Perioperative infusions in paediatric patients: rationale for using Ringer-lactate solution with low dextrose concentration

Glycaemic profile of children undergoing anaesthesia (GLYCANA) at Mercy James Centre in Malawi: an observational study

BACKGROUND

Hypoglycaemia and hyperglycaemia may develop during anaesthesia and surgery in children and can lead to severe adverse clinical outcomes. No study, as far as we know, has investigated glucose homeostasis in children undergoing surgery in Malawi. The aim of this study was to assess perioperative glucose levels of the children undergoing anaesthesia at Mercy James Centre (MJC) for Paediatric Surgery, Blantyre, Malawi.

METHODOLOGY

This was an observational cross-sectional study. We looked at 100 children aged 1 day to 15 years anaesthetised at MJC. Data were analysed using SPSS 28. Student t test and Analysis of the variance (ANOVA) were used to compare means. The level of significance was 5%.

RESULTS

Male children represented 68%. The median age was 2.2 years. Sixten percents of patient were underweight. Fasting times were prolonged for 87%. Maintenance IV fluid with 2.5% dextrose was given to 14%. Overall, there was a significant increase of glycaemia from induction of anaesthesia to the end of the procedure. Hypoglycaemia was rare. The mean fasting glycaemia was 99.04 mg/dL ± 1.8, 116.95 mg/dL ± 34.2 at 30 min into the procedure and 127.62 mg/dL ± 46.8 at the end of the procedure. The differences in means were statistically significant (p < 0.001). Prolonged fasting times was associated with lower blood glucose means whereas nutrition status, type of the procedure, addition of dextrose in the fluid, and duration of procedure were associated with higher glycaemia means.

CONCLUSION

Glycaemia increases under anaesthesia and surgery. Recommended fasting times, optimising nutritional status, when possible, no dextrose or lower than 2.5% dextrose in IV maintenance fluid are possible strategies to maintain blood sugar homeostasis during paediatric surgery and anaesthesia.

Intermittent boluses of balanced salt solution for post-operative intravenous hydration following elective major abdominal and thoracic surgery in children

PURPOSE

Maintenance fluids following major operations in children are typically administered with a continuous rate. We hypothesized that administering fluids as intermittent boluses is more physiologic and could limit post-operative fluid volume, thereby avoiding harmful effects of excess fluid.

METHODS

We retrospectively reviewed children aged 1-21 admitted after an elective major abdominal or thoracic operation from 2015 to 2021. We excluded non-elective operations and patients receiving peri-operative enteral or parenteral nutrition. We analyzed total fluid volume at 0-24, 24-48, 48-72, and 72-96 h, time to regular diet and discharge, and end-organ complications.

RESULTS

We identified 363 patients, of which 108 received intermittent boluses and 255 continuous fluids. Bolus group patients received significantly less fluid up to 72 h post-operatively with average rates of 0.49 mL/kg/h vs 0.86 mL/kg/h at 0-24 h (p << 0.01), 0.57 mL/kg/h vs 1.46 mL/kg/h at 24-48 h (p << 0.01), and 0.50 vs 0.92 mL/kg/h at 48-72 h (p << 0.01). Additionally, the bolus group maintained adequate urine output, tolerated a regular diet sooner (2.08 days vs 2.51 days; p = 0.0023) and averaged a shorter hospital stay (3.12 vs 4.14 days; p = 0.004). There was no difference in adverse effects between the two groups.

CONCLUSION

Utilizing intermittent boluses reduces the volume of maintenance fluids administered and may lead to a faster time to regular diet and discharge.

LEVEL OF EVIDENCE

IV.

TYPE OF STUDY

Retrospective review.

