Should chloride-rich crystalloids remain the mainstay of fluid resuscitation to prevent 'pre-renal' acute kidney injury?: con

Balanced Crystalloids Versus Normal Saline in Kidney Transplant Patients: An Updated Systematic Review, Meta-analysis, and Trial Sequential Analysis

BACKGROUND

The use of balanced crystalloids over normal saline for perioperative fluid management during kidney transplantation and its benefits on acid-base and electrolyte balance along with its influence on postoperative clinical outcomes remains a topic of controversy. Therefore, we conducted this review to assess the impact of balanced solutions compared to normal saline on outcomes for kidney transplant patients.

METHODS

We searched MEDLINE, EMBASE, and Cochrane databases for randomized controlled trials (RCTs) comparing balanced lower-chloride solutions to normal saline in renal transplant patients. Our main outcome of interest was delayed graft function (DGF). Additionally, we examined acid-base and electrolyte measurements, along with postoperative renal function. We computed relative risk (RR) using the Mantel-Haenszel test for binary outcomes, and mean difference (MD) for continuous data, and applied DerSimonian and Laird random-effects models to address heterogeneity. Furthermore, we performed a trial sequential analysis (TSA) for all outcomes.

RESULTS

Twelve RCTs comprising a total of 1668 patients were included; 832 (49.9%) were assigned to receive balanced solutions. Balanced crystalloids reduced the occurrence of DGF compared to normal saline, with RR of 0.82 (95% confidence interval [CI], 0.71-0.94), P = .005; I² = 0%. The occurrence was 25% (194 of 787) in the balanced crystalloids group and 34% (240 of 701) in the normal saline group. Moreover, our TSA supported the primary outcome result and suggests that the sample size was sufficient for our conclusion. End-of-surgery chloride (MD, -8.80 mEq·L -1 ; 95% CI, -13.98 to -3.63 mEq.L -1 ; P < .001), bicarbonate (MD, 2.12 mEq·L -1 ; 95% CI, 1.02-3.21 mEq·L -1 ; P < .001), pH (MD, 0.06; 95% CI, 0.04-0.07; P < .001), and base excess (BE) (MD, 2.41 mEq·L -1 ; 95% CI, 0.88-3.95 mEq·L -1 ; P = .002) significantly favored the balanced crystalloids groups and the end of surgery potassium (MD, -0.17 mEq·L -1 ; 95% CI, -0.36 to 0.02 mEq·L -1 ; P = .07) did not differ between groups. However, creatinine did not differ in the first (MD, -0.06 mg·dL -1 ; 95% CI, -0.38 to 0.26 mg·dL -1 ; P = .71) and seventh (MD, -0.06 mg·dL -1 ; 95% CI, -0.18 to 0.06 mg·dL -1 ; P = .30) postoperative days nor urine output in the first (MD, -1.12 L; 95% CI, -3.67 to 1.43 L; P = .39) and seventh (MD, -0.01 L; 95% CI, -0.45 to 0.42 L; P = .95) postoperative days.

CONCLUSIONS

Balanced lower-chloride solutions significantly reduce the occurrence of DGF and provide an improved acid-base and electrolyte control in patients undergoing kidney transplantation.

Assessment of pre-, peri-, and post-surgical practices for elective colorectal patients in a model 4 hospital in Ireland

INTRODUCTION

The ERAS protocol is a set of international guidelines established to expedite patients' discharge after colorectal surgery. It does this by aiming to prevent postoperative complications early, and return the patient to normal function allowing earlier discharge. Complications such as PONV, DVT, ileus and pain are common after surgery to name a few, and delay discharge. Early treatment and prevention of these complications however is suggested to aid a patients' return to home at earlier rates than traditional practice.

METHODS

A prospective chart review and questionnaire was performed on patients undergoing colorectal surgery in UHL in a 6-month period from February to September 2023. Patients were approached on the 3rd day postoperatively and informed about the project. Exclusion criteria included patients who went to HDU or ICU postoperatively.

RESULTS

In total, 33 patients were recruited. A target of greater than 70% compliance was reached for a variety of the elements of the ERAS protocol such as laparoscopic surgery, preoperative assessments, nutritional drinks, LMWH, oral intake within 24 h of surgery, and intraoperative antiemetics. Unsatisfactory compliance was found with documentation of postoperative antibiotics use of preoperative gabapentin.

CONCLUSION

UHL has a satisfactory compliance of over 70% with a large variety of elements of the ERAS protocol. Areas of improvement required include postoperative antibiotic and preoperative gabapentin usage. With the collective effort of the multidisciplinary team, along with education, the ERAS protocol can successfully be applied and implemented in a model 4 hospital in Ireland.

The effect of goal-directed fluid therapy on delayed graft function in kidney transplant recipients: A systematic review and meta-analysis

Delayed graft function (DGF) is a common post-operative complication with potential long-term sequelae for many kidney transplant recipients, and hemodynamic factors and fluid status play a role. Fixed perioperative fluid infusions are the standard of care, but more recent evidence in the non-transplant population has suggested benefit with goal-directed fluid strategies based on hemodynamic targets. We searched MEDLINE, EMBASE, Cochrane Controlled Trials Registry and Google Scholar through December 2022 for randomized controlled trials comparing risk of DGF between goal-directed and conventional fluid therapy in adults receiving a living or deceased donor kidney transplant. Effect estimates were reported with odds ratios (OR) and pooled using random effects meta-analysis. We identified 4 studies (205 participants) that met the inclusion criteria. The use of goal-directed fluid therapy had no significant effect on DGF (OR 1.37 95% CI, 0.34-5.6; p = 0.52; I2 = 0.11). Subgroup analysis examining effects among deceased and living kidney donation did not reveal significant differences in the effects of fluid strategy on DGF between subgroups. Overall, the strength of the evidence for goal-directed versus conventional fluid therapy to reduce DGF was of low certainty. Our findings highlight the need for larger trials to determine the effect of goal-directed fluid therapy on this patient-centered outcome.

The effect of dehydration, hyperchloremia and volume of fluid resuscitation on acute kidney injury in children admitted to hospital with diabetic ketoacidosis

BACKGROUND

Acute kidney injury (AKI) is a recognized comorbidity in pediatric diabetic ketoacidosis (DKA), although the exact etiology is unclear. The unique physiology of DKA makes dehydration assessments challenging, and these patients potentially receive excessive amounts of intravenous fluids (IVF). We hypothesized that dehydration is over-estimated in pediatric DKA, leading to over-administration of IVF and hyperchloremia that worsens AKI.

METHODS

Retrospective cohort of all DKA inpatients at a tertiary pediatric hospital from 2014 to 2019. A total of 145 children were included; reasons for exclusion were pre-existing kidney disease or incomplete medical records. AKI was determined by change in creatinine during admission, and comparison to a calculated baseline value. Linear regression multivariable analysis was used to identify factors associated with AKI. True dehydration was calculated from patients' change in weight, as previously validated. Fluid over-resuscitation was defined as total fluids given above the true dehydration.

RESULTS

A total of 19% of patients met KDIGO serum creatinine criteria for AKI on admission. Only 2% had AKI on hospital discharge. True dehydration and high serum urea levels were associated with high serum creatinine levels on admission (p = 0.042; p < 0.001, respectively). Fluid over-resuscitation and hyperchloremia were associated with delayed kidney recovery (p < 0.001). Severity of initial AKI was associated with cerebral edema (p = 0.018).

CONCLUSIONS

Dehydration was associated with initial AKI in children with DKA. Persistent AKI and delay to recovery was associated with hyperchloremia and over-resuscitation with IVF, potentially modifiable clinical variables for earlier AKI recovery and reduction in long-term morbidity. This highlights the need to re-address fluid protocols in pediatric DKA.

A Comprehensive Review of Chloride Management in Critically Ill Patients

Chloride, often overshadowed in electrolyte management, emerges as a crucial player in the physiological intricacies of critically ill patients. This comprehensive review explores the multifaceted aspects of chloride, ranging from its significance in cellular homeostasis to the consequences of dysregulation in critically ill patients. The pathophysiology of hyperchloremia and hypochloremia is dissected, highlighting their intricate impact on acid-base balance, renal function, and cardiovascular stability. Clinical assessment strategies, including laboratory measurements and integration with other electrolytes, lay the foundation for targeted interventions. Consequences of dysregulated chloride levels underscore the need for meticulous management, leading to an exploration of emerging therapies and interventions. Fluid resuscitation protocols, the choice between crystalloids and colloids, the role of balanced solutions, and individualized patient approaches comprise the core strategies in chloride management. Practical considerations, such as monitoring and surveillance, overcoming implementation challenges, and embracing a multidisciplinary approach, are pivotal in translating theoretical knowledge into effective clinical practice. As we envision the future, potential impacts on critical care guidelines prompt reflections on integrating novel therapies, individualized approaches, and continuous monitoring practices. In conclusion, this review synthesizes current knowledge, addresses practical considerations, and envisions future directions in chloride management for critically ill patients. By embracing a holistic understanding, clinicians can navigate the complexities of chloride balance, optimize patient outcomes, and contribute to the evolving landscape of critical care medicine.

