Anaesthesia has traditionally meant the condition of having sensation (including the feeling of pain) blocked or temporarily taken away. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience. General anaesthesia can depress ventilation, determining variations in pulmonary mechanics and alteration of gas exchange, often related to underlying anatomical and physiological status. The authors of this book describe the mechanisms responsible for the impairment of intraoperative respiratory function and discuss several aspects of mechanical ventilation that can be employed to improve patients' outcome. Furthermore, the administration of IV fluid is a part of carrying out a good anaesthesia. This book examines whether perioperative fluid management could change the outcome for patients undergoing procedures involving anaesthesia. The possible extra-cardiac indications of beta-blockers during the perioperative period is explored as well. Other chapters in this book examine the effect of high remifentanil doses in patients with brain tumours, the use of multivariable fuzzy logic and self-organising fuzzy logic controller structure to control anaesthesia, the different modalities of anaesthesia techniques for gastrointestinal diagnostic procedures performed in children, and an analysis of the poly-alert system for cardiovascular changes during anaesthesia.