Ultrasound Guided Blockade of the Lumbar Plexus - the Supra Sacral Parallel Shift

Study Overview
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Brief Summary
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Anesthesia for hip surgery can be performed with ultrasound guided blockade of the mesh of nerves (the lumbar plexus) supplying the hip region from the lumbar spinal nerves. This is a relevant technique in patients with severe cardiac comorbidity. The technique is a safer alternative compared to general or spinal anesthesia in these fragile patients. The most recognized technique with ultrasound guidance (Karmakars technique) is technically demanding and based on injection of local anesthetic relatively close to the exit of the spinal nerves from the spine. The risk is spread of local anesthetic to the spinal canal prompting a risk of low blood pressure. This may be fatal in high risk patients. The investigators have developed a simple technique based on injection away from the spinal canal. The investigators expect minimal risk of spread of local anesthetic to the spinal canal with this technique. This randomized, double blinded trial compares the new technique to the established technique of ultrasound guided blockade of the lumbar plexus. The hypothesis is that the new technique has a higher success rate with reduced effect on blood pressure for ultrasound guided lumbar plexus block compared to the established technique.

Official Title
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The Supra Sacral Parallel Shift (SSPS) - Ultrasound Guided Blockade of the Lumbar Plexus

Conditions
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Hip Fracture

Intervention / Treatment
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* Procedure: Lumbar plexus block using LUT technique
* Procedure: Lumbar plexus block using SSPS technique


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: written informed consent ASA I (American Society of Anesthesiologists physical status classification) Exclusion Criteria: volunteers who are not able to cooperate volunteers who do not understand and speak danish daily use of analgesics allergy to local analgesics or contrast agents abuse of medicine or alcohol volunteers with technical impediments of the planned interventions

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Lumbar ultrasound trident (LUT)<br>Lumbar plexus block using LUT technique | Procedure: Lumbar plexus block using LUT technique<br>* Lumbar plexus block guided by ultrasound and nerve stimulation with the patient in the lateral position and the probe in the parasagittal plane inserting the block needle between the transverse processes of L3 and L4 until an appropriate neuromuscular response is produced.<br>|
| Experimental: Supra Sacral Parallel Shift (SSPS)<br>Lumbar plexus block using SSPS technique | Procedure: Lumbar plexus block using SSPS technique<br>* Lumbar plexus block guided by ultrasound and loss of resistance (LOR) with the patient in the lateral position and the probe in the parasagittal plane inserting the block needle between the transverse process of L5 and the sacral bone until an appropriate LOR is produced.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Success of complete sensory blockade of dermatomes L2, L3, L4, L5, S1 |  | 30 minutes after injection of local anesthetic | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma lidocaine level (mcg/mL) | Chromatography analysis | 0, 5, 10, 20, 40, 60, and 90 minutes after injection of local anesthetic | 
| Block performance time |  | From start of probe on the skin until injection of local anesthetic is completed | 
| Patient satisfaction |  | Immediately after completion of injection of local anesthetic | 
| Mean arterial blood pressure (MAP) | Absolute measure and relative change from pre-block measure | 5 minutes after completion of injection of local anesthetic | 
| Cost-effectiveness | Estimated as incremental cost-effectiveness ratio | Block performance time period | 
| Sensory blockade of each dermatome L1, L2, L3, L4, L5, S1, S2, and S3 (cold, warmth, touch, pain) |  | 30 minutes after completed injection of local anesthetic | 
| Sensory blockade of the femoral nerve (cold, warmth, touch, pain) |  | 30 minutes after completion of injection of local anesthetic | 
| Motor blockade of the femoral nerve |  | 40 minutes after completion of injection of the local anesthetic | 
| Motor blockade of the obturator nerve |  | 40 minutes after completion of injection of the local anesthetic | 
| Perineural spread of local anesthetic (with contrast) estimated with MRI |  | 60 minutes after completion of injection of local anesthetic |