Preventing neurological complications from dysnatremias in children

Hyponatremia, hypo-osmolality, and seizures in children early post-kidney transplant

Post-transplant seizures are uncommon in young kidney transplant recipients but can be harbingers of devastating outcomes such as cerebral edema and death. We reviewed all transplants performed at our institution from January 2013 to January 2014 and compared three patients who seized within 24 h post-transplant (cases) with the remaining 33 transplant recipients (controls). Records were reviewed for hyponatremia, hypocalcemia, hypomagnesemia, BUN clearance, osmolality shifts, and blood pressure control in the first 24 h post-transplant. All cases had more pronounced (p < 0.001) shifts in serum sodium and calculated serum osmolality, with their sodium decreasing by >15 mmol/L to nadir values of 124, 131, and 131 mmol/L, respectively. There were no differences in serum calcium corrected for hypoalbuminemia, serum magnesium, urine output, or blood pressure control between the groups. Our study suggests that mild hyponatremia and an acute decrease in serum osmolality are risk factors for potentially severe postoperative neurologic complications following kidney transplantation. Thus, peri-transplant management should be optimized to anticipate and prevent these abnormalities.

Isotonic versus hypotonic saline solution for maintenance intravenous fluid therapy in children: a systematic review

BACKGROUND

The administration of hypotonic saline solution for maintenance intravenous fluid (IVF) therapy has been the standard of care, but recent evidence has shown this treatment to be associated with hyponatremia-related complications. The aim of this systematic review was to determine which IVF, i.e., a hypotonic or an isotonic saline solution, poses less risk for the development of hyponatremia among hospitalized children who require maintenance IVF therapy.

METHODS

Medline, Cochrane Library, LILACS, Current Controlled Trials, reference lists, and abstract proceedings were searched for randomized controlled trials (RCTs) comparing hypotonic and isotonic saline solutions for maintenance IVF therapy in hospitalized children. Two reviewers independently assessed all potentially relevant studies and subsequently extracted data and evaluated the methodological quality of the RCTs. Studies were then combined and analyzed using a random effects model.

RESULTS

Eleven RCTs met the inclusion criteria. Our analysis of these 11 RCTs showed that among hospitalized children receiving maintenance IVF therapy, isotonic solutions significantly decreased the risk of developing hyponatremia [relative risk (RR) 0.50, 95% confidence interval (CI) 0.40-0.62] without significantly increasing the risk for hypernatremia (RR 0.83, 95% CI 0.41-1.67).

CONCLUSIONS

Current evidence does not support the standard practice of prescribing a hypotonic saline solution as maintenance IVF therapy to hospitalized children. Although there is no single IVF composition ideal for all children, an isotonic saline solution does appear to be the safer choice when maintenance IVF therapy is used in the general pediatric population.

Isotonic intravenous maintenance fluid reduces hospital acquired hyponatremia in young children with central nervous system infections

OBJECTIVE

To find the appropriate type of intravenous fluid (isotonic vs. hypotonic saline in 5 % dextrose) for empiric maintenance fluid therapy in children with central nervous system (CNS) infections that reduces the incidence of hospital acquired hyponatremia.

METHODS

This blinded randomized controlled trial included hospitalized children aged 3 mo to 5 y with suspected CNS infections requiring intravenous maintenance fluid for at least 24 h. The subjects were randomized to receive 0.9 % saline (Group-A), 0.45 % saline (Group-B) and 0.18 % saline (Group-C) at standard maintenance rate. The outcome measures were proportion of patients developing hyponatremia (serum sodium < 135 mmol/L) after 24 h and serum sodium values at 6, 12, 18, 24 h of receiving maintenance fluids.

RESULTS

Of the 92 patients enrolled, 31, 30 and 31 patients were randomized to Group A, B and C, respectively. Majority (60.7 %) of the patients in Group-C developed hyponatremia compared with 7.1 % of the children in Group-A and 46.1 % in Group-B. During first 24 h of fluid administration successive fall in the serum sodium values was observed in patients receiving hypotonic fluids. The risk of developing hyponatremia was nearly 6½ (95 % confidence interval (CI) 1.6-26) to 8.5 (95 % CI 2.16-33.39) times more in patients who received hypotonic saline compared to those who received isotonic saline.

CONCLUSIONS

Administration of 0.9 % saline in 5 % dextrose as intravenous maintenance fluid in children with CNS infection leads to significantly less incidence of hyponatremia when compared to that with hypotonic fluids.

