Unsupervised machine learning analysis to identify patterns of ICU medication use for fluid overload prediction

INTRODUCTION

Intravenous (IV) medications are a fundamental cause of fluid overload (FO) in the intensive care unit (ICU); however, the association between IV medication use (including volume), administration timing, and FO occurrence remains unclear.

METHODS

This retrospective cohort study included consecutive adults admitted to an ICU ≥72 hours with available fluid balance data. FO was defined as a positive fluid balance ≥7% of admission body weight within 72 hours of ICU admission. After reviewing medication administration record (MAR) data in three-hour periods, IV medication exposure was categorized into clusters using principal component analysis (PCA) and Restricted Boltzmann Machine (RBM). Medication regimens of patients with and without FO were compared within clusters to assess for temporal clusters associated with FO using the Wilcoxon rank sum test. Exploratory analyses of the medication cluster most associated with FO for medications frequently appearing and used in the first 24 hours was conducted.

RESULTS

FO occurred in 127/927 (13.7%) of the patients enrolled. Patients received a median (IQR) of 31 (13-65) discrete IV medication administrations over the 72-hour period. Across all 47,803 IV medication administrations, ten unique IV medication clusters were identified with 121-130 medications in each cluster. Among the ten clusters, cluster 7 had the greatest association with FO; the mean number of cluster 7 medications received was significantly greater in patients in the FO cohort compared to patients who did not experience FO (25.6 vs.10.9. p<0.0001). 51 of the 127 medications in cluster 7 (40.2%) appeared in > 5 separate 3-hour periods during the 72-hour study window. The most common cluster 7 medications included continuous infusions, antibiotics, and sedatives/analgesics. Addition of cluster 7 medications to a prediction model with APACHE II score and receipt of diuretics improved the ability for the model to predict fluid overload (AUROC 5.65, p =0.0004).

CONCLUSIONS

Using ML approaches, a unique IV medication cluster was strongly associated with FO. Incorporation of this cluster improved the ability to predict development of fluid overload in ICU patients compared with traditional prediction models. This method may be further developed into real-time clinical applications to improve early detection of adverse outcomes.

Machine learning vs. traditional regression analysis for fluid overload prediction in the ICU

Fluid overload, while common in the ICU and associated with serious sequelae, is hard to predict and may be influenced by ICU medication use. Machine learning (ML) approaches may offer advantages over traditional regression techniques to predict it. We compared the ability of traditional regression techniques and different ML-based modeling approaches to identify clinically meaningful fluid overload predictors. This was a retrospective, observational cohort study of adult patients admitted to an ICU ≥ 72 h between 10/1/2015 and 10/31/2020 with available fluid balance data. Models to predict fluid overload (a positive fluid balance ≥ 10% of the admission body weight) in the 48-72 h after ICU admission were created. Potential patient and medication fluid overload predictor variables (n = 28) were collected at either baseline or 24 h after ICU admission. The optimal traditional logistic regression model was created using backward selection. Supervised, classification-based ML models were trained and optimized, including a meta-modeling approach. Area under the receiver operating characteristic (AUROC), positive predictive value (PPV), and negative predictive value (NPV) were compared between the traditional and ML fluid prediction models. A total of 49 of the 391 (12.5%) patients developed fluid overload. Among the ML models, the XGBoost model had the highest performance (AUROC 0.78, PPV 0.27, NPV 0.94) for fluid overload prediction. The XGBoost model performed similarly to the final traditional logistic regression model (AUROC 0.70; PPV 0.20, NPV 0.94). Feature importance analysis revealed severity of illness scores and medication-related data were the most important predictors of fluid overload. In the context of our study, ML and traditional models appear to perform similarly to predict fluid overload in the ICU. Baseline severity of illness and ICU medication regimen complexity are important predictors of fluid overload.

Adult Cardiac Surgery-Associated Acute Kidney Injury: Joint Consensus Report

OBJECTIVES

Acute kidney injury (AKI) is increasingly recognized as a source of poor patient outcomes after cardiac surgery. The purpose of the present report is to provide perioperative teams with expert recommendations specific to cardiac surgery-associated AKI (CSA-AKI).

METHODS

This report and consensus recommendations were developed during a joint, in-person, multidisciplinary conference with the Perioperative Quality Initiative and the Enhanced Recovery After Surgery Cardiac Society. Multinational practitioners with diverse expertise in all aspects of cardiac surgical perioperative care, including clinical backgrounds in anesthesiology, surgery and nursing, met from October 20 to 22, 2021, in Sacramento, California, and used a modified Delphi process and a comprehensive review of evidence to formulate recommendations. The quality of evidence and strength of each recommendation were established using the Grading of Recommendations Assessment, Development, and Evaluation methodology. A majority vote endorsed recommendations.

RESULTS

Based on available evidence and group consensus, a total of 13 recommendations were formulated (4 for the preoperative phase, 4 for the intraoperative phase, and 5 for the postoperative phase), and are reported here.

CONCLUSIONS

Because there are no reliable or effective treatment options for CSA-AKI, evidence-based practices that highlight prevention and early detection are paramount. Cardiac surgery-associated AKI incidence may be mitigated and postsurgical outcomes improved by focusing additional attention on presurgical kidney health status; implementing a specific cardiopulmonary bypass bundle; using strategies to maintain intravascular euvolemia; leveraging advanced tools such as the electronic medical record, point-of-care ultrasound, and biomarker testing; and using patient-specific, goal-directed therapy to prioritize oxygen delivery and end-organ perfusion over static physiologic metrics.

Renal medicine in the intensive care unit: a narrative review

Kidney disease, both acute and chronic, is commonly encountered on the intensive care unit. Due to the role the kidneys play in whole body homeostasis, it follows that their dysfunction has wide-ranging implications and can affect prescribing and therapeutic management. This narrative review discusses the pathophysiology of acute kidney injury and chronic kidney disease, and how this relates to critically unwell patients. We cover several aspects of the management of renal dysfunction on the critical care unit, exploring some of the recurrent themes within the literature, including type and timing of kidney replacement therapy, management of acute kidney injury, as well as discussing how novel biomarkers for acute kidney injury may help to identify patients suffering from acute kidney injury as well as risk stratifying these patients. We discuss how early involvement of specialist nephrology services can improve outcomes in patients with kidney disease as well as offer valuable diagnostic and specialist management advice, particularly for patients with established end stage kidney disease and patients who are already known to nephrology services. We also explore some of the ongoing research questions that need to be answered within this arena.

