Chapter 150: Diagnosis and Treatment of Pain, Agitation, and Delirium in the Intensive Care Unit

Introduction

The large majority of patients in intensive care units (ICUs) experience pain, agitation, or delirium at some point during their critical illness. During the last two decades, tremendous growth in knowledge regarding the assessment and management of these syndromes in the ICU has prompted important changes in the practice of intensive care medicine. Validated tools now exist that allow clinicians to quickly and reliably evaluate patients for pain, assess their level of consciousness, and detect delirium. These assessments, in turn, guide clinicians as they choose and titrate therapies targeted to best manage a patient's symptoms. Novel strategies to address pain, agitation, and delirium have also recently been investigated. The use of validated tools to diagnose these important clinical issues using evidence-based management strategies has been shown to improve both short- and long-term outcomes in numerous studies. This chapter reviews these assessment tools and presents best practices for management in critically ill patients.

Pain in the Critically Ill

Critically ill patients frequently suffer from pain.^1,2 Whereas effective treatments for pain are widely available, detecting pain in those critically ill patients who are unable to report it is challenging. Prolonged pain in the critically ill is associated with adverse physiologic effects.³ Because analgesia is most effective when pain is identified and treated early, clinicians should frequently assess patients for pain and treat it when identified.⁴

Assessing Pain in the Critically Ill

Pain is subjective in nature; therefore, a patient's self-report (using numeric scale or visual analog scale) is an easy and reliable method to determine its presence. In fact, the 2013 Society of Critical Care Medicine (SCCM) clinical practice guidelines on the management of pain, agitation, and delirium in the ICU suggest that the numeric rating scale be used to assess pain when patients are able to self-report.⁵ Among the critically ill, however, self-reporting is not always possible due to the presence of endotracheal tubes, sedation, or delirium. Therefore, several instruments have been developed and validated to aid clinicians in identifying the presence of pain in critically ill patients.

The two most widely studied pain assessment tools for use in patients in the ICU who are unable to report pain are the Behavioral Pain Scale (BPS) and the Critical Care Pain Observation Tool (CPOT).^6,7 Both the BPS and CPOT utilize nonverbal cues and patient behaviors commonly indicative of the presence of pain; these include facial expressions, body movements, and compliance with mechanical ventilation to establish the presence of pain (Table 150-1A,B). Alternatively, a patient's surrogate may be able to provide description of behaviors indicative of pain in a particular patient, based on the surrogate's prior knowledge of the patient.⁸ Finally, in the case where the clinician is unsure if a patient is having pain, a trial of an analgesic medication ...