Mechanisms for hemodynamic instability related to renal replacement therapy: a narrative review

Water treatment-free prolonged intermittent kidney replacement therapy: A new approach for kidney replacement therapy in the ICU setting. A retrospective study

The optimal modalities of kidney replacement therapy (KRT) in the ICU remain debated. Intermittent haemodialysis (IHD) and continuous veno-venous haemofiltration (CVVH) are the two main methods. Intermittent haemodialysis requires a water treatment system, which may not be available in all jurisdictions. We report the experience of an innovative strategy of intermittent KRT without water treatment system. Based on the manufacturer's recommendations, the dialysate flow during "CVVHDF post" (post-dilution continuous veno-venous haemodiafiltration) mode was increased by connecting the substitution pump in parallel with the dialysate pump using a Y-connector. This doubled the flow rate of dialysate, allowing for 9000 mL/h during intermittent KRT sessions at a blood flow rate of 250 mL/min. We called this technique "water treatment-free prolonged intermittent kidney replacement therapy" (WTF-PIKRT). We report our experience in 18 patients who underwent 88 WTF-PIKRT sessions (median duration 5 h (IQR [4, 6])) between August 2019 and May 2020. The median urea reduction ratio was 38 % (IQR [29,49]). Hypotension occurred during 21.6 % of sessions. Hypokalemia or hypophosphatemia occurred in less than 5 % of sessions. WTF-PIKRT represents an attractive alternative to conventional IHD when a water treatment system is not available. Despite its lower efficacy compared with IHD, it may have significant organizational and economic impact.

Association of vasopressor use during renal replacement therapy and mortality

Among critically ill patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT) whether vasopressor use is associated with outcomes is unclear. We examined the association of vasopressor use following RRT initiation with in-hospital mortality in critically ill adults with AKI requiring different modalities of RRT. This observational study was conducted using the Premier Inc. (PINC) AI Healthcare Database of patients (n = 20,882) in U.S. hospitals with AKI requiring continuous RRT (n = 7660) and intermittent hemodialysis ([IHD], n = 13,222) with discharge from January 1, 2018, to June 30, 2021. Data on vasopressor use 3 days before and 3 days after RRT initiation were extracted. Exposure to vasopressors post-RRT initiation was significantly associated with risk-adjusted in-hospital mortality among patients treated with CRRT (risk-adjusted hazard ratio [aHR], 1.69 95 %CI: 1.55-1.85) and IHD (aHR, 1.72, 95 %CI: 1.61-1.84). There was an incremental risk of death associated with the number of vasopressors. Among CRRT patients, the risk of death were: 1 vasopressor (aHR, 1.50; 95 % CI: 1.36-1.65), 2 vasopressors (aHR, 1.94; 95 % CI: 1.76-2.14), and 3 vasopressors (aHR, 2.06; 95 % CI: 1.72-2.46). Similarly, for IHD patients, the aHRs were: 1 vasopressor (aHR, 1.57; 95 % CI: 1.47-1.68), 2 vasopressors (aHR, 2.20; 95 % CI: 2.02-2.40), and 3 vasopressors (aHR, 2.32; 95 % CI: 1.82-2.96). In summary, vasopressor use during the 3 days post-RRT initiation was independently and incrementally associated with higher in-hospital mortality in patients receiving either CRRT or IHD as the first modality.

Clinical effects of combination therapy with continuous renal replacement therapy and continuous intravenous sodium infusion therapy

INTRODUCTION

This single-center retrospective study investigated the clinical effects of combination therapy involving continuous renal replacement therapy (CRRT) and continuous intravenous sodium infusion therapy (cIVNa) in critically ill patients with prerenal acute kidney injury (AKI) who were expected to experience insufficient plasma refilling.

METHOD

The clinical data of 92 patients were analyzed. Clinical data from the control (CRRT, n = 49) and intervention (CRRT + cIVNa, n = 43) groups were compared statistically.

RESULTS

Combination therapy increased blood pressure and urine volume, while reducing hypotension events, indicating hemodynamic stabilization. Furthermore, it significantly improved the 90-day survival rate (61.9% vs. 38.8%, p < 0.05), 60-day and 90-day survival rates without RRT (59.5% vs. 28.6%, p < 0.01; 54.8% vs. 26.5%, p < 0.01, respectively), survival discharge rate from intensive care unit, CRRT withdrawal rate, and renal replacement therapy withdrawal rate.

CONCLUSION

Combination therapy with continuous renal replacement therapy and continuous intravenous sodium infusion therapy may be a useful treatment option for critically ill patients with prerenal acute kidney injury who require continuous renal replacement therapy.

A pilot feasibility study of continuous cardiac output and blood pressure monitoring during intermittent hemodialysis in patients recovering from severe acute kidney injury

PURPOSE

To detect changes in cardiac output and blood pressure during intermittent hemodialysis (IHD) in patients recovering from severe acute kidney injury (AKI) after transition from continuous renal replacement therapy (CRRT).

MATERIAL AND METHODS

In this single-center pilot feasibility study, we applied continuous hemodynamic monitoring (ClearSight System™) before and during IHD sessions in patients recovering from severe AKI. We also measured relative blood volume (BV; CRIT-LINE®IV) and Net Ultrafiltration Rate (NUF). CI changes were categorized as follows: Increase (>5 %), Stable (-5 % to 5 %), Mild Decrease (-5 % to -15 %), Moderate Decrease (-15 % to -25 %), and Severe Decrease (<-25 %).

RESULTS

We enrolled 10 AKI patients. Overall, there were 119 episodes of severe and 286 episodes of moderate reductions in cardiac index (CI). The median time spent with severe and moderate intradialytic reductions in CI was 8.2 min [2.1-115.8] and 49.5 min [21.6-57.5], respectively. Severe CI reductions happened in nine patients out of 10, and in three patients, they lasted more than 2 h. During IHD, mean arterial pressure increased or remained stable in >78 % of measurements, regardless of changes in CI. Overall, CI decreased by -1.14 L/min/m2 during a moderate BV decrease (p < 0.001) and by -0.57 L/min/m2 when NUF rate was high (p < 0.001).

CONCLUSIONS

CI often, repeatedly, and markedly decreased during IHD. Such decreases were not detected by MAP monitoring and were extreme in some patients.

Effects of colloid versus crystalloid priming on early haemodynamics in critically ill patients receiving CRRT: protocol for a randomised controlled trial

INTRODUCTION

Despite the acknowledged advantage of continuous renal replacement therapy (CRRT) in maintaining stable haemodynamics compared with intermittent haemodialysis, hypotension remains a common complication, affecting up to 43% of patients immediately following CRRT. This issue can precipitate serious adverse events and is associated with increased mortality. The significant reduction in blood volume during the withdrawal process for machine processing, combined with the rapid elimination of urea during purification, can cause a precipitous decline in plasma osmotic pressure, both of which may serve as triggers for early hypotension during CRRT. Currently, conventional strategies, such as priming the pipeline with normal saline combined with double connections, have failed to significantly reduce the incidence of early hypotension. To prevent this complication, some researchers have turned to the use of human albumin, plasma and colloid fluids instead of normal saline for pipeline priming. Nevertheless, evidence favouring this approach over traditional crystalloid priming is still lacking. This study aims to investigate whether colloid priming is superior to crystalloid priming in reducing the incidence of early hypotension and all-cause mortality, as well as shortening the duration of hospitalisation in intensive care unit and reducing the dialysis dependence in critically ill patients undergoing CRRT.

METHODS AND ANALYSIS

A single-centre, prospective, randomised controlled trial will be conducted at West China Hospital of Sichuan University, China. A total of 216 participants who met the inclusion and exclusion criteria will be recruited and divided into either the experimental or control group at a ratio of 1:1 via a central randomisation system. In the experimental group, succinyl gelatin will be used to prime the pipeline prior to the connection with the CRRT machine, whereas the control group will use normal saline. The primary outcome is the incidence of early hypotension during CRRT. The outcome assessors and data analysts will be blinded. All the data will be analysed based on randomly assigned groups unless data for the primary outcomes are missing.

ETHICS AND DISSEMINATION

The trial protocol was approved by the Ethics Review Committee of West China Hospital of Sichuan University (2023.2084), and the results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR2400082835.

Cumulative impact of hypotension during intermittent hemodialysis on kidney recovery in critically ill patients with AKI-D

BACKGROUND

Intermittent hemodialysis (IHD) is commonly implemented in patients with AKI-D, irrespective of the initial kidney replacement therapy (KRT) modality. However, concerns remain regarding the hemodynamic instability during IHD. This study aimed to assess the association between hypotensive episodes during IHD and kidney recovery in AKI-D patients.

METHODS

We retrospectively enrolled AKI-D survivors who received IHD in the intensive care units of a tertiary care hospital in Korea from January 2018 to February 2024.