Isotonic versus hypotonic solutions for maintenance intravenous fluid administration in children

BACKGROUND

Maintenance intravenous fluids are frequently used in hospitalised children who cannot maintain adequate hydration through enteral intake. Traditionally used hypotonic fluids have been associated with hyponatraemia and subsequent morbidity and mortality. Use of isotonic fluid has been proposed to reduce complications.

OBJECTIVES

To establish and compare the risk of hyponatraemia by systematically reviewing studies where isotonic is compared with hypotonic intravenous fluid for maintenance purposes in children.Secondly, to compare the risk of hypernatraemia, the effect on mean serum sodium concentration and the rate of attributable adverse effects of both fluid types in children.

SEARCH METHODS

We ran the search on 17 June 2013. We searched the Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OvidSP), Embase (OvidSP), and ISI Web of Science. We also searched clinical trials registers and screened reference lists. We updated this search in October 2014 but these results have not yet been incorporated.

SELECTION CRITERIA

We included randomised controlled trials that compared isotonic versus hypotonic intravenous fluids for maintenance hydration in children.

DATA COLLECTION AND ANALYSIS

At least two authors assessed and extracted data for each trial. We presented dichotomous outcomes as risk ratios (RR) with 95% confidence intervals (CIs) and continuous outcomes as mean differences with 95% CIs.

MAIN RESULTS

Ten studies met the inclusion criteria, with a total of 1106 patients. The majority of the studies were performed in surgical or intensive care populations (or both). There was considerable variation in the composition of intravenous fluid, particularly hypotonic fluid, used in the studies. There was a low risk of bias for most of the included studies. Ten studies provided data for our primary outcome, a total of 449 patients in the analysis received isotonic fluid, while 521 received hypotonic fluid. Those who received isotonic fluid had a substantially lower risk of hyponatraemia (17% versus 34%; RR 0.48; 95% CI 0.38 to 0.60, high quality evidence). It is unclear whether there is an increased risk of hypernatraemia when isotonic fluids are used (4% versus 3%; RR 1.24; 95% CI 0.65 to 2.38, nine studies, 937 participants, low quality evidence), although the absolute number of patients developing hypernatraemia was low. Most studies had safety restrictions included in their methodology, preventing detailed investigation of serious adverse events.

AUTHORS' CONCLUSIONS

Isotonic intravenous maintenance fluids with sodium concentrations similar to that of plasma reduce the risk of hyponatraemia when compared with hypotonic intravenous fluids. These results apply for the first 24 hours of administration in a wide group of primarily surgical paediatric patients with varying severities of illness.

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.

Greater fluctuations in serum sodium levels are associated with increased mortality in children with externalized ventriculostomy drains in a PICU

OBJECTIVES

Dysnatremia is common in critically ill children due to disruption of hormonal homeostasis. Children with brain injury are at risk for syndrome of inappropriate antidiuretic hormone, cerebral salt wasting, and sodium losses due to externalized ventricular drain placement. We hypothesized that among PICU patients managed with an externalized ventricular drain, hyponatremia is common, hyponatremia is associated with seizures and in-hospital mortality, and greater sodium fluctuations are associated with in-hospital mortality.

DESIGN

Retrospective observational study.

SETTING

Tertiary care PICU.

PATIENTS

All pediatric patients treated in the PICU with an externalized ventricular drain from January 2005 to December 2009. Patients were identified by searching the physician order entry database for externalized ventricular drain orders. Hyponatremia was defined as the minimum sodium during patients' externalized ventricular drain time and was categorized as mild (131-134 mEq/L) or moderate to severe (≤ 130 mEq/L). Magnitude of sodium fluctuation was defined as the difference between a patient's highest and lowest sodium during the time in which an externalized ventricular drain was in use (up to 14 d). Seizure was defined as a clinically evident convulsion during externalized ventricular drain presence. A priori confounders were age, history of epilepsy, and externalized ventricular drain indication. Multivariable regression was performed to test the association between sodium derangements and outcomes.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Three hundred eighty patients were eligible. One hundred nine (29%) had mild hyponatremia, and 30 (8%) had moderate to severe hyponatremia. Twenty-eight patients (7%) had a seizure while hospitalized. Eighteen patients died (5%) prior to discharge. Survivors had a median daily sodium fluctuation of 1 mEq/L [0-5] vs non-survivors 9 mEq/L [6-11] (p < 0.001) and a median sodium fluctuation of 5 mEq/L [2-8] vs non-survivors 15 mEq/L [9-24] (p < 0.001) during externalized ventricular drain management. After controlling for a priori covariates and potential confounders, hyponatremia was not associated with an increased odds of seizures or in-hospital mortality. However, greater fluctuations in daily sodium (odds ratio, 1.38; 95% CI, 1.06-1.8) and greater fluctuations in sodium during externalized ventricular drain management were associated with increased odds of in-hospital mortality (odds ratio, 1.59; 95% CI, 1.2-2.11).

