Pediatric pain Management By: Dr. Gamal Adel Under supervision Prof Dr. Hany Elzahaby
Definition of pain • Pain as an unpleasant sensation that originates in traumatized tissue and warns of injury • An unpleasant sensory and emotional experience normally associated with tissue damage or described in terms of such damage
Classification • Nociceptive pain • is pain in which normal nerves transmit information to the central nervous system about trauma to tissues • Neuropathic pain • is pain in which there are structural and/or functional nervous system adaptations secondary to injury
Other classification.. • Cutaneous pain • Somatic pain • Neuropathic pain • Phantom limb pain • Visceral pain
Pain transmission • Impulses in C fibers or A delta fibers travels to the spinal cord (Peripheral Nerve Sensitivity) • To the dorsal horn (central sensitization ) • Competition by encephalin-producing descending fibers from the brain stem interact with both pre-synaptic and post-synaptic cells to inhibit transmission “pain gate” • Incoming signals in the A beta fibers of a peripheral nerve can alter sensitivity of the post-synaptic cells to painful stimuli arriving in C and A delta fibers
Pain modulating loops • Supraspinal pain modulating loops exist that can increase or decrease the amount of pain • Reticular formation, cortico-reticular signals • The dorsolateral pontinetegmentum • The rostral ventral medulla • The dorsal medulla • The caudal medulla • The lateral hypothalamus
Pain modulating loops (cont...) • Descending Pain Modulating Pathways • Periaqueductal grey matter raphenuclus • locus ceruleus to dorsal horn • Spinocerebral Ascending Pathways • The spinothalamic pathway • The spinoreticular pathway • Areas of the brain • Sensory and motor cortex areas • Premotor cortex ( for planning of movement) • Other parts of the parietal cortex and frontal cortex • Cingulate cortex • Insula • Occipital cortex
Causes of undertreated pain in children Wrong beliefs
Causes of undertreated pain in children • Children tolerate pain better than adults • Children become accustomed to pain or painful procedures under pain recognition • Children’s behavior reflects their pain intensity.
Other facts… • Pain is less harmful than the side effects of analgesic therapy • Health care providers frequently have limited knowledge regarding state of the art pain management • Limited verbal communication in the younger children population
Tools.. • Appropriate age related tool is used to asses and document level of pain. • < 3 years old .... Behavioral observation or FACES tool or FLACC scale • 3-7 years old .... FACES or visual analog scale • 8-14 years old .. Visual analog scale and numeric scale or oucher scale or pocker chip scale
FLACC SCORE • Children < 3 years and Children with Developmental disabilities
Non-pharmacologic Strategies • Non-pharmacologic strategies play an important role in pain management and can be combined with analgesics to minimize the pain experience • Non-pharmacologic approaches for the treatment of pain in children include psychological strategies, education and parental support
Classification of methods • According to type: 1-Rehabilitative: heat, cold, ultrasound, holding, mobilization or immobilization 2-Psychological: Education, relaxation, imagery, psychotherapy, counseling, music, swaddling and rocking 3-Complementary and Alternative: Acupuncture ,TENS and massage
Mechanism of action of complementary methods : • Activation and stimulation of large-diameter non-noxious fibers and inhibit transmission of nociceptive information from the periphery to the brain.
Topical anesthetics • Topical local anaesthesia of the skin should be routine before all needle procedures in children • The eutectic mixture of local anesthetics (EMLA cream) is very effective when applied for 60–90 min, while tetracaine gel has a slightly more rapid onset of action (40 min) and produces vasodilatation.
Cooling Spray (Fluori-Methane) • Vapocoolant spray. • It was found that all pain measures and cry duration were similar for EMLA and the Vapocoolant. The Vapocoolant spray is much less expensive than EMLA cream and significantly faster acting
Systemic analgesics • Opioid Analgesics Opioids produce analgesia by acting on both central and peripheral mu, kappa and delta Opioid receptors to inhibit the transmission and perception of nociceptive input.
Morphine clearance in term infants greater than 1 month old is comparable with children from 1 to 17 yr old. • In neonates aged 1–7 days, the clearance of morphine is one-third that of older infants and elimination half-life approximately 1.7 times longer. • Morphine sulphation is efficient and effective in the early neonatal period while glucuronidation maturity is some weeks later.
Titrated loading dose of i.v. morphine 50 µg kg-1 increments, repeated up to ·4 times while I.V. or s.c. morphine infusion10–40 µg kg-1 h- • PCA with morphine • Bolus dose 20 µg kg-1 • Lockout interval 5 min • Background infusion 4 µg kg- h-1 • (especially first 24 h) • Nurse controlled analgesia (NCA) with morphine • Bolus dose 20 µg kg-1 • Lockout interval 30 min • Background infusion 20 µg kg-1 h-1
Routes of administration • Subcutaneous cannula • subcutaneous cannula can be sited while the child is anaesthetized or under topical local anaesthetic cream and nurse-administered bolus doses can be highly effective. • A 24-gauge cannula can be inserted easily into the subcutaneous tissue of the anterior abdominal wall or the deltoid area of the upper outer arm • The pharmacokinetics and dynamics are similar to the i.v. route provided peripheral tissue perfusion is stable and adequate
Other opioids • Fentanyl, sufentanil, alfentanil, and remifentanil may have a role after major surgery and in intensive care practice. • Opioids with low context-sensitive half time are of extremely rapid recovery because of esterase clearance are best delivered by target controlled infusion devices.
Patient-controlled analgesia (PCA) • (PCA) is now widely used in children as young as 5 yr. • improve sleep pattern without increasing the adverse effects. • Children have control over their own analgesia, which has considerable psychological benefits.
