Right Ventricular Function, Peripheral Edema, and Acute Kidney Injury in Critical Illness

Impact of right ventricular dysfunction on outcomes in patients requiring intra-aortic balloon pump placement: A retrospective nationwide analysis (2016-2020)

Right ventricular dysfunction (RVD) continues to be a significant contributor to both mortality and morbidity, posing a significant challenge in the management of patients undergoing evaluation for mechanical circulatory support (MCS). Currently, there is a paucity of data regarding outcomes in this subset of patients. We analyzed the National Inpatient Sample database (NIS) to identify adult hospitalizations who underwent intra-aortic balloon pump (IABP) placement with or without co-existence of RVD. Multivariate logistic regression, and linear regression analyses were used to compare outcomes, and adjust for possible confounders. Out of 126,985 hospitalizations who underwent IABP placement, 1,475 (1.2%) had RVD. Patients with RVD who received an IABP had higher adjusted odds of inpatient mortality (Adjusted odds ratio [aOR]: 2.33, 95% confidence interval [CI]: 1.7-3.2, p<0.001) than those without co-existing RVD. Hospitalized patients who underwent IABP placement with RVD had higher adjusted odds of worse hospitalization outcomes in general. Conducting additional prospective studies and clinical trials with an emphasis on further subcategorization of patients with RVD is crucial for determining optimal management strategies for these patients.

Clinical Features and Outcomes of Acute Kidney Injury in Critically Ill COVID-19 Patients: A Retrospective Observational Study

BACKGROUND

An alarming number of COVID-19 patients, especially in severe cases, have developed acute kidney injury (AKI).

AIM

The study aimed to assess the frequency, risk factors, and impact of AKI on mortality in critically ill COVID-19 patients.

METHODS

The study was a retrospective observational study conducted in the MICU. Univariate and multivariate analyses were performed to identify risk factors for AKI and clinical outcomes.

RESULTS

During the study period, 465 consecutive COVID-19 patients were admitted to the MICU. The patients' characteristics were median age, 64 [54-71] years; median SAPSII, 31 [24-38]; and invasive mechanical ventilation (IMV), 244 (52.5%). The overall ICU mortality rate was 49%. Two hundred twenty-nine (49.2%) patients developed AKI. The factors independently associated with AKI were positive fluid balance (OR, 2.78; 95%CI [1.88-4.11]; p < 0.001), right heart failure (OR, 2.15; 95%CI [1.25-3.67]; p = 0.005), and IMV use (OR, 1.55; 95%CI [1.01-2.40]; p = 0.044). Among the AKI patients, multivariate analysis identified the following factors as independently associated with ICU mortality: age (OR, 1.05; 95%CI [1.02-1.09]; p = 0.012), IMV use (OR, 48.23; 95%CI [18.05-128.89]; p < 0.001), and septic shock (OR, 3.65; 95%CI [1.32-10.10]; p = 0.012).

CONCLUSION

The present study revealed a high proportion of AKI among critically ill COVID-19 patients. This complication seems to be linked to a severe cardiopulmonary interaction and fluid balance management, thus accounting for a poor outcome.

Cardiovascular Subphenotypes in ARDS: Diagnostic and Therapeutic Implications and Overlap with Other ARDS Subphenotypes

Acute respiratory distress syndrome (ARDS) is a highly heterogeneous clinical condition. Shock is a poor prognostic sign in ARDS, and heterogeneity in its pathophysiology may be a barrier to its effective treatment. Although right ventricular dysfunction is commonly implicated, there is no consensus definition for its diagnosis, and left ventricular function is neglected. There is a need to identify the homogenous subgroups within ARDS, that have a similar pathobiology, which can then be treated with targeted therapies. Haemodynamic clustering analyses in patients with ARDS have identified two subphenotypes of increasingly severe right ventricular injury, and a further subphenotype of hyperdynamic left ventricular function. In this review, we discuss how phenotyping the cardiovascular system in ARDS may align with haemodynamic pathophysiology, can aid in optimally defining right ventricular dysfunction and can identify tailored therapeutic targets for shock in ARDS. Additionally, clustering analyses of inflammatory, clinical and radiographic data describe other subphenotypes in ARDS. We detail the potential overlap between these and the cardiovascular phenotypes.

