The patient, who has suffered from vomiting and diarrhea for one week has hypotension and tachycardia. This patient is likely dehydrated and requires a liter of normal saline intravenously as quickly as possible. Severe hypotension is treated with vasopressors such as norepinephrine or dopamine; however, these are not appropriate initial interventions. Intravenous atropine is used to treat bradycardia; therefore, this is not appropriate for the tachycardic patient.