Consider using a composite field for vitals like blood pressue

[fwextensions]

Postgres has a notion of composite types that might better model some vitals like blood pressure, which always has two components. Right now, those are independent columns in the database, but it never makes sense to include a systolic pressure without a diastolic one, or vice versa. This would also make it easier to have a single "BP field" component that handles entry, rather than two independent input fields.

This could also be used for temperature, if we wanted to include the selection of units with the value.

[fwextensions]

This might make sense for the SpO2 field as well, since the Room Air and O2 sub-fields only apply when the O2 saturation has been filled in.