A prospective comparative study of two indirect methods for confirming the localization of an epidural catheter for postoperative analgesia
NLM Title Abbreviation
Anesthesia and Analgesia
DOI of Published Version
We prospectively evaluated, in randomized order, 2 indirect methods of confirming the localization of an epidural catheter for postoperative analgesia in 218 surgical patients: epidural stimulation test (EST) and epidural pressure waveform analysis (EPWA). The epidural space was localized by using a loss of resistance technique. All catheters were inserted 5 cm into the epidural space and primed with 5 mL of 0.9% normal saline. There were no differences between the methods: the positive predictive value and specificity were high (100% in both groups), but the sensitivity was moderate (80% for EST and 81% for EPWA) and the negative predictive value was low (16% for EST and 17% for EPWA). Combining both methods yielded better sensitivity (97%) and negative predictive value (57%) (P < 0.001). The sensitivity of EST was increased to 87% (P < 0.05) if sensory response was included as well as motor response for stimulation less than 10 mA. We suggest the inclusion of sensory response in the appropriate dermatome at a current <10 mA as a criterion for adequate epidural catheter localization for EST testing. EPWA sensitivity was significantly better with older patients: 94% for patients older than 80 yr compared with 63% for patients younger than 40, 73% for patients 40 to 60, and 85% for patients aged 60 to 80 yr (P = 0.03). We conclude that the two tests are comparable for confirming catheter placement.
Adult, Aged, Aged, 80 and over, Analgesia, Epidural/methods, Catheterization/methods, Electric Stimulation, Epidural Space, Female, Humans, Male, Middle Aged, Pain, Postoperative/prevention & control, Prospective Studies
Published Article/Book Citation
Anesthesia and Analgesia, 101:6 (2005) pp.1830-1833. DOI:10.1213/01.ANE.0000184130.73634.BE.