Randomised controlled trial of intravenous maintenance fluids

Abstract

Aim: Traditional paediatric intravenous maintenance fluids are prescribed using hypotonic fluids and the weight-based 4:2:1 formula for administration rate. However, this may cause hyponatraemia in sick and post-operative children. We studied the effect of two types of intravenous maintenance fluid and two administration rates on plasma sodium concentration in intensive care patients. Methods: A Factorial-design, double-blind, randomised controlled trial was used. We randomised 50 children with normal electrolytes without hypoglycaemia who needed intravenous maintenance fluids for >12 h to 0.9% saline (normal saline) or 4% dextrose and 0.18% saline (dextrose saline), at either the traditional maintenance fluid rate or 2/3 of that rate. The main outcome measure was change in plasma sodium from admission to 12-24 h later. Results: Fifty patients (37 surgical) were enrolled. Plasma sodium fell in all groups: mean fall 2.3 (standard deviation 4.0) mmol/L. Fluid type (P = 0.0063) but not rate (P = 0.12) was significantly associated with fall in plasma sodium. Dextrose saline produced a greater fall in plasma sodium than normal saline: difference 3.0, 95% confidence interval 0.8-5.1 mmol/L. Full maintenance rate produced a greater fall in plasma sodium than restricted rate, but the difference was small and non-significant: 1.6 (-0.7, 3.9) mmol/L. Fluid type, but not rate, remained significant after adjustment for surgical status. One patient, receiving normal saline at restricted rate, developed asymptomatic hypoglycaemia. Conclusion: Sick and post-operative children given dextrose saline at traditional maintenance rates are at risk of hyponatraemia.Key words: child; fluid therapy; infusion; intravenous.Intravenous (IV) fluids have been used in paediatrics for over 50 years. The most commonly used maintenance fluid, used to replace normal expected fluid losses in situations such as fasting, is hypotonic saline with dextrose. Volumes are typically calculated using a weight-based infusion rate: for the first 10 kg, 4 mL/kg/h, for the next 10 kg, 2 mL/kg/h and 1 mL/kg/h for each kilogram thereafter.1-6 However, it may be inappropriate for those children who have non-osmotic production of antidiuretic hormone (ADH). The syndrome of inappropriate ADH 7 occurs in meningitis, 8,9 encephalitis, 10 pneumonia, 11 bronchiolitis 12 and after surgery. [13][14][15][16] Any consequent hyponatraemia may be exacerbated by hypotonic IV fluids. 14,17 Natriuresis (urinary salt loss) may cause hyponatraemia. Sodium loss and hypovolaemia occur in cerebral salt wasting (CSW), 18,19 probably caused by a hormone such as atrial natriuretic hormone.19 Hyponatraemia in neurosurgical patients may be from CSW, not the syndrome of inappropriate ADH.20 CSW occurs in children with neurological illness, neurosurgery and craniofacial surgery. 21-23Symptomatic hyponatraemia is uncommon if the plasma sodium ([Na]) is >120-125 mmol/L, 24,25 but depends on the rate of fall, 26 and can occur at higher values. 17 It can cause death or serious neurological mo...

Perioperative fluid management and postoperative hyponatremia in children

“…One retrospective, informatics-enabled study demonstrated that undergoing a surgical procedure was an independent risk factor for hospital-acquired hyponatremia [adjusted odds ratio (OR) 1.44, 95 % confidence interval (CI) 1.09-1.91]; this effect was similar to that attributed to fluid hypotonicity (adjusted OR 1.37, 95 % CI 1.03-1.84) [7]. A randomized controlled trial comparing 0.9 % saline and 0.18 % saline in a PICU population demonstrated that plasma sodium tended to decrease more in surgical patients than medical patients (-2.3 mmol/L; 95 % CI −0.46 to 0.1, P=0.057) [12].…”

“…Although the reported incidence of postoperative hyponatremia has varied from 11 to 31 % [6,8,9], nearly all studies consistently show that postoperative patients have an increased risk of developing hyponatremia [2,7,[10][11][12]. One retrospective, informatics-enabled study demonstrated that undergoing a surgical procedure was an independent risk factor for hospital-acquired hyponatremia [adjusted odds ratio (OR) 1.44, 95 % confidence interval (CI) 1.09-1.91]; this effect was similar to that attributed to fluid hypotonicity (adjusted OR 1.37, 95 % CI 1.03-1.84) [7].…”

Safety and efficacy of isotonic (0.9%) vs. hypotonic (0.18%) saline as maintenance intravenous fluids in children: A randomized controlled trial

“…Kannan, et al [13] have previously shown that hyponatremia is less common with the use of isotonic saline in standard volume (1.72%) as well as with reduced volume hypotonic saline solution (3.8%) when compared to standard volume hypotonic fluid (14.3%). Young and Keeley [14], however, reported that fluid type but not rate was significantly associated with hyponatremia in surgical pediatric patients.…”

“…Isotonic maintenance fluids have consistently been shown to lower the incidence of hyponatremia [6,[12][13][14][15][16]. Reducing the volume of administered fluid has also been shown to decrease the risk of hyponatremia in children with free-water excess [13].…”

Improving intravenous fluid therapy in children with gastroenteritis

“…It is now well established that hypotonic maintenance fluids result in hospital-acquired hyponatremia in children [8][9][10]. This has been best demonstrated in the post-operative setting where the incidence of hospital-acquired hyponatremia (sodium<135 mEq/L) is 20-30% [11][12][13][14][15]. Surprisingly, there have been no studies to evaluate the safety of the deficit-plus-maintenance-fluid approach in hospitalized children with gastroenteritis.…”