Quantifying systemic congestion with Point-Of-Care ultrasound: development of the venous excess ultrasound grading system

Fluid management in acute kidney injury: from evaluating fluid responsiveness towards assessment of fluid tolerance

Despite the widespread use of intravenous fluids in acute kidney injury (AKI), solid evidence is lacking. Intravenous fluids mainly improve AKI due to true hypovolaemia, which is difficult to discern at the bedside unless it is very pronounced. Empiric fluid resuscitation triggered only by elevated serum creatinine levels or oliguria is frequently misguided, especially in the presence of fluid intolerance syndromes such as increased extravascular lung water, capillary leak, intra-abdominal hypertension, and systemic venous congestion. While fluid responsiveness tests clearly identify patients who will not benefit from fluid administration (i.e. those without an increase in cardiac output), the presence of fluid responsiveness does not guarantee that fluid therapy is indicated or even safe. This review calls for more attention to the concept of fluid tolerance, incorporating it into a practical algorithm with systematic venous Doppler ultrasonography assessment to use at the bedside, thereby lowering the risk of detrimental kidney congestion in AKI.

Hepatic vein Doppler in critically ill patients: a reflection of central venous pressure or right ventricular systolic function?

Background

To explore whether hepatic vein systolic filling fraction (SFF) is associated with central venous pressure (CVP) and right ventricular (RV) systolic function in critically ill patients.

Methods

Adult patients admitted to ICU with echocardiographic examination were retrospectively enrolled. Echocardiographic parameters including hepatic vein systolic velocity (S) and diastolic phase velocity (D) and haemodynamic information at the time of echo examination were collected. RV systolic dysfunction was defined as tricuspid annular plane systolic excursion (TAPSE) < 16 mm. SFF was calculated as S/(S + D).

Results

Two hundred four patients were enrolled in this study among whom 40 patients had a CVP ≤5 mmHg, 110 patients had a CVP 6–9 mmHg and 54 patients had a CVP ≥10 mmHg. The three groups had similar S velocity, D velocity and SFF. No correlation between SFF and CVP was found (r = − 0.046, p = 0.500), but correlation between SFF and TAPSE was noticed (r = 0.468, p < 0.001). The ROC analysis showed that the area under curve (AUC) of SFF for determining CVP ≥10 mmHg was 0.513 (95% CI: 0.420–0.606, p = 0.775), but the AUC of SFF for determining RV systolic dysfunction was 0.759 (95% CI: 0.686–0.833, p < 0.001).

Conclusion

Hepatic vein systolic filling fraction is associated with RV systolic function in critically ill patients and is not associated with CVP.

How to Determine Fluid Management Goals during Continuous Kidney Replacement Therapy in Patients with AKI: Focus on POCUS

The utilization of kidney replacement therapies (KRT) for fluid management of patients who are critically ill has significantly increased over the last years. Clinical studies have suggested that both fluid accumulation and high fluid removal rates are associated with adverse outcomes in the critically ill population receiving KRT. Importantly, the ideal indications and/or fluid management strategies that could favorably affect these patients are unknown; however, differentiating clinical scenarios in which effective fluid removal may provide benefit to the patient by avoiding congestive organ injury, compared with other settings in which this intervention may result in harm, is direly needed in the critical care nephrology field. In this review, we describe observational data related to fluid management with KRT, and examine the role of point-of-care ultrasonography as a potential tool that could provide physiologic insights to better individualize decisions related to fluid management through KRT.

Intrarenal Doppler approaches in hemodynamics: A major application in critical care

The treatment of severe cases usually requires multimodality hemodynamic monitoring approaches, particularly for tissue and organ perfusion tracking. Currently, only a few studies have investigated renal perfusion status at the bedside. Ultrasound has become increasingly utilized to guide the hemodynamic management of severe patients. Similarly, intrarenal Doppler (IRD) is widely used to assess renal perfusion from both the intrarenal artery and vein perspectives. The renal resistive index (RRI), which reflects the renal arterial blood flow profile, is often applied to predict the reversibility of renal dysfunction and to titrate hemodynamic support. Intrarenal venous flow (IRVF) patterns and the renal venous stasis index (RVSI), which reflects the intrarenal vein blood flow profile, are now being used to assess intravenous congestion. They may also be useful in predicting the risk of acute kidney injury and avoiding fluid overload. IRD can provide diverse and supplemental information on renal perfusion and may help to establish the early diagnosis in severe patients. This review focused on the specific operational methods, influencing factors, and applications of IRD in hemodynamics.

Doppler study of portal vein and renal venous velocity predict the appropriate fluid response to diuretic in ICU: a prospective observational echocardiographic evaluation

BACKGROUND

Fluid overload and venous congestion are associated with morbi-mortality in the ICU (intensive care unit). Administration of diuretics to correct the fluid balance is common, although there is no strong relationship between the consequent fluid loss and clinical improvement. The aim of the study was to evaluate the ability of the portal pulsatility index, the renal venous impedance index, and the VEXUS score (venous ultrasound congestion score) to predict appropriate diuretic-induced fluid depletion.

METHODS

The study had a prospective, observational, single-center observational design and was conducted in a university-affiliated medico-surgical ICU. Adult patients for whom the clinician decided to introduce loop diuretic treatment were included. Hemodynamic and ultrasound measurements (including the portal pulsatility index, renal venous impedance index and VEXUS score) were performed at inclusion and 2 hours after the initiation of the diuretics. The patients' characteristics were noted at inclusion, 24 h later, and at ICU discharge. The appropriate diuretic-induced fluid depletion was defined by a congestive score lower than 3 after diuretic fluid depletion. The congestive score included clinical and biological parameters of congestion.