A system theory based digital model for predicting the cumulative fluid balance course in intensive care patients

Background: Surgical interventions can cause severe fluid imbalances in patients undergoing cardiac surgery, affecting length of hospital stay and survival. Therefore, appropriate management of daily fluid goals is a key element of postoperative intensive care in these patients. Because fluid balance is influenced by a complex interplay of patient-, surgery- and intensive care unit (ICU)-specific factors, fluid prediction is difficult and often inaccurate. Methods: A novel system theory based digital model for cumulative fluid balance (CFB) prediction is presented using recorded patient fluid data as the sole parameter source by applying the concept of a transfer function. Using a retrospective dataset of n = 618 cardiac intensive care patients, patient-individual models were created and evaluated. RMSE analyses and error calculations were performed for reasonable combinations of model estimation periods and clinically relevant prediction horizons for CFB. Results: Our models have shown that a clinically relevant time horizon for CFB prediction with the combination of 48 h estimation time and 8-16 h prediction time achieves high accuracy. With an 8-h prediction time, nearly 50% of CFB predictions are within ±0.5 L, and 77% are still within the clinically acceptable range of ±1.0 L. Conclusion: Our study has provided a promising proof of principle and may form the basis for further efforts in the development of computational models for fluid prediction that do not require large datasets for training and validation, as is the case with machine learning or AI-based models. The adaptive transfer function approach allows estimation of CFB course on a dynamically changing patient fluid balance system by simulating the response to the current fluid management regime, providing a useful digital tool for clinicians in daily intensive care.

Perioperative Management of the Patient at High-Risk for Cardiac Surgery-Associated Acute Kidney Injury

Acute kidney injury (AKI) is one of the most common major complications of cardiac surgery, and is associated with increased morbidity and mortality. Cardiac surgery-associated AKI has a complex, multifactorial etiology, including numerous factors such as primary cardiac dysfunction, hemodynamic derangements of cardiac surgery and cardiopulmonary bypass, and the possibility of a large volume of blood transfusion. There are no truly effective pharmacologic therapies for the management of AKI, and, therefore, anesthesiologists, intensivists, and cardiac surgeons must remain vigilant and attempt to minimize the risk of developing renal dysfunction. This narrative review describes the current state of the scientific literature concerning the specific aspects of cardiac surgery-associated AKI, and presents it in a chronological fashion to aid the perioperative clinician in their approach to this high-risk patient group. The evidence was considered for risk prediction models, preoperative optimization, and the intraoperative and postoperative management of cardiac surgery patients to improve renal outcomes.

Fluid overload: clinical outcomes in pediatric intensive care unit

OBJECTIVE

The aim of this study was to analyze the effects of fluid overload related to mechanical ventilation, renal replacement therapy, and evolution to discharge or death in critically ill children.

METHODS

A retrospective study in a Pediatric Intensive Care Unit for two years. Patients who required invasive ventilatory support and vasopressor and/or inotropic medications were considered critically ill.

RESULTS

70 patients were included. The mean age was 6.8 ± 6 years. There was a tolerable increase in fluid overload during hospitalization, with a median of 2.45% on the first day, 5.10% on the third day, and 8.39% on the tenth day. The median fluid overload on the third day among those patients in pressure support ventilation mode was 4.80% while the median of those who remained on controlled ventilation was 8.45% (p = 0.039). Statistical significance was observed in the correlations between fluid overload measurements on the first, third, and tenth days of hospitalization and the beginning of renal replacement therapy (p = 0.049) and between renal replacement therapy and death (p = 0.01). The median fluid overload was 7.50% in patients who died versus 4.90% in those who did not die on the third day of hospitalization (p = 0.064). There was no statistically significant association between death and the variables sex or age.

CONCLUSIONS

The fluid overload on the third day of hospitalization proved to be a determinant for the clinical outcomes of weaning from mechanical ventilation, initiation of renal replacement therapy, discharge from the intensive care unit, or death among these children.

The Effect of Aminophylline on Urine Output and Fluid Balance after a Single Dose in Children Admitted to the Pediatric Cardiac Intensive Care Unit

The purpose of this retrospective study was to investigate the effects of a single dose of aminophylline on urine output and fluid balance in children admitted to the cardiac intensive care unit. A retrospective study was performed to compare variables of interest before and 24 hours after aminophylline administration in children under the age of 18 years who were admitted to the cardiac intensive care unit at our institution from January 2011 onwards. Variables of interest included age, weight, aminophylline dose, concurrently administered diuretics, specific hemodynamic parameters, and blood urea nitrogen and creatinine levels. Variables such as urine output and fluid balance were measured through a binary endpoint. Data were compared in a paired fashion and continuous variables were compared through paired t-tests. Analyses were conducted using SPSS Version 23.0. A total of 14 patients were included in the study. There was no significant change in hemodynamic parameters or creatinine levels before and after intravenous aminophylline administration of 5 mg/kg. There was a significant difference in urine output, fluid balance, and blood urea nitrogen levels from the baseline value. Concurrent usage of diuretics did not show significant association with a difference in urine output or fluid balance from baseline. No significant adverse reactions were noted 24 hours after administration of aminophylline. Use of aminophylline dosed at 5 mg/kg is safe and leads to improvement in urine output and fluid balance without negatively impacting systemic oxygen delivery or renal filtration function.

Fenoldopam Increases Urine Output in Oliguric Critically Ill Surgical Patients

Background Fenoldopam is a short-acting dopamine A1 receptor agonist which mediates vasodilation of the renal arteries, thereby increasing urine output. The objective of this study was to compare the effects of fenoldopam and its synergistic effect on furosemide for improving the urine output in postoperative critically ill patients with acute kidney injury (AKI). Methods This is a retrospective study of postoperative critically ill patients with AKI. Patients who received furosemide (control group) were compared with those who received furosemide plus fenoldopam (treatment group) and evaluated at 12 and 24 hours post-treatment. Patients with oliguria and AKI were included in the study, while patients with chronic kidney disease (CKD) were excluded. Glomerular filtration rate, serum creatinine, blood pressure, calculated fluid accumulation, fluid intake, urine output, and total fluid output were used as variables to assess the medication effect. Results Of the 126 patients who met the inclusion and exclusion criteria, 87 patients received furosemide alone, and 39 patients received furosemide plus fenoldopam during their first 24 hours of admission to the surgical intensive care unit (SICU). Although not statistically significant, the addition of fenoldopam demonstrated an increase in mean urine output of 1525ml (IQR; 1530-2095) in the first 24 hours (P=0.06). There was also noted an increase in the urine output (p= 0.07) and a decrease in the total fluid accumulation when fenoldopam was co-administered with furosemide when compared to the patients who were only treated with furosemide (p=0.06). There was no significant change in creatinine clearance from baseline in either group.  Conclusion Fenoldopam may increase urine output in postoperative critically ill patients with acute kidney injury when administered within the first 24 hours of presentation. Based on our results, fenoldopam appears to have a synergistic effect with furosemide in our study population.