RESULTS

A total of 1791 IHD sessions from 209 AKI-D survivors were analyzed. The patients underwent a median of 7 IHD sessions (interquartile range [IQR] 3-11), with an incidence of intradialytic hypotension (IDH) of 16.8 % per patient. Of these, 43.1 % were dialysis-dependent at hospital discharge. The number of IDH was a significant predictor of dialysis dependence (odds ratio [OR] 1.56; 95 % confidence interval [CI] 1.16-2.22). Patients experiencing ≥3 IDH episodes had a substantially higher risk of dialysis dependence compared to those without IDH (OR 9.41; 95 % CI 2.41-41.69). In per-session analysis, the target ultrafiltration rate was identified as an independent risk factor for IDH occurrence.

CONCLUSIONS

Our study revealed that IHD-related hypotension during hospitalization has a cumulative negative impact on kidney recovery in AKI-D survivors.

Definitions of Hemodynamic Instability Related to Renal Replacement Therapy in Critically Ill Patients: A Systematic Review Protocol

Background

Hemodynamic instability related to renal replacement therapy (HIRRT) is a common complication affecting critically ill patients that require renal replacement therapy (RRT). There is currently no consensus regarding the definition of HIRRT in critically ill patients. In this context, the impacts of HIRRT on clinical outcomes such as mortality or renal recovery in critically ill patients are unclear.

Objective

The primary objective of this proposed systematic review is to evaluate the association between HIRRT and clinical outcomes, as reported within randomized control trials in the literature. The secondary objective of this systematic review is to compare rates of HIRRT, according to various definitions used by randomized controlled trials, across different RRT modalities used to treat critically ill patients, with the goal of paving the way toward a common definition of HIRRT for future research.

Design

Systematic review and meta-analysis.

Measurements

The rates of HIRRT, mortality, and renal recovery will be reported according to each definition of HIRRT.

Patients

Critically-ill adults with acute kidney injury admitted to intensive care units.

Methods

The search strategy will be developed to identify articles in Medline, MEDLINE In-Process, EMBASE, and Cochrane CENTRAL Registry. We will include randomized control trials examining renal replacement therapy in critically ill patients. This will include intermittent hemodialysis (iHD), all forms of prolonged intermittent RRT (PIRRT), and continuous renal replacement therapy (CRRT). Only articles that report a definition of HIRRT and the rates of HIRRT will be included in our analysis. Two reviewers will independently screen all articles for inclusion and exclusion. Data extraction and quality assessment will be also performed in duplicate. All disagreements will be resolved through discussion or a third reviewer.

Limitations

The heterogeneity in the definitions of HIRRT and outcome reporting may limit the ability to perform meta-analysis and perform comparisons in the rates of HIRRT between RRT modalities.

Conclusions

This systematic review aims to assess the association between HIRRT and important clinical outcomes. In doing so, we will identify definitions of HIRRT within the current literature and the rates of HIRRT associated with these definitions. HIRRT can result in early discontinuation of dialysis, organ injury from hypoperfusion, and may negatively impact mortality and renal recovery in critically ill patients. This systematic review will synthesize the impact and frequency of HIRRT reported in the literature and, in doing so, may help determine the extent to which common definitions of HIRRT might be recommended for standardized use in future research related to HIRRT.

Systematic Review Registration

PROSPERO registration number: CRD42023396550.

Impact of renal replacement therapy modality on coagulation and platelet function in critically ill patients: A prospective observational study

BACKGROUND

Renal replacement therapy (RRT) may affect coagulation and platelet function in critically ill patients. However, the mechanism and the difference in the impact on coagulation between intermittent hemodialysis (iHD) and continuous renal replacement therapy (CRRT) remains unclear. This study aimed to investigate and compare the impact of iHD and CRRT on coagulation and platelet function.

METHODS

Critically ill patients undergoing RRT were classified into the iHD group or the CRRT group. After the first blood sampling, patients underwent either a single session of hemodialysis or 48 h of CRRT, then a second blood sample was taken. Rotational thromboelastometry (ROTEM), platelet aggregometry and conventional coagulation tests were performed. The primary outcome was a change in extrinsically activated ROTEM (EXTEM) clotting time (CT).

RESULTS

60 dialysis sessions from 56 patients were finally included, with 30 dialysis sessions per group. EXTEM CT was prolonged significantly after dialysis in the iHD group (90 [74, 128] vs. 74 [61, 91], p < 0.001), but did not change in the CRRT group (94.4 ± 29.4 vs. 91.6 ± 22.9, p = 0.986). The platelet aggregation did not change after both iHD and CRRT. A change in EXTEM CT was significantly greater in the iHD group compared to the CRRT group (p = 0.006). The difference in the incidence of bleeding events was insignificant between the two groups (p = 0.301).

CONCLUSIONS

EXTEM CT was significantly prolonged after iHD, but this change was not shown after CRRT. Platelet function was not affected by both dialysis modalities.

Fluid balance neutralization secured by hemodynamic monitoring versus protocolized standard of care in patients with acute circulatory failure requiring continuous renal replacement therapy: results of the GO NEUTRAL randomized controlled trial

PURPOSE

Net ultrafiltration (UFNET) during continuous renal replacement therapy (CRRT) can control fluid balance (FB), but is usually 0 ml·h-1 in patients with vasopressors due to the risk of hemodynamic instability associated with CRRT (HIRRT). We evaluated a UFNET strategy adjusted by functional hemodynamics to control the FB of patients with vasopressors, compared to the standard of care.

METHODS

In this randomized, controlled, open-label, parallel-group, multicenter, proof-of-concept trial, adults receiving vasopressors, CRRT since ≤ 24 h and cardiac output monitoring were randomized (ratio 1:1) to receive during 72 h a UFNET ≥ 100 ml·h-1, adjusted using a functional hemodynamic protocol (intervention), or a UFNET ≤ 25 ml·h-1 (control). The primary outcome was the cumulative FB at 72 h and was analyzed in patients alive at 72 h and in whom monitoring and CRRT were continuously provided (modified intention-to-treat population [mITT]). Secondary outcomes were analyzed in the intention-to-treat (ITT) population.

RESULTS

Between June 2021 and April 2023, 55 patients (age 69 [interquartile range, IQR: 62; 74], 35% female, Sequential Organ Failure Assessment (SOFA) 13 [11; 15]) were randomized (25 interventions, 30 controls). In the mITT population, (21 interventions, 24 controls), the 72 h FB was -2650 [-4574; -309] ml in the intervention arm, and 1841 [821; 5327] ml in controls (difference: 4942 [95% confidence interval: 2736-6902] ml, P < 0.01). Hemodynamics, oxygenation and the number of HIRRT at 72 h, and day-90 mortality did not statistically differ between arms.

CONCLUSION

In patients with vasopressors, a UFNET fluid removal strategy secured by a hemodynamic protocol allowed active fluid balance control, compared to the standard of care.

Predictors of intradialytic hypotension in critically ill patients undergoing kidney replacement therapy: a systematic review

BACKGROUND

This systematic review aims to identify predictors of intradialytic hypotension (IDH) in critically ill patients undergoing kidney replacement therapy (KRT) for acute kidney injury (AKI).

METHODS

A comprehensive search of PubMed was conducted from 2002 to April 2024. Studies included critically ill adults undergoing KRT for AKI, excluding pediatric patients, non-critically ill individuals, those with chronic kidney disease, and those not undergoing KRT. The primary outcome was identifying predictive tools for hypotensive episodes during KRT sessions.

RESULTS

The review analyzed data from 8 studies involving 2873 patients. Various machine learning models were assessed for their predictive accuracy. The Extreme Gradient Boosting Machine (XGB) model was the top performer with an area under the receiver operating characteristic curve (AUROC) of 0.828 (95% CI 0.796-0.861), closely followed by the deep neural network (DNN) with an AUROC of 0.822 (95% CI 0.789-0.856). All machine learning models outperformed other predictors. The SOCRATE score, which includes cardiovascular SOFA score, index capillary refill, and lactate level, had an AUROC of 0.79 (95% CI 0.69-0.89, p < 0.0001). Peripheral perfusion index (PPI) and heart rate variability (HRV) showed AUROCs of 0.721 (95% CI 0.547-0.857) and 0.761 (95% CI 0.59-0.887), respectively. Pulmonary vascular permeability index (PVPI) and mechanical ventilation also demonstrated significant diagnostic performance. A PVPI ≥ 1.6 at the onset of intermittent hemodialysis (IHD) sessions predicted IDH associated with preload dependence with a sensitivity of 91% (95% CI 59-100%) and specificity of 53% (95% CI 42-63%).

CONCLUSION

This systematic review shows how combining predictive models with clinical indicators can forecast IDH in critically ill AKI patients undergoing KRT, with validation in diverse settings needed to improve accuracy and patient care strategies.