Risks of severe hyponatremia in children receiving hypotonic fluids

Intravenous fluids are frequently used in hospitalized children. Hypotonic fluids have been the standard of care in pediatrics for many years. This might be explained by the empiricism of early recommendations favoring fluids with dextrose, but an insufficient amount of sodium. The risk of hyponatremia (<135mmol/L) might be increased by the occurrence of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in the course of common acute diseases (e.g., bronchiolitis, acute gastroenteritis, encephalitis, meningitis) in children. Severe hyponatremia (<130mmol/L) is often associated with neurologic complications leading to sequelae or even death. Over the last few years, hyponatremia induced by hypotonic fluids has been increasingly reported, and significant progress has been made in the understanding of cerebral edema and osmotic demyelination. Several randomized clinical trials have shown weak but significant evidence that isotonic fluids were superior to hypotonic solutions in preventing hyponatremia. However, clinical practices have not changed much in France, as suggested by the analysis of intravenous fluids ordered from the Assistance Publique-Hôpitaux de Paris (AP-HP) central pharmacy (PCH) in 2017. Therefore, it would be advisable that national guidelines be released under the French Health Authorities regarding the safe infusion of infants and children.

Comparison of Intraoperative Glycemic Levels in Infants with the Use of Ringer Lactate with Supplemental 1% versus 2% Dextrose as Maintenance Fluid

Context

There is no consensus regarding the concentration of dextrose supplementation to be used in pediatric patients intraoperatively.

Aims

The primary objective was to assess the effect of using Ringer lactate (RL) with 1% versus 2% dextrose as maintenance fluid in infants on intraoperative blood glucose levels. The secondary objectives included assessment of incidence of hyperglycemia and hypoglycemia in both groups.

Settings and Design

This was a prospective randomized study conducted in a tertiary care teaching institute.

Subjects and Methods

Forty infants undergoing cheiloplasty or palatoplasty were included. All patients fasted 6 h for solids and formula feeds, 4 h for breast milk, and 2 h for clear fluids and received general anesthesia as per standardized protocol. Patients belonging to Group 1 received RL with 1% dextrose supplementation, whereas Group 2 received RL with 2% dextrose added to it as an intraoperative maintenance fluid. Random blood sugar (RBS) was checked preoperatively and then at 60 min and 120 min after induction. Hypoglycemia was defined as RBS <70 mg/dL and hyperglycemia as RBS >150 mg/dL.

Statistical Analysis Used

Independent sample ttest and Pearson's Chisquare test were used for statistical analysis.

Results

Preoperative RBS was comparable in both groups. RBS at 60 and 120 min was significantly higher in Group 2 compared to Group 1. There was no incidence of hypoglycemia in both groups, and the incidence of hyperglycemia was similar in both groups.

Conclusion

Use of RL with 2% dextrose as intraoperative maintenance fluid in infants resulted in significant increase in blood sugar levels as compared to addition of 1% dextrose although the incidence of hyperglycemia remained comparable in both groups.

Perioperative fluid management in children: can we sum it all up now?

PURPOSE OF REVIEW

The composition and type of intravenous fluids during paediatric anaesthesia have been subjects of debates for decades. Errors in perioperative fluid management in children may lead to serious complications and a negative outcome. Therefore, in this review, historical and recent developments and recommendations for perioperative fluid management in children are presented, based on physiology and focused on safety and efficacy.

RECENT FINDINGS

Optimized fasting times and liberal clear fluid intake until 1 h improve patient comfort and metabolic and haemodynamic condition after induction of anaesthesia. Physiologically composed balanced isotonic electrolyte solutions are safer than hypotonic electrolyte solutions or saline 0.9% to protect young children against the risks of hyponatraemia and hyperchloraemic acidosis. For intraoperative maintenance infusion, addition of 1-2% glucose is sufficient to avoid hypoglycaemia, lipolysis or hyperglycaemia. Modified fluid gelatine or hydroxyethyl starch in balanced electrolyte solution can safely be used to quickly normalize blood volume in case of perioperative circulatory instability and blood loss.

SUMMARY

Physiologically composed balanced isotonic electrolyte solutions are beneficial for maintaining homeostasis, shifting the status more towards the normal range in patients with preexisting imbalances and have a wide margin of safety in case of accidental hyperinfusion.

