<prompt> Normal cardiac index in an adult is5.9 Lminm22.3 Lminm23.2 Lminm24.6 Lminm2  <response>: Cardiac index: - Cardiac output per square meter of body surface area. i.e. Cardiac index Cardiac outputBody surface area Experiments have shown that the cardiac output increases approximately in propoion to the surface area of body. The average human being who weighs 70 kilograms has a body surface area of about 1.7square meters, which means that the normal average cardiac index for adults is about 3 L min M2 of body surface area. 