Factors Affecting Continuous Renal Replacement Therapy (CRRT) in Patients With Septic Shock: An Analysis of a National Inpatient Sample Database

BACKGROUND

Septic shock is defined as sepsis with hypotension requiring vasopressors to maintain a mean arterial pressure above 65 mmHg and having a serum lactate level of more than 2 mmol/L despite adequate volume resuscitation as per the Sepsis-3 criteria. Continuous renal replacement therapy (CRRT) is commonly utilized in septic shock patients for the treatment of acute kidney injury as well as for modulating immune response and maintaining hemodynamic stability.

METHODS

We looked at the National Inpatient Sample database in 2019. We identified adult patients with septic shock as the primary diagnosis using the International Classification of Diseases, 10th revision, clinical modification codes R65.21 and R78.81, and subbranches of Aa41, A40, and R60. STATA 18 (StataCorp, College Station, TX) was used to perform logistic multivariate regression analyses.

RESULTS

A total of 15,794 adults who were admitted for septic shock as the primary diagnosis underwent CRRT. The mean age of the patients was 61.7 years. The overall mortality rate was 57% (N = 9,002). An increase in age by one year was associated with a 1% increase in mortality (p = 0.001). The presence of hypertension increased mortality by 29% (N = 6,391) (p = 0.028). Interestingly, preexisting diabetes mellitus improved mortality by 37% (N = 3331) (p = 0.001).The outcome of CRRT was better in patients with chronic kidney disease, with a 26% improvement in mortality (N = 2341) (p = 0.001). A significant improvement in outcome (29% decrease in mortality, p=0.013) and 31% reduction in hospital length of stay (p = 0.008) was noted with CRRT initiated on day 2 of hospitalization.

CONCLUSION

This study highlights that the approximate time of initiation of CRRT for optimal benefit of the treatment is between 24 and 48 hours of hospitalization. This study emphasizes the prognostic factors of a standard therapy, which can serve as a basis for clinical decision-making.

Prevalence of cardiovascular instability during hemodialysis therapy in hospitalized patients: A systematic review and meta-analysis

BACKGROUND

Intradialytic hypotension (IDH) is a common and serious complication in renal replacement therapy, especially in hospitalized patients. The absence of a standardized definition complicates data synthesis and the development of evidence-based guidelines. Current definitions vary, including different blood pressure thresholds, clinical symptoms, and the need for medical intervention during dialysis. IDH is linked to increased mortality and cardiovascular morbidity and may impede renal recovery in patients with acute kidney injury and chronic kidney disease.

METHODS

A systematic review was conducted using MEDLINE via PubMed, Embase, and Web of Science to identify studies reporting IDH prevalence. A meta-analysis of proportions was performed to determine the global prevalence of IDH, with subgroup analyses to explore heterogeneity. The Joanna Briggs Institute's checklist was used to assess the risk of bias in prevalence studies. The PRISMA guidelines were followed to report the results of this study, PROSPERO registration number CRD42024500622.

RESULTS

The meta-analysis found a global IDH prevalence of 31% (95% CI 0.18-0.44) across nine studies. Significant heterogeneity was observed (I²: 97.87%; p < 0.01), with prevalence rates ranging from 10.7% to 64% based on patient demographics and session characteristics. Sensitivity analysis suggested prevalence could range between 27% and 33% depending on study criteria.

CONCLUSIONS

IDH is a significant complication during hospital-based renal replacement therapy, with a global prevalence of 31%. These findings highlight the need for a standardized, evidence-based definition of IDH to improve diagnostic consistency and clinical outcomes through more accurate diagnosis, better treatment strategies, and tailored patient management.

Predicting intradialytic hypotension in critically ill patients undergoing intermittent hemodialysis: a prospective observational study

BACKGROUND

Hypotension during dialysis arises from vasomotor tone alterations and hypovolemia, with disrupted counterregulatory mechanisms in acute kidney injury (AKI) patients. This study investigated the predictive value of preload dependency, assessed by the passive leg raising (PLR) test, and arterial tone, measured by dynamic elastance (Eadyn), for intradialytic hypotension (IDH).

METHODS

In this prospective observational study conducted in a tertiary hospital ICU, hemodynamic parameters were collected from critically ill AKI patients undergoing intermittent hemodialysis using the FloTrac/Vigileo system. Baseline measurements were recorded before KRT initiation, including the PLR test and Eadyn calculation. IDH was defined as mean arterial pressure (MAP) < 65 mmHg during dialysis. Logistic regression was used to identify predictors of IDH, and Kaplan-Meier analysis assessed 90-day survival.

RESULTS

Of 187 patients, 27.3% experienced IDH. Preload dependency, identified by positive PLR test, was significantly associated with IDH (OR 8.54, 95% CI 5.25-27.74), while baseline Eadyn was not predictive of IDH in this cohort. Other significant predictors of IDH included norepinephrine use (OR 16.35, 95% CI 3.87-68.98) and lower baseline MAP (OR 0.96, 95% CI 0.94-1.00). IDH and a positive PLR test were associated with lower 90-day survival (p < 0.001).

CONCLUSIONS

The PLR test is a valuable tool for predicting IDH in critically ill AKI patients undergoing KRT, while baseline Eadyn did not demonstrate predictive value in this setting. Continuous hemodynamic monitoring, including assessment of preload dependency, may optimize patient management and potentially improve outcomes. Further research is warranted to validate these findings and develop targeted interventions to prevent IDH.

Effect of Change in Sodium after Slow Low-Efficiency Dialysis in Critically Ill Patients with Acute Kidney Injury

INTRODUCTION

The effect of sodium (Na) correction by slow low-efficiency dialysis (SLED) in dysnatremic (135 mEq/L 145 mEq/L) critically ill patients is unclear.

METHODS

Prospective observational study enrolled dysnatremic critically ill adult patients with acute kidney injury undergoing the first SLED as cases and normonatremic patients as controls. Baseline and SLED-related parameters and 30-day mortality were noted.

RESULTS

100 dysnatremic and 51 normonatremic patients were included, with a median age of 31 (25-52) years and median admission SOFA scores of 10 (9-12). Patients with dysnatremia at study inclusion had a mortality of 53%, with the highest mortality in severe hypernatremia (Na >160 mEq/L) (75%), followed by those with severe hyponatremia (Na <120 mEq/L) (68.6%). SLED-associated natremia change >10 mEq/L was significantly associated with mortality, in patients with mild dysnatremia and normonatremia (Na: 130-150) (p < 0.001), and not in those with moderate to severe dysnatremia (Na <130 and Na >150) (p = 0.72). Upon multivariate logistic regression analysis, a model with pre-SLED pH, dialyzate-pre-SLED Na difference, and duration of SLED significantly predicted SLED-associated natremia change (R2 0.18, p = 0.001).

CONCLUSIONS

SLED can be safely and effectively performed in critically ill adults with dysnatremia requiring renal replacement therapy with mortality comparable to normonatremic controls.

Incidence and associated factors for hypotension during continuous renal replacement therapy in critically ill patients

AIMS

This work aimed to analyse retrospective data on hypotension incidence and associated factors among patients requiring continuous renal replacement therapy.

BACKGROUND

The incidence and risk factors of continuous renal replacement therapy-related hypotension have not been adequately explored.

DESIGN

The study was designed as a retrospective analysis.

METHODS

Patients who required continuous renal replacement therapy in the ICU between January 2017 and June 2021 were reviewed. The multivariate logistic regression model was used to determine the associated factors of hypotension.

RESULTS

Hypotension occurred in 242 out of 885 circuits (27.3%) among 140 patients. The logistic regression analysis identified seven factors associated with the occurrence of hypotension during CRRT: serum albumin (OR = 0.969, 95%CI: 0.934-0.999), serum calcium (OR = 0.514, 95%CI: 0.345-0.905), CO2CP (OR = 0.933, 95%CI: 0.897-0.971), use of vasopressors (OR = 5.731, 95%CI: 4.023-8.165), hypotension before CRRT initiation (OR = 2.779, 95%CI:1.238-6.242), age (OR = 1.016, 95%CI: 1.005-1.027), and fluid removal rate (OR = 1.002, 95%CI: 1.001-1.003).

CONCLUSIONS

Hypotension frequently occurs in patients receiving continuous renal replacement therapy, especially in the early stages. Multiple factors can be associated with cardiac output or peripheral resistance changes, including excessive ultrafiltration, vasopressors, serum albumin and serum calcium levels, and carbon dioxide combining power.

Hospital-acquired bacterial pneumonia in critically ill patients: from research to clinical practice

INTRODUCTION

Hospital-acquired pneumonia (HAP) represents a significant cause of mortality among critically ill patients admitted to Intensive Care Units (ICUs). Timely and precise diagnosis is imperative to enhance therapeutic efficacy and patient outcomes. However, the diagnostic process is challenged by test limitations and a wide-ranging list of differential diagnoses, particularly in patients exhibiting escalating oxygen requirements, leukocytosis, and increased secretions.

AREAS COVERED

This narrative review aims to update diagnostic modalities, facilitating the prompt identification of nosocomial pneumonia while guiding, developing, and assessing therapeutic interventions. A comprehensive literature review was conducted utilizing the MEDLINE/PubMed database from 2013 to April 2024.

