How to select optimal maintenance intravenous fluid therapy

Evaluation and management of hypernatremia in adults: clinical perspectives

Hypernatremia is an occasionally encountered electrolyte disorder, which may lead to fatal consequences under improper management. Hypernatremia is a disorder of the homeostatic status regarding body water and sodium contents. This imbalance is the basis for the diagnostic approach to hypernatremia. We summarize the eight diagnostic steps of the traditional approach and introduce new biomarkers: exclude pseudohypernatremia, confirm glucose-corrected sodium concentrations, determine the extracellular volume status, measure urine sodium levels, measure urine volume and osmolality, check ongoing urinary electrolyte free water clearance, determine arginine vasopressin/copeptin levels, and assess other electrolyte disorders. Moreover, we suggest six steps to manage hypernatremia by replacing water deficits, ongoing water losses, and insensible water losses: identify underlying causes, distinguish between acute and chronic hypernatremia, determine the amount and rate of water administration, select the type of replacement solution, adjust the treatment schedule, and consider additional therapy for diabetes insipidus. Physicians may apply some of these steps to all patients with hypernatremia, and can also adapt the regimens for specific causes or situations.

Intravenous Infusion of Sterile Water for the Treatment of Hypernatraemia

Little research has been carried out into the infusion of intravenous sterile water for the treatment of hypernatraemia, and it remains a contentious issue. We conducted a review of the literature and extract results following an extensive search of Medline 1946, Embase 1974, ProQuest, evidence-based practice resources, national and international guideline sites and the publications of various professional bodies. The review is presented on the infusion of sterile water (hypotonic fluid) to lower serum sodium level in those circumstances when enteral supplementation of water is not possible, such as in postoperative patients or when other isotonic fluids (such as 5% dextrose in water infusion) are less than ideal—for example, hyperglycaemic patients on an insulin infusion. Absence of guidelines has limited the use of sterile water, even as an off-label drug when it can be administered relatively safely via a central line.

Acute Hyponatremia After a Religious Fast

Objective

Our objective is to describe how polydipsia and intake of nonsteroidal anti-inflammatory drugs (NSAIDs) after fasting while breastfeeding may result in acute symptomatic hyponatremia.

Case Report

We present the case of a 24-year-old woman at 4 weeks postpartum who engaged in a 20-hour fast from both eating and drinking, during which she continued to breastfeed her newborn child. After ending her fast, she noted decreased milk supply. Attributing her decreased milk supply to dehydration, she then consumed 4 L of water with little salt and also took NSAIDs for a headache, which continued to worsen. Upon presentation to the emergency department, she was found to have a sodium level of 124 mEq/L (normal, 135-145 mEq/L) and a urine specific gravity of 1.015 (normal, 1.005 – 1.030). Thyroid function and cortisol level test results were normal. She was diagnosed with acute symptomatic hypovolemic hyponatremia. After 1 L of normal saline her sodium rapidly corrected to normal and her symptoms resolved. At 2 months of follow-up she was asymptomatic and had no further episodes of hyponatremia.

Discussion

Due to the patient’s gender and small body size, 4 L of water was sufficient to lower her serum sodium rapidly from normal to 124 mEq/L. She was unable to excrete this water due to a combination of hypovolemia-mediated arginine vasopressin and NSAID use.

Conclusion

Clinicians should be cognizant that reproductive-age women are uniquely susceptible to hyponatremia and dangerous sequelae therein. They should counsel fasting individuals, particularly lactating women, to consume solute as well as fluid after fasting.

Comparison of isotonic versus hypotonic intravenous fluid for maintenance fluid therapy in neonates more than or equal to 34 weeks of gestational age - a randomized clinical trial

BACKGROUND AND OBJECTIVES

The use of hypotonic fluids as maintenance therapy in the neonatal population has been in practice for a long time, but there is a lack of evidence for the choice of this fluid in neonates. This study compared isotonic (sodium chloride, 0.9%, and dextrose, 5%) versus hypotonic (sodium chloride, 0.15%, and dextrose, 5%) intravenous fluid for maintenance fluid therapy in neonates more than or equal to 34 weeks of gestational age.

METHODS

In this triple-blind randomized clinical trial, we recruited 60 neonates admitted to a neonatal intensive care unit of a tertiary care children's hospital from June 2017 through May 2018 with normal baseline serum sodium levels, anticipated to require intravenous maintenance fluids for 24 hours or longer (intention-to-treat analyses). Patients were randomized to receive isotonic or hypotonic intravenous fluid at maintenance rates for 72 hours. The primary outcome was the incidence of hyponatremia (defined as serum sodium <135mEq/L) at 24 hours in both groups. The secondary outcomes were incidence of hypernatremia at 24 hours (defined as serum sodium >145 mEq/L), the incidence of hypo and hypernatremia at 48 and 72 hours, mean serum sodium at 24, 48, and 72 hours, rate of change of serum sodium during the study period, mean serum osmolality at the end of the study period, the absolute difference in osmolality during the study period, the absolute difference in weight during the study period and edema during the study period.

