Ortho/Podiatry Flashcards
Largest post operative problem for ortho/podiatry procedures
Post-op pain
-Regional anesthesia and multimodal analgesia utilized to address this
Rheumatoid arthritis
Chronic inflammatory process of uncertain etiology (autoimmune?)
- Synovitis of cervical spine, TMJ, larynx, and pulmonary system
- Rheumatoid nodules cause inflammation of intervertebral discs and atlanto-occipital subluxation (problem during intubation)
- Can cause limited TMJ opening
- Default=awake fiberoptic intubation
Hoarseness/inspiratory stridor indicates ___ for RA patients
Narrowing/fixation of glottis opening due to cricoarytenoid arthritis
RA pulmonary lesions
Can lead to many pulmonary diseases
- Pleural effusion
- Intrapulmonary nodules
- ILD
- Vasculitis
- Pulmonary infections
- Etc.
Osteoarthritis vs rheumatoid arthritis
Osteoarthritis -> bone on bone due to thinned cartilage
-“wear and tear” syndrome
RA -> Swollen/inflamed cartilage/synovial membrane -> bone erosion
-inflammatory disease of synovial membrane
Ankylosing Spondylitis
Chronic inflammatory process (primarily affects spinal column)
- Spinal injury with little trauma
- Conduction delays, valve lesions, restrictive lung disease
- Airway concerns, cervical spine positioning for intubation/intraop/emergence
- Many times C spine is fixed in flexed position -> awake fiberoptic intubation
Pneumatic tourniquet placement, inflation pressure, time of inflation
Should cover <50% of extremity and overlap away from superficial neurovascular bundle
- Inflate to 90-100 mmHg above SBP
- Notify surgeon at 60 minutes, shouldn’t exceed 120 minutes
Neurologic tourniquet hazards (30/60/120 minutes)
30 minutes: Abolish SSEP
60 minutes: Pain (even under deep anesthesia)
120 minutes: Neuropraxia (temporary loss of motor/sensory function due to blockage of nerve conduction)
-Nerve injury at edge of tourniquet can be permanent
Muscle tourniquet hazards (2 minutes, 2 hours)
2 minutes: Cellular hypoxia
-Creatinine values decrease
-Cellular acidosis
2 hours: Endothelial capillary leak
Systemic effects on tourniquet inflation
300-500mL blood pushed into systemic circulation -> increased systemic and pulmonary pressures
- Exaggerated when 2 limbs are occluded
- Potent anesthetic vapor blunts response more than balanced anesthetic technique
Systemic effects on tourniquet deflation
Decreased core temp
-Usually transient unless low to begin with
Transient metabolic acidosis
-Acidosis metabolites released into circulation
Decreased SvO2
Transient decreased systemic and pulmonary pressure
Transient increase in ETCO2
Tourniquet safety (2 hours, 4 hours, time to regain muscle power/sensation from 1 vs 3 hour T time)
2 hours: Shouldn’t exceed
4 hours: Reliable nerve damage will occur
3 hours: Muscle power of extremity reduced for a full week
1 hour: Physiologic effects of tourniquet deflation will resolve after 20 minutes
Complications of IV regional anesthesia
- LAST (avoid with maintaining pressure in reliable tourniquet)
- Hematoma (use a small IV and hold pressure for a long time after removing)
- Engorgement of extremity (happens when arterial inflow without venous outflow, make sure there isn’t a pulse)
- Exchymosis and subcutaneous hemorrhage (happens after engorgement, make sure theres padding under tourniquet)
Beach chair position complications
Cervical neck injury due to dislodgement of head from holder
- Inadvertent extubation
- Brachial plexus injury on opposite side
Advantages to beach chair position
- Reduced brachial plexus injuries
- Better respiratory mechanics
- Excellent access to shoulder
- Arm weight distracts shoulder joint
Hemodynamic hazards of beach chair position
CVP/MAP/PAP/CO decrease
-Inaccurate BP measurement if taken at arm (BP brain is 1mmHg less for every 1.25cm difference of auditory meatus from cuff site)
Vision loss after prone spine surgery (incidence, risk factors, presentation)