The 2023 Sir David Cuthbertson Lecture. A fluid journey: Experiments that influenced clinical practice

This review summarises some of my work on fluid and electrolyte balance over the past 25 years and shows how the studies have influenced clinical practice. Missing pieces in the jigsaw are filled in by summarising the work of others. The main theme is the biochemical, physiological and clinical problems caused by inappropriate use of saline solutions including the hyperchloraemic acidosis caused by 0.9% saline. The importance of accurate and near-zero fluid balance in clinical practice is also emphasised. Perioperative fluid and electrolyte therapy has important effects on clinical outcome in a U-shaped dose response fashion, in which excess or deficit progressively increases complications and worsens outcome. Salt and water overload, with weight gain in excess of 2.5 kg worsens surgical outcome, impairs gastrointestinal function and increases the risk of anastomotic dehiscence. Hyperchloraemic acidosis caused by overenthusiastic infusion of 0.9% saline leads to adverse outcomes and dysfunction of many organ systems, especially the kidney. Salt and water deficit causes similar adverse effects as fluid overload at the cellular level and also leads to worse outcomes. Serum albumin is shown to be affected mainly by dilution and inflammation and is not a good nutritional marker. These findings have been incorporated in the British consensus Guidelines on Intravenous Fluid Therapy for Adult Surgical Patients (GIFTASUP) and National Institute for Health and Care Excellence (NICE) guidelines on intravenous fluid therapy in adults in hospital and are helping change clinical practice and improve outcomes.

Consensus Guidelines for Perioperative Care for Emergency Laparotomy Enhanced Recovery After Surgery (ERAS®) Society Recommendations Part 2-Emergency Laparotomy: Intra- and Postoperative Care

BACKGROUND

This is Part 2 of the first consensus guidelines for optimal care of patients undergoing emergency laparotomy (EL) using an Enhanced Recovery After Surgery (ERAS) approach. This paper addresses intra- and postoperative aspects of care.

METHODS

Experts in aspects of management of high-risk and emergency general surgical patients were invited to contribute by the International ERAS® Society. PubMed, Cochrane, Embase, and Medline database searches were performed for ERAS elements and relevant specific topics. Studies on each item were selected with particular attention to randomized clinical trials, systematic reviews, meta-analyses, and large cohort studies and reviewed and graded using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Recommendations were made on the best level of evidence, or extrapolation from studies on elective patients when appropriate. A modified Delphi method was used to validate final recommendations. Some ERAS® components covered in other guideline papers are outlined only briefly, with the bulk of the text focusing on key areas pertaining specifically to EL.

RESULTS

Twenty-three components of intraoperative and postoperative care were defined. Consensus was reached after three rounds of a modified Delphi Process.

CONCLUSIONS

These guidelines are based on best available evidence for an ERAS® approach to patients undergoing EL. These guidelines are not exhaustive but pull together evidence on important components of care for this high-risk patient population. As much of the evidence is extrapolated from elective surgery or emergency general surgery (not specifically laparotomy), many of the components need further evaluation in future studies.

Balanced crystalloid solution versus saline in deceased donor kidney transplantation (BEST-Fluids): a pragmatic, double-blind, randomised, controlled trial

BACKGROUND

Delayed graft function (DGF) is a major adverse complication of deceased donor kidney transplantation. Intravenous fluids are routinely given to patients receiving a transplant to maintain intravascular volume and optimise graft function. Saline (0·9% sodium chloride) is widely used but might increase the risk of DGF due to its high chloride content. We aimed to test our hypothesis that using a balanced low-chloride crystalloid solution (Plasma-Lyte 148) instead of saline would reduce the incidence of DGF.

METHODS

BEST-Fluids was a pragmatic, registry-embedded, multicentre, double-blind, randomised, controlled trial at 16 hospitals in Australia and New Zealand. Adults and children of any age receiving a deceased donor kidney transplant were eligible; those receiving a multi-organ transplant or weighing less than 20 kg were excluded. Participants were randomly assigned (1:1) using an adaptive minimisation algorithm to intravenous balanced crystalloid solution (Plasma-Lyte 148) or saline during surgery and up until 48 h after transplantation. Trial fluids were supplied in identical bags and clinicians determined the fluid volume, rate, and time of discontinuation. The primary outcome was DGF, defined as receiving dialysis within 7 days after transplantation. All participants who consented and received a transplant were included in the intention-to-treat analysis of the primary outcome. Safety was analysed in all randomly assigned eligible participants who commenced surgery and received trial fluids, whether or not they received a transplant. This study is registered with Australian New Zealand Clinical Trials Registry, (ACTRN12617000358347), and ClinicalTrials.gov (NCT03829488).

FINDINGS

Between Jan 26, 2018, and Aug 10, 2020, 808 participants were randomly assigned to balanced crystalloid (n=404) or saline (n=404) and received a transplant (512 [63%] were male and 296 [37%] were female). One participant in the saline group withdrew before 7 days and was excluded, leaving 404 participants in the balanced crystalloid group and 403 in the saline group that were included in the primary analysis. DGF occurred in 121 (30%) of 404 participants in the balanced crystalloid group versus 160 (40%) of 403 in the saline group (adjusted relative risk 0·74 [95% CI 0·66 to 0·84; p<0·0001]; adjusted risk difference 10·1% [95% CI 3·5 to 16·6]). In the safety analysis, numbers of investigator-reported serious adverse events were similar in both groups, being reported in three (<1%) of 406 participants in the balanced crystalloid group versus five (1%) of 409 participants in the saline group (adjusted risk difference -0·5%, 95% CI -1·8 to 0·9; p=0·48).

INTERPRETATION

Among patients receiving a deceased donor kidney transplant, intravenous fluid therapy with balanced crystalloid solution reduced the incidence of DGF compared with saline. Balanced crystalloid solution should be the standard-of-care intravenous fluid used in deceased donor kidney transplantation.

FUNDING

Medical Research Future Fund and National Health and Medical Research Council (Australia), Health Research Council (New Zealand), Royal Australasian College of Physicians, and Baxter.

Serum Chloride and Heart Failure

Despite significant advances in management, heart failure continues to impose a significant epidemiologic burden with high prevalence and mortality rates. For decades, sodium has been the serum electrolyte most commonly associated with outcomes; however, challenging the conventional paradigm of sodium's influence, recent studies have identified a more prominent role in serum chloride in the pathophysiology of heart failure. More specifically, hypochloremia is associated with neurohumoral activation, diuretic resistance, and a worse prognosis in patients with heart failure. This review examines basic science, translational research, and clinical studies to better characterize the role of chloride in patients with heart failure and additionally discusses potential new therapies targeting chloride homeostasis that may impact the future of heart failure care.

Fluid bolus therapy in pediatric sepsis: a narrative review

Leading cause of death in children under five, pediatric sepsis remains a significant global health threat. The 2020 Surviving Sepsis Campaign guidelines revised the management of septic shock and sepsis-associated organ dysfunction in children. In addition to empiric broad-spectrum antibiotics, fluid bolus therapy is one of the cornerstones of management, due to theoretical improvement of cardiac output, oxygen delivery and organ perfusion. Despite a very low level of evidence, the possible benefit of balanced crystalloids in sepsis resuscitation has led to discussion on their position as the ideal fluid. However, the latest adult data are not consistent with this, and the debate is still ongoing in pediatrics. We provide here the current state of knowledge on fluid bolus therapy in pediatric sepsis with emphasis on balanced crystalloids.

Baseline Characteristics and Representativeness of Participants in the BEST-Fluids Trial: A Randomized Trial of Balanced Crystalloid Solution Versus Saline in Deceased Donor Kidney Transplantation

Delayed graft function (DGF) is a major complication of deceased donor kidney transplantation. Saline (0.9% sodium chloride) is a commonly used intravenous fluid in transplantation but may increase the risk of DGF because of its high chloride content. Better Evidence for Selecting Transplant Fluids (BEST-Fluids), a pragmatic, registry-based, double-blind, randomized trial, sought to determine whether using a balanced low-chloride crystalloid solution (Plasma-Lyte 148) instead of saline would reduce DGF. We sought to evaluate the generalizability of the trial cohort by reporting the baseline characteristics and representativeness of the trial participants in detail.

METHODS

We compared the characteristics of BEST-Fluids participants with those of a contemporary cohort of deceased donor kidney transplant recipients in Australia and New Zealand using data from the Australia and New Zealand Dialysis and Transplant Registry. To explore potential international differences, we compared trial participants with a cohort of transplant recipients in the United States using data from the Scientific Registry of Transplant Recipients.

