A balancing act: drifting away from the reflexive use of "ab"normal saline

Maintenance intravenous fluids are the most frequently ordered medications for hospitalized children. Since the American Association of Pediatrics published national guidelines, there has been an increased reflexive use of isotonic solutions, especially 0.9% saline, as a prophylaxis against hyponatremia. In this educational review, we discuss the potential deleterious effects of using 0.9% saline, including the development of hyperchloremia, metabolic acidosis, acute kidney injury, hyperkalemia, and a proinflammatory state. Balanced solutions with anion buffers cause relatively minimal harm when used in most children. While the literature supporting one fluid choice over the other is variable, we highlight the benefits of balanced solutions over saline and the importance of prescribing fluid therapy that is individualized for each patient.

Determinants of fluid use and the association between volume of fluid used and effect of balanced solutions on mortality in critically ill patients: a secondary analysis of the BaSICS trial

PURPOSE

Fluid use could modulate the effect of balanced solutions (BS) on outcome of intensive care unit (ICU) patients. It is uncertain whether fluid use practices are driven more by patient features or local practices. It is also unclear whether a "dose-response" for the potential benefits of balanced solutions exists.

METHODS

The secondary analysis of the Balanced Solution in Intensive Care Study (BaSICS) compared 0.9% saline versus Plasma-Lyte 148® (BS) for fluid therapy in the ICU. The relative contribution of patient features and enrolling site (the random effect) on the volume of fluid used up to day 3 after admission was assessed using different methods, including a Bayesian regression, a frequentist mixed model, and a random forest, all adjusted for relevant patient confounders. Subsequently, a variety of methods were used to assess whether volume of fluid used modulated the effect of BS on 90-day mortality, including a traditional subgroup analysis for patients that remained alive and in the ICU up to 3 days, a Bayesian network accounting for competing risks, and an analysis based on site practices.

RESULTS

10,505 patients were analyzed. Median fluid use in the BS arm and in the 0.9% saline arm were 2500 mL and 2488 mL, respectively. The random effect in the Bayesian regression explained 0.32 (95% credible intervals (CrI) 0.24-0.41) of all model variance (0.33, 95% credible intervals from 0.32-0.35). Frequentist and random forest models produced similar results. In the analysis including only patients alive and in the ICU at 3 days, there was a strong suggestion of interaction between fluid use and the effect of BS, driven mostly by a lower mortality with BS compared to 0.9% saline as fluid use increased for patients with sepsis. These results were consistent in the Bayesian network analysis and in an analysis based on site practices, where septic patients enrolled to BS at high fluid use sites had a lower mortality (absolute risk reduction of - 0.13 [95% credible interval - 0.27 to - 0.01]; 0.98 probability of benefit).

CONCLUSION

Baseline patient characteristics collected in the BaSICS trial explain less of the variance of fluid use during the first 3 days than the enrolling site. Volume of fluid used and the effects of BS appear to interact, mostly in the sepsis subgroup where there was a strong association between fluid use after enrollment and the effect of BS on 90-day mortality.

Intravenous maintenance fluid therapy practice in the pediatric acute and critical care settings: a European and Middle Eastern survey

