Neuraxial Anesthesia Flashcards

Question

Which needle reduces the occurence of post dural puncture headaches?

Answer 1

**Pencil Point Needles** (**Sprotte/Whitacre/**Pencan)

Designed to spread the dural fibers → help reduce the occurrence of post dural puncture headache
- Do not cut dura fibers (move dural fibers out of way)
Yields a distinct "pop"
- as the pencil point penetrates the ligamentum flavum & additional pop when going through dura matter
Offers increased "tip strength" to minimize bending or breakage
Precision-formed side hole enables directional flow of anesthetic and reduces the possibility

of straddling the dura

Tracks straight when advancing through ligaments toward the dura
Less likely to injure cauda equina
Does require more force

Answer 2

**Cutting Needle (Quincke/Pitkin)** (usually not used anymore) – in NM maybe. * Cutting needles actually cut, **so it cuts through the fibers** * Increased risk of PDPH due to increased trauma to the dura * CSF lost: Cutting \> Pencil point * Dural "pop" is *less likely to be appreciated due to the sharper tip -\> “less tactile”* * Introducer may not be necessary depending on patient size * **Bevel position important!** * **Bevel** **must be parallel to dural fibers → decreases incidence of PDPH** (less fibers cut) **_Bevel Position:_** * **Sitting:** **bevel** **facing left/right** * Ex: Dural fibers run longitudinally (head to coccyx) * **Lateral:** **bevel** **up/down** * Ex: longitudinal fibers are running horizontally * Less force * More likely to injure cauda equina

Answer 3

* Anatomic landmarks for the block are identified. * L2-3, L3-4, L4-5 interspace identified (Superior Iliac Crests is L4 Spinous Process) * A sterile field is established with prep solution is applied with **three basic sponges**, the solution is (applied starting from the injection site moving **outward** in a circular fashion. * In → out * A fenestrated drape is applied, and using a sterile gauze, wipe the iodine from the injection site to avoid initiation into the subarachnoid space. * make sure no cleaning solution gets into your actual SA space. * A skin wheal is raised with **2cc of 1% lidocaine** using a 25G needle to the selected space. * As you inject lidocaine, you use this needle to find your spinous processes. * The patient does not feel you hitting the bone, there is no pain with that. * Once you know where the spinous processes are and how they are angled, you get come out with local and get introducer. * A 17G introducer is passed through the skin wheal, angled slightly cephalad through the epidermis/dermis, sub Q, supraspinous ligament, interspinous ligament, stopping in the ligamentum flavum. Ensure bevel (of needle) is parallel to longitudinal fibers. * A 25G choice needle is inserted into the introducer, passing through the epidural space, dura, and arachnoid to the sub arachnoid space stopping when the presence of CSF is determined. * (**will feel a “pop” with a pencil point needle punches through dura mater**) * in very young pts you could even hear the pop. * Once you’re there you are in the SA space, there will be a little cap you can take off, once you take that off, you’ll see the CSF drop out. * CSF is aspirated and mixing lines are identified as a change in baricity and temperature as the local anesthetic and CSF mix in the syringe. * The dose is slowly injected, aspirating after instillation of half the amount of LA. * Aspirate again after some injecting. * After injection aspiration is making sure you’re not in the vasculature somewhere. * All needles are removed intact (at the same time) and the patient is positioned. * If you have a problem with good CSF flow and you know you’re in the right spot, try rotating your needle 90 degrees, you can do this up to 4 times, just keep going in the same direction. – increase in PDPHA with this rotation? No. If you use a pencil point needle, you’re probably going to be fine.

Answer 4

* Identify caudad edge of superior spinous process * Skin wheel 1 cm lateral and 1 cm caudad to that point (angle up) * Needle aimed 10-15 degrees medial and slightly cephalad * If lamina contacted needle **walked off** in a medial and cephalad direction * After CSF obtained same technique as midline – skipping supraspinous and interspinous ligaments, will go from skin/subq to ligamentum flavum

Answer 5

(Ones in **BOLD** are most important with SAB) * A number of factors affect the spread of the injected local anesthetic solution within the CSF and the ultimate level of the **block obtained**. Among these are: * **Baricity of the LA solution** * How heavy is the LA compared to CSF * **Position of the patient** * **Concentration and volume injected** * Level of injection (L2 vs L4) * Barbotage/Rate of injection * Very quickly → Will have a wider spread (higher block height) * Slowly – preferred, will help autonomics * Direction of needle & bevel * Bevel should be parallel to dura fibers * Pencil point- ok to have bevel perpendicular to dura * If bevel up → higher spread * If down → lower spread