RESULTS

During the trial recruitment period, 2373 deceased donor kidney transplants were performed in Australia and New Zealand; 2178 were eligible' and 808 were enrolled in BEST-Fluids. Overall, trial participants and nonparticipants were similar at baseline. Trial participants had more coronary artery disease (standardized difference [d] = 0.09; P = 0.03), longer dialysis duration (d = 0.18, P < 0.001), and fewer hypertensive (d = -0.11, P = 0.03) and circulatory death (d = -0.14, P < 0.01) donors than nonparticipants. Most key characteristics were similar between trial participants and US recipients, with moderate differences (|d| ≥ 0.2; all P < 0.001) in kidney failure cause, diabetes, dialysis duration, ischemic time, and several donor risk predictors, likely reflecting underlying population differences.

CONCLUSIONS

BEST-Fluids participants had more comorbidities and received slightly fewer high-risk deceased donor kidneys but were otherwise representative of Australian and New Zealand transplant recipients and were generally similar to US recipients. The trial results should be broadly applicable to deceased donor kidney transplantation practice worldwide.

Fluid Stewardship of Maintenance Intravenous Fluids

Despite the frequent use of maintenance intravenous fluids (mIVF) in critically ill patients, limited guidance is available. Notably, fluid overload secondary to mIVF mismanagement is associated with significant adverse patient outcomes. The Four Rights (right drug, right dose, right duration, right patient) construct of fluid stewardship has been proposed for the safe evaluation and use of fluids. The purpose of this evidence-based review is to offer practical insights for the clinician regarding mIVF selection, dosing, and duration in line with the Four Rights of Fluid Stewardship.

The management and diagnosis of rhabdomyolysis-induced acute kidney injury: a case study

Rhabdomyolysis is characterised by a rapid dissolution of damaged or injured skeletal muscle that can be the result of a multitude of mechanisms. It can range in severity from mild to severe, leading to multi-organ failure and death. Rhabdomyolysis causes muscular cellular breakdown, which can cause fatal electrolyte imbalances and metabolic acidosis, as myoglobin, creatine phosphokinase, lactate dehydrogenase and other electrolytes move into the circulation; acute kidney injury can follow as a severe complication. This article reflects on the case of a person who was diagnosed with rhabdomyolysis and acute kidney injury after a fall at home. Understanding the underpinning mechanism of rhabdomyolysis and the associated severity of symptoms may improve early diagnosis and treatment initiation.

Introducing isotonic fluids into pediatric oncology

Objective: Hypotonic fluids are commonly used in pediatric oncology despite evidence that these fluids can lead to hospital-acquired hyponatremia. This practice is most likely due to lack of data evaluating risks and benefits of isotonic fluids in pediatric oncology. To address this issue, our study investigates the effects of exchanging hypotonic fluids with isotonic fluids in a large pediatric oncology unit. Study Design: Prevalence of laboratory disorders before and after the change to balanced, isotonic fluids for all patients are compared in this retrospective analysis. Disturbances in electrolyte levels, fluid-, acid-base balance and kidney function were examined. Results: The rate of hyponatremia was reduced using isotonic fluids. There were no hypernatremic events. Volume overload might increase the use of furosemide when using isotonic fluids. Potassium and bivalent cation levels increased. The risk of acidosis is greatly reduced, whereas alkalosis was more frequent due to furosemide use. The rate of acute kidney injury did not increase. Conclusion: Using isotonic fluids for hyper-hydration in pediatric oncology lead to a modest reduction of hospital-acquired hyponatremia without causing hypernatremia, but the effects on fluid balance need further investigation. The additional intake of bivalent cations and buffering anions in balanced fluids has measurable effects.

Major adverse kidney events within 30 days in patients with acute pancreatitis: a tertiary-center cohort study

BACKGROUND

To evaluate the event rate of major adverse kidney events within 30 days (MAKE30) in acute pancreatitis (AP) and its potential risk factors.

METHODS

A retrospective analysis of a tertiary center data on all AP patients admitted within 72 h after onset of abdominal pain between June 2015 and June 2019 was conducted. MAKE30 - a composite of death, new renal replacement therapy (RRT), or persistent renal dysfunction (PRD) - and its individual components were retrieved at discharge or 30 days. Logistic regression analysis was used to assess the risk factors for MAKE30.

RESULTS

295 patients were enrolled and 16% experienced MAKE30. For individual components, the incidence was 3% for death, 15% for new RRT, and 5% for PRD. In multivariate logistic regression analysis, hyperchloremia at admission [OR = 8.38 (1.07-65.64); P = 0.043] and SOFA score [OR 1.63 (1.18-2.26); P = 0.003] were independent risk factors in predicting MAKE30. Further analysis showed that patients with hyperchloremia had more requirements of RRT (57% vs. 10%, P < 0.001), more PRD (14% vs. 4%, P = 0.034).

CONCLUSION

MAKE30 is a common event in AP patients. Hyperchloremia and SOFA score at admission were two independent risk factors for MAKE30.

Statistical analysis plan for Better Evidence for Selecting Transplant Fluids (BEST-Fluids): a randomised controlled trial of the effect of intravenous fluid therapy with balanced crystalloid versus saline on the incidence of delayed graft function in deceased donor kidney transplantation

Background

Delayed graft function, or the requirement for dialysis due to poor kidney function, is a frequent complication of deceased donor kidney transplantation that is associated with inferior outcomes. Intravenous fluids with a high chloride content, such as isotonic sodium chloride (0.9% saline), are widely used in transplantation but may increase the risk of poor kidney function. The primary objective of the BEST-Fluids trial is to compare the effect of a balanced low-chloride crystalloid, Plasma-Lyte 148 (Plasmalyte), versus 0.9% saline on the incidence of DGF in deceased donor kidney transplant recipients. This article describes the statistical analysis plan for the trial.

Methods and design

BEST-Fluids is an investigator-initiated, pragmatic, registry-based, multi-centre, double-blind, randomised controlled trial. Eight hundred patients (adults and children) in Australia and New Zealand with end-stage kidney disease admitted for a deceased donor kidney transplant were randomised to intravenous fluid therapy with Plasmalyte or 0.9% saline in a 1:1 ratio using minimization. The primary outcome is delayed graft function (dialysis within seven days post-transplant), which will be modelled using a log-binomial generalised linear mixed model with fixed effects for treatment group, minimization variables, and ischaemic time and a random intercept for study centre. Secondary outcomes including early kidney transplant function (a ranked composite of dialysis duration and the rate of graft function recovery), treatment for hyperkalaemia, and graft survival and will be analysed using a similar modelling approach appropriate for the type of outcome.

Discussion

BEST-Fluids will determine whether Plasmalyte reduces the incidence of DGF and has a beneficial effect on early kidney transplant outcomes relative to 0.9% saline and will inform clinical guidelines on intravenous fluids for deceased donor kidney transplantation. The statistical analysis plan describes the analyses to be undertaken and specified before completion of follow-up and locking the trial databases.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12617000358347. Prospectively registered on 8 March 2017

ClinicalTrials.gov identifier NCT03829488. Registered on 4 February 2019

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05989-w.

Association of hyperchloremia with all-cause mortality in patients admitted to the surgical intensive care unit: a retrospective cohort study

Background

Serum chloride (Cl⁻) is one of the most essential extracellular anions. Based on emerging evidence obtained from patients with kidney or heart disease, hypochloremia has been recognized as an independent predictor of mortality. Nevertheless, excessive Cl⁻ can also cause death in severely ill patients. This study aimed to investigate the relationship between hyperchloremia and high mortality rate in patients admitted to the surgical intensive care unit (SICU).

Methods

We enrolled 2131 patients from the Multiparameter Intelligent Monitoring in Intensive Care III database version 1.4 (MIMIC-III v1.4) from 2001 to 2012. Selected SICU patients were more than 18 years old and survived more than 72 h. A serum Cl⁻ level ≥ 108 mEq/L was defined as hyperchloremia. Clinical and laboratory variables were compared between hyperchloremia (n = 664) at 72 h post-ICU admission and no hyperchloremia (n = 1467). The Locally Weighted Scatterplot Smoothing (Lowess) approach was utilized to investigate the correlation between serum Cl- and the thirty-day mortality rate. The Cox proportional-hazards model was employed to investigate whether serum chlorine at 72 h post-ICU admission was independently related to in-hospital, thirty-day and ninety-day mortality from all causes. Kaplan-Meier curve of thirty-day and ninety-day mortality and serum Cl⁻ at 72 h post-ICU admission was further constructed. Furthermore, we performed subgroup analyses to investigate the relationship between serum Cl⁻ at 72 h post-ICU admission and the thirty-day mortality from all causes.

