AboutNeal Okerson Expertise I should be able to answer most questions about anatomy and physiology of heart and lungs. I also enjoy answering questions about understanding diseases. I should also be able to explain the goals and objectives of various pulmonary related treatments. Not an M.D., but worked in the field (Certified Respiratory Therapy Technician) since 1990. Registered Respiratory Therapist since 1995. B.S. degree in Health Education (1987). Currently working (since 1993) as the Director of Clinical Education in an AMA approved Respiratory Care Program in Western KY.
Question Hi Neal,
I am wanting to implement an fiO2 controller in a patient monitor, but I do not understand very well yet, how fio2 is calculated. The controller is supposed to be used e.g. in NICU and the aim is to adjust the fio2 according to spo2 steady measurements. I don't know wether the fio2 calculation depends on the ventilation method, but I would like to know how I can concretely calculate it. For example, why is the normal fio2 anybody breaths 0,21 (21%) ?
Greeting,
Franck (Germany)
Answer Franck,
Sorry for the delay in answering your question!
FIO2 is changed by adjusting a blender. The blender feeds air and oxygen into a mixed stream giving the prescribed percent of oxygen. It seems to me that you would be better off simply using input from an FIO2 analyzer. Then you have documented values instead of a guess. I haven't noticed any digital blenders. They may exist, but I am not aware of any at this time. Getting a digital input from a manual blender might be challenging? That's too far from my area.
Room air is 21% oxygen that's where we start. Adding increasing amouts of oxygen increases the FIO2. A blender is the only device that will do this and provide enough flow for ventilation.