RESULTS

Eighty-one patients were included, and 43 (53%) patients presented with clinically significant congestion score at inclusion. Thirty-four patients (42%) had an appropriate response to diuretic-induced fluid depletion. None of the left- and right-sided echocardiographic parameters differed between the two groups. The baseline portal pulsatility index was the best predictor of appropriate response to diuretic-induced fluid depletion (AUC = 0.80, CI_95%:0.70-0.92, p = 0.001), followed by the renal venous impedance index (AUC = 0.72, CI_95% 0.61-0.84, p = 0.001). The baseline VEXUS score (AUC of 0.66 CI_95% 0.53-0.79, p = 0.012) was poorly predictive of appropriate response to diuretic-induced fluid depletion.

CONCLUSION

The portal pulsatility index and the renal venous impedance index were predictive of the appropriate response to diuretic-induced fluid depletion in ICU patients. The portal pulsatility index should be evaluated in future randomized studies.

How can assessing hemodynamics help to assess volume status?

In critically ill patients, fluid infusion is aimed at increasing cardiac output and tissue perfusion. However, it may contribute to fluid overload which may be harmful. Thus, volume status, risks and potential efficacy of fluid administration and/or removal should be carefully evaluated, and monitoring techniques help for this purpose. Central venous pressure is a marker of right ventricular preload. Very low values indicate hypovolemia, while extremely high values suggest fluid harmfulness. The pulmonary artery catheter enables a comprehensive assessment of the hemodynamic profile and is particularly useful for indicating the risk of pulmonary oedema through the pulmonary artery occlusion pressure. Besides cardiac output and preload, transpulmonary thermodilution measures extravascular lung water, which reflects the extent of lung flooding and assesses the risk of fluid infusion. Echocardiography estimates the volume status through intravascular volumes and pressures. Finally, lung ultrasound estimates lung edema. Guided by these variables, the decision to infuse fluid should first consider specific triggers, such as signs of tissue hypoperfusion. Second, benefits and risks of fluid infusion should be weighted. Thereafter, fluid responsiveness should be assessed. Monitoring techniques help for this purpose, especially by providing real time and precise measurements of cardiac output. When decided, fluid resuscitation should be performed through fluid challenges, the effects of which should be assessed through critical endpoints including cardiac output. This comprehensive evaluation of the risk, benefits and efficacy of fluid infusion helps to individualize fluid management, which should be preferred over a fixed restrictive or liberal strategy.

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 ultrasound in pediatric nephrology

Point-of-care ultrasound (POCUS) has evolved in recent years in clinical practice, helping in early bedside diagnosis of important etiologies. Many medical schools and training programs are integrating POCUS into their curriculum. Especially with the technological advances of newer handheld ultrasound devices, POCUS has now become a component adjunct to clinical examination, in the clinic and bedside in critical care units. The diagnostic utility of POCUS lies both in early identification of critical kidney disease, and also extra-renal pathologies from a focused cardiac ultrasound, lung ultrasound, and integrated fluid assessment. There is a need to incorporate POCUS in training in pediatric nephrology and establish competency standard criteria. This review shall cover how POCUS helps in enhancing patient care in pediatric kidney disorders and critical children, and the recent advances.

The Kidney in Heart Failure: The Role of Venous Congestion

Heart failure can lead to renal impairment, an interaction now termed "cardiorenal syndrome." The prevalent physiological explanation for the renal impairment that accompanies heart failure centers around the forward failure hypothesis, which emphasizes the role of left ventricular dysfunction in causing edema, and the backward failure hypothesis, which singles out venous congestion as the dominant mechanism of edema and reduced glomerular filtration rate. In this review, we provide an appraisal on venous congestion, an extremely important contributor that has received little attention. We also summarize the pharmacology of loop diuretics, explain current understanding of diuretic resistance, and address controversies regarding decongestive treatments.

Decreased renal cortical perfusion, independent of changes in renal blood flow and sublingual microcirculatory impairment, is associated with the severity of acute kidney injury in patients with septic shock

Background

Reduced renal perfusion has been implicated in the development of septic AKI. However, the relative contributions of macro- and microcirculatory blood flow and the extent to which impaired perfusion is an intrinsic renal phenomenon or part of a wider systemic shock state remains unclear.

Methods

Single-centre prospective longitudinal observational study was carried out. Assessments were made at Day 0, 1, 2 and 4 after ICU admission of renal cortical perfusion in 50 patients with septic shock and ten healthy volunteers using contrast-enhanced ultrasound (CEUS). Contemporaneous measurements were made using transthoracic echocardiography of cardiac output. Renal artery blood flow was calculated using velocity time integral and vessel diameter. Assessment of the sublingual microcirculation was made using handheld video microscopy. Patients were classified based on the degree of AKI: severe = KDIGO 3 v non-severe = KDIGO 0–2.

Results

At study enrolment, patients with severe AKI (37/50) had prolonged CEUS mean transit time (mTT) (10.2 vs. 5.5 s, p < 0.05), and reduced wash-in rate (WiR) (409 vs. 1203 au, p < 0.05) and perfusion index (PI) (485 vs. 1758 au, p < 0.05); differences persisted throughout the entire study. Conversely, there were no differences in either cardiac index, renal blood flow or renal resistive index. Sublingual microcirculatory variables were not significantly different between groups at study enrolment or at any subsequent time point. Although lactate was higher in the severe AKI group at study enrolment, these differences did not persist, and there were no differences in either ScvO2 or ScvCO2-SaCO2 between groups. Patients with severe AKI received higher doses of noradrenaline (0.34 vs. 0.21mcg/kg/min, p < 0.05). Linear regression analysis showed no correlation between mTT and cardiac index (R-0.18) or microcirculatory flow index (R-0.16).

Conclusion

Renal cortical hypoperfusion is a persistent feature in critically ill septic patients who develop AKI and does not appear to be caused by reductions in macrovascular renal blood flow or cardiac output. Cortical hypoperfusion appears not be associated with changes in the sublingual microcirculation, raising the possibility of a specific renal pathogenesis that may be amenable to therapeutic intervention.

Trial Registration Clinical Trials.gov NCT03713307, 19 Oct 2018.

