Week 10 - Pediatric Chronic and Acute Pain Flashcards
What are the three types of pain?
- Nociceptive: somatic (well localized in soft tissue, bone, muscle, skin) and visceral (vague, visceral organs)
- Neuropathic: burning, shooting, tingling – damaged sensory nerves
- Functional Pain: chronic pain that impacts everyday functioning
What are the four stages of pain processing?
Transduction
Transmission
Modulation
Perception
What is the Transduction stage of pain processing?
Painful stimulus activates nociceptors
- mechanoreceptors (ruffini, meissner, pacinian, merkel)
- thermoreceptors (krause endings)
- free nerve endings
Damaged tissues release bradykinin, serotonin, histamine, substance P, prostaglandins – generates an electrical impulse along an axon
*going from mechanical stimulus to electrical impulse
What is the Transmission stage of pain processing?
- Electrical stimulus is propagated along axons from the PNS to the CNS
- Stimulus transmitted by A-delta (glutamate) and C-fibers (substance P)
- Nociceptors/Free nerve endings –> Peripheral Nerves –> Dorsal Horn (1st order)
- Spinothalamic Tract –> Thalamus –> Cerebral Cortex (2nd order)
What is the Modulation stage of pain processing?
- Alters incoming noxious stimuli
- Involves humoral and neural events (endogenous opioid systems, NMDA receptors, serotonin and norepi)
- Occurs between the thalamus and the brainstem interneurons of the dorsal horn, and descending inhibitory pathways (serotonin and norepinephrine)
- occurs between the 1st order and 2nd order neurons
- Descending inhibition
What is the Perception stage of pain?
- Patient “feels” pain
- Mediated by the cerebral cortex
- Most variable component of pain pathway – heavily influenced by behavioral, cognitive, affective, sensory, and emotional factors
What is the gold standard to acute pain management in pediatric patients?
A multimodal approach
- maximal analgesic benefit
- minimal adverse effects
*utilize medications with different mechanisms of action
Explain the pain pathway development for pediatric population
- Nociceptive pathways in the PNS and CNS develop in the 2nd and 3rd trimesters
- By 26 weeks the fetus responds to tissue injury and inflammation through withdrawal reflexes, ANS arousal, and hormonal stress responses
- Preterm infants are MORE sensitive to painful stimuli (reduced threshold for withdrawal to noxious stimuli, immature descending inhibitory pathways)
- Opioid receptors are present at birth, but inflammatory mechanisms are immature (may imply NSAIDs are ineffective in neonates)
What are the long term consequences of untreated neonatal pain?
Depression, anxiety, hyperalgesia, allodynia
-BUT… neonates who undergo painful procedures are commonly those who have chronic medical conditions — very difficult to correct for variables in the literature
What are the barriers to pediatric pain management?
- Historically pain undertreated – slow development of reliable and valid assessment tools, myth that infants don’t feel pain
- Fear of opioid side effects and addiction
- Lack of evidence-based pain management protocols
- Inadequate staff education regarding pain assessment and management
How do you assess pain in the pediatric population?
- Requires age appropriate assessment tool – must consider cognitive and developmental level
- Assessment of postop pain is greatly facilitated by preop introduction of assessment tool
- For children to understand magnitude and ordinal positions, they must be 7 years old (ie. 0-10 scale)
What is the FLACC behavioral pain scale? What age is it appropriate for?
Observational behavioral measure
Ages 2 months to 7 years old
Five behaviors have been shown to be reliable, specific, and sensitive when prediction analgesic requirements: facial expressions, vocalization or cry, leg posture, body posture, and motor restlessness
Indicated for use in medical procedures and postop pain
What is the comfort pain scale? What age is it appropriate for?
Developed for use in an ICU setting
0-18 years old
Assesses alertness, calmness/agitation, respiratory response, physical movement, blood pressure, muscle tone, facial tension, and heart rate
What are the Faces Pain Scales? What age are they appropriate for?
Wong Baker and Bieri Faces Pain Scales
Reliable and valid for children 3-18 years old
*do not require the concept of magnitude or serration and can be used by preschool aged children
What is the numerical rating pain scale? What age is it appropriate for?
- Self report metrics in which a pt is asked to quantify the severity of pain between 0-10
- Most accurately reflect ACUTE pain
Good reliability and validity for pts 7-17
How do you assess pain in cognitively impaired children?
Revised FLACC for pain assessment in the cognitively impaired
- children who are cognitively impaired experience pain more frequently because of many inherent conditions
- difficulty with pain assessment in this population has led to exclusion from research studies/clinical drug trials adding to the deficits in our knowledge
What “number” demands pain intervention?
Must consider pain score, behavioral signs, nature of the procedure, parental input, and overall clinical context to direct treatment decisions
What is the definition of acute pain?
