title: Intravenous morphine in postoperative infants: intermittent bolus dosing versus targeted continuous infusions.
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.
authors.affiliation: Department of Anesthesiology, University of Washington Schools of Medicine and Pharmacy, Seattle, WA, USA Department of Anesthesia and Critical Care, Children's Hospital and Regional Medical Center, Seattle, WA 98105, USA Department of Pharmaceutics, University of Washington Schools of Medicine and Pharmacy, Seattle, WA, USA.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Lynn
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Nespeca
authors.forename: Susan L
authors.initials: SL
authors.lastname: Bratton
authors.forename: Danny D
authors.initials: DD
authors.lastname: Shen
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D002245:Carbon Dioxide / Q000097:blood; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007260:Infusion Pumps; D007275:Injections, Intravenous; D008297:Male; D009020:Morphine / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D009022:Morphine Derivatives / Q000097:blood; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D010149:Postoperative Pain / Q000188:drug therapy*; D012119:Respiration / Q000187:drug effects; D014680:Veins
chemical_list: D000701:Analgesics, Opioid; D009022:Morphine Derivatives; D002245:Carbon Dioxide; C035349:morphine-6-glucuronide; D009020:Morphine; D010100:Oxygen