Management of Acute Pain in Children: Pharmacologic

Patient Controlled Analgesia

Patient controlled analgesia (PCA) is widely used for postoperative pain relief in both children and adults. With appropriate preoperative teaching and encouragement, children as young as 6 to 7 years of age can independently use the PCA pump to provide good postoperative pain relief.⁴¹ Children between the ages of 4 and 6, however, generally require encouragement from their parents and nursing staff to push the button before anticipated painful movements or procedures. Even with encouragement, the failure rate among 4 and 5 year olds with PCA appears quite high. For younger children, NCA has recently gained popularity to permit small titrated dosing of opioids for infants and children unable to use the PCA button.⁴²

Typical Starting Parameters for PCA
Drug	Bolus dose (mcg/kg)	Continuous rate (mcg/kg/hour)	4 hour limit (mcg/kg)
Morphine	20	4-15	300
Hydromorphone	5	1-3	60
Fentanyl	0.25	0.15	4
Lockout interval = 5 to 7 minutes. The lockout interval is the period during which the PCA unit is refractory to further demands by the patient, and is necessary to prevent patients from taking an additional dose before appreciating the effect of the preceding dose.

PCA may be administered either alone or in conjunction with a low-dose continuous infusion. Initial parameters for the most commonly used agents can be found in the table, Typical Starting Parameters for PCA. Morphine, hydromorphone and fentanyl have all been used and there are insufficient data to recommend one of these agents as uniquely preferable to the others. Morphine has been the most extensively studied in children, however, and remains the most popular first-line analgesic. Meperidine is generally not recommended when other opioids are available because of the potential for seizures due to its metabolite, normeperidine.

Basal infusions improve sleep quality, but have been associated with episodes of hypoxemia when used for postoperative pain management in children.^43,44 One solution for this has been to combine PCA in bolus-only mode with round-the-clock administration of NSAIDs and/or acetaminophen. For children with acute pain associated with chronic illness, most of whom have developed some tolerance to opioid analgesics, a larger basal infusion is preferred to adequately control disease-related pain. For tumor-related pain or palliative care, roughly two-thirds of the overall requirement is provided from the basal infusion.