PARTURIENTS POSTURE DURING EPIDURAL PUNCTURE AFFECTS THE DISTANCE FROM SKIN TO EPIDURAL SPACE

Study Objective: To assess the factors affecting the distance from skin to epidural space. Design: Prospective observational study of consecutive cases over a 2-year period. Setting: Inpatient obstetric unit :in a French university hospital. Patients: 2,123 consecutive term parturients who received epidural anesthesia for cesarean section or epidural analgesia for labor and vaginal delivery. Interventions: At the time of epidural puncture, the interspace used and the patient's posture (sitting or left lateral decubitus) were recorded, and the distance from the skin to the epidural space (DS-ES) was measured to the nearest 0.5 cm using a marked epidural needle. Measurements and Main Results: The relationship between patient factors [height, weight, body mass index (BMI; weight/height(2)), presence of scoliosis] and technical factors (interspace, patient's posture at puncture) versus DS-ES was investigated using multiple repression analysis. DS-ES correlated positively with the parturient's weight and BMI. In addition, DS-ES war significantly greater when epidural puncture was performed in the lateral position as compared with the sitting position. Conclusion: Both the patients weight and position. during epidural needle placement are important factors influencing DS-ES. A change from the sitting to the lateral position may increase DS-ES, causing catheter dislodgment and consequent inadequate analgesia. Clinical studies relating DS-ES to inadequate analgesia must take these factors into account.