Anesthesia for Orthopedic Surgery Flashcards

Question

Shoulder arthroplasty indication, duration and position?

Answer 1

* Indications: Arthritis, DJD * Durations: pot. long procedures up to 3 hrs. * *May not be comfortable for awake patient* * Position: Sitting or lateral position (think complications)

Answer 2

Technique: * ETT, GA w/LMA- * Interscalene or Supraclavicular (CONSIDER REGIONAL TOO) * **NO Tourniquet** Considerations: * Significant blood loss (EBL ~1-1.5 L) * Need 2 or more large IV’s, CBC preop, at least T&S * Hypotensive anesthetic technique * Set MAP/SBP goal to decrease BL * VA/Propofol, vasodilator, etc * **DO NOT DO ON PTS** W/ carotid stenosis, stroke, poorly controlled HTN pt→ cant autoreg CPP * Tranexamic acid (TXA) * Embolic syndromes * Prone to DVT/PE

Answer 3

* Frequently reassess eyes, ears, head/neck alignment, legs, hips * Axillary chest roll (brachial plexus protection) * BP cuff pressure on lower arm- BP may reflect it is higher than actual pressure (consider placing on leg)

Answer 4

* Gravity → affects how well lung will perfuse/ventilate * *young/healthy tend to tolerate fine* * Unanesthetized: * V/Q Non-dependent \<\< Dependent * Anesthetized: * Nondependent: V \> Q (perfusion does not change from awake) * Dependent: V \< Q (hard to ventilate dep. Lung)

Answer 5

Complications * Potential for nerve injuries * BP #1 * Cervical spine injury (avoid head dislodgement) * Consistently check * Excess flexion of neck * (may obstruct internal jugular vein—venous engorgement) * Excess extension of neck may impair CBF—cerebral ischemia * Macroglossia- MOA?? * Last hrs after sx (bite blocks may put pressure and cause swelling) * Eye injury * avoid deliberate hypotensive technique * avoid pressure on eyes/ears **Hemodynamic challenges** * Decrease BP * Venous pooling * Decrease CO * ¯Decrease Intrathoracic blood volume * Correctly monitoring BP important (*previous lectures says 1 cm rise = 0.75 mmHg decrease)*

Answer 6

* 2-3 fingers underneath chin strap * No extend/flex * Head turned slightly away from sx site * Eyes protected

Answer 7

* Performed under both regional and general * *choice also depends on skill of surgeon* * Regional: studies show decrease BL during total hip * (And decrease mortality, DVT, LOS, cost) * Goal: provide post-operative analgesia * Rapid post-operative rehabilitation- *mandatory* * **Reduce post-operative morbidity and mortality (DVT/PE)** * Total Hip 42-57% (DVT)/0.9-28% (PE) * Total knee 41-85% (DVT)/1.5-10% (PE) * Hip fracture 46-60% (DVT)/3-11% (PE) * Use of LMWH (ex. Lovenox) and Coumadin

Answer 8

* Technique: SPINAL * Large incision-iliac crest to mid-thigh * Muscle relaxation needed to access joint (spinal ideal) * Femoral head is dislocated from acetabulum * Arthritic femoral head and portion of neck excised * Acetabulum & femoral canal reamed to accept cemented (methyl methacrylate) metal/plastic prosthesis * Cup, ball and stem replace femur head * **Blood loss 500-1000 ml (~1-1.5 L)** * Hgb threshold for replacement \< 10 conservative or \< 8g/dL studies show no difference in outcomes * CV pts → higher threshold for transfusion

Answer 9

* D/C anti-inflammatory meds at \> 1 week prior * HERBALS ~ 2 weeks d/c * Joint degeneration: AW assessment! * Assess flexion, extension, cervical, TMJ * T&C/autologous/cell-saver * Optimize pt before sx

Answer 10

* Elderly w/ underlying disease * Cardiac function difficult to assess (A-line, CVP?) * Careful fluid management * Balances technique (crystalloids/colloids/blood tx trigger) * Hypoxia and pulmonary edema increase * Fat or bone marrow emboli → anytime working in long bones

Answer 11

* Anterior approach → spine position * **Lateral decubitus (HIP)** * V/Q mismatch * Neurovascular complications * Head & shoulders in neutral position * Dependent arm abducted on padded arm rest → ensure IV working * Axillary artery * Place ax. roll * Femoral nerve injury- *surgery or positioning related* * Careful with excessive hypotension.