RESULTS

Of 60 enrolled neonates, 31 received isotonic fluids and 29 received hypotonic fluids. Three patients in the hypotonic group developed hyponatremia and none in isotonic group at 24 h (RR = 0.13; 95% CI = 0.007 - 2.485; p = .106). Fourteen neonates developed hypernatremia in the isotonic group and one in hypotonic group at 24 h (RR = 13.09; 95% CI = 1.83 - 93.4; p = .0001).

CONCLUSIONS

Our study results do not support the hypothesis that isotonic fluid is superior to hypotonic fluid in reducing the proportion of neonates developing hyponatremia after 24 hours of intravenous fluid therapy. The proportion of neonates developing hypernatremia is significantly higher after using isotonic fluid for maintenance therapy. TRIAL REGISTRATION CTRI/2017/05/008585.

Hypotonic and isotonic intravenous maintenance fluids in hospitalised paediatric patients: a randomised controlled trial

OBJECTIVE

To compare the changes in serum sodium and acid/base status in patients receiving hypotonic and isotonic solutions.

DESIGN

A randomised, controlled and double-blind clinical trial.

SETTING

Department of Paediatrics in a tertiary general hospital (Hospital Universitario Austral) in Buenos Aires, Argentina.

PATIENTS

Children between 29 days and 15 years of age who were hospitalised in the paediatric intensive care unit and general hospital between 12 January 2010 and 30 November 2016, and who required exclusively parenteral maintenance solutions for at least 24 hours.

INTERVENTIONS

A hypotonic solution with 77 mEq/L sodium chloride (0.45% in 5% dextrose) and isotonic solution with 150 mEq/L (0.9% in 5% dextrose) were infused for 48 hours and were labelled.

MAIN OUTCOME MEASURE

The main outcome was to evaluate the incidence of hyponatraemia between patients treated with parenteral hydration with hypotonic or isotonic fluids. The secondary outcome was to estimate the incidence of metabolic acidosis induced by each of the solutions.

RESULTS

The 299 patients in the present study were randomised to groups that received the hypotonic solution (n=154) or isotonic solution (n=145). The mean serum sodium concentration measurements at 12 hours were 136.3±3.9 mEq/L and 140.1±2.3 mEq/L in the hypotonic and isotonic groups, respectively, with a hyponatraemia incidence of 8.27% (n=12) and 18.8% (n=29) (p<0.001). At 24 hours, 12.4% (n=18) of the isotonic group had developed hyponatraemia compared with 46.1% (n=71) of the hypotonic group (p<0.001). The mean serum sodium concentration measurements were 134.4±5.6 and 139.3±3.1, respectively. No patient developed hypernatraemia (serum sodium concentrations >150 mEq/L) or other adverse outcomes. The relative risk in the hypotonic group was 3.7 (95% CI 2.3 to 5.9), almost four times the risk of developing hyponatraemia than those who received isotonic fluids. There were also no significant differences between the groups with regard to the development of metabolic acidosis. Hypotonic solution, age <12 months and postoperative abdominal surgery were risk factors associated with hyponatraemia.

CONCLUSIONS

The incidence of iatrogenic hyponatraemia was greater with the administration of hypotonic fluids compared with that of isotonic fluids. There were no significant differences in the incidence of metabolic acidosis between the groups.

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.

A randomized, double-blinded, controlled trial of the effects of fluid rate and/or presence of dextrose in intravenous fluids on the labor course of nulliparas

BACKGROUND

Prolonged labor has been demonstrated to increase adverse maternal and neonatal outcome. A practice that may decrease the risk of prolonged labor is the modification of fluid intake during labor.

OBJECTIVE

Several studies demonstrated that increased hydration in labor as well as addition of dextrose-containing fluids may be associated with a decrease in length of labor. The purpose of our study was to characterize whether high-dose intravenous fluids, standard-dose fluids with dextrose, or high-dose fluids with dextrose show a difference in the duration of labor in nulliparas.

STUDY DESIGN

Nulliparous subjects with singletons who presented in active labor were randomized to 1 of 3 groups of intravenous fluids: 250 mL/h of normal saline, 125 mL/h of 5% dextrose in normal saline, or 250 mL/h of 2.5% dextrose in normal saline. The primary outcome was total length of labor from initiation of intravenous fluid in vaginally delivered subjects. Secondary outcomes included cesarean delivery rate and length of second stage of labor, among other maternal and neonatal outcomes.

RESULTS

In all, 274 subjects who met inclusion criteria were enrolled. There were no differences in baseline characteristics among the 3 groups. There was no difference in the primary outcome of total length of labor in vaginally delivered subjects among the 3 groups. First stage of labor duration, second stage of labor duration, and cesarean delivery rates were also equivalent. There were no differences identified in other secondary outcomes including clinical chorioamnionitis, postpartum hemorrhage, blood loss, Apgar scores, or neonatal intensive care admission.

CONCLUSION

There is no difference in length of labor or delivery outcomes when comparing high-dose intravenous fluids, addition of dextrose, or use of high-dose intravenous fluids with dextrose in nulliparous women who present in active labor.