Effect of Using Ringer's Lactate, with and without Addition of Dextrose, on Intra-Operative Blood Sugar Levels in Infants Undergoing Facial Cleft Surgeries

Background:

Addition of glucose in the intraoperative fluid is a routine practice in infants. Under general anesthesia, due to neuroendocrine stress response, this could result in overt hyperglycemia.

Aims:

The aim of this study was to find whether the addition of 2% dextrose to Ringer's lactate (RL) caused hyperglycemia compared to no addition of dextrose to RL.

Settings and Designs:

This prospective randomized study was conducted in 100 infants undergoing facial cleft surgery at a tertiary care institution.

Subjects and Methods:

Group D received RL with 2% dextrose and Group R received RL without the addition of dextrose. Blood sugars were measured at induction, 1 h and 2 h later. Hyperglycemia was defined as blood sugar >150 mg/dL and hypoglycemia as <70 mg/dL.

Statistical Analysis Used:

Pearson's Chi-square test, Paired t-test, Mann–Whitney test, and Independent sample t-test were used as applicable.

Results:

Baseline blood sugar was comparable in both groups. A significant increase in blood sugar values from baseline was seen in both groups, but the increase was significantly more in Group D at 60 min (136.5 ± 41.9 vs. 109.2 ± 20.5) and at 120 min (150.1 ± 45.5 vs. 123.1 ± 31.7). The incidence of hyperglycemia was 50% in Group D and 12% in Group R. No patient developed hypoglycemia intraoperatively. No significant correlation between blood sugar and hours of fasting was established.

Conclusion:

Routine addition of dextrose to RL is not essential during short surgeries under general anesthesia in infants, provided preinduction blood sugar level is >70 mg/dL and intraoperative sugars are periodically monitored.

Choosing Wisely in pediatric anesthesia: An interpretation from the German Scientific Working Group of Paediatric Anaesthesia (WAKKA)

Inspired by the Choosing Wisely initiative, a group of pediatric anesthesiologists representing the German Working Group on Paediatric Anaesthesia (WAKKA) coined and agreed upon 10 concise positive ("dos") or negative ("don'ts") evidence-based recommendations. (i) In infants and children with robust indications for surgical, interventional, or diagnostic procedures, anesthesia or sedation should not be avoided or delayed due to the potential neurotoxicity associated with the exposure to anesthetics. (ii) In children without relevant preexisting illnesses (ie, ASA status I/II) who are scheduled for elective minor or medium-risk surgical procedures, no routine blood tests should be performed. (iii) Parental presence during the induction of anesthesia should be an option for children whenever possible. (iv) Perioperative fasting should be safe and child-friendly with shorter real fasting times and more liberal postoperative drinking and enteral feeding. (v) Perioperative fluid therapy should be safe and effective with physiologically composed balanced electrolyte solutions to maintain a normal extracellular fluid volume; addition of 1%-2.5% glucose to avoid lipolysis, hypoglycemia, and hyperglycemia, and colloids as needed to maintain a normal blood volume. (vi) To achieve safe and successful airway management, the locally accepted airway algorithm and continued teaching and training of basic and alternative techniques of ventilation and endotracheal intubation are required. (vii) Ultrasound and imaging systems (eg, transillumination) should be available for achieving central venous access and challenging peripheral venous and arterial access. (viii) Perioperative disturbances of the patient's homeostasis, such as hypotension, hypocapnia, hypothermia, hypoglycemia, hyponatremia, and severe anemia, should not be ignored and should be prevented or treated immediately. (ix) Pediatric patients with an elevated perioperative risk, eg, preterm and term neonates, infants, and critically ill children, should be treated at institutions where all caregivers have sufficient expertise and continuous clinical exposure to such patients. (x) A strategy for preventing postoperative vomiting, emergence delirium, and acute pain should be a part of every anesthetic procedure.

Fluid choice during perioperative care in children: A survey of present-day proposing practice by anesthesiologists in a tertiary care hospital

Background

Perioperative fluid therapy in pediatrics has always been a challenging avenue for anesthesiologists. Inappropriate choice of fluid leads to multiple side effects, for instance iatrogenic hyponatremia. Our aim was to observe the current practice of perioperative fluid therapy in pediatric population undergoing surgery in a tertiary care hospital.

