According to Marc Colbeck, a paramedic instructor and operator of Paramedicine.com, the Fowler's position is an upright or leaning sitting position in which the knees are straight or bent. Someone in a high Fowler's position sits upright, while someone in a low Fowler's position has only a slightly elevated head.
Wikipedia explains that Fowler's position is a patient's standard position when sitting or lying down. The primary purpose of Fowler's position is to promote or improve a patient's breathing by maximizing chest expansion and relaxing the abdominal muscles. Fowler's position also helps ease chest compression for patients who are immobile.