RESUMEN
This randomized control trial was performed in 60 obstetric patients scheduled for cesarean section under regional anesthesia. They were randomly allocated into two groups. Group 1, the control group, were positioned by giving verbal instructions. Group 2, the visual-aided group, were positioned by giving verbal instructions plus showing them photographs of the standard position for an epidural block. The nurse anesthetist, who did not know the method used for positioning, was called into the operating room and readjusted the patient's position as necessary, and evaluated the previous positioning as; very good, good or unsatisfactory. The anesthesiologist, who also did not know which method had been used, palpated the patient's interspinous space before and after any adjustment by the nurse anesthetist and recorded the difference in the space width following adjustment, which was categorized into 3 grades; wider, no change, and narrower. The results showed a significantly better initial position using photographs (very good = 73.4%, good = 23.3%, and unsatisfactory = 3.3%) compared to the control group (very good = 3.3%, good = 46.7% and unsatisfactory = 50%), p < 0.0001. The adjustment of positioning which increased the interspinous width in the visual-aided group (30%) was significantly less than in the control group (56.7%). No change needed in positioning was more common in the study group (60%) than in the control group (36.6%). This meant that visual-aided positioning needed readjustment significantly less than those positioned by the conventional method. The average time used to identify the epidural space using the loss of resistance technique and the average number of needle insertions in the visual-aided group were less than in the control group, but this was not statistically significant. Successful epidural block in the visual-aided group (96.7%) was higher than in the control group (90%) but this was not statistically significant. We conclude that the photographs of the standard position for epidural block can be use as a visual aid to improve positioning in obstetric patients scheduled for cesarean section.