Effect of half-molar sodium lactate infusion on biochemical parameters in critically ill patients

OBJECTIVE

To evaluate the impact of the infusion of sodium lactate 500ml upon different biochemical variables and intracranial pressure in patients admitted to the intensive care unit.

DESIGN

A prospective experimental single cohort study was carried out.

SCOPE

Polyvalent intensive care unit of a university hospital.

PATIENTS

Critical patients with shock and intracranial hypertension.

PROCEDURE

A 500ml sodium lactate bolus was infused in 15min. Plasma levels of sodium, potassium, magnesium, calcium, chloride, lactate, bicarbonate, PaCO₂, pH, phosphate and albumin were recorded at 3 timepoints: T0 pre-infusion; T1 at 30min, and T2 at 60min post-infusion. Mean arterial pressure and intracranial pressure were measured at T0 and T2.

RESULTS

Forty-one patients received sodium lactate: 19 as an osmotically active agent and 22 as a volume expander. Metabolic alkalosis was observed: T0 vs. T1 (p=0.007); T1 vs. T2 (p=0.003). Sodium increased at the 3 timepoints (T0 vs. T1, p<0.0001; T1 vs. T2, p=0.0001). In addition, sodium lactate decreased intracranial pressure (T0: 24.83±5.4 vs. T2: 15.06±5.8; p<0.001). Likewise, plasma lactate showed a biphasic effect, with a rapid decrease at T2 (p<0.0001), including in those with previous hyperlactatemia (p=0.002).

CONCLUSIONS

The infusion of sodium lactate is associated to metabolic alkalosis, hypernatremia, reduced chloremia, and a biphasic change in plasma lactate levels. Moreover, a decrease in intracranial pressure was observed in patients with acute brain injury.

Adjunct Use of Continuous Renal Replacement Therapy with Extracorporeal Membrane Oxygenation Achieves Negative Fluid Balance and Enhances Oxygenation Which Improves Survival in Critically Ill Patients without Kidney Failure

INTRODUCTION

Fluid overload in extracorporeal membrane oxygenation (ECMO) patients has been associated with increased mortality. Patients receiving ECMO and continuous renal replacement therapy (CRRT) who achieve a negative fluid balance have improved survival. Limited data exist on the use of CRRT solely for fluid management in ECMO patients.

METHODS

We performed a single-center retrospective review of 19 adult ECMO patients without significant renal dysfunction who received CRRT for fluid management. These patients were compared to a cohort of propensity-matched controls.

RESULTS

After 72 h, the treatment group had a fluid balance of -3840 mL versus + 425 mL (p ≤ 0.05). This lower fluid balance correlated with survival to discharge (odds ratio 2.54, 95% confidence interval 1.10-5.87). Improvement in the ratio of arterial oxygen content to fraction of inspired oxygen was also significantly higher in the CRRT group (102.4 vs. 0.7, p ≤ 0.05). We did not observe any significant difference in renal outcomes.

CONCLUSIONS

The use of CRRT for fluid management is effective and, when resulting in negative fluid balance, improves survival in adult ECMO patients without significant renal dysfunction.

Early Cumulative Fluid Balance and Outcomes in Pediatric Allogeneic Hematopoietic Cell Transplant Recipients With Acute Respiratory Failure: A Multicenter Study

OBJECTIVES

To evaluate the associations between early cumulative fluid balance (CFB) and outcomes among critically ill pediatric allogeneic hematopoietic cell transplant (HCT) recipients with acute respiratory failure, and determine if these associations vary by treatment with renal replacement therapy (RRT).

METHODS

We performed a secondary analysis of a multicenter retrospective cohort of patients (1mo - 21yrs) post-allogeneic HCT with acute respiratory failure treated with invasive mechanical ventilation (IMV) from 2009 to 2014. Fluid intake and output were measured daily for the first week of IMV (day 0 = day of intubation). The exposure, day 3 CFB (CFB from day 0 through day 3 of IMV), was calculated using the equation [Fluid in - Fluid out] (liters)/[PICU admission weight](kg)*100. We measured the association between day 3 CFB and PICU mortality with logistic regression, and the rate of extubation at 28 and 60 days with competing risk regression (PICU mortality = competing risk).

RESULTS

198 patients were included in the study. Mean % CFB for the cohort was positive on day 0 of IMV, and increased further on days 1-7 of IMV. For each 1% increase in day 3 CFB, the odds of PICU mortality were 3% higher (adjusted odds ratio (aOR) 1.03, 95% CI 1.00-1.07), and the rate of extubation was 3% lower at 28 days (adjusted subdistribution hazard ratio (aSHR) 0.97, 95% CI 0.95-0.98) and 3% lower at 60 days (aSHR 0.97, 95% CI 0.95-0.98). When day 3 CFB was dichotomized, 161 (81%) had positive and 37 (19%) had negative day 3 CFB. Positive day 3 CFB was associated with higher PICU mortality (aOR 3.42, 95% CI 1.48-7.87) and a lower rate of extubation at 28 days (aSHR 0.30, 95% CI 0.18-0.48) and 60 days (aSHR 0.30, 95% 0.19-0.48). On stratified analysis, the association between positive day 3 CFB and PICU mortality was significantly stronger in those not treated with RRT (no RRT: aOR 9.11, 95% CI 2.29-36.22; RRT: aOR 1.40, 95% CI 0.42-4.74).

CONCLUSIONS

Among critically ill pediatric allogeneic HCT recipients with acute respiratory failure, positive and increasing early CFB were independently associated with adverse outcomes.

Delaying initiation of diuretics in critically ill patients with recent vasopressor use and high positive fluid balance

BACKGROUND

Fluid overload is associated with poor outcomes. Clinicians might be reluctant to initiate diuretic therapy for patients with recent vasopressor use. We estimated the effect on 30-day mortality of withholding or delaying diuretics after vasopressor use in patients with probable fluid overload.

METHODS

This was a retrospective cohort study of adults admitted to ICUs of an academic medical centre between 2008 and 2012. Using a database of time-stamped patient records, we followed individuals from the time they first required vasopressor support and had >5 L cumulative positive fluid balance (plus additional inclusion/exclusion criteria). We compared mortality under usual care (the mix of care actually delivered in the cohort) and treatment strategies restricting diuretic initiation during and for various durations after vasopressor use. We adjusted for baseline and time-varying confounding via inverse probability weighting.

RESULTS

The study included 1501 patients, and the observed 30-day mortality rate was 11%. After adjusting for observed confounders, withholding diuretics for at least 24 h after stopping most recent vasopressor use was estimated to increase 30-day mortality rate by 2.2% (95% confidence interval [CI], 0.9-3.6%) compared with usual care. Data were consistent with moderate harm or slight benefit from withholding diuretic initiation only during concomitant vasopressor use; the estimated mortality rate increased by 0.5% (95% CI, -0.2% to 1.1%).

