Balanced Crystalloids versus Saline in Critically Ill Adults with Hyperkalemia or Acute Kidney Injury: Secondary Analysis of a Clinical Trial

Balanced Electrolyte Solutions Versus 0.9% Saline for Kidney Transplantation: An Updated Systematic Review and Meta-analysis

Background

Perioperative intravenous fluids are administered to kidney transplant recipients to maintain hemodynamic stability and graft perfusion; however, the ideal fluid remains uncertain. Although 0.9% saline (saline) is commonly used, its high chloride content causes hyperchloremic metabolic acidosis and may increase the risks of delayed graft function (DGF) and hyperkalemia. Balanced electrolyte solutions (BES) have a more physiological chloride concentration and may reduce these risks. Previous meta-analyses found insufficient evidence to compare BES with saline for these outcomes; however, new studies have recently been published. In this updated review, we compared the effects of BES with saline on the risk of DGF and hyperkalemia in kidney transplantation.

Methods

MEDLINE, Embase, and CENTRAL were searched for randomized controlled trials comparing BES with saline in kidney transplantation. The primary outcomes were DGF and hyperkalemia. Eligible studies were assessed for risk of bias and data were pooled for analysis. The Grading of Recommendations Assessment, Development, and Evaluation framework was used to assess the quality of evidence.

Results

Ten studies involving 1532 participants were included. The quality of evidence was high for deceased donor transplantation and very low for living donor transplantation. The relative risk (RR) of DGF associated with BES compared with saline was 0.83 (95% confidence interval [CI], 0.71-0.96; P = 0.01) in deceased donor transplantation. There was no difference in DGF in living donor transplantation (RR 0.79; 95% CI, 0.26-2.41; P = 0.68). There was no difference in hyperkalemia between groups (RR 0.87; 95% CI, 0.59-1.27; P = 0.46).

Conclusions

Compared with saline, BES reduces the risk of DGF in deceased donor kidney transplantation without increasing hyperkalemia.

Fluid management of acute kidney injury

PURPOSE OF REVIEW

Acute kidney injury (AKI) is commonly encountered in critical care medicine as is intravenous fluid therapy. It is accepted that there is interplay between fluid use and AKI, both potentially positive and negative. An understanding of the physiological rationale for fluid is important to help clinicians when considering fluid therapy in patients with, or at risk for AKI; this includes understanding choice of fluid, method of monitoring, administration and clinical sequelae.

RECENT FINDINGS

There is increasing interest in combining both static and dynamic measures to assess fluid balance, fluid responsiveness effects of fluid therapy, which are areas requiring ongoing study to translate this theory into clinically useful practice at the bedside. Whilst the debate of choice of crystalloid in ICU practice continues, further evidence for benefits for balanced solutions emerges in the form of international guidelines and patient data meta-analysis of previously performed trials.

SUMMARY

This review assesses the physiological rationale for fluid use in ICU cohorts with AKI of various types, as well as a systematic approach for choice of fluid therapy using a number of different variables, which aims to help guide clinicians in managing fluid use and fluid balance in critically ill patients with AKI.

Use of fluid therapy in perioperative adult patients: A narrative review

The administration of intravenous fluids is the most common intervention in hospitalised patients in the perioperative setting and critical care units. The aim of this narrative review is to provide an overview of balanced solutions for fluid therapy in the perioperative period in adult patients, and to review new trends and solutions in fluid therapy. The evidence was grouped into 3 areas: intraoperative fluid administration, fluid administration in critically ill patients, and the importance / benefit of balanced crystalloid solutions. Although a number of high-quality studies have been published in recent years, the scientific evidence regarding the type of fluid, the dose, and rate of administration is still limited. The choice of fluid therapy during the perioperative period must be tailored to patient-specific factors, the nature of the surgery, expected fluid loss, and other relevant factors. Finally, more robust clinical evidence and physician training is of the utmost importance.

Current Thoughts on Burn Resuscitation

The optimal treatment of burn shock is still unresolved. The problem of "fluid creep" continues despite modern devices that fail to improve outcomes over hourly urine output. Colloids, especially albumin, reduce fluid requirements. Albumin can be used either immediately at the start of resuscitation, or as a "rescue" when crystalloid use is excessive. Several studies confirm that when crystalloid resuscitation is "out of control" the majority of caregivers will add albumin to reduce fluid rates. A multi-center trial is underway comparing crystalloids with albumin to confirm the benefit of colloids. The next question is whether albumin or plasma is as the better colloid choice.

