A thermal blanket of the Augustine type includes an inflatable covering with a head end, a foot end, two edges and an undersurface. The covering is inflated through an inlet by a thermally-controlled inflating medium. An aperture array on the undersurface of the covering exhausts the thermally controlled inflating medium from the covering. Exhaust port openings are provided at the edges of the covering to vent the inflating medium, which enhances circulation of the thermally-controlled medium through the cover toward the periphery of the thermal blanket. A pair of uninflatable drape sections are provided at the head end for covering the chest area and enabling viewing thereof. When inflated, the thermal blanket self-erects and provides a bath of thermally-controlled inflating medium to the interior of the erected structure. When the structure covers a patient, the uninflatable transparent section at the head end provides a relatively unobstructed view of the sides of the patient's chest and upper torso.