Point-of-Care Ultrasound in the Intensive Care Unit: Applications, Limitations, and the Evolution of Clinical Practice

The use of point-of-care ultrasonography in the intensive care unit has been rapidly advancing over the past 20 years. This review will provide a broad overview of the discipline spanning lung ultrasonography to advanced critical care echocardiography. It will highlight new research that questions the utility of the inferior vena cava for determining volume responsiveness and will introduce the reader to cutting-edge technology including artificial intelligence, which is likely to revolutionize ultrasound teaching and image interpretation, increasing the reach of this modality for the frontline clinician.

Management of the Critically Ill Patient with Pulmonary Arterial Hypertension and Right Heart Failure

Right ventricular (RV) failure is a recognized complication of pulmonary hypertension (PH). Pregnancy and surgery represent unique challenges to the patient with PH and require input from an interprofessional team. Approach to treatment must embrace sound physiologic principles that are based on optimization of RV preload, contractility, and afterload to improve cardiac function and tissue perfusion before the onset of multiorgan dysfunction. Failure of medical therapy needs to be recognized before the onset of irreversible shock. When appropriate, eligible patients should be considered for mechanical circulatory support as a bridge to recovery or transplantation.

Multimodal Strategies for the Diagnosis and Management of Refractory Congestion. An Integrated Cardiorenal Approach

Refractory congestion is common in acute and chronic heart failure, and it significantly impacts functional class, renal function, hospital admissions, and survival. In this paper, the pathophysiological mechanisms involved in cardiorenal syndrome and the interplay between heart failure and chronic kidney disease are reviewed. Although the physical exam remains key in identifying congestion, new tools such as biomarkers or lung, vascular, and renal ultrasound are currently being used to detect subclinical forms and can potentially impact its management. Thus, an integrated multimodal diagnostic algorithm is proposed. There are several strategies for treating congestion, although data on their efficacy are scarce and have not been validated. Herein, we review the optimal use and monitorization of different diuretic types, administration route, dose titration using urinary volume and natriuresis, and a sequential diuretic scheme to achieve a multitargeted nephron blockade, common adverse events, and how to manage them. In addition, we discuss alternative strategies such as subcutaneous furosemide, hypertonic saline, and albumin infusions and the available evidence of their role in congestion management. We also discuss the use of extracorporeal therapies, such as ultrafiltration, peritoneal dialysis, or conventional hemodialysis, in patients with normal or impaired renal function. This review results from a multidisciplinary view involving both nephrologists and cardiologists.

New Insights Into Diuretic Use to Treat Congestion in the ICU: Beyond Furosemide

Diuretics are commonly used in critically ill patients with acute kidney injury (AKI) and fluid overload in intensive care units (ICU), furosemide being the diuretic of choice in more than 90% of the cases. Current evidence shows that other diuretics with distinct mechanisms of action could be used with good results in patients with selected profiles. From acetazolamide to tolvaptan, we will discuss recent studies and highlight how specific diuretic mechanisms could help to manage different ICU problems, such as loop diuretic resistance, hypernatremia, hyponatremia, or metabolic alkalosis. The current review tries to shed some light on the potential use of non-loop diuretics based on patient profile and give recommendations for loop diuretic treatment performance focused on what the intensivist and critical care nephrologist need to know based on the current evidence.

New developments in the understanding of right ventricular function in acute care

PURPOSE OF REVIEW

Right ventricular dysfunction has an important impact on the perioperative course of cardiac surgery patients. Recent advances in the detection and monitoring of perioperative right ventricular dysfunction will be reviewed here.

RECENT FINDINGS

The incidence of right ventricular dysfunction in cardiac surgery has been associated with unfavorable outcomes. New evidence supports the use of a pulmonary artery catheter in cardiogenic shock. The possibility to directly measure right ventricular pressure by transducing the pacing port has expanded its use to track changes in right ventricular function and to detect right ventricular outflow tract obstruction. The potential role of myocardial deformation imaging has been raised to detect patients at risk of postoperative complications.

SUMMARY

Perioperative right ventricular function monitoring is based on echocardiographic and extra-cardiac flow evaluation. In addition to imaging modalities, hemodynamic evaluation using various types of pulmonary artery catheters can be achieved to track changes rapidly and quantitatively in right ventricular function perioperatively. These monitoring techniques can be applied during and after surgery to increase the detection rate of right ventricular dysfunction. All this to improve the treatment of patients presenting early signs of right ventricular dysfunction before systemic organ dysfunction ensue.

Venous Excess Doppler Ultrasound for the Nephrologist: Pearls and Pitfalls

The role of venous congestion in abnormal kidney function is being increasingly recognized. It is well known that unresolved congestion is associated with adverse kidney and overall outcomes in patients with heart failure. Similarly, any condition that leads to elevated central venous pressure, such as pulmonary hypertension, can result in impaired kidney perfusion by increasing its afterload. Point-of-care ultrasonography (POCUS) enables the clinician to objectively assess hemodynamics at the bedside and, thereby, guide patient management. Lung POCUS has received widespread attention in the recent past because of the relative ease of the technique, but it reflects only left heart pressures and not venous congestion. Although inferior vena cava POCUS is used to estimate right atrial pressure, its isolated use cannot demonstrate organ congestion. Moreover, it is associated with several technical and conceptual limitations. Recently, venous excess Doppler ultrasound has emerged as a tool to assess venous congestion at the organ level in real time. Severe flow abnormalities in hepatic, portal, and kidney parenchymal veins have shown to predict the risk of congestive kidney injury. In addition, it helps to objectively monitor the efficacy of decongestive therapy. In this review, we provide a brief overview of various components of venous excess Doppler ultrasound and share our perspective on incorporating this novel tool in nephrology practice.

