Chapter 135. Analgesia, Paralytics, and Sedation

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

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

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

4. 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?

5. How should a hospitalist select individual sedative, analgesic, or paralytic agents in critically ill patients?

6. When should a hospitalist decide to paralyze a ventilated patient?

The appropriate delivery of critical care to patients in the intensive care unit (ICU) requires a judicious use of sedative and analgesic regimens for many patients as well as the occasional need for neuromuscular blockade. Providers utilize various sedative-analgesic strategies to accomplish this goal, and pharmacologically induced paralysis may be undertaken in upwards of 10% of specific ICU populations. While management of the discomfort of mechanical ventilation serves as the primary indication for most sedative and analgesic regimens in the ICU, the increased myocardial oxygen consumption as well as immunosuppression resulting from catechol upregulation also represent important untoward outcomes to aggressively manage by treating pain and anxiety with analgesic and sedative medications.

Critically ill patients are subject to adverse stimuli that arise not only from endotracheal support apparatus, but also from indwelling monitoring lines and catheters and from surgical and other wounds. Sleep deprivation and encroachments on personal modesty also provoke further intolerance of the ICU environment. The significant discomforts of the ICU setting may be palliated with the use of sedative and analgesic therapy.

Dosing Principles

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 Maintenence

Bolus dosing has the advantage of a rapid onset of action, but has the associated risk of either over- 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 (Figure 135-1). While sedative and analgesic agents help to maintain mechanical ventilation their prolonged use can become an obstacle to liberation from life support. Because planning for weaning should occur as soon as ventilatory support is begun, the sedative and ...