Incidence of postoperative hyponatremia and complications in critically-ill children treated with hypotonic and normotonic solutions

Meningomyelocele Perioperative Management in Neonatal: Case Series

BACKGROUND

Myelomeningocele (MMC) is a congenital malformation affecting the central nervous system, categorized as a neural tube defect (NTDs). In untreated cases, the mortality rate within the first six months of life ranges from 35% to 70%. Globally, its incidence is estimated 0.8 to 1 per 1000 live births, and rates are higher in Asia and lower socioeconomic groups. This disease imposes a significant treatment cost and burden due to life-long disabilities. In less developed or developing countries, delays in diagnosis can lead to complications such as infection and rupture. Although rupture is a rare complication in MMC, there are limited studies that have reported it. This study aims to discuss the perioperative management and potential complications of ruptured MMC.

METHOD

This study presents four cases of ruptured MMC that were referred from private hospitals and managed by Hasan Sadikin General Hospital in West Java, Indonesia. Each patiens underwent a clinical assessment and diagnostic evaluation upon arrival, followed by perioperative theraphy and management of any complications that emerged during treatment.

RESULT

In three of the four cases, the children were over 24 h old when they were admitted to the hospital. Three cases were located in the lumbosacral region while one case was located in the thoracic region. Upon arrival, the clinical presentations we observed included microcephaly, small for gestational age (SGA) and congenital talipes equionavrus (CTEV). And we found several complications included wound dehisence, respiratiory failure, hydrocephalus, leg weakness, menigitis and sepsis after surgery.

CONCLUSIONS

Perioperative management is highlighted as vital, necessitating a multidisciplinary approach and precise surgical techniques to mitigate severe complications.

Post-operative dysnatremia is associated with adverse early outcomes after surgery for congenital heart disease

BACKGROUND

Dysnatremia is a common disorder in critically ill surgical children. The study's aim is to determine the prevalence of dysnatremia and its association with outcomes after surgery for congenital heart disease (CHD).

METHODS

This is a single-center retrospective cohort study of children <18 years of age undergoing surgery for CHD between January 2012 and December 2014. Multivariable logistic regression analysis was used to evaluate the relationship between dysnatremia and outcomes during the perioperative period. A total of 1345 encounters met the inclusion criteria.

RESULTS

The prevalence of pre- and post-operative dysnatremia were 10.2% and 47.1%, respectively. Hyponatremia occurred in 19.1%, hypernatremia in 25.6%. Hypernatremia at 24, 48, and 72 h post-operative was associated with increased hospital mortality (odds ratios (OR) [95% confidence intervals (CI)] 3.08 [1.16-8.17], p = 0.024; 4.35 [1.58-12], p = 0.0045; 4.14 [1.32-12.97], p = 0.0148, respectively. Hypernatremia was associated with adverse neurological events 3.39 [1.12-10.23], p = 0.0302 at 48 h post-operative. Hyponatremia was not associated with any adverse outcome in our secondary analysis.

CONCLUSIONS

Post-operative dysnatremia is a common finding in this heterogeneous cohort of pediatric cardiac-surgical patients. Hypernatremia was more prevalent than hyponatremia and was associated with adverse early post-operative outcomes.

IMPACT

Our study has shown that dysnatremia was highly prevalent in children after congenital heart surgery with hypernatremia associated with adverse outcomes including mortality. It is important to understand fluid and sodium regulation in the post-operative period in children with congenital heart disease to better address fluid overload and associated electrolyte imbalances and acute kidney injury. While clinicians are generally very aware of the importance of hyponatremia in critically ill children, similar attention should be given to hypernatremia in this population.

Association of early hyponatremia and the development of acute kidney injury in critically ill children

BACKGROUND

Hyponatremia is an independent prognostic factor for mortality; however, the reason for this remains unclear. An observed relationship between hyponatremia and the development of acute kidney injury (AKI) has been reported in certain disease states, but hyponatremia has not been evaluated as a predictor of AKI in critically ill patients or children.

METHODS

This is a single-center retrospective cohort study of critically ill children admitted to a tertiary care center. We performed regression analysis to assess the association between hyponatremia at ICU admission and the development of new or worsening stage 2 or 3 (severe) AKI on days 2-3 following ICU admission.

RESULTS

Among the 5057 children included in the study, early hyponatremia was present in 13.3% of children. Severe AKI occurred in 9.2% of children with hyponatremia compared to 4.5% of children with normonatremia. Following covariate adjustment, hyponatremia at ICU admission was associated with a 75% increase in the odds of developing severe AKI when compared to critically ill children with normonatremia (aOR 1.75, 95% CI 1.28-2.39). Evaluating sodium levels continuously, for every 1 mEq/L decrease in serum sodium level, there was a 0.05% increase in the odds of developing severe AKI (aOR 1.05, 95% CI 1.02-1.08). Hyponatremic children who developed severe AKI had a higher frequency of kidney replacement therapy, AKI or acute kidney disease at hospital discharge, and hospital mortality when compared to those without.

CONCLUSIONS

Hyponatremia at ICU admission is associated with the development of new or worsening AKI in critically ill children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Postoperative hyponatremia in neonates with esophageal atresia and tracheoesophageal fistula receiving restricted hypotonic fluids

Background

During the postoperative course following neonatal surgery, several stimuli like respiratory distress, pain, and stress cause the release of the antidiuretic hormone which can induce hyponatremia. This hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH) in neonates can lead to neurologic impairment and in severe cases can cause significant morbidity and mortality. Lung involvement in neonates undergoing TEF makes this subset of patients vulnerable to this entity because most of them are sick and require ventilation in the postoperative period. The incidence of postoperative hyponatremia following neonatal surgery has not been studied vastly. To the best of our knowledge, this is the first prospective study that has analyzed the incidence of postoperative hyponatremia in this vulnerable population.

Methods

Prospective observational study to assess the incidence of postoperative hyponatremia in neonates with esophageal atresia and tracheoesophageal fistula (EA and TEF) receiving restricted hypotonic fluids. As per the unit policy N/4 5% D is given in the postoperative period. Most neonatal units follow a protocol in which fluid is hiked daily to reach 150 ml/kg/day in 5–7 days. However, in our neonatal surgical unit a protocol to restrict the maintenance fluid at 100 ml/kg/day irrespective of day of life is followed.

Results

Out of a total of 90 neonates (270 sodium measurements), we identified 16 with hyponatremia (11%). Most of the neonates had mild hyponatremia(130–135 meq/l). The incidence of moderate and severe hyponatremia was low.

Conclusion

Postoperative restriction of fluids especially in neonates who are at a high risk for developing SIADH can lead to decreased incidence of severe hyponatremia.