Portal Vein Pulsatility Index as a Potential Risk of Venous Congestion Assessed by Magnetic Resonance Imaging: A Prospective Study on Healthy Volunteers

High values of the portal vein pulsatility index (PI) have been associated with adverse outcomes in perioperative or critically ill patients. However, data on dynamic changes of PI related to fluid infusion are scarce. We aimed to determine if dynamic changes in PI are associated with the fluid challenge (FC). To address this challenge, we conducted a prospective single-center study. The population study included healthy subjects. FC consisted in the administration of 500 ml of Ringer lactate infusion over 5 min. The portal blood flow and PI were assessed by magnetic resonance imaging. The responsiveness to FC was defined as an increase in the cardiac stroke volume of at least 10% as assessed by echocardiography. We included 24 healthy volunteers. A total of fourteen (58%) subjects were responders, and 10 (42%) were non-responders. In the responder group, FC induced a significant increase in portal blood flow from 881 (762–1,001) at the baseline to 1,010 (778–1,106) ml min⁻¹ (p = 0.005), whilst PI remained stable (from 31 [25–41] to 35 (25–42) %; p = 0.12). In the non-responder group, portal blood flow remained stable after FC (from 1,042 to 1,034 ml min⁻¹; p = 0.084), whereas PI significantly increased from 32 (22–40) to 48% *(25–85) after FC (p = 0.027). PI was negatively correlated to portal blood flow (Rho coefficient = −0.611; p = 0.002). To conclude, PI might be a sensitive marker of early congestion in healthy subjects that did not respond to FC. This finding requires further validation in clinical settings with a larger sample size.

Airway Pressure Release Ventilation With Time-Controlled Adaptive Ventilation (TCAV™) in COVID-19: A Community Hospital's Experience

Santa Cabrini Ospedale, a community hospital in Montreal, Canada, used the airway pressure release ventilation following a time-controlled adaptive ventilation (APRV-TCAV™) approach for several patients in the first wave of the coronavirus disease 2019 (COVID-19) outbreak in the spring of 2021. Based on favorable patient responses, it became the primary mode of invasive mechanical ventilation—from initiation through extubation—during the second and third waves of COVID-19. In this article, we describe our success with APRV-TCAV™ over more conventional modes and protocols and look at three cases that aptly demonstrate our experience. We then outline several risks with our approach and the lessons learned from our experience. While we generally saw improvement in patients’ clinical course with APRV-TCAV™, there are inherent risks with this approach that others must prepare for if they attempt to implement it in their practice.

[Targeted hemodynamic monitoring in the operating theatre: what for and by what means?]

Goal directed hemodynamic monitoring and the balance in goal directed therapy between adequate fluid/volume therapy and the application of vasoactive or inotropic drugs are the basic elements of modern perioperative therapy.Surgical procedures should be accompanied by as few side effects and complications as possible. Nevertheless, the number of postoperative complications remains surprisingly high, despite of the modern surgical procedures. Anticipation of potential complications in the perioperative period and their rapid treatment build a core competence of anesthesiological action. Thus, it is clear that anesthesia plays a central role in this balancing act.This article aims to provide an overview of the application of the currently available perioperative goal directed hemodynamic monitoring. The current possibilities are discussed by using a case example and an outlook on the future of hemodynamic monitoring is given.

Non-Invasive Assessment of Congestion by Cardiovascular and Pulmonary Ultrasound and Biomarkers in Heart Failure

Worsening chronic heart failure (HF) is responsible for recurrent hospitalization and increased mortality risk after discharge, irrespective to the ejection fraction. Symptoms and signs of pulmonary and systemic congestion are the most common cause for hospitalization of acute decompensated HF, as a consequence of increased cardiac filling pressures. The elevated cardiac filling pressures, also called hemodynamic congestion, may precede the occurrence of clinical congestion by days or weeks. Since HF patients often have comorbidities, dyspnoea, the main symptom of HF, may be also caused by respiratory or other illnesses. Recent studies underline the importance of the diagnosis and treatment of hemodynamic congestion before HF symptoms worsen, reducing hospitalization and improving prognosis. In this paper we review the role of integrated evaluation of biomarkers and imaging technics, i.e., echocardiography and pulmonary ultrasound, for the diagnosis, prognosis and treatment of congestion in HF patients.

Cardiorenal syndrome: classification, pathophysiology, diagnosis and management. Literature review

The cardiorenal syndrome is a complex entity in which a primary heart dysfunction causes kidney injury (Types 1 and 2) and vice versa (Types 3 and 4), being either acute or chronic events, or maybe the result of a systemic disease that involves both organs (Type 5). Approximately 49% of heart failure cases present some grade of kidney dysfunction, significantly increasing morbidity and mortality rates. Its pathogenesis involves a variety of hemodynamic, hormonal and immunological factors that in the majority of cases produce fluid overload; the diagnosis and treatment of such constitutes the disease’s management basis. Currently, a clinical based diagnosis is insufficient and the use of biochemical markers, such as natriuretic peptides, or lung and heart ultrasound is required. These tools, along with urinary sodium levels, allow the evaluation of therapy effectiveness. The preferred initial decongestive strategy is based on a continuous infusion of a loop diuretic with a step-up dosing regimen, aiming for a minimal daily urine volume of 3 liters, with the possibility to sequentially add potassium sparing diuretics, thiazide diuretics and carbonic anhydrase inhibitors to reach the diuresis goal, leaving ultrafiltration as a last resource due to its higher rate of complications. Finally, evidence-based therapy should be given to improve quality of life, decrease mortality, and delay the deterioration of kidney and heart function over the long term.

The Intensivist's Perspective of Shock, Volume Management, and Hemodynamic Monitoring

One of the primary reasons for intensive care admission is shock. Identifying the underlying cause of shock (hypovolemic, distributive, cardiogenic, and obstructive) may lead to entirely different clinical pathways for management. Among patients with hypovolemic and distributive shock, fluid therapy is one of the leading management strategies. Although an appropriate amount of fluid administration might save a patient's life, inadequate (or excessive) fluid use could lead to more complications, including organ failure and mortality due to either hypovolemia or volume overload. Currently, intensivists have access to a wide variety of information sources and tools to monitor the underlying hemodynamic status, including medical history, physical examination, and specific hemodynamic monitoring devices. Although appropriate and timely assessment and interpretation of this information can promote adequate fluid resuscitation, misinterpretation of these data can also lead to additional mortality and morbidity. This article provides a narrative review of the most commonly used hemodynamic monitoring approaches to assessing fluid responsiveness and fluid tolerance. In addition, we describe the benefits and disadvantages of these tools.

