Recurrent hypoxia in rats during development increases subsequent respiratory sensitivity to fentanyl
Immanuela Ravé Moss1, Karen A Brown, André Laferrière
1Departments of Pediatrics and Physiology, McGill University, The Montreal Children's Hospital, 2300 Tupper Street, Montreal, Quebec H3H 1P3, Canada. immanuela.moss@mcgill.ca
Insights
Recurrent hypoxia, common in severe obstructive sleep apnea, increases respiratory sensitivity to opioids like fentanyl in developing rats. This suggests caution is needed when prescribing pain medication to children with a history of sleep apnea to prevent respiratory depression.
Area of Science:
- Pediatric Anesthesiology
- Respiratory Physiology
- Sleep Medicine
Background:
- Postsurgical opioid use in children with obstructive sleep apnea (OSA) is linked to respiratory complications.
- Recurrent hypoxemia from severe OSA may alter the response to exogenous opiates.
Purpose of the Study:
- To investigate the effect of recurrent hypoxia in developing rats on respiratory responses to fentanyl, a mu-opioid agonist.
- To determine if prior exposure to hypoxia alters sensitivity to subsequent opioid administration.
Main Methods:
- Developing rats were exposed to intermittent hypoxia (12% O2) for 17 days.
- Following a recovery period, rats received fentanyl, and respiratory responses were measured using whole-body plethysmography.
- Control rats underwent the same procedures without hypoxia exposure.
Main Results:
- Rats with prior hypoxia exposure exhibited significantly greater respiratory depression (minute ventilation, respiratory frequency, tidal volume) in response to fentanyl compared to controls.
- These findings indicate enhanced respiratory sensitivity to fentanyl following recurrent hypoxia.
Conclusions:
- Previous recurrent hypoxia exposure increases respiratory sensitivity to subsequent opioid agonists.
- Clinical implications suggest that opioid dosing in children may need adjustment based on their history of recurrent hypoxemia to mitigate the risk of respiratory depression.
Background:
In children with a history of significant obstructive sleep apnea who undergo adenotonsillectomy, postsurgical administration of opiates has been alleged to be associated with an increased risk for respiratory complications, including respiratory depression. The authors hypothesize that this association is due to an effect of recurrent hypoxemia that accompanies more severe obstructive sleep apnea on altered responsiveness to subsequent exogenous opiates.
Methods:
The current study was designed to test the effect of recurrent hypoxia in the developing rat on respiratory responses to subsequent administration of the mu-opioid agonist fentanyl. Rats were exposed to 12% oxygen balance nitrogen for 7 h daily for 17 days, from postnatal day 17 to 33, a period equivalent to human childhood. After 17 additional days in room air, rats were given a fentanyl dose and tested for their respiratory response to fentanyl using a whole body plethysmograph. Rats undergoing similar protocols without recurrent hypoxia served as controls.
Results:
As compared with controls, rats preexposed to recurrent hypoxia displayed a more profound depression with fentanyl in minute ventilation, respiratory frequency, tidal volume, and tidal volume divided by inspiratory time that represents respiratory drive. These results indicated an increased respiratory sensitivity to fentanyl after recurrent hypoxia.
Conclusions:
Previous recurrent hypoxia increases respiratory sensitivity to subsequent opiate agonists. If these findings are applicable to humans, opiate dosing in children must be adjusted depending on history of recurrent hypoxemia to avoid respiratory depression.
