Dx: Managing the Femoral Nerve Block
On your ultrasound image, you have a clear view of the femoral vein medially, femoral artery just lateral to the vein, and a nice shot of the femoral nerve coursing just laterally to the femoral artery (Fig 3). You know it’s going to be tricky managing this patient’s pain given her hypotension and the severity of her injury. Any attempt at reducing her femur fracture or putting it into traction is going to be met with obscenities and further screaming. It would be cruel and unusual punishment to try to reduce this woman’s leg without any analgesia, and she is not an ideal candidate for sedation alone. On the ultrasound image, the femoral nerve is just screaming to be blocked, so you work on attempting an ultrasound guided fascia iliaca compartment block to help treat your patient’s pain.
With your probe resting just below the inguinal ligament, you find the femoral nerve, the femoral artery, and femoral nerve you are very familiar with from femoral venous access attempts. You can visualize the fascia lata, fascia iliaca, and iliopsoas muscle surrounding your femoral nerve and adjacent vessels (Figure 4). You note that the femoral nerve has branches above and below the fascia iliaca. You insert a long spinal needle under your probe and guide the tip towards the area just beneath the fascia iliaca surrounding the iliopsoas muscle. With anesthetic injected into this space, you are able to anesthetize the lateral femoral cutaneous nerve, the femoral nerve, and the obturator nerve.
Now that you see that your needle is in the right place under ultrasound guidance, you aspirate first to ensure you are not in a vessel, and then administer 40 mL of a lidocaine-bupivicaine mixture into the potential space. Within minutes, the patient’s demeanor becomes more calm and collected. Her pain is improving and she can now tolerate a quick reduction and traction applied to her right femur fracture. She thanks you and your team for all of your help, and promises to be a more understanding consultant the next time she is in your ED.
At that last comment, you turn to your trauma colleague with a puzzled look on your face. To which he replies “Yep, that’s the OB/Gyn attending you called to come evaluate your heavy vaginal bleeder in room 9.”
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