The ideal fluid for intravenous maintenance fluid therapy (IV-MFT) in acutely and critically ill children is controversial, and evidence-based clinical practice guidelines are lacking and current prescribing practices remain unknown. We aimed to describe the current practices in prescribing IV-MFT in the context of acute and critically ill children with regard to the amount, tonicity, composition, use of balanced fluids, and prescribing strategies in various clinical contexts. A cross-sectional electronic 27-item survey was emailed in April-May 2021 to pediatric critical care physicians across European and Middle East countries. The survey instrument was developed by an expert multi-professional panel within the European Society of Pediatric and Neonatal Intensive Care (ESPNIC). A total of 154 respondents from 35 European and Middle East countries participated (response rate 64%). Respondents were physicians in charge of acute or critically ill children. All respondents indicated they routinely use a predefined formula to prescribe the amount of IV-MFT and considered fluid balance monitoring very important in the management of acute and critically ill children. The use of balanced solution was preferred if there were altered serum sodium and chloride levels or metabolic acidosis. Just under half (42%, 65/153) of respondents believed balanced solutions should always be used. Respondents considered the use of isotonic IV solutions as important for acute and critically ill children. In terms of the indication and the composition of IV-MFT prescribed, responses were heterogeneous among centers. Almost 70% (107/154) respondents believed there was a gap between current practice and what they considered ideal IV-MFT due to a lack of guidelines and inadequate training of healthcare professionals.   Conclusions: Our study showed considerable variability in clinical prescribing practice of IV-MFT in acute pediatric settings across Europe and the Middle East. There is an urgent need to develop evidence-based guidelines for IV-MFT prescription in acute and critically ill children. What is Known: • The administration of maintenance intravenous fluid therapy is a standard of care for a lot of hospitalized children • Maintenance intravenous fluid therapy prescriptions are often based on Holliday and Segar's historical guidelines even if this practice has been associated with several complications. What is New: • This study provided information on the prescribing practice regarding fluid restriction, fluid tonicity, and balance. • This study showed considerable variability in clinical prescribing practice of intravenous maintenance fluid therapy across Europe and the Middle East.

Hierarchical endpoint analysis using win ratio in critical care: An exploration using the balanced solutions in intensive care study (BaSICS)

PURPOSE

To reanalyze the results of the Balanced Solutions in Intensive Care Study (BaSICS) through hierarchical endpoint analysis with win ratio.

METHODS

All patients with full data in BaSICS trial were elected for the analysis. BaSICS compared balanced solutions (Plasma Lye 148) versus 0.9% saline in critically ill patients requiring fluid challenge. The win ratio was defined as a hierarchical endpoint of 90-day mortality, recepit of kidney replacement therapy, hospital length-of-stay (LOS), and intensive care unit (ICU) LOS. Both unstratified and stratified (by admission type: planned admission, unplanned admission with sepsis, and unplanned admission without sepsis) approaches were used. A subgroup analysis was performed in patients with traumatic brain injury.

RESULTS

A total of 10,490 patients were included in the analysis, resulting in 27,587,566 unique combinations for unstratified WR. Unstratified Win ratio was 1.02 (95% confidence interval 0.97; 1.07), which was similar to stratified WR. No stratum in the stratified analysis resulted in significant results. Subgroup analysis confirmed the possible harm of balanced solutions in traumatic brain injury patients (WR 0.80; 95% confidence interval 0.64; 0.99).

CONCLUSION

In this reanalysis of BaSICS, a win ratio analysis largely replicated the results of the main trial, yielding neutral results except for the subgroup of patients with traumatic brain injury where a signal of harm was found.

0.9% Sodium chloride solution versus Plasma-Lyte 148 versus compound sodium lacTate solution in children admitted to PICU-a randomized controlled trial (SPLYT-P): study protocol for an intravenous fluid therapy trial

Background

Intravenous fluid therapy represents the most common intervention critically ill patients are exposed to. Hyperchloremia and metabolic acidosis associated with 0.9% sodium chloride have been observed to lead to worse outcomes, including mortality. Balanced solutions, such as Plasma-Lyte 148 and Compound Sodium Lactate, represent potential alternatives but the evidence on optimal fluid choices in critically ill children remains scarce. This study aims to demonstrate whether balanced solutions, when used as intravenous fluid therapy, are able to reduce the incidence of a rise in serum chloride level compared to 0.9% sodium chloride in critically ill children.

Methods

This is a single-centre, open-label randomized controlled trial with parallel 1:1:1 assignment into three groups: 0.9% sodium chloride, Plasma-Lyte 148, and Compound Sodium Lactate solutions for intravenous fluid therapy. The intervention includes both maintenance and bolus fluid therapy. Children aged < 16 years admitted to intensive care and receiving intravenous fluid therapy during the first 4 h of admission are eligible. The primary outcome measure is a ≥ 5mmol/L increase in serum chloride level within 48 h post-randomization. The enrolment target is 480 patients. The main analyses will be intention-to-treat.