EXPERT OPINION

An integrated approach that integrates clinical, microbiological, and imaging tools is paramount. Progress in diagnostic techniques, including novel molecular methods, the expanding utilization and accuracy of bedside ultrasound, and the emergence of Artificial Intelligence, coupled with an improved comprehension of lung microbiota and host-pathogen interactions, continues to enhance our capability to accurately and swiftly identify HAP and its causative agents. This advancement enables the refinement of treatment strategies and facilitates the implementation of precision medicine approaches.

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).

Prolonged capillary refill time and short-term mortality of critically ill patients: A meta-analysis

BACKGROUND

Prolonged capillary refill time (CRT) is an indicator of poor peripheral perfusion. The aim of the systematic review and meta-analysis was to evaluate the association of prolonged CRT and mortality of critically ill patients.

METHODS

To achieve the objective of this meta-analysis, we conducted a thorough search of PubMed, Embase, Cochrane Library, and the Web of Science to identify relevant observational studies with longitudinal follow-up. The Cochrane Q test was utilized to assess between-study heterogeneity, and the I2 statistic was calculated to estimate the degree of heterogeneity. We employed random-effects models to combine the outcomes, considering the potential influence of heterogeneity.

RESULTS

Eleven studies, encompassing 11,659 critically ill patients were included. During follow-up durations within hospitalization to 3 months, 1247 (10.7%) patients died. The pooled results indicated that a prolonged CRT at early phase of admission was significantly associated with an increased risk of all-cause mortality (risk ratio [RR]: 1.73, 95% confidence interval [CI]: 1.39 to 2.16, p < 0.001; I2 = 60%). Subgroup analyses showed that the association was not significantly modified by study design (prospective or retrospective), etiology of diseases (infection, non-infection, or mixed), or cutoff of CRT (>3 s, 3.5 s, or 4 s). The association between CRT and mortality was weaker in studies with multivariate analysis (RR: 1.43, 95% CI: 1.27 to 1.60, p < 0.001; I2 = 0%) as compared to that derived from studies of univariate analysis (RR: 6.27, 95% CI: 3.29 to 11.97, p < 0.001; I2 = 0%).

CONCLUSIONS

Prolonged CRT at admission may be a predictor of increased short-term mortality of critically ill patients.

Knowledge, attitude, practice, needs, and implementation status of intensive care unit staff toward continuous renal replacement therapy: a survey of 66 hospitals in central and South China

BACKGROUND

Continuous renal replacement therapy (CRRT) is a commonly utilized form of renal replacement therapy (RRT) in the intensive care unit (ICU). A specialized CRRT team (SCT, composed of physicians and nurses) engage playing pivotal roles in administering CRRT, but there is paucity of evidence-based research on joint training and management strategies. This study armed to evaluate the knowledge, attitude, and practice (KAP) of ICU staff toward CRRT, and to identify education pathways, needs, and the current status of CRRT implementation.

METHODS

This study was performed from February 6 to March 20, 2023. A self-made structured questionnaire was used for data collection. Descriptive statistics, T-tests, Analysis of variance (ANOVA), multiple linear regression, and Pearson correlation coefficient tests (α = 0.05) were employed.

RESULTS

A total of 405 ICU staff from 66 hospitals in Central and South China participated in this study, yielding 395 valid questionnaires. The mean knowledge score was 51.46 ± 5.96 (61.8% scored highly). The mean attitude score was 58.71 ± 2.19 (73.9% scored highly). The mean practice score was 18.15 ± 0.98 (85.1% scored highly). Multiple linear regression analysis indicated that gender, age, years of CRRT practice, ICU category, and CRRT specialist panel membership independently affected the knowledge score; Educational level, years of CRRT practice, and CRRT specialist panel membership independently affected the attitude score; Education level and teaching hospital employment independently affected the practice score. The most effective method for ICU staff to undergo training and daily work experience is within the department.

CONCLUSION

ICU staff exhibit good knowledge, a positive attitude and appropriately practiced CRRT. Extended CRRT practice time in CRRT, further training in a general ICU or teaching hospital, joining a CRRT specialist panel, and upgraded education can improve CRRT professional level. Considering the convenience of training programs will enhance ICU staff participation. Training should focus on basic CRRT principles, liquid management, and alarm handling.

Impact of Using Blood Warmer During Continuous Kidney Replacement Therapy in Patients With Acute Kidney Injury

PURPOSE

We investigated the impact of blood warmer use on hypotensive episodes in patients with acute kidney injury (AKI) receiving continuous kidney replacement therapy (CKRT).

MATERIALS AND METHODS

We included patients with AKI undergoing CKRT between January 1, 2012, and January 1, 2021, at a tertiary academic hospital. Hypotensive episodes were defined as mean arterial pressure (MAP) <60 mm Hg or a decrease in MAP by ≥10 mm Hg, systolic blood pressure (SBP) < 90 mm Hg or a decrease in SBP by ≥20 mm Hg, or increased vasopressor requirement. These were analyzed by Poisson regression with repeated-measures analysis of variance using generalized estimation equation.

RESULTS

There were 669 patients with AKI that required CKRT. Use of blood warmer on first day of CKRT was in 324 (48%) patients. Incidence rate ratio of hypotensive episodes during the first 24-h of CKRT in patients where a blood warmer was used was 1.06 (95% confidence interval [CI]: 0.98-1.13) compared to those where blood warmer was not used. This did not change in adjusted model. Overall, the within-subject effect of temperature on hypotensive episodes showed that higher temperature was associated with fewer episodes (0.94, 95% CI: 0.9-0.99 per 10 degrees increase, P = .007).

CONCLUSION

Blood rewarming was not associated with hypotensive episodes during CKRT.

Risk of Subdural Hematoma Expansion in Patients With End-Stage Renal Disease: Continuous Venovenous Hemodialysis Versus Intermittent Hemodialysis

BACKGROUND AND OBJECTIVES

Subdural hematoma (SDH) patients with end-stage renal disease (ESRD) require renal replacement therapy in addition to neurological management. We sought to determine whether continuous venovenous hemodialysis (CVVHD) or intermittent hemodialysis (iHD) is associated with higher rates of SDH re-expansion as well as morbidity and mortality.

METHODS

Hemodialysis-dependent patients with ESRD who were discovered to have an SDH were retrospectively identified from 2016 to 2022. Rates of SDH expansion during CVVHD vs iHD were compared. Hemodialysis mode was included in a multivariate logistic regression model to test for independent association with SDH expansion and mortality.

RESULTS

A total of 123 hemodialysis-dependent patients with ESRD were discovered to have a concomitant SDH during the period of study. Patients who received CVVHD were on average 10.2 years younger ( P < .001), more likely to have traumatic SDH (47.7% vs 19.0%, P < .001), and more likely to have cirrhosis (25.0% vs 10.1%, P = .029). SDH expansion affecting neurological function occurred more frequently during iHD compared with CVVHD (29.7% vs 12.0%, P = .013). Multivariate logistic regression analysis found that CVVHD was independently associated with decreased risk of SDH affecting neurological function (odds ratio 0.25, 95% CI 0.08-0.65). Among patients who experienced in-hospital mortality or were discharged to hospice, 5% suffered a neurologically devastating SDH expansion while on CVVHD compared with 35% on iHD.

CONCLUSION

CVVHD was independently associated with decreased risk of neurologically significant SDH expansion. Therefore, receiving renal replacement therapy through a course of CVVHD may increase SDH stability in patients with ESRD.

Impact of the first 24 h of continuous kidney replacement therapy on hemodynamics, ventilation, and analgo-sedation in critically ill children

BACKGROUND

In a group of children admitted to the paediatric intensive care unit (PICU) receiving continuous kidney replacement therapy (CKRT), we aim to evaluate the data about their hemodynamic, ventilation and analgo-sedation profile in the first 24 h of treatment and possible associations with mortality.

METHODS

Retrospective cohort study of children admitted to the PICU of the University Hospital of Padova undergoing CKRT between January 2011 and March 2021. Data was collected at baseline (T0), after 1 h (T1) and 24 h (T24) of CKRT treatment. The differences in outcome measures were compared between these time points, and between survivors and non-survivors.

RESULTS

Sixty-nine patients received CKRT, of whom 38 (55%) died during the PICU stay. Overall, the vasoactive inotropic score and the adrenaline dose increased at T1 compared to T0 (p = 0.012 and p = 0.022, respectively). Compared to T0, at T24 patients showed an improvement in the following ventilatory parameters: Oxygenation Index (p = 0.005), Oxygenation Saturation Index (p = 0.013) PaO2/FiO2 ratio (p = 0.005), SpO2/FiO2 ratio (p = 0.002) and Mean Airway Pressure (p = 0.016). These improvements remained significant in survivors (p = 0.01, p = 0.027, p = 0.01 and p = 0.015, respectively) but not in non-survivors. No changes in analgo-sedative drugs have been described.