CONCLUSIONS

Hyponatremia was common in PICU patients treated with externalized ventricular drains but not associated with seizures or in-hospital mortality. Greater sodium fluctuations during externalized ventricular drain management were independently associated with increased odds of in-hospital mortality.

Electrolyte disorders

Electrolyte disorders can result in life-threatening complications. The kidneys are tasked with maintaining electrolyte homoeostasis, yet the low glomerular filtration rate of neonatal kidneys, tubular immaturity, and high extrarenal fluid losses contribute to increased occurrence of electrolyte disorders in neonates. Understanding the physiologic basis of renal electrolyte handling is crucial in identifying underlying causes and initiation of proper treatment. This article reviews key aspects of renal physiology, the diagnostic workup of disorders of plasma sodium and potassium, and the appropriate treatment, in addition to inherited disorders associated with neonatal electrolyte disturbances that illuminate the physiology of renal electrolyte handling.

Neonatal endocrine emergencies: a primer for the emergency physician

The resuscitation principles of securing the airway and stabilizing hemodynamics remain the same in any neonatal emergency. However, stabilizing endocrine disorders may prove especially challenging. Several organ systems are affected simultaneously and the clinical presentation can be subtle. Although not all-inclusive, the implementation of newborn screening tests has significantly reduced morbidity and mortality in neonates. Implementing routine screening tests worldwide and improving the accuracy of present tests remains the challenge for healthcare providers. With further study of these disorders and best treatment practices we can provide neonates presenting to the emergency department with the best possible outcomes.

Disorders of sodium and water balance

Dysnatremias occur simultaneously with disorders in water balance. The first priority is to correct dehydration; once the patient is euvolemic, the sodium level can be reassessed. In unstable patients with hyponatremia, the clinician should rapidly administer hypertonic saline. In unstable patients with hypernatremia, the clinician should administer isotonic intravenous fluid. In stable patients with either hyponatremia or hypernatremia, the clinician should aim for correction over 24 to 48 hours, with the maximal change in serum sodium between 8 to 12 mEq/L over the first 24 hours. This rate of correction decreases the chances of cerebral edema or osmotic demyelination syndrome.

Hypotonic solution decreases serum sodium in infants with moderate bronchiolitis

AIM

To investigate the influence of hypotonic parenteral hydration on serum and urinary sodium and osmolality in infants with moderate bronchiolitis.

METHODS

We studied 36 infants (mean age 3.7 ± 2.3 months), with a diagnosis of moderate bronchiolitis admitted to a paediatric emergency unit in São Paulo, Brazil. Patients received a standard parenteral hypotonic solution, according to Holliday and Segar, during the first 24 h, due to respiratory distress. The disease was monitored by a respiratory severity score (RDAI-Respiratory Distress Assessment Instrument), respiratory rate and oxygen saturation. Serum and urinary sodium and osmolality were monitored at admission, 24 and 48 h after admission.

RESULTS

All respiratory parameters improved during hospitalisation. Serum sodium and osmolality dropped after 24 h (136.8 ± 2.8 and 135.8 ± 2.6 mEq/L, p = 0.031; 283.4 ± 4.1 and 281.6 ± 3.9 mOsm/kg, p = 0.004 respectively) as well as urinary osmolality (486.8 ± 243.4 mOsm/kg and 355.7 ± 205.0 mOsm/kg, p < 0.001) when compared to admission.

CONCLUSION

This study reinforces the occurrence of hyponatraemia in bronchiolitis even in patients with moderate disease and highlights the risk of serum sodium drop caused by hypotonic parenteral hydration.

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.

