Canadian Journal of Anesthesia Volume 53, Number 1 / January, 2006
NEONATAL EFFECTS OF MATERNAL ANALGESIA AND
SEDATION WITH FENTANYL AND MIDAZOLAM
M. A. Froelich, T. Euliano, D. Caton
University of Florida, Gainesville, FL
Introduction: The study of drugs used during pregnancy is one of
the most neglected areas in the field of clinical pharmacology and
drug research. Analgesia and sedation, routinely used as adjunct
medication for regional anesthesia, is rarely used in the pregnant
patient because of concerns about adverse neonatal effect. We
studied neonatal and maternal effects of intravenous fentanyl and
midazolam prior to spinal anesthesia for elective Cesarean section.
We postulate that an intravenous bolus of midazolam and fentanyl
does not affect neonatal well-being.
Methods: After institutional approval, sixty healthy women
scheduled for elective Cesarean delivery where enrolled from
April 2001 until December 2003. Women were randomly assigned
to either receive a combination of 1 mcg/kg IV fentanyl and 0.02
mg/kg IV midazolam or an equal volume of intravenous (IV)
saline at the time of their skin prep for spinal anesthesia. Both
investigator and patient were blinded to the study drug. Patients
underwent spinal anesthesia with 12 mg hyperbaric bupivacaine,
10 mcg fentanyl and 300 mcg preservative-free bupivacaine. We
collected maternal and umbilical levels of fentanyl and midazolam
and maternal catecholamine levels (epinephrine and
norepinephrine). Fentanyl and midazolam levels were analyzed
using high performance lipid chromatography (HPLC). The
following neonatal data were recorded: Apgar scores, continuous
neonatal pulse oximetry for 3 hours and Scanlon neurobehavioral
scores (NACS). This study had more than 95% power (expected
difference of means and standard deviation: 1 Apgar score unit).
Results: Women in both groups were of similar height, weight and
age. Neonates of women who received fentanyl and midazolam did
not show different Apgar or NACS scores. Umbilical arterial and
venous levels of fentanyl and midazolam were below the limit of
quantification (less than 50 ng/mL) and neonates in either group
did not show significant oxygen desaturations during the first three
hours of life. Mothers in both groups were able to recall their birth.
Conclusion: Maternal analgosedation with fentanyl (1 mcg/kg) and
midazolam (0.02 mg/kg) prior to spinal anesthesia for elective
Cesarean section is without adverse neonatal effects.
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