Comparison of the incidences of hyponatremia in adult postoperative critically ill patients receiving intravenous maintenance fluids with 140 mmol/L or 35 mmol/L of sodium: retrospective before/after observational study

PURPOSE

The purpose of this study was to compare the incidences of hyponatremia in adult postoperative critically ill patients receiving isotonic and hypotonic maintenance fluids.

METHODS

In this single-center retrospective before/after observational study, we included patients who had undergone an elective operation for esophageal cancer or for head and neck cancer and who received postoperative intensive care for >48 h from August 2014 to July 2016. In those patients, sodium-poor solution (35 mmol/L of sodium; Na₃₅) had been administered as maintenance fluid until July 2015. From August 2015, the protocol for postoperative maintenance fluid was revised to the use of isotonic fluid (140 mmol/L of sodium; Na₁₄₀). The primary outcome was the incidence of hyponatremia (<135 mmol/L) until the morning of postoperative day (POD) 2.

RESULTS

We included 179 patients (Na₃₅: 87 patients, Na₁₄₀: 92 patients) in the current study. The mean volume of fluid received from ICU admission to POD 2 was not significantly different between the two groups (3291 vs 3337 mL, p = 0.84). The incidence of postoperative hyponatremia was 16.3% (15/92) in the Na₁₄₀ cohort, which was significantly lower than that of 52.9% (46/87) in the Na₃₅ group (odds ratio = 0.17, 95% confidence interval 0.09-0.35, p < 0.001]. The incidences of hypernatremia, defined as serum sodium concentration >145 mmol/L, were not significantly different between the two groups.

CONCLUSION

In this study, the use of intravenous maintenance fluid with 35 mmol/L of sodium was significantly associated with an increased risk of hyponatremia compared to that with 140 mmol/L of sodium in adult postoperative critically ill patients.

Intravenous isotonic fluids induced a positive trend in natraemia in children admitted to a general paediatric ward

AIM

Using hypotonic intravenous solutions for baseline fluid needs in paediatric patients on a nil by mouth diet may cause serious complications, including hyponatraemia, cerebral oedema and even death. We analysed the evolution of natraemia and explored any adverse effects on children treated with intravenous isotonic fluids.

METHODS

This was a prospective study of 50 patients consecutively admitted to a general paediatric ward who were treated with isotonic intravenous fluids and on a nil by mouth diet.

RESULTS

The most prevalent diagnosis was acute gastroenteritis (64%). Hyponatraemia, defined as sodium in plasma of <135 mEq/L, affected 22% of the subjects, but none displayed this during the first postadmission analysis at a median of eight hours. Sodium levels changed by an average of +0.64 mEq/L/hour. The subgroup analysis (0.91 versus 0.56 mEq/L/hour, p = 0.02) and multiple linear regression (R(2) = 0.756) showed a greater increase in sodium when patients had hyponatraemia on admission. Iatrogenic hyponatraemia was not detected, but two patients showed mild hypernatraemia and 35% developed clinically insignificant hyperchloraemia.

CONCLUSION

Using intravenous isotonic fluids induced a positive trend in natraemia on a general paediatric ward, particularly if patients were hyponatraemic when admitted, and did not induce clinically relevant adverse effects.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

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

METHODS

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

MAIN OUTCOME MEASURED

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

RESULTS

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

CONCLUSIONS

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

Intravenous solutions in the care of patients with volume depletion and electrolyte abnormalities

Infusion fluids are often given to restore blood pressure (volume resuscitation), but may also be administered to replace ongoing losses, match insensible losses, correct electrolyte or acid-base disorders, or provide glucose. The development of new infusion fluids has provided clinicians with a wide range of products. Although the choice for a certain infusion fluid is often driven more by habit than by careful consideration, we believe it is useful to approach infusion fluids as drugs and consider their pharmacokinetic and pharmacodynamic characteristics. This approach not only explains why infusion fluids may cause electrolyte and acid-base disturbances, but also why they may compromise kidney function or coagulation. In this teaching case, we present a 19-year-old patient in whom severe hypernatremia developed as a result of normal saline solution infusion and explore the pharmacokinetic and pharmacodynamic effects of frequently used infusion fluids. We review clinical evidence to guide the selection of the optimal infusion fluid.

Doppler ultrasonographic evaluation of renal arterial resistive and pulsatility indices in overhydrated Beagles

OBJECTIVE

To determine renal arterial resistive index (RI) and pulsatility index (PI) and clinical signs of overhydration induced by IV administration of saline (0.9% NaCl) solution and to assess RI and PI as variables for monitoring of dogs to detect overhydration.

ANIMALS

10 clinically normal Beagles.

PROCEDURES

Each dog received saline solution at a maintenance rate (2.5 mL/kg/h) and a rate 3 times that of the maintenance rate (overhydration rate; 7. 5 mL/kg/h). Values of RI and PI were determined with pulsed-wave Doppler ultrasonographic examination of renal interlobar or arcuate arteries before saline solution administration, every hour during 5 hours of administration, and 1 hour after administration was stopped.

