| ORN | operating room nurse; orthopedic nurse |
|---|---|
| ORT | object relations technique; operating room technician; oral rehydration therapy |
| PDR | pediatric radiology; peripheral diabetic retinopathy; Physicians' Desk Reference; postdelivery room;... |
| RH | radiant heat; radiation hybrid; radiological health; reactive hyperemia; recurrent herpes; regulator... |
| rm | remission; room |