Classification of decompression sickness Decompression sickness is classified as follows: Type I: Involves joints, skin, and lymphatics and is milder and not typically life threatening Type II: Includes neurologic or cardiorespiratory involvement, which is serious, is sometimes life threatening, and affects various organ systems The spinal cord is especially vulnerable; other vulnerable areas include the brain, respiratory system (eg, pulmonary emboli), and circulatory system (eg, heart failure, cardiogenic shock).