Ambulances come in a variety of vehicle types and configurations, according to Dr. Ben Weston, an assistant professor at Medical College of Wisconsin. There's the familiar minivan style, but other ambulances have a pickup-truck chassis with an attached patient compartment. Inside, ambulances carry an assortment of lifesaving equipment. They carry portable oxygen supplies and masks, cervical collars, slings, backboards to protect patients with spinal injuries, and kits with towels, dressings, scissors, clamps and sterile gloves to use in delivering babies. Among other equipment, they’re also equipped with disinfectant shoe covers, coveralls and other gear for controlling exposure to infections. One of the most important — and costly — pieces of equipment on an ambulance is the heart monitor. "It's one of the essentials," Buchle says. The device is capable of doing an electrocardiogram (EKG), and also transmitting the readings via wireless modem to a doctor at the hospital while they are in route. Additionally, the device can check oxygen levels and blood pressure, and even act as a pacemaker for patients whose hearts need such assistance. Ambulances also carry supplies of medications, with state regulations determining what they're allowed to have. Ambulances can carry an extensive assortment of drugs, from various cardiac medications and drugs to treat patients who’ve suffered allergic reactions or asthma attacks. There also are various pain medications, ranging from aspirin to fentanyl. Another useful piece of equipment on ambulances these days is a laptop computer, which crews can use to receive detailed information from the 911 dispatcher. That enables them to be better prepared when they arrive on the scene.