Postoperative dysnatremia in infants after open-heart surgery occurs frequently and is associated with prolonged intensive care length of stay

BACKGROUND

Dysnatremia after surgery for congenital heart disease (CHD) is well known and has been associated with prolonged pediatric intensive care unit length of stay (PICU-LOS). Fluctuations in plasma sodium levels occur perioperatively. The primary aim of the study was to evaluate the occurrence of dysnatremia during the first 48 h after surgery and whether it was associated with PICU-LOS. The secondary aim was to evaluate if the degree of sodium fluctuations was associated with PICU-LOS.

METHODS

A retrospective observational, single-center study including infants undergoing surgery for CHD. The highest and lowest plasma sodium value was registered for the prespecified time periods. PICU-LOS was analyzed in relation to the occurrence of dysnatremia and the degree of plasma sodium fluctuations. The occurrence of dysnatremia was evaluated in relation to surgical procedure and fluid administration.

RESULTS

Two hundred and thirty infants who underwent 249 surgical procedures were included. Dysnatremia developed in more than 60% within 48 h after surgery. Infants with normonatremia had a 40%-50% shorter PICU-LOS among children in RACHS-1 category 3-6, compared with infants developing either hypo- or hyper-/hyponatremia within 48 h after surgery (p = .006). Infants who had a decline of plasma sodium >11 mmol/L had almost double the PICU-LOS compared to those with a decline of <8 mmol/L.

CONCLUSION

Dysnatremias were common after surgery for CHD and associated with prolonged PICU-LOS. The degree of decline in plasma sodium was significantly associated with PICU-LOS. Fluid administration both in terms of volume and components (blood products and crystalloids) as well as diuresis were related to the occurrence of dysnatremias.

Efficacy and Safety of Isotonic and Hypotonic Intravenous Maintenance Fluids in Hospitalised Children: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Hyponatraemia is a known complication in hospitalised children receiving maintenance intravenous fluid. Several studies have been published to investigate the efficacy and safety of intravenous fluids in children. However, there is still an ongoing debate regarding the ideal solution to be used in the paediatric population. Therefore, the aim of this meta-analysis was to investigate the safety and efficacy of administering isotonic versus hypotonic intravenous maintenance fluid in hospitalised children. An extensive search was undertaken on PubMed, Web of Science, Scopus, ScienceDirect, Google Scholar and Cochrane Library on 28 December 2020. Only randomised controlled trials (RCTs) were included. We used the random-effects model for all analyses. Risk ratio (RR) and mean difference with 95% confidence intervals (CIs) were used for dichotomous and continuous outcomes, respectively. The quality of each study was assessed using the Joanna Briggs Institute critical appraisal tool for RCTs. This study is registered with PROSPERO (CRD42021229067). Twenty-two RCTs with a total of 3795 participants were included. The studies encompassed surgical and medical patients admitted to intensive care unit as well as to general wards. We found that hypotonic fluid significantly increases the risk of hyponatremia at both ≤24 h (RR 0.34; 95% CI: 0.26–0.43, p < 0.00001) and >24 h (RR 0.48; 95% CI: 0.36–0.64, p < 0.00001). Isotonic fluid increases the risk of hypernatraemia at ≤24 h (RR 2.15; 95% CI: 1.24–3.73, p = 0.006). The prevalence of hyponatraemia was also higher in the hypotonic group at both ≤24 h (5.7% vs. 23.3%) and >24 h (6.0% vs. 26.3%). There was no statistically significant difference in the risk of developing adverse outcomes between the two groups. Mean serum and urine sodium as well as serum osmolality/osmolarity was lower in the hypotonic group. Isotonic solution is protective against the development of hyponatraemia while hypotonic solution increases the risk of hyponatraemia.

Hyponatraemia in a Lao paediatric intensive care unit: Prevalence, associations and intravenous fluid use

AIM

Hyponatraemia is a common and potentially deadly complication affecting hospitalised children world-wide. Hypotonic intravenous fluids can be a significant exacerbating factor. Exclusive use of isotonic fluids, coupled with rigorous blood monitoring, has proven effective in reducing hyponatraemia in developed settings. In developing countries, where hyponatraemia is often more common and severe, different factors may contribute to its incidence and detection. We aimed to determine the prevalence and disease associations of hyponatraemia and describe the intravenous maintenance fluid prescribing practices in a Lao paediatric intensive care unit.

METHODS

We conducted a cross-sectional study of 164 children aged 1 month to 15 years admitted to intensive care at a tertiary centre in Lao People's Democratic Republic (PDR) and recorded their serum sodium and clinical data at admission and on two subsequent days.

RESULTS

Hyponatraemia was detected in 41% (67/164, confidence interval 34-48%) of children, the majority of which was mild (34%, 56/164) and present at admission (35%, 55/158). Hyponatraemia was more common in malnourished children (odds ratio (OR) 2.3, P = 0.012) and females (OR 1.9, P = 0.045). Hyponatraemia correlated with death or expected death after discharge (OR 2.2, P = 0.015); 88% received maintenance intravenous fluids, with 67% of those receiving a hypotonic solution. Electrolyte testing was only performed in 20% (9/46) of patients outside the study protocol.

CONCLUSIONS

Hyponatraemia is highly prevalent in critically ill children in Lao PDR, as is the continued use of hypotonic intravenous fluids. With financial and practical barriers to safely detecting and monitoring electrolyte disorders in this setting, this local audit can help promote testing and has already encouraged changes to fluid prescribing.

Incidence of hyponatraemia following the use of three different intravenous fluids in paediatric surgery

BACKGROUND

It is a common practice to administer 4.3% dextrose in 0.18% saline peri-operatively and for routine fluid maintenance in the paediatric age group. Concerns have been expressed about the risk of hyponatraemia associated with the administration of hypotonic intravenous fluids, hence the need to re-evaluate our practice. This study aims to evaluate the relative incidence of intra-operative hyponatraemia following the use of isotonic and hyopotonic intravenous fluids.

PATIENTS AND METHODS

This randomised double-blind clinical trial recruited consecutive American Society of Anaesthesiologists physical status Class I and II children aged between 6 months and 17 years scheduled for various minor elective surgical procedures. The patients received one of 3 intravenous infusions for intra-operative fluid management. Group I received 4.3% dextrose in 0.18 saline (n = 25), Group II received normal saline (n = 20) and Group III received Ringer's lactate (n = 20). Blood samples were collected before the surgery and at the end of surgery for serum electrolytes.

RESULTS

One patient in each group developed moderate hyponatraemia intraoperatively. This constituted a 4% (1/25) incidence of intra-operative hyponatraemia among patients who had hypotonic maintenance fluid and a 5% (2/40) incidence in the isotonic maintenance groups. The incidence of hyponatraemia was therefore comparable between patients who had hypotonic and isotonic intra-operative maintenance fluids (P = 1.000).

CONCLUSION

We conclude that healthy children who have intraoperative hypotonic maintenance fluids during minor elective surgeries are not exposed to the additional risk of hyponatraemia compared to those who have isotonic fluids. The study of a larger sample size is recommended to further validate our findings.

