This document discusses preemptive analgesia, which aims to prevent central sensitization and reduce postoperative pain by administering pain medication before surgery. It defines preemptive analgesia and terms used in related studies. The history and use of preemptive analgesia is reviewed, along with various treatment options like opioids, nonopioid analgesics, regional anesthetic techniques, peripheral nerve blocks, and cryoanalgesia. Risk factors for chronic postsurgical pain are listed. Postoperative pain management includes opioids, nonopioids like acetaminophen and NSAIDs, antidepressants, anticonvulsants, IV lidocaine, and alpha-2 agonists to improve analgesia and reduce side effects.

1. Saurabh Gupta
VHK-1435

2. Preemptive Analgesia
 PREEMPTIVE analgesia is an antinociceptive treatment
that prevents establishment of altered processing of
afferent input, which amplifies postoperative pain.
 Preemptive analgesia has been defined as treatment
that:
 (1) starts before surgery;
 (2) prevents the establishment of central sensitization
caused by incisional injury (covers only the period of
surgery); and
 (3) prevents the establishment of central sensitization
caused by incisional and inflammatory injuries.

3. Terms Commonly Used in Studies
on Preemptive Analgesia
 Central sensitization —persistent postinjury
changes in the central nervous system that result
in pain hypersensitivity
 Central hyperexcitability —exaggerated and
prolonged responsiveness of neurons to normal
afferent input after tissue damage
 Preincisional treatment —treatment that starts
before an initial surgical incision
 Postincisional treatment —treatment that starts
immediately after the end of operation.

4. History and progress in pre-emptive
analgesia
 Pre-emptive analgesia would block the induction
of central neural sensitization brought about
by the incision and reduce the intensity of acute
postoperative pain ( proposed first by Crile and
later by Wall)
 General anesthesia may attenuate the
transmission of afferent injury barrage from the
periphery to the spinal cord and brain, but it
doesn’t block the transmission

5. Treatment
 1-Systemic opiods
 Pure Agonists
Morphine, oxymorphone, meperidine,
hydromorphone, fentanyl
 Partial agonists, mixed agonist-antagonists
Buprenorphine
Butorphanol
 Pure Antagonists (reversal of agonists)
Naloxone

6. Conti…
 2-Nonopioid analgesics:
 ACETAMINOPHEN & NSAIDS like- Diclofenac, Ibuprofen
 3-Regional anesthetic techniques .
a : Intrathecal analgesia.
 b :Epidural analgesia: Provides superior pain
relief and attenuate the stress response to surgery,
particularly continuous infusion during and after
surgery.

7. Conti…
Combined use of epidural local anesthetics and
adjuvants provides introperative analgesia and
postoperative pain effectively
 4-Peripheral nerve blocks
 5-Cryoanalgesia: is a procedure used to
temporarily block nerve conduction along
peripheral nerve pathways. The
procedure, which involves insertion of a
small probe to freeze the target nerve

8. POST-OPERATIVE PAIN
 Acute Post-operative Pain
 Surgery
Tissue trauma or nerve injury
Inflammation due to release of inflammatory mediators
Hyperalgesia and Allodynia (increased response of neurons)

9. Chronic Post-surgical Pain
 Pain lasting form more than 1 month after surgery
 Risk factors for CPSP
1. Repeat surgery
2. Catastrophizing
3. Anxiety
4. Genetic predisposition
5. Radiation therapy to that area
6. Moderate to severe post-operative pain
7. Surgical approach with risk of nerve damage
8. Neurotoxic chemotherapy
9. Depression

10. POST-OPERATIVE MANAGEMENT
 OPOIDS – MORPHINE (PROTOTYPIC
AGENT)
 IV, IM ,ORAL AND TRANSDERMAL ROUTES
 MODERATE POTENCY,SLOW ONSET AND INTERMEDIATE
DURATION OF ACTION.
 OTHER OPOIDS COMMONLY USED –
1. HYDROMORPHONE
2. FENTANYL
3. MEPERIDINE
4. TRAMADOL

11. NON-OPOIDS ANALGESICS

DRUG:

Acetaminophen (paracetamol)-Effective analgesic
for acute pain

Nonselective NSAIDs (eg, ibuprofen, ketorolac,
naproxen)-Effective in treatment of acute
postoperative pain

COX inhibitors(Aspirin)-Effective in treatment of
acute postoperative pain

Ketamine: subanesthetic doses-Effective adjuvant
for pain associated with central sensitization (eg,
severe acute pain, neuropathic pain, opioid-
resistant pain)

12. Antidepressants and selective serotonin
reuptake inhibitors

Useful for acute neuropathic pain

Anticonvulsants (Gabapentin and pregabalin)-Reduce
postoperative pain, opioid requirements, and incidence of
vomiting, pruritus, and urinary retention, but increase risk of
sedation

May be useful for acute neuropathic pain (based on experience
with chronic neuropathic pain)

IV lidocaine infusion- Opioid sparing; reduced pain scores, nausea,
vomiting .

a2 Agonists (clonidine, dexmedetomidine)-Improves perioperative
opioid analgesia. Decreased opioid requirements and opioid side
effects

Side effects: sedation, hypotension