RESULTS

No significant changes in RI or PI were detected during administration of saline solution at the maintenance rate. However, RI (starting 1 hour after the beginning of fluid administration [mean ± SD value, 0.589 ± 0.012]) and PI (starting 2 hours after the beginning of fluid administration [value, 0.867 ± 0.052]) were significantly lower during administration at the overhydration rate than they were during administration at the maintenance rate. Clinical signs of overhydration were observed in all dogs starting 4 hours after the beginning of fluid administration at the overhydration rate.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated overhydration of dogs caused significant decreases in RI and PI prior to detection of clinical signs of overhydration. Ultrasonographic determination of renal arterial RI and PI seemed to be a noninvasive and sensitive method for evaluation of overhydration in dogs.

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.

A clinical approach to the treatment of chronic hypernatremia

Hypernatremia is a commonly encountered electrolyte disorder occurring in both the inpatient and outpatient settings. Community-acquired hypernatremia typically occurs at the extremes of age, whereas hospital-acquired hypernatremia affects patients of all age groups. Serum sodium concentration is linked to water homeostasis, which is dependent on the thirst mechanism, arginine vasopressin, and kidney function. Because both hypernatremia and the rate of correction of hypernatremia are associated with significant morbidity and mortality, prompt effective treatment is crucial. Chronic hypernatremia can be classified into 3 broad categories, hypovolemic, euvolemic, and hypervolemic forms, with each form having unique treatment considerations. In this teaching case, we provide a clinically based quantitative approach to the treatment of both hypervolemic and hypovolemic hypernatremia, which occurred in the same patient during the course of a prolonged illness.

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.

Iatrogenic hyponatremia in hospitalized children: Can it be avoided?

Iatrogenic hyponatremia in hospitalized children is a common problem. It is usually caused by the administration of free water, either orally or through the prescription of hypotonic intravenous fluids. It can result in cerebral edema and death, and is most commonly reported in healthy children undergoing minor surgery. The current teachings and practical guidelines for maintenance fluid infusions are based on caloric expenditure data in healthy children that were derived and published more than 50 years ago. A re-evaluation of these data and more recent recognition that hospitalized children are vulnerable to hyponatremia, with its resulting morbidity and mortality rates, suggest that changes in paediatricians' approach to fluid administration are necessary. There is no single fluid therapy that is optimal for all hospitalized children. A thorough assessment of the type of fluid, volume of fluid and electrolyte requirements based on individual patient requirements, plus rigorous monitoring, is required in any child receiving intravenous fluids. The present article reviews how hyponatremia occurs and makes recommendations for minimizing the risk of iatrogenic hyponatremia.

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.

A meta-analysis of randomised controlled trials of intravenous fluid therapy in major elective open abdominal surgery: getting the balance right

The terminology used for describing intervention groups in randomised controlled trials (RCT) on the effect of intravenous fluid on outcome in abdominal surgery has been imprecise, and the lack of standardised definitions of the terms 'standard', 'restricted' and 'liberal' has led to some confusion and difficulty in interpreting the literature. The aims of this paper were to clarify these definitions and to use them to perform a meta-analysis of nine RCT on primarily crystalloid-based peri-operative intravenous fluid therapy in 801 patients undergoing elective open abdominal surgery. Patients who received more or less fluids than those who received a 'balanced' amount were considered to be in a state of 'fluid imbalance'. When 'restricted' fluid regimens were compared with 'standard or liberal' fluid regimens, there was no difference in post-operative complication rates (risk ratio 0.83 (95% CI 0.49, 1.39, P = 0.47) [corrected] or length of hospital stay (weighted mean difference (WMD) - 1.77 (95% CI - 4.36, 0.81) d, P = 0.18). However, when the fluid regimens were reclassified and patients were grouped into those who were managed in a state of fluid 'balance' or 'imbalance', the former group had significantly fewer complications (risk ratio 0·59 (95% CI 0·44, 0·81), P=0·0008) and a shorter length of stay (WMD -3·44 (95% CI -6·33, -0·54) d, P=0·02) than the latter. Using imprecise terminology, there was no apparent difference between the effects of fluid-restricted and standard or liberal fluid regimens on outcome in patients undergoing elective open abdominal surgery. However, patients managed in a state of fluid balance fared better than those managed in a state of fluid imbalance.

HES 130/0.4 (Voluven) or human albumin in children younger than 2 yr undergoing non-cardiac surgery. A prospective, randomized, open label, multicentre trial

BACKGROUND AND OBJECTIVE

For perioperative volume therapy in infants and young children, human albumin has frequently been the colloid of choice. Recently, HES 130/0.4 (6% hydroxyethyl starch, Voluven; Fresenius Kabi, Bad Homburg, Germany) was developed, which demonstrated improved pharmacokinetics and a favourable safety profile in adults compared with hydroxyethyl starch products with a less rapid metabolization.

