++
Patients with severe medical conditions who undergo surgery are at a
higher risk for perioperative morbidity and mortality. These patients have
limited physiologic reserves, which may be overwhelmed by the perioperative
stress from the trauma of surgery. The use of perioperative regional
anesthesia and analgesia may attenuate detrimental perioperative
pathophysiology and potentially diminish the incidence of adverse patient
outcomes including mortality and major morbidity.1–4
Because only limited data are available on the effect of perioperative
peripheral anesthesia and analgesia, this discussion, like much of the
available data, focuses on the perioperative use of neuraxial, particularly
epidural, anesthesia and analgesia. Nevertheless, the general concepts
behind the benefits of perioperative neuraxial anesthesia and analgesia may
ultimately be applicable to peripheral anesthesia and analgesia.
++
In general, perioperative regional anesthesia and analgesia (as opposed
to general anesthesia followed by systemic opioids for postoperative pain
control), especially that using a local anesthetic-based solution, can
provide superior analgesia and attenuate adverse perioperative
pathophysiology, particularly the neuroendocrine stress response. These
benefits potentially can translate into decreased incidence of morbidity and
mortality and to improved convalescence. Curiously, however, trials did not
consistently document an improvement in these outcomes with the
perioperative use of regional anesthesia and analgesia. Although some data
support the use of perioperative epidural anesthesia and analgesia to
decrease postoperative pulmonary, gastrointestinal, and cardiovascular
complications,2–6 whether regional anesthesia is
superior to general anesthesia in decreasing mortality is still
controversial. Recent trials provide both supporting1 and
refuting2,7 evidence. The various methodologic differences
and problems present in available trial results influence both the
interpretation and applicability of the trial results.8
++
A wide range of detrimental physiologic effects, such as the
neuroendocrine stress response, hypercoagulation, immunosuppression, and
impaired gastrointestinal and pulmonary function, occur as a result of
surgical trauma. These effects contribute to the development of
postoperative mortality and morbidity. Many of these adverse
pathophysiologic responses begin in the intraoperative period and continue
into the postoperative period, although the precise overall contribution of
each period (intraoperative vs postoperative) to postoperative morbidity and
mortality has not been fully evaluated. In a sense, these divisions
(intraoperative vs postoperative) are artificial because most of these
pathophysiologies follow a continuum from the intraoperative to
postoperative period. However, elucidating the exact pathophysiology and
differential contribution to postoperative morbidity and mortality would
allow optimization of perioperative regional anesthesia and analgesia since
different pathophysiologies will exhibit different peaks for the development
of complications. For instance, the perioperative hypercoagulable state
begins in the intraoperative period,9 but the majority of
thromboembolic events occur well into the postoperative period. Likewise,
the incidence of other complications, such as myocardial infarction and
delirium, often peak in the postoperative period (eg, second or third
postoperative day).10–12
++