An emergency vehicle, such as an ambulance or a similar ground vehicle, was used for transporting injured or sick patients to a hospital.
In 2373, when Tom Paris was injured in the Akritirian prison and Harry Kim tried to get Zio to help him, the Akritirian sarcastically told Kim, "Of course, we'll call an emergency vehicle and rush him to a hospital." (VOY: "The Chute")