CONCLUSIONS

CKRT showed a significant impact on hemodynamics and ventilation in the first 24 h of treatment. We observed a significant rise in the inotropic/vasoactive support required after 1 h of treatment in the overall population, and an improvement in the ventilation parameters at 24 h only in survivors.

Fluid Balance in Continuous Renal Replacement Therapy: Prescribing, Delivering, and Review

BACKGROUND

Historically IV and enteral fluids given during acute kidney injury (AKI) were restricted before the introduction of continuous renal replacement therapies (CRRTs) when more liberal fluids improved nutrition for the critically ill. However, fluid accumulation can occur when higher volumes each day are not considered in the fluid balance prescribing and the NET ultrafiltration (NUF) volume target.

KEY MESSAGES

The delivered hours of CRRT each day are vital for achievement of fluid balance and time off therapy makes the task more challenging. Clinicians inexperienced with CRRT make this aspect of AKI management a focus of rounding with senior oversight, clear communication, and "precision" a clinical target. Sepsis-associated AKI can be a complex patient where resuscitation and admission days are with a positive fluid load and replacement mind set. Subsequent days in ICU requires fluid regulation, removal, with a comprehensive multilayered assessment before prescribing the daily fluid balance target and the required hourly NET plasma water removal rate (NUF rate). Future machines may include advanced software, new alarms - display metrics, messages and association with machine learning and "AKI models" for setting, monitoring, and guaranteeing fluid removal. This could also link to current hardware such as on-line blood volume assessment with continuous haematocrit measurement.

SUMMARY

Fluid balance in the acutely ill is a challenge where forecasting and prediction are necessary. NUF rate and volume each hour should be tracked and adjusted to achieve the daily target. This requires human and machine connections.

Global Scientific Trends in Continuous Renal Replacement Therapy from 2000 to 2023: A Bibliometric and Visual Analysis

INTRODUCTION

Continuous renal replacement therapy (CRRT) is one of the most widely used blood purification and organ support methods in the ICU. However, the development process, the current status, hotspots, and future trends of CRRT remain unclear.

METHOD

The WoSCC database was used to analyze CRRT research evolution and theme trends. VOSviewer was used to construct coauthorship, co-occurrence, co-citation, and network visualizations. CiteSpace is used to detect bursts for co-occurrence items. Several important subtopics were reviewed and discussed in more detail.

RESULTS

Global publications increased from 56 in 2000 to 398 in 2023, a 710.71% increase. Blood Purification published the most manuscripts, followed by the International Journal of Artificial Organs. The USA, the San Bortolo Hospital, and Bellomo were the most productive and impactful institution, country, and author, respectively. Based on co-occurrence cluster analysis, five clusters emerged: (1) clinical applications and management of CRRT; (2) sepsis and CRRT; (3) CRRT anticoagulant management; (4) CRRT and antibiotic pharmacokinetics and pharmacodynamics; and (5) comparison of CRRT and intermittent hemodialysis. COVID-19, initiation, ECOMO, cefepime, guidelines, cardiogenic shock, biomarker, and outcome were the latest high-frequency keywords or strongest bursts, indicating the emerging frontiers of CRRT.

CONCLUSIONS

There has been widespread publication and citation of CRRT research in the past 2 decades. We provide an overview of current trends, global collaboration patterns, basic knowledge, research hotspots, and emerging frontiers.

Early Net Ultrafiltration during Continuous Renal Replacement Therapy: Impact of Admission Diagnosis and Association with Mortality

INTRODUCTION

Continuous renal replacement therapy (CRRT) is common in the intensive care unit (ICU) but a high net ultrafiltration rate (UFNET) calculated with daily data may increase mortality. We aimed to study early UFNET practice using minute-by-minute CRRT machine recordings and to assess its association with admission diagnosis and mortality.

METHODS

We studied CRRT treatments in three adult ICUs over 7 years. We calculated early UFNET rates minute-by-minute and categorized UFNET into tertiles of mean UFNET in the first 72 h and admission diagnosis. We applied Cox-proportional hazards modelling with censoring of patients who died within 72 h.

RESULTS

We studied 1,218 patients, 154,712 h, and 9,282,729 min of CRRT (5,702 circuits). Mean early UFNET was 1.52 (1.46-1.57) mL/kg/h. Early UFNET tertiles were similar to, but somewhat higher than, previously reported values at 0.00-1.20 mL/kg/h, 1.21-1.93 mL/kg/h, and >1.93 mL/kg/h. UFNET values were similar whether evaluated at 24 or 72 h or for the entire duration of CRRT. There was, however, significant variation in UFNET practice by admission diagnosis: higher in respiratory diseases (pneumonia p = 0.01, other p < 0.0001) and cardiovascular disease (p = 0.005) but lower in cardiothoracic surgery (p = 0.04), renal (p = 0.0003) and toxicology-associated diagnoses (p = 0.01). Higher UFNET was associated with an increased hazard of death, HR 1.24 (1.13-1.37), independent of admission diagnosis, weight, age, sex, presence of end-stage kidney disease, and severity of illness.

CONCLUSION

Early UFNET practice varies significantly by admission diagnosis. Higher early UFNET is independently associated with mortality. Impacts of UFNET on mortality may vary by admission diagnosis. Further work is required to elucidate the nature and mechanisms responsible for this association.

Practical considerations for individualizing drug dosing in critically ill adults receiving renal replacement therapy

Critically ill patients with sepsis admitted to the intensive care unit (ICU) often present with or develop renal dysfunction requiring renal replacement therapy (RRT) in addition to antimicrobial therapy. While early and appropriate antimicrobials for sepsis have been associated with an increased probability of survival, adequate dosing is also required in these patients. Adequate dosing of antimicrobials refers to dosing strategies that achieve serum drug levels at the site of infection that are able to provide a microbiological and/or clinical response while avoiding toxicity from excessive antibiotic exposure. Therapeutic drug monitoring (TDM) is the recommended strategy to achieve this goal, however, TDM is not routinely available in all ICUs and for all antimicrobials. In the absence of TDM, clinicians are therefore required to make dosing decisions based on the clinical condition of the patient, the causative organism, the characteristics of RRT, and an understanding of the physicochemical properties of the antimicrobial. Pharmacokinetics (PK) of antimicrobials can be highly variable between critically ill patients and also within the same patient over the course of their ICU stay. The initiation of RRT, which can be in the form of intermittent hemodialysis, continuous, or prolonged intermittent therapy, further complicates the predictability of drug disposition. This variability highlights the need for individualized dosing. This review highlights the practical considerations for the clinician for antimicrobial dosing in critically ill patients receiving RRT.

Optimal management of cardiac surgery patients using direct oral anticoagulants: recommendations for clinical practice

OBJECTIVES

Literature is scarce on the management of patients using direct oral anticoagulants (DOACs) undergoing elective, urgent and emergency surgery. Therefore, we summarize the current evidence and provide literature-based recommendations for the management of patients on DOACs in the perioperative phase.

METHODS

A general literature review was conducted on the pharmacology of DOACs and for recommendations on the management of cardiac surgical patients on DOACs. Additionally, we performed a systematic review for studies on the use of direct DOAC reversal agents in the emergency cardiac surgical setting.

RESULTS

When surgery is elective, the DOAC cessation strategy is relatively straightforward and should be adapted to the renal function. The same approach applies to urgent cases, but additional DOAC activity drug level monitoring tests may be useful. In emergency cases, idarucizumab can be safely administered to patients on dabigatran in any of the perioperative phases. However, andexanet alfa, which is not registered for perioperative use, should not be administered in the preoperative phase to reverse the effect of factor Xa inhibitors, as it may induce temporary heparin resistance. Finally, the administration of (activated) prothrombin complex concentrate may be considered in all patients on DOACs, and such concentrates are generally readily available.

CONCLUSIONS

DOACs offer several advantages over vitamin K antagonists, but care must be taken in patients undergoing cardiac surgery. Although elective and urgent cases can be managed relatively straightforwardly, the management of emergency cases requires particular attention.

BENEFIT OF HIGHER BLOOD PRESSURE TARGET IN SEVERE ACUTE KIDNEY INJURY TREATED BY CONTINUOUS RENAL REPLACEMENT THERAPY

ABSTRACT

Introduction : The optimal target of mean arterial pressure (MAP) during continuous renal replacement therapy (CRRT) is unknown. Method : We retrospectively collected the hourly MAP data in acute kidney injury patients requiring CRRT who admitted to the intensive care unit in the University of Tokyo hospital during 2011-2019. Patients who died within 48 h of CRRT start and whose average value of hourly MAPs during the first 48 h was <65 mm Hg were excluded. When the average value of MAP was ≤75 mm Hg or >75 mm Hg, patients were allocated to the low or high target group. We estimated the effect of MAP on mortality and RRT independence at 90 days, using multivariable the Cox regression model and Fine and Gray model. Result : Of the 275 patients we analyzed, 95 patients were in the low group. There are no differences in sex, baseline kidney function, and disease severity. At 90 days, the low target group had higher mortality with 38 deaths (40.0%) compared with 57 deaths (31.7%) in the high target group ( P < 0.05). The adjusted hazard ratio of the low target group (≤75 mm Hg) for mortality was 1.72 (95% CI, 1.08-2.74). In addition, the low target group had a lower rate of RRT independence, with 60 patients (63.2%) compared with 136 patients (75.6%) in the high target group ( P < 0.05). The multivariable analysis revealed that the adjusted hazard ratio of the low target group for RRT independence was 0.74 (95% CI, 0.54-1.01). Conclusion : This study found the association with low MAP and mortality. The association with low MAP and delayed renal recovery was not revealed.

