Analgesia and sedation in the intensive care unit: an overview of the issues

All clinicians who provide care to critically ill patients face many daily management challenges, including ensuring patient comfort and tolerance of the intensive care unit (ICU) environment, while avoiding complications related to therapy. This seemingly straightforward task of safely maintaining patient comfort in fact requires an appreciation of the many factors that may influence the patient's state of comfort or distress and the inter-relationship with ICU-related processes.Pain is the root cause of distress experienced by many ICU patients [1-4], but anxiety, dyspnea, delirium, sleep deprivation, and other factors can contribute and are often additive or synergistic [5-8]. The predisposing and causative conditions that provoke these components of distress range widely, and include underlying medical conditions (such as arthritis or chronic pain syndrome) and acute medical or surgical illness, as well as many 'routine' aspects of critical care such as mechanical ventilation, indwelling tubes and catheters, iatrogenic illness, medication side effects, nursing interventions such as turning and suctioning, and excessive ICU noise and light [9]. Thus, improving the patient's tolerance of these common issues that contribute to a state of relative discomfort or outright distress is important [9-13].Analgesia and sedation management has routinely been employed in ICU patients for many years, particularly among those receiving mechanical ventilation [14]. Surveys of ICU practitioners indicate continued widespread use and provide insight into the diversity of approaches, including the relative frequency with which specific medications are utilized and variability in monitoring, protocol use, and other clinical practice parameters [15-25]. An international cohort study of mechanically ventilated adults conducted in 1998 [26] (48% from Europe, 24% from Latin America, and 28% from North America) provides an instructive global composite of clinical practice. Only 68% of pa