CONCLUSIONS

Withholding diuretic initiation after vasopressor use in patients with high cumulative positive balance (>5 L) was estimated to increase 30-day mortality. These findings are hypothesis generating and should be tested in a clinical trial.

The Association between Daily Fluid Balance and Mean Perfusion Pressure as a Critical Sign in the Intensive Care Unit of Adam Malik Central Hospital, Medan

BACKGROUND: The patient mortality rate in intensive care unit (ICU) is still high. However, we still lack measures to reduce this high mortality rate. Fluid balance is known as a marker for mortality in ICU. If the balance of fluid becomes more positive, the mortality rate consequently becomes higher. Positive fluid balance elevates central venous pressure (CVP), while this elevation increases the risk of renal failure and mortality. Mean perfusion pressure (MPP) is the difference between mean arterial pressure and CVP. AIM: We propose that the MPP value can be used as an alternative indicator to monitor excessive fluid balance since its measurement is faster and more accurate than the manual 24 h record of fluid balance. PATIENTS AND METHODS: It is expected that we can prevent excessive fluid accumulation and the subsequent mortality risk by monitoring MPP in the ICU. To investigate the association between MPP and daily fluid balance in the ICU, a prospective study was conducted from March 2016 to August 2018 in the ICU of Adam Malik Hospital, Medan. During the study period, 76 patients were admitted. Sixty-point 5% were male, with the mean age of 48.3 ± 16.5 years old. RESULTS: The overall mortality of 76 patients was 10.5%, and there was a significant negative correlation found between MPP and fluid balance (r = −0.204; p = 0.048), where a lower MPP value was associated with a more positive fluid balance. CONCLUSIONS: We conclude that there is a negative correlation between MPP and fluid balance, where a more positive fluid balance is associated with a lower MPP value. The positive fluid balance had been previously associated with increased mortality risk in the ICU.

Phases of fluid management and the roles of human albumin solution in perioperative and critically ill patients

OBJECTIVE

Positive fluid balance is common among critically ill patients and leads to worse outcomes, particularly in sepsis, acute respiratory distress syndrome, and acute kidney injury. Restrictive fluid infusion and active removal of accumulated fluid are being studied as approaches to prevent and treat fluid overload. Use of human albumin solutions has been investigated in different phases of restrictive fluid resuscitation, and this narrative literature review was undertaken to evaluate hypoalbuminemia and the roles of human serum albumin with respect to hypovolemia and its management.

METHODS

PubMed/EMBASE search terms were: "resuscitation," "fluids," "fluid therapy," "fluid balance," "plasma volume," "colloids," "crystalloids," "albumin," "hypoalbuminemia," "starch," "saline," "balanced salt solution," "gelatin," "goal-directed therapy" (English-language, pre-January 2020). Additional papers were identified by manual searching of reference lists.

RESULTS

Restrictive fluid administration, plus early vasopressor use, may reduce fluid balance, but in some cases fluid overload cannot be entirely avoided. Deresuscitation, with fluid actively removed through diuretics or ultrafiltration, reduces duration of mechanical ventilation and intensive care unit stay. Combining hyperoncotic human albumin solution with diuretics increases hemodynamic stability and diuresis. Hyperoncotic albumin corrects hypoalbuminemia and raises colloid osmotic pressure, limiting edema formation and potentially improving endothelial function. Serum levels of albumin relative to C-reactive protein and lactate may predict which patients will benefit most from albumin therapy.

CONCLUSIONS

Hyperoncotic human albumin solution facilitates restrictive fluid therapy and the effectiveness of deresuscitative measures. Current evidence is mostly from observational studies, and more randomized trials are needed to better establish a personalized approach to fluid management.

Review of acute kidney injury and continuous renal replacement therapy in pediatric extracorporeal membrane oxygenation

Purpose

To review the relevant literature of acute kidney injury (AKI) and continuous renal replacement therapy (CRRT) as it relates to pediatric extracorporeal membrane oxygenation (ECMO).

Methods

Available online relevant literature.

Results

ECMO is a therapeutic modality utilized to support patients with refractory respiratory and/or cardiac failure. AKI and fluid overload (FO) are frequently observed in this patient population. There are multiple modalities that can be utilized for AKI and FO which include the following: diuretics, in-line hemofiltration, and CRRT. There are multiple considerations when using CRRT with ECMO including access, CRRT flows, hemolysis, anticoagulation, and CRRT termination.

Conclusion

While each ECMO center has its own set of equipment, experiences, and practices, it is imperative that the international ECMO community continues to work together to provide an evidence-based approach to address the morbidity and mortality associated with AKI and FO.

A narrative review of pharmacologic de-resuscitation in the critically ill

Despite evidence highlighting harms of fluid overload, minimal guidance exists on counteraction via utilization of diuretics in the de-resuscitation phase. While diuretics have been shown to decrease net volume and improve clinical outcomes in the critically ill, a lack of standardization surrounding selection of diuretic regimen or monitoring of de-resuscitation exists. Current monitoring parameters of de-resuscitation often rely on clinical signs of fluid overload, end organ recovery and other biochemical surrogate markers which are often deemed unreliable. The majority of evidence suggests that achieving a net-negative fluid balance within 72 h after shock resolution may be of benefit; however, approaches to such goal are uncertain. Loop diuretics are a widely available type of diuretic for removal of volume in patients with sufficient kidney function, with the potential for adjunct diuretics in special circumstances. At present, administration of diuretics within the broad critically ill population fails to find uniformity and often efficacy. Given the lack of randomized controlled trials in this susceptible population, we aim to provide a thorough therapeutic understanding of diuretic pharmacotherapy which is necessary in order to achieve desired goal of fluid balance and improve overall outcomes.

Xanthine Derivatives for Kidney Protection in the Critically Ill Pediatric Population: A Systematic Review

Different types of diuretics have been used to minimize fluid overload after resuscitation. This meta-analysis determined the effects of xanthine derivatives on creatinine, creatinine clearance, and urine output. Studies included data from pediatric patients, whoused theophylline or aminophylline, and included pre- and postxanthine data for at least one of the outcomes of interest. A total of 13 studies with 198 patients were included in the pooled analyses. The study recorded data prior, and a mean of 36 hours after xanthine administration. This meta-analysis demonstrates that xanthine derivatives in critically ill children, using a dose of approximately5 mg/kg, lead to a statistically significant increase in creatinine clearance and urine output without significantly altering serum creatinine. Xanthine derivatives may be beneficial for fluid management in critically ill children. Further studies are warranted assessing the association with additional clinical outcomes.

