There is no set structure for each algorithm, much like an emergency physician will approach each chief complaint (Chest pain, Syncope etc.) differently. While each algorithm is structured based upon how an emergency physician thinks about each complaint, there are some general guidelines. The primary boxes in black ask general questions about the complaint, usually starting with ABCs and primary resuscitation. The secondary boxes in gray expand on questions from the primary boxes. For many complaints, you rule out life-threatening disease processes using the History & Physical. These aspects are portrayed in the boxes with the darkened outline. At certain points throughout the algorithm there are numbers in brackets. These refer to the numbers on the accompanying text page that will expand on that item. For example, in the vaginal bleed algorithm, the number [4] next to the (+) Ectopicrefers to the ultrasound findings in ectopic pregnancy and statistics. The text page includes evidence-based explanations along with encountered pitfalls. The goal of the algorithms is to provide a basic framework upon which to build. It starts with a very simple broad algorithm but allows the reader to delve into controversial evidence-based decisions.