Medical question for the f'list

[sholio]

For those of you with medical backgrounds - fanfic-related question! Let's say that you have a person who is in (mild) hypovolemic shock due to blood loss and is also chilled from exposure (but not severely hypothermic). You have a pint/liter of saline with you that you could give them intravenously, but it's also chilled because it's been outside along with you, while searching for them. Is it better to do nothing and focus on warming them up, or to give them cold saline and increase their blood volume while risking dropping their body temperature further?

Or is this one of those case-by-case things?