Final answer:
Subcutaneous emphysema is the abnormal finding described. It is characterized by air leaks from the respiratory system into the tissues under the skin, causing a popping or vanishing sensation when palpated. Medical attention is necessary.
Step-by-step explanation:
The abnormal finding described in the question is subcutaneous emphysema. Subcutaneous emphysema occurs when air leaks from the respiratory system into the tissues under the skin. This can cause a characteristic popping or vanishing sensation when palpated. The presence of jugular vein distension, cool, clammy skin, and other symptoms described suggest a potential underlying condition such as a collapsed lung (pneumothorax) or a ruptured lung condition like spontaneous pneumothorax. Immediate medical attention is necessary.