Sepsis-associated acute kidney injury: recent advances in enrichment strategies, sub-phenotyping and clinical trials

Acute kidney injury (AKI) often complicates sepsis and is associated with high morbidity and mortality. In recent years, several important clinical trials have improved our understanding of sepsis-associated AKI (SA-AKI) and impacted clinical care. Advances in sub-phenotyping of sepsis and AKI and clinical trial design offer unprecedented opportunities to fill gaps in knowledge and generate better evidence for improving the outcome of critically ill patients with SA-AKI. In this manuscript, we review the recent literature of clinical trials in sepsis with focus on studies that explore SA-AKI as a primary or secondary outcome. We discuss lessons learned and potential opportunities to improve the design of clinical trials and generate actionable evidence in future research. We specifically discuss the role of enrichment strategies to target populations that are most likely to derive benefit and the importance of patient-centered clinical trial endpoints and appropriate trial designs with the aim to provide guidance in designing future trials.

Acute kidney injury in patients with burns

Burn injury is associated with a high risk of acute kidney injury (AKI) with a prevalence of AKI among patients with burns of 9-50%. Despite an improvement in burn injury survival in the past decade, AKI in patients with burns is associated with an extremely poor short-term and long-term prognosis, with a mortality of >80% among those with severe AKI. Factors that contribute to the development of AKI in patients with burns include haemodynamic alterations, burn-induced systemic inflammation and apoptosis, haemolysis, rhabdomyolysis, smoke inhalation injury, drug nephrotoxicity and sepsis. Early and late AKI after burn injury differ in their aetiologies and outcomes. Sepsis is the main driver of late AKI in patients with burns and late AKI has been associated with higher mortality than early AKI. Prevention of early AKI involves correction of hypovolaemia and avoidance of nephrotoxic drugs (for example, hydroxocobalamin), whereas prevention of late AKI involves prevention and early recognition of sepsis as well as avoidance of nephrotoxins. Treatment of AKI in patients with burns remains supportive, including prevention of fluid overload, treatment of electrolyte disturbance and use of kidney replacement therapy when indicated.

Precision fluid and vasoactive drug therapy for critically ill patients

There are several clinical practice guidelines concerning the use of fluid and vasoactive drug therapies in critically ill adult patients, but the recommendations in these guidelines are often based on low-quality evidence. Further, some were compiled prior to the publication of landmark clinical trials, particularly in the comparison of balanced crystalloid and normal saline. An important consideration in the treatment of critically ill patients is the application of precision medicine to provide the most effective care to groups of patients most likely to benefit from the therapy. Although not currently widely integrated into these practice guidelines, the utility of precision medicine in critical illness is a recognized research priority for fluid and vasoactive therapy management. The purpose of this narrative review was to illustrate the evaluation and challenges of providing precision fluid and vasoactive therapies to adult critically ill patients. The review includes a discussion of important investigations published after the release of currently available clinical practice guidelines to provide insight into how recommendations and research priorities may change future guidelines and bedside care for critically ill patients.

Sepsis Management in the Cardiac Intensive Care Unit

Septic shock management in the cardiac intensive care unit (CICU) is challenging due to the complex interaction of pathophysiology between vasodilatory and cardiogenic shock, complicating how to optimally deploy fluid resuscitation, vasopressors, and mechanical circulatory support devices. Because mixed shock portends high mortality and morbidity, familiarity with quality, contemporary clinical evidence surrounding available therapeutic tools is needed to address the resultant wide range of complications that can arise. This review integrates pathophysiology principles and clinical recommendations to provide an organized, topic-based review of the nuanced intricacies of managing sepsis in the CICU.

Urine Output Monitoring and Acute Kidney Injury in Non-mammalian Exotic Animal Critical Care

Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to birds, reptiles, and amphibians. These species present unique challenges with AKI management, such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for non-mammalian exotic species.

Urine Output Monitoring and Acute Kidney Injury in Mammalian Exotic Animal Critical Care

Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to exotics. Exotic animals present unique challenges with AKI management such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for exotic companion mammals. The following article will discuss the same in non-mammalian patients.

Balanced Salt Solutions for Critically Ill Patients: Nonplused and Back to Basics

OBJECTIVES

The purpose of this article is to summarize the results of major randomized controlled trials (RCTs) comparing clinical outcomes of critically ill patients treated with normal saline (NS) or balanced salt solutions (BSSs), address discordant results of these studies, and provide direction for future investigations.

DATA SOURCES

PubMed (2011 to January 2022) with bibliographies of retrieved articles searched for additional articles.

STUDY SELECTION AND DATA EXTRACTION

RCTs comparing NS and BSSs in critically ill adult patients.

DATA SYNTHESIS

Recently published large RCTs comparing NS with BSSs in heterogeneous populations of intensive care unit patients did not find significant differences in mortality, despite positive findings in some end points in prior RCTs. However, there were a number of methodologic issues common to the RCTs including: varying study designs and end points, clinician discretion for the majority or all treatments other than the primary intervention fluid, heterogeneous patients with varying levels of acuity, and lack of power to investigate potential subgroup differences. In addition, there were problematic issues related to blinding and use of nonstudy fluids.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Intravenous fluids are a mainstay of supportive care for critically ill patients. Similar to the so-called crystalloid-colloid debate, there has been a long-standing debate among critical care clinicians and researchers concerning the preferred crystalloid solution, NS versus one of the available BSSs.