Focused liquid ultrasonography in dropsy protocol for quantitative assessment of subcutaneous edema

BACKGROUND

Although subcutaneous edema is a common symptom of critically ill patients, it is still underreported due to the lack of a systematic method for evaluating it. The present study aims to describe the occurrence and distribution of subcutaneous edema, as well as the risk factors associated with it, in critically ill patients using the focused liquid ultrasonography in dropsy (FLUID) protocol, and to assess their impact on ICU mortality.

METHODS

The FLUID protocol and the pitting test were performed on general ICU patients in China. Cohen's Kappa coefficient and Bland-Altman plots were used to evaluate the agreement between the two methods at each measurement site and between the whole-body subcutaneous edema scores, respectively, while a repeated measures ANOVA was performed to compare the differences between the two methods in whole-body and body-part measurements. A generalized linear model was used to evaluate the risk factors for subcutaneous edema development and the relationship between subcutaneous edema severity and ICU mortality.

RESULTS

A total of 145 critically ill patients were evaluated using both approaches, of whom 40 (27.6%) experienced subcutaneous edema. Over 1440 measurements, it was found that ultrasound discovered more subcutaneous edema than the pitting test (ultrasound: 522[36.3%], pitting test: 444[30.8%], χ² = 9.477, p = 0.002). The FLUID protocol scored edema severity significantly higher than the pitting test in the whole body and specific body parts, including the abdominal wall, thighs, chest wall, and hands. Subcutaneous edema exhibited gravity-dependent distribution patterns, particularly in the abdominal wall. The APACHE II, NT-proBNP, serum creatinine, and sepsis were independent risk factors for subcutaneous edema development. The score of ultrasonic subcutaneous edema was related to ICU mortality.

CONCLUSIONS

The FLUID protocol provides a comprehensive strategy for the semi-quantitative assessment of subcutaneous edema in critically ill patients. In detecting the onset and severity of edema, ultrasound was found to outperform the pitting test. Subcutaneous edema showed a gravity-dependent distribution pattern, and its severity was associated with mortality.

Invasive management of significant tricuspid regurgitation in clinical practice

BACKGROUND

Tricuspid regurgitation (TR) is a prevalent condition inside valvular heart disease (VHD) with relevant prognosis implications. However, concordance between real management in clinical practice and invasive treatment recommendations of European Society of Cardiology (ESC) guidelines is unknown.

METHODS

A substudy of ESC VHD II survey was performed to evaluate the real treatment of TR compared to the clinical ESC guidelines recommendations published in 2012, 2017 and 2021 was performed. TR cases with surgical indication were divided in 3 groups: 1: severe isolated TR without previous left VHD; 2: moderate/severe TR and concomitant severe left VHD; 3: severe TR plus previous left VHD surgery.

RESULTS

Of 902 patients assessed, 123 had significant TR. Fifty (41%) cases demonstrated ESC guidelines 2012-2017 Class I or IIa recommendations for invasive treatment: 9(18%) of group 1, 37(74%) of group 2 and 4(8%) of group 3. Surgery was performed in 24 patients (48%); 1 in group 1(4%), 22 in group 2(92%) and 1 in group 3(4%). Overall concordance was 48% (group 1: 11%; group 2: 59%; group 3: 25%). Regarding the 2021 ESC guidelines only one patient changed groups with an overall concordance of 47% (group 1: 10%; group 2: 59%; group 3: 25%).

CONCLUSION

Concordance between 2012, 2017 and 2021 ESC guidelines recommendations and clinical practice for TR surgical intervention is low, especially in those without concomitant severe left VHD. These results suggest the need to improve further guideline implementation and alternative treatments, such as percutaneous, which could resolve potential discrepancies in those clinical scenarios.

Acute Cardiorenal Syndrome: Epidemiology, Pathophysiology, Assessment, and Treatment

Acute cardiorenal syndrome (CRS) is often observed in patients with acute kidney injury (AKI) in the cardiac intensive care unit and is reported to be associated with poor prognosis. Volume disorder or re-distribution, renin-angiotensin-aldosterone system activation, and neurohormonal and sympathetic nervous system activation have been suggested to be related to the occurrence of acute CRS. There is a lack of biomarkers that can identify changes in renal function in patients with acute CRS. Evidence-based medications are limited in the management of acute CRS in AKI. Therefore, we reviewed the epidemiology, pathophysiology, clinical assessment, and treatment of acute CRS in AKI.

