1. Mansour Choubsaz MD Kums.ac.ir

2. Barriers to Pediatric Pain Control Belief that children, especially infants, do not feel pain the way adults do Lack of routine pain assessment Lack of knowledge in pain treatment Fear of adverse effects of analgesics, especially respiratory depression and addiction Belief that preventing pain in children takes too much time and effort

3. Background Historically children and infants received less post- operative analgesia than adults children are often undertreated for pain Specifically in neonates: neonates can experience pain by 26 weeks of gestation Mature afferent pain transmission Untreated pain in neonates lead to increased distress and altered pain response in the future

4. 5 General Principles of Pain Management Anticipate & prevent pain Adequately assess pain Use multi-modal approach Involve parents Use non-noxious routes

5. Assessment in Neonates & Infants Challenging Combines physiologic and behavioral parameters Many scales available NIPS (Neonatal Infant Pain Scale) FLACC scale (Face, Legs, Activity, Cry Consolability)

8. ANATOMIC AND PHYSIOLOGIC DIFFERENCES Total body water represents about 80% of body weight in full-term newborns. This drops to 60% of body weight by 2 years of age,

10. The larger extracellular and total body water in infancy lead to a: greater volume of distribution for water-soluble drugs.

11. Cardiac output is relatively higher in infants and children than adults is preferentially distributed to vessel rich tissues such as the brain allowing for rapid equilibration of drug concentrations.

13. Immaturity of the blood–brain barrier in early infancy increased passage of more water-soluble medications such as morphine

14. This combination of increased blood flow to the brain and increased drug passage through the blood–brain barrier can lead to: higher central nervous system drug concentrations more side effects at a lower plasma concentration.

15. Both the quantity and binding ability of serum albumin and a-1 acid glycoprotein (AAG) are decreased in newborns relative to adults. This may result in higher levels of unbound drug, with greater drug effect and toxicity at lower overall serum levels. This has led to lower local anesthetic dosing recommendations in neonates and young infants,

16. although neonates have shown the ability to acutely increase AAG levels while on continuous local anesthetic infusions. The difference in serum protein quantity and binding ability disappears by approximately 6 months of age.

17. Neurotransmitters and peripheral and central pathways necessary for pain transmission are intact and functional by late gestation opiate receptors may function differently in the newborn than in adults Cardiorespiratory, hormonal, and metabolic responses to pain in adults have also been well documented to occur in neonates

19. The spinal cord and Dura mater in the newborn and infant extend to approximately the third lumbar (L3) and third sacral (S3) vertebral level reach the adult levels of approximately L1 and S1 to S2 by about 1 year of age. The lower-lying spinal cord in young infants is thus theoretically more vulnerable to injury during needle insertion at mid- to upper-lumbar levels..

22. ANATOMIC AND PHYSIOLOGIC DIFFERENCES The intercristal line connecting the posterior superior iliac crests, used as a surface landmark during needle insertion, crosses the spinal column at the S1 level in neonates versus the L4 or L5 level in adults.

24. There is less and more loosely connected fat in the epidural space in infants versus adults explaining in part the relative ease with which epidural catheters inserted at the base of the sacrum can be threaded to lumbar or thoracic levels in infants and small children.

25. pediatric patient may be unable or unwilling to verbalize or quantify pain a number of developmentally appropriate pain assessment scales have been designed for use in both infants and children. They are based on : self-report behavioral and/or physiologic measures

29. Children over approximately 8 to 10 years of age may be able to use the standard adult numeric rating or visual analog scale to self- report their pain. Specialized self-reporting scales can be used in patients as young as 3 years of age Behavioral or physiologic measures are available for younger ages and for developmentally disabled

30. Children between 3-8 years Usually have a word for pain Can articulate more detail about the presence and location of pain; less able to comment on quality or intensity Examples: –Color scales –Faces scales

32. NONOPIOID ANALGESICS Acetaminophen (paracetamol) is very commonly used in pediatric patients, alone or in combination with other analgesics. It is often administered rectally in the perioperative period in infants or children for whom oral intake is not an option. higher dosing, at least initially, is needed if given rectally Suppository insertion prior to surgical incision does not appear to significantly alter acetaminophen kinetics and may result in more timely analgesia in the early postoperative period.

33. Higher-dose rectal acetaminophen has been shown to be equianalgesic to intravenous ketorolac following tonsillectomy to have a significant opioid-sparing effect in children undergoing outpatient surgery. An intravenous form of acetaminophen is also available

34. Acetaminophen dosing in premature and term neonates is less well defined overall elimination in small studies is similar between neonates, children and adults. Dose-dependent hepatotoxicity is the most serious acute side effect of acetaminophen Acute hepatotoxicity appears to be less common and less likely to be fatal in children than adults.

