Sensory assessment of epidural block for Caesarean section: a systematic comparison of pinprick, cold and touch sensation.
OBJECTIVE
Comparisons between the profile of regional blocks are difficult to make because different methods of testing are used among the studies. The aims of this prospective study were to describe the profile of epidural block by using a scoring system to evaluate the density of the block as assessed by the loss to pinprick, cold and touch sensation; to evaluate the extent of differential block and to determine whether there is any relationship between these three modalities of testing.


METHODS
We studied 85 parturients undergoing elective Caesarean delivery with epidural anaesthesia with pH adjusted lidocaine 2% with epinephrine 1:400,000 and sufentanil 10 microg. Assessment of sensory block was done in each dermatomal level bilaterally for loss to pinprick, cold and light touch sensation and the density of the block was evaluated on an ordinal scale every 5 min for 20 min and thereafter at 30 and 40 min.


RESULTS
We observed a two dermatomes differential block between the complete loss of cold sensation being cephalad and the complete loss of both pinprick and light touch sensation being caudal. We established a significant correlation between the scores used to assess the density of the block in the three different modalities by considering the pinprick score as reference (Spearman's rank correlation is 0.94, P<0.001 for pinprick vs. cold, 0.97, P<0.001 for pinprick vs. light touch).


CONCLUSIONS
By scoring the density of the block on an ordinal scale, knowing the level of the block to pinprick allows one to predict the level of the block to touch and vice versa.
Camorcia
M
M
Città di Roma Hospital, Department of Anaesthesia, Roma, Italy. michela_camorcia@yahoo.it
Capogna
G
G
D000328:Adult; D000767:Anesthesia, Epidural / Q000379:methods*; D000773:Anesthesia, Obstetrical / Q000379:methods*; D002585:Cesarean Section; D003080:Cold Temperature; D005260:Female; D006801:Humans; D011247:Pregnancy; D013997:Time Factors; D014110:Touch / Q000187:drug effects* / Q000502:physiology*