CPHON Pain Assessment and Management in Pediatric Oncology 2 — Questions and Answers
Question 1: A parent of a child with terminal cancer asks why morphine is being increased so frequently, saying: 'I'm afraid giving more pain medicine will make him die faster.' The nurse's most appropriate response addresses which ethical principle?
- The principle of double effect: the intent is to relieve suffering, not hasten death, and adequate pain control is both an ethical obligation and does not shorten life when used appropriately (Correct answer)
- Autonomy: the parent has the right to refuse pain medication on the child's behalf
- Justice: all patients deserve equal pain management regardless of diagnosis
- Beneficence alone justifies administering any dose without parental explanation
Correct answer: The principle of double effect: the intent is to relieve suffering, not hasten death, and adequate pain control is both an ethical obligation and does not shorten life when used appropriately
The principle of double effect addresses the ethical concern that a medication given to relieve suffering may have a foreseeable side effect of potentially hastening death. Evidence shows appropriate opioid titration for pain does not shorten life.
The principle of double effect is an important ethical framework in palliative care: an action (increasing morphine) is ethically permissible if (1) the act itself is not intrinsically wrong; (2) the agent intends only the good effect (pain relief), not the bad effect (hastened death); (3) the bad effect is not the means to the good effect; and (4) there is proportionately serious reason for the action (severe uncontrolled pain). Importantly, extensive evidence shows that well-titrated opioid therapy does NOT hasten death — in fact, it may prolong life by reducing the harmful physiologic effects of uncontrolled pain (stress response, hypoxia from splinting). The nurse should validate the parent's concern, explain the double effect principle in accessible language, and emphasize that the goal is to maximize the child's comfort and quality of remaining time.
Question 2: A 15-year-old with osteosarcoma and bone metastases asks the nurse why she needs to take her oral morphine around the clock rather than just when in pain. The most accurate response is:
- Cancer pain is often constant; scheduled dosing maintains a steady analgesic blood level to prevent pain from breaking through, while PRN dosing allows painful drug troughs (Correct answer)
- Around-the-clock dosing is required by law for cancer patients
- Scheduled dosing allows you to use less medication overall by preventing addiction
- PRN dosing is actually better for cancer pain but is too difficult for nurses to manage
Correct answer: Cancer pain is often constant; scheduled dosing maintains a steady analgesic blood level to prevent pain from breaking through, while PRN dosing allows painful drug troughs
Chronic cancer pain is best managed with scheduled (around-the-clock) dosing to maintain consistent analgesic blood levels and prevent the pain-analgesic cycle of severe pain before dose and side effects after each PRN dose.
The cornerstone of chronic cancer pain management is around-the-clock (ATC) scheduled dosing of long-acting or regular short-acting opioids, supplemented by as-needed (PRN) breakthrough dosing. PRN-only dosing is inadequate for chronic cancer pain because it results in: (1) 'Pain troughs' — periods of severe pain as blood levels fall between doses; (2) 'Dose spikes' — excessive sedation when blood levels peak after each PRN dose; (3) Anxiety — patients must experience significant pain before being medicated; (4) Undertreatment — patients hesitate to ask for medication or staff delay administration. ATC scheduled dosing maintains a therapeutic blood level plateau, preventing breakthrough pain and reducing overall opioid requirements. Short-acting 'rescue' or 'breakthrough' doses (typically 10–15% of the 24-hour opioid total) are given for episodic escalating pain.
Question 3: A child's morphine dose has been titrated up to 0.2 mg/kg/dose every 4 hours and she now has stable pain but is experiencing constipation. The nurse should anticipate which intervention?
- Initiate a scheduled stimulant laxative (senna or bisacodyl) as opioid-induced constipation does not resolve with tolerance and requires active management (Correct answer)
- Wait for tolerance to develop as constipation resolves within 1–2 weeks
- Recommend increased fluid and fiber intake as the sole intervention
- Reduce the opioid dose to treat the constipation
Correct answer: Initiate a scheduled stimulant laxative (senna or bisacodyl) as opioid-induced constipation does not resolve with tolerance and requires active management
Opioid-induced constipation (OIC) is caused by opioid binding to mu receptors in the GI tract, slowing motility. Unlike sedation, OIC does not develop tolerance and requires proactive, ongoing stimulant laxative therapy.
Opioid-induced constipation (OIC) is the most prevalent opioid side effect and notably does not diminish with tolerance over time — unlike sedation, nausea, and pruritis, which typically improve in 5–7 days. This is because mu-opioid receptors in the GI tract reduce peristalsis, increase water absorption, and cause sphincter dysfunction. Stimulant laxatives (senna, bisacodyl) are first-line treatment — they stimulate colonic motility directly. Docusate (stool softener) alone is inadequate and not recommended as monotherapy. Osmotic laxatives (polyethylene glycol, lactulose) can be added. For refractory OIC, methylnaltrexone (a peripheral opioid receptor antagonist that does not cross the blood-brain barrier) can be used in older children without affecting central analgesia. Adequate hydration and mobility are also important.
