After a pulmonary embolism, if it is an acute and extensive embolism and not treated promptly, it can lead to severe hypoxemia. If hypoxemia is not addressed quickly and persists, it will affect the oxygen supply to vital organs throughout the body, including the brain. The brain is the organ most vulnerable to oxygen deprivation. If there is complete lack of oxygen for just four minutes, irreversible damage occurs to the cerebral cortex, and the patient will not wake up, leading to a vegetative state. Therefore, in cases of acute extensive pulmonary embolism, if treatment is delayed, there is a significant risk of the patient entering a vegetative state, and the mortality rate is also very high. Many patients may experience sudden death.