METHODS

Our prospective, controlled, randomized, open, multicentre pilot study was designed to obtain data on the effects of HES 130/0.4 compared with human albumin 5% with regard to haemodynamics in children <2 yr scheduled for elective non-cardiac surgery.

RESULTS

A total of 81 patients were treated. Comparable amounts of both study solutions (16.0 mL kg(-1) hydroxyethyl starch 130/0.4 vs. 16.9 mL kg(-1) human albumin 5%) as well as add-on crystalloids were used until 4-6 h postoperatively. No differences were detected between the two treatment groups regarding perioperative stabilization of haemodynamics, coagulation parameters, blood gas analyses or other laboratory values. Blood loss was 96 +/-143 mL for hydroxyethyl starch and 145+/- 290 mL for human albumin (P > 0.05). There were no relevant differences in the amount of red blood cells, fresh frozen plasma or platelet concentrates in both treatment groups. Median length of ICU stay was 3.5 days (range 1-57 days, mean +/- SD 7.6 +/- 11.5 days) in the hydroxyethyl starch group and 6.0 days (range 1-71 days; mean +/- SD 9.1 +/- 14.2 days) in the human albumin group. There was no difference for hospital stay (median: 12 days for both groups).

CONCLUSIONS

Both HES 130/0.4 and human albumin 5% were effective for haemodynamic stabilization in non-cardiac surgery of young infants with no adverse impact on coagulation or other safety parameters in our study population.

Intravenous fluid administration in elderly patients at a London hospital: A two-part audit encompassing ward-based fluid monitoring and prescribing practice by doctors

BACKGROUND AND AIM

Elderly patients are vulnerable to complications of intravenous fluid overload, however daily monitoring of fluid balance in this population has been highlighted as sub optimal by the NCEPOD. We compare current practice in fluid balance monitoring and intravenous fluid prescribing for elderly patients in a London District General Hospital to guidelines for fluid management in children issued by the National Patient Safety Agency.

METHODS

This study consists of two parts: (1) a ward-based survey of fluid balance monitoring in all patients above the age of 65 receiving intravenous fluids; (2) an anonymous questionnaire completed by 20 doctors of a variety of grades and specialities on the parameters of fluid balance routinely checked by doctors prior to prescribing intravenous fluids.

RESULTS

The results highlight that the most frequently monitored parameters of fluid balance are daily serum urea, creatinine and sodium levels (65.1% of patients receiving intravenous fluids on the wards, 85% of doctors check these levels before prescribing fluids). Initial weight is measured in one quarter of patients; daily weight is monitored in 9.4% of patients and 25% of doctors check daily weight before prescribing intravenous fluids.

CONCLUSION

Initial and daily weights are non-invasive parameters of fluid balance that are infrequently monitored in elderly patients receiving intravenous fluids. We propose that all elderly patients should be weighed (1) on admission to the Emergency Department, (2) prior to commencement of intravenous fluids and (3) on a regular basis, preferably daily, for the duration of intravenous fluid administration. For immobile patients, strict fluid input-output charts should be maintained as a surrogate index of changes in daily weight. We encourage consistent and accurate documentation of these non-invasive parameters on the fluid prescription charts.

Intravenous fluid therapy: a randomized controlled trial to investigate the effectiveness of the IV(2) flow medical device

OBJECTIVES

To investigate the hypothetical benefits of the IV(2) flow medical device.

BACKGROUND

Intravenous fluid administration is a standard hospital procedure with assumed inadequacies. The IV-Event Study [Fraser N, Nel G, Snyman J & Wessels F (2004) IV-EVENT Study: Intravenous Infusion Therapy--Management and Adverse Events. Data on File: Varori International (Pty) Ltd., Centurion, South Africa] quantified these inadequacies; The 'Stargait' intervention trial investigated the effectiveness and possible cost-benefit of the IV(2) flow. The IV(2) flow is intended for routine use with gravitational intravenous infusion sets. The IV(2) flow should reduce the incidence rate of adverse events and maintain a set flow rate.

METHOD

Nursing staff assisted by study assessors captured relevant data. Consented patients were enrolled for the period of their prescribed infusions. Intervention. The Stargait Trial compared the treatment group (standard gravitational sets with the IV(2) flow) with the control group (standard gravitational infusion sets without IV(2) flow). The difference in observed events and the cost benefit derived from this were measured.

RESULTS

A total of 2387 drip hours were observed in 52 patients. The adverse event rates were: Control group (without IV(2) flow) 33.8%. The treatment group (IV(2) flow) 15.4%. This 55% reduction is statistically significant (p = 0.0069). Adverse event related monetary wastage (labour and consumables) is reduced by 76% for infusion bags in the intervention group (with IV(2) flow). There was a significant difference between the treatment group and control group as far as deviation in flow rate was concerned (p = 0.00818). The mean deviation of the IV(2) flow group was just more than 5 ml per hour. The standard line group had a mean deviation of more than 30 ml per hour.

CONCLUSION

Gravitational intravenous therapy compromises quality of patient care. The Stargait Trial has proven the care-effectiveness and cost-effectiveness of the IV(2) flow.