Impact of protocolized diuresis for de-resuscitation in the intensive care unit

Objective

Administration of diuretics has been shown to assist fluid management and improve clinical outcomes in the critically ill post-shock resolution. Current guidelines have not yet included standardization or guidance for diuretic-based de-resuscitation in critically ill patients. This study aimed to evaluate the impact of a multi-disciplinary protocol for diuresis-guided de-resuscitation in the critically ill.

Methods

This was a pre-post single-center pilot study within the medical intensive care unit (ICU) of a large academic medical center. Adult patients admitted to the Medical ICU receiving mechanical ventilation with either (1) clinical signs of volume overload via chest radiography or physical exam or (2) any cumulative fluid balance ≥ 0 mL since hospital admission were eligible for inclusion. Patients received diuresis per clinician discretion for a 2-year period (historical control) followed by a diuresis protocol for 1 year (intervention). Patients within the intervention group were matched in a 1:3 ratio with those from the historical cohort who met the study inclusion and exclusion criteria.

Results

A total of 364 patients were included, 91 in the protocol group and 273 receiving standard care. Protocolized diuresis was associated with a significant decrease in 72-h post-shock cumulative fluid balance [median, IQR − 2257 (− 5676–920) mL vs 265 (− 2283–3025) mL; p < 0.0001]. In-hospital mortality in the intervention group was lower compared to the historical group (5.5% vs 16.1%; p = 0.008) and higher ICU-free days (p = 0.03). However, no statistically significant difference was found in ventilator-free days, and increased rates of hypernatremia and hypokalemia were demonstrated.

Conclusions

This study showed that a protocol for diuresis for de-resuscitation can significantly improve 72-h post-shock fluid balance with potential benefit on clinical outcomes.

Effect of half-molar sodium lactate infusion on biochemical parameters in critically ill patients

OBJECTIVE

To evaluate the impact of the infusion of sodium lactate 500ml upon different biochemical variables and intracranial pressure in patients admitted to the intensive care unit.

DESIGN

A prospective experimental single cohort study was carried out.

SCOPE

Polyvalent intensive care unit of a university hospital.

PATIENTS

Critical patients with shock and intracranial hypertension.

PROCEDURE

A 500ml sodium lactate bolus was infused in 15min. Plasma levels of sodium, potassium, magnesium, calcium, chloride, lactate, bicarbonate, PaCO₂, pH, phosphate and albumin were recorded at 3timepoints: T0 pre-infusion; T1 at 30minutes, and T2 at 60minutes post-infusion. Mean arterial pressure and intracranial pressure were measured at T0 and T2.

RESULTS

Forty-one patients received sodium lactate: 19 as an osmotically active agent and 22 as a volume expander. Metabolic alkalosis was observed: T0 vs. T1 (P=0.007); T1 vs. T2 (P=0.003). Sodium increased at the 3time points (T0 vs. T1, P<0.0001; T1 vs. T2, P=0.0001). In addition, sodium lactate decreased intracranial pressure (T0: 24.83±5.4 vs. T2: 15.06±5.8; P<0.001). Likewise, plasma lactate showed a biphasic effect, with a rapid decrease at T2 (P<0.0001), including in those with previous hyperlactatemia (P=0.002).

CONCLUSIONS

The infusion of sodium lactate is associated to metabolic alkalosis, hypernatremia, reduced chloremia, and a biphasic change in plasma lactate levels. Moreover, a decrease in intracranial pressure was observed in patients with acute brain injury.

Fluid Overload in Critically Ill Children

Background: A common practice in the management of critically ill patients is fluid resuscitation. An excessive administration of fluids can lead to an imbalance in fluid homeostasis and cause fluid overload (FO). In pediatric critical care patients, FO can lead to a multitude of adverse effects and increased risk of morbidity. Objectives: To review the literature highlighting impact of FO on a multitude of outcomes in critically-ill children, causative vs. associative relationship of FO with critical illness and current pediatric fluid management guidelines. Data Sources: A literature search was conducted using PubMed/Medline and Embase databases from the earliest available date until June 2017. Data Extraction: Two authors independently reviewed the titles and abstracts of all articles which were assessed for inclusion. The manuscripts of studies deemed relevant to the objectives of this review were then retrieved and associated reference lists hand-searched. Data Synthesis: Articles were segregated into various categories namely pathophysiology and sequelae of fluid overload, assessment techniques, epidemiology and fluid management. Each author reviewed the selected articles in categories assigned to them. All authors participated in the final review process. Conclusions: Recent evidence has purported a relationship between mortality and FO, which can be validated by prospective RCTs (randomized controlled trials). The current literature demonstrates that "clinically significant" degree of FO could be below 10%. The lack of a standardized method to assess FB (fluid balance) and a universal definition of FO are issues that need to be addressed. To date, the impact of early goal directed therapy and utility of hemodynamic parameters in predicting fluid responsiveness remains underexplored in pediatric resuscitation.

Adherence to Daily Weights and Total Fluid Orders in the Pediatric Intensive Care Unit

Supplemental Digital Content is available in the text.

Background:

Fluid is central to the resuscitation of critically ill children. However, many pay limited attention to continued fluid accumulation. Fluid overload (FO) is associated with significant morbidity and mortality. The Volume Status Awareness Program (VSAP) is a multi-phase quality improvement initiative aimed at reducing iatrogenic FO. For baseline data, the authors examined a retrospective cohort of patients admitted to the pediatric intensive care unit.

Methods:

Cohort included diuretic-naive patients admitted to the pediatric intensive care unit at a tertiary care children’s hospital in 2014. Furosemide-exposure was used to indicate provider-perceived FO. Variables included daily weight and total fluid (TF) orders, and their timing, frequency, and adherence. Implementation of VSAP phase 1 (bundle of interventions to promote consistent use of patient weights) occurred in June 2017.

Results:

Forty-nine patients met criteria. Five (10%) had daily weight orders, and 41 (84%) had TF orders—although 7 of these orders followed furosemide administration. Adherence to TF orders was good with 32 (78%) patients exceeding TF limits by < 10%. Thirty (63%) had > 5% FO by day 1, and 22 (51%) had > 10% cumulative FO by day 3. Following phase 1 of the VSAP, the frequency of daily weight orders increased from 6% to 88%.

Conclusions:

In our institution, use of fluid monitoring tools is both inconsistent and infrequent. Early data from the VSAP project suggests simple interventions can modify ordering and monitoring practice, but future improvement cycles are necessary to determine if these changes are successful in reducing iatrogenic FO

Risk factors and outcomes for airway failure versus non-airway failure in the intensive care unit: a multicenter observational study of 1514 extubation procedures

BACKGROUND

Patients liberated from invasive mechanical ventilation are at risk of extubation failure, including inability to breathe without a tracheal tube (airway failure) or without mechanical ventilation (non-airway failure). We sought to identify respective risk factors for airway failure and non-airway failure following extubation.

