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The dose-effect relationship for morphine and vomiting after day-stay tonsillectomy in children

B J Anderson1, C J Ralph, A W Stewart

  • 1Department of Anaesthesia, Auckland Children's Hospital, Grafton, New Zealand.

Anaesthesia and Intensive Care
|May 2, 2000
PubMed

Insights

Lower morphine doses significantly reduce vomiting in children after tonsillectomy. Doses above 0.1 mg/kg increase the risk of postoperative nausea and vomiting (PONV), necessitating careful dose selection for pediatric day-stay surgery.

Area of Science:

  • Pediatric Anesthesiology
  • Pharmacology
  • Pain Management

Background:

  • Postoperative nausea and vomiting (PONV) is a common complication in children undergoing day-stay surgery.
  • Intravenous morphine is frequently used for analgesia but can increase the risk of PONV.
  • Optimizing morphine dosage is crucial for balancing pain relief and side effects in pediatric tonsillectomy patients.

Purpose of the Study:

  • To investigate the dose-response relationship between intravenous morphine and the incidence of vomiting in children undergoing day-stay tonsillectomy.
  • To determine the pharmacodynamic parameters for morphine-induced vomiting and hospital admission due to vomiting.
  • To establish optimal morphine dosing strategies to minimize PONV in this pediatric population.

Main Methods:

  • Retrospective chart review of 164 pediatric patients undergoing day-stay tonsillectomy.
  • Analysis of morphine administration (0.09 mg/kg mean dose) versus no opioid.
  • Logistic regression used to model the probability of vomiting and overnight hospital stay based on morphine dose.

Main Results:

  • Fifty-five of 164 children experienced vomiting; 20 required overnight admission due to PONV.
  • A morphine dose of 0.1 mg/kg was associated with a 50% probability of vomiting and a 10% probability of admission.
  • Pharmacodynamic estimates indicated ED50 values of 0.18 mg/kg for vomiting and 0.369 mg/kg for overnight stay.

Conclusions:

  • Morphine doses exceeding 0.1 mg/kg are linked to a higher incidence of PONV in pediatric tonsillectomy patients.
  • Lower doses of morphine are associated with a reduced incidence of emesis following tonsillectomy.
  • This study supports the use of lower morphine doses to improve outcomes in pediatric day-stay tonsillectomy, minimizing PONV and associated hospital admissions.

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