Answer 12

**(can still do regional too)** * Need muscle relaxation * Definitive pain control plan throughout surgery and post-operative period → get regional before start * *Consider PCA or combined regional techniques for postop* * Patient may be difficult to position – d/t presenting underlying condition * ASA status and co-existing disease may be an issue. * Maintain normothermia

Answer 13

* **Neuraxial anesthesia** * Spinal * Spinal/epidural combo * **Lumbar** plexus block or psoas compartment block * **Femoral nerve block** * quadriceps weakness increases postoperative falls * Adequate IV hydration to avoid decreased BP w sympathetic block (Two 14-16g IVs ideal) * Neuraxial * SAB (hypobaric or isobaric) or Epidural- lumbar spine unaffected w rheumatoid * 250-500 ml fluid bolus to offset sympathetic block * Considerations * Patient may be difficult to position → degenerative dx hard to get spinal (general as backup) * Case length may predispose patient to discomfort * Regional provides post-op pain control * Airway control in lateral

Answer 14

* Deliberate hypotension (Diltiazem, nitroprusside, ntg, beta blockers) or regional anesthesia recommended to decrease * HIPS- no tourniquet = BL * (neuraxial anesth will decrease BL- LA will cause peripheral vasodilation will decrease BP → decrease BL) * Autologous donation * Cell saver * Tranexamic acid (TXA)\*

Answer 15

* **Surgeons-“cocktail” –** may contain a LA, epi (vasocontriction), NSAIDs, opioid, a corticosteroid, and/or an antibiotic into the periarticular space

Answer 16

* Morbidity: * DVT \>50% without prophylaxis and 10-20% with anticoagulant * Use compression device * Traction or abduction wedge postop → prevent adduction (increases limitations postop)

Answer 17

* decrease BL 29-54% * Antifibrinolytic * MOA: Inhibits conversion of plasminogen to plasmin * Synthetic derivative of lysine by blocking lysine binding sites, inhibits conversion to plasminogen to plasmin, reducing fibrin degeneration and preserving/stabilizing fibrin mesh (produced by 2ndary hemostasis) * HELPS CLOT, PREVENTS BREAKDOWN OF CLOTS * **Complications:** * PE/DVT\* * NO kidney/liver dx * Dosing: depend on fibrinolytic response according to the type of surgery * 10 mg/kg loading dose prior to incision * Followed by 1 mg/kg/hr infusion (app dosing wont cause PE/DVT) * Optimal dosing is probably procedure-specific * Low protein binding (3%) * 5% metabolized by liver * 95% excreted unchanged by kidneys * Elimination ½ life @ 2 hrs

Answer 18

MMA (bone cement) * Binds prosthetic with bone. * Composition: (2) * PEARLS- small particles of prepolymerized MMA (white powder) * Liquid monomer * Cement mixing causes exothermic reaction; expands causing pressure against bone surface * 2 are mixed → catalyst causes polymerization process → hardens → pearls sealed w/in monomer * Grout/filling of empty spaces (no adhesive properties) → tight hold of implant/bone surface * Intramedullary hypertension pushes fat, air, and marrow into the femoral venous channels. * Concerns: * Vapors harmful * Irritant to skin * Reproductive system issues → no preg providers

Answer 19

Physiologic changes for 2-17% w/ methyl methacrylate (MMA)→circulating monomers. more recent theories say it's an embolus of some sort * SEE W/TIME OF INJECTION: * decrease SVR, BP, HR, hypoxia, cardiac arrhythmias * increase PVR * loss consciousness (under neuraxial tech) * cardiac arrest * **1^st SIGN** * GA = decrease ETCO2 * Regional = dyspnea/altered sensorium * Tx: turn off N2O, 100% O2/Aggressive fluids/ Correct hypotension w/ alpha agonists * Prior to cement: * BP should be optimized, turn to 100% O2, have full bags of fluids on pressure bags, inotropes, fluid bolus * Document cement timing on record

Answer 20

* Profound hypotension immediately after insertion of cemented femoral prostheses has resulted in cardiac arrest and death * Uncommon during elective primary total-hip replacement but **not** uncommon in certain **high-risk groups.** * **Admin → Emboli and debride can travel to lung/heart → causes RV heart dysf → CV collapse** * Hypotension is related in some way to the use of cement. Possible explanations are: * Caused by direct vasodilation or cardiac depression from methylmethacrylate. * Caused by the forced entry of air, fat, or bone marrow into the venous system, with resultant pulmonary emboli.

