Efficacy and safety of isotonic versus hypotonic intravenous maintenance fluids in hospitalized children: an updated systematic review and meta-analysis of randomized controlled trials

Saline versus balanced crystalloids for hydration post-kidney biopsy

BACKGROUND

Isotonic fluids are becoming the standard for hydration and maintenance fluid therapy, but there is no consensus on the optional choice among the different types of isotonic solution.

METHODS

This study is a single-center, non-randomized controlled trial at Kobe University Hospital, Japan, between April 2021 and March 2023. The study included pediatric patients aged 1-19 years who underwent kidney biopsies. From April 2021 to March 2022, 0.9% sodium chloride (saline) was administered, and from April 2022 to March 2023, balanced crystalloids were used. The primary outcome was the occurrence of hyponatremia (< 137 mEq/L) after a kidney biopsy. Secondary outcomes included other electrolyte balances, blood gas parameters, creatinine-based estimated glomerular filtration rate (Cr-eGFR), and arginine vasopressin concentrations (UMIN Clinical Trial Registry: UMIN 000044330).

RESULTS

Of 61 patients enrolled, 2 were excluded, leaving 34 in the saline group and 25 in the balanced crystalloid group. No hyponatremia occurred, and serum sodium concentrations were similar between both groups (138.7 vs. 138.9 mEq/L, P = 0.08). The saline group showed a greater increase in serum chloride (+ 1.7 vs. + 0.2, P < 0.01) and a greater decrease in HCO3- concentrations (- 0.6 vs. + 0.9, P < 0.01). There were minimal changes in pH (- 0.01 vs. - 0.01, P = 0.99) and Cr-eGFR (- 1.5 vs. + 1.1 mL/min/1.73 m2, P = 0.96) in both groups.

CONCLUSIONS

During pediatric kidney biopsy, both saline and balanced crystalloids were effective in preventing hyponatremia. Although saline infusion results in higher serum chloride concentrations and lower blood HCO3- concentrations than balanced crystalloids infusion, the clinical significance was minimal.

Ideal burn resuscitation: a step toward resolving the dilemma in acute flame burn management

Following severe burns, the predominant concern is significant fluid loss, for which balanced crystalloid solutions are widely recommended as the primary intravenous resuscitation fluids. However, current literature lacks a clear distinction among various buffered crystalloid types that might be most effective in the early resuscitation of burn patients. This retrospective study was conducted to identify the optimal resuscitation fluid for major burns and to assess the clinical outcomes associated with isotonic crystalloid solutions compared to hypotonic crystalloids, specifically in terms of urinary output, acid-base balance, and electrolyte stability. Conducted over one year at the Burn Care Center of the Pakistan Institute of Medical Sciences in Islamabad, the study involved 132 patients who were divided equally into two groups, each with 66 patients. Group A received isotonic crystalloids, while Group B was administered hypotonic crystalloids. The mean pre-infusion levels of sodium, potassium, bicarbonate, and pH were identical across both groups. Following infusion, sodium and chloride levels remained within normal ranges in the isotonic group. Among children under 12 years of age, none in the isotonic group exhibited a urine output below 1 ml/kg/h, while 22.7% of those in the hypotonic group had urine output below this threshold. In patients over 12 years, only one individual in the isotonic group presented a urine output of less than 0.5 ml/kg/h, compared to 19.7% of those in the hypotonic group. These findings indicate that isotonic crystalloids are superior to hypotonic crystalloids, demonstrating improved urinary output and better serum electrolyte balance in patients with severe burns.

Update on perioperative fluids

Adequate fluid management in the perioperative period in paediatric patients is essential for restoring and maintaining homeostasis and ensuring adequate tissue perfusion. A well-designed infusion regimen is crucial for preventing severe complications such as hyponatraemic encephalopathies. The composition of perioperative fluid solutions is now guided by an understanding of extracellular fluid physiology. Various crystalloid and colloidal products are available for use, but a comprehensive approach requires careful consideration of their drawbacks and limitations. Additionally, the unique characteristics of different patient groups must be taken into account. This review will provide the reader with physiological considerations for perioperative fluids and describe indications for perioperative intravenous fluid therapy in paediatric patients. The current evidence on perioperative fluid therapy is finally summarised in practical recommendations.

Fluids and body composition during anesthesia in children and adolescents: A pilot study

The purpose of this study is to evaluate the intracellular and extracellular volume before and after anesthesia in order to ascertain their variations and determine the potential utility of this information in optimizing intraoperative fluid administration practices. A bioimpedance spectroscopy device (body composition monitor, BCM) was used to measure total body fluid volume, extracellular volume, and intracellular volume. BCM measurements were performed before and after general anesthesia in unselected healthy children and adolescents visiting the Pediatric Institute of Southern Switzerland for low-risk surgical procedures hydrated with an isotonic solution. In 100 children and adolescents aged 7.0 (4.8-11) years (median and interquartile range), the average total body water increased perioperatively with a delta value of 182 (0-383) mL/m2 from pre- to postoperatively, as well as the extracellular water content, which had a similar increase with a delta value of 169 (19-307) mL/m2. The changes in total body water and extracellular water content significantly correlated with the amount of fluids administered. The intracellular water content did not significantly change.   Conclusion: Intraoperative administration of isotonic solutions results in a significant fluid accumulation in low-risk schoolchildren during general anesthesia. The results suggest that children without major health problems undergoing short procedures do not need any perioperative intravenous fluid therapy, because they are allowed to take clear fluids up to 1 h prior anesthesia. In future studies, the use of BCM measurements has the potential to be valuable in guiding intraoperative fluid therapy. What is Known: • Most children who undergo common surgical interventions or investigations requiring anesthesia are nowadays hydrated at a rate of 1700 mL/m2/day with an isotonic solution. • The use bioimpedance spectroscopy for the assessment of fluid status in healthy children has already been successfully validated. • The bioimpedance spectroscopy is already currently widely used in various nephrological settings to calculate fluid overload and determine patient's optimal fluid status. What is New: • Routine intraoperative fluid administration results in a significant fluid accumulation during general anesthesia in low-risk surgical procedures. • This observation might be relevant for children and adolescents with conditions predisposing to fluid retention. • In future studies, the use of BCM measurements has the potential to be valuable in guiding intraoperative fluid therapy.

Intravenous maintenance fluid therapy in acutely and critically ill children: state of the evidence

Intravenous maintenance fluid therapy (IV-MFT) is one of the most prescribed, yet one of the least studied, interventions in paediatric acute and critical care settings. IV-MFT is not typically treated in the same way as drugs with specific indications, contraindications, compositions, and associated adverse effects. In the last decade, societies in both paediatric and adult medicine have issued evidence-based practice guidelines for the use of intravenous fluids in clinical practice. The main objective of this Viewpoint is to summarise and compare the rationales on which these international expert guidelines were based and how these recommendations affect IV-MFT practices in paediatric acute and critical care. Although these guidelines recommend the use of isotonic fluids as a standard in IV-MFT, some discrepancies and uncertainties remain regarding the systematic use of balanced fluids, glucose and electrolyte requirements, and appropriate fluid volume. IV-MFT should be considered in the same way as any other prescription drug and none of the components of IV-MFT prescription should be overlooked (ie, choice of drug, dosing rate, duration of treatment, and de-escalation). Furthermore, most evidence that was used to inform the guidelines comes from high-income countries. Although some principles of IV-MFT are universal, the direct relevance to and feasibility of implementing the guidelines in low-income and middle-income countries is uncertain.