Hypovolemic shock: recognition and first response

Hypovolemic shock is inadequate tissue perfusion from a circulating volume that has been lost — to hemorrhage, seen or hidden, or to fluid leaving the vascular space through vomiting, diarrhea, burns, diuresis or third-spacing — and it is recognized before the blood pressure falls, in the body's compensation for the loss: a rising heart rate, a narrowing pulse pressure, cool pale clammy skin, restlessness, anxiety and thirst, and a falling urine output, because vasoconstriction holds the pressure until a large share of the volume is already gone; so the nurse who sees that pattern acts on it without waiting for hypotension — stopping the loss where it can be stopped, with direct pressure on a bleed taking precedence over everything else, laying the patient flat with the legs raised, giving oxygen, securing large-bore intravenous access, starting the volume replacement and calling the team — and keeps looking for the loss that cannot be seen, because the abdomen, the pelvis, the thigh and the gut can hold a lethal volume without a drop reaching the outside.