Methods

After obtaining approval from the Departmental Research Review Committee, a survey form including questions was emailed to anesthesiologists from January 2015 to June 2015. Individual responses were recorded and analyzed.

Results

Overall response was 100% from consultant and resident, and total 55 anesthesiologists were participated in this survey. Majority of anesthesiologist have used, 1/2 dextrose saline (52.7%) as fluid of choice in routine intraoperative maintenance, while Hartmann's solution (41.8%) and normal saline 0.9% (5.5%) were used for rest of the them. The Holliday-Segar method for maintenance fluid was mentioned by 92.7% of anesthesiologists.

Conclusion

The use of hypotonic fluid in perioperative care in pediatric population is still being practiced despite the current guidelines. These results point to a considerable gap between the available evidence and practice.

Perioperative intravenous fluid therapy in children: guidelines from the Association of the Scientific Medical Societies in Germany

This consensus- based S1 Guideline for perioperative infusion therapy in children is focused on safety and efficacy. The objective is to maintain or re-establish the child's normal physiological state (normovolemia, normal tissue perfusion, normal metabolic function, normal acid- base- electrolyte status). Therefore, the perioperative fasting times should be as short as possible to prevent patient discomfort, dehydration, and ketoacidosis. A physiologically composed balanced isotonic electrolyte solution (BS) with 1-2.5% glucose is recommended for the intraoperative background infusion to maintain normal glucose concentrations and to avoid hyponatremia, hyperchloremia, and lipolysis. Additional BS without glucose can be used in patients with circulatory instability until the desired effect is achieved. The additional use of colloids (albumin, gelatin, hydroxyethyl starch) is recommended to recover normovolemia and to avoid fluid overload when crystalloids alone are not sufficient and blood products are not indicated. Monitoring should be extended in cases with major surgery, and autotransfusion maneuvers should be performed to assess fluid responsiveness.

Fluid homeostasis in the neonate

The physiology of the neonate is ideally suited to the transition to extrauterine life followed by a period of rapid growth and development. Intravenous fluids and electrolytes should be prescribed with care in the neonate. Sodium and water requirements in the first few days of life are low and should be increased after the postnatal diuresis. Expansion of the extracellular fluid volume prior to the postnatal diuresis is associated with poor outcomes, particularly in preterm infants. Newborn infants are prone to hypoglycemia and require a source of intravenous glucose if enteral feeds are withheld. Anemia is common, and untreated is associated with poor outcomes. Liberal versus restrictive transfusion practices are controversial, but liberal transfusion practices (accompanied by measures to minimize donor exposure) may be associated with improved long-term outcomes. Intravenous crystalloids are as effective as albumin to treat hypotension, and semi-synthetic colloids cannot be recommended at this time. Inotropes should be used to treat hypotension unresponsive to intravenous fluid, ideally guided by assessment of perfusion rather than blood pressure alone. Noninvasive methods of assessing cardiac output have been validated in neonates. More studies are required to guide fluid management in neonates, particularly in those with sepsis or undergoing surgery. A balanced salt solution such as Hartmann's or Plasmalyte should be used to replace losses during surgery (and blood or coagulation factors as indicated). Excessive fluid administration during surgery should be avoided.

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.

Neonatal fluid management

Perioperative fluid management in paediatrics has been the subject of many controversies in recent years, but fluid management in the neonatal period has not been considered in most reviews and guidelines. The literature regarding neonatal fluid management mainly appears in the paediatric textbooks and few recent data are available, except for resuscitation and fluid loading during shock and major surgery. In the context of anaesthesia, many neonates requiring surgery within the first month of life have organ malformation and/or dysfunction. This article aims at reviewing basic physiological considerations important for neonatal fluid management and mainly focusses on fluid maintenance and replacement during surgery.

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.

