Fluid overload is an independent risk factor for acute kidney injury in critically Ill patients: results of a cohort study

Fluid administration and fluid accumulation in intensive care units-Protocol for an international inception cohort study (FLUID-ICU)

INTRODUCTION

Fluid accumulation is associated with adverse outcomes in critically ill patients admitted to the intensive care unit (ICU). Fluid administration in the ICU may be a clinically relevant source of fluid accumulation in ICU patients. However, the extent is unknown, and no standard definition exists. We aim to provide epidemiological data on fluid accumulation, risk factors, use of fluid removal strategies, patient outcomes and describe current fluid administration practices in the ICU.

METHODS

We will conduct an international 14-day inception cohort study including a minimum of 1000 acutely admitted adult ICU patients. Data will be collected from medical records and laboratory reports at baseline and daily from ICU admission to discharge with a maximum of 28 days. Follow-up will be performed on day 90 after inclusion. The primary outcome is the number of patients with fluid accumulation. Secondary outcomes include the number of days with fluid accumulation, use of active fluid removal, days alive without life support at day 28, days alive and out of hospital day 90, and all-cause mortality at day 90. Furthermore, we will assess risk factors for fluid accumulation and its association with 90-day mortality and report on the types of fluid administration.

CONCLUSION

This international inception cohort study will provide contemporary epidemiological data on fluid administration and fluid accumulation in adult ICU patients.

The Impact of Fluid Balance on Acute Kidney Injury in Nontraumatic Subarachnoid Hemorrhage

Background: Nontraumatic subarachnoid hemorrhage (SAH) can lead to poor neurologic outcomes, particularly when delayed cerebral ischemia (DCI) occurs. Maintenance of euvolemia following SAH is thought to reduce the risk of DCI. However, attempts at maintaining euvolemia often err on the side of hypervolemia. In this study, we assessed the relationship between fluid balance and acute kidney injury (AKI) in SAH patients, assessing hypervolemia versus euvolemia and their impact on AKI. Methods: In a quaternary care center, neuroscience intensive care unit we conducted a retrospective longitudinal analysis in adult patients who suffered a nontraumatic SAH. Results: Out of 139 patients, 15 (10.8%) patients developed an AKI while hospitalized, with 7 stage I, 3 stage II, and 5 stage III injuries. Acute kidney injury patients had higher peak sodium (150.1 mEq/L vs 142.7 mEq/L, 95% confidence interval [CI]: [2.7-12.1 mEq/L]), higher discharge chloride (109.1 mEq/L vs 104.9 mEq/L, 95% CI: [0.7-7.6 mEq/L]), and lower hemoglobin at discharge (9.3 g/dL vs 11.3 g/dL, 95% CI: [1.0-2.9 g/dL]). At 7 days, AKI patients had a fluid balance that was 1.82 L higher (P = .04), and 3.38 L higher at 14 days (P = .02), in comparison to day 3. Acute kidney injury was associated with significant mortality increases. This increase in mortality was found at 30 days from admission with a 9.52-fold increase, and at 60 days with a 6.25-fold increase. As a secondary outcome, vasospasm (19 patients, 13.7%) showed no association with AKI. Conclusions: Acute kidney injury following SAH is correlated with clinically significant hypervolemia, elevated sodium, elevated chloride, decreased urine output, and decreased hemoglobin at discharge-risk factors for all SAH patients. This study further elucidates the harm of hypervolemia and gives greater practical evidence to physicians attempting to balance the dangers of vasospasm and AKI.

Early Fluid Is Less Fluid: Comparing Early Versus Late ICU Resuscitation in Severely Injured Trauma Patients

OBJECTIVES

The temporal trends of crystalloid resuscitation in severely injured trauma patients after ICU admission are not well characterized. We hypothesized early crystalloid resuscitation was associated with less volume and better outcomes than delaying crystalloid.

DESIGN

Retrospective, observational.

SETTING

High-volume level 1 academic trauma center.

PATIENTS

Adult trauma patients admitted to the ICU with emergency department serum lactate greater than or equal to 4 mmol/dL, elevated lactate (≥ 2 mmol/L) at ICU admission, and normal lactate by 48 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For the 333 subjects, we analyzed patient and injury characteristics and the first 48 hours of ICU course. Receipt of greater than or equal to 500 mL/hr of crystalloid in the first 6 hours of ICU admission was used to distinguish early vs. late resuscitation. Outcomes included ICU length of stay (LOS), ventilator days, and acute kidney injury (AKI). Unadjusted and multivariable regression methods were used to compare early resuscitation vs. late resuscitation. Compared with the early resuscitation group, the late resuscitation group received more volume by 48 hours (5.5 vs. 4.1 L; p ≤ 0.001), had longer ICU LOS (9 vs. 5 d; p ≤ 0.001), more ventilator days (5 vs. 2 d; p ≤ 0.001), and higher occurrence rate of AKI (38% vs. 11%; p ≤ 0.001). On multivariable regression, late resuscitation remained associated with longer ICU LOS and ventilator days and higher odds of AKI.

CONCLUSIONS

Delaying resuscitation is associated with both higher volumes of crystalloid by 48 hours and worse outcomes compared with early resuscitation. Judicious crystalloid given early in ICU admission could improve outcomes in the severely injured.

Venous Congestion Assessed by Venous Excess Ultrasound (VExUS) and Acute Kidney Injury in Children with Right Ventricular Dysfunction

Background

Right ventricular dysfunction (RVD) is a complication following congenital cardiac surgery in children and can lead to systemic venous congestion, low cardiac output, and organ dysfunction. Venous congestion can be transmitted backwards and adversely affect encapsulated organs such as the kidneys.

Primary objective

To investigate the association between systemic venous congestion, as estimated by Venous Excess Ultrasound (VExUS), and the occurrence of acute kidney injury (AKI) in children with RVD following congenital heart surgery. Secondary objectives included comparing changes in VExUS scores after initiating treatment for RVD and venous congestion.

Methods and results

This was a prospective observational study in children with RVD. The VExUS study was performed on day 1, day 2, and day 3 and categorized as VExUS-1, VExUS-2, and VExUS-3. Among 43 patients with RVD and dilated inferior vena cava, 19/43 (44%), 10/43 (23%), and 12/43 (28%) were VExUS-2 and VExUS-3, respectively. There was an association between severe RVD and elevated pulmonary artery systolic pressures and a VExUS score >2. A significant association was observed between central venous pressure (CVP) measurements and VExUS. Among 31 patients with a high VExUS score >2, 18 (58%) had AKI. Additionally, improvement in CVP and fluid balance was associated with improving VExUS scores following targeted treatment for RVD.

Conclusion

VExUS serves as a valuable bedside tool for diagnosing and grading venous congestion through ultrasound Doppler. An elevated VExUS score was associated with the occurrence of AKI, and among the components of VExUS, portal vein pulsatility may be useful as a predictor of AKI.

How to cite this article

Natraj R, Bhaskaran AK, Rola P, Haycock K, Siuba MTT, Ranjit S. Venous Congestion Assessed by Venous Excess Ultrasound (VExUS) and Acute Kidney Injury in Children with Right Ventricular Dysfunction. Indian J Crit Care Med 2024;28(5):447-452.

Development of a new miniaturized system for ultrafiltration

Acute decompensated heart failure and fluid overload are the most common causes of hospitalization in heart failure patients, and often, they contribute to disease progression. Initial treatment encompasses intravenous diuretics although there might be a percentual of patients refractory to this pharmacological approach. New technologies have been developed to perform extracorporeal ultrafiltration in fluid overloaded patients. Current equipment allows to perform ultrafiltration in most hospital and acute care settings. Extracorporeal ultrafiltration is then prescribed and conducted by specialized teams, and fluid removal is planned to restore a status of hydration close to normal. Recent clinical trials and European and North American practice guidelines suggest that ultrafiltration is indicated for patients with refractory congestion not responding to medical therapy. Close interaction between nephrologists and cardiologists may be the key to a collaborative therapeutic effort in heart failure patients. Further studies are today suggesting that wearable technologies might become available soon to treat patients in ambulatory and de-hospitalized settings. These new technologies may help to cope with the increasing demand for the care of chronic heart failure patients. Herein, we provide a state-of-the-art review on extracorporeal ultrafiltration and describe the steps in the development of a new miniaturized system for ultrafiltration, called AD1 (Artificial Diuresis).

Influence of fluid accumulation on major adverse kidney events in critically ill patients - an observational cohort study

BACKGROUND

Fluid accumulation (FA) is known to be associated with acute kidney injury (AKI) during intensive care unit (ICU) stay but data on mid-term renal outcome is scarce. The aim of this study was to investigate the association between FA at ICU day 3 and major adverse kidney events in the first 30 days after ICU admission (MAKE30).