Incidence: 0.028-0.2% Risk factors: -Atherosclerosis, CV disease -Excessive blood loss -Excessive crystalloid administration -Excessive surgical length Presentation: Immediate post-op vision loss due to: -Cortical blindness -Central retinal artery occlusion -Ischemic optic neuropathy
How to avoid post-op vision loss
Avoid: -Direct pressure on globes -Periop hypotension -Periop anemia Consider 10 degrees reverse Trendelenburg when prone Lower transfusion threshold (Hct>30% in at risk patients) Avoid large amounts of crystalloid Maintain MAP at pts baseline
Arthroscopy
Examination/treatment of joint space with endoscope
- Usually knee but also shoulder, wrist, hip, ankle
- Less blood loss, post-op pain, short/no hospitalization, short rehab
Arthroplasty (what it is, goals, most common type)
"Total joint replacement" Surgical replacement of all/some joint -Goal: Pain relief, stability, deformity correction Knee=most common -Use tourniquet -Usual blood loss up to 2 units
Anesthetic for knee arthroplasty
General
Spinal
“Triple” block
-Femoral, sciatic, lateral femoral cutaneous nerves
TKA adverse events
HTN, hypoxia, CV collapse during component insertion Cases: -MMA cement -Fat embolism -Air embolism -Marrow embolism -Thromboembolism
CV effect of MMA cement
Increased PVR and PCWP
Decreased SVR, CO, BP
PE incidence for TKA
1-5%
Very high, usually get LMW heparin and/or Coumadin post op
Special considerations for THA
Blood loss can >6 units
MVAMC redo’s get a line and foley
Usually older patients with co-morbidities
Methylmethacrolate cement (MMA)
Binds with patients bone and prosthetic parts
Hardens and expands due to exothermic reaction
Can cause intramedullary hypertension -> embolization of fat, bone, cement, and/or air
Bone cement implantation syndrome (and risk reduction strategies)
-Hypoxia
-Hypotension
-Arrythmias
-Pulmonary hypertension
-Decreased CO
Usually occurs when femoral component is placed
Risk reduction strategies
-Increase FiO2 before cementing
-Maintain euvolemia
-Vent distal femur and do high pressure lavage of femur shaft to remove debris
-Use uncemented femoral components for hips
-Avoid hypothermia
Methods to conserve blood during ortho surgery
- Cell saver
- Autologous blood
- Induced hypotension (be careful)
- Normothermia
- Spinal or epidural anesthetics
Indications for spinal surgery
Intervertebral disc herniation or spinal stenosis scoliosis
- Herniated disc excised and foramen is enlarged
- Vertebral fusion with bone grafts or vertebral cages
Special considerations for scoliosis surgery
Typically anterior/posterior surgery
- Requires thoracotomy to access thoracic spine
- May have some restrictive lung disease depending on disease progression
Foot and ankle surgery indications and anesthesia type
Ankle fraction, Achilles tendon rupture, bunions, hammer toes, plantar fasciotomy, toe/foot amputations
-Very amendable to regional anesthesia
5 nerves for ankle blocks
Branches of sciatic nerve: -Superficial peroneal -Deep peroneal -Sural -Posterior Tibial Branch of femoral nerve: -Saphenous *All 5 must be accurately blocked for efficacious ankle block
Hip fractures
- Usually elderly with many co-morbidities
- Usually off-shift
- Blood loss pre- intro- and post-op
- Lateral position
- Use of regional anesthetics is limited by patient conditions and co-morbidities
- High incidence of post-op complications
2009 Article gerontology post-op complications correlated with ___
- Poor ASA classification
- Urgency of procedure
- Extent of procedure
- Duration of procedure
ORIF major complication
Fat embolism
-10-20% of femur fractures, often fatal
-Due to fat globules released by the disruption in fat cells in bone fracture, enter the circulation through tears in venous sinuses in the bone
-Present in 72 hours of injury, sx: dyspnea, confusion, petechai
Dx: petechai on chest/UE/axilla/conjunctiva
-Fat globules in retina, sputum, urine
-Thrombocytopenia
-Decreased ETCO2, SaO2, increased PA pressures
-ST segment suggestive of ischemia
Treatment
-Stop operating on bone, supportive care
On an upright CXR where should the end of the ETT be?