CONCLUSIONS

Despite the recent publication of large multicenter RCTs, the preferred resuscitation fluid, NS or a BSS, for critically ill patients is still open for debate, although the available investigations do provide some direction for clinicians and for future investigations.

Balanced Crystalloid versus Saline in Adults with Traumatic Brain Injury: Secondary Analysis of a Clinical Trial

Balanced crystalloids may improve outcomes compared with saline for some critically ill adults. Lower tonicity of balanced crystalloids could worsen cerebral edema in patients with intracranial pathology. The effect of balanced crystalloids versus saline on clinical outcomes in patients with traumatic brain injury (TBI) requires further study. We planned an a priori subgroup analysis of TBI patients enrolled in the pragmatic, cluster-randomized, multiple-crossover Isotonic Solutions and Major Adverse Renal Events Trial (SMART) (ClinicalTrials.gov: NCT02444988, NCT02547779). Primary outcome was 30-day in-hospital mortality. Secondary outcomes included hospital discharge disposition (home, facility, death). Regression models adjusted for pre-specified baseline covariates compared outcomes. TBI patients assigned to balanced crystalloids (n = 588) and saline (n = 569) had similar baseline characteristics including Injury Severity Score 19 (10); mean maximum head/neck Abbreviated Injury Score, 3.4 (1.0). Isotonic crystalloid volume administered between intensive care unit admission and first of hospital discharge or 30 days was 2037 (3470) mL and 1723 (2923) mL in the balanced crystalloids and saline groups, respectively (p = 0.18). During the study period, 94 (16%) and 82 (14%) patients (16%) died in the balanced crystalloid and saline groups, respectively (adjusted odds ratio [aOR], 1.03; 95% confidence interval [CI], 0.60 to 1.75; p = 0.913). Patients in the balanced crystalloid group were more likely to die or be discharged to another medical facility (aOR 1.38 [1.02-1.86]; p = 0.04). Overall, balanced crystalloids were associated with worse discharge disposition in critically injured patients with TBI compared with saline. The confidence intervals cannot exclude a clinically relevant increase in mortality when balanced crystalloids are used for patients with TBI.

Limitations of standard cost-effectiveness methods for health technology assessment of treatments for rare, chronic diseases: a case study of treatment for cystic fibrosis

OBJECTIVES

Cost-effectiveness analysis (CEA) is useful to assess the value of health care interventions based on clinical effectiveness and costs. However, standard CEA methods make important assumptions that may significantly increase the incremental cost-effectiveness ratio (ICER) for lifelong treatments for rare, chronic diseases. We used the cost-effectiveness of elexacaftor/tezacaftor/ivacaftor and ivacaftor (ELX/TEZ/IVA) for the treatment of cystic fibrosis as a case study to explore how alternative assumptions for (1) discounting, (2) utility measures, (3) disease management costs, and (4) static drug pricing impact cost-effectiveness outcomes.

MATERIALS AND METHODS

Cost-effectiveness of ELX/TEZ/IVA was evaluated using base-case inputs and assumptions reflecting standard CEA methods and was then compared with cost-effectiveness estimates obtained with alternate assumptions: (1) applying a lower discount rate to health benefits (1.5%) than costs (3%); (2) including a treatment-specific utility increment; (3) excluding disease management costs incurred during the period of extended survival attributable to ELX/TEZ/IVA treatment; and (4) decreasing the price of ELX/TEZ/IVA following loss of exclusivity.

RESULTS

Modifying assumptions for these four factors together reduced the ICER by 75% from the base case, with the largest reduction (45%) occurring when the price trajectory was modified to allow for generic entry. Differential discounting, use of a treatment-specific utility increment, and exclusion of additional disease management costs each individually reduced the ICER by 36%, 14%, and 10%, respectively, from the base case.

CONCLUSIONS

This study illustrates the impact that modifications to standard CEA methods may have on measures of cost-effectiveness for rare, chronic diseases.

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.

Dispelling myths and misconceptions about the treatment of acute hyperkalemia

Hyperkalemia represents a widespread and potentially lethal condition that affects millions of people across their lives. Despite the prevalence and severity of the condition, there are no consensus guidelines on the treatment of hyperkalemia or even a standard definition. Herein, we provide a succinct review of what we believe to be the most significant misconceptions encountered in the emergency care of hyperkalemia, examine current available literature, and discuss practical points on several modalities of hyperkalemia treatment. Additionally, we review the pathophysiology of the electrocardiographic effects of hyperkalemia and how intravenous calcium preparations can antagonize these effects. We conclude each section with recommendations to aid emergency physicians in making safe and efficacious choices for the treatment of acute hyperkalemia.

Normal saline or balanced salt solutions for fluid administration with a focus on critical care and emergency medicine settings

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