdistribution hazard ratio, 0.46 [0.26-0.83], p = 0.01; subdistribution hazard ratio, 0.58 [0.35-0.98], p = 0.04; and subdistribution hazard ratio, 0.49 [0.26-0.92], p = 0.03, respectively).

CONCLUSIONS

Early ventricular dysfunction and pulmonary hypertension were detectable, prevalent, and independent of lung injury severity in children with pediatric acute respiratory distress syndrome. Right ventricular dysfunction was associated with PICU mortality, whereas right ventricular dysfunction and pulmonary hypertension were associated with lower probability of extubation.

Usefulness of ultrasound in the management of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a life-threatening disease. Different imaging techniques have been used to diagnose and guide the ventilatory management of patients with ARDS. Chest ultrasound is a reliable tool to identify interstitial syndrome, lung consolidation, lung collapse, and pleural effusion. In addition, echocardiography is essential in the diagnosis of diastolic left ventricle dysfunction and the estimation of elevated ventricle filling pressures, which is necessary before diagnosing ARDS. Therefore, combining chest and heart ultrasound assessment is useful to diagnose ARDS and guide the ventilatory management of the disease. Available data in the literature suggest that protocol-based approaches should be implemented for the purposes of diagnosis and management.

Progressive myocardial injury is associated with mortality in the acute respiratory distress syndrome

PURPOSE

Myocardial injury connotes worse prognosis in the Acute Respiratory Distress Syndrome (ARDS), however the prognostic connotation of changes in cardiac troponin (cTn) levels in ARDS patients is not known.

METHODS

We performed a study of 908 ARDS patients enrolled in two previously completed ARDS Network trials. We obtained plasma samples via the NIH BIOLINCC repository and measured cTn using the ARCHITECT STAT high sensitivity troponin-I assay (Abbott Laboratories) at trial day 0 and 3. We constructed Cox proportional hazard models to determine the association between 60-day mortality and quintiles of percentage change in high-sensitivity troponin (ΔhsTnI).

RESULTS

The median percent change in hsTnI (%ΔhsTnI) from day 0 to day 3 was -58.2% (IQR -79.0 to 0%). After multivariable adjustment, participants with a 32.1% or greater increase in hsTnI between day 0 and day 3 (highest quintile) had a 2.27 fold increased risk for mortality (95% CI 1.29 - 3.99, p = 0.002) as well as fewer ventilator-free and ICU-free days compared to the lowest quintile.

CONCLUSION

Progressive myocardial injury in ARDS patients is associated with worse outcome, independent of severity of critical illness. Investigation of the mechanisms underlying this relationship is warranted to guide possible strategies to mitigate myocardial injury in ARDS.

Roles of apoptosis and inflammation in a rat model of acute lung injury induced right ventricular dysfunction

AIM

The effect of intratracheal lipopolysaccharide (LPS) instillation on right ventricular dysfunction in rats was studied with the aim of exploring underlying mechanisms.

MAIN METHODS

A single dose of LPS (10 mg/kg) or an equal volume of saline was instilled intratracheally and lung injury evaluated using histopathologic scoring and wet/dry (W/D) weight ratio at 6 or 12 h post-administration. Besides, serum atrial natriuretic peptide (ANP) was detected using an enzyme-linked immunosorbent assay (ELISA) and right ventricle β-myosin heavy chain (β-MHC) presence was examined using reverse transcription polymerase chain reaction (RT-PCR). Echocardiography examined pulmonary artery acceleration time (PAAT), right ventricular free wall thickness (RVFWT), tricuspid annular plane systolic excursion (TAPSE), and right ventricular end-diastolic diameter (RVEDD). In addition, right ventricular TUNEL staining and Western blots of Bax and Bcl-2 were performed. Right ventricle and left ventricle caspases-3, -8, and -9 activity were examined using fluorometric assay. Finally, right ventricle myeloperoxidase (MPO) neutrophil staining, and right ventricle and plasma cytokines TNF-α, IL-1β, IL-6 detection was performed.

KEY FINDINGS

Histopathologic lung injury and increased W/D weight ratio was seen at 6 h after LPS intratracheal instillation, along with increased ANP, but not β-MHC. Pulmonary hypertension was indicated by decreased PAAT at 6 h post-exposure. Right ventricular systolic dysfunction and dilation were observed at 12 h post-exposure, as indicated by a significant decrease of TAPSE and increase of RVEDD. Of note, the procedure led to an increased right ventricle TUNEL positive cardiomyocytes, an increased Bax/Bcl-2 ratio, and increased right and left ventricle caspases-3, -8, and -9 activity as early as 6 h post-exposure, which was paralleled by increased right ventricle MPO staining and increased expression of right ventricle and serum cytokines TNF-α, IL-1β, and IL-6.

SIGNIFICANCE

As well as acute lung injury, a single dose of LPS intratracheally instilled can induce pulmonary hypertension at 6 h post-exposure, with obvious right ventricular systolic dysfunction and right ventricular dilation present at 12 h post-exposure, possibly via cardiomyocytes apoptosis and inflammation.

