Sedation and Analgesia

Analgesia and sedation are primarily indicated to prevent self-harm and ensure the comfort of a patient. This chapter provides information on clinical pharmacology and medications for sedation and analgesia. Context-sensitive half-time (CSHT) is often different from the elimination half-time and explains differences in duration of effect that exist based on how long an infusion is running versus the effect we see with a single bolus dose of a medication. The CSHT also explains why medications take longer for their effects to wear off after longer infusions. Accordingly, we see that a medication like remifentanil which has virtually no CSHT will wear off in a few minutes regardless of the administration duration, while midazolam may take days after a sufficiently long infusion. Two methods have been well validated for monitoring sedation levels with equivalent results: the Richmond Agitation-Sedation Scale and the Riker Sedation-Agitation Scale.