Pain Physiology

1
Pain Physiology

• Pain is a complex physiologic process
• Transduction
• Transmission
• Perception of pain
• Modulation

2
Types of Pain

• Nociceptive Pain
• (normal processing of pain)
• Somatic
• Bone, joints, connective tissue
• Achy, throbbing
• Well localized
• Visceral
• Organs, soft tissue
• Aching, cramping
• Localized, diffuse

• Neuropathic Pain
• (abnormal processing of pain)
• Centrally mediated
• Deafferentation pain
• Sympathetic pain
• Peripherally mediated
• Polyneuropathies
• Mononeuropathies
• Sharp, shooting, electric
• Usually requires adjuvant medications

3
Tolerance

• ? effect of a medication over time, requiring ?
  dose to achieve same level of efficacy
• Should consider differential diagnosis
• Tolerance ? addiction
• Easily managed by ? dose or ? interval between
  dosing
• Should not withhold opioid

4
Physiological Dependence

• Development of withdrawal syndrome after
• Abrupt discontinuation of therapy
• Substantial dose reduction
• Administration of antagonist medication
  (naloxone)

5
Psychological Dependence (Addiction)

• Pattern of compulsive drug use characterized by
  continued craving for an opioid and the need to
  use the opioid for effects other than pain relief
  
• Three distinguishing characteristics
• Continued cravings with/without pain
• Illegal and anti-social behavior in order to
  obtain the drug
• Chronic, relapsing condition

APS, 2008
6
Pain Management

• Severe pain should be seen as a medical emergency
• Rapid assessment and treatment of pain is
  imperative
• Close collaboration with physicians/APNs,
  pharmacists, other nurses, and family is
  essential to optimum use of analgesic treatments.

7
WHO Analgesic Stepladder
8
By the Clock

• Acetaminophen/NSAIDs PRN or ATC
• Opioid medications should be given on scheduled
  basis
• Provide adequate PRN doses for breakthrough pain
• Adjuvant medications dependent on particular
  agent

9
Stay Ahead of Pain

• Individualize to the child based on their level
  of pain, prior experience with opioids, and
  desired activity level
• Frequently assess pain level and adjust as
  necessary
• In pain crisis - rapid titration to comfort is
  imperative
• Dosages calculated by weight

10
Least Traumatic Route of Administration

• Oral is not always the least traumatic means,
  particularly in toddler/early childhood
• Avoid rectal
• No SHOTS

11
Routes

• Oral/Transmucosal
• Long-acting preps
• Breakthrough IR preps
• Transdermal
• Limited use in escalating pain

12
Routes (cont.)

• Topical
• Intravenous/Subcutaneous
• Intraspinal/epidural

13
Opioids in Neonatal Population

• Reduce clearance of majority of opioids
• Prolonged half-life
• Tachyphylaxis