Hospital-acquired Hyponatremia in Pediatric Intensive Care Unit

Objective:

The objective of the study was to evaluate the etiology of hospital-acquired hyponatremia (HAH) and its effects on morbidity and mortality in the Pediatric Intensive Care Unit (PICU) patients.

Design:

This study design was a prospective observational case–control study.

Setting:

this study was conducted at tertiary care PICU.

Materials and Methods:

All consecutive cases admitted with at least one measured serum sodium (P_Na) value were evaluated. Those with normal admission P_Na were followed till they develop hyponatremia (P_Na < 35 mEq/L) 7 days or PICU discharge whichever was earlier.

Results:

During the study period, 123 (19.6%) cases developed HAH and 126 patients remained isonatremic (control group). The admission P_Na 138.8 ± 3.03 mEq/L decreased to 132 ± 2.58 mEq/L (drop of 6.68 ± 3.39 mEq/L, P < 0.001) in HAH cases. The use of antidiuretic hormone (ADH)-stimulating drugs (odds ratio [OR]: 2.83, P = 0.01), postsurgical status (OR: 2.95, P = 0.006), and fluid intake ml/kg (OR: 1.0, P = 0.001) were found to be significant risk factors in HAH group on multivariate analysis. HAH cases had prolonged PICU stay (P = 0.000) and mechanical ventilation (P = 0.01), but no difference in the mortality when compared to controls.

Conclusions:

HAH is associated with increased fluid intake, presence of ADH-stimulating drugs or conditions, and postsurgical status and has an adverse effect on the outcome of PICU patients.

Iatrogenic Dysnatremias in Children with Acute Gastroenteritis in High-Income Countries: A Systematic Review

BACKGROUND

Acute gastroenteritis (AGE) causing dehydration with or without dysnatremias is a common childhood health challenge. While it is accepted that oral rehydration therapy is preferred, clinical factors or parent and healthcare provider preferences may lead to intravenous rehydration (IVR). Isotonic solutions are increasingly recommended in most scenarios requiring IVR. Nevertheless, children with AGE, having ongoing losses of water and electrolytes, represent a unique population.

OBJECTIVES

To evaluate the association between acquired dysnatremias and IVR in children with AGE.

METHODS

A systematic search of MEDLINE database was conducted through September 14, 2016. Observational studies and clinical trials conducted in high-income countries were included. The Grades of Recommendation, Assessment, Development, and Evaluation approach was used to evaluate the overall quality of evidence for each outcome.

RESULTS

603 papers were identified of which 6 were included (3 randomized controlled trials and 3 observational studies). Pooling of patient data was not possible due to significantly different interventions or exposures. Single studies results demonstrated that within 24 h, administration of isotonic saline was not associated with a significant decline in serum sodium while hypotonic solutions (0.2-0.45% saline) were associated, in one study, with mean serum sodium declines from 1.3 mEq/L (139.2, SD 2.9-137.9, SD 2.5) in 133 young infants (aged 1-28 months), to 5.7 (SD 3.1) mEq/L in a subgroup of 18 older children (age mean 5.8, SD 2.7 years). Both isotonic and hypotonic saline were shown to be associated with improvement of baseline hyponatremia in different studies. Baseline hypernatremia was corrected within 4-24 h in 81/83 (99.6%) children using hypotonic saline IVR.

CONCLUSION

There is a paucity of publications assessing the risk for acquired dysnatremias associated with IVR in children with AGE. Current high-quality evidence suggests that, short-term use of isotonic solutions is safe and effective in most children with AGE; hypotonic solutions may also be appropriate in some subpopulations, however, the quality of available evidence is low to very low. Further research investigating outcomes associated with IVR use beyond 24 h focusing on specific age groups is required.

Suitable intravenous fluid for preventing dysnatremia in children with gastroenteritis; a randomized clinical trial

Introduction: Gastroenteritis (GE) is one of the most common pediatric diseases. Hyponatremia commonly occurs by administering hypotonic fluids to GE and hospitalized children. Yet, there is no consensus on the ideal method of treatment.

Objectives: we aimed to assess suitable intravenous (IV) fluid for preventing dysnatremia in children with GE.

Patients and Methods: This is a double blind randomized clinical trial, which was conducted on infants of 6 months up to 14 years children with GE. Children were randomly assigned in 2 different groups. Group A; received 20 cc/kg 0.9% isotonic saline as a bolus, and 0.45% hypotonic saline as sum of maintenance fluid and volume deficit. Group B was treated with the same bolus and 0.9% isotonic saline with 20 mEq/L KCl as sum of maintenance fluid and volume deficit. Blood and urine samples were taken at admission, 4 and 24 hours. Data were analyzed by independent t test, Mann-Whitney U test, Friedmann test, chi-square and 2-tailed repeated measurements by SPSS version 19.

Results: Baseline hyponatremia and isonatremia were detected in 24 (31.5%) and 51 (67.1%) patients, respectively. Mean level of sodium at T0, T4 and T 24 mentioned no significant difference between groups. No hypernatremia was noted by administering isotonic saline. Results showed that 4 and 24 hours after administration isotonic saline, the mean plasma sodium differed significantly in baseline hyponatremic patients. However, no significant difference was noted after 4 and 24 hours in group A.

Conclusion: According to the considerable effect of isotonic saline on hyponatremic patients, it seems that administering isotonic fluids regardless of the types of dysnatremia can be recommended to lessen clinicians’ conflicting decision-making in selecting an appropriate fluid.

Perioperative fluid management and postoperative hyponatremia in children

Intravenous (IV) fluids are used ubiquitously when children undergo surgical procedures. Until recently, Holliday and Segar's guidelines for calculating maintenance fluids dictated fluid management strategies in postoperative pediatric patients. An increased recognition of hospital-acquired hyponatremia and its associated morbidity has led to a critical re-examination of IV fluid management in this population. Postsurgical patients are at high risk of developing hyponatremia due to the presence of non-osmotic stimuli for antidiuretic hormone release. Recent studies have established that, as they are administered in current practice, hypotonic maintenance fluids are associated with increased rates of hyponatremia. The best available data demonstrate that administration of isotonic fluid reduces hyponatremic risk. In this review, we discuss the collective data available on the subject and offer guidelines for fluid management and therapeutic monitoring.

Comparison of two maintenance electrolyte solutions in children in the postoperative appendectomy period: a randomized, controlled trial

OBJECTIVE

To compare two electrolyte maintenance solutions in the postoperative period in children undergoing appendectomy, in relation to the occurrence of hyponatremia and water retention.

METHODS

A randomized clinical study involving 50 pediatric patients undergoing appendectomy, who were randomized to receive 2,000mL/m(2)/day of isotonic (Na 150 mEq/L or 0.9% NaCl) or hypotonic (Na 30 mEq/L NaCl or 0.18%) solution. Electrolytes, glucose, urea, and creatinine were measured at baseline, 24h, and 48h after surgery. Volume infused, diuresis, weight, and water balance were analyzed.

