A twenty-six-year-old is admitted for observation after a fall from a ladder. Two hours in, the heart rate has drifted from 78 to 116, the client is restless and asking repeatedly what time it is, and the skin is cool to the touch. Blood pressure is 116/78 mmHg — very nearly what it was on admission. That blood pressure is the reason clients die of this condition on observation units. In hypovolemic shock, a maintained blood pressure does not mean the client is stable; it means compensation is still working. The body defends pressure ferociously by constricting vessels and speeding the heart, and it can do so through a substantial loss of circulating volume. When pressure finally falls, compensation has been exhausted, and the client is much further along than the number suggests. Hypovolemic shock is a state of inadequate tissue perfusion caused by loss of circulating volume — blood, plasma, or water and electrolytes. The nurse's contribution is almost entirely about earliness: recognizing compensation while it is still working, escalating on the trend rather than the threshold, and then...