Fluid management in the critically ill child

Fluid management has a major impact on the duration, severity and outcome of critical illness. The overall strategy for the acutely ill child should be biphasic. Aggressive volume expansion to support tissue oxygen delivery as part of early goal-directed resuscitation algorithms for shock--especially septic shock--has been associated with dramatic improvements in outcome. Recent data suggest that the cost-benefit of aggressive fluid resuscitation may be more complex than previously thought, and may depend on case-mix and the availability of intensive care. After the resuscitation phase, critically ill children tend to retain free water while having reduced insensible losses. Fluid regimens that limit or avoid positive fluid balance are associated with a reduced length of hospital stay and fewer complications. Identifying the point at which patients change from the 'early shock' pattern to the later 'chronic critical illness' pattern remains a major challenge. Very little data are available on the choice of fluids, and most of the information that is available arises from studies of critically ill adults. There is therefore an urgent need for high-quality trials of both resuscitation and maintenance fluid regimens in critically ill children.

Case studies in fluid and electrolyte therapy

Disorders in serum sodium, hyponatremia and hypernatremia, are frequently encountered in both inpatient and outpatient settings. Many sodium disorders are iatrogenic, caused by inappropriate intravenous fluid management. The methods of prevention and treatment of serum disorders differ based on the underlying disease states. Nine cases are presented to illustrate different aspects of fluid management, with an emphasis on the prevention and treatment of disorders in serum sodium. Key concepts that are discussed are (1) when to use an isotonic fluid versus a hypotonic fluid, (2) when to restrict or liberalize maintenance intravenous fluids, (3) how to use 3% sodium chloride for the treatment of hyponatremic encephalopathy, (4) when to use desmospressin to prevent the overcorrection of chronic hyponatremia, and (5) strategies to treat different causes of hypernatremic dehydration in children.

What is the safe approach for neonatal hypernatremic dehydration? A retrospective study from a neonatal intensive care unit

OBJECTIVES

The aims of this study were to evaluate the prevalence, complications, and mortality of hypernatremic dehydration in neonates and to compare the effect of correction rate at 48 hours on mortality and on neurological outcome in the short term.

METHODS

This retrospective study was conducted between January 2007 and 2011 in the neonatal intensive care unit. Term neonates were included. The patients were grouped as follows: group 1 = 150 to 160 mmol/L, group 2 = 161 to 170 mmol/L and group 3 = 171 to 189 mmol/L.

RESULTS

Among 4280 neonates, 81 cases (1.8%) had hypernatremic dehydration. Groups 1, 2, and 3 consisted of 55, 23, and 3 patients, respectively. Mortality rates were as follows: 3.6%, 17.3%, and 66.6%. Mean serum sodium (Na) correction rates at 0 to 24 hours and 24 to 48 hours were 0.48 ± 0.2 versus 0.38 ± 0.31 mmol/L per hour (group 1) and 0.49 ± 0.21 versus 0.52 ± 0.28 mmol/L per hour (group 2), respectively. In 32 patients (58.1%) from group 1 and in 13 patients (56.5%) from group 2, correction rate of 0.5 mmol/L per hour or less was achieved. Twenty-two patients developed convulsions, which was the most common complication during therapy. Serum Na greater than 160 mmol/L at admission (odds ratio, 1.9; 95% confidence interval, 1.3-3.7) and serum Na correction rate of greater than 0.5 mmol/L per hour (odds ratio, 4.3; 95% confidence interval, 1.2-6.5) were independent risk factors for death or convulsion. There was a significant difference between groups 1 and 2 in Denver Developmental Screening Test II results (64.1% vs 30.7 %, P = 0.001).

CONCLUSION

Hypernatremic dehydration is an important problem that should be managed properly to avoid adverse outcomes.

Clinical review: practical approach to hyponatraemia and hypernatraemia in critically ill patients

Disturbances in sodium concentration are common in the critically ill patient and associated with increased mortality. The key principle in treatment and prevention is that plasma [Na+] (P-[Na+]) is determined by external water and cation balances. P-[Na+] determines plasma tonicity. An important exception is hyperglycaemia, where P-[Na+] may be reduced despite plasma hypertonicity. The patient is first treated to secure airway, breathing and circulation to diminish secondary organ damage. Symptoms are critical when handling a patient with hyponatraemia. Severe symptoms are treated with 2 ml/kg 3% NaCl bolus infusions irrespective of the supposed duration of hyponatraemia. The goal is to reduce cerebral symptoms. The bolus therapy ensures an immediate and controllable rise in P-[Na+]. A maximum of three boluses are given (increases P-[Na+] about 6 mmol/l). In all patients with hyponatraemia, correction above 10 mmol/l/day must be avoided to reduce the risk of osmotic demyelination. Practical measures for handling a rapid rise in P-[Na+] are discussed. The risk of overcorrection is associated with the mechanisms that cause hyponatraemia. Traditional classifications according to volume status are notoriously difficult to handle in clinical practice. Moreover, multiple combined mechanisms are common. More than one mechanism must therefore be considered for safe and lasting correction. Hypernatraemia is less common than hyponatraemia, but implies that the patient is more ill and has a worse prognosis. A practical approach includes treatment of the underlying diseases and restoration of the distorted water and salt balances. Multiple combined mechanisms are common and must be searched for. Importantly, hypernatraemia is not only a matter of water deficit, and treatment of the critically ill patient with an accumulated fluid balance of 20 litres and corresponding weight gain should not comprise more water, but measures to invoke a negative cation balance. Reduction of hypernatraemia/hypertonicity is critical, but should not exceed 12 mmol/l/day in order to reduce the risk of rebounding brain oedema.

