1.
Body fluid composition.
Jain, A
Pediatrics in review. 2015;(4):141-50; quiz 151-2
Abstract
UNLABELLED Body fluid composition is maintained in a normal physiologic range by regulatory mechanisms that control sodium and water metabolism. A detailed knowledge of the homeostatic mechanisms will help in understanding the pathogenesis and management of disorders of sodium and water balance. OBJECTIVES After completing this article, readers should be able to: 1. Understand the distribution of fluid and solute in different body compartments. 2. Demonstrate the homeostatic mechanisms involved in maintaining sodium and water metabolism. 3. Calculate osmolality and recognize the clinical importance of maintaining osmotic equilibrium. 4. Recognize common disorders of hypernatremia or hyperosmolality and evaluate and understand the role of calculating free water deficit in the treatment of these disorders. 5. Recognize common disorders of hyponatremia or hypo-osmolality, appreciate the role of urine sodium and urine osmolality in evaluation,and understand the importance of slow correction of these disorders.
2.
Basic principles and practical steps in the management of fluid balance in the newborn.
Hartnoll, G
Seminars in neonatology : SN. 2003;(4):307-13
Abstract
The fluid management of newborn babies can pose many problems. This article discusses the factors that affect fluid balance in the newborn infant, both term and preterm, and the special circumstances of the surgical neonate. The main determinants of management are: (1) an estimation of transepidermal water losses; (2) an awareness of glomerular filtration rate and how this is influenced by age, respiratory distress and medical intervention; and (3) knowledge of tubular function and its maturation and the processes of postnatal adaptation. This knowledge and appropriate monitoring are the mainstay of management of neonatal fluid balance.
3.
Volume expansion during neonatal intensive care: do we know what we are doing?
Evans, N
Seminars in neonatology : SN. 2003;(4):315-23
Abstract
Although volume expansion is liberally used in newborn intensive care, we know little about its effects on hemodynamics or outcomes. Given appropriately to a truly hypovolemic baby, it can be life-saving, but the clinical diagnosis of hypovolemia is probably very inaccurate. We know that volume expansion has less effect on blood pressure than dopamine, and although it seems to produce immediate increases in systemic blood flow, we do not know for how long these increases are sustained. There is evidence to show that the routine use of volume expansion in preterm babies has no effect on outcome, and there is little evidence to support its routine use during resuscitation or the treatment of metabolic acidosis. Whether crystalloids or colloids are preferable is also unclear in newborns. In situations of concern related to circulatory compromise, if possible, define the hemodynamics echocardiographically. Otherwise, if in doubt, some volume should be given, although it is probably unwise to keep expanding the volume if this is not improving physiologic (blood pressure and heart rate) or echocardiographic systemic blood flow parameters.