Results

A J-shaped correlation was observed, indicating that hyperchloremia was linked to an elevated risk of thirty-day mortality from all causes. In the multivariate analyses, it was established that hyperchloremia remained a valuable predictor of in-hospital, thirty-day and ninety-day mortality from all causes; with adjusted hazard ratios (95% CIs) for hyperchloremia of 1.35 (1.02 ~ 1.77), 1.67 (1.28 ~ 2.19), and 1.39 (1.12 ~ 1.73), respectively. In subgroup analysis, we observed hyperchloremia had a significant interaction with AKI (P for interaction: 0.017), but there were no interactions with coronary heart disease, hypertension, and diabetes mellitus (P for interaction: 0.418, 0.157, 0.103, respectively).

Conclusion

Hyperchloremia at 72 h post-ICU admission and increasing serum Cl⁻ were associated with elevated mortality risk from all causes in severely ill SICU patients.

Impact of Comorbidities on Beneficial Effect of Lactated Ringers vs. Saline in Sepsis Patients

Background: Lactated Ringers reduced mortality more than saline in sepsis patients but increased mortality more than saline in traumatic brain injury patients.

Method: This prospective cohort study was conducted in a medical intensive care unit (ICU) in central Taiwan. We applied standard sepsis evaluation protocol and identified heart, lung, liver, kidney, and endocrine comorbidities. We also evaluated resuscitation response with central venous pressure, central venous oxygen saturation, and serum lactate level simultaneously. Propensity-score matching and Cox regression were used to estimate mortality. The competing risk model compared the lengths of hospital stays with the subdistribution hazard ratio (SHR).

Results: Overall, 938 patients were included in the analysis. The lactated Ringers group had a lower mortality rate (adjusted hazard ratio, 0.59; 95% CI 0.43-0.81) and shorter lengths of hospital stay (SHR, 1.39; 95% C.I. 1.15-1.67) than the saline group; the differences were greater in patients with chronic pulmonary disease and small and non-significant in those with chronic kidney disease, moderate to severe liver disease and cerebral vascular disease. The resuscitation efficacy was the same between fluid types, but serum lactate levels were significantly higher in the lactated Ringers group than in the saline group (0.12 mg/dl/h; 95% C.I.: 0.03, 0.21), especially in chronic liver disease patients. Compared to the saline group, the lactated Ringers group achieved target glucose level earlier in both diabetes and non-diabetes patients.

Conclusion: Lactate Ringer's solution provides greater benefits to patients with chronic pulmonary disease than to those with chronic kidney disease, or with moderate to severe liver disease. Comorbidities are important in choosing resuscitation fluid types.

Enhanced recovery after surgery: Current status and future progress

Enhanced Recovery After Surgery (ERAS) pathways were first introduced almost a quarter of a century ago and represent a paradigm shift in perioperative care that reduced postoperative complications and hospital length of stay, improved postoperative quality of life, and reduced overall healthcare costs. Gradual recognition of the generalizability of the interventions and transferable improvements in postoperative outcomes, led them to become standard of care for several surgical procedures. In this article, we critically review the current status of ERAS pathways, address related controversies, and propose measures for future progress.

High Chloride Burden and Clinical Outcomes in Critically Ill Patients With Large Hemispheric Infarction

Background: In general, disease severity has been found to be associated with abnormal chloride levels in critically ill patients, but hyperchloremia is associated with mixed results regarding patient-centered clinical outcomes. We aimed to investigate the impact of maximum serum chloride concentration on the clinical outcomes of critically ill patients with large hemispheric infarction (LHI).

Methods: We conducted a retrospective observational cohort study using prospective institutional neurocritical care registry data from 2013 to 2018. Patients with LHIs involving over two-thirds of middle cerebral artery territory, with or without infarction of other vascular territories, and a baseline National Institutes of Health Stroke Scale score of ≥13 were assessed. Those with a baseline creatinine clearance of <15 mL/min and required neurocritical care for <72 h were excluded. Primary outcome was in-hospital mortality. Secondary outcomes included 3-month mortality and acute kidney injury (AKI) occurrence. Outcomes were compared to different maximum serum chloride levels (5 mmol/L increases) during the entire hospitalization period using multivariable logistic regression analyses.

Results: Of 90 patients, 20 (22.2%) died in-hospital. Patients who died in-hospital had significantly higher maximum serum chloride levels than did those who survived up to hospital discharge (139.7 ± 8.1 vs. 119.1 ± 10.4 mmol/L; p < 0.001). After adjusting for age, sex, and Glasgow coma scale score, each 5-mmol/L increase in maximum serum chloride concentration was independently associated with an increased risk of in-hospital mortality (adjusted odds ratio (aOR), 4.34; 95% confidence interval [CI], 1.98–9.50; p < 0.001). Maximum serum chloride level was also an independent risk factor for 3-month mortality (aOR, 1.99 [per 5 mmol/L increase]; 95% CI, 1.42–2.79; p < 0.001) and AKI occurrence (aOR, 1.57 [per 5 mmol/L increase]; 95% CI, 1.18–2.08; p = 0.002).

Conclusions: High maximum serum chloride concentrations were associated with poor clinical outcomes in critically ill patients with LHI. This study highlights the importance of monitoring serum chloride levels and avoiding hyperchloremia in this patient population.

Presentation of mixed diabetic ketoacidosis and metabolic acidosis due to ileal neobladder reconstruction

Diabetic ketoacidosis (DKA) is one of the most serious acute metabolic complications of diabetes mellitus. It is characterised by the biochemical triad of hyperglycaemia, ketonemia/ketonuria, and an increased anion gap metabolic acidosis. In this case, a 40-year-old male patient presented to the emergency department, with vomiting, nausea, polydipsia, polyuria and weight loss. He was found to have an elevated plasma glucose, despite having no known history of diabetes mellitus. His medical history was significant for spina bifida and ileal neobladder reconstruction. The plasma glucose level was 38 mmol/L. Blood gas analysis showed normal anion gap metabolic acidosis with high chloride and low bicarbonate. His plasma ketone level was 4.5 mmol/L. No significant reason for hyperchloraemia was identified. On initiation of DKA regimen, his condition improved and serum ketones normalised. Due to persistent hyperchloraemic metabolic acidosis, bicarbonate infusion was administered and his metabolic acidosis resolved.

[Therapeutics for acute tubular necrosis in 2020]

Acute kidney injury is a major cause of in-hospital morbidity and mortality because of the serious nature of the underlying illnesses and the high incidence of complications. The two major causes of acute kidney injury that occur in the hospital are prerenal disease and acute tubular necrosis. Acute tubular necrosis has a histological definition, even if a kidney biopsy is rarely performed. Kidney injuries occurring during acute tubular necrosis are underlined by different pathophysiological mechanisms that emphasize the role of hypoxia on the tubular cells such as apoptosis, cytoskeleton disruption, mitochondrial function and the inflammation mediated by innate immune cells. The microcirculation and the endothelial cells are also the targets of hypoxia-mediated impairment. Repair mechanisms are sometimes inadequate because of pro-fibrotic factors that will lead to chronic kidney disease. Despite all the potential therapeutic targets highlighted by the pathophysiological knowledge, further works remain necessary to find a way to prevent these injuries.

A narrative review of acute pancreatitis and its diagnosis, pathogenetic mechanism, and management

Acute pancreatitis (AP) is an inflammatory disease that can progress to severe acute pancreatitis (SAP), which increases the risk of death. AP is characterized by inappropriate activation of trypsinogen, infiltration of inflammatory cells, and destruction of secretory cells. Other contributing factors may include calcium (Ca²⁺) overload, mitochondrial dysfunction, impaired autophagy, and endoplasmic reticulum (ER) stress. In addition, exosomes are also associated with pathophysiological processes of many human diseases and may play a biological role in AP. However, the pathogenic mechanism has not been fully elucidated and needs to be further explored to inform treatment. Recently, the treatment guidelines have changed; minimally invasive therapy is advocated more as the core multidisciplinary participation and "step-up" approach. The surgical procedures have gradually changed from open surgery to minimally invasive surgery that primarily includes percutaneous catheter drainage (PCD), endoscopy, small incision surgery, and video-assisted surgery. The current guidelines for the management of AP have been updated and revised in many aspects. The type of fluid to be used, the timing, volume, and speed of administration for fluid resuscitation has been controversial. In addition, the timing and role of nutritional support and prophylactic antibiotic therapy, as well as the timing of the surgical or endoscopic intervention, and the management of complications still have many uncertainties that could negatively impact the prognosis and patients' quality of life. Consequently, to inform clinicians about optimal treatment, we aimed to review recent advances in the understanding of the pathogenesis of AP and its diagnosis and management.