Pathophysiology of Acute Kidney Injury in Critical Illness: A Narrative Review

Acute kidney injury (AKI) is a syndrome that entails a rapid decline in kidney function with or without injury. The consequences of AKI among acutely ill patients are dire and lead to higher mortality, morbidity, and healthcare cost. To prevent AKI and its short and long-term repercussions, understanding its pathophysiology is essential. Depending on the baseline kidney histology and function reserves, the number of kidney insults, and the intensity of each insult, the clinical presentation of AKI may differ. While many factors are capable of inducing renal injury, they can be categorized into a few processes. The three primary processes reported in the literature are hemodynamic changes, inflammatory reactions, and nephrotoxicity. The majority of patients with AKI will suffer from more than one during their development and/or progression of AKI. Moreover, the development of one usually leads to the instigation of another. Thus, the interactions and progression between these mechanisms may determine the severity and duration of the AKI. Other factors such as organ crosstalk and how our concurrent therapies interact with these mechanisms complicate the pathophysiology of the progression of the AKI even further. In this narrative review article, we describe these three main pathophysiological processes that lead to the development and progression of AKI. © 2022 American Physiological Society. Compr Physiol 12: 1-14, 2022.

Acute Kidney Injury in Critically-Ill COVID-19 Patients

Purpose: Acute kidney injury (AKI) is common in patients with COVID-19, however, its mechanism is still controversial, particularly in ICU settings. Urinary proteinuria profile could be a non-invasive tool of interest to scrutinize the pathophysiological process underlying AKI in COVID-19 patients. Material and Methods: We conducted a retrospective study between March 2020 and April 2020. All patients with laboratory-confirmed COVID-19 and without end-stage kidney disease requiring renal replacement therapy before ICU admission were included. Our objectives were to assess the incidence and risk factors for AKI and to describe its clinical and biological characteristics, particularly its urinary protein profile. Results: Seventy patients were included; 87% needed mechanical ventilation and 61% needed vasopressor during their ICU stay; 64.3% of patients developed AKI and half of them needed dialysis. Total and tubular proteinuria on day 1 were higher in patients with AKI, whereas glomerular proteinuria was similar in both groups. The main risk factor for AKI was shock at admission (OR = 5.47 (1.74−17.2), p < 0.01). Mortality on day 28 was higher in AKI (23/45, 51.1%) than in no-AKI patients (1/25, 4%), p < 0.001. Risk factors for 28-days mortality were AKI with need for renal replacement therapy, non-renal SOFA score and history of congestive heart failure. Conclusions: AKI is common in COVID-19 patients hospitalized in ICU; it seems to be related to tubular lesions rather than glomerular injury and is related to shock at ICU admission.

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.

Evolving Risk of Acute Kidney Injury in COVID-19 Hospitalized Patients: A Single Center Retrospective Study

Background and Objectives: Within a year, COVID-19 has advanced from an outbreak to a pandemic, spreading rapidly and globally with devastating impact. The pathophysiological link between COVID-19 and acute kidney injury (AKI) is currently being debated among scientists. While some studies have concluded that the mechanisms of AKI in COVID-19 patients are complex and not fully understood, others have claimed that AKI is a rare complication of COVID-19-related disorders. Considering this information gap and its possible influence on COVID-19-associated AKI management, our study aimed to explore the prevalence of AKI and to identify possible risk factors associated with AKI development among COVID-19 hospitalized patients. Materials and Methods: A retrospective cohort study included 83 laboratory-confirmed COVID-19 patients hospitalized at the isolation department in a tertiary hospital in Zagazig City, Egypt between June and August 2020. Patients younger than 18 years of age, those diagnosed with end-stage kidney disease, or those on nephrotoxic medications were excluded. All study participants had a complete blood count, liver and renal function tests, hemostasis parameters examined, inflammatory markers, serum electrolytes, routine urinalysis, arterial blood gas, and non-enhanced chest and abdominal computer tomography (CT) scans. Results: Of the 83 patients, AKI developed in 24 (28.9%) of them, of which 70.8% were in stage 1, 8.3% in stage 2, and 20.8% in stage 3. Patients with AKI were older than patients without AKI, with hypertension and diabetes being the most common comorbidities. Risk factors for AKI include increased age, hypertension, diabetes mellitus, and a higher sequential organ failure assessment (SOFA) score. Conclusions: AKI occurs in a considerable percentage of patients with COVID-19, especially in elderly males, those with hypertension, diabetes, and a higher sequential organ failure assessment (SOFA) score. Hence, the presence of AKI should be taken into account as an important index within the risk spectrum of disease severity for COVID-19 patients.

