Before I Wake — Steven Spruill

HE STALKS HER IN THE SHADOWS OF SLEEP...
Night after night, Dr. Amy St. Clair is a small child again, wandering in the dark woods. A strange voice is calling her name-commanding her to look at some-thing too horrible to see. Night after night, she awakens soaked in sweat-gripped by the frightening sense that someone has been in her house.

BUT THE NIGHTMARE DOESN'T END WITH HER DREAMS.
Now, at Hudson General, where Amy is head of Emergency Services, something is very wrong. Healthy, recovering patients are dying, and Amy can't shake the feeling that their deaths are connected to the haunting dreams. Who-or what-is turning her ER into a morgue? As she struggles to unlock the chilling truth behind her nightmares, a cunning madman tugs at her relentlessly through the veil of sleep-dragging her further and further into a horrifying circle of terror and death.