RESULTS

Twenty-four patients had initial hyponatremia; in this group, 13 received hypotonic solution. Seventeen patients remained hyponatremic 48h after surgery, of whom ten had received hypotonic solution. In both groups, sodium levels increased at 24h (137.4±2.2 and 137.0±2.7mmol/L), with no significant difference between them (p=0.593). Sodium levels 48h after surgery were 136.6±2.7 and 136.2±2.3mmol/L in isotonic and hypotonic groups, respectively, with no significant difference. The infused volume and urine output did not differ between groups during the study. The water balance was higher in the period before surgery in patients who received hypotonic solution (p=0.021).

CONCLUSIONS

In the post-appendectomy period, the use of hypotonic solution (30 mEq/L, 0.18%) did not increase the risk of hyponatremia when compared to isotonic saline. The use of isotonic solution (150 mEq/L, 0.9%) did not favor hypernatremia in these patients. Children who received hypotonic solution showed higher cumulative fluid balance in the preoperative period.

The effect of NaCl 0.9% and NaCl 0.45% on sodium, chloride, and acid-base balance in a PICU population

OBJECTIVES

To study the effect of two intravenous maintenance fluids on plasma sodium (Na), and acid-base balance in pediatric intensive care patients during the first 24h of hospitalization.

METHODS

A prospective randomized controlled study was performed, which allocated 233 patients to groups: (A) NaCl 0.9% or (B) NaCl 0.45%. Patients were aged 1 day to 18 years, had normal electrolyte concentrations, and suffered an acute insult (medical/surgical).

MAIN OUTCOME MEASURED

change in plasma sodium. Parametric tests: t-tests, ANOVA, X(2) statistical significance level was set at α=0.05.

RESULTS

Group A (n=130): serum Na increased by 2.91 (±3.9)mmol/L at 24h (p<0.01); 2% patients had Na higher than 150 mmol/L. Mean urinary Na: 106.6 (±56.8)mmol/L. No change in pH at 0 and 24h. Group B (n=103): serum Na did not display statistically significant changes. Fifteen percent of the patients had Na<135 mmol/L at 24h. The two fluids had different effects on respiratory and post-operative situations.

CONCLUSIONS

The use of saline 0.9% was associated with a lower incidence of electrolyte disturbances.

Impact of perioperative hyponatremia in children: A narrative review

For more than 50 years, hypotonic fluids (crystalloids) have been the standard for maintenance fluid used in children. In the last decade, several studies have evaluated the risk of hyponatremia associated with the use of hypotonic vs isotonic fluids, which has lead to an intense debate. Children undergoing surgery have several stimuli for release of antidiuretic hormone, which controls renal water handling, including pain, nausea, vomiting, narcotic use and blood loss. The body’s primary defense against the development of hyponatremia is the ability of the kidneys to excrete free water and dilute urine. Increased levels of antidiuretic hormone can result in hyponatremia, defined as a plasma sodium level < 136 mmol/L, which causes cells to draw in excess water and swell. This manifests as central nervous system symptoms such as lethargy, irritability and seizures. The risk for symptomatic hyponatremia is higher in children than in adults. It represents an emergency condition, and early diagnosis, prompt treatment and close monitoring are essential to reduce morbidity and mortality. The widespread use of hypotonic fluids in children undergoing surgery is a matter of concern and more focus on this topic is urgently needed. In this paper, we review the literature and describe the impact of perioperative hyponatremia in children.

Hypotonic versus isotonic fluids in hospitalized children: a systematic review and meta-analysis

OBJECTIVE

To determine whether the use of hypotonic vs isotonic maintenance fluids confers an increased risk of hyponatremia in hospitalized children.

STUDY DESIGN

A search of MEDLINE (1946 to January 2013), the Cochrane Central Registry (1991 to December 2012), Cumulative Index for Nursing and Allied Health Literature (1990 to December 2012), and Pediatric Academic Societies (2000-2012) abstracts was conducted using the terms "hypotonic fluids/saline/solutions" and "isotonic fluids/saline/solutions," and citations were reviewed using a predefined protocol. Data on the primary and secondary outcomes were extracted from original articles by 2 authors independently. Meta-analyses of the primary and secondary outcomes were performed when possible.

RESULTS

A total of 1634 citations were screened. Ten studies (n = 893) identified as independent randomized controlled trials were included. Five studies examined subjects in the intensive care unit setting, including 4 on regular wards and 1 in a mixed setting. In hospitalized children receiving maintenance intravenous fluids, hyponatremia was seen more often in those receiving hypotonic fluids than in those receiving isotonic fluids, with an overall relative risk of 2.37 (95% CI, 1.72-3.26). Receipt of hypotonic fluids was associated with a relative risk of moderate hyponatremia (<130 mmol/L) of 6.1 (95% CI, 2.2-17.3). A subgroup analysis of hypotonic fluids with half-normal saline found a relative risk of hyponatremia of 2.42 (95% CI, 1.32-4.45).

CONCLUSION

In hospitalized children in intensive care and postoperative settings, the administration of hypotonic maintenance fluids increases the risk of hyponatremia when compared with administration of isotonic fluids. For patients on general wards, insufficient data are available based on the reviewed studies, and individual risk factors must be assessed.

Neurological symptoms in hospitalised patients: do we assess hyponatraemia with sufficient care?

AIM

To review the incidence of hyponatraemic encephalopathy in children treated in a tertiary care centre hospital, together with the clinical setting and clinical management of these cases.

METHODS

Retrospective descriptive study by chart review of patients admitted to hospital during 2000-2010. Patients older than 1 month were included who had severe hyponatraemia (sodium concentration <125 mmol/L) on admission or during their hospital stay and co-incidental neurological symptoms. Epidemiological, clinical, laboratory and therapeutic data were collected.

RESULTS

We analysed 41 cases of severe hypotonic hyponatraemia and neurological symptoms compatible with hyponatraemic encephalopathy. Boys accounted for 56.1% patients, and the median age was 1 year. Hyponatraemia was acquired in hospital by 61% of the patients, and 88% of those patients were receiving intravenous hypotonic fluids. The most frequent neurological symptom was seizures. The most common therapeutic strategy was sodium supplementation and antiepileptic drugs. Hypertonic fluids were only used in the initial treatment of 16 patients. There were two deaths related to hyponatraemic encephalopathy.

CONCLUSION

Hyponatraemia should always be considered a cause of neurological symptoms in hospitalised patients. Treatment should be prompt to prevent neurological sequelae and death. Current recommendations for fluid management in hospitalised children should be reviewed.

Isotonic versus hypotonic maintenance IV fluids in hospitalized children: a meta-analysis

OBJECTIVE

To assess evidence from randomized controlled trials (RCTs) on the safety of isotonic versus hypotonic intravenous (IV) maintenance fluids in hospitalized children.