METHODS

Retrospective, single-center cohort study including adult ICU patients with sufficient data to compute FA and MAKE30. We defined FA as a positive cumulative fluid balance greater than 5% of bodyweight. The association between FA and MAKE30, including its sub-components, as well as the serum creatinine trajectories during ICU stay were examined. In addition, we performed a sensitivity analysis for the stage of AKI and the presence of chronic kidney disease (CKD).

RESULTS

Out of 13,326 included patients, 1,100 (8.3%) met the FA definition. FA at ICU day 3 was significantly associated with MAKE30 (adjusted odds ratio [aOR] 1.96; 95% confidence interval [CI] 1.67-2.30; p < 0.001) and all sub-components: need for renal replacement therapy (aOR 3.83; 95%CI 3.02-4.84), persistent renal dysfunction (aOR 1.72; 95%CI 1.40-2.12), and 30-day mortality (aOR 1.70; 95%CI 1.38-2.09), p all < 0.001. The sensitivity analysis showed an association of FA with MAKE30 independent from a pre-existing CKD, but exclusively in patients with AKI stage 3. Furthermore, FA was independently associated with the creatinine trajectory over the whole observation period.

CONCLUSIONS

Fluid accumulation is significantly associated with MAKE30 in critically ill patients. This association is independent from pre-existing CKD and strongest in patients with AKI stage 3.

Exploration of factors affecting hemodynamic stability following pheochromocytoma resection - cohort study

Purpose

Surgery is the only way to cure pheochromocytoma; however, postoperative hemodynamic instability is one of the main causes of serious complications and even death. This study's findings provide some guidance for improved clinical management.

Patients and methods

This study was to investigate the factors leading to postoperative hemodynamic instability in the postoperative pathology indicated pheochromocytoma from May 2016 to May 2022. They were divided into two groups according to whether vasoactive drugs were used for a median number of days or more postoperatively. The factors affecting the postoperative hemodynamics in the perioperative period (preoperative, intraoperative, and postoperative) were then evaluated.

Results

The median number of days requiring vasoactive drug support postoperatively was three in 234 patients, while 118 (50.4%) patients required vasoactive drug support for three days or more postoperatively. The results of the multivariate analysis indicated more preoperative colloid use (odds ratio [OR]=1.834, confidence interval [CI]:1.265-2.659, P=0.001), intraoperative use of vasoactive drug (OR=4.174, CI:1.882-9.258, P<0.001), and more postoperative crystalloid solution input per unit of body weight per day (ml/kg/d) (OR=1.087, CI:1.062-1.112, P<0.001) were risk factors for predicting postoperative hemodynamic instability. The optimal cutoff point of postoperative crystalloid use were 42.37 ml/kg/d.

Conclusion

Hemodynamic instability is a key issue for consideration in the perioperative period of pheochromocytoma. The amount of preoperative colloid use, the need for intraoperative vasoactive drugs, and postoperative crystalloid solution are risk factors for predicting postoperative hemodynamic instability (registration number: ChiCT2300071166).

Fluid balance, biomarkers of renal function and mortality in critically ill patients with AKI diagnosed before, or within 24 h of intensive care unit admission: a prospective study

BACKGROUND

To evaluate fluid balance, biomarkers of renal function and its relation to mortality in patients with acute kidney injury (AKI) diagnosed before, or within 24 h of intensive care unit admission.

METHODS

A prospective cohort study considered 773 critically ill patients observed over six years. Pre-intensive care unit-onset AKI was defined as AKI diagnosed before, or within 24 h of intensive care unit admission. Body weight-adjusted fluid balance and fluid balance-adjusted biomarkers of renal function were measured daily for the first three days of intensive care unit admission. Primary outcome was mortality in the intensive care unit.

RESULTS

Prevalence of pre-intensive care unit-onset AKI was 55.1%, of which 55.6% of cases were hospital-acquired and 44.4% were community-acquired. Fluid balance was higher in AKI patients than in non-AKI patients (p < 0.001) and had a negative correlation with urine output (p < 0.01). Positive fluid balance and biomarkers of renal function were independently related to mortality. Multivariate analysis identified the following AKI-related variables associated with increased mortality: (1) In AKI patients: type 1 cardiorenal syndrome (OR 2.00), intra-abdominal hypertension (OR 1.71), AKI stage 3 (OR 2.15) and increase in AKI stage (OR 4.99); 2) In patients with community-acquired AKI: type 1 cardiorenal syndrome (OR 5.16), AKI stage 2 (OR 2.72), AKI stage 3 (OR 4.95) and renal replacement therapy (OR 3.05); and 3) In patients with hospital-acquired AKI: intra-abdominal hypertension (OR 2.31) and increase in AKI stage (OR 4.51).

CONCLUSIONS

In patients with pre-intensive care unit-onset AKI, positive fluid balance is associated with worse renal outcomes. Positive fluid balance and decline in biomarkers of renal function are related to increased mortality, thus in this subpopulation of critically ill patients, positive fluid balance is not recommended and renal function must be closely monitored.

Prolonged intensive care: muscular functional, and nutritional insights from the COVID-19 pandemic

During the coronavirus disease 2019 (COVID-19) pandemic, clinical staff learned how to manage patients enduring extended stays in an intensive care unit (ICU). COVID-19 patients requiring critical care in an ICU face a high risk of experiencing prolonged intensive care (PIC). The use of invasive mechanical ventilation in individuals with severe acute respiratory distress syndrome can cause numerous complications that influence both short-term and long-term morbidity and mortality. Those risks underscore the importance of proactively addressing functional complications. Mitigating secondary complications unrelated to the primary pathology of admission is imperative in minimizing the risk of PIC. Therefore, incorporating strategies to do that into daily ICU practice for both COVID-19 patients and those critically ill from other conditions is significantly important.

An Echocardiographic Approach for the Management of Shock: The Subcostal to Apical, Respiratory to Parasternal-Cardiac to Respiratory, Aortic to Stomach Protocol

Point of care ultrasound has become an integral part of critical care medicine, particularly for recognizing shock etiologies and guiding management. Most of the current ultrasonography guided shock protocols have been tailored towards a qualitative assessment of patients on presentation with shock. Unfortunately, the evolving nature of shock, particularly in the face of resuscitation and physiologic changes, demands a more sophisticated approach. This manuscript serves to present a comprehensive algorithm called the transthoracic Subcostal To Apical, Respiratory to paraSternal and transesophageal Cardiac to Respiratory, Aortic to StomacH ultrasonographic evaluations for the assessment of shock. This protocol is better suited for the critically ill patient in its ability to move beyond pattern recognition and focus on monitoring shock states from their presentation through their evolution. Not only is importance placed on the sequence of the exam, but also the identification of signs of chronic disease, the early incorporation of pulmonary evaluation, and the role for transesophageal imaging in critically ill patients with difficult surface imaging. Given the broad capabilities of bedside ultrasound, the Subcostal To Apical, Respiratory to paraSternal-Cardiac to Respiratory, Aortic to StomacH protocol serves as a multifaceted algorithm allowing for a nuanced and dynamic approach for the resuscitation of critically ill patients in shock.

Congestion in Heart Failure: From the Secret of a Mummy to Today's Novel Diagnostic and Therapeutic Approaches: A Comprehensive Review

This review paper presents a review of the evolution of this disease throughout the centuries, describes and summarizes the pathophysiologic mechanisms, briefly discusses the mechanism of action of diuretics, presents their role in decongesting heart failure in patients, and reveals the data behind ultrafiltration in the management of acutely or chronically decompensated heart failure (ADHF), focusing on all the available data and advancements in this field. Acutely decompensated heart failure (ADHF) presents a critical clinical condition characterized by worsening symptoms and signs of heart failure, necessitating prompt intervention to alleviate congestion and improve cardiac function. Diuretics have traditionally been the mainstay for managing fluid overload in ADHF. Mounting evidence suggests that due to numerous causes, such as coexisting renal failure or chronic use of loop diuretics, an increasing rate of diuretic resistance is noticed and needs to be addressed. There has been a series of trials that combined diuretics of different categories without the expected results. Emerging evidence suggests that ultrafiltration may offer an alternative or adjunctive approach.

Early Fluid is Less Fluid: Comparing Early Versus Late Resuscitation in Severely Injured Trauma Patients

Background

We aimed to characterize the temporal trends of crystalloid resuscitation in severely injured trauma patients after intensive care unit (ICU) admission. Using 500 mL/hr of crystalloid in the first 6 hours of ICU admission to distinguish early versus late resuscitation, we hypothesized early resuscitation was associated with less volume by 48 hours and better outcomes compared with late resuscitation.

Methods

We performed a retrospective review of the trauma registry of a high-volume level 1 academic trauma center to examine adult trauma patients admitted to the ICU (2016-2019) with: with initial serum lactate ≥ 4 mmol/dL, elevated lactate (≥ 2 mmol/L) at ICU admission, and lactate normalization within 48 hours. We analyzed patient and injury characteristics, and the first 48 hours of ICU course. The primary outcome was ICU length of stay (LOS); secondary outcomes included ventilator days, acute kidney injury (AKI), and in-hospital death. We compared subjects who received early resuscitation to those received late resuscitation using unadjusted methods and multivariable regression models.