Answer 6

1. **Surgical site** – spinal only reliably lasts up to 2 hrs, with decadron and vasopressors. * Decadron is effective in improving spinal anesthesia duration – no one knows why * *C/S- need to cover T4 nipple line* * *Cerclage only needs T10/T12* 2. Length of procedure * spinal only reliably lasts up to 2 hrs 3. Body size (height/weight) * *Morbidly obese individual – go slower on dosing, weight will compress that space, so if you dose (inject?) as normal you’ll get a big spread bc of the pressure of the body habitus.* * *Different heights need different amt spinal anesthetic* 4. Physiology

Answer 7

* **L2** = widest point * **5 mm** * Contains fat and blood vessels (Batson's plexus) * **Batson's plexus** – valveless veins, will aid systemic absorption * Fat – will absorb some of the lipophilic medicines * Closed space * Medication and catheter deposited into *potential* space * Epidural space is ***potential** space*- make exist when air/saline injected!

Answer 8

* **Continuous catheter technique** – **Tuohy needle** (slight curve with nice big open bevel at end) * Entire length = 10 cm * As you go through skin, subq, supra, intra, LIGAMENTUM flavum, this is where you stop with the needle, once its in there, stop. * **Just like with spinal needle, you want your Touhy bevel to be either left or right while sitting. Because if you go too far and give your patient a “wet tap,” the bevel angle will help you decrease risk of PDPH.** * **Loss of resistance technique** * Air or **saline** filled glass syringe * ~ once reached epidural space → fluid is released * ~ If tapping and no loss of resistance → not in epidural space * *research has shown air increases risk for PDPH. Saline has less risk*

Answer 9

* Pre-procedure considerations (same as SA) * Identify app level * Ex: Lumbar- Tuffiers line * At the desired spinous process, the Tuohy needle is advanced into skin, with the needle bevel parallel to longitudinal fibers: * Skin * Subcutaneous tissue * Supraspinous ligament * Interspinous ligament * Ligamentum flavum – there is often a “pop” as the needle pierces the Ligamentum flavum * Needle anchors there * (place glass syringe on bc next place is epidural space) * Epidural space * Need needle placement into ligamentum flavum * Ligamentum flavum depth from the skin is **4 cm** (**80% of patients between 3.5-6 cm)** * Tuohy needle 10 cm long (pay atten when around **3 cm** mark) * Feel anchoring (place glass syringe) * Thumb bounce on glass syringe * **Keep at least one hand at ALL times to anchor self to back** * **Advance little at a time and “tap” until resistance is lost** * 5-6 mm thick at midline in lumbar region * **_LOR technique_** - Steady pressure on plunger compress air bubble while advancing the needle – when epidural space entered resistance is gone and air (fluid) is easily injected * Ensure NO CSF after taking off syringe (if did→ wet tapped) → need to pull back needle and try again * **_Epidural Catheter Placement_** **(no CSF should be coming out)** * Note needle depth when **LOR noted** * Advance catheter after LOR cm amount: * **Normal Pts**: **2-3 cm** advance * Ex: if LOR at 5 cm → advance catheter to 8 cm * **PARTURIENTS:** **4-6 cm** advance * Ex: if LOR at 5 cm → 9-11 cm of cath in pts back * Remove Tuohy needle WITHOUT removing catheter . DO NOT PULL CATHETER BACK WITH TUOHY NEEDLE IN PATIENT- can shear off catheter * Instead “push-pull” action * Push catheter as you remove the Tuohy needle * Ensure tip of catheter remains sterile