Answer 21

* Hypoxia: immediately after insertion of a cemented prosthesis and for up to **5 days** into the postoperative period. * **In the event of hypoxemia:** * FIO2 100% * Rule out: * atelectasis of the dependent lung, hypoventilation, fluid overload. * Grade 1: moderate hypoxia (SpO2 \< 98-4%, SBP decrease \> 20%) * Grade 2: severe hypoxia (SpO2 \< 88%, SBP decrease \> 40%) * Grade 3: CV collapse (CPR) * May be a result of the embolic effects of shaft cement or fat embolism caused by expansion. * **Postoperative management:** * Nasal oxygen * Pulse oximetry for several days * Appropriate fluid management/ diuresis.

Answer 22

* Preop assessment/ evaluation- *identify high risk patients* * ASA 3 & 4 * Older Age * Impaired CV/pulm (pulmHTN) * Boney metastasis * Anesthetic technique * maintain normovolemia * high inspired concentrations of FiO2 * **reduce MAC if using volatile agent → not as much CV compromise** * Consider fluid bolus prior to implantation * Invasive hemodynamic monitoring * Intraoperative cardiac output monitoring * Vasopressors & positive inotropic agents on standby * Surgeons: know this is possibility → will announce * Lavage intramedullary canal of femoral shaft * Maintain hemostasis * Non-cemented prostheses → pts get readmitted.. * Drill vent hole in distal femoral shaft

Answer 23

* **72 hrs post-op long bone fracture** * **Brain**: * Confusion * **Skin**: * Petechial rash (chest) * **Pulm: 1^st sign (75% pts)** * decrease arterial O2 * Dyspnea * Diffuse alveolar infiltrates * Pulm edema * Sudden decrease ETCO * Progress to resp failure (10%) * EKG changes / tachycardia

Answer 24

* Without prophylaxis → DVT develops in 40-80% of orthopedic patients * Risk factors: * high BMI * COPD * anemia * presence of preop DVT Prevention? * d/c procoagulant medication * Autologous blood donation * Hypotensive anesthesia * Regional anesthesia * IV heparin during surgery * Aspiration of intramedullary contents * Pneumatic compression * Knee-high elastic stockings * Early mobilization * Chemoprophylaxis

Answer 25

* Common pts: blood supply high → need to fix fast * ~ 80 yo average (low mobility) * women (low bone density) * multiple medical problems * In-hospital morbidity i~3%, and at 1 year, 20% have died. * Present with Dementia * Mortality → ASA status and AGE influence

Answer 26

* Fracture table- femur fracture * Pad perineal post * Arm ipsilateral to fx hip on arm board or sling-avoid Xray obstruction * Supine → controlled positioning of extremities * Allows for XRAY access * Perineal post must be padded before patient on table → predundel (?) nerve injuries

Answer 27

* Reaming/implant. * EBL can be high * Regional v. GA (dep pts, sx, etc) * Regional anesthesia (spinal or epidural) -reduce the perioperative risk of death, pulmonary complications, and deep venous thrombosis (DVT) by 30% to 50%. * Most common cause of intraop death → **MI & PE.** * Post op complications like pneumonia also contribute greatly to mortality.

Answer 28

* Diagnose and treat intra-articular problems (elective procedures, pts should be optimized) * Ex: torn meniscus/ACL, loose bodies, arthritis and infections. * Position: * Supine * foot of OR table lowered for access * Multiple entry points at knee entered via scope. * Separate open incisions may be made for meniscus repairs. * Debridement and meniscectomy performed in conjunction with arthroscopy * Irrigating fluid (3-5L bags) used → caution w/ CHF (pulm edema) * Fluid gets absorbed systemically

Answer 29

* Minimal EBL * Tourniquet sometimes used * Ambulatory procedure * Intra-op antibiotics * Can consider General or Regional * Advantages/Disadvantages of each → might block motor fx and they need to get up to mobilize * OR turnover/pt. recovery/optimal operating conditions/minimal side effects

Answer 30

* Femur patella and tibia are exposed * Cartilage and bone excised with saw * New components cemented into place * **Tourniquet used** * ~ 2 units blood loss if no tourniquet * Positioning Supine

