In general it is safe to have a rhinoplasty and breast augmentation at the same time. It is the standard of care for your Plastic Surgeon to use prophalactic (preventative) antibiotics perioperatively so the chance of infection is small. There may be a theoretical advantage to first do the rhinoplasty, then re-prep, drape, change gowns and gloves and instruments for the Breast Augmentation.
Performing both Rhinoplasty and Breast Augmention is safe as a combination procedure if you do the following 5 things-1. you are a Board- Certified Plastic Surgeon and trained and have expertise to do both2. Perform them in less than 5 hours3. Done in an accredited Outpatient Surgical Facility with a MD or CRNA for anesthesia4. Use separate OR preps and separate OR instruments5. Sequence is not important but I do the breast augmentation first and then the rhinoplasty - I give another dose of intraoperative antibiotics 30 minutes before beginning the rhinoplasty as some patients can have a bacteremial with rhinoplasty especially if one is doing a signficant amount of internal/septal work as wellThe Key is to be safe and be able to deliver a good patient outcome when combining any cosmetic procedures.