a mother brings her 6-month-old infant to the emergency room. the child has been vomiting since morning and has had diarrhea starting the day before. her temperature is 101.4 f, pulse 140, and respiratory rate 38. she has lost 13 oz since her well-child visit 4 days ago. her current weight is 7.6 kg. she cries before passing a bowel movement. she will not breastfeed today. what is the priority nursing diagnosis?