USRA OF THE LOWER EXTREMITY

Transcription

1 USRA OF THE LOWER EXTREMITY Christian R. Falyar, CRNA, DNAP Department of Nurse Anesthesia Virginia Commonwealth University Disclosure Statement of Financial Interest I, Christian Falyar, DO NOT have a financial interest/arrangement or affiliation with one or more organizations that could be perceived as a real or apparent conflict of interest in the context of the subject of this presentation. Disclosure Statement of Financial Interest I, Christian Falyar, DO NOT have a financial interest/arrangement or affiliation with one or more organizations that could be perceived as a real or apparent conflict of interest in the context of the subject of this presentation. Disclosure Statement of Unapproved/Investigative Use I, Christian Falyar, DO NOT anticipate discussing the unapproved/investigative use of a commercial product/device during this activity or presentation.

2 Objectives State the indications for each lower extremity block Describe the ultrasound landmarks for each lower extremity block Review the ultrasound-guided needle insertion plane and local anesthetic requirements for each lower extremity block Discuss the side-effects and complications related to lower extremity blocks Lower Extremity Blocks Lumbar Plexus Femoral Adductor Canal Saphenous (thigh and ankle) Sacral Plexus Sciatic (gluteal level) Sciatic (popliteal level) Ankle Blocks Tibial Peroneal (Deep and Superficial) Sural Indications Regional anesthesia has many indications, including: Primary anesthetic Pain Management History of severe PONV or risk of MH Patient is too ill for general anesthesia Surgeon preference Contraindications In certain instances regional anesthesia should not be considered. Absolute contraindications include: Patient refusal Local infection at the site of the proposed block Active bleeding an anticoagulated patient Proven allergy to a local anesthetic

3 Contraindications Most contraindications to regional anesthesia are relative. The provider must determine the risk vs. benefit. Respiratory compromise Inability to cooperate/understand procedure An anesthetized patient (adult population) Bleeding diathesis secondary to an anticoogulant or genetic defect Bloodstream infection Preexisting peripheral neuropathy Pre-Procedure Prior to beginning any procedure: Verify the correct patient Obtain informed consent Verify the correct procedure Verify the correct extremity Gather all equipment Place the patient on oxygen Obtain baseline VS and monitor during the procedure Administer proper/adequate sedation Complications Regional anesthesia can result in complications such as: Local anesthetic toxicity Intra-arterial injection Respiratory compromise Parathesias and nerve damage Risks and benefits of regional anesthesia should always be discussed beforehand Local Anesthetics How much is enough? Most references recommend mls per block Some authors have demonstrated successful, complete blocks with less volume Amount and type of local anesthetic depends: Patient factors Timing of the procedure Procedure Purpose of the block

4 Local Anesthetics Drug Max Dose (mg/kg) Max Dose with Epi (mg/kg) Lidocaine*+ Drug 4.5mg/kg Max Dose (mg/kg) 7mg/kg Max Dose with Epi (mg/kg) Lidocaine* Mepivacaine*+ 4.5mg/kg 4mg/kg 7mg/kg 7mg/kg Mepivacaine* Bupivacaine* 2.5mg/kg 4mg/kg N/A 7mg/kg Bupivacaine* 2.5mg/kg 3.2mg/kg Ropivacaine* 5mg/kg N/A Ropivacaine* 3mg/kg 3.5mg/kg Procaine+ 12mg/kg 12mg/kg N/A N/A Chloroprocaine* 11mg/kg 11mg/kg 14mg/kg 14mg/kg Prilocaine* 8mg/kg 7mg/kg 8.5mg/kg 8.5mg/kg Tetracaine+ Tetracaine+ 3mg/kg 3mg/kg N/A N/A Femoral Block The femoral block targets the major branch of the lumbar plexus Provides anesthesia to the anterior thigh, knee and a small part of the lower leg The nerve is lateral to the femoral artery and deep to the fascia lata and iliaca, and superior to the iliopsoas muscle * - Nagelhout & Plaus, 5 th ed., pg Morgan & Mikhail, 5 th ed., pg. 272 Femoral Anatomy USRA Technique Fascia lata Fascia iliaca Pt. supine with slight external rotation of femur Transducer is placed at the inguinal crease, over the femoral pulse High-frequency linear array transducer Short-axis image, needle inserted in-plane Femoral nerve is a hyperechoic circle that lies lateral to the femoral artery 5 cm B bevel needle is used 20 to 30 cc s of local anesthetic injected

5 Pre-Procedure Scan USRA Technique Needle approach is lateral to medial Nerve stimulation can be used with ultrasound; patellar snap Major benefit of real-time imaging is visualizing needle movement and local anesthetic spread FI FL IPSM FN FA USRA Technique Femoral If more than one artery is visible, scan cephalad and identify a singular femoral artery Doppler can be used to verify femoral vessels Experience suggests that if the needle and the local anesthetic are placed below the fascia iliaca and lateral the artery, successful blocks occur despite the lack of twitches