Maintenance intravenous fluid prescribing practices among paediatric residents

AIM

  To investigate the sodium composition of maintenance intravenous fluids (mIVF) used by paediatric residents throughout the United States in common clinical scenarios of arginine vasopressin (AVP) excess.

METHODS

  We distributed an online survey to paediatric residency programmes asking what type of mIVF (0.2%, 0.45%, 0.9% NaCl or lactated Ringer's solution) they would administer in four common clinical scenarios of AVP excess (gastroenteritis, pneumonia, meningitis and postoperative) in both a 6-month-old (mo) and a 13-year-old (yo) child.

RESULTS

  We had 472 responses, representing 5% of the total paediatric residency population in the United States. Hypotonic mIVF were selected in 78% of children (88.2% of 6 mo and 68.5% of 13 yo). Isotonic mIVF were selected approximately twice as often for patients with meningitis as for those without (21.4% vs. 8.7% 6 mo and 42.8% vs. 27.7% 13 yo; p < 0.001).

CONCLUSIONS

  The majority of US paediatric residents would prescribe hypotonic mIVF in disease states associated with AVP excess. However, a significant number of residents are using isotonic mIVF. Isotonic fluids are more likely to be prescribed in older children and children with meningitis.

Isotonic versus hypotonic fluid supplementation in term neonates with severe hyperbilirubinemia - a double-blind, randomized, controlled trial

AIM

To compare the incidence of hyponatremia in full-term neonates with severe hyperbilirubinemia, receiving intravenous fluid supplementation with 0.2% saline in 5% dextrose versus 0.9% saline in 5% dextrose, to prevent blood exchange transfusion (BET).

METHODS

In this double-blind, randomized, controlled trial, full-term newborns (≥37 weeks), appropriate for gestational age, with severe non-haemolytic hyperbilirubinemia (serum bilirubin ≥ 20 mg/dL) were enrolled. Eligible neonates were randomized to receive either 0.2% saline in 5% dextrose (hypotonic fluid group) or 0.9% saline in 5% dextrose (isotonic fluid group) over 8 hrs, in addition to phototherapy. The primary outcome was proportion of neonates developing hyponatremia (serum Na < 135 mmol/L) after 8 h.

RESULTS

Forty-two neonates were analysed in each group. Proportion of neonates developing hyponatremia after 8 h was higher in hypotonic fluid group as compared to isotonic fluid group (48.8% vs. 10.5%, p < 0.001). However, a larger proportion in isotonic fluid group developed hypernatremia (39.5% vs. 12.2%, p < 0.001). The rate of BET was similar in both groups.

CONCLUSION

In full-term neonates with severe hyperbilirubinemia, administration of hypotonic fluid to prevent BET was associated with a higher incidence of hyponatremia while isotonic fluid was associated with an increased incidence of hypernatremia.

Neonatal hyponatremia: differential diagnosis and treatment

Hyponatremia is very frequent in neonates, especially in VLBW. Recent data have shown that hyponatremia is not so benign as previously believed,and several clinical studies have indicated that preterms with mild to moderate chronic hyponatremia may experience poor growth and development retardation. The aim of this review is to present how to differentiate hypovolemic, euvolemic and hypervolemic hypernatremias, suggesting algorithms for practical management.

