1.   She recovered completely, but we would like to know what causes a pulmonary embolus and how it can be prevented.

2.   A common trigger of pulmonary emboli in otherwise healthy people is sitting in one position for a long period of time, for instance on a long airplane trip.

3.   Doctors then determined Quayle had a blood clot in a lung, a condition known as a pulmonary embolus, which can be fatal if not treated quickly.

4.   Former President Nixon experienced phlebitis and a pulmonary embolus.

5.   He did not cough up blood, which can also result from a pulmonary embolus.

6.   On Monday, Quayle experienced pleuritic chest pain, which occurs on breathing and which often occurs with a pulmonary embolus.

7.   Still, not all pulmonary emboli show up on these tests.

8.   Then, Kovalsky was told that what was initially diagnosed as asthma was bilateral pulmonary emboli, or blood clots in her lungs.