Results

We analyzed 333 subjects. The late resuscitation group received less volume over the first 24 hours, but surpassed the early group by 48 hours (5.5 vs 4.1L, p ≤ 0.001). The late group had longer ICU LOS (9 vs 5 days, p ≤ 0.001) and ventilator days (5 vs 2 days, p ≤ 0.001), and higher incidence of AKI (38% vs 11%, p ≤ 0.001). On multivariable regression, late resuscitation remained associated with longer ICU LOS and ventilator days, and higher odds of AKI after adjusting for important confounders.

Conclusions

After hemostasis, crystalloid can play an important role in restoration of organ perfusion. Delaying resuscitation is associated with both receipt of higher volumes of crystalloid by 48 hours and worse outcomes compared to early resuscitation. Judicious crystalloid given early in ICU admission could improve outcomes in the severely injured.

Bioimpedance and Duration of Organ Dysfunction in Septic Shock-A Prospective Observational Study

Rationale: Bioimpedance may be a useful tool to guide fluid treatment and avoid organ dysfunction related to fluid overload. Objective: We examined the correlation between bioimpedance and organ dysfunction in patients with septic shock. Methods: Prospective observational study of adult intensive care unit patients fulfilling the sepsis-3 criteria. Bioimpedance was measured using a body composition monitor (BCM) and BioScan Touch i8 (MBS). We measured impedance at inclusion and after 24 h and reported the impedance, change in impedance, bioimpedance-derived fluid balance, and changes in bioimpedance-derived fluid balance. Organ markers on respiratory, circulatory, and kidney function and overall disease severity were ascertained on days 1-7. The effect of bioimpedance on the change in organ function was assessed by mixed effects linear models. We considered P < .01 as significant. Measurements and Main Results: Forty-nine patients were included. None of the single baseline measurements or derived fluid balances were associated with the course of organ dysfunction. Changes in impedance were associated with the course of overall disease severity (P < .001; with MBS), and with changes in noradrenaline dose (P < .001; with MBS) and fluid balance (P < .001; with BCM). The changes in bioimpedance-derived fluid balance were associated with changes in noradrenaline dose (P < .001; with BCM), cumulative fluid balances (P < .001; with MBS), and lactate concentrations (P < .001; with BCM). Conclusions: Changes in bioimpedance were correlated with the duration of overall organ failure, circulatory failure, and fluid status. Single measurements of bioimpedance were not associated with any changes in organ dysfunction.

Fluid management strategies and their interaction with mechanical ventilation: from experimental studies to clinical practice

Patients on mechanical ventilation may receive intravenous fluids via restrictive or liberal fluid management. A clear and objective differentiation between restrictive and liberal fluid management strategies is lacking in the literature. The liberal approach has been described as involving fluid rates ranging from 1.2 to 12 times higher than the restrictive approach. A restrictive fluid management may lead to hypoperfusion and distal organ damage, and a liberal fluid strategy may result in endothelial shear stress and glycocalyx damage, cardiovascular complications, lung edema, and distal organ dysfunction. The association between fluid and mechanical ventilation strategies and how they interact toward ventilator-induced lung injury (VILI) could potentiate the damage. For instance, the combination of a liberal fluids and pressure-support ventilation, but not pressure control ventilation, may lead to further lung damage in experimental models of acute lung injury. Moreover, under liberal fluid management, the application of high positive end-expiratory pressure (PEEP) or an abrupt decrease in PEEP yielded higher endothelial cell damage in the lungs. Nevertheless, the translational aspects of these findings are scarce. The aim of this narrative review is to provide better understanding of the interaction between different fluid and ventilation strategies and how these interactions may affect lung and distal organs. The weaning phase of mechanical ventilation and the deresuscitation phase are not explored in this review.

Hemodynamic and Rhythmologic Effects of Push-Dose Landiolol in Critical Care-A Retrospective Cross-Sectional Study

BACKGROUND

The highly β1-selective beta-blocker Landiolol is known to facilitate efficient and safe rate control in non-compensatory tachycardia or dysrhythmia when administered continuously. However, efficacy and safety data of the also-available bolus formulation in critically ill patients are scarce.

METHODS

We conducted a retrospective cross-sectional study on a real-life cohort of critical care patients, who had been treated with push-dose Landiolol due to sudden-onset non-compensatory supraventricular tachycardia. Continuous hemodynamic data had been acquired via invasive blood pressure monitoring.

RESULTS

Thirty patients and 49 bolus applications were analyzed. Successful heart rate control was accomplished in 20 (41%) cases, rhythm control was achieved in 13 (27%) episodes, and 16 (33%) applications showed no effect. Overall, the heart rate was significantly lower (145 (130-150) vs. 105 (100-125) bpm, p < 0.001) in a 90 min post-application observational period in all subgroups. The median changes in blood pressure after the bolus application did not reach clinical significance. Compared with the ventilation settings before the bolus application, the respiratory settings including the required FiO2 after the bolus application did not differ significantly. No serious adverse events were seen.

CONCLUSIONS

Push-dose Landiolol was safe and effective in critically ill ICU patients. No clinically relevant impact on blood pressure was noted.

Echocardiographic indicators of fluid responsiveness in hospitalized dogs with compromised hemodynamics and tissue hypoperfusion

OBJECTIVE

To evaluate the accuracy of selected echocardiographic variables used to predict fluid responsiveness in hospitalized dogs with compromised hemodynamics and tissue hypoperfusion.

DESIGN

Diagnostic test study in a prospective cohort of hospitalized dogs.

SETTING

Veterinary referral clinics.

ANIMALS

Forty-four hospitalized dogs with compromised hemodynamics and tissue hypoperfusion were utilized in this study.

INTERVENTIONS

Echocardiographic examination before and after fluid replacement with 30 ml/kg of lactated Ringer's solution.

MEASUREMENTS AND MAIN RESULTS

Pre-fluid replacement measurements of velocity of transmitral E wave (E-peak), the left ventricular end-diastolic internal diameter normalized to body weight (LVIDdN), and the left ventricular end-systolic internal diameter normalized to body weight (LVIDsN) were significantly lower in fluid-responsive patients compared with nonresponders (P < 0.001). The area under the receiver operating characteristic curve (AUROC) with its 95% confidence interval (CI) for each significant predictor was as follows: E-peak 0.907 (0.776-1.000, P < 0.001) and LVIDdN 0.919 (0.801-1.000, P < 0.001). The predictive capacity of LVIDsN was not significantly better than chance (AUROC, 0.753; 95% CI, 0.472-1.000, P = 0.078). A significant negative linear correlation was observed between the percentage of increase in velocity-time integral after expansion and the echocardiographic variables LVIDdN (r_s  = -0.452, P = 0.023) and E-peak (r_s  = -0.396, P = 0.008) pre-fluid replacement. The intraobserver and interobserver variability was very low (<5 %) for all measurements.

CONCLUSIONS

In this study using critically ill dogs with compromised hemodynamics and tissue hypoperfusion, pre-fluid replacement measurements of LVIDdN and E-peak adequately predict fluid responsiveness. Because a small number of fluid nonresponders were involved in the present study (11.4%), further studies that include larger numbers of fluid-nonresponsive animals are required.

Prevalence of polymyxin-induced nephrotoxicity and its predictors in critically ill adult patients: A meta-analysis

BACKGROUND

Polymyxin-induced nephrotoxicity is a major safety concern in clinical practice due to long-term adverse outcomes and high mortality.

AIM

To conducted a systematic review and meta-analysis of the prevalence and potential predictors of polymyxin-induced nephrotoxicity in adult intensive care unit (ICU) patients.

METHODS

PubMed, EMBASE, the Cochrane Library and Reference Citation Analysis database were searched for relevant studies from inception through May 30, 2022. The pooled prevalence of polymyxin-induced nephrotoxicity and pooled risk ratios of associated factors were analysed using a random-effects or fixed-effects model by Stata SE ver. 12.1. Additionally, subgroup analyses and meta-regression were conducted to assess heterogeneity.

RESULTS

A total of 89 studies involving 12234 critically ill adult patients were included in the meta-analysis. The overall pooled incidence of polymyxin-induced nephrotoxicity was 34.8%. The pooled prevalence of colistin-induced nephrotoxicity was not higher than that of polymyxin B (PMB)-induced nephrotoxicity. The subgroup analyses showed that nephrotoxicity was significantly associated with dosing interval, nephrotoxicity criteria, age, publication year, study quality and sample size, which were confirmed in the univariable meta-regression analysis. Nephrotoxicity was significantly increased when the total daily dose was divided into 2 doses but not 3 or 4 doses. Furthermore, older age, the presence of sepsis or septic shock, hypoalbuminemia, and concomitant vancomycin or vasopressor use were independent risk factors for polymyxin-induced nephrotoxicity, while an elevated baseline glomerular filtration rate was a protective factor against colistin-induced nephrotoxicity.