Question 4: Which adjuvant medication is most appropriate to add for a child with cancer pain from nerve compression causing neuropathic symptoms (burning, shooting pain)?
- Gabapentin (Neurontin) (Correct answer)
- Acetaminophen 1000 mg
- Ondansetron
- Diphenhydramine
Correct answer: Gabapentin (Neurontin)
Gabapentin (a gabapentinoid/anticonvulsant) blocks voltage-gated calcium channels in dorsal horn neurons, reducing neuropathic pain transmission. It is the first-line adjuvant for pediatric neuropathic cancer pain.
Adjuvant analgesics enhance pain control for specific pain types or mechanisms. Neuropathic pain in pediatric oncology (from nerve compression, tumor invasion, or chemotherapy-induced peripheral neuropathy) typically responds poorly to opioids alone. Gabapentin binds to the alpha-2-delta subunit of voltage-gated calcium channels in dorsal horn neurons, reducing excitatory neurotransmitter release and dampening neuropathic pain signaling. It is started at a low dose and titrated upward, monitoring for sedation and dizziness. Pregabalin has similar mechanism with potentially more predictable pharmacokinetics. Tricyclic antidepressants (amitriptyline) and duloxetine (SNRI) are alternatives. These adjuvants allow lower opioid doses while improving pain control — the 'opioid-sparing' effect reduces opioid side effects.
Question 5: When converting a child from IV morphine to oral morphine, the nurse should apply which pharmacokinetic principle?
- Oral morphine is approximately 3 times less potent than IV morphine due to first-pass hepatic metabolism, so the oral dose is 3 times higher than the IV dose (Correct answer)
- Oral and IV morphine are equivalent in potency and require no dose adjustment
- Oral morphine is more potent than IV morphine and requires a lower dose
- No conversion is needed as the opioid receptor response is the same regardless of route
Correct answer: Oral morphine is approximately 3 times less potent than IV morphine due to first-pass hepatic metabolism, so the oral dose is 3 times higher than the IV dose
Oral morphine undergoes significant first-pass metabolism in the liver, reducing its bioavailability to approximately 30–40% of the IV dose. The equianalgesic ratio is IV:PO = 1:3 — thus the oral dose is approximately 3 times the IV dose to achieve equivalent analgesia.
Equianalgesic dosing is essential when converting between opioid routes to maintain consistent pain control. Morphine's oral bioavailability is approximately 30–40% due to extensive first-pass hepatic metabolism (primarily to morphine-3-glucuronide and morphine-6-glucuronide). The equianalgesic ratio is IV morphine:oral morphine = 1:3 (some references use 1:2 to 1:3). Example: a child on IV morphine 2 mg every 4 hours → oral morphine approximately 6 mg every 4 hours. When switching to sustained-release oral morphine (e.g., MS Contin), calculate the 24-hour total and divide into 12-hourly doses, adding a short-acting IR formula for breakthrough pain (10–15% of 24-hour total per dose, as needed every 1–2 hours).
Question 6: A nurse receives an order for opioid analgesia for a child in cancer pain. Before administering, which assessment is most critical to perform and document?
- Respiratory rate and level of sedation using a validated sedation scale (Correct answer)
- Blood pressure and heart rate only
- Temperature and skin integrity
- Pupil size and oral mucosa assessment
Correct answer: Respiratory rate and level of sedation using a validated sedation scale
Opioids can cause respiratory depression — the most life-threatening side effect. Baseline and post-dose respiratory rate and level of sedation must be assessed and documented before and after opioid administration per safety standards.
Before administering an opioid analgesic, the nurse must assess and document: (1) Respiratory rate — must be ≥10 breaths/minute for most protocols (institutional parameters vary; commonly ≥8–10 in opioid-tolerant patients); (2) Level of sedation using a validated scale (e.g., Pasero Opioid-Induced Sedation Scale [POSS]: S=sleep, 1=awake, 2=drowsy, 3=frequently drowsy, 4=somnolent); (3) Current pain score; (4) Time and dose of last opioid administration. Post-dose reassessment of respiratory rate, sedation, and pain score is required at 15–30 minutes for IV opioids and 30–60 minutes for oral opioids. Oxygen saturation monitoring adds value but does not substitute for respiratory rate — SpO2 may remain normal after opioids until frank apnea occurs due to opioid effects on respiratory drive with maintained oxygen diffusion.
CPHON Pain Assessment and Management in Pediatric Oncology 2
A parent of a child with terminal cancer asks why morphine is being increased so frequently, saying: 'I'm afraid giving more pain medicine will make him die faster.' The nurse's most appropriate response addresses which ethical principle?