The Possibility of blocking the femoral nerve under ultrasound control with the use of the electrical stimulator of the peripheral nerves with small doses of ropivacaine

Goal. The aim of the study is to determine the possibility of using small volumes of ropivacaine for blockade of the femoral nerve performed with the use of an electrostimulator of peripheral nerves under ultrasound.

Materials and methods. 44 blockages of the femoral nerve were performed under ultrasound control with the use of electrical stimulation of the peripheral nerves. In the first group (22 patients), a blockade of the femoral nerve was performed with 10 ml of 0.75% ropivacaine; in the second group (22 patients), 0.75% ropivacaine was used in a volume of 5 ml. Evaluation of the development time of the sensory, motor blocks and the duration of analgesia was carried out from the time the local anesthetic solution was introduced into the fascial sheath of the femoral nerve.

Results. The time of development of the complete sensory block in the 1st and 2nd groups of patients was 21 (20; 24) minutes and 30 (24; 35) minutes (p <0.05). The time of development of the full motor block in the 1st group was 22 (16; 24) minutes; in the second group, 21 (17; 30) minutes (p <0.05). There was no difference in the duration of analgesia in the postoperative period between the groups: 7.75 (7; 8) h and 8 (7.5, 8) h. respectively (p> 0.05).

Conclusion. It has been established that 5 ml of 0.75% solution of ropivacaine is sufficient for effective blockade of the femoral nerve. With a decrease in the effective amount and volume of local anesthetic, there is an increase in the time of development of complete blockade of the femoral nerve without reducing the period of postoperative analgesia.