RELEVANCE TO CLINICAL PRACTICE

The IV(2) flow improves quality of patient care and reduces associated wastage.

Preventing a drop in effective plasma osmolality to minimize the likelihood of cerebral edema during treatment of children with diabetic ketoacidosis

OBJECTIVES

To test whether a drop in effective plasma osmolality (P(Eff osm); 2 x plasma sodium [P(Na)] + plasma glucose concentrations) during therapy for diabetic ketoacidosis (DKA) is associated with an increased risk of cerebral edema (CE), and whether the development of hypernatremia to prevent a drop in the P(Eff osm) is dangerous.

STUDY DESIGN

This study is a retrospective comparison of a CE group (n = 12) and non-CE groups with hypernatremia (n = 44) and without hypernatremia (n = 13).

RESULTS

The development of CE (at 6.8 +/- 1.5 hours) was associated with a drop in P(Eff osm) from 304 +/- 5 to 290 +/- 5 mOsm/kg (P < .001). Control patients did not show this drop in P(Eff osm) at 4 hours (1 +/- 2 and 2 +/- 2 vs -9 +/- 2 mOsm/kg; P < .01), because of a larger rise in P(Na) and/or a smaller drop in plasma glucose. During this period, the CE group received more near-isotonic fluids (69 +/- 9 vs 35 +/- 2 and 27 +/- 3 mL/kg; P < .001). The CE group had a higher mortality (3/12 vs 0/57; P = .003), and more neurologic sequelae (5/12 vs 1/57; P < .001).

CONCLUSIONS

CE during therapy for DKA was associated with a drop in P(Eff osm). An adequate rise in P(Na) may be needed to prevent this drop in P(Eff osm).

Fluid, electrolytes and nutrition: physiological and clinical aspects

Fluid and electrolyte balance is often poorly understood and inappropriate prescribing can cause increased post-operative morbidity and mortality. The efficiency of the physiological response to a salt or water deficit, developed through evolution, contrasts with the relatively inefficient mechanism for dealing with salt excess. Saline has a Na+:Cl-of 1:1 and can produce hyperchloraemic acidosis, renal vasoconstriction and reduced glomerular filtration rate. In contrast, the more physiological Hartmann's solution with a Na+:Cl-of 1·18:1 does not cause hyperchloraemia and Na excretion following infusion is more rapid. Salt and water overload causes not only peripheral and pulmonary oedema, but may also produce splanchnic oedema, resulting in ileus or acute intestinal failure. This overload may sometimes be an inevitable consequence of resuscitation, yet it may take 3 weeks to excrete this excess. It is important to avoid unnecessary additional overload by not prescribing excessive maintenance fluids after the need for resuscitation has passed. Most patients require 2–2·5 litres water and 60–100?mmol?Na\d for maintenance in order to prevent a positive fluid balance. This requirement must not be confused with those for resuscitation of the hypovolaemic patient in whom the main aim of fluid therapy is repletion of the intravascular volume. Fluid and electrolyte balance is a vital component of the metabolic care of surgical and critically-ill patients, with important consequences for gastrointestinal function and hence nutrition. It is also of importance when prescribing artificial nutrition and should be given the same careful consideration as other nutritional and pharmacological needs.

How perioperative fluid balance influences postoperative outcomes

Fasting, anaesthesia and surgery affect the body's physiological capacity not only to control its external fluid and electrolyte balance but also the internal balance between the various body fluid compartments. Conversely, abnormalities of fluid and electrolyte balance may adversely affect organ function and surgical outcome. Perioperative fluid therapy has a direct bearing on outcome, and prescriptions should be tailored to the needs of the patient. The goal of fluid therapy in the elective setting is to maintain the effective circulatory volume while avoiding interstitial fluid overload whenever possible. Weight gain in elective surgical patients should be minimized in an attempt to achieve a 'zero fluid balance status'. On the other hand, these patients should arrive in the anaesthetic room in a state of normal fluid and electrolyte balance so as to avoid the need to resuscitate fluid-depleted patients in the anaesthetic room or after the induction of anaesthesia. Optimal fluid delivery should be part of an overall care package that involves minimization of the period of preoperative fasting, preoperative carbohydrate loading, thoracic epidural analgesia, avoidance of nasogastric tubes, early mobilization, and early return to oral feeding, as exemplified by the enhanced recovery after surgery programme.

Hypotonic versus isotonic saline in hospitalised children: a systematic review

BACKGROUND

The traditional recommendations which suggest that hypotonic intravenous (i.v.) maintenance fluids are the solutions of choice in paediatric patients have not been rigorously tested in clinical trials, and may not be appropriate for all children.

AIMS

To systematically review the evidence from studies evaluating the safety of administering hypotonic versus isotonic i.v. maintenance fluids in hospitalised children.

DATA SOURCES

Medline (1966-2006), Embase (1980-2006), the Cochrane Library, abstract proceedings, personal files, and reference lists. Studies that compared hypotonic to isotonic maintenance solutions in children were selected. Case reports and studies in neonates or patients with a pre-existing history of hyponatraemia were excluded.

