Pain Management

Introduction

Pain management can be a complex topic in anesthesia. Patient factors, like age, comorbidities, and pre-existing chronic pain can help guide analgesia during the operative period. Surgical factors, like the expected intra-operative and post-operative pain can also help determine which agents to use and in what dosage.

Definitions

  1. Multimodal Analgesia - use of different classes of drugs to optimize analgesia while minimizing individual drug side-effects

WHO Pain Ladder

The classic WHO pain ladder can be a useful reference when considering pain management in any patient.

graph TB
A[Foundational Analgesics];
B[Tramadol & Low Dose Opioids];
C[Hydromorphone, Morphine, Oxycodone];
D[Fentanyl Patch, Extended Release Opioids]
A-->B
B-->C
C-->D

Analgesia Overview

Maximize Non-opioid Analgesia

Consider pre-operative AcetaminophenAcetaminophen
Mechanism of Action 1

Central analgesic effect descending serotonergic pathways.
Likely component of COX inhibition (similar to NSAIDs)


Indications

Analgesia (see Pain Management)


D... Consider the use of NSAID Private or Broken Links
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s, but this will depend on the type of surgery. Generally, NSAIDs are given at the end of an operation if hemostasis is adequate and concerns of bleeding are low.

  • Ibuprofen
  • KetorolacKetorolac
    What is Ketorolac?

    Nonsteroidal anti-inflammatory drug used primarily for short term, acute pain management.


    Mechanism of Action 1

    COX-1 and COX-2 inhibitor

    COX-1: involved in pl...

    Opioids

    Opioids are the workhorse of analgesia in the perioperative period. Each of the opioids has a different onset of action and duration of action. The degree of analgesia (determined by the choice and dose of opioid) should be matched to the expected stimulus of the operations.

For instance, RemifentanilRemifentanil
What is Remifentanil? 1

Ultra-short-acting synthetic opioid analgesic.
Used for pain management and as an adjunct to anesthesia.
Rapid onset and short duration of action.


Mechanism of Acti... is a good choice in operations that have brief, potent stimulation but minimal post-operative pain.

HydromorphoneHydromorphone
What is Hydromorphone? 1

Semi-synthetic opioid analgesic derived from morphine.
Used for the management of moderate to severe pain.


Mechanism of Action & Pharmacokinetics 12

Primarily... and MorphineMorphine
What is Morphine? 1

Naturally occurring opioid analgesic derived from the opium poppy.
Used for the management of moderate to severe pain.


Mechanism of Action & Pharmacokinetics 12

Pr... are good choices when there is intra-operative and post-operative pain.

TramadolTramadol
What is Tramadol? 1

Synthetic opioid with analgesic properties indicated for treatment of moderate-severe pain.
Can be administered orally as immediate release or extended release tablets or a... can be used after surgery and is commonly prescribed because it does not require a triplicate.

Multimodal Analgesia

There are a variety of co-analgesic options that can be infused or bolused throughout the operation. A few options include:

  1. KetamineKetamine
    What is Ketamine?

    Rapidly acting NMDA receptor antagonist that can be used for Induction of General Anesthesia, sedation, and Pain Management


    Mechanism of Action & Pharmacokinetics...
  2. Lidocaine
  3. Dexmedetomidine
  4. Magnesium

Regional Anesthesia

Depending on the operation, there are a variety of single shot and catheter based regional techniques that can provide intra-operative and post-operative pain control. A few options include:

  1. Spinal anesthesia – used commonly in c-secitons
  2. Epidural anesthesia – used in labouring patients and laparotomies
  3. Adductor canal nerve blocks – used in some knee and lower extremity surgeries
  4. Interscalene nerve block – can be useful for surgery surgery