The study of procedural sedation and analgesia has experienced significant development recently. As specific procedural sedation and analgesia agents have been developed and introduced into clinical practice, safety and efficacy studies have been conducted. The principle difficulty in conducting these studies has been the relatively low frequency of traditional outcome measures. As procedural sedation and analgesia research has expanded, measurement techniques have been refined to allow for precise comparisons between smaller groups of subjects to improve the capacity to compare these procedures. We have used capnography, bispectral EEG analysis, and subject perceptions of pain and recall as surrogate predictors of adverse events in order to compare agents and procedural techniques in procedural sedation and analgesia.