RESULTS

Six studies met the selection criteria. A meta-analysis combining these studies showed that hypotonic solutions significantly increased the risk of developing acute hyponatraemia (OR 17.22; 95% CI 8.67 to 34.2), and resulted in greater patient morbidity.

CONCLUSIONS

The current practice of prescribing i.v. maintenance fluids in children is based on limited clinical experimental evidence from poorly and differently designed studies, where bias could possibly raise doubt about the results. They do not provide evidence for optimal fluid and electrolyte homoeostasis in hospitalised children. This systematic review indicates potential harm with hypotonic solutions in children, which can be anticipated and avoided with isotonic solutions. No single fluid rate or composition is ideal for all children. However, isotonic or near-isotonic solutions may be more physiological, and therefore a safer choice in the acute phase of illness and perioperative period.

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.

Acute and fatal hyponatraemia after resection of a craniopharyngioma: a preventable tragedy

Central diabetes insipidus developed for the first time in a 14-year-old female during the resection of a craniopharyngioma. The water diuresis persisted until a vasopressin analogue (dDAVP) was given. Professor McCance was asked to explain why hypernatraemia developed, to anticipate dangers that might develop in the salt and water area with therapy, and to provide insights into why this patient died, due to the subsequent development of hyponatraemia that caused a lethal rise in intracranial pressure. The team specifically wanted Professor McCance's opinions as to why a PNa of 124 mmol/l was uniquely dangerous for this patient, and this was a particularly challenging conundrum. Nevertheless, with the aid of a mini-experiment, a careful chart review, and creative thinking, he was able to offer a novel solution, and to suggest ways to prevent its occurrence in other patients.

Some interactions between gastrointestinal function and fluid and electrolyte homeostasis

PURPOSE OF REVIEW

The gastrointestinal tract plays an important role in the maintenance of fluid and electrolyte balance, and its diseases cause disturbances in that balance. Conversely, fluid and electrolyte disorders may disturb gastrointestinal function. The purpose of this review is to highlight some recent literature describing these interactions against a background of fluid and electrolyte physiology in normal and disease states.

RECENT FINDINGS

Gastrointestinal disease is the most common cause of fluid and electrolyte disturbance, and this can usually be corrected by the oral route, although parenteral replacement is sometimes required. The use of self-administered subcutaneous fluid and electrolyte administration at home is described. Reduced microcirculatory perfusion as a result of hypovolaemia or a rise in blood viscosity after packed cell transfusion may precipitate gut necrosis, particularly during enteral feeding. Positive salt and water balance postoperatively of as little as 3 l impairs gastrointestinal function and increases complications. Other states of salt and water retention may have similar effects, although further research is needed to define this.

SUMMARY

The role of the gastrointestinal tract in controlling fluid and electrolyte balance is underestimated. Conversely, the effect of fluid and electrolyte imbalance on gastrointestinal function is apparent, but requires more research.

Assessment of Fluids and Electrolytes

Bedside evaluation of a patient's intravascular volume status is challenging, even for the seasoned practitioner. There is no single diagnostic test to determine whether a patient is hypovolemic, hypervolemic, or euvolemic. Often, underlying or concomitant disease states, medications, and other therapeutics can make available data difficult to interpret. Therefore, a combination of clinical evaluation, laboratory studies, and other diagnostics are required to make a clinical judgment regarding volume status. Patients who demonstrate alterations in their volume status are likely to have electrolyte abnormalities as well, and assessment of serum electrolyte values and potential therapeutic interventions is a vital piece in caring for critically ill patients.

Hyponatremia in hospitalized critically ill children: current concepts

Hyponatremia (serum sodium to < 136 mEq/l) is the most common electrolyte abnormality in critically ill children. It could result from a deficit of sodium, or surplus of water. Impaired water excretion, 'inappropriate' release of vasopressin, use of hypotonic fluids, redistribution of sodium and water, sick cell syndrome, several drugs and primary illness all may contribute to hyponatremia. Acute hyponatremia, defined as a fall in serum sodium to ~ 120 mEq/l within 48 hours may result in acute cerebral edema and brain stem herniation particularly in children. However, there is paucity of data on hyponatremia in hospitalized critically ill patients. Studies addressing incidence, cause and outcome of hyponatremia in critically ill patients are needed to plan rational fluid therapy protocols, and resolve the current debate, which calls for abandonment of N/5 saline in 5% dextrose solution as maintenance intravenous fluid in favour of normal saline to prevent hyponatremia. At present it is not fully correct to assume that isotonic maintenance fluids would be superior to current maintenance fluids. Reducing the volume of maintenance fluid to about 75% of normal maintenance volume may be more appropriate way to prevent hyponatremia in view of water retaining effect of high ADH and reduced renal free water clearance in critically ill children.

Effect of intraoperative intravenous crystalloid infusion on postoperative nausea and vomiting after gynaecological laparoscopy: comparison of 30 and 10 ml kg(-1)

BACKGROUND

I.V. fluid administration has been shown to reduce postoperative nausea and vomiting (PONV). The optimum dose is unknown. We tested the hypothesis that administration of i.v. crystalloid of 30 ml kg(-1) would reduce the incidence of PONV compared with 10 ml kg(-1) of the same fluid.

