///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Assessment of sensory block level to cold during epidural analgesia for labor: poor degree of agreement between testing in opposite directions

Abstract Number: T2C-190
Abstract Type: Original Research

Eliane C. S. Soares MD, MSc, Fellowship in Obstetric Anesthesia1 ; Balki Mrinalini MD, MSc2; Downey Kristi MSc3; Xiang Y Ye MSc4; Jose Carvalho MD, PhD5

Introduction: Assessment of sensory block level (SBL) during epidural analgesia for labor is an essential component of clinical practice. Such assessment is not standardized. While some assess the block from anesthetized to non-anesthetized dermatomes, others assess it in the opposite direction. The objective of this study was to determine the degree of agreement between these two practices. We hypothesized that the degree of agreement would be high and that both techniques would identify the same SBL. Methods: We conducted a prospective cohort study in women receiving epidural analgesia for labor. The epidural catheter was placed at L3-L4 and women received a loading dose of 15 mL of bupi 0.125% with fentanyl 50mcg, followed by a PIEB regimen of bupi 0.0625% with fentanyl 2mcg/mL. Two investigators were randomized to perform bilateral assessments of the SBL to cold using a standard ice bag at 1 and 2 hours after the loading dose. They were blinded to each other’s results. We compared 2 methods of assessment: a) from anesthetized to non-anesthetized dermatomes (caudad-cephalad direction-UP) and b) from non-anesthetized to anesthetized dermatomes (cephalad-caudad direction-DOWN). In both methods, the C3 dermatome was used as control (baseline cold). We defined Upper SBL (USBL) as the highest dermatome with any detectable block to cold and Lower SBL (LSBL) as the highest dermatome with complete block to cold. The primary outcomes were the USBL and LSBL to cold at 1 and 2 hours after the loading dose. The degree of agreement in the primary outcomes was assessed using Kappa statistics. Results: We enrolled 30 women. The degree of agreement in the primary outcomes assessed by the two methods was poor-fair (estimated kappa 0.02 to 0.24). However, Spearman’s correlation coefficient and regression analysis revealed a strong linear relationship between the methods. The UP method typically showed lower or similar SBL when compared to the DOWN method. The USBL and LSBL were typically 2 dermatomes apart (Table 1). Conclusion: The SBL to cold assessed by the two methods are strongly correlated but their agreement is poor/fair. Given the small difference in SBL detected with both methods, it may be acceptable to use either in clinical practice. However, the lack of standardization may impact studies involving assessment of SBL to cold. The clinical implication of the difference between USBL and LSBL remains to be determined. Reference: Anaesthesia 2015;70:421-28

SOAP 2019