METHODS

The primary endpoint of this prospective, observational, multicenter study in 26 intensive care units was extubation failure, defined as need for reintubation within 48 h following extubation. A multinomial logistic regression model was used to identify risk factors for airway failure and non-airway failure.

RESULTS

Between 1 December 2013 and 1 May 2015, 1514 patients undergoing extubation were enrolled. The extubation-failure rate was 10.4% (157/1514), including 70/157 (45%) airway failures, 78/157 (50%) non-airway failures, and 9/157 (5%) mixed airway and non-airway failures. By multivariable analysis, risk factors for extubation failure were either common to airway failure and non-airway failure: intubation for coma (OR 4.979 (2.797-8.864), P < 0.0001 and OR 2.067 (1.217-3.510), P = 0.003, respectively, intubation for acute respiratory failure (OR 3.395 (1.877-6.138), P < 0.0001 and OR 2.067 (1.217-3.510), P = 0.007, respectively, absence of strong cough (OR 1.876 (1.047-3.362), P = 0.03 and OR 3.240 (1.786-5.879), P = 0.0001, respectively, or specific to each specific mechanism: female gender (OR 2.024 (1.187-3.450), P = 0.01), length of ventilation > 8 days (OR 1.956 (1.087-3.518), P = 0.025), copious secretions (OR 4.066 (2.268-7.292), P < 0.0001) were specific to airway failure, whereas non-obese status (OR 2.153 (1.052-4.408), P = 0.036) and sequential organ failure assessment (SOFA) score ≥ 8 (OR 1.848 (1.100-3.105), P = 0.02) were specific to non-airway failure. Both airway failure and non-airway failure were associated with ICU mortality (20% and 22%, respectively, as compared to 6% in patients with extubation success, P < 0.0001).

CONCLUSIONS

Specific risk factors have been identified, allowing us to distinguish between risk of airway failure and non-airway failure. The two conditions will be managed differently, both for prevention and curative strategies.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT 02450669 . Registered on 21 May 2015.

Furosemide and Albumin for Diuresis of Edema (FADE): A parallel-group, blinded, pilot randomized controlled trial

PURPOSE

To assess the feasibility of a trial evaluating whether hyperoncotic albumin, in addition to diuretics, improves diuresis and facilitates liberation from mechanical ventilation in critically ill adults.

MATERIALS AND METHODS

We randomized 46 hemodynamically stable patients with hypoalbuminemia, prescribed diuretics by treating clinicians, to receive 100 mL of 25% albumin or 0.9% saline placebo BID, for three days, in blinded fashion. We chose five feasibility measurements: enrolment of 50% of eligible patients, at least one patient/week; administration of study treatment within 2 h of diuretics in 85% of patients; completion of study regimen in 80% of patients; and avoidance of open label albumin in 85% of patients. Clinical outcomes included fluid balance, ventilator-free days, and mortality.

RESULTS

We randomized 85% of eligible patients. Eighty-four percent received study treatment within 2 h of diuretics, 69% received all doses of study treatment. Study treatment was held in the albumin and placebo groups because of no further need for diuresis (4 vs. 1), hypotension (2 v. 4), and albumin > 35 (1 v. 0). Twenty percent of patients received open-label albumin. Clinical outcomes were similar between groups.

CONCLUSIONS

The current study design did not demonstrate feasibility, but can inform the design of a definitive trial.

Association Between Fluid Balance and Outcomes in Critically Ill Children: A Systematic Review and Meta-analysis

IMPORTANCE

After initial resuscitation, critically ill children may accumulate fluid and develop fluid overload. Accruing evidence suggests that fluid overload contributes to greater complexity of care and worse outcomes.

OBJECTIVE

To describe the methods to measure fluid balance, define fluid overload, and evaluate the association between fluid balance and outcomes in critically ill children.

DATA SOURCES

Systematic search of MEDLINE, EMBASE, Cochrane Library, trial registries, and selected gray literature from inception to March 2017.

STUDY SELECTION

Studies of children admitted to pediatric intensive care units that described fluid balance or fluid overload and reported outcomes of interest were included. No language restrictions were applied.

DATA EXTRACTION AND SYNTHESIS

All stages were conducted independently by 2 reviewers. Data extracted included study characteristics, population, fluid metrics, and outcomes. Risk of bias was assessed using the Newcastle-Ottawa Scale. Narrative description of fluid assessment methods and fluid overload definitions was done. When feasible, pooled analyses were performed using random-effects models.

MAIN OUTCOMES AND MEASURES

Mortality was the primary outcome. Secondary outcomes included treatment intensity, organ failure, and resource use.

RESULTS

A total of 44 studies (7507 children) were included in this systematic review and meta-analysis. Of those, 27 (61%) were retrospective cohort studies, 13 (30%) were prospective cohort studies, 3 (7%) were case-control studies, and 1 study (2%) was a secondary analysis of a randomized trial. The proportion of children with fluid overload varied by case mix and fluid overload definition (median, 33%; range, 10%-83%). Fluid overload, however defined, was associated with increased in-hospital mortality (17 studies [n = 2853]; odds ratio [OR], 4.34 [95% CI, 3.01-6.26]; I2 = 61%). Survivors had lower percentage fluid overload than nonsurvivors (22 studies [n = 2848]; mean difference, -5.62 [95% CI, -7.28 to -3.97]; I2 = 76%). After adjustment for illness severity, there was a 6% increase in odds of mortality for every 1% increase in percentage fluid overload (11 studies [n = 3200]; adjusted OR, 1.06 [95% CI, 1.03-1.10]; I2 = 66%). Fluid overload was associated with increased risk for prolonged mechanical ventilation (>48 hours) (3 studies [n = 631]; OR, 2.14 [95% CI, 1.25-3.66]; I2 = 0%) and acute kidney injury (7 studies [n = 1833]; OR, 2.36 [95% CI, 1.27-4.38]; I2 = 78%).

CONCLUSIONS AND RELEVANCE

Fluid overload is common and is associated with substantial morbidity and mortality in critically ill children. Additional research should now ideally focus on interventions aimed to mitigate the potential for harm associated with fluid overload.

