الفهرس 
PATHOPHYSIOLOGY OF PAINOnly 14 pages are availabe for public view
 |  | from | 129 |  |  |
| | | from | 129 | | |
Abstract
Pain control is the primary concern of patients
scheduled for surgery to obtain an optimal outcome after
surgery.
The stress response consists of complex neurohumoral ,
immune response to injury and associated with hormonal /
metabolic response. Stress response saves the body from lifethreatening
injury, but it may need to be controlled with
medications or other techniques to keep it from causing new
illnesses or complications.
Pre-emptive analgesia involves the introduction of an
analgesic regimen before the onset of noxious stimuli, with the
goal of preventing sensitization of the nervous system to
subsequent stimuli that could amplify pain. It works by
through reducing the nociceptive input (Minimally invasive
surgery, LA, NSAIDS, Opioids), attenuating transmission
(Blocks, Spinal, Epidural) and modulate mechanisms that
underlie sensitization (NMDA blockade, Opioids).
Patient controlled analgesia (PCA) offers potential
unique benefits (reliable analgesic effect,improved patient
autonomy,flexible adjustment to individual needs, etc) whether
or not they truly offer significant clinical advantages as the
overall effectiveness of any analgesic technique depends on
Summary
103
both the degree of pain relief that can be achieved and the
incidence of side effects or complications.
Pain neurobiology is a complex of dynamic interrelated
systems and unimodal analgesia cannot be sufficient to
provide optimal pain management so multiple modes should
improve outcome by its additive & synergistic effects of
actions. Multimodal pain management principles through
action on multiple sites, multiple mechanisms, avoid opioid
dominance, multimodal lower doses of used drugs to reduce
adverse effects, prevent toxicity of drugs .
Epidural analgesia is considered as the gold standard
analgesic technique for major surgery. It has the potential to
provide suitable patients with complete dynamic analgesia for
as long as the epidural is continued. Spinal analgesia and nerve
blocks offer simplicity, yet efficacy remain an issue (work best
supplementing other analgesic techniques).
IV opioids form the cornerstone of perioperative
analgesia with excellent results. However, IV opioids may
cause pruritis, nausea and vomiting, urinary retention and
respiratory depression.
Nonsteroidal anti-inflammatory drugs (NSAIDS) and
cyclooxygenase (COX) inhibitors were initially promising, yet
serious questions persist regarding safety (alteration in gastric
Summary
104
mucosal barrier and renal tubular function, inhibition of
platelet aggregation, wound infection and thromboembolic
complications).
Alpha adrenergic agonists may enhance postoperative
analgesia and hemodynamic stability (potentially decreasing
myocardial ischemia) yet may cause excessive postoperative
sedation and aggravate postoperative hemodynamic instability
via bradycardia or decreased systemic vascular resistance.
Other potentially useful adjuvants used as apart of
perioperative multimodal analgesia including benzodiazepines,
propofol, N-methyle –D-aspartate receptor antagonist,
corticosteroids, anticonvulsant drugs,antidepressant drugs and
local anesthetic infiltration .
Perioperative analgesia is very important to improve
patient comfort, decrease somatic & autonomic responses to
airway manipulation, improve hemodynamic stability, lower
requirements for inhaled anesthetics, decrease postsurgical
organ dysfunction & complication, early recovery and
decrease hospital stay