Cyanosis in trauma is interpreted as

Cyanosis is a bluish discoloration of the skin, mucous membranes, tongue, lips, or nail beds and is due to an increased concentration of reduced hemoglobin (Hb) in the circulation. Clinically evident cyanosis typically occurs at an oxygen saturation of 85% or less. Mild cyanosis may be difficult to detect Ref: guyton and hall textbook of medical physiology 12 edition