Placebo Versus Nocebo: Effects on Pain and Anxiety During Local Anaesthetic Infiltration in Parturient Undergoing Elective Caesarean Delivery

This randomized trial compared placebo and nocebo effect over anaesthetist-patient communication on pain and anxiety score during local anaesthetic (LA) skin infiltration in parturient undergoing caesarean delivery under regional anaesthesia (RA). A secondary objective was to determine if education level and previous RA experience affect pain and anxiety scores. Parturients scheduled for elective caesarean delivery were randomised into Placebo (P) or Nocebo (N) group. Baseline Amsterdam Preoperative Anxiety \& Information Scale (APAIS0) were obtained. Standardised scripts describing the LA skin infiltration for RA were used during the pre-anaesthetic review. (N) group were explained with words like "pain, prick, sharp" while words like "numb, comfort, tolerable" were used in the (P) group, avoiding "painful" expressions. The same scripts will be repeated before skin infiltration during the RA procedure. On the day of surgery, a second (APAIS1) was obtained upon arrival to the theatre. Pain score using the numerical rating scale (NRS) was assessed after LA infiltration.