Normal saline is a safe initial rehydration fluid in children with diarrhea-related hypernatremia

To demonstrate safety and efficacy of using normal saline (NS) for initial volume expansion (IVE) and rehydration in children with diarrhea-related hypernatremic dehydration (DR-HD), forty eight patients with DR-HD were retrospectively studied. NS was used as needed for IVE and for initial rehydration. Fluid deficit was given over 48 h. Median Na(+) level on admission was 162.9 mEq/L (IQR 160.8-165.8). The median average hourly drop at 6 and 24 h was 0.53 mEq/L/h (0.48-0.59) and 0.52 mEq/L/h (0.47-0.57), respectively. Compared to children not needing IVE, receiving ≥40 ml/kg IVE was associated with a higher average hourly drop of Na(+) at 6 h (0.51 vs. 0.58 mEq/L/h, p = 0.013) but not at 24 h (p = 0.663). The three patients (6.3%) with seizures had a higher average hourly drop of Na(+) at 6 and 24 h (p = 0.084 and 0.021, respectively). Mortality (4/48, 8.3%) was not related to Na(+) on admission or to its average hourly drop at 6 or 24 h. Children receiving ≥40 ml/kg IVE were more likely to die (OR 3.3; CI, 1.5-7.2).

CONCLUSION

In children with DR-HD, NS is a safe rehydration fluid with a satisfactory rate of Na(+) drop and relatively low incidence of morbidity and mortality. Judicious use of IVE should be exerted and closer monitoring should be guaranteed for children requiring large volumes for IVE and for those showing rapid initial drop of serum Na(+) to avoid neurological complications and poor outcome.

European consensus statement for intraoperative fluid therapy in children

The intraoperative infusion of isotonic solutions with 1-2.5% glucose in children is considered well established use in Europe and other countries. Unfortunately, a European marketing authorisation of such a solution is currently missing and as a consequence paediatric anaesthetists tend to use suboptimal intravenous fluid strategies that may lead to serious morbidity and even mortality because of iatrogenic hyponatraemia, hyperglycaemia or medical errors. To address this issue, the German Scientific Working Group for Paediatric Anaesthesia suggests a European consensus statement on the composition of an appropriate intraoperative solution for infusion in children, which was discussed during a working session at the 2nd Congress of the European Society for Paediatric Anaesthesiology in Berlin in September 2010. As a result, it was recommended that an intraoperative fluid should have an osmolarity close to the physiologic range in children in order to avoid hyponatraemia, an addition of 1-2.5% instead of 5% glucose in order to avoid hypoglycaemia, lipolysis or hyperglycaemia and should also include metabolic anions (i.e. acetate, lactate or malate) as bicarbonate precursors to prevent hyperchloraemic acidosis. Thus, the underlying intention of this consensus statement is to facilitate the granting of a European marketing authorisation for such a solution with the ultimate goal of improving the safety and effectiveness of intraoperative fluid therapy in children.

Three-percent saline administration during pediatric critical care transport

OBJECTIVES

The purpose of this study was to describe the administration of 3% saline (3%S) during pediatric critical care transport.

METHODS

A retrospective study was performed on pediatric patients who underwent critical transport to Loma Linda University Children's Hospital from January 1, 2003, to June 30, 2007, and were given 3%S. Patients' demographics, admission diagnosis, route and amount of 3%S administration, serum electrolytes, vital signs, radiographic data, and Glasgow Coma Scale scores were collected and analyzed.

RESULTS

A total of 101 children who received 3%S infusions during pediatric critical care transport were identified. Mean patient age was 5.9 years, and mean patient weight was 27.6 kg. The main indications for infusing 3%S were suspected cerebral edema (41%), intracranial bleed with edema (51%), and symptomatic hyponatremia (6%). The amount of 3%S bolus ranged from 1.2 to 24 mL/kg, with a mean of 5.4 mL/kg. Serum electrolytes before and after 3%S infusion demonstrated significant increases in sodium, chloride, and bicarbonate levels (P < 0.05). A significant reduction was also seen in serum urea nitrogen levels and anion gap. Radiographic imaging performed before 3%S infusion demonstrated findings consistent with concerns of increased intracranial pressure such as intracranial bleed and cerebral edema. The route of initial 3%S infusions was mainly through peripheral intravenous lines (96%). No complications related to the 3%S delivery such as local reactions, renal abnormalities, or central pontine myelinolysis were observed.

CONCLUSIONS

It seems 3%S may be administered safely during pediatric critical transport and administration routes can include peripheral lines. With the importance of initiating therapy early to improve patient outcomes, the use of 3%S may benefit transported children with brain injury and suspected intracranial hypertension.

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/)

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.

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.

