Drip infusion method as a useful indicator for identification of the epidural space / 대한마취과학회지

BACKGROUND: Cervical epidural anesthesia (CEA) is used for pain control and surgical procedures of the head and neck or upper arm areas. However, the failure rate of CEA is reported to be high, is the failure rate being quite higher than other sites, because of the anatomical differences of the cervical spine. We hypothesized that the loss of resistance (LOR) method combined with the drip infusion method for confirmation of the cervical epidural space can reduce the failure rate. This study investigated the usefulness of the drip infusion method. METHODS: One hundred chronic renal failure patients undergoing arteriovenous bridge graft for hemodialysis at the upper arm under cervical epidural anesthesia were recruited for this study. In the cervical epidural puncture, we identified the cervical epidural space using a combination of the LOR method with the drip infusion method. After confirmation of the epidural space with LOR method, we decided it was the true epidural space when fluid dripping to the space was present. Otherwise, if fluid dripping was not present, we designated it was pseudo LOR, and we found the true epidural space using the drip infusion method only. RESULTS: In all cases, the combined LOR with drip infusion method, identify the epidural space. CONCLUSIONS: Combined LOR with drip infusion method is an efficacious method for the confirmation of the cervical epidural space.

Comparison of Methods to Confirm the Cervical Epidural Space

BACKGROUND: The loss of resistance (LOR) method is most commonly used to identify the epidural space. This method is thought to rely on the penetration of the ligamentum flavum. Unfortunately the exact morphology of the ligamentum flavum is variable at different vertebral levels. Especially, it has been pointed out that the lower cervical ligamentum flavum may be discontinuous in the midline in up to 50% of patients. Thus, the LOR method may be inaccurate to confirm the cervical epidural space. The aim of this study is to determine which method is the safest and most exact for confirming the cervical epidural space. METHODS: 100 adult, chronic renal failure patients who were undergoing an arteriovenous bridge graft for hemodialysis at the upper arm under cervical epidural anesthesia were recruited for this study. During the cervical epidural puncture, we identified the cervical epidural space by subjectively feeling the resistance with using a finger just through the ligamentum flavum, and we also used the drip infusion method, the loss of resistance method using air, and the hanging drop method. By using 5 grades, we classified the extent of whether or not the techniques were effective. RESULTS: Using the drip infusion method, we identify the epidural space in all the patients as +/++ grade. The catheter insertion method was also successful in identifying those epidural spaces over a +/- grade. The pseudo LOR was over micro grade in 47 patients. CONCLUSIONS: The combined LOR/hanging drop with drip infusion method is useful for confirming the cervical epidural space.