35. NONSTEROIDAL ANTI-INFLAMMATORY DRUGS widely administered to children. reduced postoperative pain scores decreased supplemental analgesic requirements Intravenous ketorolac is used widely in children, with a generally good safety record.

36. The clinical significance of NSAID effects on bleeding remains controversial avoidance by some in procedures such as tonsillectomy. Bleeding, renal damage, and gastritis are more likely to occur with : prolonged administration in the presence of coexisting disease.

37. Acetaminophen and NSAIDs are often given in combination they work by different mechanisms their toxicity does not appear to be additive.

38. Aspirin is not used for postoperative pain management in infants and children highly significant association with Reye syndrome. Reye syndrome is an acute, fulminant, and potentially fatal hepatoencephalopathy occurs in children with influenza-like illness or varicella who ingest aspirin-containing medications.

39. OPIOID ANALGESIA Oral, parenteral, and epidural opioids are widely employed in infants and children Codeine is given orally in a dose of 0.5 to 1 mg/kg and often in combination with acetaminophen More potent oral opioids commonly administered to adults are also used

40. PATIENT-CONTROLLED ANALGESIA used in children as young as 5 to 6 years of age with morphine the most commonly used hydromorphone and fentanyl more commonly used alternatives Compared to PRN intramuscular opioids, PCA has been shown to be safe in children and provide more effective analgesia

41. A low-dose continuous or “background” infusion is sometimes added for patients following major surgery to optimize analgesia.

42. PARENT/NURSE-ASSISTED ANALGESIA The concept of PCA has been expanded to allow parent- or nurse-assisted analgesia in select cases in which the patient is unwilling or unable, because of age, developmental delay, or physical disability, to operate the PCA button. used with caution as it does away with one of the safety features of PCA, in that the patient is theoretically less likely to self-overdose.

43. More recently the concept of parent- or nurse- assisted epidural analgesia has been introduced to optimize dosing flexibility and pain relief given via the epidural route

44. Compared to adults given morphine, neonates and premature infants have a : longer elimination half-life lower plasma clearance marked interindividual variability in plasma morphine concentration. achieve a higher plasma concentration for a longer duration

45. By approximately 6 to 12 months of age, the kinetics of morphine and fentanyl approach adult values children soon thereafter demonstrate increased plasma clearance and a shorter elimination half- life

46. “SINGLE-SHOT” CAUDALS One of the most widely used pediatric regional techniques palpable landmarks ease of caudal block insertion in infants and children versus adults. SSC is used in infants and children up to approximately 10 to 12 years of age having surgery from lumbosacral to midthoracic

47. “SINGLE-SHOT” CAUDALS Bupivacaine in concentrations of 0.125% to 0.25% is the most commonly used volumes of 0.5 to 1.5 ml/kg will provide upper- lumbar to low-thoracic levels, respectively An upper volume limit of 20 ml is generally used.

50. The maximum recommended bupivacaine dose is 2.5 to 3.0 mg/kg, with an upper limit of 1.25 mg/kg recommended in early infancy It is unclear whether block placement at the beginning versus the end of the procedure prolongs postoperative analgesia.

51. test dose 0.1 ml/kg (maximum 3 ml) of local anesthetic with 1:200,000 epinephrine (5 mg/kg) is used to ensure correct needle or catheter position. A 25% increase in T-wave amplitude 10-beat/min increase in heart rate 10% increase in systolic blood pressure within 60 s of administration considered a positive test dose

52. It is unclear whether block placement at the beginning versus the end of the procedure prolongs postoperative analgesia

53. procedure prolongs postoperative analgesia. Although usually used alone, bupivacaine can be combined epidurally with fentanyl, morphine, the a-2-adrenergic agonist clonidine, or other additives to prolong the duration and/ or density of analgesia.

54. Delayed respiratory depression up to 22 hr can occur with epidural morphine. Greater risk is seen in children less than 1 year of age and when parenteral opioids have also been given.

55. CONTINUOUS EPIDURAL INFUSIONS Epidural local anesthetic infusions with or without opioids or a-2-agonists have been used in infants and children for postoperative analgesia. Lower infusion rates are generally recommended in neonates and infants less than 3 to 6 months old As a rule, optimal analgesia is obtained with the catheter tip positioned at or near the dermatomes to be blocked.

56. CONTINUOUS EPIDURAL INFUSIONS It is possible in infants and smaller children to thread caudally inserted catheters to lumbar or thoracic levels. Catheter insertion may take place following induction of general anesthesia in infants and children Patient-controlled epidural analgesia has been successively used in children as young as 5 years of age.

57. Peripheral and truncal nerve blocks play an increasing role in pediatric postoperative pain relief These are typically performed under general anesthesia and increasingly with the use of ultrasound guidance. Ilioinguinal / iliohypogastric, rectus sheath, transverse abdominus plane, head and neck, and upper and lower extremity blocks are being done more frequently to provide analgesia in suitable candidates