Answer 31

* Pts have: * Severe RA, Degenerative OA, Obesity * Other significant co-morbidities that compound the difficulties of the operation. * Procedure: 1-3 hrs * Postop pain * Regional great option (Fem/sciatic block) → reduces BL, DVT, mortality, N/V, etc * Morbidity: * DVT prophylaxis * Risk of post-op dislocation \<35% * PE 1-7%

Answer 32

* **Regional**-neuraxial and peripheral blocks * (femoral nerve block, saphenous/adductor canal block, lumbar plexus block, sciatic n.b w/ femoral n.b., selective tibial nb w/ FNB, obturator nb w/ FNB * Tourniquet * inflated ~100mmHg above pt. SBP for 1-3 hours- * must block all 4 nerves: femoral, lateral femoral cutaneous, obturator, sciatic * **Spinal**: hyperbaric (high sensory-more than needed) or isobaric\* or hypobaric * **Epidural**- continuous catheter tech → postop * **PNB**: Femoral 3 in one or psoas- usually combined w a spinal or general for post-op pain relief 12-24 hours

Answer 33

* Supine or prone (for calcaneous) * Regional v. GA or local block * Selection of regional technique dependent upon: use of calf or thigh tourniquet/degree weight bearing and ambulation post/ and need postop analgesia * **Thigh tourniquet \>15-20 min requires GA or neuraxial** * If no thigh tourniquet- combined sciatic(blocked in popliteal fossa) and femoral nerve (blocked on medial aspect of leg just below knee) blocks sufficient * Sedation * Consider patient related morbidities * Diabetes- PVD * HTN * PVD

Answer 34

* Coexisting Disease * Diabetes * Peripheral Vascular Disease * Cardiovascular disease * Surgical Procedure * Leg completely excised at distal one third of the femur * Supine position * **Tourniquet used**- no major blood loss

Answer 35

* Anesthetic Management * Regional- Epidural + adjuncts (Clonidine 30mcg/hr) * General- multimodal: **Ketamine infusion (0.01-0.03mg/kg/min)/opioids** * Post-op * Epidural- Bupivacaine 0.125-0.25% + fentanyl 2mcg/ml * Psychological considerations

Answer 36

* AKA: distal 1/3 portion of femur removed, stump fashioned with flap for prosthetic * Traumatic AKA: stump not fashioned. Return to OR every 1-3 days * BKA: mid leg portion removed

Answer 37

* **Gangrene**, **septic**, chronic disease, trauma *(RA good idea?--\> no)* * Avoid w/ systemic infection (sepsis, gangrenous), trauma → just do GA * 250cc EBL (using turniquets) * Mortality:10-20% * Morbidity: phantom limb 85-95%, wound infection \<15%, pneumonia 10-15%, MI 7-10%, emboli 6-10%, CVA 5-10%

Answer 38

* Femoral, lateral cutaneous, obturator nerves * Sx: femoral shaft/neck fractures, knee (ant thigh) → not adequate alone for sx of LE bc contributing innervation of sciatic nerve * *not used often, difficult technique and frequent failure* * Motor & Sensory- Hip/Anterior Thigh/Knee * Sensory- medial upper and lower leg/ankle * Positioning: * LDP w/ slightly forward tilt * Nerve stimulator (put sx side over dependent leg → see response) * Landmarks: * Midline of spinous processes * Iliac crest * Needle insertion- 4 cm lateral to midline

Answer 39

* Nerve roots L4-5 + S1-3 (larges nerve in body) * Lumbosacral trunk- anastomosis of last 2 lumbar nerves w/ anterior branch of 1^st sacral nerve * Exits the pelvis at greater sciatic foramen, below piriformis muscle, descends b/t greater trochanter of femur and ischial tuberosity * Travels under gluteus maximus * Separates mid-thigh into: * Tibial and Common Peroneal nerves * **Mixed Motor and Sensory Nerve** * Motor- posterior thigh, leg, and foot * Sensory - skin of posterior thigh/knee, lateral leg, foot

Answer 40

* Indications: * Anesthesia/analgesia to posterior distal thigh, posterior knee, lower leg/ankle/foot for surgery. * Ex: TKR * Advantage: * Complete blockade of leg in combo with femoral nerve block * Disadvantage: * Deep nerve structure → difficulty to identify (US + nerve stim) * Motor blockade can limit post-operative ambulation/physical therapy (foot drop) * So dense of block (may just do FNB w/ adjunct) May need to add saphenous or femoral NB to achieve medial aspect of knee

