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Upper Ext Blocks
Upper Extremity Nerve Blocks
Question | Answer |
---|---|
Spread of block is r/t? | Volume...more volume better spread |
Which will be blocked 1st in a brachial plexus block, proximal or distal? | Proximal areas will be blocked first as they are on the outer surface of the nerve sheath |
Brachial plexus anatomy | Roots, trunks, divisions, cords, branches |
How do you test a brachial plexus block | Push, Pull, Pinch, Pinch |
What does the "push" test for in a brachial plexus block | Push tests the radial nerve which innervates the triceps muscle |
What does "pull" test for in a brachial plexus block? | Pull tests the musculocutaneous nerve which innervates the biceps muscle. |
What does "pinch, pinch" test for in a brachial plexus block. | One pinch to the pinky test the ulnar nerve and one pinch to the index finger tests the medial nerve. |
The ________ nerve supplies sensation to the majority of the back of the hand/arm? | Radial nerve. |
A major risk of an interscalene block? | There is a high risk for phrenic nerve block (unilateral). This is usually of little consequence in healthy patients but can lead to respiratory distress in patients who already have a comprimised resp status. |
What type of surgeries is an interscaline block good for? | Surgeries of the upper arm and shoulder. This block often misses the ulnar nerve and is thus not good for surgeris of the lower arm. |
Duration of a interscalene block. | 6-8 hours of surgical anesthesia with up to 24 hours post-op pain relief. |
What level of the brachial plexus does an interscalene block work on? | The level of the trunks (superior, inferior, and middle) |
The cricoid cartilage corresponds to what vertebral level? For what brachial plexus block is this used as a landmark. | The cricoid cartilage is at the level of C6, which serves as a guide when preforming an interscalene block. |
Two "NEVERS" for an interscalene block | Never direct the needle cephalad and never insert the needle more than 2.5cm (even in obese patients) as this is a superficial block |
Needle insertion site for interscalene block. | The needle is inserted into the interscalene groove at the level of C6 (cricoid cartilage). 22g needle is inserted in a slightly caudal and posterior direction and may be redireced with in the plane of the C6 vertebrae until paresthesia is elicited. |
Potential complications of interscalene block. | IV injection, neuraxial block, phrenic nerve block(50%++), PNA, infection, hematoma, paresthesia, Horner's syndrome (30-40%), recurrent laryngeal nerve block (30-50%), total spinal anesthesia, nerve injury. |
How do you prevent total spinal anesthesia during a interscalene block? | This can be prevented by monitoring for muscular response to current intensity less than 0.2mA. If this occurs, pull needls back slightly until the same response requires more than 0.2mA. |
Horner's Syndrome....what brachial plexus block can cause this, what are the symptoms, what is the incidence, and what structure is being blocked to cause this. | This can happen with a interscalene block as result of block spread to the stelate ganglion. Will result in ptosis, miosis, anhydrosis, increased skin temp, nasal congestion. This occurs less commonly with low interscalene block. |
Needle size for interscalene block | 22g short needle (never insert greater than 2.5 cm) |
Nerve usually missed by interscalene block | Ulnar nerve |
Interscalene block durations | 6-8 hours of surgical anesthesia and up to 24 hours of postop analgesia |
Goal of nerve stim during interscalene block | Stim of brachial plexus with 0.2-0.4mAmps. May see deltoid, pectoralis major, triceps, biceps muscle twitching |
LA injection for interscalene block | When muscle twitches are elicited at less than 0.5mAmps, inject 0.5ml of test dose of La...if no pain inject remaining LA in 5ml increments. Total volume of 35-40ml. |
How long for interscalene block to set up? | 30-40min of soak time |
Wh is a supraclavicular block "better" than an interscalene block? | Supraclavicular block, works at the level of the divisions, the nerve bundle is more tightly together at this level than at the level of the trunks for and interscalene block. |
Complications of supraclavicular block | Pneumothorax 1-6%, infxn, hematoma |
Nerve often missed by ax block that needs to be blocked seperately | Musculocutaneous nerve will not be blocked by an axillary block and must be blocked seperately. |
How is a musculocutaneous block performed. | By injecting 5cc of LA into the corachobracialis muscle |
Volume of LA for ax block | 34-40ml |
Three ways to preform an ax block | Paresthesia, transarterial, nerve stimulator |
Intercostal block contraindications | When pneumo would be disasterous, local infection, hemostatic deficiencies, lack of any short term plan to wean from vent, lack of resucitation equipment, lack of expertise |
Anatomy of intercostal block | Ride rib down to its inferior border to block nerve which lies on inferior border, just below the artery, which is just below the vein (Vein, Artery, Nerve) |
Needle size for intercostal block | 25g, short |
Volume of LA for intercostal nerve block | 3-5 ml of LA at eachh level |
DOA of intercostal nerve block and type of LA | Usually 12 hours +/- 6 hours with bupivicaine 0.25-0.5%, Ropivicaine 0.5-0.75%, lidocaine with epi 1-2%. Adding epi to ropivicaine or bupivicaine does not significantly prolong the block. |
Digital nerve block of hand | Inject 1-2ml of LA in medial & lateral aspect of digit with a 25g 1 1/2 in needle. Easier to do with hand pronated. Inject and form wheal on insertion and then direct needle anterioraly until phalanx is encoutered or ventral skin begins to tent. |
Complications of digital nerve block | GANGREEN-No vasoconstrictors, limit volume to 2ml. NERVE INJURY-awake pt, no inject if pt c/o pain or there is increased pressure when injecting. INFXN. HEMATOMA-avoid multiple needle insertions, use 25g needle. VASCULAR PUNCTURE-Intermittent aspiration. |
Ulnar nerve block at the wrist | Lies lateral to the flexor carpi ulnaris tendon & medial to the ulnar artery. Small gauge short-bevel needle is inserted perpindicular to wrist- causing paresthesia, inject 3-5ml of LA. If no paresth. inject in fan like fashion between two landmarks. |
Median Nerve Block at the wrist | Lies deep and between palmaris longus t & flexor carpi radialas t. Small gauge short needle inserted between two tendons & 3-5ml of LA injected...if no paresthesia inject in a fan like manner between two tendons. |
Radial Nerve Block at the wrist | Radial nerve at this level has already divided into many branches and requires a field block of radial aspect of wrist. It may require 5-6ml of LA and is not often used. |
Disadvantages of intercostal block | Requires supplemental systemic analgesia, requires technical expertise, risk of pneumo, LA toxicity with multiple levels of blockade |
Advantages of intercostal block | Superior analgesia, opioid sparing, improved pulm mechanics, reduced CNS depression, Avoid urinary retention |
Ax block nerve stimulator settings | Start at 1-2mAmps and drop to 0.5mAmps |
Ax block continuous catheter infusion | 0.25% bupivicaine or 0.2% ropivicaine run at 4-10ml/hr |