METHODS

We searched PubMed, Embase, Cochrane Library, and clinicaltrials.gov (up to April 11, 2013) for RCTs that compared isotonic to hypotonic maintenance IV fluid therapy in hospitalized children. Relative risk (RR), weighted mean differences, and 95% confidence intervals (CIs) were calculated based on the effects on plasma sodium (pNa). The risk of developing hyponatremia (pNa <136 mmol/L), severe hyponatremia (pNa <130 mmol/L), and hypernatremia (pNa >145 mmol/L) was evaluated. We adopted a random-effects model in all meta-analyses. Sensitivity analyses by missing data were also performed.

RESULTS

Ten RCTs were included in this review. The meta-analysis showed significantly higher risk of hypotonic IV fluids for developing hyponatremia (RR 2.24, 95% CI 1.52 to 3.31) and severe hyponatremia (RR 5.29, 95% CI 1.74 to 16.06). There was a significantly greater fall in pNa in children who received hypotonic IV fluids (-3.49 mmol/L versus isotonic IV fluids, 95% CI -5.63 to -1.35). No significant difference was found between the 2 interventions in the risk of hypernatremia (RR 0.73, 95% CI 0.22 to 2.48). None of the findings was sensitive to imputation of missing data.

CONCLUSIONS

Isotonic fluids are safer than hypotonic fluids in hospitalized children requiring maintenance IV fluid therapy in terms of pNa.

Association between maintenance fluid tonicity and hospital-acquired hyponatremia

OBJECTIVE

To evaluate whether the administration of hypotonic fluids compared with isotonic fluids is associated with a greater risk for hyponatremia in hospitalized children.

STUDY DESIGN

Informatics-enabled cohort study of all hospitalizations at Lucile Packard Children's Hospital between April 2009 and March 2011. Extraction and analysis of electronic medical record data identified normonatremic hospitalized children who received either hypotonic or isotonic intravenous maintenance fluids upon admission. The primary exposure was the administration of hypotonic maintenance fluids, and the primary outcome was the development of hyponatremia (serum sodium <135 mEq/L).

RESULTS

A total of 1048 normonatremic children received either hypotonic (n = 674) or isotonic (n = 374) maintenance fluids upon admission. Hyponatremia developed in 260 (38.6%) children who received hypotonic fluids and 104 (27.8%) of those who received isotonic fluids (unadjusted OR 1.63; 95% CI 1.24-2.15, P < .001). After we controlled for intergroup differences and potential confounders, patients receiving hypotonic fluids remained more likely to develop hyponatremia (aOR 1.37, 95% CI 1.03-1.84). Multivariable analysis identified additional factors associated with the development of hyponatremia, including surgical admission (aOR 1.44, 95% CI 1.09-1.91), cardiac admitting diagnosis (aOR 2.08, 95% CI 1.34-3.20), and hematology/oncology admitting diagnosis (aOR 2.37, 95% CI 1.74-3.25).

CONCLUSIONS

Hyponatremia was common regardless of maintenance fluid tonicity; however, the administration of hypotonic maintenance fluids compared with isotonic fluids was associated with a greater risk of developing hospital-acquired hyponatremia. Additional clinical characteristics modified the hyponatremic effect of hypotonic fluid, and it is possible that optimal maintenance fluid therapy now requires a more individualized approach.

Intravenous maintenance fluids revisited

Intravenous maintenance fluid therapy aims to replace daily urinary and insensible losses for ill children in whom adequate enteric administration of fluids is contraindicated or infeasible. The traditional determination of fluid volumes and composition dates back to Holliday and Segar's seminal article from 1957, which describes the relationship between weight, energy expenditure, and physiologic losses in healthy children. Combined with estimates of daily electrolyte requirements, this information supports the use of the hypotonic maintenance fluids that were widely used in pediatric medicine. However, using hypotonic intravenous fluids in a contemporary hospitalized patient who may have complex physiologic derangements, less caloric expenditure, decreased urinary output, and elevated antidiuretic hormone levels is often not optimal; evidence over the last 2 decades shows that it may lead to an increased incidence of hyponatremia. In this review, we present the evidence for using isotonic rather than hypotonic fluids as intravenous maintenance fluid.

Hospital-acquired hyponatremia in pediatric patients: a review of the literature

Hypotonic intravenous (IV) fluids in children are a mainstay of therapy based on a recommendation made in 1957 by Holliday and Segar. Since that time, hospital-acquired hyponatremia caused by hypotonic IV fluids has been found to be an additional risk factor in the cause of death and neurological impairment in acutely ill children. This article reviews and critically evaluates the literature regarding the association of hyponatremia and hypotonic IV fluids in pediatric hospitalized, postoperative, and critical care patients.

Hypotonic versus isotonic maintenance fluids after surgery for children: a randomized controlled trial

OBJECTIVE

The objective of this randomized controlled trial was to evaluate the risk of hyponatremia following administration of a isotonic (0.9% saline) compared to a hypotonic (0.45% saline) parenteral maintenance solution (PMS) for 48 hours to postoperative pediatric patients.

METHODS

Surgical patients 6 months to 16 years of age with an expected postoperative stay of >24 hours were eligible. Patients with an uncorrected baseline plasma sodium level abnormality, hemodynamic instability, chronic diuretic use, previous enrollment, and those for whom either hypotonic PMS or isotonic PMS was considered contraindicated or necessary, were excluded. A fully blinded randomized controlled trial was performed. The primary outcome was acute hyponatremia. Secondary outcomes included severe hyponatremia, hypernatremia, adverse events attributable to acute plasma sodium level changes, and antidiuretic hormone levels.

RESULTS

A total of 258 patients were enrolled and assigned randomly to receive hypotonic PMS (N = 130) or isotonic PMS (N = 128). Baseline characteristics were similar for the 2 groups. Hypotonic PMS significantly increased the risk of hyponatremia, compared with isotonic PMS (40.8% vs 22.7%; relative risk: 1.82 [95% confidence interval: 1.21-2.74]; P = .004). Admission to the pediatric critical care unit was not an independent risk factor for the development of hyponatremia. Isotonic PMS did not increase the risk of hypernatremia (relative risk: 1.30 [95% confidence interval: 0.30-5.59]; P = .722). Antidiuretic hormone levels and adverse events were not significantly different between the groups.

CONCLUSION

Isotonic PMS is significantly safer than hypotonic PMS in protecting against acute postoperative hyponatremia in children.

A randomized controlled trial of isotonic versus hypotonic maintenance intravenous fluids in hospitalized children

Background

Isotonic saline has been proposed as a safer alternative to traditional hypotonic solutions for intravenous (IV) maintenance fluids to prevent hyponatremia. However, the optimal tonicity of maintenance intravenous fluids in hospitalized children has not been determined. The objective of this study was to estimate and compare the rates of change in serum sodium ([Na]) for patients administered either hypotonic or isotonic IV fluids for maintenance needs.

