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Intensive care specialists have become increasingly more interested in
the prevention and treatment of physiologic and psychological stress in
critically ill patients1–3 in order to prevent
detrimental consequences ranging from systemic inflammatory response
syndrome,4 to cardiac complications,5,6
to posttraumatic stress disorder.7–9 Studies have
addressed the questions of an optimal sedation regimen and several
evidence-based guidelines and strategies have been published.10–14 The analgesic component for sufficient stress relief, however,
has not been addressed extensively, and few recommendations, primarily based
on individual clinical practices, are currently
available.15
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In view of the side effects of opioids, especially respiratory
depression, altered mental status, and reduced bowel function, regional
analgesia utilizing neuraxial and peripheral nerve blocks offer significant
advantages. The lack of a universally reliable pain assessment tool
(“analgesiometer”) in the critically ill contributes to the dilemma of
adequate analgesia. Many patients in the critical care unit are not able to
communicate or use a conventional visual or numeric analog scale to quantify
pain. Alternative assessment tools derived from pediatric16–18 or geriatric19 practice that rely on grimacing
and other physiologic responses to painful stimuli might be useful, but have
been inadequately studied in the intensive care unit (ICU). Changes in heart
rate and blood pressure in response to nursing activities, dressing changes,
or wound care can also serve as indirect measurements of
pain,20 and sedation scores like the Ramsey or Riker and
colleagues21,22 scale might be helpful, although not
specifically designed for pain assessment.
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The objective of this chapter is to describe the indications, limitations,
and practical aspects of continuous regional analgesic techniques in the
critically ill based on the available evidence, which at the moment is
limited to case reports, cohort studies, expert opinion, and extrapolation
from studies looking primarily at intraoperative use of regional anesthesia
extending into the postoperative ICU stay. The evidence level of our
recommendation is therefore mostly grade C and D according to the “Grades
of Recommendation” published by the Oxford University Centre for Evidence
Based Medicine (http://www.cebm.net/index.asp).
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Epidural analgesia is probably the most commonly used regional
analgesic technique in the ICU setting.23 Some
indications, in which epidural analgesia may not improve mortality rates but
facilitates management and improves patient comfort in the ICU, include chest
trauma,24–27 thoracic28,29 and
abdominal surgery,5,30,31 major vascular
surgery,32,33 major orthopedic
surgery,34 acute pancreatits,35
paralytic ileus,36–39 cardiac
surgery,40,41 and intractable angina
pain.42,43 Although high-risk patients seem to profit most
from epidural analgesia,44,45 the current literature does
not address the specific circumstances of the critically ill patient with
multiple comorbidity and organ failure. For that reason, an individual
approach is necessary when considering application of epidural analgesia in
this population.46
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In a survey of 216 general ICUs in England, ...