This baby has mild (5%) dehydration. On history the child has decreased urine output, physical exam is normal.
Appropriate therapy at this stage is oral rehydration.
References:
Colletti JE et al. The management of children with gastroenteritis and dehydration in the emergency department. The Journal of Emergency Medicine 2010; 38(5) 686-698.
Evidence on the assessment of dehydration, methods of rehydration, and the utility of antiemetics in the child presenting with acute gastroenteritis
Oral rehydration therapy and early refeeding in the management of childhood gastroenteritis
Link: CPS Website