Impact of a Perioperative Protocol on Length of ICU and Hospital Stay in Complex Spine Surgery

BACKGROUND

In an attempt to improve patient care, a perioperative complex spine surgery management protocol was developed through collaboration between spine surgeons and neuroanesthesiologists. The aim of this study was to investigate whether implementation of the protocol in 2015 decreased total hospital and intensive care unit (ICU) length of stay (LOS) and complication rates after elective complex spine surgery.

MATERIALS AND METHODS

A retrospective cohort study was conducted by review of the medical charts of patients who underwent elective complex spine surgery at an academic medical center between 2012 and 2017. Patients were divided into 2 groups based on the date of their spine surgery in relation to implementation of the spine surgery protocol; before-protocol (January 2012 to March 2015) and protocol (April 2015 to March 2017) groups. Outcomes in the 2 groups were compared, focusing on hospital and ICU LOS, and complication rates.

RESULTS

A total of 201 patients were included in the study; 107 and 94 in the before-protocol and protocol groups, respectively. Mean (SD) hospital LOS was 14.8±10.8 days in the before-protocol group compared with 10±10.7 days in the protocol group (P<0.001). The spine surgery protocol was the primary factor decreasing hospital LOS; incidence rate ratio 0.78 (P<0.001). Similarly, mean ICU LOS was lower in the protocol compared with before-protocol group (4.2±6.3 vs. 6.3±7.3 d, respectively; P=0.011). There were no significant differences in the rate of postoperative complications between the 2 groups (P=0.231).

CONCLUSION

Implementation of a spine protocol reduced ICU and total hospital LOS stay in high-risk spine surgery patients.

Hypertonic saline buffered with sodium acetate for intracranial pressure management

BACKGROUND

3 % hypertonic saline (HS) is a hyperosmolar agent often used to treat elevated intracranial pressure (ICP). However, the resultant hyperchloremia is associated with adverse outcomes in certain patient populations. In this study, HS solution buffered with sodium acetate (HSwSA) is used as an alternative to standard 3 % formulations to reduce overall chloride exposure. Our objectives are to establish whether this alternative agent - with reduced chloride content - is similar to standard 3 % HS in maintaining hyperosmolarity and investigate its effects on hyperchloremia.

METHODS

A retrospective chart review was conducted from August 1, 2014 to August 1, 2017 on patients receiving hypertonic therapies for ICP management. Patients were categorized into three groups, those that received: (1) 3 % HS for at least 72 h, (2) HSwSA for at least 72 h, or (3) were switched from 3 % HS within 72 h of initiating therapy to HSwSA for at least 72 h.

RESULTS

The average increase in serum osmolality after 72 h of therapy was 21.1 moSm/kg for those only on 3 % HS and 20.3 mOsm/kg for those only on HSwSA. Serum chloride levels after 24 h decreased on average by 2.5 mEq/L after switching from 3% HS to HSwSA and stayed below baseline, whereas matched patients only receiving 3% HS on average had serum chloride levels increase 4.3 mEq/L after 24 h and continued to rise.

CONCLUSIONS

Hyperchloremia has been associated with decreased renal perfusion, increasing the risk of acute kidney injury and hyperchloremic metabolic acidosis. Compared to standard 3% HS, our findings suggest an alternative hyperosmolar therapy with less chloride maintains similar hyperosmolarity while reducing overall chloride exposure.

Kidney injury in COVID-19

Coronavirus disease 2019 (COVID-19) continues to affect millions of people around the globe. As data emerge, it is becoming more evident that extrapulmonary organ involvement, particularly the kidneys, highly influence mortality. The incidence of acute kidney injury has been estimated to be 30% in COVID-19 non-survivors. Current evidence suggests four broad mechanisms of renal injury: Hypovolaemia, acute respiratory distress syndrome related, cytokine storm and direct viral invasion as seen on renal autopsy findings. We look to critically assess the epidemiology, pathophysiology and management of kidney injury in COVID-19.

Dyschloremia is associated with failure to restore renal function in survivors with acute kidney injury: an observation retrospective study

Dyschloremia is common in critically ill patients. However, little is known about the effects of dyschloremia on renal function in patients with acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). A total of 483 patients who received CRRT for AKI were selected and divided into three groups according to their serum chloride concentrations at the time of CRRT initiation. At 90 days after initiating CRRT, renal outcome, i.e., non-complete renal recovery, or renal failure, was assessed in the three groups. The hypochloremia group (serum chloride concentrations < 96 mEq/L, n = 60), the normochloremia group (serum chloride concentrations, 96–111 mEq/L, n = 345), and the hyperchloremia group (serum chloride concentrations > 111 mEq/L, n = 78) were classified. The simplified acute physiology score III was higher in the hyperchloremia and hypochloremia groups than in the normochloremia group. Multivariate logistic regression analyses showed that hypochloremia (odds ratio, 5.12; 95% confidence interval [CI], 2.56–10.23; P < 0.001) and hyperchloremia (odds ratio, 2.53; 95% CI, 1.25–5.13; P = 0.01) were significantly associated with non-complete renal recovery. Similar trends were observed for renal failure. This study showed that dyschloremia was independently associated with failure in restoring renal function following AKI.

A randomized, controlled, double-blind crossover study on the effects of isoeffective and isovolumetric intravenous crystalloid and gelatin on blood volume, and renal and cardiac hemodynamics

BACKGROUND & AIMS

Blood volume expanding properties of colloids are superior to crystalloids. In addition to oncotic/osmotic properties, the electrolyte composition of infusions may have important effects on visceral perfusion, with infusions containing supraphysiological chloride causing hyperchloremic acidosis and decreased renal blood flow. In this non-inferiority study, a validated healthy human subject model was used to compare effects of colloid (4% succinylated gelatin) and crystalloid fluid regimens on blood volume, renal function, and cardiac output.

METHODS

Healthy male participants were given infusions over 60 min > 7 days apart in a randomized, crossover manner. Reference arm (A): 1.5 L of Sterofundin ISO, isoeffective arm (B): 0.5 L of 4% Gelaspan®, isovolumetric arm (C): 0.5 L of 4% Gelaspan® and 1 L of Sterofundin ISO (all B. Braun, Melsungen, Germany). Participants were studied over 240 min. Changes in blood volume were calculated from changes in weight and hematocrit. Renal volume, renal artery blood flow (RABF), renal cortex perfusion and diffusion, and cardiac index were measured with magnetic resonance imaging.

RESULTS

Ten of 12 males [mean (SE) age 23.9 (0.8) years] recruited, completed the study. Increase in body weight and extracellular fluid volume were significantly less after infusion B than infusions A and C, but changes in blood volume did not significantly differ between infusions. All infusions increased renal volume, with no significant differences between infusions. There was no significant difference in RABF across the infusion time course or between infusion types. Renal cortex perfusion decreased during the infusion (mean 18% decrease from baseline), with no significant difference between infusions. There was a trend for increased renal cortex diffusion (4.2% increase from baseline) for the crystalloid infusion. All infusions led to significant increases in cardiac index.

CONCLUSIONS

A smaller volume of colloid (4% succinylated gelatin) was as effective as a larger volume of crystalloid at expanding blood volume, increasing cardiac output and changing renal function. Significantly less interstitial space expansion occurred with the colloid.

TRIAL REGISTRATION

The protocol was registered with the European Union Drug Regulating Authorities Clinical Trials Database (https://eudract.ema.europa.eu) (EudraCT No. 2013-003260-32).

Study Protocol for Better Evidence for Selecting Transplant Fluids (BEST-Fluids): a pragmatic, registry-based, multi-center, double-blind, randomized controlled trial evaluating the effect of intravenous fluid therapy with Plasma-Lyte 148 versus 0.9% saline on delayed graft function in deceased donor kidney transplantation

Background

Delayed graft function, the requirement for dialysis due to poor kidney function post-transplant, is a frequent complication of deceased donor kidney transplantation and is associated with inferior outcomes and higher costs. Intravenous fluids given during and after transplantation may affect the risk of poor kidney function after transplant. The most commonly used fluid, isotonic sodium chloride (0.9% saline), contains a high chloride concentration, which may be associated with acute kidney injury, and could increase the risk of delayed graft function. Whether using a balanced, low-chloride fluid instead of 0.9% saline is safe and improves kidney function after deceased donor kidney transplantation is unknown.