Where clavicles meet
Bier block, what to check
Both sides of tourniquet are working (250mmHg and 270 mmHg)
-Distal and proximal cuffs and labeled and correctly correlate with box labels
Onset of bier block
5 minutes
Midazolam for bier block?
Yes, increases comfort and increases seizure threshold if tourniquet is inadvertently released and high lidocaine doses are released systemically
Hypoxic pulmonary vasoconstriction
Alveoli without much O2 vasoconstrict, shunt blood flow to areas of lungs with better ventilation
-Normalizes V/Q mismatch
What NOT to use in blocks for patients with diabetes
Epi
Fracture table positioning considerations
Don’t forget about the unaffected leg that is raised above the body (BP will be decreased here compared to cuff reading), make sure it’s perfused
Ankle block=block of the terminal branches of the ____ nerve
Sciatic nerve
Except 1 nerve branch of femoral
Ankle block=block of 2 deep nerves __,__ and 3 superficial nerves __,__,__
Deep -Deep peroneal -Posterior tibial Superficial -Saphenous -Sural -Superficial peroneal
Anesthetizing superficial vs deep nerves
Deep
-Anesthetized by injecting local anesthetic underneath the superficial fascia
Superficial
-Anesthetized by a simple subcutaneous injection of local anesthetic
Sciatic nerve formed from __ through __ roots
L4-S3 roots
1st split of sciatic nerve
To tibial nerve and common peroneal nerve
Femoral nerve arises from ___ nerves, and what it’s positioned next to running down
L2-L4
Lateral and slightly deeper than femoral artery
Ankle block provides anesthesia to:
Foot, but NOT the ankle itself
Local anesthetics to use for ankle blocks (3)
1.5% Mepivicaine (with bicarb)
2% Lidocaine (with bicarb)
0.5-0.75% Ropivicaine
0.5% Bupivicaine
Complications of ankle blocks
Injection Hematoma Vascular injection -Especially at saphenous vein at medial malleolus Nerve injury
Bezold-Jarisch reflex
Inhibitory reflex mediated through cardiac sensory receptors with a vagal efferent limb
-Beach chair position -> venous pooling in dependent extremities -> increased sympathetic tone, low-volume hypercontractile ventricle -> reflex activated -> abrupt automatic withdrawal of sympathetic response, activation of increased vagal tone
=sudden profound bradycardia and hypotension that’s difficult to rapidly reverse
Blocks and hypotensive bradycardic episodes (HBE)
LA with epi for interscalene block might contribute to HBE (hypotensive bradycardic episodes) d/t increased cardiac contractility -> ventricular emptying -> increased HR (reduced cardiac filling) -> increased peripheral vasodilation and pooling (decreased afterload) -> ventricular hypovolemia with hypercontractions
Prophylaxis to prevent HBE
- Aggressive treatment of fluid deficits and blood loss
- Support stockings: Minimize venous pooling in upright position
- Avoid LA with epi
- Consider using intraoperative beta-blockade in select patients
Risk of developing ___ is increased with pneumatic tourniquet use
Thromboembolism
Spine procedures more likely to be associated with major blood loss
Those involving the thoracic spine, particularly for malignancy or trauma
TXA MOA
Inhibits fibrinolysis by blocking the activation of plasminogen resulting in clot stabilization -> reduced post-op bleeding