Intravenous morphine in postoperative infants: intermittent bolus dosing versus targeted continuous infusions

Pain. 2000 Oct;88(1):89-95. doi: 10.1016/S0304-3959(00)00313-4.

Abstract

Eighty-three infants received i.v. morphine following surgery as a continuous infusion to a targeted morphine concentration of 20 ng ml(-1) (n = 56) or as intermittent bolus doses as needed (n = 27). Ventilation was compared in the two groups by continuous pulse oximetry, by venous blood gases on postoperative day 1 (POD 1) and by CO2 response curves. Infant pain scores were done to assess analgesia every 4 h. Both groups achieved pain scores consistent with analgesia but the bolus group showed a higher percentage of pain scores indicating distress (32 vs. 13%, P < 0.001). Room air saturations of < 90% were seen for 2.3% of POD1 in infusion-treated infants and for 2.5% of POD1 in bolus-treated infants. Mean venous PCO2S were normal in the two groups. Four infants showed ventilatory effects in the infusion group (4/ 56 = 7%); venous hypercarbia in two (2 days, 36 days), oximetry desaturation in one (240 days), both effects in one (6 days). Ventilatory effects were not statistically different between the intermittent bolus-treated and infusion-treated infants but may be clinically important. Monitoring with continuous oximetry is necessary. Morphine clearance increased with age. Infants with detectable morphine also had measurable morphine-6-glucuronide in both groups. Oral intake began at 16 h in both groups and other side effects were infrequent.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Analgesics, Opioid / administration & dosage*
  • Analgesics, Opioid / adverse effects
  • Analgesics, Opioid / pharmacokinetics
  • Analgesics, Opioid / therapeutic use
  • Carbon Dioxide / blood
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Infusion Pumps
  • Injections, Intravenous
  • Male
  • Morphine / administration & dosage*
  • Morphine / adverse effects
  • Morphine / pharmacokinetics
  • Morphine / therapeutic use
  • Morphine Derivatives / blood
  • Oximetry
  • Oxygen / blood
  • Pain, Postoperative / drug therapy*
  • Respiration / drug effects
  • Veins

Substances

  • Analgesics, Opioid
  • Morphine Derivatives
  • Carbon Dioxide
  • morphine-6-glucuronide
  • Morphine
  • Oxygen