Answer 41

* Largest branch of lumbar plexus * Formed by dorsal divisions of anterior rami L2-4 spinal nerves * **Sx: Postop analgesia for anterior thigh/knee** * **Motor Innervation: Quads and sartorious** * **Sensory: Anterior thigh, anterior/medial knee, medial lower leg/ankle (saphenous n.)**

Answer 42

* Surgery to anterior thigh/knee * Quadriceps muscle bx, quadriceps tendon repair * **Knee arthroscopy/ACL, AKA/BKA, or TKR → may need to supp w/ opioid for pain control** * Complete blockade of lower extremity when combined **with sciatic nerve block**

Answer 43

* Disadvantage: * Loss of Quadriceps (motor) strength and control * Limits early postoperative ambulation and physical therapy (i.e. post knee replacement/reconstruction) (quad weakness) * Falling out of favor in lieu of Adductor Canal Block (keeps motor) * Contraindications: * Pre-existing femoral neuropathy * Local infection/Enlarged groin lymph nodes

Answer 44

* Common and useful block * Two nerves: Tibial and Common Peroneal together * Indications: ( BELOW KNEE) * Ankle and foot surgery, debridements, Achilles tendon, saphenous vein stripping * Advantage: * Spares posterior thigh (hamstring) muscle → don’t lose as much motor strength * Facilitates early physical therapy, post-op ambulation

Answer 45

* Posterior approach * PRONE * Landmarks: * Popliteal fossa crease * Tendon of biceps femoris * Tendon of semitendinosus * Lateral approach * Supine * Landmarks: * Popliteal fossa crease * Vastas lateralis * Biceps femoris

Answer 46

* Saphenous nerve (sensory) – branch of femoral * Anterior, medial knee/leg → picture! * Medial lower leg and ankle * Indications: * Knee analgesia (TKA, ACL, Foot/Ankle) * Supplement sciatic blocks (foot/ankle involving medial aspects), supp knee arthroplasty * Advantage: * Spares quadriceps (motor) * Allows for early ambulation/physical therapy

Answer 47

**Infiltration of Popliteal Artery and Capsule of Knee → MUSCLE STRENGTH SPARING TECH** * The IPACK block is performed for pain relief of posterior compartment of knee by anesthetizing the perforating branches of the sciatic nerve to periosteum without causing a foot drop (sciatic block does this but motor weakness left). * **LA in b/t spaces of Popliteal artery and posterior capsule of knee** * The IPACK is useful in surgical procedures such as: **ACL repair** with Allograft or patella tendon harvest (Avoid in Hamstring graft) or **Total Knee Replacements**. * Supplement w/ ACB or FNB * Common peroneal nerve palsy (CPNP) following total knee arthroplasty 0.3-0.4% after TKA. * Prolonged TQ use * Neuropraxia from mechanical stretching * Rheumatoid Arthritis

Answer 48

* Indicated for below the ankle procedures * Needle 22 G, 38mm B-bevel * Volume = 5-7ml per nerve * Do not use epinephrine * Essentially a field block—no nerve stimulator or US necessary * Nerves (5): field block * Posterior tibial nerve—posterior tip of medial maleolus and is located posterior to tibial artery * Deep peroneal nerve—lateral to dorsalis pedis pulse between the extensor hallucis longus and extensor digitorum longus * Saphenous nerve—2cm lateral to deep peroneal nerve in subcutaneous tissue * Superficial peroneal—blocked with a “ring” of subcutaneous LA to lateral aspect of ankle * Sural nerve—1cm distal to tip of lateral malleolus in subcutaneous tissue

Answer 49

* Preoperative education * Nutrition: * Carb loading (Gatorade), liberal fasting day surgery * Anemia optimization- baseline * Active prewarming of OR- optimal 36 deg * decrease bleeding, infections * Preemptive oral analgesia * Gabapentin, tylenol, Celebrex, N/V meds * Intraoperative anesthetic techniques * \*Regional- combo w/ GA? * Short-acting sedative-hypnotic agents * Goal-directed fluid therapy- not overloading * Normothermia * Blood conservation * Antibiotic prophylaxis * Postoperative analgesia * Postoperative * Multimodal opioid-sparing analgesia * regional, NSAIDS (Toradol), acetaminophen * PONV prophylaxis → #1 extended stay * Early mobilization * Early oral intake

