答:新生儿和未成熟儿调节水和电解质代谢的功能尚未完善,其生理特点为:体液量占体重的比例高,约为70～80%。且年龄愈小,比例愈高。其中细胞外液占40%以上,为每天的出入液量,新生儿水交换率比年长儿快一倍以上。细胞内液在胎儿期则较少,出生时约占35%。新生儿于生后4天内呈代偿性代谢性酸中毒状态,血pH7.30～7.39,CO_2结合力20～ A: Neonatal and immature children regulate water and electrolyte metabolism is not yet perfect, and its physiological characteristics are: high body fluid ratio of body weight, about 70 to 80%. And the younger, the higher the proportion. Extracellular fluid which accounts for more than 40% of daily intake and discharge, neonatal water exchange rate more than twice as fast as older children. Intracellular fluid in the fetal period is less, about 35% at birth. Neonates within 4 days after birth was compensated metabolic acidosis, blood pH7.30 ~ 7.39, CO_2 binding 20 ~