Syndecan-1 predicts hemodynamic instability in critically ill patients under intermittent hemodialysis

Introduction

Up to 70% of intermittent hemodialysis (IHD) sessions in critically ill patients are complicated by hemodynamic instability. Although several clinical characteristics have been associated with hemodynamic instability during IHD, the discriminatory capacity of predicting such events during IHD sessions is less defined. In the present study, we aimed to analyse endothelium-related biomarkers collected before IHD sessions and their capacity to predict hemodynamic instability related to IHD in critically ill patients.

Methods

In this prospective observational study, we enrolled adult critically ill patients with acute kidney injury who required fluid removal with IHD. We screened each included patient daily for IHD sessions. Thirty minutes before each IHD session, each patient had a 5-mL blood collection for measurement of endothelial biomarkers-vascular cell adhesion molecule-1 (VCAM-1), angiopoietin-1 and -2 (AGPT1 and AGPT2) and syndecan-1. Hemodynamic instability during IHD was the main outcome. Analyses were adjusted for variables already known to be associated with hemodynamic instability during IHD.

Results

Plasma syndecan-1 was the only endothelium-related biomarker independently associated with hemodynamic instability. The accuracy of syndecan-1 for predicting hemodynamic instability during IHD was moderate [area under the receiver operating characteristic curve 0.78 (95% confidence interval 0.68-0.89)]. The addition of syndecan-1 improved the discrimination capacity of a clinical model from 0.67 to 0.82 (P < .001) and improved risk prediction, as measured by net reclassification improvement.

Conclusion

Syndecan-1 is associated with hemodynamic instability during IHD in critically ill patients. It may be useful to identify patients who are at increased risk for such events and suggests that endothelial glycocalyx derangement is involved in the pathophysiology of IHD-related hemodynamic instability.

Volume Management with Kidney Replacement Therapy in the Critically Ill Patient

While the administration of intravenous fluids remains an important treatment, the negative consequences of subsequent fluid overload have raised questions about when and how clinicians should pursue avenues of fluid removal. Decisions regarding fluid removal during critical illness are complex even for patients with preserved kidney function. This article seeks to apply general concepts of fluid management to the care of patients who also require KRT. Because optimal fluid management for any specific patient is likely to change over the course of critical illness, conceptual models using phases of care have been developed. In this review, we will examine the implications of one such model on the use of ultrafiltration during KRT for volume removal in distributive shock. This will also provide a useful lens to re-examine published data of KRT during critical illness. We will highlight recent prospective trials of KRT as well as recent retrospective studies examining ultrafiltration rate and mortality, review the results, and discuss applications and shortcomings of these studies. We also emphasize that current data and techniques suggest that optimal guidelines will not consist of recommendations for or against absolute fluid removal rates but will instead require the development of dynamic protocols involving frequent cycles of reassessment and adjustment of net fluid removal goals. If optimal fluid management is dynamic, then frequent assessment of fluid responsiveness, fluid toxicity, and tolerance of fluid removal will be needed. Innovations in our ability to assess these parameters may improve our management of ultrafiltration in the future.

Debate: Intermittent Hemodialysis versus Continuous Kidney Replacement Therapy in the Critically Ill Patient: The Argument for CKRT

Continuous kidney replacement therapy (CKRT) is well entrenched as one of the dominant KRT modalities in modern critical care practice. Since its introduction four decades ago, there have been considerable innovations in CKRT machines that have improved precision, safety, and simplicity. CKRT is the preferred KRT modality for critically ill patients with hemodynamic instability. Early physical therapy and rehabilitation can be feasibly and safely provided to patients connected to CKRT, thus obviating concerns about immobility. Although randomized clinical trials have not shown a mortality difference when comparing CKRT and intermittent hemodialysis, CKRT allows precision delivery of solute and fluid removal that can be readily adjusted in the face of dynamic circumstances. Accumulated evidence from observational studies, although susceptible to bias, has shown that CKRT, when compared with intermittent hemodialysis, is associated with better short- and long-term kidney recovery and KRT independence. Critical care medicine encompasses a wide range of sick patients, and no single KRT modality is likely to ideally suit every patient in every context and for every condition. The provision of KRT represents a spectrum of modalities to which patients can flexibly transition in response to their evolving condition. As a vital tool for organ support in the intensive care unit, CKRT enables the personalization of KRT to meet the clinical demands of patients during the most severe phases of their illness.

Debate: Intermittent Hemodialysis versus Continuous Kidney Replacement Therapy in the Critically Ill Patient: The Choice Should Be Evidence Based

Kidney replacement therapy (KRT) plays a major role in the treatment of severe AKI. Intermittent hemodialysis (HD) and continuous KRT (CKRT) are the main modalities in critically ill patients with AKI. CKRT is the preferred modality in many countries because of its alleged superiority on both hemodynamic tolerance and on kidney function recovery. In fact, randomized controlled trials (RCTs) comparing the two modalities have not shown any actual benefit of one technique over the other on mortality, hemodynamics, or kidney function recovery. Those RCTs were conducted more than 15 years ago. Major progress was eventually made leading to much lower mortality rates in recent studies than in previous studies. In addition, those RCTs included a noticeable proportion of patients who could have recovered without ever receiving KRT, as demonstrated by several recent studies. In the absence of evidence of clinical superiority of one KRT modality, the choice must be addressed not only regarding clinical outcome but also resources and logistics. Conclusions of health technology assessments and study reports were heterogeneous and conflicting concerning cost-effectiveness of intermittent HD versus CKRT. All these considerations justify a reevaluation of the issue in new RCTs that take into account recent knowledge on KRT initiation and management. Pending results of such study, the choice should be guided mainly by organizational considerations in each unit and without condemning any modality in the absence of proof.

An update review on hemodynamic instability in renal replacement therapy patients

BACKGROUND

Hemodynamic instability in patients undergoing kidney replacement therapy (KRT) is one of the most common and essential factors influencing mortality, morbidity, and the quality of life in this patient population.

METHOD

Decreased cardiac preload, reduced systemic vascular resistance, redistribution of fluids, fluid overload, inflammatory factors, and changes in plasma osmolality have all been implicated in the pathophysiology of hemodynamic instability associated with KRT.

RESULT

A cascade of these detrimental mechanisms may ultimately cause intra-dialytic hypotension, reduced tissue perfusion, and impaired kidney rehabilitation. Multiple parameters, including dialysate composition, temperature, posture during dialysis sessions, physical activity, fluid administrations, dialysis timing, and specific pharmacologic agents, have been studied as possible management modalities. Nevertheless, a clear consensus is not reached.

CONCLUSION

This review includes a thorough investigation of the literature on hemodynamic instability in KRT patients, providing insight on interventions that may potentially minimize factors leading to hemodynamic instability.

How I prescribe prolonged intermittent renal replacement therapy

Prolonged Intermittent Renal Replacement Therapy (PIRRT) is the term used to define 'hybrid' forms of renal replacement therapy. PIRRT can be provided using an intermittent hemodialysis machine or a continuous renal replacement therapy (CRRT) machine. Treatments are provided for a longer duration than typical intermittent hemodialysis treatments (6-12 h vs. 3-4 h, respectively) but not 24 h per day as is done for continuous renal replacement therapy (CRRT). Usually, PIRRT treatments are provided 4 to 7 times per week. PIRRT is a cost-effective and flexible modality with which to safely provide RRT for critically ill patients. We present a brief review on the use of PIRRT in the ICU with a focus on how we prescribe it in that setting.

How I prescribe prolonged intermittent renal replacement therapy

Prolonged Intermittent Renal Replacement Therapy (PIRRT) is the term used to define 'hybrid' forms of renal replacement therapy. PIRRT can be provided using an intermittent hemodialysis machine or a continuous renal replacement therapy (CRRT) machine. Treatments are provided for a longer duration than typical intermittent hemodialysis treatments (6-12 h vs. 3-4 h, respectively) but not 24 h per day as is done for continuous renal replacement therapy (CRRT). Usually, PIRRT treatments are provided 4 to 7 times per week. PIRRT is a cost-effective and flexible modality with which to safely provide RRT for critically ill patients. We present a brief review on the use of PIRRT in the ICU with a focus on how we prescribe it in that setting.