Answer 50

* Acetaminophen * NSAIDS * Gabapentin * Methadone * tramadol * Ketamine- good adjunct * Lidocaine- running intraop low dose (midful if used during RA) * Dexmedetomidine * Beta-blockers

Answer 51

* Positioning * Intraop monitoring * Postop vision loss * Preexisting conditions: * Degenerative joint dx (RA) * Preop AW assessment!!!: mouth opening, neck ROM, C/S instability, previous surgeries in that area * Pulm dysfx: restrictive patterns (run pulm tests) * NM dx (contractures) * CV dysfx- muscular dystrophy, scolioisis (cor pulmonale/pulmHTN) → get EKG, ECHO * Neuro deficits: document preexisting deficits (pain localized, extent of motor weakness) * Recurrent chest infections * SC injury- vent dep

Answer 52

Anterior: (ACDF- anterior cervical disc fusions) * For access to upper thoracic and cervical spine * C/S issue already → may want fiberoptic/glidescope * GETA – *awake FO?* * Supine, bilateral upper extremities tucked * **IV Access- w/ add. IV** * Airway edema- extubation issue * EBL – minimal if no vascular injury * SSEP Posterior: * For access to mid thoracic spine and below. * GETA on stretcher * Prone, chest rolls * Arms at the side of the head (superman) or tucked * IV Access – *does it work?* * Facial edema/eyes – tell them to expect edema post op * EBL * Facial pressure points, groin and breasts. * SSEP

Answer 53

* For access to thoracic spine – help visualize/access anterior thoracic spine * Ex. Lateral lumbar interbody fusion * Vertebral body fusions, SC decompression, scoliosis, etx * Considerations: * May need one-lung ventilation * double-lumen ETT, bronchial blocker, lung packed * A-line to check ABG’s * Pad pressure points * Axillary chest roll

Answer 54

* ***IS THE NECK STABLE? ASK!*** * ***Position head to patient comfort while awake. Avoid “sniffing”. Avoid cricoid pressure.*** * Intubation * Consider awake fiberoptic * Long procedure w prolonged traction- may be prudent to leave intubated at end Anesthetic considerations * **Requires GA** * Indications: Trauma, spinal stenosis, tumor, arthritis * Airway compromise and vascular injury can occur * Hematoma/carotid artery damage → rapid blood loss * IMPEDE AW * Unilateral recurrent nerve damage- from instrumentation * Post-op pain-cervical plexus block Common Complications: * Dysphagia * Soft tissue swelling * Dural penetration * Esophageal penetration * Mechanical failure * Wound infections * Reasons why we don’t place OG tube

Answer 55

* Weighted plates can be provided to open up joints for c/s to visualize * Anterior approach-most common-esophagus and trachea medial & sternocleidomastoid and carotid sheath lateral. Following discectomy, vertebrae fused w bone, plates, and/or screws to prevent dislocation * Retraction of trachea extremely stimulating * Arms tucked to sides-assure IV access (extensions) * Posterior cervical decompression * Sitting: air embolism * Prone: eye damage, fluid overload and airway edema

Answer 56

**(4% of pop- 70% ideopathic)** * Lateral and rotational curvature of spine * Surgery indicated when: * Cobb angle = \>50 deg in thoracic area * \> 40 deg in lumbar * Associated with: * Restrictive pulmonary dysfunction: chronic hypoxia, hypercapnia, pulmonary vascular constriction (pulm HTN) * Eventually leading to → RV hypertrophy and cor pulmonale; MV prolapse, coarctation of heart, cyanotic heart disease

Answer 57

* Discectomy, Harrington rod, fracture stabilization, scoliosis correction, tumor resection * **Positioning**- Prone +/- anterior or lateral * _Neuromonitoring_: SSEP/MEPS, wake-up test * **EBL- LARGE AMOUNTS**- have units/cooler available * Considerable * Depends on number of segments fused * 3-4 units autologous * Techniques to combat: * Cell saver, **induced hypotension**, aprotinin (fibrin formation) * Hemodynamics * Induced hypotension (mean 55-60mmHg) * Aline, CVP, PA cath (+/-), foley. * Venous air embolism- rare but air may be entrained into venous network that surrounds dura mater and spinal cord * Valveless epidural veins make it easy * Postop care * Vent, ICU, PCA → PAIN REGIMEN NEEDED

Answer 58

* Discectomy, Laminectomy, fusion * Depends on complexity: 1-2 level or multilevel fusions * Prone * **EBL: Depends on number of segments fused/multilevel/instrumentation usage** * Take aways: * Intraop Pain mgmt. * Intraop hemodynamic stability/mgmt. * Postop pain mgmt.

