Ortho Flashcards
Polymethylmethacrylate
- Bone cement
- Frequently required for joint arthroplasties
- Binds prosthetic device to the patients bone - causing an increase the intramedullary pressure
Complications when intramedullary pressure increases
o Fat, bone marrow, cement, or air emboli
o Vasodilation and ↓ in SVR
o Platelet aggregation and microthrombus formation
o Hypoxia
o Hypotension
o Dysrhythmias
o Pulmonary hypertension an increase in PVR
o ↓ CO
Interventions for increased intramedullary pressure (w/ bone cement)
o Increase FiO2
o Maintain euvolemia
o Treat arrhythmias
o Surgeon can create a vent hole in the distal femur to relieve intramedullary pressure
Pneumatic Tourniquets:
• Creates a bloodless field that facilitates surgery
Pneumatic Tourniquets: inflation pressure
100 mmHg over systolic blood pressure
Pneumatic Tourniquets:
Prolonged inflation of >2 hours can lead to
transient muscle dysfunction / myopathies / pain
o peripheral nerve injuries
o rhabdomylsis
Pneumatic Tourniquets:
Other potential problems
o Hemodynamic changes o Pain o Metabolic alterations o Arterial thromboembolism o Pulmonary embolism • Tourniquet pain
Tourniquet pain
un-myelinated slow conducting C-fibers
o Pain usually begins 45-60 min into procedure
o Pain may become so severe that patients may require GA despite the regional block – Spinal Anesthetic
o Progressive sympathetic activation
o Cuff deflation immediately relieves tourniquet pain and associated hypertension
o When the tourniquet is released you will see….
cause ↑’s in PaCO2, ETCO2, serum lactate and potassium levels
When applying the tourniquet
Limb must be padded and the cuff must fit and be properly applied to the correct extremity
Fat Embolism Syndrome: presents in -
72 hours of long bone or pelvic fractures
o long bones = femur / humerus / pelvis
Fat Embolism Syndrome: Signs and symptoms:
o Dyspnea, hypoxia
o Confusion or agitation
o Petchiae on the chest, upper extremities, axillae and conjunctiva
o Fat globules may be found in the retina, urine or sputum
o During GA: ↓ ETCO2 and arterial O2 saturation, ↑ pulm artery pressure
Fat Embolism Syndrome: mechanism
not known but is thought to occur due to the release of fat globules from fractured bone which enter torn medullary vessels
Fat Embolism Syndrome: Treatment
o Early fracture stabilization
o Oxygen and intubation with continuous positive airway pressure ventilation
o If the patient is coding - Start ACLS protocol
o High dose corticosteroids may be of beneficial use
Deep Vein Thrombosis & Pulmonary Embolism
- Most common after orthopedic surgery on the pelvis and lower extremities
- Occurs due to venous stasis and a hypercoagulable state due to localized and systemic responses to surgery
Deep Vein Thrombosis & Pulmonary Embolism
- pts at risk
Hip surgery or knee reconstruction patients o Obese patients o Over the age of 60 o The use of a tourniquet o Greater than 4 days immobilization
how to decrease risk of DVT and PE -
• Prophylactic anticoagulation and use of pneumatic leg compression devices decreases incidence of DVT
• If patients are on anticoagulation prophylaxis, spinal or epidural needle placement or catheter removal should
not take place until 6-8 hours after heparin dose or 12-24 hours after LMWH
• Anticoagulants may be started after surgery -
o Heparin 5,000 units q8˚ or LMWH
Compartment Syndrome:
there is an increased pressure – typically caused by inflammation – within the facial compartment – which first impairs venous and lymphatic drainage and eventually arterial blood flow to the tissues – this decreased blood flow to the tissues can lead to nerve damage and muscle death
Compartment Syndrome:
Most commonly seen in
anterior and posterior compartment of the leg
Compartment Syndrome:
increased pressure impedes
venous, lymphatic and eventually arterial flow
Compartment Syndrome: reduction of blood flow causes
ischemia, pain, and may cause paresthesias
• Can lead to nerve damage and muscle death if severe and untreated
Compartment Syndrome: treatment
medical emergency and requires a fasciotomy