Right Ventricular Function in Acute Respiratory Distress Syndrome: Impact on Outcome, Respiratory Strategy and Use of Veno-Venous Extracorporeal Membrane Oxygenation

Acute respiratory distress syndrome (ARDS) is characterized by protein-rich alveolar edema, reduced lung compliance and severe hypoxemia. Despite some evidence of improvements in mortality over recent decades, ARDS remains a major public health problem with 30% 28-day mortality in recent cohorts. Pulmonary vascular dysfunction is one of the pivot points of the pathophysiology of ARDS, resulting in a certain degree of pulmonary hypertension, higher levels of which are associated with morbidity and mortality. Pulmonary hypertension develops as a result of endothelial dysfunction, pulmonary vascular occlusion, increased vascular tone, extrinsic vessel occlusion, and vascular remodeling. This increase in right ventricular (RV) afterload causes uncoupling between the pulmonary circulation and RV function. Without any contractile reserve, the right ventricle has no adaptive reserve mechanism other than dilatation, which is responsible for left ventricular compression, leading to circulatory failure and worsening of oxygen delivery. This state, also called severe acute cor pulmonale (ACP), is responsible for excess mortality. Strategies designed to protect the pulmonary circulation and the right ventricle in ARDS should be the cornerstones of the care and support of patients with the severest disease, in order to improve prognosis, pending stronger evidence. Acute cor pulmonale is associated with higher driving pressure (≥18 cmH₂O), hypercapnia (PaCO₂ ≥ 48 mmHg), and hypoxemia (PaO₂/FiO₂ < 150 mmHg). RV protection should focus on these three preventable factors identified in the last decade. Prone positioning, the setting of positive end-expiratory pressure, and inhaled nitric oxide (INO) can also unload the right ventricle, restore better coupling between the right ventricle and the pulmonary circulation, and correct circulatory failure. When all these strategies are insufficient, extracorporeal membrane oxygenation (ECMO), which improves decarboxylation and oxygenation and enables ultra-protective ventilation by decreasing driving pressure, should be discussed in seeking better control of RV afterload. This review reports the pathophysiology of pulmonary hypertension in ARDS, describes right heart function, and proposes an RV protective approach, ranging from ventilatory settings and prone positioning to INO and selection of patients potentially eligible for veno-venous extracorporeal membrane oxygenation (VV ECMO).

Evaluation of ventricular systolic dysfunction as a risk factor for acute kidney injury in intensive care unit

Background

Heart failure (HF) is a major health problem. Cardiac and renal diseases interact in a complex bidirectional manner in both acute and chronic settings. Renal dysfunction in the setting of heart failure, termed the cardio renal syndrome (CRS), has been considered consequence of left ventricular dysfunction (LVD), whereby decreasing cardiac output (COP) results in renal under perfusion and consequent decreased glomerular filtration rate (GFR).

Main body of the abstract

This study showed that 500 patients were admitted to internal care unit (ICU), and out of them, 100 (20%) patients developed acute kidney injury (AKI) while 400 (80%) patients did not develop AKI. It is also showed that 67 (67%) of those with AKI and 100 (25%) of those with no-AKI had baseline ventricular systolic dysfunction, left ventricular dysfunction (LVD), right ventricular dysfunction (RVD), and biventricular dysfunction (BiVD)presented in 23 (23%), 16 (16%), and 28 (28%) patients of AKI group, respectively, and presented in 60 (15%), 30 (7.50%), and 10 (2.50%) patients, respectively, in patients without acute kidney injury (AKI)

Short conclusion

Our study revealed that AKI has highest incidence in patient with biventricular dysfunction followed by left ventricular dysfunction and lastly those with right ventricular dysfunction.

Cardiorenal Syndrome: Emerging Role of Medical Imaging for Clinical Diagnosis and Management

Cardiorenal syndrome (CRS) concerns the interconnection between heart and kidneys in which the dysfunction of one organ leads to abnormalities of the other. The main clinical challenges associated with cardiorenal syndrome are the lack of tools for early diagnosis, prognosis, and evaluation of therapeutic effects. Ultrasound, computed tomography, nuclear medicine, and magnetic resonance imaging are increasingly used for clinical management of cardiovascular and renal diseases. In the last decade, rapid development of imaging techniques provides a number of promising biomarkers for functional evaluation and tissue characterization. This review summarizes the applicability as well as the future technological potential of each imaging modality in the assessment of CRS. Furthermore, opportunities for a comprehensive imaging approach for the evaluation of CRS are defined.