Methods

BEST-Fluids is an investigator-initiated, pragmatic, registry-based, multi-center, double-blind, randomized controlled trial. The primary objective is to compare the effect of intravenous Plasma-Lyte 148 (Plasmalyte), a balanced, low-chloride solution, with the effect of 0.9% saline on the incidence of delayed graft function in deceased donor kidney transplant recipients. From January 2018 onwards, 800 participants admitted for deceased donor kidney transplantation will be recruited over 3 years in Australia and New Zealand. Participants are randomized 1:1 to either intravenous Plasmalyte or 0.9% saline peri-operatively and until 48 h post-transplant, or until fluid is no longer required; whichever comes first. Follow up is for 1 year. The primary outcome is the incidence of delayed graft function, defined as dialysis in the first 7 days post-transplant. Secondary outcomes include early kidney transplant function (composite of dialysis duration and rate of improvement in graft function when dialysis is not required), hyperkalemia, mortality, graft survival, graft function, quality of life, healthcare resource use, and cost-effectiveness. Participants are enrolled, randomized, and followed up using the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry.

Discussion

If using Plasmalyte instead of 0.9% saline is effective at reducing delayed graft function and improves other clinical outcomes in deceased donor kidney transplantation, this simple, inexpensive change to using a balanced low-chloride intravenous fluid at the time of transplantation could be easily implemented in the vast majority of transplant settings worldwide.

Trial registration

Australian New Zealand Clinical Trials Registry: ACTRN12617000358347. Registered on 8 March 2017. ClinicalTrials.gov: NCT03829488. Registered on 4 February 2019.

Intravenous fluid therapy in the perioperative and critical care setting: Executive summary of the International Fluid Academy (IFA)

Intravenous fluid administration should be considered as any other pharmacological prescription. There are three main indications: resuscitation, replacement, and maintenance. Moreover, the impact of fluid administration as drug diluent or to preserve catheter patency, i.e., fluid creep, should also be considered. As for antibiotics, intravenous fluid administration should follow the four Ds: drug, dosing, duration, de-escalation. Among crystalloids, balanced solutions limit acid–base alterations and chloride load and should be preferred, as this likely prevents renal dysfunction. Among colloids, albumin, the only available natural colloid, may have beneficial effects. The last decade has seen growing interest in the potential harms related to fluid overloading. In the perioperative setting, appropriate fluid management that maintains adequate organ perfusion while limiting fluid administration should represent the standard of care. Protocols including a restrictive continuous fluid administration alongside bolus administration to achieve hemodynamic targets have been proposed. A similar approach should be considered also for critically ill patients, in whom increased endothelial permeability makes this strategy more relevant. Active de-escalation protocols may be necessary in a later phase. The R.O.S.E. conceptual model (Resuscitation, Optimization, Stabilization, Evacuation) summarizes accurately a dynamic approach to fluid therapy, maximizing benefits and minimizing harms. Even in specific categories of critically ill patients, i.e., with trauma or burns, fluid therapy should be carefully applied, considering the importance of their specific aims; maintaining peripheral oxygen delivery, while avoiding the consequences of fluid overload.

Managing Chloride and Bicarbonate in the Prevention and Treatment of Acute Kidney Injury

Intravenous crystalloid therapy is one of the most ubiquitous aspects of hospital and critical care medicine. In recent years, there has been increasing focus on the electrolyte composition, and particularly chloride content, of crystalloid solutions. This has led to increasing clinical adoption of balanced solutions, containing substrates for bicarbonate generation and consequently a lower chloride content, in place of 0.9% saline. In this article we review the physiochemical rationale for avoidance of 0.9% saline and the effects of hyperchloremic acidosis on renal physiology. Finally, we review the current evidence and rationale for use of balanced solutions greater than 0.9% saline in acutely ill patients in a variety of clinical settings, as well as considering the role for sodium bicarbonate in preventing or correcting metabolic acidosis. In conclusion, there is a strong physiological rationale for avoidance of iatrogenic hyperchloremic acidosis from 0.9% saline administration in acutely unwell patients and an association with adverse renal outcomes in several studies. However, evidence from large definitive multicenter randomized trials is not yet available to establish the dose-relationship between 0.9% saline administration and potential harm and inform us if some 0.9% saline use is acceptable or if any exposure confers harm.

High-anion gap hyperchloremic acidosis mimicking diabetic ketoacidosis on initial presentation - Case report

INTRODUCTION

Diabetic ketoacidosis (DKA) often becomes the primary focus and in turn masks a similar serious condition like hyperchloremic metabolic acidosis.

CASE REPORT

A 20 years old female with type 1 diabetes mellitus presented to the emergency department (ED) with signs and symptoms corresponding to DKA. Initial pH, HCO_3, Na and Cl concentrations were 6.83, 3.6 mmol/l, 143 mmol/l and 122 mmol/l respectively; anion gap 17.4 mmol/l and absent urinary ketones. DKA regime showed no improvement in the measured parameters nor the patient. The diagnosis changed to hyperchloremic high-anion gap acidosis and treatment modifications were made by adding sodium bicarbonate infusion. There was significant improvement in the clinical status of the patient and the calculated parameters.

DISCUSSION

Hyperchloremic acidosis is associated with a non-anion gap, decrease in plasma bicarbonate and increase in plasma chloride. Rarely, as with this case, it may present with a high-anion gap. The use of bicarbonate therapy has shown improvement in cases of non-anion gap acidosis however there is very little data to support its role in high-anion gap hyperchloremic metabolic acidosis.

Fluid Therapy in Patients Undergoing Abdominal Surgery: A Bumpy Road Towards Individualized Management

Prudent intraoperative fluid replacement therapy, inotropes, and vasoactive drugs should be guided by adequate hemodynamic monitoring. The study aimed to evaluate the single-centre practice on intraoperative fluid therapy in abdominal surgery (AS). The evaluation, based on a review of medical files, included 235 patients (103 men), aged 60 ± 15 years who underwent AS between September and November 2017. Fluid therapy was analyzed in terms of quality and quantity. There were 124 high-risk patients according to the American Society of Anaesthesiologists Classification (ASA Class 3+) and 89 high-risk procedures performed. The median duration of procedures was 175 (IQR 106-284) min. Eleven patients died post-operatively. The median fluids volume was 10.4 mL/kg/h of anaesthesia, including 9.1 mL/kg/h of crystalloids and 2.7 mL/kg/h of synthetic colloids. Patients undergoing longer than the median procedures received significantly fewer fluids than those who underwent shorter procedures. The volume of fluids in the longer procedures depended on the procedural risk classification and was significantly greater in high-risk patients undergoing high-risk surgery. Patients who died received significantly more fluids than survivors. In all patients, a non-invasive blood pressure monitoring was used and only six patients had therapy guided by metabolic equilibrium. The fluid therapy used was liberal but complied with the recommendations regarding the type of fluid and risk-adjusted dosing. Hemodynamic monitoring was suboptimal and requires modifications. In conclusion, the optimization of intraoperative fluid therapy requires a balanced and standardized approach consistent with treatment procedures.

Perioperative renal protection

PURPOSE OF REVIEW

The present article reviews the recent literature on the main aspects of perioperative acute kidney injury (AKI).

RECENT FINDINGS

AKI occurs in 1 in every 10 surgical patients, with cardiac, orthopedic, and major abdominal surgeries being the procedures associated with the highest risk. Overall, complex operations, bleeding, and hemodynamic instability are the most consistent procedure-related risk factors for AKI. AKI increases hospital stay, mortality, and chronic kidney disease, gradually with severity. Furthermore, delayed renal recovery negatively impacts on patients' outcomes. Cell cycle arrest biomarkers seem promising to identify high-risk patients who may benefit from the bundles recommended by the Kidney Disease: Improving Global Outcomes guidelines. Hemodynamic management using protocol-based administration of fluids and vasopressors helps reducing AKI. Recent studies have highlighted the benefit of personalizing the blood pressure target according to the patient's resting reference, and avoiding both hypovolemia and fluid overload. Preliminary research has reported encouraging renoprotective effects of angiotensin II and nitric oxide, which need to be confirmed. Moreover, urinary oxygenation monitoring appears feasible and a fair predictor of postoperative AKI.

SUMMARY

AKI remains a frequent and severe postoperative complication. A personalizedmulticomponent approach might help reducing the risk of AKI and improving patients' outcomes.

Fluid Stewardship During Critical Illness: A Call to Action

Intravenous fluids (IVFs) are the most common drugs administered in the intensive care unit. Despite the ubiquitous use, IVFs are not benign and carry significant risks associated with under- or overadministration. Hypovolemia is associated with decreased organ perfusion, ischemia, and multi-organ failure. Hypervolemia and volume overload are associated with organ dysfunction, delayed liberation from mechanical ventilation, and increased mortality. Despite appropriate provision of IVF, adverse drug effects such as electrolyte abnormalities and acid-base disturbances may occur. The management of volume status in critically ill patients is both dynamic and tenuous, a process that requires frequent monitoring and high clinical acumen. Because patient-specific considerations for fluid therapy evolve across the continuum of critical illness, a standard approach to the assessment of fluid needs and prescription of IVF therapy is necessary. We propose the principle of "fluid stewardship," guided by 4 rights of medication safety: right patient, right drug, right route, and right dose. The successful implementation of fluid stewardship will aid pharmacists in making decisions regarding IVF therapy to optimize hemodynamic management and improve patient outcomes. Additionally, we highlight several areas of focus for future research, guided by the 4 rights construct of fluid stewardship.

