You may be able to find a doctor who can be on duty at your event by contacting local hospitals or medical clinics. However, in addition to having a doctor on hand, it's also a good idea to invest in medical emergency devices such as a first aid kit, automated external defibrillator (AED), and oxygen tanks. These devices can provide immediate medical attention in case of an emergency and can be operated by trained volunteers or even non-medical personnel. You can purchase these devices from medical supply stores or online retailers. By having these devices on hand, you can help ensure the safety and well-being of your guests in case of a medical emergency.