Sustained Low Efficiency Dialysis in Critically Ill Children With Acute Kidney Injury: Single-Center Observational Cohort in a Resource-Limited Setting

OBJECTIVES

To evaluate use of sustained low efficiency dialysis (SLED) in critically ill children with acute kidney injury in a resource-limited setting.

DESIGN

Observational database cohort study (December 2016 to January 2020).

SETTING

PICU of a tertiary hospital in India.

PATIENTS

Critically ill children undergoing SLED were included in the study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic and clinical data, prescription variables, hemodynamic status, complications, kidney, and patient outcomes of all children undergoing SLED in the PICU were analyzed. A total of 33 children received 103 sessions of SLED. The median (interquartile range, IQR) age and weight of children who received SLED were 9 years (4.5-12.8 yr) and 26 kg (15.2-34 kg), respectively. The most common diagnosis was sepsis with septic shock in 17 patients, and the mean (± sd ) Pediatric Risk of Mortality III score at admission was 11.8 (±6.4). The median (IQR) number and mean (± sd ) duration of inotropes per session were 3 hours (2-4 hr) and 96 (±82) hours, respectively. Of 103 sessions, the most common indication for SLED was oligoanuria with fluid overload and the need for creating space for fluid and nutritional support in 45 sessions (44%). The mean (± sd ) duration of SLED was 6.4 (±1.3) hours with 72 of 103 sessions requiring priming. The mean (± sd ) ultrafiltration rate per session achieved was 4.6 (±3) mL/kg/hr. There was significant decrease in urea and creatinine by end of SLED compared with the start, with mean change in urea and serum creatinine being 32.36 mg/dL (95% CI, 18.53-46.18 mg/dL) ( p < 0.001) and 0.70 mg/dL (95% CI, 0.35-1.06 mg/dL) ( p < 0.001), respectively. Complications were observed in 44 of 103 sessions, most common being intradialytic hypotension (21/103) and bleeding at the catheter site (21/103). Despite complications in one third of the sessions, only nine sessions were prematurely stopped, and 23 of 33 patients receiving SLED survived.

CONCLUSION

In critically ill children, our experience with SLED is that it is feasible and provides a viable form of kidney replacement therapy in a resource-limited setting.

Impact of intradialytic hypotension on mortality following the transition from continuous renal replacement therapy to intermittent hemodialysis

BACKGROUND

The transition of dialysis modalities from continuous renal replacement therapy (CRRT) to intermittent hemodialysis (iHD) is frequently conducted during the recovery phase of critically ill patients with acute kidney injury. Herein, we addressed the occurrence of intradialytic hypotension (IDH) after this transition, and its association with the mortality risk.

METHODS

A total of 541 patients with acute kidney injury who attempted to transition from CRRT to iHD at Seoul National University Hospital, Korea from 2010 to 2020 were retrospectively collected. IDH was defined as a discontinuation of dialysis because of hemodynamic instability plus a nadir systolic blood pressure <90 mm Hg or a decrease in systolic blood pressure ≥30 mm Hg during the first session of iHD. Odds ratios (ORs) of outcomes, such as in-hospital mortality and weaning from RRT, were measured using a logistic regression model after adjusting for multiple variables.

RESULTS

IDH occurred in 197 patients (36%), and their mortality rate (44%) was higher than that of those without IDH (19%; OR, 2.64; 95% confidence interval [CI], 1.70-4.08). For patients exhibiting IDH, the iHD sessions delayed successful weaning from RRT (OR, 0.62; 95% CI, 0.43-0.90) compared with sessions on those without IDH. Factors such as low blood pressure, high pulse rate, low urine output, use of mechanical ventilations and vasopressors, and hypoalbuminemia were associated with IDH risk.

CONCLUSIONS

IDH occurrence following the transition from CRRT to iHD is associated with high mortality and delayed weaning from RRT.

Management of Intermittent Hemodialysis in the Critically Ill Patient

Intermittent hemodialysis remains a cornerstone of extracorporeal KRT in the intensive care unit, either as a first-line therapy for AKI or a second-line therapy when patients transition from a continuous or prolonged intermittent therapy. Intermittent hemodialysis is usually provided 3 days per week in this setting on the basis that no clinical benefits have been demonstrated with more frequent hemodialysis. This should not detract from the importance of continually assessing and refining the hemodialysis prescription (including the need for extra treatments) according to dynamic changes in extracellular volume and other parameters, and ensuring that an adequate dose of hemodialysis is being delivered to the patient. Compared with other KRT modalities, the cardinal challenge encountered during intermittent hemodialysis is hemodynamic instability. This phenomenon occurs when reductions in intravascular volume, as a consequence of ultrafiltration and/or osmotic shifts, outpace compensatory plasma refilling from the extravascular space. Myocardial stunning, triggered by intermittent hemodialysis, and independent of ultrafiltration, may also contribute. The hemodynamic effect of intermittent hemodialysis is likely magnified in patients who are critically ill due to an inability to mount sufficient compensatory physiologic responses in the context of multiorgan dysfunction. Of the many interventions that have undergone testing to mitigate hemodynamic instability related to KRT, the best evidence exists for cooling the dialysate and raising the dialysate sodium concentration. Unfortunately, the evidence supporting routine use of these and other interventions is weak owing to poor study quality and limited sample sizes. Intermittent hemodialysis will continue to be an important and commonly used KRT modality for AKI in patients with critical illness, especially in jurisdictions where resources are limited. There is an urgent need to harmonize the definition of hemodynamic instability related to KRT in clinical trials and robustly test strategies to combat it in this vulnerable patient population.

Continuous KRT: A Contemporary Review

AKI is a common complication of critical illness and is associated with substantial morbidity and risk of death. Continuous KRT comprises a spectrum of dialysis modalities preferably used to provide kidney support to patients with AKI who are hemodynamically unstable and critically ill. The various continuous KRT modalities are distinguished by different mechanisms of solute transport and use of dialysate and/or replacement solutions. Considerable variation exists in the application of continuous KRT due to a lack of standardization in how the treatments are prescribed, delivered, and optimized to improve patient outcomes. In this manuscript, we present an overview of the therapy, recent clinical trials, and outcome studies. We review the indications for continuous KRT and the technical aspects of the treatment, including continuous KRT modality, vascular access, dosing of continuous KRT, anticoagulation, volume management, nutrition, and continuous KRT complications. Finally, we highlight the need for close collaboration of a multidisciplinary team and development of quality assurance programs for the provision of high-quality and effective continuous KRT.

Refilling and preload dependence failed to predict cardiac index decrease during fluid removal with continuous renal replacement therapy

BACKGROUND

Fluid removal can reduce the burden of fluid overload after initial resuscitation. According to the Frank-Starling model, iatrogenic hypovolemia should induce a decrease in cardiac index. We hypothesized that inadequate refilling detected by haemoconcentration during fluid removal or an increase in cardiac index (CI) during passive leg raising (PLR) could predict CI decrease during mechanical fluid removal with continuous renal replacement therapy (CRRT).

METHODS

We conducted a single-centre prospective diagnostic accuracy study. The primary objective was to investigate the diagnostic performance of plasma protein concentration variations in detecting a CI decrease ≥ 12% during mechanical fluid removal. Secondary objective was to assess other predictive factors of CI change. The attending physician prescribed a fluid removal challenge consisting of a mechanical fluid removal challenge of 500 mL for one hour. Plasma protein concentration, haemoglobin level, PLR and transpulmonary thermodilution were done before and after the fluid removal challenge.

RESULTS

We included 69 adult patients between December 2016 and April 2020. Sixteen patients had a significant CI decrease (23% [95% CI 14-35]). Haemoconcentration and PLR before fluid removal challenge or CI trending failed to predict CI decrease.

CONCLUSION

Haemoconcentration variables, preload dependence status and CI trending failed to predict CI decrease during fluid removal challenge.

Regional Citrate Anticoagulation or Heparin Anticoagulation for Renal Replacement Therapy in Patients With Liver Failure: A Systematic Review and Meta-Analysis

In patients with liver failure complicated by acute kidney injury, renal replacement therapy (RRT) is often required to improve the internal environment. The use of anticoagulants for RRT in patients with liver failure remains controversial. We searched the PubMed, Embase, Cochrane Library, and Web of Science databases for studies. The methodological quality of the included studies was assessed using the Methodological Index for Nonrandomized Studies. A meta-analysis was performed using R software (version 3.5.1) and Review Manager (version 5.3.5). During RRT, 348 patients from 9 studies received regional citrate anticoagulation (RCA), and 127 patients from 5 studies received heparin anticoagulation (including heparin and LMWH). Among patients who received RCA, the incidence of citrate accumulation, metabolic acidosis, and metabolic alkalosis were 5.3% (95% confidence interval [CI]: 0%-25.3%), 26.4% (95% CI: 0-76.9), and 1.8% (95% CI: 0-6.8), respectively. The potassium, phosphorus, total bilirubin (TBIL), and creatinine levels were lower, whereas the serum pH, bicarbonate, base excess levels, and total calcium/ionized calcium ratio were higher after treatment than before treatment. Among patients who received heparin anticoagulation, the TBIL levels were lower, whereas the activated partial thromboplastin clotting time and D-dimer levels were higher after treatment than before treatment. The mortality rates in the RCA and heparin anticoagulation groups were 58.9% (95% CI: 39.2-77.3) and 47.4% (95% CI: 31.1-63.7), respectively. No statistical difference in mortality was observed between the 2 groups. For patients with liver failure, the administration of RCA or heparin for anticoagulation during RRT under strict monitoring may be safe and effective.