CONCLUSION

Our findings indicated that the incidence of polymyxin-induced nephrotoxicity among ICU patients was high. It emphasizes the importance of additional efforts to manage ICU patients receiving polymyxins to decrease the risk of adverse outcomes.

Fluid Overload and Precision Net Ultrafiltration in Critically Ill Patients

BACKGROUND

Fluid overload is present in two-thirds of critically ill patients with acute kidney injury and is associated with morbidity, mortality, and increased healthcare resource utilization. Kidney replacement therapy (KRT) is frequently used for net fluid removal (i.e., net ultrafiltration [UFNET]) in patients with severe oliguric acute kidney injury. However, ultrafiltration has considerable risks associated with it, and there is a need for newer technology to perform ultrafiltration safely and to improve outcomes.

SUMMARY

Caring for a critically ill patient with oliguric acute kidney injury and fluid overload is one of the most challenging problems. Although diuretics are the first-line treatment for management of fluid overload, diuretic resistance is common. Various clinical practice guidelines support fluid removal using ultrafiltration during KRT. Emerging evidence from observational studies in critically ill patients suggests that both slow and fast rates of net fluid removal during continuous kidney replacement therapy are associated with increased mortality compared with moderate UFNET rates. In addition, fast UFNET rates are associated with an increased risk of cardiac arrhythmias. Randomized trials are required to examine whether moderate UFNET rates are associated with a reduced risk of hemodynamic instability, organ injury, and improved outcomes in critically ill patients. There is a need for newer technology for fluid removal in patients who do not meet traditional criteria for initiation of KRT. Emerging newer and miniaturized ultrafiltration devices may address an unmet clinical need.

KEY MESSAGES

Among critically ill patients with acute kidney injury and fluid overload requiring continuous kidney replacement therapy, use of higher and slower UFNET rates compared with moderate UFNET rates might be associated with poor outcomes. Newer minimally invasive technologies may allow for safe and efficient UFNET in patients with acute kidney injury who do not meet criteria for initiation of KRT.

Incremental value of preoperative right ventricular function in predicting moderate to severe acute kidney injury after heart transplantation

Background

Acute kidney injury (AKI) commonly occurs after heart transplantation (HTx), but its association with preoperative right ventricular (RV) function remains unknown. Consequently, we aimed to determine the predictive value of preoperative RV function for moderate to severe AKI after HTx.

Materials and methods

From 1 January 2016 to 31 December 2019, all the consecutive HTx recipients in our center were enrolled and analyzed for the occurrence of postoperative AKI staged by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Conventional RV function parameters, including RV fractional area change (RVFAC) and tricuspid annular plane systolic excursion (TAPSE), were obtained. The primary endpoint was moderate to severe AKI (the KDIGO stage 2 or 3). The secondary endpoints included the impact of AKI on intensive care unit (ICU) mortality, in-hospital mortality, and 1-year mortality.

Results

A total of 273 HTx recipients were included in the study. Postoperative AKI occurred in 209 (77%) patients, including 122 (45%) patients in stage 1 AKI, 49 (18%) patients in stage 2 AKI, and 38 (14%) patients in stage 3 AKI. Patients with higher AKI stage had lower baseline estimated glomerular filtration rate (eGFR), more frequent diabetes, higher right atrial pressure (RAP), longer cardiopulmonary bypass (CPB) duration, more perioperative red blood cell (RBC) transfusions, and worse preoperative RV function. A multivariate logistic regression model incorporating previous diabetes mellitus [odds ratio (OR): 2.21; 95% CI: 1.06–4.61; P = 0.035], baseline eGFR (OR: 0.99; 95% CI: 0.97–0.10; P = 0.037), RAP (OR: 1.05; 95% CI: 1.00–1.10; P = 0.041), perioperative RBC (OR: 1.18; 95% CI: 1.08–1.28; P < 0.001), and TAPSE (OR: 0.84; 95% CI: 0.79–0.91; P < 0.001) was established to diagnose moderate to severe AKI more accurately [the area under the curve (AUC) = 79.8%; Akaike information criterion: 274].

Conclusion

Preoperative RV function parameters provide additional predicting value over clinical and hemodynamic parameters, which are imperative for risk stratification in patients with HTx at higher risk of AKI.

Loop diuretics in adult intensive care patients with fluid overload: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Fluid overload is a risk factor for organ dysfunction and death in intensive care unit (ICU) patients, but no guidelines exist for its management. We systematically reviewed benefits and harms of a single loop diuretic, the predominant treatment used for fluid overload in these patients.

METHODS

We conducted a systematic review with meta-analysis and Trial Sequential Analysis (TSA) of a single loop diuretic vs. other interventions reported in randomised clinical trials, adhering to our published protocol, the Cochrane Handbook, and PRISMA statement. We assessed the risks of bias with the ROB2-tool and certainty of evidence with GRADE. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020184799).

RESULTS

We included 10 trials (804 participants), all at overall high risk of bias. For loop diuretics vs. placebo/no intervention, we found no difference in all-cause mortality (relative risk (RR) 0.72, 95% confidence interval (CI) 0.49-1.06; 4 trials; 359 participants; I2 = 0%; TSA-adjusted CI 0.15-3.48; very low certainty of evidence). Fewer serious adverse events were registered in the group treated with loop diuretics (RR 0.81, 95% CI 0.66-0.99; 6 trials; 476 participants; I2 = 0%; very low certainty of evidence), though contested by TSA (TSA-adjusted CI 0.55-1.20).

CONCLUSIONS

The evidence is very uncertain about the effect of loop diuretics on mortality and serious adverse events in adult ICU patients with fluid overload. Loop diuretics may reduce the occurrence of these outcomes, but large randomised placebo-controlled trials at low risk of bias are needed.

Effects of the Type of Intraoperative Fluid in Living Donor Kidney Transplantation: A Single-Center Retrospective Cohort Study

PURPOSE

Perioperative fluid management in kidney transplant recipients is crucial to supporting the fluid, acid-base, and electrolyte balance required for graft perfusion. However, the choice of intraoperative crystalloids in kidney transplantation remains controversial. We conducted a single-center retrospective cohort study to evaluate the impact of intraoperative fluids on acid-base and electrolyte balance and graft outcomes.

MATERIALS AND METHODS

We included 282 living donor kidney transplant recipients from January 2010 to December 2017. Patients were classified into two groups based on the type of intraoperative crystalloids used (157 patients in the half saline group and 125 patients in the balanced crystalloid solutions group, Plasma-lyte).

RESULTS

Compared with the half saline group, the Plasma-lyte group showed less metabolic acidosis and hyponatremia during surgery. Hyperkalemia incidence was not significantly different between the two groups. Changes in postoperative graft function assessed by blood urea nitrogen and creatinine were significantly different between the two groups. Patients in the Plasma-lyte group exhibited consistently higher glomerular filtration rates than those in the half saline group at 1 month and 1 year after transplantation after adjusting for demographic differences.

CONCLUSION

Intraoperative Plasma-lyte can lead to more favorable results in terms of acid-base balance during kidney transplantation. Patients who received Plasma-lyte showed superior postoperative graft function at 1 month and 1 year after transplantation. Further studies are needed to evaluate the superiority of intraoperative Plasma-lyte over other types of crystalloids in relation to graft outcomes.

Influence of the trajectory of the urine output for 24 h on the occurrence of AKI in patients with sepsis in intensive care unit

BACKGROUND

Sepsis-associated acute kidney injury (S-AKI) is a common and life-threatening complication in hospitalized and critically ill patients. This condition is an independent cause of death. This study was performed to investigate the correlation between the trajectory of urine output within 24 h and S-AKI.

METHODS

Patients with sepsis were studied retrospectively based on the Medical Information Mart for Intensive Care IV. Latent growth mixture modeling was used to classify the trajectory of urine output changes within 24 h of sepsis diagnosis. The outcome of this study is AKI that occurs 24 h after sepsis. Cox proportional hazard model, Fine-Gray subdistribution proportional hazard model, and doubly robust estimation method were used to explore the risk of AKI in patients with different trajectory classes.

RESULTS

A total of 9869 sepsis patients were included in this study, and their 24-h urine output trajectories were divided into five classes. The Cox proportional hazard model showed that compared with class 1, the HR (95% CI) values for classes 3, 4, and 5 were 1.460 (1.137-1.875), 1.532 (1.197-1.961), and 2.232 (1.795-2.774), respectively. Competing risk model and doubly robust estimation methods reached similar results.

CONCLUSIONS

The trajectory of urine output within 24 h of sepsis patients has a certain impact on the occurrence of AKI. Therefore, in the early treatment of sepsis, close attention should be paid to changes in the patient's urine output to prevent the occurrence of S-AKI.

Acute intensive care unit resuscitation of severely injured trauma patients: Do we need a new strategy?