Body fluids and salt metabolism - part II

There is a high frequency of diarrhea and vomiting in childhood. As a consequence the focus of the present review is to recognize the different body fluid compartments, to clinically assess the degree of dehydration, to know how the equilibrium between extracellular fluid and intracellular fluid is maintained, to calculate the effective blood osmolality and discuss both parenteral fluid maintenance and replacement.

A novel isotonic-balanced electrolyte solution with 1% glucose for intraoperative fluid therapy in children: results of a prospective multicentre observational post-authorization safety study (PASS)

BACKGROUND

The recommendations for intraoperative fluid therapy in children have been adapted from hypotonic to isotonic electrolyte solutions with lower glucose concentrations (1-2.5% instead of 5%) to avoid hyponatremia and hyperglycemia.

OBJECTIVE

The objective of this prospective multicentre observational post-authorization safety study was to evaluate the intraoperative use of a novel isotonic-balanced electrolyte solution with 1% glucose (BS-G1) with a particular focus on changes in acid-base status, electrolyte and glucose concentrations.

METHODS

Following local ethics committee approval, pediatric patients aged up to 4 years with an ASA risk score of I-III undergoing intraoperative administration of BS-G1 were enrolled. Patient demographics, the performed procedure, adverse drug reactions, hemodynamic data, and the results of blood gas analysis before and after infusion were documented with a focus on changes in acid-base status, electrolyte and glucose concentrations.

RESULTS

In 107 patients (ASA I-III; age 16.2 ± 15.4, range day of birth to 47.7 months; body weight 8.8 ± 4.8, range 1.6-18.8 kg), the mean volume infused was 20 ± 12.6 (range 3.6-83.3) ml·kg(-1) BS-G1. During the infusion, hemoglobin, hematocrit, anion gap, strong ion difference, and calcium decreased and chloride and glucose increased significantly within the physiologic range. All other measured parameters including sodium, bicarbonate, base excess, and lactate remained stable. Neither hypoglycemia (glucose <2.5 mmol·l(-1) ) nor hyperglycemia (glucose >10 mmol·l(-1) ) was documented after BS-G1 infusion. No adverse drug reactions were reported.

CONCLUSION

The studied isotonic-balanced electrolyte solution with 1% glucose helps to avoid perioperative acid-base imbalance, hyponatremia, hyperglycemia, and ketoacidosis in infants and toddlers and may therefore enhance patient safety.

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.

100 cc 3% sodium chloride bolus: a novel treatment for hyponatremic encephalopathy

Hyponatremic encephalopathy is a potentially lethal condition with numerous reports of death or permanent neurological injury. The optimal treatment for hyponatremic encephalopathy remains controversial. We have introduced a unified approach to the treatment of hyponatremic encephalopathy which uses 3% NaCl (513 mEq/L) bolus therapy. Any patient with suspected hyponatremic encephalopathy should receive a 2 cc/kg bolus of 3% NaCl with a maximum of 100 cc, which could be repeated 1-2 times if symptoms persist. The approach results in a controlled and immediate rise in serum sodium with little risk of inadvertent overcorrection.

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.

The use of isotonic fluid as maintenance therapy prevents iatrogenic hyponatremia in pediatrics: a randomized, controlled open study

OBJECTIVES

Hypotonic fluids are widely used in pediatrics. Several articles have reported the risk of iatrogenic hyponatremia secondary to this practice. We primarily intend to determine whether the use of isotonic fluids prevents hyponatremia and, secondly, whether these fluids increase the incidence of adverse events.

STUDY DESIGN

One hundred twenty-two pediatric patients hospitalized in intensive care unit requiring maintenance fluid therapy were randomized to receive isotonic fluids (isotonic group, NaCl = 140 mEq/L) or hypotonic fluids (hypotonic group, NaCl <100 mEq/L). Electrolyte blood concentration, glycaemia, and blood pressure were measured at 0, 6, and 24 hrs after the beginning of fluid therapy. Plasma creatinine, urine specific gravity, and urine electrolyte concentration were measured at 6 hrs. Standard intention-to-treat analysis and Bayesian analysis were conducted to assess the probability of hyponatremia and hypernatremia in each group.

RESULTS

At the time of admission to hospital, no differences in natremia or the percentage of hyponatremia were found between groups. At 24 hrs, the percentage of hyponatremia in the hypotonic group was 20.6% as opposed to 5.1% in the isotonic group (p = 0.02). No differences in the number of adverse events other than hyponatremia were observed between groups.