Answer 10

* **Always aspirate!!! and give a test dose prior to injection/use incremental dosing-** *note baseline HR and BP* * aspirate before injecting LA. (before test dose or when increasing dose) * Only inject a small amount at a time * ~ 5 mL max, then aspirate again and inject another fine. **Traditional test dose: 3ml** * **Lidocaine 1.5% w epinephrine** * Epinephrine 1:200,000 dilution * 45 mg lidocaine and 15 mcg epinephrine * Helps detect → **accidental intravascular & subarachnoid injection** 1. **Intravascular injection**: HR increase w/in 30 sec (~15-20 points) 2. **Subarachnoid injection**: (“wet-tap” block) * Ask pt if they have numbness or tingling * Epidural block normally takes a few minutes * If saying lost sensory and motor quickly w/in 1 min of test dose → in subarachnoid space * If it takes 5 minutes for that onset of can’t feel legs – probably epidural. * **_You should NOT be expecting a quick acting epidural_** Prior to test dose: note HR and BP!! * Always give test does with epidural, test dose has 2 points * **After you give a test dose you really should wait 5 minutes before epidural.**

Answer 11

* **Volume and Concentration of LA (helps det. Level of spread)** * **Large volume of a dilute solution** * Decreased sensory and motor blockade with wide segmental spread. * **The quality and extent of the epidural block is dependent upon volume and concentration of the LA** * For induction of epidural blockade: * **1.25 - 1.6 ml of LA** **per segment** **you need.** * Ex: epidural placement at L3-4 interspace and need T4 level sensory blockade * Count up to T4 level and give 1.25-1.6 ml PER segment * *Look at Bowman lecture examples for doses!*

Answer 12

1. Hypotension * Tx: * 1. Prevention → fluid * 2. Vasopressors or vagolitic drugs if blocked at T1-4 level 2. Bradycardia 3. Sudden cardiac arrest 4. N/V * From unopposed GI PSNS activity * But most likely caused by HYPOTN → tx 5. Unintentional Intravascular Injections * Epidural * use test dosing * note VS BEFORE/AFTER injection of test * KNOW: * s/s of LA toxicity * numbness lips, ears ringing, coma * tx of LA toxicity (BOWMAN LECTURE) 6. Unintentional Intrathecal Injection * TEST DOSE important → identify quick sensory blockade (= intrathecal) 7. Catheter shearing * Do not remove catheter within Tuohy needle * Catheter shearing as you try and advance it, the needle can shear it off in the body. 8. Post-dural Puncture Headache → wet tap, may happen. 9. High Blockade * Prepare for AW management * Symptomatic support (vasopressors/vagolytic tx) 10. Inadequate Blockade * Ex: one side might be better blocked than the other, when this happens have the pt lie on the side that is not well blocked. Should help some. GRAVITY * If completely inadequate, remove block and try again. 11. Neurologic Complications 12. Backache 13. Infections – septic meningitis 14. Urinary Retention 15. Epidural hematoma

Answer 13

Incidence: 1 – 4 % * **Increased incidence:** * Younger female patients * Larger needle size * Pregnancy * Air for LOR (instead of saline) * Cutting tipped needles perpendicular to meninges * Multiple puncture attempts **Causes:** * CSF leaking out of subarachnoid space * As CSF leaks → decrease intracranial pressure with compensatory cerebral vasodilatation → brainstem sags which stretches meninges and pulls on the tentorium * **S/S:** * Frontal to occipital area (Fronto-occipital) * Postural * Sit up/stand → PAIN * Lay down → immediate relief * Occurs **within 1 day to 1 wk of spinal/epidural anesthesia** **Treatment** * Bedrest, hydration, oral analgesics (NSAIDs), caffeine, abdominal binder, epidural saline injection * **Epidural Blood Patch**

Answer 14

* Younger female patients * Larger needle size * Pregnancy * Air for LOR (instead of saline) * Cutting tipped needles perpendicular to meninges * Multiple puncture attempts

Answer 15

* **_Primary cause:_** **coagulation defect** * Plt req_:_ \> 100,000 * Check bleeding time * Presents with numbness or lower extremity weakness *greater than expected from spinal anesthesia* * Consult neurosurgery immediately if a hematoma is suspected * 6-8 hrs before permanent injury * Greater than 8 hours makes the odds of decompression less successful

Answer 16

* LMWH – Prophylactic dosing * hold 10-12 hours _pre-placement of epidural_ * hold 10-12 hours _post surgical procedure (apex says 6-8)_ * LMWH – Therapeutic dosing: * Hold 24 hrs before block * Hold 24 hours after block * Heparin * Can be given 1-2 hours post SAB/epidural (dvt prevention) * Hold 2-4 before block placement * Warfarin * Before block hold 5 days

Neuraxial Anesthesia Flashcards

(40 cards)