6 Femoral Femoral Too low Just right Complications such as vascular puncture and local anesthetic injection are best avoided by observing the needle tip throughout the procedure Lymph nodes in the groin appear as nerves ; scanning proximal and distal will help distinguish the lymph node as they are not continuous and can be seen only at specific locations Femoral Adductor Canal The femoral nerve block (FNB) has been the gold-standard for pain relief following TKA Although effective for pain relief, it is associated with risk of falls Adductor canal block provides sensory nerve blockade with minimal motor involvement

7 Adductor Canal Anatomy USRA Technique Rectus Femoris Adductor Longus Adductor Canal Gracilis Vastus Medialis Sartorius Pt. supine, with slight external rotation of the operative leg High frequency linear array transducer placed midthigh in short axis orientation The superficial femoral artery and vein appear as hypoechoic circles bordered superiorly by the sartorius, laterally by the vastus medialis and medially by the adductor longus muscles Needle inserted using in-plane image Up to 20 ml of local anesthetic injected in the fascial plane bordering the superficial femoral artery Adductor Canal Adductor Canal Vastus Medialis Sartorius Adductor Longus Studies show consistent nerve identification and block success (100%), owing to the large hypoechoic superficial femoral artery and vein The vastus medialis will be blocked in some patients, however the clinical significance is not completely known

8 Saphenous (thigh) Saphenous Anatomy (thigh) Saphenous block at the thigh is used as an adjunct to a popliteal block for lower extremity surgery below the knee USRA Technique Pre-Procedure Scan Pt is supine with lower extremity slightly abducted Transducer placement is dependent on the method used to identify the nerve High frequency transducer Short-axis image, needle inserted in-plane Saphenous nerve is a hyperechoic circle that lies in the fascial plane between the sartorius and vastus medialis muscles 5 10cm needle is used 10cc s of local anesthetic injected

9 Pre-Procedure Scan Saphenous (thigh) saphenous nerve vastus medialis Saphenous (thigh) Saphenous (thigh) There are few complications associated with this block

10 Sciatic Sciatic Sciatic nerve arises from L4-5 and S1-3 Indicated for surgical procedures of the hip, thigh, posterior knee, lower leg and foot. Anatomical knowledge is paramount; locating needle with landmark or US may be difficult. Sciatic Popliteal Gluteal contraction indicates the needle must be advanced further Complications include: Intraneural injection Intravasuclar injection Targets the sciatic nerve slightly above the knee Provides anesthesia for procedures involving the foot and ankle In the popliteal fossa, the sciatic is bordered superiorly and medially by the semi-tendinosus and semi-membranosus muscles and superiorly and laterally by the biceps femoris muscle

11 Popliteal Anatomy Ultrasound Technique Prone, supine, or lateral position High frequency linear array transducer Transducer is placed in the popliteal crease Short-axis, in-plane or out-of-plane The sciatic nerve is superior to the popliteal artery and vein, then bifurcates in the tibial (larger), and peroneal (more lateral). 5 or 10 cm needle up to 30 cc s of local anesthetic injected incremental with negative aspiration Popliteal Pre-Procedure Scan Prone Supine

12 Popliteal Popliteal Ultrasound greatly reduces the traditional complications of intravascular and intra-neural injections When using nerve stimulation, dorsal or plantar flexion is acceptable Complications include: Intravascular injection Intraneural injection Popliteal Scan the proximal and distal to appreciate the anatomy The transducer may have to be angled toward to the foot to better image the nerves Circumferential spread around the nerve ensures a dense block Ankle Five nerves are blocked in the ankle Femoral saphenous Sciatic tibial sural deep peroneal superficial peroneal

13 Ankle Anatomy Ankle Ultrasound Technique Posterior Tibial Supine with foot elevated or extended past the end of the stretcher High frequency linear array transducer Short-axis, in-plane or out-of-plane Corresponding vascular structure identified first 5 cm B bevel needle 3-5 ml of local anesthetic injected following negative aspiration to achieve circumferential spread

14 Deep Peroneal Superficial Peroneal Sural Saphenous

15 Ankle Blocks Questions? Aggressive injections of large volumes of local anesthetic can cause hydrostatic damage to small nerves such as the deep peroneal nerve because it is enclosed in ligamentous spaces References Chan V., & Pollard B.; An Introductory Cirriculum for Ultrasound- Guided Regional Anesthesia; 2009, University of Toronto Press. Chan, Vincent; Ultrasound Imaging for Regional Anesthesia: A Practical Guide; 3rd Edition; 2010, Toronto Printing Company. Gray, Andrew; Atlas of Ultrasound-Guided Regional Anesthesia; 2007, Saunders/Elsevier. Hadzic, Admir; Textbook of Regional Anesthesia and Acute Pain Management; 2007, McGraw-Hill Medical. Morgan, G., & Mikhail, M.; Clinical Anesthesiology; 4 th Edition; 2006, McGraw-Hill Medical. Sites, B., & Spence, B.; Ultrasound Guidance in Regional Anesthesia: Techniques for Upper-Extremity and Lower-Extremity Nerve Blocks; 2008, McMahon Publishing. Zwiebel, W., & Pellerito, J.; Introduction to Vascular Ultrasonography; 5th Edition; 2005, Elsevier Saunders.