CONCLUSIONS

The use of hypotonic fluids increases the risk of hyponatremia when compared with isotonic fluids at 24 hrs following infusion (number needed to harm [confidence interval 95%] = 7[4;25]). In our sample, the use of isotonic fluids did not increase the incidence of adverse events compared with hypotonic fluids.

An audit of intravenous fluid prescribing and plasma electrolyte monitoring; a comparison with guidelines from the National Patient Safety Agency

OBJECTIVES

To audit past practice of intravenous (i.v.) fluid prescribing and electrolyte monitoring, prior to the publication of guidelines by the National Patient Safety Agency (NPSA, Ref. NPSA/2007/22) in March 2007, highlighting areas of discrepancy, in a specialist children's hospital.

METHODS

We performed a retrospective case note review of 100 appendectomy patients between February 2004 and March 2007, recording; fluid type and volumes given as maintenance therapy, resuscitation boluses and nasogastric replacement; the frequency and timing of plasma electrolyte measurement; the relationship between plasma sodium [Na] concentration and i.v. fluid prescribed; and patient weight recordings.

RESULTS

Ninety-eight acute appendectomies and two interval elective appendectomies. Median age 10 years (interquartile range: 8-11.25). Before surgery, hypotonic maintenance fluid was prescribed for 94% patients. During surgery, maintenance fluid was predominantly isotonic. After surgery, hypotonic maintenance fluid was prescribed for 92% patients. All maintenance fluid volumes were appropriately calculated according to weight using the Holliday and Segar formula (Paediatrics, 19, 1957, 823). Fluid boluses were isotonic on 128/129 occasions and all accurately calculated according to weight. Nasogastric losses were replaced with 0.9% sodium chloride. No patient had daily plasma electrolyte measurements whilst administered i.v. fluid. Twenty-seven patients had recorded hyponatremia ([Na] <135 mmol x l(-1); 21 at presentation, six subsequently after admission). Hypotonic maintenance fluid was continued in 26/27 patients with hyponatremia. No patient had daily weight recorded.

CONCLUSIONS

Our practice of i.v. fluid prescribing and electrolyte monitoring in children, prior to the publication of guidelines by the NPSA in March 2007, did not fully meet the recommended standards.

[Water-electrolyte abnormalities during pregnancy: maternal and fetal complications (about a case)]

Water-electrolyte abnormalities while pregnancy or for infant are very serious. We present a case of a woman at 26 weeks who had gestation pernicious vomiting that led to major extracellular dehydration, water intoxication and acute renal insufficiency. The etiology was a volvulus on common mesentery. Hyperemesis disappeared thanks to surgical treatment. The mother and her fetus would later present serious complications due to the water-electrolyte imbalance correction. The fetus suffered from cerebral hemorrhage and subdural hematoma subordinate to brain edema resorption. The mother presented centropontine myelinolysis. The treatment of electrolyte abnormalities during pregnancy could lead to serious complications for the mother and fatal for the foetus.

Maintenance fluid therapy: what it is and what it is not

Fifty years after the publication of a prescription for maintenance fluid therapy, concerns have been raised about the use of hypotonic fluids in hospitalized children. We discuss what maintenance fluid therapy is or what it is not; where maintenance fluid therapy has been misused. We also discuss concerns with the immediate adoption of isotonic fluid as maintenance fluid without careful consideration and testing.

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

OBJECTIVE

To determine the incidence and clinical consequences of postoperative hyponatremia in children.

STUDY DESIGN

We performed a retrospective analysis of postoperative admissions to the pediatric intensive care unit (excluding cardiac, neurosurgical, and renal). The incidence of severe (serum sodium < 125 mmol/L or symptoms) and moderate (serum sodium < 130 mmol/L) hyponatremia in children receiving hypotonic (HT) and normotonic (NT) fluids was calculated.

RESULTS

Out of a total of 145 children (568 sodium measurements; 116 HT and 29 NT), we identified 16 with hyponatremia (11%). The incidences of moderate (10.3% vs 3.4%, P = .258) and severe (2.6% vs 0%; P = .881) hyponatremia were not significantly different in the HT and NT groups. There were no neurologic sequelae or deaths related to hyponatremia.

CONCLUSIONS

In our study group, hyponatremia was common, but morbidity and death were not observed. Careful monitoring of serum sodium level may be responsible for this lack of adverse outcomes. Larger, prospective studies are needed to determine whether the incidence of hyponatremia differs between the HT and NT groups.