That is why you have to make an arrangement *some days previously* with the department you have the appointment with, so they can request the control office to send a porter to you.
My neighbour does it all the time. She lets the department know a few days in advance of her need for a porter, then she gets to the main reception a bit early, phones the department who then phone the porter's control office. When her appointment is finished, she asks for a porter to be called and waits for the porter to arrive. Yes, she has to wait a while, but she does get help.
The receptionist at your local hospital should have phoned the porter's control office and asked them to send a porter for the patient who was struggling.
Porter's journeys have to be logged, for H & S reasons as well as the controller being able to direct porters to their next job, so it is understandable that they can't just wheel a patient whenever someone requests them to.
The receptionist should have known that and phoned the control office. >doh<