Fluid Overload and Renal Angina Index at Admission Are Associated With Worse Outcomes in Critically Ill Children

Objectives: We investigated the association of fluid overload and oxygenation in critically sick children, and their correlation with various outcomes (duration of ventilation, ICU stay, and mortality). We also assessed whether renal angina index (RAI) at admission can predict mortality or acute kidney injury (AKI) on day 3 after admission. Design and setting: Prospective study, pediatric intensive care in a tertiary hospital. Duration: June 2013-June 2014. Patients: Patients were included if they needed invasive mechanical ventilation for >24 h and had an indwelling arterial catheter. Patients with congenital heart disease or those who received renal replacement therapy (RRT) were excluded. Methods: Oxygenation index, fluid overload percent (daily, cumulative), RAI at admission and pediatric logistic organ dysfunction (PELOD) score were obtained in all critically ill children. KDIGO classification was used to define AKI, using both creatinine and urine output criteria. Admission data for determination of RAI included the use of vasopressors, invasive mechanical ventilation, percent fluid overload, and change in kidney function (estimated creatinine clearance). Univariable and multivariable approaches were used to assess the relations between fluid overload, oxygenation index and clinical outcomes. An RAI cutoff >8 was used to predict AKI on day 3 of admission and mortality. Results: One hundred and two patients were recruited. Fluid overload predicted oxygenation index in all patients, independent of age, gender and PELOD score (p < 0.05). Fluid overload was associated with longer duration of ventilation (p < 0.05), controlled for age, gender, and PELOD score. Day-3 AKI rates were higher in patients with a RAI of 8 or more, and higher areas under the RAI curve had better prediction rates for Day-3 AKI. An RAI <8 had high negative predictive values (80-95%) for Day-3 AKI. RAI was better than traditional markers of pediatric severity of illness (PELOD) score for prediction of AKI on day 3. Conclusions: This study emphasizes that positive fluid balance adversely affects intensive care in critically ill children. Further, the RAI prediction model may help optimize treatment and improve clinical prediction of AKI.

The effect of low-dose furosemide in critically ill patients with early acute kidney injury: A pilot randomized blinded controlled trial (the SPARK study)

PURPOSE

Furosemide is commonly prescribed in acute kidney injury (AKI). Prior studies have found conflicting findings on whether furosemide modifies the course and outcome of AKI.

METHODS

Pilot multi-center randomized blinded placebo-controlled trial in adult patients with AKI admitted to three intensive care units. Participants were randomly allocated to furosemide bolus and infusion or 0.9% saline placebo. Primary endpoint was worsening AKI, defined by the RIFLE criteria. Secondary endpoints were kidney recovery, renal replacement therapy (RRT) and adverse events.

RESULTS

The trial was terminated after enrollment of 73 participants (37 to furosemide and 36 to placebo). Mean (SD) age was 61.7 (14.3), 79.5% were medical admissions, mean (SD) APACHE II score was 26.6 (7.8), 90.4% received mechanical ventilation and 61.6% received vasoactives. Groups were similar at baseline. No differences were found in the proportion with worsening AKI (43.2% vs. 37.1%, p=0.6), kidney recovery (29.7% vs. 42.9%, p=0.3), or RRT (27.0% s. 28.6%, p=0.8). Adverse events, mostly electrolyte abnormalities, were more common in furosemide-treated patients (p<0.001). Protocol deviations were common, due often to supplementary furosemide.

CONCLUSIONS

In this pilot trial, furosemide did not reduce the rate of worsening AKI, improve recovery or reduce RRT; however, was associated with greater electrolyte abnormalities.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00978354 registered September 9, 2014.

Passive Leg Raising: Simple and Reliable Technique to Prevent Fluid Overload in Critically ill Patients

Background:

Dynamic measures, the response to stroke volume (SV) to fluid loading, have been used successfully to guide fluid management decisions in critically ill patients. However, application of dynamic measures is often inaccurate to predict fluid responsiveness in patients with arrhythmias, ventricular dysfunction or spontaneously breathing critically ill patients. Passive leg raising (PLR) is a simple bedside maneuver that may provide an accurate alternative to guide fluid resuscitation in hypovolemic critically ill patients.

Methods:

Pertinent medical literature for fluid responsiveness in the critically ill patient published in English was searched over the past three decades, and then the search was extended as linked citations indicated.

Results:

Thirty-three studies including observational studies, randomized control trials, systemic review, and meta-analysis studies evaluating fluid responsiveness in the critically ill patient met selection criteria.

Conclusions:

PLR coupled with real-time SV monitors is considered a simple, noninvasive, and accurate method to determine fluid responsiveness in critically ill patients with high sensitivity and specificity for a 10% increase in SV. The adverse effect of albumin on the mortality of head trauma patients and chloride-rich crystalloids on mortality and kidney function needs to be considered when choosing the type of fluid for resuscitation.

Fluid Management for Critically Ill Patients: A Review of the Current State of Fluid Therapy in the Intensive Care Unit

BACKGROUND

Intravenous fluids (IVF) are frequently utilized to restore intravascular volume in patients with distributive and hypovolemic shock. Although the benefits of the appropriate use of fluids in intensive care units (ICUs) and hospitals are well described, there is growing knowledge regarding the potential risks of volume overload and its impact on organ failure and mortality. To avoid volume overload and its associated complications, strategies to identify fluid responsiveness are developed and utilized more often among ICU patients. Apart from the amount of fluid utilized for resuscitation, the type of fluid used also impacts patient outcome. Colloids and crystalloids are two types of fluids that are utilized for resuscitation. The efficacy of each fluid type on the expansion of intravascular volume on one hand and the potential adverse effects of each individual fluid, on the other hand, need to be considered when choosing the type of fluid for resuscitation. The negative impact of hydroxyethyl starch on kidney function, of albumin on the mortality of head trauma patients and chloride-rich crystalloids on mortality and kidney function, are only examples of new developments in the field.

SUMMARY

In this paper, we will review the impact of fluid overload on patient outcomes, define the fluid challenge, describe the differences in static and dynamic estimates of fluid responsiveness, and review the effect of different types of fluid on patient outcome.

KEY MESSAGE

Avoiding fluid overload by choosing the appropriate amount of fluids in patients who are fluid-responsive on one hand, and treating IVF like other medications, on the other hand, are the major changes. Whenever clinicians decide to prescribe IVF, they need to weigh the risks and benefits of giving fluid and also the advantages and side effects of each fluid type in order to optimize patient outcomes.

Impact of positive fluid balance on mortality and length of stay in septic shock patients

BACKGROUND

Fluid management is important in critically patients. The aim of this study was to determine the relationship between fluid balance and adverse outcomes of septic shock.

METHODS

A retrospective study was conducted in the medical Intensive Care Unit (ICU) of a tertiary university hospital in Thailand, over a 7-year period.