Discussion

This study tests three types of intravenous fluid therapy in order to compare the risk of hyperchloremia associated with normal saline versus balanced solutions. This pragmatic study is thereby assessing the most common intervention in paediatric critical care.

This is a single-centre open-label study with no blinding at the level of delivery of the intervention. Certain paediatric intensive care unit (PICU) patient groups such as those admitted with a cardiac condition or following a traumatic brain injury are excluded from this study.

Trial registration

The study has received ethical approval (HREC/19/QCHQ/53177: 06/06/2019). It is registered in the Australian New Zealand Clinical Trials Registry (ACTRN12619001244190) from 9th September 2019. Recruitment commenced on 12th November 2019. The primary results manuscript will be published in a peer-reviewed journal.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05376-5.

Fluid Resuscitation: History, Physiology, and Modern Fluid Resuscitation Strategies

Intravenous (IV) fluids are among the most common interventions performed in the emergency department. They are at times lifesaving, but if used recklessly can be harmful. Given their ubiquity, it is important to understand the history, physiology, and current strategies that govern the use of IV fluids during the resuscitation of the critically ill.

Impact of chloride and strong ion difference on ICU and hospital mortality in a mixed intensive care population

BACKGROUND

Abnormal chloride levels are commonly observed in critically ill patients, but their clinical relevance remains a matter of debate. We examined the association between abnormal chloremia and ICU and hospital mortality. To further refine findings and integrate them into the ongoing discussion on the detrimental effects of chloride-rich solutions, the impact of strong ion difference (SID) on the same end points was assessed.

METHODS

Retrospective cohort study in an academic tertiary intensive care unit on 8830 adult patients who stayed at least 24 h in the ICU was carried out. Patients admitted after elective cardiac surgery were treated as a separate subgroup (n = 2350). Analyses were performed using multivariable logistic regression. All statistical models were extensively adjusted for confounders, including comorbidity, admission diagnosis, other electrolytes and acid-base parameters.

RESULTS

Severe hyperchloremia (>110 mmol/L), but not low (SID) was significantly associated with increased mortality in the ICU (odds ratio vs. normochloremia 1.81; 95 % CI 1.32-2.50; p < 0.001) and the hospital (odds ratio 1.49; 95 % CI 1.14-1.96; p = 0.003). Hyperchloremia and low (SID) were encountered in the majority of patients admitted after cardiac surgery (in 86.9 and 47.2 %, respectively), but were not negatively associated with mortality.

CONCLUSIONS

In the ICU, hyperchloremia at admission was associated with negative outcome. On the other hand, decreased strong ion difference did not have an impact on mortality, precluding a simple extrapolation of these findings to the ongoing discussion on the detrimental effects of chloride-rich solutions. This notion is fueled by the finding that hyperchloremia after cardiac surgery, frequently encountered and probably fluid-induced, did not seem to be deleterious.

Fluid Composition and Clinical Effects

The range of intravenous fluids available for therapeutic use and the differing indications are diverse. A solid understanding of the composition of different types of fluids is essential to understanding the physiologic effects following administration and the appropriate clinical application. In this review, the authors describe the different fluids commonly available and discuss the potential benefits and harms depending on the clinical circumstances.

Fluid as a Drug: Balancing Resuscitation and Fluid Overload in the Intensive Care Setting

Intravenous fluid resuscitation is ubiquitous throughout medicine and is often considered a benign procedure. Yet, there is now clear recognition of the potential harms of fluid overload after initial resuscitation. In recent years, there has also been an increasing focus on comparing various resuscitation fluids with respect to both benefits and risks. Studies have examined colloids, such as albumin and starches, against the clinical standard of crystalloids. In addition, evidence has emerged to suggest that outcomes may be different between resuscitation with chloride-rich vs balanced crystalloid solutions. In this article, we review the current literature regarding choice of intravenous fluids for resuscitation in the intensive care setting and describe the dangers associated with fluid overload in critically ill patients.