Intact proprioception and control of labour pain during epidural analgesia

Background: Accurate proprioception is critical while walking, yet an ambulatory epidural regimen that provides adequate analgesia for labour while simultaneously preserving proprioceptive input has not been described. Methods: Sixty primigravidae in established labour received bupivacaine 15 mg (15 ml of 0.1% w/v) and fentanyl 100 mu g through a lumbar epidural catheter. Clinical assessment of dorsal column sensory function included: vibration sense, distal proprioception and the Romberg test, and were all performed before catheter insertion and 30 min after the study bolus. Sensory modalities were also tested compared to an unblocked dermatome. Pain was scored on a 0-10 cm visual analogue scale (VAS) before and 30 min after induction. Intensity of the motor block was tested using a modified Bromage score (grade 1-6). Results: The study bolus provided reliable analgesia with 43 parturients attaining a VAS pain score of zero. Mean duration of analgesia was 67.5 min (SD 22.85). All parturients retained the ability to perform a partial knee bend while standing (grade 6). No mothers exhibited impaired distal proprioception, altered vibration sense or a positive Romberg sign. Conclusion: This study confirms that the addition of lumbar epidural fentanyl 100 mu g to 15 mg of epidural bupivacaine provides good control of labour pain with no motor block and establishes that this combination preserves dorsal column sensory function.