Discussion
myopia, blood intravascular, paresthesia, Paresthesia
MYOPIA, PARESTHESIA, PARESTHESIA, COMPLICATIONS
The present study demonstrated that the table height (at the umbilicus, lowest rib margin, and xiphoid process level of the residents administering CSEA) did not influence the success rates of CSEA and epidural space puncture. The table height also did not influence the incidence of complications of CSEA, including paresthesia and blood intravascular cannulation. Paresthesia was more likely to occur on the left side than the right side when the catheter was inserted into the epidural space. The table height at which the needle insertion point was level with the operator’s lowest rib margin was preferred by most residents; this height was also best during training to administer epidural space puncture.In our study, the success rate of epidural space puncture administered by residents was 68.3%, consist with Drake et al. reported a success rate of 63–90% [Paresthesia was more likely to appear on the left side than the right side when the catheter was inserted into the epidural space, but there was no difference between sides in the incidence of paresthesia during the advancement of the spinal needle. This may be because the residents were more likely to insert the epidural needle near the left side of the patient, and so the nerve roots on the left side of the epidural space were more likely to be irritated and cause paresthesia when the catheter was inserted. The catheters used in our study were stiff, which may have induced greater incidence of paresthesia and intravascular cannulation than wire-embedded catheters [Diagrammatic sketch of combined epidural-spinal anesthesia administrated by most residentsThere was no relationship between the success rates of CSEA and the residents’ age, height, BMI, sex, experience level, and myopia. Similarly, these factors had no influence on the incidence of paresthesia. This suggests that the demographic characteristics of the residents did not influence their ability to administer CSEA during training; the effectiveness of their training was only influenced by their degree of comfort during the process of performing epidural anesthesia. In contrast, a previous study showed that the resident’s experience level significantly affected the incidence of paresthesia during the advancement of a thoracic epidural catheter [The table height most favored by residents was that at which the puncture point was at the same height as their lower rib margin, as this height was considered more comfortable and thus favorable for the performance of successful CSEA. A working surface height that ranges from 10 cm below to 5 cm above the elbow is optimal for standing workers [The present study had some limitations. First, the number of CSEA procedures performed varied between residents. This was because each resident was assigned to a different surgery room, and the number of CSEA procedures performed by each resident was dependent on the surgeries scheduled on that day. At least 20–25 epidural blocks are reportedly necessary to achieve consistency during residency training in anesthesiology [