===== Perioperative Analgesia =====

Perioperative analgesia refers to pain management strategies implemented **before, during, and after surgery** to reduce pain, improve recovery, and minimize complications. It is a critical component of **multimodal perioperative care**, especially in enhanced recovery after surgery (ERAS) protocols.

==== Goals ====
  * Prevent and control postoperative pain
  * Reduce stress response to surgery
  * Facilitate early mobilization and rehabilitation
  * Minimize opioid use and related side effects
  * Improve overall surgical outcomes

==== Phases of Perioperative Analgesia ====

=== Preoperative Phase ===
  * Patient education and expectation setting
  * **Pre-emptive analgesia**: analgesics *before incision* (e.g. paracetamol, NSAIDs, gabapentinoids)
  * Optimization of comorbidities (e.g. renal function, anticoagulation)

=== Intraoperative Phase ===
  * **Regional anesthesia**: spinal, epidural, nerve blocks (e.g. scalp block, TAP block)
  * **Systemic analgesics**: opioids, NSAIDs, paracetamol, ketamine, lidocaine infusion
  * **Adjuvants**: clonidine, dexmedetomidine, magnesium sulfate

=== Postoperative Phase ===
  * **Multimodal analgesia**: combining different drug classes (e.g. paracetamol + NSAID + low-dose opioid)
  * **Patient-controlled analgesia (PCA)**
  * Continuation of **regional techniques**: epidural infusion, nerve catheter
  * **Non-pharmacological methods**: cold therapy, physical therapy

==== Multimodal Analgesia ====
This is the cornerstone of effective perioperative pain management:

  * **Opioid-sparing techniques**
  * Use of **regional blocks** and **non-opioid drugs**
  * Reduces opioid-related side effects: nausea, sedation, ileus

==== Considerations ====
  * Type and extent of surgery (minor vs. major)
  * Patient factors: age, renal/hepatic function, opioid tolerance
  * Risk of chronic post-surgical pain
  * Avoiding drug interactions and adverse effects

==== Example: Neurosurgery (Scalp Blocks) ====
In craniotomies, **scalp nerve blocks** using **bupivacaine ± clonidine** can:

  * Reduce intraoperative hemodynamic fluctuations
  * Provide postoperative analgesia
  * Reduce opioid requirements