Answer 59

**Somatosensory Evoked Potentials (SSEP): check for SC & nerve integrity** * Helps determine surgical impingement on spinal roots * Sensory- Monitor dorsal column pathways of posterior spinal cord * SSEPS recorded by stimulating peripheral afferent nerves * Intact nerve → electrical potential will transmit to contra lateral sensory cortex. * Recording electrodes are placed on the scalp and on the cervical spine. * Amplitude, shape, and latencies of the responses are monitored. * Need to establish a reproducible baseline recording prior to any positioning or surgical manipulations is important. * Changes from the baseline responses are the most important indicators of neurological dysfunction. * Latency & Amplitude → need baseline measurement * Anesthetics disturb L & A * VA \*\*

Answer 60

**\*Concern for nerve damage:** * **Amplitude = \> 50% change** * **Latency = \> 10% change** * Sx cause? Or hypotension, hypothermia, change anesthetic tech, etc **Anesthetic Considerations:** * Inhaled Anesthetics can alter the evoked responses significantly * VA = Dose dep decrease amplitude & increase latency * VA: (unreliable results). * 0.5 MAC w 50% N2O * decrease amplitude * increase (prolong) latency * Need to keep anesthesia consistent and notify them of changes to plan * IV anesthetics no impact → TIVA best (balanced technique good) * NMB do not adversely affect → SSEP used for posterior sensor component of spinal cord * Decreases in SSEP signal despite no change in anesthetic or no surgical changes may mean hypotension! ***Nerves get blood too!***

Answer 61

**Motor Evoked Potential = Anterior SC** * Motor Evoked Potentials * \*monitor descending motor pathways\* * **Concern:** * **Amplitude = \> 50% decrease** * **Latency = \> 10% decrease** * **Causes: damage by ischemia, metabolic change, mechanical trauma, compression** * Recorded from muscles following transcranial stimulation of the motor cortex to the peripheral muscles * To ensure the integrity of the descending motor tracts of the spinal cord * Agents: * VA- sensitive\*\* * IV anesthetics- less than VA * Opioids ok * Good drugs: propofol, remi, ketamine, dexmedetomidine

Answer 62

* Autologous donation * Cell saver\* * Antifibrinolytics such as tranexamic acid (TXA) * Positioning * Bleeding prone * Surgical technique * find suction canister locations

Answer 63

* Systemic Analgesics (IV, PCA) * Epidural Analgesic (PCE) and with local * 0.05% - 0.1% Bupivacaine w/ 2-5mcg/cc Fentanyl @ 3-10cc/hr. * Peripheral Nerve Blocks with Bupivacaine or Ropivacaine * Cervical plexus block * Non-steroidal anti-inflammatories as supplements- ERAS protocols * Wound LA infiltration * Methadone

Answer 64

* respiratory insufficiency * Monitor at level of injury * Muscles at C5 nerve root → diaphragm paralysis (respiratory issues!!) * AW obstructions * Rib fractures * Chest wall/facial trauma

Answer 65

* Immediately after SC injury and last up to 3 weeks * Injuries at or \> T5 injury → hypotension * d/t Physiologic sympathectomy occurring from injury → decrease tone on splenetic vascular beds * lesions on T1-T4 → decrease HR) * Hypotension from SCI DO NOT respond well to fluids/pressors → if try fluids can lead to pulm edema

Answer 66

* Autonomic hyperreflexia (complete transection injury \>T5) * 85% pts * Severe HTN w/ decrease HR from baroreceptor reflexes from continuous vasoconstriction * Triggering episodes: bladder/rectal distention → sz, intracranial hem, MI * Tx: immediate removal of stim, deepen anesthesia, vasodilators

Answer 67

* Succinylcholine (only use \< 48 hrs from injury) * \> 48 hrs → increase fetal acetylcholine nicotinic receptors → hypersensitivity to succs (HIGH K- as much as 14 mEq) * Highest risk = 4 wks-5 mo * VF → CV arrest

Answer 68

* Maintain normothermia * Disruption of sympathetic pathways that normally manage temp regulation → need to warm IV fluids, warm room, BAIR hugger

Answer 69

* Massive transfusion sequelae (from intraop BL) * VAE * Vision loss/blindness