An 85 yr old lady with history of fracture neck of femur, during GA under halothane anesthesia for internal fixation of fracture suddenly develops severe hypotension, bradycardia, capnogram shows sudden fall end tidal carbon dioxide, and most probable diagnosis is:-
Myocardial infarction
Pulmonary thromboembolism
Hypothermia
Massive blood loss
Anaesthesia Q Bank