Perfusion-based deresuscitation during continuous renal replacement therapy: A before-after pilot study (The early dry Cohort)

BACKGROUND

Active fluid removal has been suggested to improve prognosis following the resolution of acute circulatory failure. We have implemented a routine care protocol to guide fluid removal during continuous renal replacement therapy (CRRT). We designed a before-after pilot study to evaluate the impact of this deresuscitation strategy on the fluid balance.

METHODS

Consecutive ICU patients suffering from fluid overload and undergoing CRRT for acute kidney injury underwent a perfusion-based deresuscitation protocol combining a restrictive intake, net ultrafiltration (UFnet) of 2 mL/kg/h, and monitoring of perfusion (early dry group, N = 42) and were compared to a historical group managed according to usual practices (control group, N = 45). The primary outcome was the cumulative fluid balance at day 5 or at discharge.

RESULTS

Adjusted cumulative fluid balance was significantly lower in the early dry group (median [IQR]: -7784 [-11,833 to -2933] mL) compared to the control group (-3492 [-9935 to -1736] mL; p = 0.04). The difference was mainly driven by a greater daily UFnet (31 [22-46] mL/kg/day vs. 24 [15-32] mL/kg/day; p = 0.01). There was no significant difference between both groups regarding hemodynamic tolerance.

CONCLUSION

Our perfusion-based deresuscitation protocol achieved a greater negative cumulative fluid balance compared to standard practices and was hemodynamically well tolerated.

Complications Associated With Venovenous Extracorporeal Membrane Oxygenation-What Can Go Wrong?

OBJECTIVES

Despite increasing use and promising outcomes, venovenous extracorporeal membrane oxygenation (V-V ECMO) introduces the risk of a number of complications across the spectrum of ECMO care. This narrative review describes the variety of short- and long-term complications that can occur during treatment with ECMO and how patient selection and management decisions may influence the risk of these complications.

DATA SOURCES

English language articles were identified in PubMed using phrases related to V-V ECMO, acute respiratory distress syndrome, severe respiratory failure, and complications.

STUDY SELECTION

Original research, review articles, commentaries, and published guidelines from the Extracorporeal Life support Organization were considered.

DATA EXTRACTION

Data from relevant literature were identified, reviewed, and integrated into a concise narrative review.

DATA SYNTHESIS

Selecting patients for V-V ECMO exposes the patient to a number of complications. Adequate knowledge of these risks is needed to weigh them against the anticipated benefit of treatment. Timing of ECMO initiation and transfer to centers capable of providing ECMO affect patient outcomes. Choosing a configuration that insufficiently addresses the patient's physiologic deficit leads to consequences of inadequate physiologic support. Suboptimal mechanical ventilator management during ECMO may lead to worsening lung injury, delayed lung recovery, or ventilator-associated pneumonia. Premature decannulation from ECMO as lungs recover can lead to clinical worsening, and delayed decannulation can prolong exposure to complications unnecessarily. Short-term complications include bleeding, thrombosis, and hemolysis, renal and neurologic injury, concomitant infections, and technical and mechanical problems. Long-term complications reflect the physical, functional, and neurologic sequelae of critical illness. ECMO can introduce ethical and emotional challenges, particularly when bridging strategies fail.

CONCLUSIONS

V-V ECMO is associated with a number of complications. ECMO selection, timing of initiation, and management decisions impact the presence and severity of these potential harms.

Characteristics of and Outcomes After Dialysis-Treated Acute Kidney Injury, 2009-2018: A Taiwanese Multicenter Study

RATIONALE & OBJECTIVE

Dialysis-treated acute kidney injury (AKI) is increasingly common in intensive care units (ICUs) and is associated with poor outcomes. Few studies have explored the temporal trends in severity of acute illness at dialysis initiation, indications for dialysis, and their association with patient outcomes.

STUDY DESIGN

Multicenter retrospective cohort study.

SETTING & PARTICIPANTS

9,535 adult patients admitted to the ICU who received their first dialysis treatment from Chang Gung Memorial Hospital system in Taiwan from 2009 through 2018.

EXPOSURE

Calendar year.

OUTCOMES

ICU mortality and dialysis treatment at discharge among hospital survivors.

ANALYTICAL APPROACH

The temporal trends during the study period were investigated using test statistics suited for continuous or categorical data. The association between the study year and the risk of mortality was analyzed using multivariable Cox regression with adjustment for relevant clinical variables, including the severity of acute illness, defined by Sequential Organ Failure Assessment (SOFA) score.

RESULTS

The mean SOFA score at dialysis initiation decreased slightly from 14.0 in 2009 to 13.6 in 2018. There was no significant trend in the number of indications for dialysis initiation that were fulfilled over time. Observed ICU mortality decreased over time, and the curve appeared to be reverse J-shaped, with a substantial decrease from 56.1% in 2009 to 46.3% in 2015 and a slight increase afterward. The risk of mortality was significantly reduced from 2013 to 2018 compared with 2009 in adjusted models. The decreasing trend in ICU mortality over time remained significant. There was an increase in dialysis treatment at discharge among survivors, mainly in patients with estimated glomerular filtration rate<60mL/min/1.73m², from 36.8% in 2009 to 43.9% in 2018.

LIMITATIONS

Residual confounding from unmeasured factors over time such as severity of comorbidities, detailed medication interventions, and delivered dialysis dose.

CONCLUSIONS

We observed reductions in mortality among ICU patients with dialysis-treated acute kidney injury between 2009 and 2018, even after adjusting for dialysis indication and severity of illness at dialysis initiation. However, dialysis treatment at discharge among survivors has increased over time, mainly in patients with preexisting kidney disease.

Continuous extracorporeal clearance in metformin-associated lactic acidosis and metformin-induced lactic acidosis: a systematic review

INTRODUCTION

Metformin poisoning with lactic acidosis is an uncommon yet clinically serious condition related to the inhibition of normal aerobic metabolism. Toxicity may occur after an acute overdose although it is much more common after a systemic insult, such as acute kidney injury, in the setting of chronic use. Hemodialysis is currently the preferred extracorporeal treatment modality (Grade 1D evidence) although some patients may be too hemodynamically unstable to tolerate it. Continuous renal replacement therapy is considered an alternative if hemodialysis is unavailable but an evaluation of survival amongst this specific treatment class is lacking.

OBJECTIVES

To assess overall survival and provide an updated review of the toxicokinetic elimination parameters of patients receiving continuous renal replacement therapy for metformin poisoning.

METHODS

A comprehensive search was performed using the EMBASE and MEDLINE libraries from inception until November 30, 2021. Data was extracted and findings were summarized. Toxicokinetic parameters were analyzed and confirmed for accuracy when data permitted.

RESULTS

Eighty-three reports met inclusion criteria. These consisted of only low-quality evidence including 75 case reports, four case series, and four descriptive retrospective reviews. Overall survival among patients suffering from metformin toxicity who received continuous extracorporeal treatment was 85.8%. When stratified between metformin-induced lactic acidosis and metformin-associated lactic acidosis, survival was 75.0% and 87.4%, respectively. Available continuous renal replacement therapy toxicokinetic parameters were quite heterogeneous. Errors in previously published toxicokinetic calculations were noted in only two instances. The overall average and median peak metformin concentrations were 70.5 mg/L and 41.9 mg/L, respectively. The average and median extracorporeal clearance rates were 39.0 mL/min and 42.1 mL/min (range 9.0-58.7 mL/min). The average and median elimination half-life parameters were 27.5 h and median 23.0 h. Elimination half-life ranged from seven to 74 h. There was no meaningful relationship between peak metformin concentration and continuous extracorporeal treatment half-life at lower concentrations, though at very high concentrations (over 200 mg/L), there was a trend towards a half-life below 20 h. There is insufficient data to robustly evaluate overall survival in relation to the extracorporeal clearance rate. Finally, there was no relevant relationship between maximal lactate concentration and survival, nor nadir pH and survival, for patients with either type of metformin toxicity.

CONCLUSIONS

This retrospective systematic analysis of published cases treating metformin related lactic acidosis with continuous renal replacement therapy notes an overall slightly greater survival percentage compared to previous publications of individuals requiring any modality of renal replacement therapy. Because of publication bias, these results should be interpreted with caution and serve as hypothesis generating for future research. Prospective study focusing on the most clinically meaningful endpoint - survival - will help elucidate if continuous modalities are non-inferior to intermittent hemodialysis in metformin toxicity.