Plasma norepinephrine levels, vagal tone index, and flexor reflex threshold in premature neonates receiving intravenous morphine during the postoperative period: A pilot study

L S Franck, W T Boyce, G A Gregory, J Jemerin, J Levine, C Miaskowski

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

Objective: The goal of this study was to evaluate the effects of a single dose of intravenous morphine on postoperative pain in extremely premature neonates after thoracotomy. Design: Descriptive correlational study. Patients: Twenty-four critically ill mechanically ventilated premature neonates with a mean gestational age of 26.1 +/- 2.1 (SD) weeks and a postnatal age of 13.8 +/- 8.1 (SD) days. Outcome Measures: Plasma norepinephrine (NE) levels, vagal tone index (VTI), and flexor reflex threshold were measured preoperatively, immediately before, and 20 and 60 minutes after the administration of the first postoperative dose of morphine (0.1 mg/kg). Results: One-way repeated-measures ANOVA revealed no significant change in plasma WE levels from baseline levels (df[2,32] = 2.40, p = 0.11). Pre- and post-morphine VTI values were significantly lower than preoperative values (fS[3,60] = 6.04, p = 0.0012), but no significant differences were found between pre- and post-morphine VTI values. Neonates (n = 10) who had a flexor reflex response during the postoperative period demonstrated no significant differences in the force required to elicit a flexor reflex across the four measurements (df[3,27] = 0.76, p = 0.53); however, the flexor reflex responses were significantly less vigorous during the post operative period than at baseline. Conclusions: Findings from this pilot study suggest that the dose of morphine commonly used to treat postoperative pain in premature neonates does not affect NE, VTI, and flexor reflex threshold values within 1 hour of administration.
Original languageEnglish
Pages (from-to)95 - 104
Number of pages10
JournalClinical Journal of Pain
Volume16
Issue number2
DOIs
Publication statusPublished - Jun 2000

Fingerprint

Dive into the research topics of 'Plasma norepinephrine levels, vagal tone index, and flexor reflex threshold in premature neonates receiving intravenous morphine during the postoperative period: A pilot study'. Together they form a unique fingerprint.

Cite this