BACKGROUND

Unlike recent advances in blood product resuscitation, intravenous crystalloid (IVF) use after intensive care unit (ICU) admission in hemorrhagic shock has received less attention and current recommendations are based on limited evidence. To address this knowledge gap, we aimed to determine associations between IVF administration during acute ICU resuscitation and outcomes. We hypothesized that larger IVF volumes are associated with worse outcomes.

METHODS

We linked our trauma registry with electronic health record data (2012-2015) to identify adults with an initial lactate level of ≥4 mmol/L and documented lactate normalization (≤2 mmol/L), excluding those with isolated head Abbreviated Injury Scale score ≥3. We focused on the period from ICU admission to lactate normalization, analyzing duration, volume of IVF, and proportion of volume as 1-L boluses. We used linear regression to determine associations with ICU length of stay and duration of mechanical ventilation in survivors, and logistic regression to identify associations with acute kidney injury and home discharge while adjusting for important covariates.

RESULTS

We included 337 subjects. Median time to lactate normalization was 15 hours (interquartile range, 7-25 hours), and median IVF volume was 3.7 L (interquartile range, 1.5-6.4 L). The fourfold difference between the upper and lower quartiles of both duration and volume remained after stratifying by injury severity. Hourly volumes tapered over time but persistently aggregated at 0.5 and 1 L, with 167 subjects receiving at least one 0.5-L bolus for 6 hours after ICU admission. Administration of larger volumes was associated with longer ICU length of stay and duration of mechanical ventilation, as well as acute kidney injury.

CONCLUSION

There is substantial variation in volume administered during acute ICU resuscitation, both absolutely and temporally, despite accounting for injury severity. Administration of larger volumes during acute ICU resuscitation is associated with worse outcomes. There is an opportunity to improve outcomes by further investigating and standardizing this important phase of care.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Nephrotoxicity in Neonates

Acute kidney injury (AKI) is classified based on prerenal, intrinsic, and postrenal causes. In the newborn, AKI can occur after an insult during the prenatal, perinatal, or postnatal period. AKI is usually an underrecognized condition and its true incidence is unknown. AKI may result from the administration of a number of different nephrotoxic medications, which are often used concurrently in critically ill neonates, exponentially increasing the risk of renal injury. Drug toxicity may also compromise the formation and development of nephrons, and this is particularly important in preterm infants, who have incomplete nephrogenesis. Little is known about the pharmacokinetics and pharmacodynamics of different medications used in neonates, especially for the most immature infant, and the use of most medications in this population is off label. Strategies to prevent AKI include the avoidance of hypotension, hypovolemia, fluid imbalances, hypoxia, and sepsis as well as judicious use of nephrotoxic medications. Treatment strategies aim to maintain fluids and electrolytic and acid-base homeostasis, along with an adequate nutritional status. Neonates are especially prone to long-term sequelae of AKI and benefit from long-term follow-up. This review summarizes the most relevant aspects of nephrotoxicity in neonates and describes the prevention, treatment, and follow-up of AKI in neonates.

Nephrologist Interventions to Avoid Kidney Replacement Therapy in Acute Kidney Injury

BACKGROUND

Based on the pathophysiology of acute kidney injury (AKI), it is plausible that certain early interventions by the nephrologist could influence its trajectory. In this study, we investigated the impact of 5 early nephrology interventions on starting kidney replacement therapy (KRT), AKI progression, and death.

METHODS

In a prospective cohort at the Hospital Civil of Guadalajara, we followed up for 10 days AKI patients in whom a nephrology consultation was requested. We analyzed 5 early interventions of the nephrology team (fluid adjustment, nephrotoxic withdrawal, antibiotic dose adjustment, nutritional adjustment, and removal of hyperchloremic solutions) after the propensity score and multivariate analysis for the risk of starting KRT (primary objective), AKI progression to stage 3, and death (secondary objectives).

RESULTS

From 2017 to 2020, we analyzed 288 AKI patients. The mean age was 55.3 years, 60.7% were male, AKI KDIGO stage 3 was present in 50.5% of them, sepsis was the main etiology 50.3%, and 72 (25%) patients started KRT. The overall survival was 84.4%. Fluid adjustment was the only intervention associated with a decreased risk for starting KRT (odds ratio [OR]: 0.58, 95% confidence interval [CI]: 0.48-0.70, and p ≤ 0.001) and AKI progression to stage 3 (OR: 0.59, 95% CI: 0.49-0.71, and p ≤ 0.001). Receiving vasopressors and KRT were associated with mortality. None of the interventions studied was associated with reducing the risk of death.

CONCLUSIONS

In this prospective cohort study of AKI patients, we found for the first time that early nephrologist intervention and fluid prescription adjustment were associated with lower risk of starting KRT and progression to AKI stage 3.

Assessment of Fluid Status by Bioimpedance Analysis and Central Venous Pressure Measurement and Their Association with the Outcomes of Severe Acute Kidney Injury

Background and Objectives: Fluid disbalance is associated with adverse outcomes in critically ill patients with acute kidney injury (AKI). In this study, we intended to assess fluid status using bioimpedance analysis (BIA) and central venous pressure (CVP) measurement and to evaluate the association between hyperhydration and hypervolemia with the outcomes of severe AKI. Materials and Methods: A prospective study was conducted in the Hospital of the Lithuanian University of Health Sciences Kauno Klinikos. Forty-seven patients treated at the Intensive Care Unit (ICU) with severe AKI and a need for renal replacement therapy (RRT) were examined. The hydration level was evaluated according to the ratio of extracellular water to total body water (ECW/TBW) of bioimpedance analysis and volemia was measured according to CVP. All of the patients were tested before the first hemodialysis (HD) procedure. Hyperhydration was defined as ECW/TBW > 0.39 and hypervolemia as CVP > 12 cm H₂O. Results: According to bioimpedance analysis, 72.3% (n = 34) of patients were hyperhydrated. According to CVP, only 51.1% (n = 24) of the patients were hypervolemic. Interestingly, 69.6% of hypovolemic/normovolemic patients were also hyperhydrated. Of all study patients, 57.4% (n = 27) died, in 29.8% (n = 14) the kidney function improved, and in 12.8% (n = 6) the demand for RRT remained after in-patient treatment. A tendency of higher mortality in hyperhydrated patients was observed, but no association between hypervolemia and outcomes of severe AKI was established. Conclusions: Three-fourths of the patients with severe AKI were hyperhydrated based on bioimpedance analysis. However, according to CVP, only half of these patients were hypervolemic. A tendency of higher mortality in hyperhydrated patients was observed.

Effect of positive cumulative fluid balance on postoperative complications after living donor liver transplantation: A retrospective analysis

Background and Aims:

Fluid administration during liver transplant (LT) surgery is controversial. Although adverse outcomes following positive intraoperative fluid balance have been reported, studies presenting the influence of cumulative postoperative fluid balance (CFB) on complications following LT are sparse. Patients with chronic liver disease tend to receive more fluid during and after surgery due to their unique physiological disease state. The aim of this study was to evaluate the influence of 48-hour CFB on the development of acute kidney injury (AKI) and pulmonary complications on day 4 after live donor LT.

Methods:

This retrospective study included 230 patients undergoing live donor LT. The effect of CFB on day 2 on AKI and pulmonary complications was analysed. Chi-square test, Fisher's exact test, samples t-test, Mann-Whitney U-test were used.

Results:

Bivariate analysis showed a lower graft vs recipient weight ratio (GRWR), sepsis (P < 0.001) and a higher 48-hour CFB after surgery significantly increased the development of AKI. For pulmonary complications, higher Model for End- stage Liver Disease-Na(MELD-Na) score, higher peak arterial lactate, higher 48-hour CFB (P = 0.016) and sepsis (P = 0.003) were found to be statistically significant. Upon multivariate analysis, CFB at 48 hours was significantly higher in patients suffering from pulmonary complications, and GRWR and sepsis were significant for AKI. For every one litre increase in CFB on day 2, the odds of pulmonary complications increased by 37%.

Conclusion:

A more positive CFB on day 2 increased the development of pulmonary complications and lower GRWR and sepsis increased the development of AKI.

Fluid management in patients with acute kidney injury - A post-hoc analysis of the FINNAKI study

PURPOSE

Whether positive fluid balance among patients with acute kidney injury (AKI) stems from decreased urine output, overzealous fluid administration, or both is poorly characterized.

MATERIALS AND METHODS

This was a post hoc analysis of the prospective multicenter observational Finnish Acute Kidney Injury study including 824 AKI and 1162 non-AKI critically ill patients.

RESULTS

We matched 616 AKI (diagnosed during the three first intensive care unit (ICU) days) and non-AKI patients using propensity score. During the three first ICU days, AKI patients received median [IQR] of 11.4 L [8.0-15.2]L fluids and non-AKI patients 10.2 L [7.5-13.7]L, p < 0.001 while the fluid output among AKI patients was 4.7 L [3.0-7.2]L and among non-AKI patients 5.8 L [4.1-8.0]L, p < 0.001. In AKI patients, the median [IQR] cumulative fluid balance was 2.5 L [-0.2-6.0]L compared to 0.9 L [-1.4-3.6]L among non-AKI patients, p < 0.001. Among the 824 AKI patients, smaller volumes of fluid input with a multivariable OR of 0.90 (0.88-0.93) and better fluid output (multivariable OR 1.12 (1.07-1.18)) associated with enhanced change of resolution of AKI.