A preliminary study of influences of hydroxyethyl starch combined with ulinastatin on degree of edema in newborns with capillary leak syndrome

OBJECTIVE

To analyze the efficacy of hydroxyethyl starch (HES) combined with Ulinastatin (Uti) in the treatment of newborns with capillary leak syndrome (CLS).

METHODS

A total of 60 newborns with CLS admitted to four hospitals were selected as the study subjects, and were randomly divided into the control group (n = 30) and the observation group (n = 30) in accordance with the random number table. The control group was treated with HES alone, while the observation group was treated with Uti combined with HES.

RESULTS

At 5 d after treatment, the incidence rates of systemic edema and pulmonary edema, the levels of CRP, NE, and BUN, and the duration for the improvement of systemic edema, pulmonary edema and NICU hospital stay in the control group were superior to those in the observation group, while the 24-h urine output, PaO₂ and MAP levels, the levels of A, SCr, ALT, and IL-10 in the observation group were superior to those in the control group (P < 0.05). After 3 months of follow-up after treatment, the mortality rate of newborns in the observation group (13.33%) was lower than that in the control group (36.67%) (P < 0.05).

CONCLUSION

HES combined with Uti can effectively alleviate edema, control inflammatory levels, and improve hepatic and renal functions and neonatal survival rate of newborns with CLS.

Cardio-pulmonary-renal interactions in ICU patients. Role of mechanical ventilation, venous congestion and perfusion deficit on worsening of renal function: Insights from the MIMIC-III database

Background Mechanical ventilation (MV) in ICU patients may impact hemodynamics and renal function. We aimed to describe the interactions of MV settings, hemodynamic parameters and worsening of renal function (WRF). Methods We included adult patients admitted for the first time in the ICU from the MIMIC-III database. Mean arterial blood pressure (mABP), central venous pressure (CVP) and positive end-expiratory pressure (PEEP) were collected and summarized as a time-weighted mean. The main outcome was WRF defined as acute kidney injury (AKI) occurrence or one-KDIGO stage worsening compared to the KDIGO stage the day before. We used a multinomial logistic regression at day 1 (ldmk-1) and day 2 (ldmk-2) according to a landmark-approach, with a two-days sliding perspective. Results 27,248/61,051 patients met the inclusion criteria (15,258 male (56.0%); 60.1% over 60 y). ICU and hospital mortality were 7.4 and 10.7%, respectively. MV was independently associated with WRF in the ldmrk-1 and -2 models (relative risk ratio [RRR] 8.15 [6.58;10.11] and 7.08 [3.97;12.61] at day-3 and 4, respectively). In MV patients, PEEP was associated with WRF in the ldmrk-1 and -2 models (RRR 1.36 [1.16, 1.6] and 1.17 [0.88, 1.56] by 1 cmH₂O increase at day-3 and 4, respectively). Mean perfusion pressure decreased while central venous pressure increased over PEEP categories. In multivariable analysis, mABP, CVP and PEEP were independently associated with WRF. Conclusion In this large cohort of ICU patients, we observed a strong relationship between MV and WRF. PEEP was associated with WRF in MV patients. This association relied at least partly on renal venous congestion.

Change in right ventricular systolic function after continuous renal replacement therapy initiation and renal recovery

OBJECTIVE

To describe the associations between right ventricular (RV) function and outcomes of patients with acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT).

METHODS

This is a retrospective study, conducted 2006-2015 at an academic hospital in USA. We included patients with AKI requiring CRRT who had paired echocardiograms within 2 weeks before and after CRRT initiation. We defined improvement in RV systolic function as 2-point improvement on the semiquantitative scale.

