It is a quiet night in the ED, when at 2300, a 33 year old woman presents with copious vaginal bleeding. The bright red blood has soaked through several pads at home, and the blood is now pouring onto the stretcher.
History reveals that she is a G4P2, who delivered a 38 week male, SVD, 16 hours ago, and then left the hospital against medical advice. Her previous live child was delivered by C-section with a low transverse incision.
She had no prenatal care, is on no medications, has no allergies, and PMH/PSH is only remarkable for moderate asthma. Her last meal was at 1800.
She is speaking full sentences, and does not seem to be in any respiratory distress.
Her vital signs are:
Temp 37.7 celsius HR 125 BP 85/50 RR 28

Which of the following is the most important in the initial management of this patient?