Hyperchloremia in Intensive Care Unit Mortality: An Underestimated Fact

Objective

The goal of the study was to determine the percentage of hyperchloremia in patients who died in medical intensive care unit (ICU) and thus emphasizing the need of avoiding chloride-rich solutions due to their deleterious effects.

Study design

We conducted a retrospective study of data from 206 patients who expired in medical ICU in one year from January 2017 to December 2017 in the department of critical care medicine at Shifa International Hospital, Islamabad.

Material and methods

The study included 206 patients: 93 (43.1%) men and 123 (56.9%) women, over the age of 18 years who expired in medical ICU in one year from January 2017 to December 2017. Patients included for the study were all those who expired with any diagnosis but those who remained admitted in ICU for at least 72 hours and received intravenous fluids. The serum chloride levels of the patients at the time of admission and at 72 hours of stay in ICU were collected. The patients who were having serum chloride levels of 107 milliequivalent per deciliter (meq/dl) or more were labeled as having hyperchloremia. The data were analyzed using IBM SPSS Statistics for Windows, Version 23.0 (IBM Crop., Armonk, NY, USA). The mean and standard deviations were calculated for continuous variables while frequency and percentages were calculated for qualitative variables.

Results

Among 206 patients who expired in our ICU, 109 (50.5%) patients had hyperchloremia at 72 hours of admission in ICU while 107 (49.5%) patients did not had hyperchloremia. Hyperchloremia was more frequent in patients with sepsis or septic shock.

Conclusion

Higher percentage (50.5%) of hyperchloremia at 72 hours of admission among patients (who expired in our medical ICU) indicates excessive use of chloride-rich intravenous fluids. This finding may have significant impact on mortality along with other contributing factors that lead to death of the patients. Keeping in view the findings of the study, chloride-rich solutions should be used carefully to counter the effects of hyperchloremia in patients requiring large volume fluid resuscitation in ICU. Fluids with lower content of chloride such as lactated ringer may be equally good in large volume fluid resuscitation with advantage of avoiding hyperchloremia.

A prospective, randomized, comparison study on effect of perioperative use of chloride liberal intravenous fluids versus chloride restricted intravenous fluids on postoperative acute kidney injury in patients undergoing off-pump coronary artery bypass grafting surgeries

Context and Aims:

Off-pump coronary artery bypass graft (OPCABG) is a form of CABG surgery. It is performed without the use of cardiopulmonary bypass machine as a surgical treatment for coronary heart disease. Acute kidney injury (AKI) is one of the common postoperative complications of OPCABG. Previous studies suggest important differences related to intravenous fluid (IVF) chloride content and renal function. We hypothesize that perioperative use of chloride restricted IVFs may decrease incidence and severity of postoperative AKI in patients undergoing OPCABG.

Methods:

Six hundred patients were randomly divided into two groups of 300 each. In Group A (n = 300), chloride liberal IVFs, namely, hydroxyethyl starch (130/0.4) in 0.9% normal saline (Voluven), 0.9% normal saline, and Ringer's lactate were used for perioperative fluid management. In Group B (n = 300), chloride-restricted IVFs, namely, hydroxyethyl starch (130/0.4) in balanced colloid solution (Volulyte) and balanced salt crystalloid solution (PlasmaLyte A), were used for perioperative fluid management. Serum creatinine values were taken preoperatively, postoperatively at 24 h and at 48 h. Postoperative AKI was determined by AKI network (AKIN) criteria.

Results:

In Group A, 9.2% patients and in Group B 4.6% patients developed Stage-I AKI determined by AKIN criteria which was statistically significant (P < 0.05).

Conclusion:

Perioperative use of chloride restricted IVF was found to decrease incidence of postoperative AKI. The use of chloride liberal IVF was associated with hyperchloremic metabolic acidosis.

Guidelines for Perioperative Care in Elective Colorectal Surgery: Enhanced Recovery After Surgery (ERAS®) Society Recommendations: 2018

BACKGROUND

This is the fourth updated Enhanced Recovery After Surgery (ERAS®) Society guideline presenting a consensus for optimal perioperative care in colorectal surgery and providing graded recommendations for each ERAS item within the ERAS® protocol.

METHODS

A wide database search on English literature publications was performed. Studies on each item within the protocol were selected with particular attention paid to meta-analyses, randomised controlled trials and large prospective cohorts and examined, reviewed and graded according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

RESULTS

All recommendations on ERAS® protocol items are based on best available evidence; good-quality trials; meta-analyses of good-quality trials; or large cohort studies. The level of evidence for the use of each item is presented accordingly.

CONCLUSIONS

The evidence base and recommendation for items within the multimodal perioperative care pathway are presented by the ERAS® Society in this comprehensive consensus review.

Effects of chloride content of intravenous crystalloid solutions in critically ill adult patients: a meta-analysis with trial sequential analysis of randomized trials

BACKGROUND

Intravenous crystalloid solutions are administered commonly for critically ill patients. We performed this meta-analysis of randomized trials with trial sequential analysis (TSA) to evaluate effects of chloride content of intravenous crystalloid solutions on clinical outcomes among critically ill adult patients.

METHODS

Electronic databases were searched up to June 1, 2018, for randomized trials of use of balanced crystalloids versus 0.9% saline solutions in critically ill adult patients. The outcome variables included mortality, renal outcomes, serum content alterations and organ function. Subgroup analysis was conducted according to patient settings, types or volume of crystalloid fluid, or among sepsis versus non-sepsis, TBI versus non-TBI or subpopulations by the categories of baseline kidney function. Random errors were evaluated by trial sequential analysis.

RESULTS

Eight studies with 19,301 patients were analyzed. A trend of in-hospital survival benefit with no statistical difference could be observed with balanced crystalloids compared with 0.9% saline (RR 0.92, 95% CI 0.85-1.0, p = 0.06). The use of balanced crystalloid solutions was associated with longer RRT-free days (SMD 0.09, 95% CI 0.06-0.12, p < 0.001), less risk of increase in serum concentrations of chloride (SMD - 1.23, 95% CI - 1.59 to - 0.87, p < 0.001) and sodium (SMD - 1.28, 95% CI - 1.65 to - 0.92, p < 0.001), less risk of decline in serum base deficit (SMD - 0.58, 95% CI - 0.98 to - 0.18, p = 0.004), longer ventilator-free days (SMD 0.08, 95% CI 0.05-0.11, p < 0.001) and vasopressor-free days (SMD 0.04, 95% CI 0.00-0.07, p = 0.02). Subgroup analysis showed that balanced crystalloid solutions were associated with a reduced in-hospital mortality rate among septic patients (RR 0.86, 95% CI 0.75-0.98; p = 0.02) and non-traumatic brain injury patients (RR 0.90, 95% CI 0.82-0.99, p = 0.02), while the TSA results indicated a larger sample size is still in need.

CONCLUSIONS

Limited evidence supported statistical survival benefit with balanced crystalloid solutions, while it benefited in reducing organ support duration and fluctuations in serum electrolyte and base excess and was associated with decreased in-hospital mortality in subpopulation with sepsis and non-TBI. Large-scale rigorous randomized trials with better designs are needed to provide robust evidence for clinical management. Trial registration The protocol for this meta-analysis was registered on PROSPERO: International prospective register of systematic reviews (CRD42018102661), https://www.crd.york.ac.uk/prospero/#recordDetails.

"I don't get no respect": the role of chloride in acute kidney injury

Acute kidney injury (AKI) is a major public health problem that complicates 10-40% of hospital admissions. Importantly, AKI is independently associated with increased risk of progression to chronic kidney disease, end-stage renal disease, cardiovascular events, and increased risk of in-hospital and long-term mortality. The chloride content of intravenous fluid has garnered much attention over the last decade, as well as its association with excess use and adverse outcomes, including AKI. Numerous studies show that changes in serum chloride concentration, independent of serum sodium and bicarbonate, are associated with increased risk of AKI, morbidity, and mortality. This comprehensive review details the complex renal physiology regarding the role of chloride in regulating renal blood flow, glomerular filtration rate, tubuloglomerular feedback, and tubular injury, as well as the findings of clinical research related to the chloride content of intravenous fluids, changes in serum chloride concentration, and AKI. Chloride is underappreciated in both physiology and pathophysiology. Although the exact mechanism is debated, avoidance of excessive chloride administration is a reasonable treatment option for all patients and especially in those at risk for AKI. Therefore, high-risk patients and those with "incipient" AKI should receive balanced solutions rather than normal saline to minimize the risk of AKI.