Nociceptive pain resulting from tissue injury, inflammation, or infection
- most prominent immediately following injury –> gradual improvement over time with tissue repair
- responds to opioids, non-opioids, neuraxial anesthesia, peripheral nerve blocks, and non-pharmacologic measures
- rarely progresses to chronic pain
**Plan for addressing acute postop pain during preop period
Where can pain be treated?
Peripheral Level: local anesthetics, peripheral nerve blocks, NSAIDs, antihistamines or opioids
Spinal Cord Level: local anesthetics, neuraxial opioids, a2 agonists, NMDA receptor antagonists
Cortical Level: opioids, a2 agonists, voltage gated calcium channel agonists
What pain therapies are ideal for preterm infants with impaired central respiratory drive?
Acetaminophen
NSAIDs
Local Anesthetics
When are non-opioid analgesics used in the pediatric population?
- Sole agents for mild pain and as
- Adjuncts for moderate to severe pain
- limited by a ceiling effect
- ideally delivered on a scheduled basis for at least the first few days postop (supplemented with opioids PRN)
What is the max dose of acetaminophen for children, neonates, and preterm neonates?
Children: 75 mg/kg max
Neonates (32-44 weeks): 60 mg/kg max
Preterm (28-32 weeks): 40 mg/kg
- 3000mg overall max
- important to confirm w/ parents in tylenol containing products have been given preop
What is the recommended dose schedule for oral administration of acetaminophen in pediatrics?
10 mg/kg every 4 hours or 15 mg/kg every 6 hours for a total of 60 mg/kg
What are pediatric specific considerations for NSAIDs?
- NSAIDs do not cause increased risk of bleeding
- Combination therapy with acetaminophen and NSAIDs have a synergistic effect (should be admin at the same time, not alternating)
- May impair bone healing in pediatric spinal fusion pts
*avoid NSAIDs in kids w/ severe asthma or hyperreactive airways
What is the dosing for Precedex in pediatrics?
0.5 mcg/kg IV for maximal benefit
What is the most commonly used opioid in pediatrics?
Morphine
- dosing is very important due to M6 glucuronide formation (kidney function ok?)
- < 6 months are at greater risk for opioid-induced respiratory depression
What opioid is a better choice for children with hemodynamic instability?
Fentanyl
- avoid histamine release as with morphine
- commonly admin in 5mcg boluses (1mcg/kg total admin)
What age is appropriate for use of a PCA?
Most cognitively intact children age 7+
-gives sense of control back to the child
What are the benefits of regional anesthesia in the pediatric population?
Excellent pain control in children who may not tolerate large doses of opioids
Opioid sparing
Preemptive analgesia prevents “wind up” phenomenon
What are contraindications of regional anesthesia in the pediatric population?
- Anatomic anomalies
- Sepsis
- Coagulopathy
- Thrombocytopenia
- Surgical assessment postop
What are regional anesthesia considerations in the pediatric population?
- Will not see sympathectomy with neuraxial anesthesia as in adults
- Regional anesthesia is performed AFTER pt is alseep
- <6 months requires VERY careful attention to dosing (decreased protein binding –> increased risk of toxicity)
What are local anesthetic considerations for the pediatric population?
Neonates and young infants have decreased plasma proteins (a1aG) –> increased free fraction of LA
What is the max dose of lidocaine?
5 mg/kg plain
7 mg/kg with epi
What is the max dose of Bupivacaine?
2.5 mg/kg plain
3 mg/kg with epi
What is the max dose of ropivacaine?
2.5 mg/kg plain
What are the neuraxial anesthesia techniques used in the pediatric population?
Caudal: most common – analgesia of lower extremities and lower abdomen
Epidural: catheter left in <3 days to minimize infection risk – standard of care for pain management of open abdominal surgery
Spinal: provides surgical anesthesia, no other sedation needed, commonly used for urology procedures and other procedures of the lower extremity
When can a pediatric patient go home after neuraxial anesthesia?
Whenever they show spontaneous movement of the lower extremities
-need to show evidence of the block wearing off prior to discharge
What are non-pharmacologic pain interventions for the pediatric population?
Cognitive: distraction, imagery hypnosis
Behavioral: relaxation, play therapy, biofeedback
Physical: massage, heat/cold, acupuncture
What is the definition of chronic pain?
Pain that persists beyond the expected time of tissue healing – 3-6 months
- may begin as acute pain and transition to chronic
- may continue due to re-injury or the persistence of noxious stimuli
- may exist in the absence of identifiable pathology
*multidisciplinary approach to chronic pain management is essential
What are the risk factors for pediatric chronic pain development?
- Underlying depression and anxiety
- History of abuse
- Female
- Family dynamics
- Certain medical conditions (Sickle cell anemia, Cystic fibrosis, Epidermolysis bullosa, Cancer)
- Pain as the primary pathology (Abdominal pain, Headaches, Back pain)
How do you treat acute on chronic pain in the pediatric population?
Patients with chronic pain presenting to the OR
- identify their current treatment plan and continue throughout the perioperative period – add medications on top of current treatment to treat the acute pain
- consult institutional pain service for recommendations
