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Key Clinical Questions

  • image What are the clinical and pharmacologic effects of single agent versus multiple agent sedative and analgesic administration?

  • image What is the best way to dose sedative, analgesic, and paralytic agents in the intensive care unit (ICU)?

  • image How do the pharmacokinetics and dosing of sedative, analgesic, and paralytic agents change with duration of infusion?

  • image What is the proper sequence to initiate sedatives, analgesics, and/or paralytics, and how does dosing refinement affect time to weaning and other predictors of favorable outcome?

  • image How do you select individual sedative, analgesic, or paralytic agents in critically ill patients?

  • image When do you decide to paralyze a ventilated patient?

Our understanding of pain, agitation, and delirium (PAD) has been a journey of discovery. In 1995, the Society of Critical Care Medicine (SCCM) published the relatively modest Practice Parameters for Intravenous Analgesia and sedation for Adult Patients in the Intensive Care Unit, six recommendations based mostly on expert opinion. The American College of Critical Care Medicine subsequently developed evidence-based guidelines in 2002 and most recently in 2013.

ICU patients experience significant nonprocedural as well as procedural pain. The development of reproducible and validated tools for assessing pain, sedation, agitation, and delirium have been essential in allowing clinicians to know not only when to treat, but how effective a given treatment is. Furthermore, the recognition that pain agitation and delirium may be a risk factor for the post ICU syndrome characterized by weakness, cognitive dysfunction, and post-traumatic stress disorder (PTSD), has further underscored the importance of their early recognition and effective treatment. In the following chapter, we will review the current concepts in the assessment, treatment, and monitoring of PAD in the ICU population.


Sedative, analgesic, and paralytic therapies are administered by intravenous (IV) bolus or by IV infusion, as intramuscular and enteral titration are unreliable.

Principles of dose initiation and maintenance

Bolus dosing has the advantage of a rapid onset of action, but has the associated risk of either overshooting or undershooting the therapeutic goal. As such, nursing vigilance with frequent assessment and bolus titration to defined therapeutic outcomes is necessary. On the other hand, infusion drug dosing reflects a more gradual and refined titration to clinical effect, but does carry a greater risk of drug accumulation with protracted infusion. As such, an unwanted prolongation of time to awakening may occur when clinical circumstances allow for drug discontinuation. For this reason, infusions should only be undertaken in the ICU when bolus dosing has failed to produce the desired sedative effect.

Clinicians should follow a structured algorithm for ICU sedation, pain control, and paralysis and become familiar with the ACCM PAD guidelines (Figure 139-1). While sedative and analgesic agents help to maintain mechanical ventilation, their prolonged use can become an obstacle to liberation from life support. Because planning ...

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