CONCLUSIONS

AKI patients received more fluids albeit having lower fluid output compared to matched critically ill non-AKI patients. Smaller volumes of fluid input and higher fluid output were associated with better AKI recovery.

Timing of continuous renal replacement therapy in severe acute kidney injury patients with fluid overload: A retrospective cohort study

PURPOSE

We aimed to evaluate the association of early versus late initiation of Continuous renal replacement therapy (CRRT) with mortality in patients with fluid overload.

METHODS

This was a retrospective cohort study of patients with fluid overload (FO) treated with CRRT due to severe acute kidney injury (AKI) between January 2015 and December 2017 in a mixed medical intensive care unit of a teaching hospital in Beijing, China. Patients were divided into early (≤15 h) and late (>15 h) groups based on the median time from ICU admission to CRRT initiation. The primary outcome was all-cause mortality at day 60. Multivariable Cox model analysis was used for analysis.

RESULTS

The study patients were male predominant (84/150) with a mean age of 64.8 ± 16.7 years. The median FO value before CRRT initiation was 10.1% [6.2-16.1%]. The 60-day mortality rates in the early vs the late CRRT groups were 53.9% and 73%, respectively. On multivariable Cox modelling, the late initiation of CRRT was independently associated with an increased risk of death at 60 days (HR 1.75, 95% CI 1.11-2.74, p = 0.015).

CONCLUSIONS

Early initiation of CRRT was independently associated with survival benefits in severe AKI patients with fluid overload.

Hemodynamically stable oliguric patients usually do not respond to fluid challenge

Objective

To evaluate renal responsiveness in oliguric critically ill patients after a fluid challenge.

Methods

We conducted a prospective observational study in one university intensive care unit. Patients with urine output < 0.5mL/kg/h for 3 hours with a mean arterial pressure > 60mmHg received a fluid challenge. We examined renal fluid responsiveness (defined as urine output > 0.5mL/kg/h for 3 hours) after fluid challenge.

Results

Forty-two patients (age 67 ± 13 years; APACHE II score 16 ± 6) were evaluated. Patient characteristics were similar between renal responders and renal nonresponders. Thirteen patients (31%) were renal responders. Hemodynamic or perfusion parameters were not different between those who did and those who did not increase urine output before the fluid challenge. The areas under the receiver operating characteristic curves were calculated for mean arterial pressure, heart rate, creatinine, urea, creatinine clearance, urea/creatinine ratio and lactate before the fluid challenge. None of these parameters were sensitive or specific enough to predict reversal of oliguria.

Conclusion

After achieving hemodynamic stability, oliguric patients did not increase urine output after a fluid challenge. Systemic hemodynamic, perfusion or renal parameters were weak predictors of urine responsiveness. Our results suggest that volume replacement to correct oliguria in patients without obvious hypovolemia should be done with caution.

Systematic review on estimated rates of nephrotoxicity and neurotoxicity in patients treated with polymyxins

BACKGROUND

Nephrotoxicity and neurotoxicity are commonly associated with polymyxin treatment; however, the emergence of multidrug-resistant Gram-negative bacteria with limited therapeutic options has resulted in increased use of polymyxins.

OBJECTIVES

To determine the rates of nephrotoxicity and neurotoxicity during polymyxin treatment and whether any factors influence these.

DATA SOURCES

Medline, Embase and Cochrane Library databases were searched on 2 January 2020.

STUDY ELIGIBILITY CRITERIA

Studies reporting nephrotoxicity and/or neurotoxicity rates in patients with infections treated with polymyxins were included. Reviews, meta-analyses and reports not in English were excluded.

PARTICIPANTS

Patients hospitalized with infections treated with systemic or inhaled polymyxins were included. For comparative analyses, patients treated with non-polymyxin-based regimens were also included.

METHODS

Meta-analyses were performed using a random-effects model; subgroup meta-analyses were conducted where data permitted using a mixed-effects model.

RESULTS

In total, 237 reports of randomized controlled trials, cohort and case-control studies were eligible for inclusion; most were single-arm observational studies. Nephrotoxic events in 35,569 patients receiving polymyxins were analysed. Overall nephrotoxicity rate was 0.282 (95% confidence interval (CI) 0.259-0.307). When excluding studies where >50% of patients received inhaled-only polymyxin treatment or nephrotoxicity assessment was by methods other than internationally recognized criteria (RIFLE, KDIGO or AKIN), the nephrotoxicity rate was 0.391 (95% CI 0.364-0.419). The odds of nephrotoxicity were greater with polymyxin therapies compared to non-polymyxin-based regimens (odds ratio 2.23 (95% CI 1.58-3.15); p < 0.001). Meta-analyses showed a significant effect of polymyxin type, dose, patient age, number of concomitant nephrotoxins and use of diuretics, glycopeptides or vasopressors on the rate of nephrotoxicity. Polymyxin therapies were not associated with a significantly different rate of neurotoxicity than non-polymyxin-based regimens (p 0.051). The overall rate of neurotoxicity during polymyxin therapy was 0.030 (95% CI 0.020-0.043).

CONCLUSIONS

Polymyxins are associated with a higher risk of nephrotoxicity than non-polymyxin-based regimens.

Urinary clusterin and cystatin B as biomarkers of tubular injury in dogs following envenomation by the European adder

Diagnosing acute kidney injury remains a challenge since the established renal biomarkers, serum creatinine (sCr) and symmetric dimethylarginine (SDMA) reflect glomerular function and not tubular injury. Sensitive tubular markers such as urinary clusterin (uClust) and cystatin B (uCysB) have been proposed to detect AKI at an earlier stage. Since envenomation by the European adder (Vipera berus berus) could serve as a spontaneous disease model of AKI we investigated these new biomarkers in affected dogs. Concentrations of uClust and uCysB as well as sCr and SDMA were analyzed retrospectively in stored samples from 26 dogs with snake envenomation and 13 healthy controls. Higher concentrations of uClust (P < 0.012) and uCysB (P < 0.001) were observed in the snake-envenomed group. Normalization of uClust and uCysB to urinary creatinine did not alter the results. No differences were observed in sCr and SDMA between the snake-envenomed group and the healthy control group. Spearman rank correlation analysis revealed a strong association of uClust with uCysB in the snake-envenomed dogs (r = 0.75 P < 0.001) but not in the healthy controls. The high percentage of snake-envenomed dogs with increased uClust and uCysB concentrations in the absence of increased sCr and SDMA suggests renal tubular injury in the affected dogs. Larger prospective case-controlled studies are warranted to evaluate the clinical utility and prognostic value of these biomarkers.

Caudal vena cava collapsibility index as a tool to predict fluid responsiveness in dogs

OBJECTIVE

To evaluate the use of the caudal vena cava collapsibility index (CVCCI) as a predictor of fluid responsiveness in hospitalized, critically ill dogs with hemodynamic or tissue perfusion abnormalities.

DESIGN

Retrospective observational study.

SETTING

Private referral center.

ANIMALS

Twenty-seven critically ill, spontaneously breathing dogs with compromised hemodynamics or tissue hypoperfusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The electronic medical records were searched for dogs admitted for any cause, from August 2016 to December 2017. We included dogs with ultrasound measurements of: CVCCI, performed at baseline; and velocity time integral (VTI) of the subaortic blood flow, carried out before and after a fluid load. CVCCI was estimated as: (maximum diameter-minimum diameter/maximum diameter) × 100. Dogs in which VTI increased ≥15% were considered fluid responders. The CVCCI accurately predicted fluid responsiveness with an area under the receiver operating characteristic curve of 0.96 (95% CI, 0.88 to 1.00). The optimal cut-off of CVCCI that better discriminated between fluid responders and nonresponders was 27%, with 100.0% sensitivity and 83.3% specificity. At baseline, fluid responders had lower VTI (5.48 [4.26 to 7.40] vs 10.61 [7.38 to 13.23] cm, P = 0.004) than nonresponders. The basal maximum diameter of the caudal vena cava adjusted to body weight was not different between responders and nonresponders (0.050 [0.030 to 0.100] vs 0.079 [0.067 to 0.140] cm/kg, P = 0.339). The increase in VTI was related to basal CVCCI (R = 0.60, P = 0.001). Bland-Altman analysis showed narrow 95% limits of agreement between measurements of CVCCI and VTI performed by different observers or by the same observer.

CONCLUSIONS

The results of this small cohort study suggest that CVCCI can accurately predict fluid responsiveness in critically ill dogs with perfusion abnormalities. Further research is necessary to extrapolate these results to larger populations of hospitalized dogs.

