I understand the hesitation to begin a new aspect of care, especially if you believe that there has not been adequate training and/or there are not clearly defined (and evidencce based) policies and procedures in place.
Is your office staff currently providing IV infusions of other medications? If not, has there been an opportunity to brush up on IV start skills, current equipment, fluid recommendations and medication compatibilities, etc? This may be a good starting point.
If you are already skilled and current on IVs in general, then specific training on this particular medication is in order: Targeted patient population, indications and contraindications, mechanism of action, anticipated effects, side effects (and management of them), safety considerations, post-infusion care, discharge instructions & follow-up.
Next comes training on the actual procedure itself. Run thru a mock set-up. How will the medication be supplied? Will you use pre-mixed stock (highly preferable), or will 2 nurses have to prepare and sign the mixture (high risk for error)? Will you establish a primary IV with a running fluid, or start a saline-lock? Will you use an infusion pump with free flow protection, or a syringe pump? One or the other is a must to prevent inadvertent overdosing, which is probably the greatest risk. What is the protocol for vital signs (and O2 sats) pre, during & post procedure? What other medications (if any) will be part of this protocol and how will they be administered? Will there be a dedicated flow sheet (or page in the EMR) to document this care, or must the nurse write narrative notes? How long is the recovery period before the patient may be discharged? Must s/he have an escort, or be allowed to leave/drive home alone?
In the unlikely event of a serious adverse reaction, what is the mechanism for summoning help and who will respond? Do you have an emergency or code team within your office, or are you part of a larger medical center campus with a team that will respond to office emergencies? Must there be a physician/APN in office at all times during MgSo4 infusions, or can they be given when the office is staffed with nurses and support staff only? What is the role of medical office assistants in this procedure, if any?
Then comes the actual integration of this care into your office setting. How will these patients be scheduled? How will staff be assigned? How much time should be blocked for this patient? Where will this service be provided? Do you have a dedicated "infusion" room that will be consistently stocked with all of the necessary supplies and emergency items? I can tell you from OB experience, when "misadventures" occur during potentially high risk procedures, it is often because someone decided that it was "no big deal" to do said procedure in a location other than a dedicated, well-stocked procedure room. When something untoward happens, the necessary suplies are not available at one's fingertips and the **** hits the fan.
I agree with the other posters that this service can be provided in the office setting, but recognize and agree with your well placed concerns that adequate training and preparation must come first. I think we all have been unnecessarily put in bad situations because of other people's bad planning, or complete lack thereof. Good for you for trying to avoid that here!