Methods

This was a masked controlled trial. Randomization was stratified by admission type: medical patients and post-operative surgical patients, aged 3 months to 18 years, who required IV fluids for at least 8 hours. Patients were randomized to receive either 0.45% or 0.9% saline in 5.0% dextrose. Treating physicians used the study fluid for maintenance; infusion rate and the use of additional fluids were left to their discretion.

Results

Sixteen children were randomized to 0.9% saline and 21 to 0.45% saline. Baseline characteristics, duration (average of 12 hours) and rate of study fluid infusion, and the volume of additional isotonic fluids given were similar for the two groups. [Na] increased significantly in the 0.9% group (+0.20 mmol/L/h [IQR +0.03, +0.4]; P = 0.02) and increased, but not significantly, in the 0.45% group (+0.08 mmol/L/h [IQR -0.15, +0.16]; P = 0.07). The rate of change and absolute change in serum [Na] did not differ significantly between groups.

Conclusions

When administered at the appropriate maintenance rate and accompanied by adequate volume expansion with isotonic fluids, 0.45% saline did not result in a drop in serum sodium during the first 12 hours of fluid therapy in children without severe baseline hyponatremia. Confirmation in a larger study is strongly recommended.

Clinical Trial Registration Number

NCT00457873 (http://www.clinicaltrials.gov/)

Hypotonic versus isotonic maintenance fluids in critically ill children: a multicenter prospective randomized study

AIM

Study the influence of hypotonic (HT) and isotonic (IT) maintenance fluids in the incidence of dysnatraemias in critically ill children.

METHODS

Prospective, randomized study conducted in three paediatric intensive care units (PICU). One hundred and twenty-five children requiring maintenance fluid therapy were included: 62 received HT fluids (50-70 mmol/L tonicity) and 63 IT fluids (156 mmol/L tonicity). Age, weight, cause of admission, sodium and fluid intake, and diuresis were collected. Blood electrolytes were measured on admission, 12 and 24 h later.

RESULTS

Blood sodium levels at 12 h were 133.7±2.7 mmol/L in HT group vs. 136.8±3.5 mmol/L in IT group (p=0.001). Adjusted for age, weight and sodium level at PICU admission, the blood sodium values of patients receiving HT fluids decrease by 3.22 mmol/L (CI: 4.29/2.15)(p=0.000). Adjusted for age, weight and hyponatraemia incidence at admission, patients receiving HT fluids increased the risk of hyponatraemia by 5.8-fold (CI: 2.4-14.0) during the study period (p=0.000).

CONCLUSIONS

Hypotonic maintenance fluids increase the incidence of hyponatraemia because they decrease blood sodium levels in normonatraemic patients. IT maintenance fluids do not increase the incidence of dysnatraemias and should be considered as the standard maintenance fluids.

The efficacy of hypotonic and near-isotonic saline for parenteral fluid therapy given at low maintenance rate in preventing significant change in plasma sodium in post-operative pediatric patients: protocol for a prospective randomized non-blinded study

BACKGROUND

Hyponatremia is the most frequent electrolyte abnormality observed in post-operative pediatric patients receiving intravenous maintenance fluid therapy. If plasma sodium concentration (p-Na+) declines to levels below 125 mmol/L in < 48 h, transient or permanent brain damage may occur. There is an intense debate as to whether the administered volume (full rate vs. restricted rate of infusion) and the composition of solutions used for parenteral maintenance fluid therapy (hypotonic vs. isotonic solutions) contribute to the development of hyponatremia. So far, there is no definitive pediatric data to support a particular choice of parenteral fluid for maintenance therapy in post-surgical patients.

METHODS/DESIGN

Our prospective randomized non-blinded study will be conducted in healthy children and adolescents aged 1 to 14 years who have been operated for acute appendicitis. Patients will be randomized either to intravenous hypotonic (0.23% or 0.40% sodium chloride in glucose, respectively) or near-isotonic (0.81% sodium chloride in glucose) solution given at approximately three-fourths of the average maintenance rate. The main outcome of interest from this study is to evaluate 24 h post-operatively whether differences in p-Na+ between treatment groups are large enough to be of clinical relevance. In addition, water and electrolyte balance as well as regulatory hormones will be measured.

DISCUSSION

This study will provide valuable information on the efficacy of hypotonic and near-isotonic fluid therapy in preventing a significant decrease in p-Na+. Finally, by means of careful electrolyte and water balance and by measuring regulatory hormones our results will also contribute to a better understanding of the physiopathology of post-operative changes in p-Na+ in a population at risk for hyponatremia.

TRIAL REGISTRATION

The protocol for this study is registered with the current controlled trials registry; registry number: ISRCTN43896775.

Intravenous fluid management for the acutely ill child

PURPOSE OF REVIEW

To review the principles of prescribing intravenous fluids (IVFs) to the acutely ill child and of adjusting sodium composition and fluid rate to prevent disorders in serum sodium or volume status from occurring.

RECENT FINDINGS

Recent data have revealed that the historic approach of administering hypotonic IVFs results in a high incidence of hospital-acquired hyponatremia in children. The majority of hospitalized children requiring IVFs are at risk for developing hyponatremia from numerous stimuli for arginine vasopressin (AVP) production, such as volume depletion, pain, stress, nausea, vomiting, respiratory or central nervous system (CNS) disorders, or the postoperative state. Multiple recent prospective studies in over 600 children have demonstrated that hypotonic fluids cause acute hyponatremia, whereas 0.9% sodium chloride (NaCl) effectively prevents it. 0.9% NaCl is the most appropriate IVF for the majority of hospitalized children. Fluid and sodium restriction will be needed for children with edematous or oliguric states and hypotonic fluids needed for children with urinary or extra-renal free water losses or hypernatremia.

SUMMARY

Hypotonic fluids should not be administered routinely in children due to the risk of hospital-acquired hyponatremia. 0.9% NaCl is the preferred IVF for the vast majority of hospitalized children.

Study of outcomes associated with hyponatremia and hypernatremia in children

Sodium is usually included in hospitals' critical values lists; however, the values at which sodium is considered to be life threatening (critical) vary among hospitals. Studies of outcomes associated with hyponatremia and hypernatremia in pediatric patients have not been published. We performed a retrospective chart review of sodium values of <124 mmol/L and >155 mmol/L that occurred during a 6-month period. Univariate and multivariate analyses for mortality risk were performed with the different variables. A total of 702 (1.32%) sodium tests fell in the study reference range, with 166 being <124 mmol/L and 536 being >155 mmol/L. Although not statistically significant, mortality was higher (38.5%) in patients with sodium values ≤ 120 mmol/L than in those with values ≥ 170 mmol/L (25%) or in patients with other values (<14%). Underlying conditions prevented assessment of morbidity associated with hyponatremia or hypernatremia. Treatment was instituted within 4 hours in 80% of cases (50% within 1 hour). Multivariate analysis showed increased risk of death for hyponatremic patients if they were premature or had heart abnormalities, while for hypernatremic patients the risk increased when other critical values were present. In conclusion, sodium levels of ≤ 120 mmol/L and ≥ 170 mmol/L have increased mortality in children; however, the risk of death is not statistically different when compared to risk in patients with milder hyponatremia and hypernatremia. Risk factors for death in hyponatremic and hypernatremic patients may primarily reflect the severity of the underlying conditions present in these children, such as prematurity and heart abnormalities, rather than the sodium derangement.

