Morphine pharmacokinetics during continuous infusion of morphine sulfate for infants receiving extracorporeal membrane oxygenation.
OBJECTIVE
To determine a) if serum morphine concentration changes during the first 3 hrs of extracorporeal membrane oxygenation (ECMO); and b) if absorption of morphine onto the membrane oxygenator is responsible for these changes. Also, morphine clearance during the first 5 days of ECMO was studied.


METHODS
Prospective, open-label study with consecutive patient enrollment.


METHODS
Neonatal intensive care unit at a university-affiliated, children's hospital.


METHODS
Eleven neonates with severe persistent pulmonary hypertension of the newborn receiving continuous intravenous infusions of morphine sulfate and requiring ECMO.


METHODS
Blood samples were obtained from the subjects and ECMO circuits at predetermined time intervals.


RESULTS
Serum morphine concentration was determined using high-performance liquid chromatography. Morphine concentrations were no different from baseline at 5 mins, 1 hr, or 3 hrs after beginning ECMO. There was no significant difference in morphine concentration from samples taken immediately proximal and distal to the membrane oxygenator at 5 mins, 1 hr, and 3 hrs after the start of ECMO. Morphine clearance was calculated on days 1, 3, and 5 of ECMO. The mean value for morphine clearance was 11.7 +/- 9.3 (SD) ml/min/kg (range 2.6 to 34.5).


CONCLUSIONS
The initiation of ECMO does not lead to a significant decrease in serum morphine concentration and there is no uptake of morphine onto the membrane oxygenator of the ECMO circuit. Morphine clearance for infants receiving ECMO is variable.
Geiduschek
J M
JM
Department of Anesthesiology, University of Washington School of Medicine, Children's Hospital and Medical Center, Seattle 98105, USA.
Lynn
A M
AM
Bratton
S L
SL
Sanders
J C
JC
Levy
F H
FH
Haberkern
C M
CM
O'Rourke
P P
PP
D002851:Chromatography, High Pressure Liquid; D015199:Extracorporeal Membrane Oxygenation; D005865:Gestational Age; D006801:Humans; D006976:Hypertension, Pulmonary / Q000378:metabolism* / Q000628:therapy*; D007231:Infant, Newborn; D007262:Infusions, Intravenous; D007363:Intensive Care Units, Neonatal; D008657:Metabolic Clearance Rate; D009020:Morphine / Q000097:blood / Q000493:pharmacokinetics*; D011446:Prospective Studies
D009020:Morphine