Characterizing patterns of sensory loss during labor epidural analgesia: a prospective study of breakthrough pain

Abstract

Background

Two distinct levels of sensory loss can be detected while assessing the cephalad spread of epidural analgesia during labor: the level of complete sensory loss (cephalad dermatome with complete sensory loss to a testing stimulus) and the level of partial sensory loss (cephalad dermatome of partial sensation to the same stimulus). This study sought to determine the levels of complete and partial sensory loss in patients experiencing breakthrough pain and how they change after re-establishment of analgesia.

Methods

We conducted an exploratory prospective cohort study to compare the levels of complete and partial sensory loss, to both ice and pinprick, at a time when patients experienced breakthrough pain and after effective analgesia was re-established.

Results

We enrolled 30 patients. The median [interquartile range] level of complete sensory loss to ice increased from T12 [L1–T10] while in pain to T10 [T11–T9] after analgesia was re-established. The median level of complete sensory loss to pinprick increased from T12 [L2–T11] while in pain to T11 [T12–T10] after analgesia was re-established. The median level of partial sensory loss to ice and pinprick was above T10 both before and after top-up.

Conclusion

Patients experiencing breakthrough pain had a level of complete sensory loss to ice and pinprick below T10. After re-establishment of analgesia, the level of complete sensory loss to ice increased to T10 or above suggesting the level of complete sensory loss to ice may be the preferred mode of assessment of labor epidural analgesia to ensure optimal analgesia. Study registration: www.clinicaltrials.gov (NCT05881395); registered 31st May 2023.