An Anesthesiologist is a medical doctor who assesses the medical risks of patients undergoing invasive surgical, obstetric, therapeutic, and diagnostic procedures and optimizes the patient's condition prior to, during, and after the procedure monitoring the body's vital functions, such as breathing, heartbeat, circulation, temperature, and consciousness. An anesthesiologist may administer drugs that numb the local area of the body where a procedure is being performed (regional anesthesia) or alternatively, ensure a person is completely unconscious and pain-free during a procedure (general anesthesia).

Anesthesiologists can further specialize in areas such as critical care medicine, pain management, obstetric anesthesia or hospice and palliative care. The specialist may be called to act in initiating direct resuscitation in the care of emergency patients with cardiac or respiratory emergencies, severe injuries or any other condition requiring artificial ventilation. An Anesthesiologist who specializes in Pediatric Anesthesiology provides the same services for neonates, infants, children, and adolescents including Neonatal or Pediatric Intensive Care Units (NICU or PICU).