Loop diuretics in adult intensive care patients with fluid overload: A protocol for a systematic review of randomised clinical trials with meta-analysis and Trial Sequential Analysis

BACKGROUND

In the intensive care unit, fluid overload is frequent and a risk factor for organ dysfunction and increased mortality. Primarily, lung and kidney functions may be impaired by fluid overload resulting in acute respiratory failure and acute kidney injury. No clinical guidelines exist for treatment of fluid overload in intensive care patients. Loop diuretics, most often furosemide, appear to be the most frequently used pharmacological intervention. The aim of this protocol is to describe the methods of a systematic review assessing the evidence of treatment with loop diuretics in adult intensive care patients with fluid overload.

METHODS

We will conduct a systematic review with meta-analysis and report it according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statements, use the recommendations of the Cochrane Handbook and assess the quality of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. We will include randomised clinical trials identified through searches of major international databases and trial registers. Two authors will independently screen and select trials for inclusion, extract data and assess the methodological quality using the Cochrane risk of bias tool. Extracted data will be analysed using Review Manager and Trial Sequential Analysis. The protocol is registered at PROSPERO.

DISCUSSION

We aim to provide reliable evidence on the use of loop diuretics in adult intensive care patients with fluid overload to guide clinicians, decision makers and trialists on clinical practice.

Effect of cumulative fluid balance on acute kidney injury and patient outcomes after orthotopic liver transplantation: A retrospective cohort study

AIM

Acute kidney injury (AKI) is a serious complication following orthotopic liver transplantation (OLT) and it affects long-term patient survival. The aims of this study were to identify the effects of cumulative fluid balance (FB) on early post-OLT AKI and adverse outcomes and to construct a model to predict AKI.

METHODS

We retrospectively analysed 146 adult patients who underwent OLT. AKI severity was classified according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Univariate and multivariate logistic regression analyses were used to evaluate the association between cumulative FB and post-OLT AKI. The Kaplan-Meier method was used to estimate the survival rate.

RESULTS

Within the perioperative period of 72 hours, 50% (66/132) of patients developed AKI, with 36 (54%), 16 (24%) and 14 (21%) patients having AKI stages 1, 2 and 3, respectively. The cumulative FB was the risk factors for post-OLT AKI (odds ratio [OR], 1.011; 95% confidence interval [CI], 1.156~6.001; P = .021). Preoperative albumin was a protective factor for post-OLT AKI (OR, 0.309; 95% CI, 0.140~0.731; P = .007). The AKI group requires renal replacement therapy (RRT) more (15.2% vs 0%, P = .001) and associated with postoperative complications (56% vs 28.8%, P = .003). The complication-free survival was lower in the AKI group ([11.90 vs 18.74] months, χ² = 9.60, P = .002).

CONCLUSION

Cumulative FB within 72 hours is associated with post-OLT AKI and requires RRT. Cumulative FB impacts the long-term complication-free survival of the recipients.

Fluid Overload and Risk of Mortality in Critically Ill Patients

BACKGROUND

Fluid overload (FO) is a condition present in critical care units, and it is associated with clinical complications and worse outcomes for severe patients.

OBJECTIVE

The aim of this study was to verify if FO is a risk factor for mortality in critically ill patients.

METHODS

Retrospective study performed in a Brazilian intensive care unit, from January to March 2016, with patients older than 18 years and hospitalized for more than 24 hours. Demographic and clinical data, as well as fluid balance and overload, were analyzed to verify the risk factors for mortality. A logistic regression model was elaborated, and significance was set at P < .05.

RESULTS

There were 158 patients included, of which only 13 (8.2%) presented FO. Mortality was verified in individuals 30 (18.9%), of whom only 7 (23.3%) developed FO, which was lower in survivors 6 (4.9%), P = .001. In the simple regression model, the FO was significant (odds ratio [OR], 6.23; 95% confidence interval [CI], 2.04-19.53), P = .001. However, in the multiple regression model, there were significant findings only for mechanical ventilation (OR, 5.86; 95% CI, 2.10-18.12, P = .001), acute kidney injury (OR, 4.05; 95% CI, 1.53-11; P = .001), and noradrenaline (OR, 3.85; 95% CI, 1.01-9.51; P = .041); FO was not significant (OR, 3.68; 95% CI, 0.91-15.55; P = .069).

CONCLUSION

Fluid overload is higher in patients who died. Therefore, it was not considered a risk factor for mortality.

Fluid Overload and Acute Kidney Injury

Commonest intervention in hospitalized patient is fluid therapy, and practically every critically ill patient receives fluid resuscitation. Commonest indication for fluid administration is to achieve hemodynamic stability and prevent or manage acute kidney injury (AKI). However, fluid administration is a two-edged sword, i.e., inadequate fluids give rise to hypoperfusion and organ injury and overzealous fluid therapy can give rise to fluid overload and related consequences. Though fluids are commonly given to prevent development of AKI, hypervolemia itself has the potential to cause AKI.

Latent Trajectories of Fluid Balance Are Associated With Outcomes in Cardiac and Aortic Surgery

BACKGROUND

Fluid overload is common in critically ill patients and is associated with worse outcomes. The trends in fluid balance have not been investigated previously. This study used trajectory analysis to investigate the impact of fluid balance trends on patients who had undergone cardiac or aortic surgery.

METHODS

We analyzed patients who underwent cardiac or aortic surgery between August 2005 and March 2015. We excluded patients who died within the first 72 postoperative hours or received chronic dialysis before the surgery. Trajectories of urine and input-output during the first 3 postoperative days were analyzed using a latent class growth model. The primary outcomes were any stage of acute kidney injury (AKI) by Kidney Disease Improving Global Outcomes definition and de novo dialysis.

RESULTS

The in-hospital mortality was 6.6% (70 of the 1063 patients included). The fluid input-output balance trajectories had better association with the primary outcome than urine output trajectories did. The risk of AKI and de novo dialysis were highest in the group with progressively positive fluid balance adjusted by preoperative body weight (AKI: adjusted odds ratio, 7.10; 95% confidence interval, 2.02-24.93; de novo dialysis: odds ratio, 4.54; 95% confidence interval, 1.12-18.38).

CONCLUSIONS

A progressively positive fluid balance is associated with AKI and de novo dialysis in patients undergoing cardiac or aortic surgery.

Acute Kidney Injury and Fluid Resuscitation in Septic Patients: Are We Protecting the Kidney?

Acute kidney injury (AKI) is a common complication in critically ill patients, especially among septic patients. Sepsis and hypovolemia are the 2 most frequent etiologies of AKI in intensive care units and frequently coexist in critically ill patients. Effective fluid resuscitation is crucial for the stabilization of sepsis-induced tissue hypoperfusion or septic shock. However, the lack of a goal-directed therapy targeting kidney oxygenation prevents from optimization of the fluid therapy with regard to improvement of renal oxygen delivery and extraction. Similarly, fluid administration as all therapeutic actions carries adverse effects such as the activation of cytokines, disruption of the capillary glycocalyx, and adverse effects on kidney metabolism and oxygenation. Moreover, a positive fluid balance is associated with an increased risk of AKI and is a negative predictor for recovery of renal function. The role of fluid resuscitation on kidney injury stems from the high renal vulnerability to hypoxemic injury. Indeed, fluids have a poor oxygen solubility and hemodilution decreases blood viscosity both promoting intrarenal shunting and heterogeneity with a decreased capillary density and enhanced intrarenal cortex and medullary hypoxia. The development of physiological biomarkers that are able to detect the early development of AKI specifically aimed at the identification of renal microcirculatory dysfunctions should form a valuable contribution to monitoring therapeutic modalities.

Factors associated with acute kidney injury in acute respiratory distress syndrome

Background

Acute kidney injury (AKI) is the most frequent extra-pulmonary organ failure in acute respiratory distress syndrome (ARDS). The objective of this study was to assess the factors associated with the development and severity of AKI in patients with ARDS.

Methods

This is a retrospective cohort study of ARDS patients without acute or chronic kidney disease prior to the onset of ARDS over a 7-year period (2010–2017). AKI and severity of AKI were defined according to the Kidney Disease Improving Global Outcomes 2012 guidelines.

