The Guidelines to the Practice of Anesthesia Revised Edition 2015 (the guidelines) were prepared by the Canadian Anesthesiologists' Society (CAS), which reserves the right to determine their publication and distribution. Because the guidelines are subject to revision, updated versions are published annually. The Guidelines to the Practice of Anesthesia Revised Edition 2015 supersedes all previously published versions of this document. Although the CAS encourages Canadian anesthesiologists to adhere to its practice guidelines to ensure high-quality patient care, the society cannot guarantee any specific patient outcome. Each anesthesiologist should exercise his or her own professional judgement in determining the proper course of action for any patient's circumstances. The CAS assumes no responsibility or liability for any error or omission arising from the use of any information contained in its Guidelines to the Practice of Anesthesia.