METHODS

A total of 141 ASA I female patients undergoing elective gynaecological laparoscopy were randomized, in double-blind fashion, to receive either 10 ml kg(-1) (n=71; CSL-10 group) or 30 ml kg(-1) (n=70; CSL-30 group) of i.v. compound sodium lactate (CSL).

RESULTS

In the first 48 h after anaesthesia, the incidence of vomiting was lower in the CSL-30 group than in the CSL-10 group (8.6% vs 25.7%, P=0.01). Anti-emetic use was less in the CSL-30 group at 0.5 h (2.9% vs 14.3%, P=0.04). The incidence of severe nausea was significantly reduced in the treatment group at awakening (2.9% vs 15.7%, P=0.02), 2 h (0.0% vs 8.6%, P=0.04) and cumulatively (5.7% vs 27.1%, P=0.001). The numbers needed to treat to prevent vomiting, severe nausea and antiemetic use in the first 48 h were 6, 5 and 6, respectively.

CONCLUSION

I.V. administration of CSL 30 ml kg(-1) to healthy women undergoing day-case gynaecological laparoscopy reduced the incidence of vomiting, nausea and anti-emetic use when compared with CSL 10 ml kg(-1).

Acute hyponatremia related to intravenous fluid administration in hospitalized children: an observational study

OBJECTIVE

To develop hyponatremia (plasma sodium concentration [P(Na)] <136 mmol/L), one needs a source of water input and antidiuretic hormone secretion release to diminish its excretion. The administration of hypotonic maintenance fluids is common practice in hospitalized children. The objective of this study was to identify risk factors for the development of hospital-acquired, acute hyponatremia in a tertiary care hospital using a retrospective analysis.

METHODS

All children who presented to the emergency department in a 3-month period and had at least 1 P(Na) measured (n = 1586) were evaluated. Those who were admitted were followed for the next 48 hours to identify patients with hospital-acquired hyponatremia. An age- and gender-matched case-control (1:3) analysis was performed with patients who did not become hyponatremic.

RESULTS

Hyponatremia (P(Na) <136 mmol/L) was documented in 131 of 1586 patients with > or = 1 P(Na) measurements. Although 96 patients were hyponatremic on presentation, our study group consisted of 40 patients who developed hyponatremia in hospital. The case-control study showed that the patients in the hospital-acquired hyponatremia group received significantly more EFW and had a higher positive water balance. With respect to outcomes, 2 patients had major neurologic sequelae and 1 died.

CONCLUSION

The most important factor for hospital-acquired hyponatremia is the administration of hypotonic fluid. We suggest that hypotonic fluid not be given to children when they have a P(Na) <138 mmol/L.

Safe paediatric intensive care. Part 1: Does more medical care lead to improved outcome?

Neonatal and paediatric intensive care has improved the prognosis for seriously sick infants and children. This has happened because of a pragmatic approach focused on stabilisation of vital functions and immense technological advances in diagnostic and therapeutic procedures. However, the belief that more medical care must inevitably lead to improved health is increasingly being questioned. This issue is especially relevant in developing countries where the introduction of highly specialised paediatric intensive care may not lead to an overall fall in child mortality. Even in developed countries, the complexity and availability of therapeutics and invasive procedures may put seriously ill children at additional risk. In both developing and industrialised countries the use of safe and simple procedures for appropriate periods, particular attention to drug prescription patterns and selection of appropriate aims and modes of therapy, including non-invasive methods, may minimise the risks of paediatric intensive care.

Fluid and electrolytes in the elderly

PURPOSE OF REVIEW

The intake of water and electrolytes is inseparable from the ingestion of nutrients by normal or artificial means. Recent reports have agreed in criticizing the poor standards of practice and of training in the management of fluid and electrolyte balance, resulting in a large amount of avoidable morbidity, particularly in the elderly who are more vulnerable to fluctuations in body composition.

RECENT FINDINGS

Ageing is associated with impaired physiological reserve and a reduced ability to compensate for fluctuations in environmental conditions. These changes include reduced cardiac and renal reserve, making the elderly more vulnerable to changes in water and electrolyte gain or loss with a resulting increase in morbidity and mortality. The ability to cope with errors in prescriptions is correspondingly diminished. Dehydration is a common problem in nursing homes and in the community, due often to failures in detection and appropriate management. In many cases, the cause is iatrogenic due to diuretics or drugs which impair the intake of food and fluid. Salt and water overload, particularly in hospital patients, is also common and results in impaired recovery from surgery and increased perioperative mortality and morbidity. Hyponatraemia is also an important clinical problem in hospital and the community.

SUMMARY

Better training in the detection, prevention and management of fluid and electrolyte imbalance is needed to reduce common and serious morbidity associated with this problem to which the elderly are especially prone, owing to their diminished physiological reserves and increased comorbidity.