Results

Of the 634 ARDS patients, 357 patients met study criteria. A total of 244 (68.3%) patients developed AKI after ARDS onset: 60 (24.6%) had stage I AKI, 66 (27%) had stage II AKI, and 118 (48.4%) had stage III AKI. The median time of AKI onset for stage I AKI was 2 days (interquartile range, 1.5–5.5) while stage II and III AKI was 4 days. On multivariable analysis, factors associated with development of AKI were age [subdistribution hazard ratio (SHR) 1.01, 95% confidence interval (CI) 1.00–1.02], SOFA score (SHR 1.16, 95%CI 1.12–1.21), a history of diabetes mellitus (DM) (SHR 1.42, 95%CI 1.07–1.89), and arterial pH on day 1 of ARDS (SHR per 0.1 units decrease was 1.18, 95%CI 1.05–1.32). In severity of AKI, stage I AKI was associated with age (SHR 1.03, 95%CI 1.01–1.05) and serum bicarbonate on day 1 of ARDS (SHR 1.07, 95%CI 1.02–1.13). Stage II AKI was associated with age (SHR 1.03, 95%CI 1.01–1.05), serum bicarbonate on day 1 (SHR 1.12, 95%CI 1.06–1.18), SOFA score (SHR 1.19, 95%CI 1.10–1.30), history of heart failure (SHR 3.71, 95%CI 1.63–8.46), and peak airway pressure (SHR 1.04, 95%CI 1.00–1.07). Stage III AKI was associated with a higher BMI (SHR 1.02, 95%CI 1.00–1.03), a history of DM (SHR 1.79, 95%CI 1.18–2.72), SOFA score (SHR 1.29, 95%CI 1.22–1.36), and arterial pH on day 1 (SHR per 0.1 units decrease was 1.25, 95%CI 1.05–1.49).

Conclusions

Age, a higher severity of illness, a history of diabetes, and acidosis were associated with development of AKI in ARDS patients. Severity of AKI was further associated with BMI, history of heart failure, and peak airway pressure.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0552-5) contains supplementary material, which is available to authorized users.

Science and fiction in critical care: established concepts with or without evidence?

In the absence of evidence, therapies are often based on intuition, belief, common sense or gut feeling. Over the years, some treatment strategies may become dogmas that are eventually considered as state-of-the-art and not questioned any longer. This might be a reason why there are many examples of "strange" treatments in medical history that have been applied in the absence of evidence and later abandoned for good reasons.In this article, five dogmas relevant to critical care medicine are discussed and reviewed in the light of the available evidence. Dogma #1 relates to the treatment of oliguria with fluids, diuretics, and vasopressors. In this context, it should be considered that oliguria is a symptom rather than a disease. Thus, once hypovolaemia can be excluded as the underlying reason, there is no justification for giving fluids, which may do more harm than good in euvolaemic or hypervolaemic patients. Similarly, there is no solid evidence for forcing diuresis by administering vasopressors and loop diuretics. Dogma #2 addresses the treatment of crush syndrome patients with aggressive fluid therapy using NaCl 0.9%. In fact, this treatment may aggravate renal injury by iatrogenic metabolic acidosis and subsequent renal hypoperfusion. Dogma #3 concerns the administration of NaCl 0.9% to patients undergoing kidney transplantation. Since these patients are usually characterised by hyperkalaemia, the potassium-free solution NaCl 0.9%, containing exclusively 154 mmol/l of sodium and chloride ions each, is often considered as the fluid of choice. However, large volumes of chloride-rich solutions cause hyperchloraemic acidosis in a dose-dependent manner and induce a potassium shift to the extracellular space, thereby increasing serum potassium levels. Thus, balanced electrolyte solutions are to be preferred in this setting. Dogma #4 relates to the fact that enteral nutrition is often withheld for patients with high residual gastric volume due to the theoretical risk of gastro-oesophageal reflux, potentially resulting in aspiration pneumonitis. Despite controversial discussions, there is no clinical data supporting that residual gastric volume should be generally measured, especially not in patients without a gastro-intestinal surgery and/or motility disorders. Clinical evidence rather suggests that abandoning residual gastric volume monitoring does not increase the incidence of pneumonia, but may benefit patients by facilitating adequate enteral feeding. Finally, dogma #5 is about sedating all mechanically ventilated patients because "fighting" against the respirator may cause insufficient ventilation. This concern needs to be balanced against the unwanted consequences of sedation, such as prolonged mechanical ventilation and intensive care unit length of stay as well as increased risk of delirium. Modern concepts based on adequate analgesia and moderate to no sedation appear to be more suitable.In conclusion, dogmas are still common in clinical practice. Since science rather than fiction should govern our actions in intensive care medicine, it is important to remain critical and challenge long established concepts, especially when the underlying evidence is weak or non-existing.

Nonischemic Causes of Cardiogenic Shock

Although cardiogenic shock is uncommon in the emergency department, it is associated with high mortality. Most cardiogenic shock is caused by ischemia, but nonischemic etiologies are essential to recognize. Clinicians should optimize preload, contractility, and afterload. Volume-responsive patients should be resuscitated in small aliquots, although some patients may require diuresis to improve cardiac output. Vasopressors are important to restore end-organ perfusion, and inotropes improve contractility. Intubation and positive pressure ventilation impact hemodynamics, which, depending on volume status, may be beneficial or deleterious. Knowing indications for mechanical circulatory support is important for timely consultation or transfer as indicated.

Lung Ultrasound Guided Fluid Management Protocol for the Critically Ill Patient: study protocol for a multi-centre randomized controlled trial

Background

In routine intensive care unit (ICU) practice, fluids are often administered without a safety limit, which may lead to fluid overload and decreased survival. Recently, B-lines score (BLS) has been validated as a lung ultrasound (LUS) quantification of pulmonary congestion. This suggests that LUS may provide a safety threshold to conduct fluid therapy and to avoid overhydration. However, there is no randomized study to test the utility of LUS in guiding fluid management in ICU patients by using a pre-specified BLS cut-off value as a threshold for fluid removal.

Methods

LUS Guided Fluid Management Protocol for the Critically Ill Patient is a prospective, multi-centre, randomized controlled trial. Five hundred ICU patients will be randomly assigned in a 1:1 ratio, to protocolized LUS-based fluid management or usual care. The trial intervention will start on ICU admission and will consist in daily assessment of BLS and triggered evacuation of excessive fluids with loop diuretics (Furosemide) when BLS ≥ 15. If rebalancing volume status with diuretics fails, forced evacuation by ultrafiltration will be used. The main endpoint is death from all causes at 28 days from randomization. The secondary outcomes are presence and time-course evolution of organ dysfunctions, ICU- and hospital length of stay, all-cause mortality at 90 days, and health economics data.

Discussion

If study results will show that LUS guided fluid management protocol improves outcome in ICU patients, it will be the base for other studies to refine this protocol or track those categories of critically ill patients to whom it may bring maximum benefits.

Trial registration

ClinicalTrials.gov, NCT03393065. Registered on 8 January 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3345-0) contains supplementary material, which is available to authorized users.

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.

The Ability of Polyuria in Prediction of Weaning Outcome in Critically Ill Mechanically Ventilated Patients

BACKGROUND

Fluid balance and oliguria influence outcome in critically ill patients. Although, osmotic dieresis with hypernatraemia is a predictor of mortality in critically ill patients, the purpose of this study was to demonstrate the effect of polyuria as an independent predictor on weaning outcome in mechanically ventilated patients.

MATERIALS AND METHODS

This retrospective, single center, cohort study was carried out at Imam Teaching Hospital Intensive Care Unit (ICU) on 263 adult mechanically ventilated patients. We collected data of these patients during the mean seven consecutive days before weaning from mechanical ventilator. Patients with polyuria (sustained urine output greater than 3000 ml/day) were compared with patients without polyuria. The primary endpoint was successful weaning and the secondary endpoints were the mechanical ventilation duration, post weaning length of ICU stay, post weaning length of hospitalization and rate of mortality.

RESULTS

In 93 patients with polyuria, the mean age was 45.14±19.47 years in comparison of 170 patients without polyuria with mean age of 52.9±21.37 years (P=0.004). Fluid intake, urine output and temperature were significantly higher in patients with polyuria, but there were no statistical differences in systolic and diastolic blood pressure, serum electrolytes, urea and creatinine. No significant differences were found in primary and secondary endpoints including successful weaning, post weaning length of ICU stay, post weaning hospital duration and mortality, except for duration of mechanical ventilation (P=0.014). The area under the ROC curve for variables showed only seven days mean creatinine level before weaning which may act as a predictor of successful weaning (ROCAUC=0.67, 95% CI 0.61-0.73, P=0.0002). Serum creatinine level of 0.8 provided best overall combination of sensitivity and specificity for successful weaning (sensitivity 72.22%, 95% CI 54.8-85.8; specificity 61.19%, 95% CI 54.1-68.0).

CONCLUSION

Polyuria cannot predict weaning outcome but maybe considered as a predictor of longer duration of mechanical ventilation and is probably associated with a subclinical renal dysfunction.

Euvolemia-A critical target in the management of acute kidney injury

It has been clearly established that critically ill patients with sepsis require prompt fluid resuscitation. The optimal amount of fluid and when to taper this resuscitation is less clear. There is a growing evidence that fluid overload leads to acute kidney injury, and increased morbidity and mortality. A clinician's best intentions in resuscitating a patient can lead to too much of a good thing. Currently, there are several bedside tools to aid in determining a patient's response to a fluid challenge as well as in the assessment of the current volume status. Guidelines are not available on the exact rate of fluid overload removal and what medicinal or mechanical modality is most favorable. We discuss our experience and an examination of the literature on the problems with fluid overload, and how a patient may benefit from forced fluid removal.