Hospital at home for acute medical illness: The 21st century acute medical unit for a changing population

Recent trends across Europe show a year-on-year increase in the number of patients with acute medical illnesses presenting to hospitals, yet there are no plans for a substantial expansion in acute hospital infrastructure or staffing to address demand. Strategies to meet increasing demand need to consider the fact that there is limited capacity in acute hospitals and focus on new care models in both hospital and community settings. Increasing the efficiency of acute hospital provision by reducing the length of stay entails supporting acute ambulatory care, where patients receive daily acute care interventions but do not stay overnight in the hospitals. This approach may entail daily transfer between home and an acute setting for ongoing treatment, which is unsuitable for some patients living with frailty. Acute hospital at home (HaH) is a care model which, thanks to advances in point of care diagnostic capability, can provide a credible model of acute medical assessment and treatment without the need for hospital transfer. Investment and training to support scaling up of HaH are key strategic aims for integrated healthcare systems.

Characteristic Immune Dynamics in COVID-19 Patients with Cardiac Dysfunction

Background: We aimed to explore immune parameters in COVID-19 patients admitted to the intensive care unit (ICU) to identify distinctive features in patients with cardiac injury. Methods: A total of 30 COVID-19 patients >18 years admitted to the ICU were studied on days D1, D3 and D7 after admission. Cardiac function was assessed using speckle-tracking echocardiography (STE). Peripheral blood immunophenotyping, cardiac (pro-BNP; troponin) and inflammatory biomarkers were simultaneously evaluated. Results: Cardiac dysfunction (DYS) was detected by STE in 73% of patients: 40% left ventricle (LV) systolic dysfunction, 60% LV diastolic dysfunction, 37% right ventricle systolic dysfunction. High-sensitivity cardiac troponin (hs-cTn) was detectable in 43.3% of the patients with a median value of 13.00 ng/L. There were no significant differences between DYS and nDYS patients regarding mortality, organ dysfunction, cardiac (including hs-cTn) or inflammatory biomarkers. Patients with DYS showed persistently lower lymphocyte counts (median 896 [661−1837] cells/µL vs. 2141 [924−3306] cells/µL, p = 0.058), activated CD3 (median 85 [66−170] cells/µL vs. 186 [142−259] cells/µL, p = 0.047) and CD4 T cells (median 33 [28−40] cells/µL vs. 63 [48−79] cells/µL, p = 0.005), and higher effector memory T cells (TEM) at baseline (CD4%: 10.9 [6.4−19.2] vs. 5.9 [4.2−12.8], p = 0.025; CD8%: 15.7 [7.9−22.8] vs. 8.1 [7.7−13.7], p = 0.035; CD8 counts: 40 cells/µL [17−61] vs. 10 cells/µL [7−17], p = 0.011) than patients without cardiac dysfunction. Conclusion: Our study suggests an association between the immunological trait and cardiac dysfunction in severe COVID-19 patients.

Association between Preoperative Retrograde Hepatic Vein Flow and Acute Kidney Injury after Cardiac Surgery

Key questions: Is there a predictive value of hepatic venous flow patterns for postoperative acute kidney injury (AKI) after cardiac surgery? Key findings: In patients who underwent cardiac surgery, retrograde hepatic venous waves (A, V) and their respective ratio to anterograde waves showed a strong association with postoperative AKI, defined as the percentage change of the highest postoperative serum creatinine from the baseline preoperative concentration (%ΔCr). The velocity time integral (VTI) of the retrograde A wave and the ratio of the retrograde and anterograde waves’ VTI were independently associated with AKI after adjustment for disease severity. Take-home message: A higher ratio of retrograde/antegrade waves in hepatic venous retrograde waves, which are related to hepatic stasis, may predict AKI after cardiac surgery. Introduction: Hepatic venous flow patterns reflect pressure changes in the right ventricle and are also markers of systemic venous congestion. Pulsatility of the inferior caval vein was used to predict the risk of acute kidney injury (AKI) after cardiac surgery. Aims: Our objective was to evaluate the association between preoperative hepatic venous flow patterns and the risk of AKI in patients after cardiac surgery. Methods: This prospective, observational study included 98 patients without preexisting liver disease who underwent cardiac surgery between 1 January 2018, and 31 March 2020, at a tertiary heart center. In addition to a routine echocardiographic examination, we recorded the maximal velocity and velocity time integral (VTI) of the standard four waves in the common hepatic vein with Doppler ultrasound. Our primary outcome measure was postoperative AKI, defined as the percentage change of the highest postoperative serum creatinine from the baseline preoperative concentration (%ΔCr). The secondary outcome was AKI, defined by KDIGO (Kidney Disease Improving Global Outcomes) criteria. Results: The median age of the patients was 69.8 years (interquartile range [IQR 25−75] 13 years). Seventeen patients (17.3%) developed postoperative AKI based on the KDIGO. The VTI of the retrograde A waves in the hepatic veins showed a strong correlation (B: 0.714; p = 0.0001) with an increase in creatinine levels after cardiac surgery. The velocity time integral (VTI) of the A wave (B = 0.038, 95% CI = 0.025−0.051, p < 0.001) and the ratio of VTI of the retrograde and anterograde waves (B = 0.233, 95% CI = 0.112−0.356, p < 0.001) were independently associated with an increase in creatinine levels. Conclusions: The severity of hepatic venous regurgitation can be a sign of venous congestion and seems to be related to the development of AKI.

