A forced air warming blanket for providing conditioned gas to a patient and a method of using and manufacturing the same. The forced air warming blanket comprises a first blanket portion which comprises a generally U-shaped inflatable region, at least part of the external surface of the inflatable region being air permeable, as well as an inlet port for receiving temperature conditioned gas. An inner blanket portion is provided within the generally U-shaped inflatable region of the first blanket portion. The inner blanket portion is at least partially (or wholly) detachable from the first blanket portion. The inner blanket portion may also have an inflatable region. An outer blanket portion may be provided.