A novel isotonic-balanced electrolyte solution with 1% glucose for perioperative fluid management in children- an animal experimental preauthorization study

BACKGROUND

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

OBJECTIVE

The objective of this prospective animal study was to determine the margin of safety of a novel isotonic-balanced electrolyte solution with 1% glucose (BS-G1) in comparison with normal saline with 1% glucose (NS-G1) in the case of accidental hyperhydration with a focus on acid-base electrolyte balance, glucose concentration, osmolality and intracranial pressure in piglets.

METHODS

Ten piglets (bodyweight 11.8 +/- 1.8 kg) were randomly assigned to receive either 100 ml.kg(-1) of BS-G1 or NS-G1 within one hour. Before, during and after fluid administration, electrolytes, lactate, hemoglobin, hematocrit, glucose, osmolality and acid-base parameters were measured.

RESULTS

Unlike BS-G1, administration of NS-G1 produced mild hyperchloremic acidosis (base excess BS-G1 vs NS-G1, baseline 1.9 +/- 1.7 vs 2.9 +/- 0.9 mmol.l(-1), study end 0.2 +/- 1.7 vs -2.7 +/- 0.5 mmol.l(-1), P < 0.05, chloride BS-G1 vs NS-G1 baseline 102.4 +/- 3.4 vs 102.0 +/- 0.7 mmol.l(-1), study end 103.4 +/- 1.8 vs 109.0 +/- 1.4 mmol.l(-1)P < 0.05). The addition of 1% glucose led to moderate hyperglycemia (P < 0.05) with a concomitant increase in serum osmolality in both groups (P < 0.05).

CONCLUSION

Both solutions showed a wide margin of safety in the case of accidental hyperhydration with less acid-base electrolyte changes when using BS-G1. This novel solution could therefore enhance patient's safety within the scope of perioperative volume management.

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.

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.

Optimizing intraoperative fluid therapy

PURPOSE OF REVIEW

Correcting the fluid status of the surgical patient is an integral part of good anaesthetic practice. There have been few areas in anaesthesia and perioperative medicine as controversial as fluid resuscitation. Uncertainties still exist as to what the best solution to give is, whether it be a colloid or a crystalloid, and how and when to give it. As well as increasing awareness of the different properties of various colloids, there has been interest in the nature of the carrier solutions, essentially a choice between saline or Ringer's lactate (compound sodium lactate or Hartmann's solution). In this article we review recent studies involving crystalloids, the 'new colloids', and on the amount and timing of fluid therapy.

RECENT FINDINGS

Saline based fluids (including most colloids) are associated with a hyperchloremic metabolic acidosis, and a hypocoagulable state, although these may not necessarily harm the patient. Saline may have deleterious effects on renal function. Colloids in solutions similar to Ringer's lactate ('balanced solutions') may avoid these effects although few are currently available. Several studies that have used fluids (along with other therapies) to improve organ perfusion around the time of surgery have been associated with a better outcome.

SUMMARY

Compared with Ringer's lactate, saline, and saline-based colloids are associated with a hyperchloremic metabolic acidosis, and a hypocoagulable state although they may not be associated with adverse patient outcomes. Increasing awareness of the 'Stewart hypothesis' has led to new ways of managing hyperchloremic metabolic acidosis. The 'crystalloid-colloid debate' continues, and has led to an awareness that these different fluids, along with their carrier solutions are drugs with different effects. Several studies, in which patients have received more fluid in the protocol group, have found better clinical outcomes in the 'optimized' patients.

Perioperative fluid therapy in children: a survey of current prescribing practice †

BACKGROUND

Fluid therapy in children may be associated with iatrogenic hyponatraemia. We surveyed anaesthetists' current fluid prescribing practice during the perioperative period, departmental fluid protocols and awareness of the concerns of the Royal College of Paediatrics and Child Health (RCPCH) about the use of dextrose 4%/saline 0.18% in children.

METHODS

Questionnaire survey of 477 consultant anaesthetists in two training areas in the UK.