Point-of-care ultrasound for critically-ill patients: A mini-review of key diagnostic features and protocols

Point-of-care ultrasonography (POCUS) for managing critically ill patients is increasingly performed by intensivists or emergency physicians. Results of needs surveys among intensivists reveal emphasis on basic cardiac, lung and abdominal ultrasound, which are the commonest POCUS modalities in the intensive care unit. We therefore aim to describe the key diagnostic features of basic cardiac, lung and abdominal ultrasound as practised by intensivists or emergency physicians in terms of accuracy (sensitivity, specificity), clinical utility and limitations. We also aim to explore POCUS protocols that integrate basic cardiac, lung and abdominal ultrasound, and highlight areas for future research.

Water - A life-giving toxin - A nephrological oxymoron. Health consequences of water and sodium balance disorders. A review article

BACKGROUND

This article aims to reveal misconceptions about methods of assessment of hydration status and impact of the water disorders on the progression of kidney disease or renal dysfunction.

MATERIALS AND METHODS

The PubMed database was searched for reviews, meta-analyses and original articles on hydration, volume depletion, fluid overload and diagnostic methods of hydration status, which were published in English.

RESULTS

Based on the results of available literature the relationship between the amount of fluid consumed, and the rate of progression of chronic kidney disease, autosomal dominant polycystic kidney disease, and kidney stones disease was discussed. Selected aspects of the assessment of the hydration level in clinical practice based on physical examination, laboratory tests, and imaging are presented. The subject of in-hospital fluid therapy is discussed. Based on available randomized studies, an attempt was made to assess, which fluids should be selected for intravenous treatment.

CONCLUSIONS

There is some evidence for the beneficial effect of increased water intake in preventing recurrent cystitis and kidney stones, but there are still no convincing data for chronic kidney disease and autosomal dominant polycystic kidney disease. Further studies are needed to clarify the aforementioned issues and establish a reliable way to assess the volemia and perform suitable fluid therapy.

Assessing Fluid Intolerance with Doppler Ultrasonography: A Physiological Framework

Ultrasonography is becoming the favored hemodynamic monitoring utensil of emergentologists, anesthesiologists and intensivists. While the roles of ultrasound grow and evolve, many clinical applications of ultrasound stem from qualitative, image-based protocols, especially for diagnosing and managing circulatory failure. Often, these algorithms imply or suggest treatment. For example, intravenous fluids are opted for or against based upon ultrasonographic signs of preload and estimation of the left ventricular ejection fraction. Though appealing, image-based algorithms skirt some foundational tenets of cardiac physiology; namely, (1) the relationship between cardiac filling and stroke volume varies considerably in the critically ill, (2) the correlation between cardiac filling and total vascular volume is poor and (3) the ejection fraction is not purely an appraisal of cardiac function but rather a measure of coupling between the ventricle and the arterial load. Therefore, management decisions could be enhanced by quantitative approaches, enabled by Doppler ultrasonography. Both fluid ‘responsiveness’ and ‘tolerance’ are evaluated by Doppler ultrasound, but the physiological relationship between these constructs is nebulous. Accordingly, it is argued that the link between them is founded upon the Frank–Starling–Sarnoff relationship and that this framework helps direct future ultrasound protocols, explains seemingly discordant findings and steers new routes of enquiry.

Use of Venous Excess UltraSound (VExUS) score in hyponatraemia management in critically ill patient

Hyponatraemia is the most prevalent electrolyte disorder in the neurocritical care setting and is associated with a significant morbimortality. Cerebral salt wasting and inappropriate antidiuretic hormone secretion syndrome have been classically described as the two most frequent entities responsible for hyponatraemia in neurocritical care patients. An accurate aetiological diagnosis of hypotonic hyponatraemia requires a proper volume status assessment. Nevertheless, determination of volume status based on physical examination, laboratory findings and imaging modalities have several limitations and can lead to improperly diagnosis and hyponatraemia mismanagement. Point-of-care ultrasound (POCUS), specifically Venous Excess UltraSound (VExUS) score, is a fast and valuable tool to evaluate venous congestion at the bedside and identify hypervolaemia, helping the physicians in therapeutic decision making in a patient with hyponatraemia. We report a case where the use of POCUS, and more specifically VExUS, can be helpful in volume status assessment, complementing the complex management of multifactorial hyponatraemia in a neurocritical patient.

POCUS in Intensive Care Nephrology

Acute kidney injury (AKI) is a significant problem for patients admitted to the intensive care unit (ICU), both due to the high incidence and associated mortality with rates of AKI requiring renal replacement therapy (RRT) of over 5%, and mortality rates with AKI of over 60% 1, 2.Ultrasound can be used to identify those at risk for AKI and assist with AKI management. Risk factors for AKI in the ICU not only include hypoperfusion but also venous congestion and volume overload. Volume overload and vascular congestion are associated with multi-organ dysfunction and worse renal outcomes. Daily and overall fluid balance, daily weights, and physical examination for edema can be inaccurate and belie true systemic venous pressure 3, 4, 5. Bedside ultrasound allows providers to evaluate vascular flow patterns and obtain a more reliable evaluation of volume status to guide and individualize therapies. Cardiac, lung, and vascular patterns on ultrasound can identify preload responsiveness, which should be assessed to safely manage ongoing fluid resuscitation and assess for signs of fluid intolerance. Here we present an overview in the use of point of care ultrasound with particular emphasis on nephro-centric strategies, namely in the identification of the type of renal injury, renal vascular flow assessment, the static measure of volume status, as well as dynamic evaluation for volume optimization in critically ill patients.

Nephrologist-performed portal vein Doppler to monitor response to diuretic therapy

Conventional parameters for assessment of fluid status suffer from several limitations. IVC maybe chronically dilated in patients with pulmonary hypertension. Portal vein Doppler offers an additional data point to assess the severity of venous congestion as well as monitor the efficacy of decongestive therapy.

