ANESTHESIA FOR ORTHOPEDIC SURGERY
David Hirsch M.D.
“There is a fracture, I need to fix it.” (http://www.youtube.com/watch?v=3rTsvb2ef5k)
Disclosures
none
Topics
Special considerations Hip Surgery Knee Surgery Upper Extremity Spine Surgery Peripheral Nerve Blocks
Special considerations
Bone cement (polymethylmethacrylate) Binds prosthetic device to patient’s bone Can cause embolization of fat, bone marrow,
cement and air into femoral venous channels Most frequently with femoral prosthesis
Bone Cement Implantation Syndrome Hypoxia – increased pulmonary shunt Hypotension Dysrhythmias- heart block and sinus arrest Pulmonary hypertension – increased PVR Decreased cardiac output
Bone Cement
Anesthetic Strategy Maximize Fi02 Eu-volemia (monitor CVP) Vent hole in distal femur to decrease pressure High pressure lavage to remove debris
Tourniquet
Help create bloodless field Can cause pain, metabolic alterations, hemodynamic changes Increase in blood flow in central circulation Pain severe enough to require substantial supplementation
despite regional block Goal < 2 hours
Can cause transient muscle dysfunction Permanent peripheral nerve damage Rhabdomyolysis
Lower Extremity Can lead to DVT
Sickle Cell Pay attention to maintaining normocarbia, hydration,
normothemria
Tourniquet
Deflation Fall in CVP, ABP Pulse increase Temp Decrease Increased PaC02,EtC02, lactate and potassium
from ischemic limb Cause increase in Minute Ventilation Rare-dysrhythmias
Re-oxygenation Can worsen ischemic injury due to formation of
lipid peroxides
Emboli
Fat Embolism Syndrome 10-20% mortality Within 72 hours following long-bone or pelvic
fx Triad of dyspnea, confusion and petechiae
1)Fat globules released by disruption in bone enter circulation through tears in medullary vessels
2) or chylomicrons resulting from aggregation of circulating free fatty acids
Embolism
Symptoms Coagulation Abnormalities
Thrombocytopenia, increased clotting time Pulmonary
Range from Mild hypoxia to ARDS Under GA
Decline in ETCO2, arterial oxygen saturation Increase in PAP ECG-ischemic ST changes and right sided heart strain
Treatment: Prophylactic: early stabilization of fracture Supportive: 02, with CPAP, high dose
corticosteroid
Fat Emboli
DVT/PE
Increased risk DVT/PE Higher risk
Obesity, age > 60, procedure > 30 min, tourniquet, LE fracture and immobilization > 4 days Older studies: PE as high as 20% with 1-3% fatal PE
Anticoagulation as soon as possible Improvement in occurrence rate
prophylaxis early rehab regional anesthesia?
DVT/PE
Neuraxial Anesthesia Alone or with general can reduce embolic
complications Sympathectomy induced increase in LE venous blood
flow Systemic anti-inflammatory effect of local anesthetic Decreased platelet reactivity Increase in factor 8,vW Decrease in Antithrombin III Decrease in stress hormone release
Contraindicated with full anticoagulation therapy Generally not done within 6-8 hour prophylactic
heparin dose or 12-24 hours of LMWH
Hip Surgery
Pre-op Mostly elderly Pre-op hypoxia
Fat emboli, bibasilar atelectasis, pulmonary congestion/effusion or infection
General vs. regional Lower mortality early post-op period for
regional After 2 months, no difference in mortality
Spinal Hypobaric technique allows easier positioning
Total Hip Arthoplasty
Etiology Osteoarthritis: repetitive trauma Rheumatoid Arthritis
Atlanto-axial instability: Preoperative:
Flexion and extension radiographs of the cervical spine:
Especially those on immune therapy, steroids methotrexate
Intubate with fiberoptic/video assist Limited jaw mobility
Total Hip Replacement
Intra-op Lateral Decubitus +/ - Arterial Monitoring Considerations
Bone Cement Implantation Syndrome Blood Loss Thromboembolism
Most often during insertion of femoral prosthesis
Total Hip Arthoplasty
Bilateral Recommended to monitor PA pressure in case
of emboli PAP> 200 during first hip, contralateral should
be postponed Revision
Significant blood loss If possible, controlled hypotension
Knee Surgery
Knee Arthroscopy Knee Replacement
Knee Arthroscopy
Pre-op considerations Usually young/healthy however increasing
frequency in elderly Intra-op Management
Surgeons favor bloodless field (tourniquet) LMA Neuraxial vs. alternative regional
Post-op Pain Control Multi-orifice catheter (Painball) Corticosteroid injection
Knee Surgery: Regional
Regional: 3 options Femoral with or without sciatic block Psoas Compartment Block Local Infiltration
Total Knee Replacement
Pre-op Usually secondary to OA/RA
Intra-op Blood loss decreased by tourniquet Bone cement implantation syndrome less
likely then hip Regional technique similar to Arthroscopy
Continuous catheter (Epidural vs. femoral)
Upper Extremity Shoulder
Open or Arthoscopic Lateral Decubitus or Beach Chair
Interscalene block preferred +/- interscalene catheter Side effects:
Phrenic nerve palsy Horner's syndrome
Mild controlled hypotension requested Elbow
Open or Arthoscopic Infra-clavicular block preferred
Beach-Chair Position
Head and Upper torso elevated 30-90 degrees Complications
Stroke, Ischemic Brain Injury and Vegetative State Decreased cerebral Perfusion Each cm of head elevation above heart there is a
decrease in arterial blood pressure of .77 20 cm not uncommon
Approximately 15-16 mm Hg gradient from heart/cuff Measure height difference at External Auditory
Meatus Same level of Circle of Willis
Avoid in Elderly, HTN Compromised autoregulatory curve
Spinal Surgery
Most common Posterior spinal fusion Scoliosis correction Combined antero-posterior procedures
Anesthetic Considerations Neuro-monitoring
Awareness (+/- BIS) Position
Often prone for long periods of time Mayfield tongs or Prone Pillow
Blood Loss
Post-Operative Vision LossCases > 6 hour with > 1 L blood loss highest risk
Ischemic Optic Neuropathy Variation in blood supply Orbital Edema
Increased venous pressure can cause decreased arterial flow
Ocular Perfusion Pressure Function of MAP and IOP (Intraocular Pressure) OPP = MAP – IOP Prone position associated with increased IOP
Central Retinal Artery Occlusion Emboli Direct pressure on Eyeball
Post-Operative Vision Loss
Visual loss Registry with ASA Most Healthy/Prone position
93 total 83 Ischemic Optic Neuropathy 10 Central Retinal Artery Occlusion 55 bilateral
Mean blood loss 2 L Range .1 – 25 L
Blood loss > 1L and case longer then 6 hour = 96%
References
Butterworth IV JF, Mackey DC, Wasnick JD. Chapter 38. Anesthesia for Orthopedic Surgery. In: Butterworth IV JF, Mackey DC, Wasnick JD, eds. Morgan & Mikhail's Clinical Anesthesiology. 5th ed. New York: McGraw-Hill; 2013. http://www.accessmedicine.com/content.aspx?aID=57236471. Accessed June 12, 2013.
Chelly, Jacques. Peripheral Nerve Blocks: A Color Atlas. 2009.
Miller, Ronald D. and Manuel C. Pardo. Basics of Anesthesia , Sixth Edition.Chapter 32 , 499-513Copyright © 2011,
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