Diagnostic value of cardiopulmonary ultrasound in elderly patients with acute respiratory distress syndrome

BACKGROUND

Lung ultrasound and echocardiography are mainly applied in critical care and emergency medicine. However, the diagnostic value of cardiopulmonary ultrasound in elderly patients with acute respiratory distress syndrome (ARDS) is still unclear.

METHODS

Consecutive patients admitted to ICU with the diagnosis of suspected ARDS based on clinical grounds were enrolled. Cardiopulmonary ultrasound was performed as part of monitoring on day 1, day 2 and day 3. On each day a bedside ultrasound was performed to examine the lungs and calculate the Left Ventricular Ejection Fraction (LVEF). On day 3, a thoracic CT was performed on each patient as gold standard for ARDS imaging diagnosis. According to the results from CT scan, patients were grouped into ARDS group or Non-ARDS group. The relation between the cardiopulmonary ultrasound results on each day and the results of CT scan was analyzed.

RESULTS

Fifty one consecutive patients aged from 73 to 97 years old were enrolled. Based on CT criteria, 33 patients were classified into the ARDS group, while 18 patients were included in non-ARDS group. There was no significant difference between the two groups in baseline characteristics, including gender, age, underlying disease, comorbidities, APACHE II score, SOFA score, and PaO2/FiO2 ratio (P > 0.05). Lung ultrasound (LUS) examination results were consistent with the CT scan results in diagnosis of pulmonary lesions. The Kappa values were 0.55, 0.74 and 0.82 on day 1, day 2 and day 3, respectively. The ROC analysis showed that the sensitivity, specificity and area under curve of ROC (AUROC) for lung ultrasound in diagnose ARDS were 0.788,0.778,0.783;0.909,0.833,0.871;0.970,0.833,0.902 on day 1, day 2 and day 3, respectively. However, cardiopulmonary ultrasound performed better in diagnosing ARDS in elderly patients. The sensitivity, specificity and AUROC were 0.879,0.889,0.924;0.939,0.889,0.961;and 0.970,0.833,0.956 on day 1, day 2 and day 3, respectively. The combined performances of cardiopulmonary ultrasound, N-terminal pro-brain natriuretic peptide (NT-proBNP), and PaO2/FiO2 ratio improved the specificity of the diagnosis of ARDS in elderly patients.

CONCLUSIONS

LUS examination results were consistent with the CT scan results in diagnosis of pulmonary lesions. Cardiopulmonary ultrasound has a greater diagnostic accuracy in elderly patients with ARDS, compared with LUS alone. The combined performances of cardiopulmonary ultrasound, NT-proBNP, and PaO₂/FiO₂ increased the specificity of the diagnosis of ARDS in elderly patients.

Acute Right Ventricular Dysfunction in Intensive Care Unit

The role of the left ventricle in ICU patients with circulatory shock has long been considered. However, acute right ventricle (RV) dysfunction causes and aggravates many common critical diseases (acute respiratory distress syndrome, pulmonary embolism, acute myocardial infarction, and postoperative cardiac surgery). Several supportive therapies, including mechanical ventilation and fluid management, can make RV dysfunction worse, potentially exacerbating shock. We briefly review the epidemiology, pathophysiology, diagnosis, and recommendations to guide management of acute RV dysfunction in ICU patients. Our aim is to clarify the complex effects of mechanical ventilation, fluid therapy, vasoactive drug infusions, and other therapies to resuscitate the critical patient optimally.

High uric acid (UA) downregulates bone alkaline phosphatase (BALP) expression through inhibition of its promoter activity

Bone metastases often occur in prostate cancers, lung cancers and breast cancers. Bone alkaline phosphatase (BALP) is one of the most commonly used serological markers for clinical evaluation of bone metabolism. Here, we reported that high concentrations of uric acid (UA) caused decrease of BALP levels and revealed that the effect of high concentrations of UA on the BALP expression was through inhibition of its promoter activity. Our results suggested physicians to think about serum UA status of patients with advanced cancer to avoid misdiagnosis when BALP was used to diagnose or assess the extent of bone metastases.

The Right Ventricle in ARDS

ARDS is associated with poor clinical outcomes, with a pooled mortality rate of approximately 40% despite best standards of care. Current therapeutic strategies are based on improving oxygenation and pulmonary compliance while minimizing ventilator-induced lung injury. It has been demonstrated that relative hypoxemia can be well tolerated, and improvements in oxygenation do not necessarily translate into survival benefit. Cardiac failure, in particular right ventricular dysfunction (RVD), is commonly encountered in moderate to severe ARDS and is reported to be one of the major determinants of mortality. The prevalence rate of echocardiographically evident RVD in ARDS varies across studies, ranging from 22% to 50%. Although there is no definitive causal relationship between RVD and mortality, severe RVD is associated with increased mortality. Factors that can adversely affect RV function include hypoxic pulmonary vasoconstriction, hypercapnia, and invasive ventilation with high driving pressure. It might be expected that early diagnosis of RVD would be of benefit; however, echocardiographic markers (qualitative and quantitative) used to prospectively evaluate the right ventricle in ARDS have not been tested in adequately powered studies. In this review, we examine the prognostic implications and pathophysiology of RVD in ARDS and discuss available diagnostic modalities and treatment options. We aim to identify gaps in knowledge and directions for future research that could potentially improve clinical outcomes in this patient population.