 Despite the importance of patient comfort during NPPV, physicians infrequently use sedation or analgesic therapy during NPPV, primarily due to concerns about the respiratory depressant effects of most of the sedatives e.g., benzodiazepines and analgesics e.g., opioids that are currently available. In addition, neither the benzodiazepines nor opioids are easily titratable, can easily accumulate and can be associated with both the development of delirium and a withdrawal effect. 