Contraindications to patient-controlled analgesia • Child less than 5 yr of age • Child with learning difficulties • Child physically unable to operate demand button • Increased intracranial pressure • Depressed conscious level • Airway obstruction
Assessment and management of adverse effects • Respiratory depression and sedation • depressing central respiratory drive and also causing a partially obstructed upper airway as a result of oversedation • If a child is noted to be oversedated. have a consistent pulse oximetry reading of less than 94% • ventilatory frequency less than 20 bpm in an infant or less than 12 bpm in an older child.
Management of opioid-induced respiratory depression • Support the airway and give high flow oxygen • Assist breathing if hypoventilation severe • Discontinue opioid administration • Give i.v. naloxone 2–4 µgkg–1 • Repeat naloxone 2–4 µgkg–1 up to 10 µgkg–1
Nausea and vomiting • Cause:opioidstimulation of the chemoreceptor trigger zone in the medulla of the brain • Management • reduce the dose of drug given.Antiemetics: but may cause extrapyramidal signs in children if given frequently(e.g. metoclopramide and prochlorperazine). The 5-HT3 antagonist ondansetron does not produce sedation or extrapyramidal problems. • Transdermalhyoscine has also been used as there is often a component of motion sickness to opioid-induced nausea. Low-dose droperidol is another alternative. • changing to a different opioid decreases the incidence of nausea and vomiting
Itching • The cause of pruritus induced by opioids is unclear • common when spinal opioids are used common when spinal opioids are used • Antihistamine drugs (Chlorpheniramine) but they increase the level of sedation • It may be safer to use a small dose of naloxone which does not affect the analgesic properties of the opioid • Ondansetron 0.1 mg kg–1 may be effective in reducing pruritus caused by epidural or spinal opioids
Urinary retention and gastrointestinal symptoms • In small babies, gentle suprapubic pressure allows bladder emptying but it may be necessary to catheterize older patient • low dose of naloxone0.5–2 µg kg–1 • Laxatives, suppositories and micro-enemas may be required.
Muscle spasms • chest wall rigidity particularly with fentanyl • adductor muscle spasms may be caused by accumulation of stimulatory metabolites such as morphine-3-glucuronide specially if used in orthopedic surgeries for long periods.
Non-steroidal anti-inflammatory drugs (NSAIDs) • Pharmacokinetic studies of NSAIDs have revealed a higher than expected dose from adult doses • NSAIDs should be avoided in: • infants less than 6 months of age. • Children with aspirin or NSAID allergy • dehydration or hypovolaemia • renal or hepatic failure • coagulation defects • significant risk of haemorrhage
Adverse effects The most commonly reported adverse effects are
Adverse effects • Bleeding, gastrointestinal, skin • Hepatic, and renal toxic effects. • Edema,bone marrow suppression,Stevens– Johnson syndrome
COX-2 inhibitors The COX-2 inhibitors available at present meloxicam, nimesulide, celecoxib, • etoricoxib,lumaricoxib,valdecoxib • Parecoxib(rofecoxib having been withdrawn recently) • By sparing physiological tissue prostaglandin production while inhibiting inflammatory prostaglandin release, COX-2 inhibitors offered the potential of effective analgesia with fewer side effects than the NSAID
Acetaminophen (paracetamol) • Acetaminophen inhibits prostaglandin synthesis in the hypothalamus probably via inhibition of cycloxygenase-3 • This central action produces both antipyretic and analgesic effects. • Acetaminophen also reduces hyperalgesia mediated by substance P • reduces nitric oxide generation involved in spinal hyperalgesia induced by substance P or NMDA.
Dosage: • Oral and rectal dosage 15-20 mg kg-1 and maintenance 15 mg kg-1 every 8-12hours according to age • Total daily doses of paracetamol should not exceeed approximately 90 mg kg–1 day–1 for up to 72 h • Peak analgesia even after i.v. administration is between 1 and 2 h.
Dosage: • The novel i.v. formulation pro-paracetamol is cleaved by plasma esterases to produce half the mass of acetaminophen. Recently, mannitolsolubilizedparacetamol (PerfalganTM) has become available for i.v. use. • therapeutic plasma concentration’ of 10–20 mg ml-1 • I.V. acetaminophen (PerfalganTM) (15 mg kg-1) as slow i.v. infusion over 15 min children older than 1 year.
Pediatric regional anesthesia • Suggested benefits include decreased intraoperative requirement for general anesthetics in acute pain management • less of a need for parenteralopioids limiting the incidence of side effects limitation of stress hormone responses Improved postoperative analgesia shortened recovery for outpatient surgery
Differences of pediatrics • In younger children, particularly infants, nerves have a thinner myelin sheath, a smaller fiber diameter, and a shorter internodal distance. • lack of hypotensive response from a sympathectomy produced by the local anesthetic increased risk of toxicity • Neonates and infants have a lower AAG concentration in serum as compared with adults; therefore, their free fraction of local anesthetics is increased accordingly
The intrinsic clearance of bupivacaine is only one-third of that in adults at 1 month of age, and two-thirds at 6 months • Infantsalso have decreased levels of plasma pseudocholinesterase thattheoretically could increase the risk of toxicity with esterlocal anesthetics
Upper Extremity Nerve Blocks • Most famous axillary and parascaleneblocks • Dose:- • 0.3–0.5ml/kg bupivacaine 0.25% or ropivacaine 0.2% in children youngerthan five–eight years. • In older children, the larger concentrationsmay be required, i.e., 0.3–0.5 mL/kg bupivacaine 0.5%or ropivacaine 0.5%.
The axillary nerve block Technique: • The needle is inserted immediately superior to the artery high in the axilla. The needle should be at a 45 degree angle pointing cephalad toward the midpoint of the clavicle and advanced until there is evidence of nerve stimulation seen distally