The relationship between arginine vasopressin levels and hyponatremia following a percutaneous renal biopsy in children receiving hypotonic or isotonic intravenous fluids

Post-operative hyponatremia is a common complication in children which results from hypotonic fluid administration in the presence of arginine vasopressin (AVP) excess. We evaluated the relationship between the change in serum sodium and AVP levels following percutaneous renal biopsy in children receiving either hypotonic or isotonic fluids. This study was prompted after we encountered a patient who developed near-fatal hyponatremic encephalopathy following a renal biopsy while receiving hypotonic fluids. The relationship between the change in serum sodium and AVP levels was evaluated prior to (T0) and at 5 h (T5) following a percutaneous renal biopsy in 60 children receiving either hypotonic (0.6% NaCl, 90 mEq/L) or isotonic fluids (0.9% NaCl, 154 mEq/L). The proportion of patients with elevated AVP levels post-procedure was similar between those receiving 0.6 or 0.9% NaCl (30 vs. 26%). Patients receiving 0.6% NaCl with elevated AVP levels experienced a fall in serum sodium of 1.9 ± 1.5 mEq/L, whereas those receiving 0.9% NaCl had a rise in serum sodium of 0.85 ± 0.34 mEq/L with no patients developing hyponatremia. There were no significant changes in serum sodium levels in patients with normal AVP concentrations post-procedure in either group. In conclusion, elevated AVP levels were common among our patients following a percutaneous renal biopsy. Isotonic fluids prevented a fall in serum sodium and hyponatremia, while hypotonic fluids did not.

Incidence of hyponatremia in children with gastroenteritis treated with hypotonic intravenous fluids

Hypotonic saline solutions have been used for over five decades to treat children with diarrheal dehydration. However, concern has recently been raised about the potential for iatrogenic hyponatremia as a result of this therapy. We reviewed the medical records of 531 otherwise healthy children with gastroenteritis who had been admitted to the hospital for intravenous fluid therapy. We retrospectively collected data on 141 of these children who had received two serum electrolytes (one upon admission and the other 4-24 h thereafter). The remaining 390 children were excluded because their charts lacked the required data. We analyzed data in 124 of these 141 patients whose initial serum sodium (Na) level was between 130-150 mEq/l and excluded 17 patients whose admission serum sodium fell outside this range. All patients were treated with intravenous hypotonic fluids (5% dextrose in 0.2% saline, n = 4; 5% dextrose in 0.3% saline, n = 102; 5% dextrose in 0.45% saline, n = 18 patients) as maintenance fluid therapy or maintenance fluid plus deficit therapy; 100 of these children had received an initial saline bolus of 21.05 +/- 8.5 ml/kg upon admission. The serum Na level decreased by 1.7 +/- 4.3 mEq/l in the whole group. Of the 97 children with isonatremia (Na 139.5 +/- 2.7 mEq/l) on admission, 18 (18.5%) developed mild hyponatremia (Na 133.4 +/- 0.9 mEq/l, range 131-134), with a decrease in serum Na of 5.7 +/- 3.1 mEq/l, and 79 remained isonatremic (Na 138.3 +/- 2.7 mEq/l), with a decrease in serum Na of 1.8 +/- 3.4 mEq/l (p < 0.0005). There was no significant difference in type, rate, or amount of intravenous fluid or saline bolus (26.1 +/- 10.4 vs. 20.2 +/- 8.6 ml/kg, respectively) administered in these two groups. Children who became hyponatremic were older (5.8 +/- 2.7 years) than those who remained isonatremic (2.8 +/- 3.1 years) (p < 0.0005), but there was no statistical difference in gender, degree of dehydration, and severity of metabolic acidosis between the two groups. Although serum Na increased by 3.9 +/- 2.5 mEq/l in 19 patients with mild hyponatremia upon admission (Na 132.8 +/- 1.3 to 136.7 +/- 2.6 mEq/l) and 73% of these became isonatremic, hypotonic saline solutions have the potential to cause hyponatremia in children with gastroenteritis and isonatremic dehydration.

Improving intravenous fluid therapy in children with gastroenteritis

Gastroenteritis is one of the most common medical conditions seen by pediatricians. The standard approach to intravenous fluid therapy for these children has been to administer a 0.9% sodium chloride (NaCl) bolus followed by a hypotonic solution ranging from 0.2-0.45% NaCl to replace the remaining deficit plus maintenance. We have questioned the safety of this approach as there have been reports of death or permanent neurologic impairment from hyponatremic encephalopathy. Hanna and Saberi (Pediatr Nephrol. doi: 10.1007/s00467-009-1428-y ) found the incidence of hospital-acquired hyponatremia (sodium < 135 mEq/L) to be 18.5% for patients presenting with isonatremic dehydration from gastroenteritis. This confirms that the current approach of using hypotonic fluids results in a high incidence of hyponatremia. Hypotonic fluids are not appropriate for rehydration in patients with gastroenteritis as it is a state of arginine vasopressin (AVP) excess due to both hemodynamic stimuli from volume depletion and non-hemodynamic stimuli such as nausea and vomiting. Free water will be retained until the volume deficit is corrected and the hemodynamic stimulus for AVP production abates. A safer and more effective approach is the administration of 0.9% NaCl in a continuous infusion following bolus therapy. 0.9% NaCl not only serves as prophylaxis against hyponatremia, but it is superior to hypotonic fluids as an extracellular volume expander and corrects the volume deficit more rapidly.

The impact of the National Patient Safety Agency intravenous fluid alert on iatrogenic hyponatraemia in children

In March 2007, the National Patient Safety Agency (NPSA) issued an alert regarding intravenous fluid (IVF) prescription to hospitalised infants and children, to be implemented in UK hospitals by September 2007. Previously, the most commonly used IVF (0.18% saline/4% dextrose) has been associated with iatrogenic hyponatraemia, resulting in four deaths and one near miss since 2000. The alert recommended 0.45% (or 0.9%) saline/5% dextrose as maintenance IVF and banned 0.18% saline/4% dextrose. We audited practice and outcome in children receiving maintenance IVF in June 2007 (before guideline implementation) and June 2008 (after guideline implementation). In June 2007, 44 (30%) children were prescribed IVF, six received IVF not recommended by NPSA alert 22 and one became hyponatraemic. In June 2008, 56 (30%) children received IVF; one received IVF not recommended by NPSA alert 22 and became hyponatraemic. The median change in serum sodium levels for all children who received IVF not recommended by NPSA alert 22 [-5 (-15 to 0) mmol/l] was significantly greater than those who received IVF recommended by NPSA alert 22 [0 (-13 to +7) mmol/l, p = 0.002]. In addition, there was a significant (p = 0.04) reduction in the number of children who had electrolytes checked while on IVF after implementation of the guideline. Implementation of a new IVF guideline has been associated with less use of IVF not recommended by NPSA alert 22, resulting in less serum sodium level reduction. The only children who became hyponatraemic received IVF not recommended by NPSA alert 22. Despite the NPSA alert and guideline implementation, less children had electrolyte levels checked while receiving IVF.

