A dramatic four car crash on Highway 97 snarled traffic for hours and sent two people to the hospital.  Yesterday afternoon's head-on collision also almost involved a Deschutes County Sheriff's patrol car.  Deschutes County Sheriff's officials say it happened shortly after 4 on Highway 97 just north of O'Neil Highway near Redmond.  Shortly after the crash, News Channel 21 spoke to Traci Cooper with the Redmond Fire Department:  "Typically when we have someone flown, that means its pretty serious injuries.  In the four vehicles we had two injured persons: one transported by medic the second just recently was flown out by Life Flight."  The Sheriff's deputy who was almost struck, instead became a witness.  Officials say it appears it was caused when Robert Lorenzen, 22, of Madras crossed over the center line and struck two vehicles head-on.  Lorenzen had to be cut from his vehicle and he was taken by Life Flight to St. Charles Bend.  Another driver, Clyde de Moisy, 57, of Bend was taken by ambulance.  They both have non-life threatening injuries.