Femoral Nerve Block With Bupivacaine and Adjuvant Dexamethasone in Patients With Hip Fracture

Analgesic Duration af a Preoperative Single-shot Femoral Nerve Block With Bupivacaine and Adjuvant Dexamethasone in Patients With Hip Fracture

Prolongation of the analgesic effect of a femoral nerve block from the present 15 hours to 24 hours in patients with hip fracture would have a major impact in order to provide better preoperative analgesia for this group.

In other trials concerning other nerves then the femoral nerve the addition of Dexamethasone to the local anesthetics doubled the analgesic duration. No studies has investigated the effect of the addition of Dexamethasone to the femoral nerve block in patients with hip fracture.

The aim of our study is to investigate if more patients with hip fracture experience lasting preoperative analgesia until the time of operation or 20 hours after a femoral nerve block with the addition of Dexamethasone compared to the same nerve block done without Dexamethasone.

Patients with hip fractures are most often old, have multiple comorbidities and suffer severe pain.

Femoral nerve block as a means of preoperative analgesia for these patients has proven effective in multiple trials for the majority of the patients. Still some issues remains to be investigated in order to optimize the preoperative analgesia for this group.

One of the issues that reduces the feasibility of the femoral nerve block is the relatively shorter analgesic duration of the nerve block compared to the often longer time from the hospital admission to the actual operation. From the literature and our own experience the mean analgesic duration of a femoral nerve block approximates 15 hours.

Many studies have shown a prolonged analgesic duration of different nerve blocks when Dexamethasone was added to the local anesthetics. Some studies show a 100 percent increase in duration.

To our knowledge no studies have been published regarding prolongation of the analgesic effect of the femoral nerve block with Dexamethasone, and also none regarding the group of patients with hip fracture.

The clinical impact of a femoral nerve block with an analgesic duration of 20 hours compared to the present 15 hours would be less patients waking up in wards during the night time with pain and a terminated femoral nerve block.

The purpose of this study is to investigate if more patients with hip fracture experience a lasting preoperative analgesic duration of at least 20 hours or until the time of operation after a femoral nerve block with Bupivacaine with adrenaline and the addition of Dexamethasone compared to the same nerve block done with only Bupivacaine with adrenaline.

Inclusion Criteria:

• Clinical suspicion of hip fracture
• Age ≥ 55 years
• Mentally capable of comprehending and using verbal pain score
• Mentally capable of differentiating between pain from the fractured hip and pain from other locations
• Mentally capable of understanding the given information
• Arrival in the emergency room at times when one of the doctors who do the nerve blocks for this investigation are on call
• Verbal pain score (0-10) ≥ 7 with passive leg raise of the fractured leg at the time of inclusion
• Patients informed consent

Exclusion Criteria:

• Hip fracture not confirmed by x-ray
• Weight < 40 kg
• Verbal pain score > 3, 30 minutes after the nerve block
• Verbal pain score > 5 with passive leg raise, 30 minutes after the nerve block
• Patient has previously been included in this trial
• Ongoing pre traumatic treatment with parenteral or intravenous adrenocortical hormone
• Verbal pain score > 3 from other locations than the fractured hip
• If the patient wishes to be excluded
• Allergy to local anesthetics or adrenocortical hormone
• Visible infection in the area of the point of needle injection
• Acute inability to comprehend and use verbal pain score