A 35 year old teacher underwent arthroscopic knee surgery after tearing a meniscus following a ski accident. She has been walking on crutches since returning home from the hospital, but is finding it very challenging to get around. It is the summer holidays and she has been enjoying laying in the sun and getting caught up on some novels. One week after her surgery she becomes quite concerned when she develops some chest discomfort that seems worse when she takes a breath in. At first she thinks she has pulled a muscle, but after a day, the pain has gotten worse and she has noticed a feeling of her heart racing. When she noticed some blood in her sputum, she asks her husband to take her to the ER.