Effect of isotonic versus hypotonic maintenance fluid therapy on urine output, fluid balance, and electrolyte homeostasis: a crossover study in fasting adult volunteers

Background. Daily and globally, millions of adult hospitalized patients are exposed to maintenance i.v. fluid solutions supported by limited scientific evidence. In particular, it remains unclear whether fluid tonicity contributes to the recently established detrimental effects of fluid, sodium, and chloride overload.

Methods. This crossover study consisted of two 48 h study periods, during which 12 fasting healthy adults were treated with a frequently prescribed solution (NaCl 0.9% in glucose 5% supplemented by 40 mmol litre⁻¹ of potassium chloride) and a premixed hypotonic fluid (NaCl 0.32% in glucose 5% containing 26 mmol litre⁻¹ of potassium) at a daily rate of 25 ml kg⁻¹ of body weight. The primary end point was cumulative urine volume; fluid balance was thus calculated. We also explored the physiological mechanisms behind our findings and assessed electrolyte concentrations.

Results. After 48 h, 595 ml (95% CI: 454–735) less urine was voided with isotonic fluids than hypotonic fluids (P<0.001), or 803 ml (95% CI: 692–915) after excluding an outlier with ‘exaggerated natriuresis of hypertension’. The isotonic treatment was characterized by a significant decrease in aldosterone (P<0.001). Sodium concentrations were higher in the isotonic arm (P<0.001), but all measurements remained within the normal range. Potassium concentrations did not differ between the two solutions (P=0.45). Chloride concentrations were higher with the isotonic treatment (P<0.001), even causing hyperchloraemia.

Conclusions. Even at maintenance rate, isotonic solutions caused lower urine output, characterized by decreased aldosterone concentrations indicating (unintentional) volume expansion, than hypotonic solutions and were associated with hyperchloraemia. Despite their lower sodium and potassium content, hypotonic fluids were not associated with hyponatraemia or hypokalaemia.

Clinical trial registration. ClinicalTrials.gov (NCT02822898) and EudraCT (2016-001846-24).

Impact of Isolyte Versus 0.9% Saline on Postoperative Event of Acute Kidney Injury Assayed by Urinary [TIMP-2] × [IGFBP7] in Patients Undergoing Cardiac Surgery

OBJECTIVE

Administration of excess chloride in 0.9% normal saline (NS) decreases renal perfusion and glomerular filtration rate, thereby increasing the risk for acute kidney injury (AKI). In this study, the effect of NS versus Isolyte use during cardiac surgery on urinary levels of tissue inhibitor of metalloproteinase 2 and insulin-like growth factor-binding protein 7 [TIMP-2] × [IGFBP7] and postoperative risk of AKI were examined.

DESIGN

Prospective, randomized, and single-blinded trial.

SETTING

Single university medical center.

PARTICIPANTS

Thirty patients over 18 years without chronic renal insufficiency or recent AKI undergoing elective cardiac surgery.

INTERVENTIONS

Subjects were randomized to receive either NS or Isolyte during the intraoperative period.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the change in urinary levels of [TIMP2] × [IGFBP7] from before surgery to 24 hours postoperatively. Secondary outcomes included serum creatinine pre- and postoperatively at 24 and 48 hours, serum chloride pre- and postoperatively at 24 and 48 hours, need for dialysis prior to discharge, and arterial pH measured 24 hours postoperatively. Sixteen patients received NS and 14 patients received Isolyte. Three patients developed AKI within the first 3 postoperative days, all in the NS group. The authors found increases in [TIMP-2] × [IGFBP7] in both groups. However, the difference in this increase between study arms was not significant (p = 0.92; -0.097 to 0.107).

CONCLUSION

The authors observed no change in urinary [TIMP-] × [IGFBP7] levels in patients receiving NS versus Isolyte during cardiac surgery. Future larger studies in patients at higher risk for AKI are recommended to evaluate the impact of high- versus lower-chloride solutions on the risk of postoperative AKI after cardiac surgery.

Hyperchloremia Is Associated With Poorer Outcome in Critically Ill Stroke Patients

Background and Purpose: This study aims to explore the cause and predictive value of hyperchloremia in critically ill stroke patients.

Materials and Methods: We conducted a retrospective study of a prospectively collected database of adult patients with first-ever acute ischemic stroke (AIS) or intracerebral hemorrhage (ICH) admitted to the neurointensive care unit (NICU) of a university-affiliated hospital, between January 2013 and December 2016. Patients were excluded if admitted beyond 72 h from onset, if they required neurocritical care for less than 72 h, and were treated with hypertonic saline within 72 h or had creatinine clearance less than 15 mL/min.

Results: Of 405 eligible patients, the prevalence of hyperchloremia ([Cl⁻] ≥ 110 mmol/L) was 8.6% at NICU admission ([Cl⁻]₀) and 17.0% within 72 h ([Cl⁻]_max). Thirty-eight (9.4%) patients had new-onset hyperchloremia and 110 (27.1%) had moderate increase in chloride (Δ[Cl⁻] ≥ 5 mmol/L; Δ[Cl⁻] = [Cl⁻]_max − [Cl⁻]₀) in the first 72 h after admission, which were found to be determined by the sequential organ failure assessment score in multivariate logistic regression analysis. Neither total fluid input nor cumulative fluid balance had significant association with such chloride disturbance. New-onset hyperchloremia and every 5 mmol/L increment in Δ[Cl⁻] were both associated with increased odds of 30-day mortality and 6-month poor outcome, although no independent significance was found in multivariate models.

Conclusion: Hyperchloremia tends to occur in patients more severely affected by AIS and ICH. Although no independent association was found, new-onset hyperchloremia and every 5 mmol/L increment in Δ[Cl⁻] were related to poorer outcome in critically ill AIS and ICH patients.

Subject terms: clinical studies, intracranial hemorrhage, ischemic stroke, mortality/survival, quality and outcomes.

Update on perioperative acute kidney injury

PURPOSE OF REVIEW

In this review, we discuss the latest updates on perioperative acute kidney injury (AKI) and the specific considerations that are relevant to different surgeries and patient populations.

RECENT FINDINGS

AKI diagnosis is constantly evolving. New biomarkers detect AKI early and shed a light on the possible cause of AKI. Hypotension, even for a short duration, is associated with perioperative AKI. The debate on the deleterious effects of chloride-rich solutions is still far from conclusion. Remote ischemic preconditioning is showing promising results in the possible prevention of perioperative AKI. No definite data show a beneficiary effect of statins, fenoldepam, or sodium bicarbonate in preventing AKI.

SUMMARY

Perioperative AKI is prevalent and associated with significant morbidity and mortality. Considering the lack of effective preventive or therapeutic interventions, this review focuses on perioperative AKI: measures for early diagnosis, defining risks and possible mechanisms, and summarizing current knowledge for intraoperative fluid and hemodynamic management to reduce risk of AKI.

Attributable Risk and Time Course of Colistin-Associated Acute Kidney Injury

BACKGROUND AND OBJECTIVES

Despite colistin's longstanding reported association with nephrotoxicity, the attributable risk and timing of toxicity onset are still unknown. Whether substantial toxicity occurs during the initial 72 hours of exposure has important implications for early treatment decisions. The objective of this study was to compare colistin-exposed patients with a matched control group given other broad spectrum antibiotics.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective cohort study in patients treated for multidrug-resistant Pseudomonas, Klebsiella, or Acinetobacter spp. Colistin-exposed patients were matched to unexposed controls using propensity scores. AKI was defined according to the Kidney Disease Improving Global Outcomes creatinine criteria. Incidence rate ratios and risk differences of AKI in the matched cohort were estimated with the generalized estimating equation Poisson regression model. Risk factors for AKI were tested for effect modification in the matched cohort.

RESULTS

The study included 150 propensity-matched pairs with similar types of infection, similar delays to effective treatment, and similar baseline characteristics. Incidence of AKI was 77 of 150 (51%) in the colistin group versus 33 of 150 (22%) in matched controls (risk difference, 29%; 95% confidence interval, 19 to 39), corresponding to a number needed to harm of 3.5. Early toxicity was apparent, because AKI risk was higher in colistin-exposed patients at 72 hours of exposure (incidence rate ratio, 1.9; 95% confidence interval, 1.1 to 3.5). In both groups, hospital mortality in patients who experienced AKI was lower if kidney function returned to baseline during hospitalization. The effect of colistin exposure on AKI risk varied inversely according to baseline hemoglobin concentration.

CONCLUSIONS

Colistin is associated with substantial excess AKI that is apparent within the first 72 hours of treatment. Colistin's toxicity varied according to baseline hemoglobin concentration.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_03_15_CJASNPodcast_18_4_M.mp3.