RESULTS

A total of 1048 patients with an ICU mortality rate of 47% were enrolled. The median cumulative fluid intake at 24, 48, and 72 h from septic shock onset were 4.2, 7.7, and 10.5 L, respectively. Nonsurvivors had a significantly higher median cumulative fluid intake at 24, 48, and 72 h (4.6 vs. 3.9 L, 8.2 vs. 7.1 L, and 11.4 vs. 9.9 L, respectively, P < 0.001 for all). Nonsurvivors also had a significantly higher cumulative and mean fluid balance within 72 h (5.4 vs. 4.4 L and 2.8 vs. 1.6 L, P < 0.001 for both). In multivariate logistic regression analysis, mean fluid balance quartile within 72 h, was independently associated with an increase in ICU and hospital mortality. Quartile 3 and 4 have statistically significant increases in mortality compared with quartile 1 (odds ratio [95% confidence interval] 3.04 [1.9-4.48] and 4.16 [2.49-6.95] for ICU mortality and 2.75 [1.74-4.36] and 3.16 [1.87-5.35] for hospital mortality, respectively, P < 0.001 for all). In addition, the higher amount of mean fluid balance was associated with prolonged ICU stays.

CONCLUSIONS

Positive fluid balance over 3 days is associated with increased ICU and hospital mortality along with prolonged ICU stays in septic shock patients.

How to avoid fluid overload

PURPOSE OF REVIEW

This review highlights the recent evidence describing the outcomes associated with fluid overload in critically ill patients and provides an overview of fluid management strategies aimed at preventing fluid overload during the resuscitation of patients with shock.

RECENT FINDINGS

Fluid overload is a common complication of fluid resuscitation and is associated with increased hospital costs, morbidity and mortality.

SUMMARY

Fluid management goals differ during the resuscitation, optimization, stabilization and evacuation phases of fluid resuscitation. To prevent fluid overload, strategies that reduce excessive fluid infusions and emphasize the removal of accumulated fluids should be implemented.

Fluid management in abdominal surgery: what, when, and when not to administer

The entire team (including anesthesiologists, surgeons, and intensive care physicians) must work together (before, during, and after abdominal surgery) to determine the optimal amount (quantity) and type (quality) of fluid necessary in the perioperative period. The authors present an overview of the basic principles that underlie fluid management, including evidence-based recommendations (where tenable) and a rational approach for when and what to administer.

Peri-operative intensive care

All good intensive care requires attention to detail of the routine elements of care. These include staffing and monitoring, drug prescription and administration, feeding and fluid balance, analgesia and sedation, organ support and reducing the risk of healthcare-associated infection. Doing this well requires an understanding of the relevant physiology and an awareness of the limited evidence base. Detailed protocols and implementation checklist are valuable in ensuring that these minimum standards are met. However, peri-operative care is not all predictable and amenable to protocolization. This is especially true following separation of conjoined twins. Despite the sophisticated imaging and multi-disciplinary planning that precede elective separation, the acute physiological changes in each twin cannot always be predicted reliably. In this article, we review briefly each element of peri-operative care and how this might vary in conjoined twins.

Principles of Fluid Management

Fluid therapy is the most common intervention received by acutely ill hospitalized patients; however, important questions on its optimal use remain. Its prescription should be patient and context specific, with clear indications and contradictions, and have the type, dose, and rate specified. Any fluid therapy, if provided inappropriately, can contribute unnecessary harm to patients. The quantitative toxicity of fluid therapy contributes to worse outcomes; this should prompt greater bedside attention to fluid prescription, fluid balance, development of avoidable complications attributable to fluid overload, and for the timely deresuscitation of patients whose clinical status and physiology allow active fluid mobilization.

Fluid Overload

Most critically ill patients experience external or internal fluid shifts and hemodynamic instability. In response to these changes, intravenous fluids are frequently administered. However, rapid losses of administered fluids from circulation and the indirect link between the short-lived plasma volume expansion and end points frequently result in transient responses to fluid therapy. Therefore, fluid overload is a common finding in intensive care units. The authors consider the evidence of harm associated with fluid overload and the physiologic processes that lead to fluid accumulation in critical illness. The authors then consider methods to prevent fluid accumulation and/or manage its resolution.

In Vivo Evaluation of the Ameliorating Effects of Small-Volume Resuscitation with Four Different Fluids on Endotoxemia-Induced Kidney Injury

Acute kidney injury associated with renal hypoperfusion is a frequent and severe complication during sepsis. Fluid resuscitation is the main therapy. However, heart failure is usually lethal for those patients receiving large volumes of fluids. We compared the effects of small-volume resuscitation using four different treatment regimens, involving saline, hypertonic saline (HTS), hydroxyethyl starch (HES), or hypertonic saline hydroxyethyl starch (HSH), on the kidneys of rats treated with lipopolysaccharide (LPS) to induce endotoxemia. LPS injection caused reduced and progressively deteriorated systemic (arterial blood pressure) and renal hemodynamics (renal blood flow and renal vascular resistance index) over time. This deterioration was accompanied by marked renal functional and pathological injury, as well as an oxidative and inflammatory response, manifesting as increased levels of tumor necrosis factor-α, nitric oxide, and malondialdehyde and decreased activity of superoxide dismutase. Small-volume perfusion with saline failed to improve renal and systemic circulation. However, small-volume perfusion with HES and HSH greatly improved the above parameters, while HTS only transiently improved systemic and renal hemodynamics with obvious renal injury. Therefore, single small-volume resuscitation with HES and HSH could be valid therapeutic approaches to ameliorate kidney injury induced by endotoxemia, while HTS transiently delays injury and saline shows no protective effects.

Indications and management of mechanical fluid removal in critical illness

BACKGROUND

The Acute Dialysis Quality Initiative (ADQI) dedicated its Twelfth Consensus Conference (2013) to all aspects of fluid therapy, including the management of fluid overload (FO). The aim of the working subgroup 'Mechanical fluid removal' was to review the indications, prescription, and management of mechanical fluid removal within the broad context of fluid management of critically ill patients.

METHODS

The working group developed a list of preliminary questions and objectives and performed a modified Delphi analysis of the existing literature. Relevant studies were identified through a literature search using the MEDLINE database and bibliographies of relevant research and review articles.

RESULTS

After review of the existing literature, the group agreed the following consensus statements: (i) in critically ill patients with FO and with failure of or inadequate response to pharmacological therapy, mechanical fluid removal should be considered as a therapy to optimize fluid balance. (ii) When using mechanical fluid removal or management, targets for rate of fluid removal and net fluid removal should be based upon the overall fluid balance of the patient and also physiological variables, individualized, and reassessed frequently. (iii) More research on the role and practice of mechanical fluid removal in critically ill patients not meeting fluid balance goals (including in children) is necessary.

CONCLUSION

Mechanical fluid removal should be considered as a therapy for FO, but more research is necessary to determine its exact role and clinical application.