Anesthesia for Orthopedic surgery

อรุณชัย นรเศรษฐกมล

Content

  General consideration 

Age-specific orthopedic conditions

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Medical comorbidities Coexisting medication

Specific consideration 

Positioning

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Bone cement Pneumatic tourniquet

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Fat embolism Deep vein thrombosis & Thromboembolism

Age-specific orthopedic condition  Young adult  ACL reconstruction, Rotator cuff  Elderly  Hip, Knee arthroplasty  Hip Fracture  Children  Congenital orthopedic surgery

Medical comorbidities  Elderly patients  Multiple organ dysfunction  Rheumatoid arthritis  Osteoarthritis  Ankylosing spondylitis

Rheumatoid arthritis problem should be aware  Cervical spine instability  IV access  Systemic involvement  Airway management  Spinal or epidural may be difficult  Positioning

Osteoarthritis

Joint usually involved in Osteoarthritis

Osteoarthritis ( OA) problem should be aware  Reduced joint movement  Airway management  IV access  Spinal or epidural may be difficult  Positioning  Concurrent analgesic therapy

Ankylosing spondylitis (AS) problem should be aware  Fix flexion deformity  Regional anesthesia may be difficult  Abnormal spread of local anesthetics

Coexisting medication  Antihypertensive drugs  Steroids  Aspirin  NSAIDs  Opioid analgesics  Immunosuppressive drugs

Specific consideration

Positioning  Supine  Lateral  Prone  Beach chair  Fracture table

Why is positioning important?

 Enable IV and catheter to remain patent  Enable monitors to function properly  Facilitates the surgeon’s approach  Patient safety

Supine  Patient on back  Arms on arm boards  Arm < 90 degrees  Arm is supinated ( palm up)  Place padding under elbow if able  Arm tucked  Check fingers  Check IV lines and SaO2 probe

Lateral  Body alignment  Keep neck in neutral position  Always place axillary roll  Place padding between knees  Place padding below lateral aspect of dependent leg

Lateral  Position arms to parallel to one another  Place padding between arms or place non-dependent arm on padded surface

Prone  Face down  Head placement  Head straight forward  ET tube placement and patency  Check bilateral eyes/ears for pressure points  Head turned  Check dependent eye/ear, ETT placement  Be aware of potential vascular occlusion

Prone  Arm placement  Tucked – similar to supine  Abducted  Check neck rotation and arm extension to avoid brachial plexus injury  Elbow are padded  Chest rolls  Iliac support  Padding in placed under iliac crests

Injury occuring from prolonged positioning  Eye compression in prone position  Skin breakdown due to prolonged positioning

Bone cement Polymethylmethacrylate: MMA

Bone cement implantation syndrome ( BCIS)  Release of vasoactive and myocardial depressant substances  Intravascular thrombin generation in the lungs  Direct vasoactive effects of absorbed MMA  Acute pulmonary microembolization

Clinical presentation          Fever Hypoxia Hypotension Tachycardia Dysrhythmia Mental status change Dyspnea End tidal CO2 decrease Right ventricular failure and cardiac arrest

Management  Supportive care  Monitoring vital signs  O2 supplement  IV fluid  Vasopressor

Pneumatic tourniquet  No more than 2 hours  100 mmHg above systolic blood pressure  250 mmHg for arm  350 mmHg for leg

Pneumatic tourniquet  Advantage  Eliminate intraoperative bleeding  Disadvantages  Neurologic effect  Muscle change  Systemic effects of the tourniquet inflation  Syeyemic effects of the tourniquet release

Neurologic effects  Tourniquet pain and hypertension If > 45-60 mins  Neurapraxia if > 2 hours  Nerve injury at the skin level the edge of the tourniquet

Muscle changes  Cellular hypoxia  Cellular acidosis  Endothelial capillary leak  Limb becomes colder

Systemic effect of tourniquet inflation  Arterial pressure elevated

Systemic effect of tourniquet release  Transient fall in core temperature  Transient metabolic acidosis  Release of acid metabolites into central circulation  Transient fall in arterial pressure  Transient increase in EtCO2

Prevention  Select patients  Wide, low-pressure cuff  Apply the lowest pressure to prevent bleeding  Limit time to 2 hours  Set maximum pressure  Arm 50-75 mmHg above systolic  Leg 75-100 mmHg above systolic  Adequate padding underneath

Fat embolism  The mechanical theory  The biochemical theory

Clinical finding       Cardiovascular  Persistent tachycardia, hypotension Respiratory  Dyspnea hypoxia hemoptysis Cerebral  Delirium stupor seizure coma Ophthalmic  Retinal hemorrhage Cutaneous  petechiae Other  Jaundice fever

Treatment  Prophylactic  Early stabilization of the fracture  Supportive  Respiratory care  Maximize O2, ventilation  Invasive monitor  Volume status  Inotrope  High dose corticosteroid

Deep vein thrombosis & Thromboembolism

lower extremities, pelvis  Major pathophysiological mechanism  Venous stasis  Hypercoagulable state  Endothelial damage

Risk Factor  Obesity  Age > 60 years  Procedure > 30 mins  Use of tourniquet  Lower extremities fracture  Immobilization > 4 days

Prevention  Prophylactic anticoagulant  Low dose heparin  Warfarin  LMWH  Intermittent pneumatic compression  Neuraxial anesthesia reduce thromboembolic complication

Major orthopedic procedure  Total hip replacement  Fracture of the hip  Total knee replacement  Spinal surgery

Hip surgery  Patient  Limit ability to exercise  Cardiovascular function can be difficult to assess  Elderly with systemic disease, OA,RA  Blood loss  Use of hypotensive technique or reginal anesthesia reduces blood loss

 Positioning  Mostly lateral decubitus position  Ventilation perfusion mismatch  Neurovascular problem

Potentially life-threatening complication  Bone cement implantation syndrome  Intra and postoperative hemorrhage  Venous thromboembolism

Important factor of mortality  Very old age  Female>male  Hip fracture  Obesity  Smoking  Malnutrition  Baseline cardiopulmonary function

Anesthetic concerns  Invasive monitoring  Blood loss  Positioning  Cement fixation  Deliberate hypotension

GA or RA  GA  Decrease lung function  Depress cough  Increase secretion  Depress cardiac function  RA  Reduce lung complication  Reduce thromboemboli  Reduce delirium  Reduce blood loss

Revision hip arthroplasty  Blood loss  Longer duration  Deliberate hypotension or regional should be used

Total knee arthroplasty  Preoperative consideration  Same as THR  Severe rheumatoid arthritis  Osteoarthritis  Obesity  comorbidity

Anesthetic management  Thromboembolism  Fat embolism  Cement  Postoperative blood loss  Postoperative pain; more than THR