Disposition and respiratory effects of intrathecal morphine in children.
Publication/Presentation Date
10-1-1993
Abstract
BACKGROUND: The extent and duration of respiratory depression after opioid administration are poorly defined in infants and children.
METHODS: The disposition and respiratory effects of intrathecal morphine were studied in ten patients (ages 4 months-15 yr) after repair of craniofacial defects. Morphine, 0.02 mg/kg, was administered intrathecally before the end of surgery. Postoperatively, we determined the minute ventilation (VE) in response to increasing partial pressure of end-tidal carbon dioxide (PETCO2) during carbon dioxide rebreathing. The slope (VE/PETCO2) and intercept (VE at PETCO2 60 mmHg, VE 60) of the carbon dioxide response curve were calculated at 6, 12, and 18 h after morphine administration. Cerebrospinal fluid (CSF) and blood were analyzed for morphine concentration by radioimmunoassay.
RESULTS: Mean VE/PETCO2 decreased from a preoperative value of 35.1 +/- 3.7 to 16.3 +/- 2.8 ml.kg-1 x min-1 x mmHg-1 at 6 h after morphine, and remained depressed to 23.4 +/- 2.9 and 23.5 +/- 3.3 ml.kg-1 x min-1 x mmHg-1 at 12 h and 18 h, respectively, compared to preoperatively). The infants' (n = 3) VE/PETCO2 at 6 h were 21, 4, and 27 ml.kg-1 x min-1 x mmHg-1. Mean VE 60 decreased from 874 +/- 125 to 276 +/- 32 ml x kg-1 x min-1 at 6 h, but then recovered at 12 and 18 h to 491 +/- 68 and 567 +/- 82 ml.kg-1 x min-1, respectively. The infants' VE 60 at 6 h were 350, 142, and 245 ml.kg-1 x min-1. Mean CSF morphine concentration was 2,860 +/- 540 ng/ml at 6 h, and decreased to 640 +/- 220 and 220 +/- 150 ng/ml at 12 and 18 h, respectively.
CONCLUSIONS: Intrathecal morphine, 0.02 mg/kg, depressed the ventilatory response to carbon dioxide for up to 18 h concomitant with increased CSF morphine concentrations. Infants (4-12 months of age) did not exhibit greater ventilatory depression than did children (2-15 yr of age).
Volume
79
Issue
4
First Page
733
Last Page
738
ISSN
0003-3022
Published In/Presented At
Nichols, D. G., Yaster, M., Lynn, A. M., Helfaer, M. A., Deshpande, J. K., Manson, P. N., Carson, B. S., Bezman, M., Maxwell, L. G., & Tobias, J. D. (1993). Disposition and respiratory effects of intrathecal morphine in children. Anesthesiology, 79(4), 733–25A.
Disciplines
Medicine and Health Sciences | Pediatrics
PubMedID
8214752
Department(s)
Department of Pediatrics
Document Type
Article