Assessment of sensory block during labour epidural analgesia: a prospective cohort study to determine the influence of the direction of testing.

PURPOSE

Assessment of sensory block level during labour epidural analgesia is an essential component of clinical practice and patient safety. Nevertheless, the methods and direction of testing are not standardized. In our hospital, sensory block testing to ice is routinely used, but while some anesthesiologists test the block from a nonanesthetized to an anesthetized area, some do it in the opposite direction. It is unknown how these two different practices affect identification of the sensory block level. The objective of this study was to determine the agreement between these two practices.

METHODS

We enrolled 31 patients admitted to the labour and delivery unit in a prospective cohort study. At their request, labour epidural analgesia was performed as per institutional routine. Sensory block level to ice was assessed using opposite directions by two randomly assigned independent investigators, one and two hours after the loading dose was administered.

RESULTS

Sensory block levels to ice assessed from an anesthetized area to a nonanesthetized area were lower than those when assessed with the stimulus applied in the opposite direction, typically one segment lower.

DISCUSSION

Given the small difference detected with both methods, it may be acceptable to use either in clinical practice. Nevertheless, the lack of standardization may have a significant impact when comparing studies involving assessment of sensory block to ice.

STUDY REGISTRATION

www.

CLINICALTRIALS

gov (NCT03572439); registered 28 June 2018.