RESULTS

Responses were received from 289 anaesthetists (60.6%)--responses from the 203 consultants that anaesthetized children were analysed. A total of 67.7% did not have a local departmental policy for fluid prescription, and 58.1% were unaware of the concerns of RCPCH. A total of 60.1% of anaesthetists said that they prescribed hypotonic dextrose saline solutions in the intraoperative period and 75.2% did so in the postoperative period. Anaesthetists working in specialist paediatric hospitals were 5.1 times more likely to prescribe isotonic fluids intraoperatively than those working in district hospitals (95% CI 1.48-17.65, P=0.01), but they all prescribed hypotonic dextrose saline solutions postoperatively. The Holliday and Segar formula for maintenance fluid was quoted by 81.8% of anaesthetists; only 5.9% of anaesthetists would restrict fluids in the immediate postoperative period. Anaesthetists working in specialist paediatric hospitals were 13.2 times more likely to restrict fluids postoperatively than those working in district hospitals (95% CI 2.8-61.8, P=0.001).

CONCLUSIONS

The prescription of hypotonic dextrose saline solutions by anaesthetists may be putting children at risk from iatrogenic hyponatraemia. Departmental protocols for perioperative fluid prescription in children are uncommon. We suggest that national guidance is required.

[Postoperative hyponatremia in children: pathophysiology, diagnosis and treatment]

OBJECTIVES

To review the current data on pathophysiology, causes and management of postoperative hyponatremia in children.

DATA SOURCES AND EXTRACTION

The Pubmed database was searched for articles, combined with references analysis of major articles on the field.

DATA SYNTHESIS

The incidence of postoperative hyponatremia has been evaluated at 0.34% and its mortality significant. Postoperative hyponatremia is triggered by the diminished renal ability to excrete free water, due to antidiuretic hormone release. Inappropriate secretion of antidiuretic hormone is frequently seen after spine, cardiac and neurosurgery but can occur even after minor surgery. In this context, the infusion of hypotonic fluids represents a strong risk factor for developing hyponatremia. Other causes of hyponatremia are represented by extrarenal fluid losses, cerebral salt wasting syndrome, desalination phenomenon, adrenal insufficiency or some medications. Preventive treatment is essential and based on prohibition of hypotonic fluids infusion and the use of isotonic fluids infusions, maintenance of a normal total blood volume, the observance of the good practice recommendations for fluid infusion in children, and frequent blood and urine sodium concentration determinations in patients at risk for developing hyponatremia. Hyponatremic encephalopathy requires an emergent management, consisting in respiratory care and hypertonic sodium chloride infusion. Chronic hyponatremia is most often asymptomatic and the main neurological risk factor is represented by a too rapid correction of plasma sodium, which may lead to centropontine myelinolysis.

The maintenance need for water in parenteral fluid therapy

PURPOSE OF REVIEW

Maintenance fluid therapy represents the volume of fluids and amount of electrolytes and glucose needed to replace anticipated physiological losses from breath, sweat and urine and to prevent hypoglycaemia. For 50 years, this therapy was based on Holliday and Segar's formula, which proposed to match children's water and electrolyte requirements on a weight-based calculation using hypotonic solutions. Recent publications highlight the risk of hyponatraemia in the postoperative period and the facilitating role of a hypotonic infusion, leading some people to recommend replacing hypotonic with isotonic solutions.

RECENT FINDINGS

The postoperative period is at risk for nonosmotic secretion of antidiuretic hormone, which reduces the ability of the kidneys to excrete free water. In the context of antidiuretic hormone release, the associated low urine output makes maintenance volume requirement decrease to 50% of the calculated hourly rate. While isotonic fluids are recommended during anaesthesia, controversies still exist on the nature of fluid for maintenance therapy in the postoperative period. The proof for a benefit of isotonic fluids in this context is weak; further investigations are needed to make a decision. Whatever the choice, an individualized maintenance infusion protocol for each patient is necessary.

SUMMARY

As free water excretion is altered for all children in the postoperative period, it is necessary to reduce the volume of maintenance fluid therapy to half the previously recommended volume. The choice of an isotonic solution should be more pertinent to that of a hypotonic solution, but evidence is lacking for a definitive answer.