Can parturients identify the midline during neuraxial block placement?

Abstract Study Objective To determine whether parturients can reliably identify their midline during epidural or spinal needle insertion, and to determine whether parturient feedback helps the anesthesiologist successfully identify the midline. Design Survey instrument completed by anesthesiologists. Setting Labor and delivery unit of a university-based, tertiary-care hospital. Measurements Completed questionnaires were obtained for 554 of 904 (61.3%) neuraxial blocks. Data were collected on the type of neuraxial block, number of needle redirections required to identify the midline, the patient's height and weight, the patient's position during block placement, whether the patient was questioned for assistance identifying the midline, and if so, how helpful the patient was in redirecting the needle to locate the epidural or subarachnoid space. Main Results The anesthesiologist requested the assistance of 194 patients (35.0%) for needle location. Of those questioned, the anesthesiologist reported 128 instances (66.0%) when the patient's response was helpful in identification of the midline. Morbidly obese parturients (BMI > 35 kg/m2 ) were questioned more often than their non-morbidly obese counterparts (48.9% vs. 30.5%; P < 0.0005). Of those morbidly obese parturients who were questioned (n = 64), 76.6% were reported by the anesthesiologist to be helpful. Conclusions Most patients, including morbidly obese patients, are helpful in identifying the midline during neuraxial anesthesia.