The volume of blood for epidural blood patch in obstetrics: a randomized, blinded clinical trial.

BACKGROUND Our aim in this multinational, multicenter, randomized, blinded trial was to determine the optimum of 3 volumes of autologous blood for an epidural blood patch. METHODS Obstetric patients requiring epidural blood patch after unintentional dural puncture during epidural catheter insertion were allocated to receive 15, 20, or 30 mL of blood, stratified for the timing of epidural blood patch and center. Participants were followed for 5 days. The primary study end point was a composite of permanent or partial relief of headache, and secondary end points included permanent relief, partial relief, persisting headache severity, and low back pain during or after the procedure. RESULTS One hundred twenty-one women completed the study. The median (interquartile range) volume administered was 15 (15-15), 20 (20-20), and 30 (22-30) mL, with 98%, 81%, and 54% of groups 15, 20, and 30 receiving the allocated volume. Among groups 15, 20, and 30, respectively, the incidence of permanent or partial relief of headache was 61%, 73%, and 67% and that of complete relief of headache was 10%, 32%, and 26%. The 0- to 48-hour area under the curve of headache score versus time was highest in group 15. The incidence of low back pain during or after the epidural blood patch was similar among groups and was of low intensity, although group 15 had the highest postprocedural back pain scores. Serious morbidity was not reported. CONCLUSIONS Although the optimum volume of blood remains to be determined, we believe these findings support an attempt to administer 20 mL of autologous blood when treating postdural puncture headache in obstetric patients after unintentional dural puncture.