RESULTS

The cohort included 201 patients. The mean(±SD) age was 59(±16) years with 83(41%) female. The median time of the pre and post echocardiograms relative to CRRT initiation were - 1 day (IQR-3;0) prior to and 3 days (IQR1;7) after CRRT initiation. Thirty-one (15%) patients showed an improvement in their RV function. Using a multivariable logistic regression model, improvement in RV systolic function was associated with lower odds of major adverse kidney events (composite of mortality, need for dialysis or persistently elevated serum creatinine) at 90 days with odds ratio (OR) of 0.37(95%CI:0.17-0.84, p.016). Positive cumulative fluid balance was associated with lower odds of improvement in RV function (OR 0.95 per 1-l increase, p 0.045).

CONCLUSION

Serial assessment of RV function among patients with AKI requiring CRRT could provide prognostic value.

Contemporary Management of Severe Acute Kidney Injury and Refractory Cardiorenal Syndrome: JACC Council Perspectives

Acute kidney injury (AKI) and cardiorenal syndrome (CRS) are increasingly prevalent in hospitalized patients with cardiovascular disease and remain associated with poor short- and long-term outcomes. There are no specific therapies to reduce mortality related to either AKI or CRS, apart from supportive care and volume status management. Acute renal replacement therapies (RRTs), including ultrafiltration, intermittent hemodialysis, and continuous RRT are used to manage complications of medically refractory AKI and CRS and may restore normal electrolyte, acid-base, and fluid balance before renal recovery. Patients who require acute RRT have a significant risk of mortality and long-term dialysis dependence, emphasizing the importance of appropriate patient selection. Despite the growing use of RRT in the cardiac intensive care unit, there are few resources for the cardiovascular specialist that integrate the epidemiology, diagnostic workup, and medical management of AKI and CRS with an overview of indications, multidisciplinary team management, and transition off of RRT.

New insights into the pathophysiological mechanisms underlying cardiorenal syndrome

Communication between the heart and kidney occurs through various bidirectional pathways. The heart maintains continuous blood flow through the kidney while the kidney regulates blood volume thereby allowing the heart to pump effectively. Cardiorenal syndrome (CRS) is a pathologic condition in which acute or chronic dysfunction of the heart or kidney induces acute or chronic dysfunction of the other organ. CRS type 3 (CRS-3) is defined as acute kidney injury (AKI)-mediated cardiac dysfunction. AKI is common among critically ill patients and correlates with increased mortality and morbidity. Acute cardiac dysfunction has been observed in over 50% of patients with severe AKI and results in poorer clinical outcomes than heart or renal dysfunction alone. In this review, we describe the pathophysiological mechanisms responsible for AKI-induced cardiac dysfunction. Additionally, we discuss current approaches in the management of patients with CRS-3 and the development of targeted therapeutics. Finally, we summarize current challenges in diagnosing mild cardiac dysfunction following AKI and in understanding CRS-3 etiology.

Acute kidney injury in critically ill patients with COVID-19

Acute kidney injury (AKI) has been reported in up to 25% of critically-ill patients with SARS-CoV-2 infection, especially in those with underlying comorbidities. AKI is associated with high mortality rates in this setting, especially when renal replacement therapy is required. Several studies have highlighted changes in urinary sediment, including proteinuria and hematuria, and evidence of urinary SARS-CoV-2 excretion, suggesting the presence of a renal reservoir for the virus. The pathophysiology of COVID-19 associated AKI could be related to unspecific mechanisms but also to COVID-specific mechanisms such as direct cellular injury resulting from viral entry through the receptor (ACE2) which is highly expressed in the kidney, an imbalanced renin-angotensin-aldosteron system, pro-inflammatory cytokines elicited by the viral infection and thrombotic events. Non-specific mechanisms include haemodynamic alterations, right heart failure, high levels of PEEP in patients requiring mechanical ventilation, hypovolemia, administration of nephrotoxic drugs and nosocomial sepsis. To date, there is no specific treatment for COVID-19 induced AKI. A number of investigational agents are being explored for antiviral/immunomodulatory treatment of COVID-19 and their impact on AKI is still unknown. Indications, timing and modalities of renal replacement therapy currently rely on non-specific data focusing on patients with sepsis. Further studies focusing on AKI in COVID-19 patients are urgently warranted in order to predict the risk of AKI, to identify the exact mechanisms of renal injury and to suggest targeted interventions.

Clinical examination findings as predictors of acute kidney injury in critically ill patients

BACKGROUND

Acute Kidney Injury (AKI) in critically ill patients is associated with a markedly increased morbidity and mortality. The aim of this study was to establish the predictive value of clinical examination for AKI in critically ill patients.

