Learn Italian: Essendo la necessità urgente, il medico ha deciso di intervenire. - The necessity being urgent, the doctor decided to intervene.

In an absolute gerund clause (where the gerund has a different subject from the main sentence), the subject almost always goes immediately after the gerund. If you put it before (La necessità essendo urgente...), it sounds unnatural in Italian. Placing it after clearly signals to the listener that this introductory clause has its own independent subject.

Does essendo just mean 'being' here, or does it imply a specific relationship to the main sentence?

While it literally translates to 'being', this absolute gerund construction usually carries a strong causal meaning. It acts as an elegant, slightly formal way of saying 'Since the necessity was urgent' (Poiché la necessità era urgente) or 'Because the necessity was urgent' (Dato che la necessità era urgente).

Why do we use the preposition di in ha deciso di intervenire?

The verb decidere (to decide) requires the preposition di when it is followed by an infinitive verb. You will always use the pattern decidere di fare qualcosa (to decide to do something). This is a great fixed verb-preposition pair to refresh and memorize!

Could I use dottore instead of medico here?