Ok, I'm a new grad and I've worked in the ICU for 7 months and just came off orientation about a month ago. I have patients frequently on mechanical ventilation but our respiratory therapists manage the ventilator settings when changes are made. Can anyone easily explain the difference between assist/controlled and SIMV? I understand the concept behind PEEP, but what is the significance behind tidal volume, FI02 etc? I've looked up info but it remains unclear to me...I guess I need a quick review!