METHODS

This was a sub-study of the SICS-I, a prospective observational cohort study of critically ill patients acutely admitted to the Intensive Care Unit (ICU). Clinical examination was performed within 24 hours of ICU admission. The occurrence of AKI was determined at day two and three after admission according to the KDIGO definition including serum creatinine and urine output. Multivariable regression modeling was used to assess the value of clinical examination for predicting AKI, adjusted for age, comorbidities and the use of vasopressors.

RESULTS

A total of 1003 of 1075 SICS-I patients (93%) were included in this sub-study. 414 of 1003 patients (41%) fulfilled the criteria for AKI. Increased heart rate (OR 1.12 per 10 beats per minute increase, 98.5% CI 1.04-1.22), subjectively cold extremities (OR 1.52, 98.5% CI 1.07-2.16) and a prolonged capillary refill time on the sternum (OR 1.89, 98.5% CI 1.01-3.55) were associated with AKI. This multivariable analysis yielded an area under the receiver-operating curve (AUROC) of 0.70 (98.5% CI 0.66-0.74). The model performed better when lactate was included (AUROC of 0.72, 95%CI 0.69-0.75), P = .04.

CONCLUSION

Clinical examination findings were able to predict AKI with moderate accuracy in a large cohort of critically ill patients. Findings of clinical examination on ICU admission may trigger further efforts to help predict developing AKI.

Acute Kidney Injury, Heart Failure, and Health Outcomes

Acute kidney injury in acute decompensated heart failure leads to increased readmissions regardless of being transient or sustained at the time of discharge. Timely identification of acute kidney injury and worsening heart failure in patients with acute decompensated heart failure is of utmost importance to optimize different components of heart failure treatment. Acute kidney injury is a strong predictor of poor outcomes and early death in patients with pulmonary artery hypertension and acute right-sided heart failure. Extracorporeal ultrafiltration should not be used as an initial or alternative to diuretic therapy. It should be reserved for diuretic-resistant individuals.

Exaggerated Interventricular Dependence among Trauma and Burn Patients: A Relationship with Kidney Function—An Exploratory Study

Acute kidney injury (AKI) is a serious condition that affects critically ill patients admitted to the ICU. In this study, we report the association between right ventricle shape and AKI in a cohort of burn and trauma patients. This study is a retrospective review of trauma and burn patients who were admitted to our ICU between 2013 and 2016 who underwent hemodynamic transesophageal echocardiography. Left ventricular eccentricity index (LVEI) measurements were performed on still images obtained from transgastric short-axis view clips at end diastole. LVEI was used as a surrogate of right ventricular volume loading. There were 132 patients, the mean age was 50.8 years, and they were predominantly white and males. Using logistic regression and adjusting for age, race, gender, injury mechanism, and injury severity, higher LVEI was independently significantly associated with lower incidence of AKI (odds ratio 0.03, confidence interval 0.00–0.69). Higher LVEI is associated with a lower incidence of AKI in critically injured trauma and burn patients.

Associations between tricuspid annular plane systolic excursion to reflect right ventricular function and acute kidney injury in critically ill patients: a SICS-I sub-study

BACKGROUND

Acute kidney injury (AKI) occurs in up to 50% of all critically ill patients and hemodynamic abnormalities are assumed to contribute, but their nature and share is still unclear. We explored the associations between hemodynamic variables, including cardiac index and right ventricular function, and the occurrence of AKI in critically ill patients.

METHODS

In this prospective cohort study, we included all patients acutely admitted to an intensive care unit (ICU). Within 24 h after ICU admission clinical and hemodynamic variables were registered including ultrasonographic measurements of cardiac index and right ventricular function, assessed using tricuspid annular plane systolic excursion (TAPSE) and right ventricular systolic excursion (RV S'). Maximum AKI stage was assessed according to the KDIGO criteria during the first 72 h after admission. Multivariable logistic regression modeling was used including both known predictors and univariable significant predictors of AKI. Secondary outcomes were days alive outside ICU and 90-day mortality.