New aspects in the pathogenesis, prevention, and treatment of hyponatremic encephalopathy in children

Hyponatremia is the most common electrolyte abnormality encountered in children. In the past decade, new advances have been made in understanding the pathogenesis of hyponatremic encephalopathy and in its prevention and treatment. Recent data have determined that hyponatremia is a more serious condition than previously believed. It is a major comorbidity factor for a variety of illnesses, and subtle neurological findings are common. It has now become apparent that the majority of hospital-acquired hyponatremia in children is iatrogenic and due in large part to the administration of hypotonic fluids to patients with elevated arginine vasopressin levels. Recent prospective studies have demonstrated that administration of 0.9% sodium chloride in maintenance fluids can prevent the development of hyponatremia. Risk factors, such as hypoxia and central nervous system (CNS) involvement, have been identified for the development of hyponatremic encephalopathy, which can lead to neurologic injury at mildly hyponatremic values. It has also become apparent that both children and adult patients are dying from symptomatic hyponatremia due to inadequate therapy. We have proposed the use of intermittent intravenous bolus therapy with 3% sodium chloride, 2 cc/kg with a maximum of 100 cc, to rapidly reverse CNS symptoms and at the same time avoid the possibility of overcorrection of hyponatremia. In this review, we discuss how to recognize patients at risk for inadvertent overcorrection of hyponatremia and what measures should taken to prevent this, including the judicious use of 1-desamino-8d-arginine vasopressin (dDAVP).

Hospital-acquired hyponatremia in postoperative pediatric patients: prospective observational study

OBJECTIVE

To establish the incidence and factors associated with hospital-acquired hyponatremia in pediatric surgical patients who received hypotonic saline (sodium 40 mmol/L plus potassium 20 mmol/L) at the rate suggested by the Holliday and Segar's formula for calculations of maintenance fluids.

DESIGN

Prospective, observational, cohort study.

SETTING

Pediatric intensive care unit.

PATIENTS

: Eighty-one postoperative patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Incidence and factors associated with hyponatremia (sodium < or = 135 mmol/L). Univariate analysis was conducted post surgery at 12 hrs and at 24 hrs. Mean values were compared with independent t test samples. Receiver operating characteristics curve analysis was performed in variables with a p <.05, and relative risks were calculated. Eighty-one patients were included in the study. The incidence of hyponatremia at 12 hrs was 17 (21%) of 81 (95% confidence interval, 3.7-38.3); at 24 hrs, it was was 15 (31%) of 48 (95% confidence interval, 11.4-50.6). Univariate analysis at 12 hrs showed that hyponatremic patients had a higher sodium loss (0.62 mmol/kg/hr vs. 0.34 mmol/kg/hr, p = .0001), a more negative sodium balance (0.39 mmol/kg/hr vs. 0.13 mmol/kg/hr, p < .0001), and a higher diuresis (3.08 mL/kg/hr vs. 2.2 mL/kg/hr, p = .0026); relative risks were 11.55 (95% confidence interval, 2.99-44.63; p = .0004) for a sodium loss >0.5 mmol/kg/hr; 10 (95% confidence interval, 2.55-39.15; p = .0009) for a negative sodium balance >0.3 mmol/kg/hr; and 4.25 (95% confidence interval, 1.99-9.08; p = .0002) for a diuresis >3.4 mL/kg/hr. At 24 hrs, hyponatremic patients were in more positive fluid balance (0.65 mL/kg/hr vs. 0.10 mL/kg/hr, p = .0396); relative risk was 3.25 (95% confidence interval, 1.2-8.77; p = .0201), for a positive fluid balance >0.2 mL/kg/hr.

CONCLUSIONS

The incidence of hyponatremia in this population was high and progressive over time. Negative sodium balance in the first 12 postoperative hours and then a positive fluid balance could be associated with the development of postoperative hyponatremia.

Prevention of hyponatremia during maintenance intravenous fluid administration: a prospective randomized study of fluid type versus fluid rate

OBJECTIVES

To determine the importance of sodium content versus administration rate of intravenous fluids in the development of hyponatremia in postoperative children.

STUDY DESIGN

In this prospective, randomized, nonblinded study, 124 children admitted for surgery received 0.9% (NS) or 0.45% (N/2) saline solution at 100% or 50% maintenance rates. Plasma electrolytes, osmolality, and ADH at induction of anesthesia were compared with values 8 hours (T(8)), and 24 hours (T(24); n = 67) after surgery. Blood glucose and ketones were measured every 4 hours. Electrolytes and osmolality were measured in urine samples.

RESULTS

Plasma sodium concentrations fell in both N/2 groups at T(8) (100%: -1.5 +/- 2.3 mmol/L 50%: -1.9 +/- 2.0 mmol/L; P < .01) with hyponatremia more common than in the NS groups at T(8) (30% vs 10%; P = .02) but not T(24). Median plasma antidiuretic hormone concentrations increased 2- to 4-fold during surgery (P < or = .001) and only reattained levels at induction of anesthesia by T(24) in the N/2 100% group. On multiple linear regression analysis, fluid type, not rate determined risk of hyponatremia (P < .04). Two children on 100% developed SIADH (1NS). Fourteen (23%; 7NS) on 50% maintenance were assessed as dehydrated. Dextrose content was increased in 18 for hypoglycemia or ketosis.

CONCLUSIONS

The risk of hyponatremia was decreased by isotonic saline solution but not fluid restriction.

Perioperative crystalloid and colloid fluid management in children: where are we and how did we get here?

It has been more than 50 yr since the landmark article in which Holliday and Segar (Pediatrics 1957;19:823-32) proposed the rate and composition of parenteral maintenance fluids for hospitalized children. Much of our practice of fluid administration in the perioperative period is based on this article. The glucose, electrolyte, and intravascular volume requirements of the pediatric surgical patient may be quite different than the original population described, and consequently, use of traditional hypotonic fluids proposed by Holliday and Segar may cause complications, such as hyperglycemia and hyponatremia, in the postoperative surgical patient. There is significant controversy regarding the choice of isotonic versus hypotonic fluids in the postoperative period. We discuss the origins of perioperative fluid management in children, review the current options for crystalloid fluid management, and present information on colloid use in pediatric patients.