Prehospital Ultrasound-Guided Pediatric Fascia Iliaca Block

A 7-year-old, 25-kg female was hit by a car traveling at approximately 50 km/h (30 mph) while crossing a road. There was a reported loss of consciousness for approximately 90 seconds. She complained of severe pain in her right thigh. Assessment by paramedics found her lying in the road 6 m from the car agitated and distressed but otherwise fully orientated without focal neurologic signs. Positive examination findings were a right frontal scalp contusion, right facial abrasions, and marked right thigh swelling consistent with a closed femoral shaft fracture. The primary survey was otherwise normal, and her vital signs were age appropriate. According to paramedic protocol, she was given repeated doses of intravenous morphine with the goal of extricating her from the road and application of a femoral traction splint. Despite a total of 10 mg morphine, she remained too distressed to be moved, and a helicopter emergency medical service (HEMS) team consisting of a flight physician and a critical care paramedic was tasked. The HEMS team administered titrated intravenous ketamine and midazolam in 0.5-mg and 10-mg increments for a total of 1.5 mg and 30 mg, respectively. This provided anxiolysis and analgesia and facilitated lifting from the road onto an ambulance stretcher set to kneeling height with a pelvic binder prepositioned. On-scene parental consent for regional anesthesia was obtained. The patient was positioned supine with her legs in the anatomic position, and the right inguinal area was cleaned with 70% isopropyl alcohol. Femoral triangle sonoanatomy was visualized via a linear probe using an iViz handheld ultrasound unit (FUJIFILM Sonosite, Inc, Bothell, WA), and a total of 9 mL 0.75% ropivacaine (2.7 mg/kg) was infiltrated deep to the fascia iliaca under ultrasound guidance through an echogenic plane block needle (SonoTAP; Pajunk Medical Systems, Alpharetta, GA) (Figure 1, Figure 2 and 2). Physiological monitoring included pulse oximetry, oscillometric blood pressure measurement, noninvasive capnography, and 3-lead electrocardiography. No symptoms or electrocardiographic features of local anesthetic toxicity were observed. A CT-6 traction splint (Faretec Inc, Painesville, OH) was applied, and the pelvis was bound (Fig. 3). The child was airlifted to a pediatric trauma center. En route she was offered further analgesia but declined, reporting no pain. The duration of prehospital care from the initial arrival of the emergency medical services to departing the scene was 59 minutes; 21 of those minutes were dedicated to HEMS team care. On assessment in the emergency department, she was alert and cheerful, and she reported her pain score as 0. There was no evidence of neurovascular compromise before or after splintage. Radiographs confirmed an isolated closed right femoral shaft fracture (Fig. 4); there were no other significant injuries. Operative fixation of the femur was performed the following day, and the postoperative course was uneventful.

Acute pain causes a stress response, resulting in physiological, biochemical, and behavioral changes in adults and children. Evidence suggests that severe pain in pediatric major trauma is often deprioritized and subject to oligoanalgesia, and pediatric long bone fracture presentations, in particular, receive suboptimal analgesia. This results in patient, staff, and parental distress; a delay in definitive management, and increasing risk of posttraumatic stress. There are additional considerations in the air medical environment that favor prehospital regional anesthesia. There is a decrease in the requirement for systemic analgesia that may depress the conscious level and respiratory function. Noise, vibration, and movement in flight can both exacerbate pain and impair the assessment of pain and analgesia requirements.

In our case, the patient's pain and distress exceeded the capacity of local pediatric paramedic analgesia protocols, which do not allow for pediatric ketamine administration. The HEMS team provided analgesic doses of ketamine, avoiding full dissociative sedation, which may have confounded neurologic assessment in a patient whose mechanism and signs indicated potential for significant traumatic brain injury. Traction and splintage of the injured extremity were likely partly facilitated by the onset of regional anesthesia.

FIB has theoretical advantages over femoral nerve block (FNB) by providing additional blockade of the obturator and lateral cutaneous nerves and reducing the risk of nerve injury, although there is no clear evidence of superiority in femoral shaft fractures. In this pediatric patient with very superficial anatomy and close proximity of structures, it is likely that the patient had an overlap FNB/FIB. Prehospital pediatric FIB has been described using a landmark approach, but sonographic guidance provides confirmation of correct tissue plane infiltration and reduces the risk of inadvertent vascular puncture. There is a lack of evidence to mandate aseptic technique in peripheral nerve blocks or single-shot regional blocks, although sterile gloves, aseptic skin cleaning solution, and a sterile probe cover are recommended. The maximum safe pediatric dose of ropivacaine is considered to be 2.5 to 3.0 mg/kg. Our patient received 2.7 mg/kg with excellent effect and no features of local anesthetic toxicity. The use of ultrasound-guided peripheral nerve blocks or regional blocks allows a lower dose to be given than the landmark technique because of the increased accuracy of target injection. In-plane needle placement is important to ensure correct needle location and drug delivery. In children, nerves have a smaller diameter with an incomplete myelin sheath compared with adults; hence, early onset of anesthetic block (motor and sensory) can occur even with lower concentrations of local anesthetic.

Current evidence indicates that FIB is safe and can be performed with high levels of success by a variety of different practitioners in the prehospital environment. Other sonographically guided regional anesthetic techniques are performed in our service, and the extension to pediatric patients is appropriate within a robust training and clinical governance framework.