Medical management of acute heart failure

Despite recent advances in the treatment of chronic heart failure, therapeutic options for acute heart failure (AHF) remain limited. AHF admissions are associated with significant multi-organ dysfunction, especially worsening renal failure, which results in significant morbidity and mortality. There are several aspects of AHF management: diagnosis, decongestion, vasoactive therapy, goal-directed medical therapy initiation and safe transition of care. Effective diagnosis and prognostication could be very helpful in an acute setting and rely upon biomarker evaluation with noninvasive assessment of fluid status. Decongestive strategies could be tailored to include pharmaceutical options along with consideration of utilizing ultrafiltration for refractory hypervolemia. Vasoactive agents to augment cardiac function have been evaluated in patients with AHF but have shown to only have limited efficacy. Post stabilization, initiation of quadruple goal-directed medical therapy—angiotensin receptor-neprilysin inhibitors, mineral receptor antagonists, sodium glucose type 2 (SGLT-2) inhibitors, and beta blockers—to prevent myocardial remodeling is being advocated as a standard of care. Safe transition of care is needed prior to discharge to prevent heart failure rehospitalization and mortality. Post-discharge close ambulatory monitoring (including remote hemodynamic monitoring), virtual visits, and rehabilitation are some of the strategies to consider. We hereby review the contemporary approach in AHF diagnosis and management.

Usefulness of Serial Multiorgan Point-of-Care Ultrasound in Acute Heart Failure: Results from a Prospective Observational Cohort

Background and Objectives: Acute heart failure (AHF) is a common disease and a cause of high morbidity and mortality, constituting a major health problem. The main purpose of this study was to determine the impact of multiorgan ultrasound in identifying pulmonary hypertension (PH), a major prognostic factor in patients admitted due to AHF, and assess whether there are significant changes in the venous excess ultrasonography (VE × US) score or femoral vein Doppler at discharge. Materials and Methods: Patients were evaluated with a standard protocol of lung ultrasound, echocardiography, inferior vena cava (IVC) and hepatic, portal, intra-renal and femoral vein Doppler flow patterns at admission and on the day of discharge. Results: Thirty patients were enrolled during November 2021. The mean age was seventy-nine years (Standard Deviation-SD 13.4). Seven patients (23.3%) had a worsening renal function during hospitalization. Regarding ultrasound findings, VE × US score was calculated at admission and at discharge, unexpectedly remaining unchanged or even worsened (21 patients, 70.0%). The area under the curve for the lung score was 83.9% (p = 0.008), obtaining a cutoff value of 10 that showed a sensitivity of 82.6% and a specificity of 71.4% in the identification of intermediate and high PH. It was possible to monitor significant changes between both exams on the lung score (16.5 vs. 9.3; p < 0.001), improvement in the hepatic vein Doppler pattern (2.4 vs. 2.1; p = 0.002), improvement in portal vein Doppler pattern (1.7 vs. 1.4; p = 0.023), without significant changes in the intra-renal vein Doppler pattern (1.70 vs. 1.57; p = 0.293), VE × US score (1.3 vs. 1.1; p = 0.501), femoral vein Doppler pattern (2.4 vs. 2.1; p = 0.161) and IVC collapsibility (2.0 vs. 2.1; p = 0.420). Conclusions: Our study results suggest that performing serial multiorgan Point-of-Care ultrasound can help us to better identify high and intermediate probability of PH patients with AHF. Currently proposed multi-organ, venous Doppler scanning protocols, such as the VE × US score, should be further studied before expanding its use in AHF patients.

Bedside Assessment of the Kidneys and Bladder Using Point of Care Ultrasound

Given the contrasting echogenic characteristics of the urinary system and their easily identifiable distortion in response to numerous pathologic processes, the sonographic examination of the kidney and bladder can provide a wealth of clinical information [1, 2]. Although performed for decades as a referral and comprehensive radiologic study, improvement in the cost and performance of portable ultrasound devices has now made point of care ultrasound (POCUS) accessible to a growing number and variety of healthcare providers. The purpose of this review is to describe the technique and benefits of using POCUS to evaluate the kidneys, ureters, and bladder in common clinical scenarios.

Evaluation of Venous Congestion Using Beside Ultrasonography by the Nephrology Consultant: The VExUS Nexus

In patients with heart failure and cardiorenal syndrome, lingering congestion is associated with worse outcomes. As such, titrating diuretic or ultrafiltration therapy based on objective assessment of volume status plays a crucial role in the management of these patients. Conventional physical examination findings and parameters such as daily weight measurement are not always reliable in this setting. Recently, point of care ultrasonography (POCUS) has emerged as an attractive enhancement to bedside clinical examination in assessing fluid volume status. Specifically, Doppler ultrasound of the major abdominal veins gives additional information about end-organ congestion when used in conjunction with inferior vena cava ultrasound. Moreover, these Doppler waveforms can be monitored in real time to gauge the efficacy of decongestive therapy. Herein, we present a case that illustrates the utility of POCUS in the management of a patient with heart failure exacerbation.

Perioperative Venous Excess Ultrasound Score (VExUS) to Guide Decongestion in a Dilated Cardiomyopathy Patient Presenting for Urgent Surgery

Venous excess ultrasound score (VExUS) is a recently described ultrasound-based scoring system that quantifies systemic congestion using Doppler flow indices of the hepatic and portal vein in addition to inferior vena cava assessment. There are many potential and emerging applications of this modality. We discuss the case of a severely congested heart failure patient presenting for urgent non-cardiac surgery where VExUS parameters were used to monitor and guide his decongestive therapy postoperatively.

Characteristics and Outcomes for Low-Risk Hospital Admissions Admitted to the ICU: A Multisite Cohort Study

Supplemental Digital Content is available in the text.

IMPORTANCE:

Prognostication following ICU admission can often be determined based on known risk factors, including demographics and illness severity; however, little is known about outcomes of patients deemed to be “low-risk” at the time of hospital admission who subsequently are admitted to the ICU.

