Anesthesiology is the medical speciality that delivers anaesthetic during surgery and other invasive operations, in critical care, and in treatment of acute and chronic pain. Through its primary competence of keeping patients safe and comfortable throughout invasive or painful operations, anesthesiology facilitates the activities of every surgical discipline and a growing number of nonsurgical disciplines as well, including complicated cardiac catheter-driven treatments. Anaesthetists have long been pioneers in patient safety, probably because of the immediacy that a mistake may bring. Hospital treatment is still risky for patients, however anaesthesia for the American Society of Anesthesiologists [ASA] physical status I and II patients having day case surgery is one of the safest and dependable procedures that a patient may have. The purpose of this study was to give a realistic framework for establishing and conducting QI programmes in anesthesiology and critical care medicine that are both scientifically sound and practicable. To reach this purpose, we discuss the science and techniques to QI, give measurements that assist assess whether QI programmes have resulted in changes, and show instances of successful QI activities