RESULTS

A total of 622 patients were included, of which 338 patients (54%) had at least AKI stage 1 within 72 h after ICU admission. In the final multivariate model higher age (OR 1.01, 95% CI 1.00-1.03, for each year), higher weight (OR 1.03 CI 1.02-1.04, for each kg), higher APACHE IV score (OR 1.02, CI 1.01-1.03, per point), lower mean arterial pressure (OR 1.02, CI 1.01-1.03, for each mmHg decrease) and lower TAPSE (OR 1.05, CI 1.02-1.09 per millimeter decrease) were all independent predictors for AKI in the final multivariate logistic regression model. Sepsis, cardiac index, RV S' and use of vasopressors were not significantly associated with AKI in our data. AKI patients had fewer days alive outside of ICU, and their mortality rate was significantly higher than those without AKI.

CONCLUSIONS

In our cohort of acutely admitted ICU patients, the incidence of AKI was 54%. Hemodynamic variables were significantly different between patients with and without AKI. A worse right ventricle function was associated with AKI in the final model, whereas cardiac index was not.

Possible applications of normative lower to upper limb ratios of tissue dielectric constant to lower extremity edema

BACKGROUND

Lower extremity edema occurs in many conditions including congestive heart failure, lymphedema, diabetes-related, kidney and liver disease, chronic venous insufficiency with venous hypertension. Clinical edema assessment methods are often subjective and variable. Our goals were to introduce a simple noninvasive measurement procedure potentially useful to characterize lower extremity edema by providing normative values from which edema thresholds might emerge.

METHODS

Tissue dielectric constant (TDC) values, as indices of skin-to-fat tissue water, were measured on foot dorsum, lower medial leg and anterior forearm of 88 adults (44 female) with ages ranging from 19-77 years with BMI ranging from 18.3-40.6 kg/m2. From these direct measurements lower-to-upper extremity TDC ratios (foot/arm and leg/arm) were determined for each gender. Possible edema threshold ratios were calculated as the mean lower-to-upper ratio to which was added two standard deviations of the overall ratio thereby providing initial thresholds for future testing.

RESULTS

Results showed that at each anatomical site absolute TDC values for males significantly exceed those of females (P<0.001). Male vs. female TDC values were 33.0±5.4 vs. 27.7±4.0 for the forearm, 34.8±6.5 vs. 27.5±4.6 for the leg, and 32.5±6.5 vs. 28.7±5.1 for the foot. In contrast, the foot/arm and leg/arm ratios were similar between genders ranging 0.990±0.144 to 1.063±0.170. Corresponding lower extremity to upper extremity threshold ratios ranged from 1.278 for foot/arm to 1.403 for leg/arm. The composite ratios considering both gender ration (N.=88) yielded a composite threshold foot/arm ratio of 1.387 and a leg/arm threshold ratio of 1.324.

CONCLUSIONS

This assessment method together with the normative ratios and calculated thresholds may aid in rapid detection of lower extremity edema in patients and possibly as a way to quantitatively track changes in edema status with time or treatment. However, the suitability of these thresholds is subject to future validation in persons with clearly defined lower extremity edema for which this report's findings serve as an initial quantitative starting point.

Post-extrasystolic characteristics in the arterial blood pressure waveform are associated with right ventricular dysfunction in intensive care patients

Right ventricular dysfunction (RVD) is associated with end-organ dysfunction and mortality, but has been an overlooked condition in the ICU. We hypothesized that analysis of the arterial waveform in the presence of ventricular extrasystoles could differentiate patients with RVD from patients with a normally functioning right ventricle, because the 2nd and 3rd post-ectopic beat could reflect right ventricular state (pulmonary transit time) during the preceding ectopy. We retrospectively identified patients with echocardiographic evidence of moderate-to-severe RVD and patients with a normal functioning right ventricle (control) from the MIMIC database. We identified waveform records where ECG and arterial pressure were available in combination, simultaneously with echocardiographic evaluation. Ventricular extrasystoles were visually confirmed and the median systolic blood pressure (SBP) of the 2nd and 3rd post-ectopic beats compared with the median SBP of the ten sinus beats preceding the extrasystole. We identified 34 patients in the control group and 24 patients in the RVD group with ventricular extrasystoles. The mean SBP reduction at the 2nd and 3rd beat was lower in the RVD group compared with the control group [- 1.7 (SD: 1.9) % vs. - 3.6 (SD: 1.9) %, p < 0.001], and this characteristic differentiated RVD subjects from control subjects with an AUC of 0.76 (CI [0.64; 0.89]), with a specificity of 91% and sensitivity of 50%. In this proof-of-concept study, we found that post-extrasystolic ABP characteristics were associated with RVD.