OBJECTIVES:

The objectives of this study were to determine the characteristics, outcomes, and costs for patients requiring ICU admission despite having lower predicted mortality when they were admitted to the hospital.

DESIGN, SETTING, AND PARTICIPANTS:

In this historical cohort study, we used a prospectively maintained ICU registry that included all ICU admissions to The Ottawa Hospital for patients 18 years or older from January 2011 to December 2016. We classified patients as low-risk using the Hospital-patient 1-year Mortality Risk at admission score, a hospital admission score validated to predict 1-year mortality.

MAIN OUTCOMES AND MEASURES:

The primary outcome was inhospital mortality. Secondary outcomes included adverse events, resource utilization, and costs.

RESULTS:

Of the 17,173 total ICU patients, 3,445 (20.1%) were classified as low-risk at hospital admission. Low-risk patients were younger (48.7 vs 67.5 yr; p < 0.001) and had a lower Multiple Organ Dysfunction Score (2.37 vs 4.14; p < 0.001). Mortality for low-risk patients was significantly lower than for non–low-risk patients (4.1% vs 25.4%; p < 0.001). For low-risk patients, multivariable logistic regression showed mortality was independently associated with older age (odds ratio, 1.02 per 1 yr; 95% CI, 1.00–1.03 per 1 yr), Multiple Organ Dysfunction Score (odds ratio, 1.42 per 1 point; 95% CI, 1.31–1.54 per 1 point), fluid management adverse events (odds ratio, 2.84; 95% CI, 1.29–6.25), hospital-acquired infections (odds ratio, 1.60; 95% CI, 1.02–2.51), and mechanical ventilation (odds ratio, 1.98; 95% CI, 1.20–3.26).

CONCLUSIONS AND RELEVANCE:

Despite their robust premorbid status, low-risk patients admitted to the ICU had significant inhospital mortality. Fluid management adverse events, hospital-associated infections, multiple organ dysfunction, and mechanical ventilation are important prognostic factors for low-risk patients.

Portal Vein Pulsatility as a Dynamic Marker of Venous Congestion Following Cardiac Surgery: An Interventional Study Using Positive End-Expiratory Pressure

We aimed to assess variations in the portal vein pulsatility index (PI) during mechanical ventilation following cardiac surgery. Method. After ethical approval, we conducted a prospective monocentric study at Amiens University Hospital. Patients under mechanical ventilation following cardiac surgery were enrolled. Doppler evaluation of the portal vein (PV) was performed by transthoracic echography. The maximum velocity (VMAX) and minimum velocity (VMIN) of the PV were measured in pulsed Doppler mode. The PI was calculated using the following formula (VMAX − VMIN)/(VMax). A positive end-expiratory pressure (PEEP) incremental trial was performed from 0 to 15 cmH₂O, with increments of 5 cmH₂O. The PI (%) was assessed at baseline and PEEP 5, 10, and 15 cmH₂O. Echocardiographic and hemodynamic parameters were recorded. Results. In total, 144 patients were screened from February 2018 to March 2019 and 29 were enrolled. Central venous pressure significantly increased for each PEEP increment. Stroke volumes were significantly lower after PEEP incrementation, with 52 mL (50–55) at PEEP 0 cmH₂O and 30 mL (25–45) at PEEP 15 cmH₂O, (p < 0.0001). The PI significantly increased with PEEP incrementation, from 9% (5–15) at PEEP 0 cmH₂O to 15% (5–22) at PEEP 5 cmH₂O, 34% (23–44) at PEEP 10 cmH₂O, and 45% (25–49) at PEEP 15 cmH₂O (p < 0.001). Conclusion. In the present study, PI appears to be a dynamic marker of the interaction between mechanical ventilation and right heart pressure after cardiac surgery. The PI could be a useful noninvasive tool to monitor venous congestion associated with mechanical ventilation.

Lung ultrasound in outpatients with heart failure: the wet-to-dry HF study

AIMS

In ambulatory patients with chronic heart failure (HF), congestion and decongestion assessment may be challenging. The aim of this study is to assess the value of lung ultrasound (LUS) in outpatients with HF in characterizing decompensation and recompensation, and in outcomes prediction.

METHODS AND RESULTS

Heart failure outpatients attended to establish HF decompensation were included. LUS was blindly performed at baseline (LUS1) and at clinical recompensation (LUS2). B-lines were counted in eight scanned areas. Diagnosis of no HF decompensation vs. right-sided, left-sided, or global HF decompensation, and patients' management were performed by physicians blinded to LUS1. Outcome was the composite of all-cause death or HF-related hospitalization. Two hundred and thirty-three suspicions of HF decompensation were included in 187 patients (71.4 ± 11.3 years, 66.8% men). Mean B-line (LUS1) was 17.6 ± 11.2 vs. 3.7 ± 4.5 for episodes with and without HF decompensation, respectively (P < 0.001). Global HF decompensation showed the highest number of B-lines (20.6 ± 11), followed by left-sided (19.7 ± 11.6) and right-sided (13.5 ± 9.8). B-lines declined to 6.9 ± 6.7 (LUS2) (P < 0.001 vs. LUS1) after treatment, within a mean time of 24.2 ± 23.7 days [median 13.5 days (interquartile range 6-40)]. B-lines were significantly associated with the composite endpoint at 30 days (hazard ratio [HR] 1.04 [95% confidence interval 1.01-1.07], P = 0.02), but not at 60 (P = 0.22) or 180 days (P = 0.54). In multivariable analysis, B-line number remained as an independent predictor of the composite endpoint at 30 days, [HR 1.04 (1.01-1.07), P = 0.014], with a 4% increase risk per B-line added. B-lines correlated significantly with CA125 (R = 0.30, P = 0.001).

CONCLUSIONS

Lung ultrasound supports the diagnostic work-up of congestion and decongestion in chronic HF outpatients and identifies patients at high risk of short-term events.