These recommendations are based upon the best information available as of August 2011. They are
designed to provide information and assist decision making. They are not intended to defi ne a standard of  care, and should not be construed as one, nor should they be interpreted as prescribing an exclusive course of  management. Variations in practice will inevitably and appropriately occur when clinicians take into account  the needs of individual patients, available resources, and limitations unique to a setting, an institution or type  of practice. Every health-care professional making use of these recommendations is responsible for evaluating  the appropriateness of applying them in the setting of any particular clinical situation.