The Optimal Volume Selection of Ropivacaine Solution for The Quadriceps Muscle Bilateral Blockage for Pain Relief After Cesarean Section Surgery: A Prospective Randomized Cohort Study

BACKGROUND: Pain after cesarean section is still an urgent issue in obstetric anesthesiology, as it increases the risk of postoperative complications. This problem is still relevant despite the introduction of modern methods of postoperative analgesia. The use of regional analgesia methods as a leading component of multimodal pain management, reduces the side effects of medications and is an attractive tool, especially when used after cesarean section surgery.

AIM: To evaluate the effect of the volume of local anesthetic during bilateral QLB 3 on the effectiveness of analgesia in women after cesarean section.

MATERIALS AND METHODS: A prospective single-center randomized cohort study was conducted with 94 women who underwent postoperative analgesia by blockage of the third type of quadratic lumbar muscle with a 180 mg solution of ropivacaine. The patients were randomized into 3 groups: A (n=31) - dilution of local anesthetic in a volume of 30 ml; B (n=30) - in 40 ml and C (n=32) - in 20 ml. The quality and duration of anesthesia and the area of the analgesia zone were evaluated during the study. The cold test method and a visual analog scale were used for the assessment. The evaluation was carried out at rest and during movement. The need for additional analgesia was also assessed.

RESULTS: Analgesia zones are noted only at the Th11-Th12 level in most patients of group C(20 (60%), whereas in group B more than half of the patients (18(56%)) noted analgesia at all levels, group A was an intermediate variant between these extreme results. The results indicate that the length of the block depends on the volume of the injected local anesthetic. The quality of analgesia was higher in the groups where a larger volume of local anesthetic was used than in the groups with a smaller volume. The differences in analgesia quality scores between the study groups were statistically significant.

CONCLUSION: The results of a comparative study of three volumes of the standard dose of ropivacaine for postoperative analgesia in patients after cesarean section by blockage of the quadratic muscle of the lower back showed the highest effectiveness with a dilution volume of 40 ml, which indicates the effect of the volume of solution on the quality of anesthesia.