Orthopedic Surgeries

Preoperative assessment

Osteoarthritis (OA) / Degenerative Joint Disease

Degenerative process affecting articular cartilage of one or more joints, most commonly knee and hip. The spine is often involved, so be careful with neck position during intubation. Often due to wear and tear (think age, obesity). Minimal inflammatory reaction

Rheumatoid Arthritis

Prevalent in the orthopedic population and may involve pulmonary (pleural effusion), cardiac (pericardial thickening and effusion, conduction defects, cardiac valve fibrosis), and musculoskeletal systems (usually multiple joints, symmetrical involvement). It differs from OA as it is an immune-mediated joint destruction due to inflammatory processes in the synovial membranes

• Cervical spine: limited neck ROM, influencing airway management
• Temporomandibular joint (TMJ): pain and limited mouth opening (may require fiberoptic nasal intubation)
• Larynx: possible cricoarytenoid joint arthritis (note hoarseness), requiring the use of a smaller ET tube

Advanced RA patients are at high risk for compression of the spinal cord with intubation due to cervical instability, and some require pre-op X-rays. RA patients may be on steroids; note for perioperative steroid treatment, be aware of thin and atrophic skin, adrenal insufficiency, and impaired immune system

Both diseases can mask cardiac disease as patients have low exercise tolerance due to pain and joint restrictions

Anesthetic Considerations

Regional advantages

• Improved post-op analgesia (can add analgesic to spinal/epidural and administer locally into the surgical site)
• Decreased risk of N/V
• Less cardiac and respiratory depression
• Improved perfusion via sympathetic block (vasodilatation from Spinal)
• Reduced risk of delirium in elderly patients

Potential for Increased Blood Loss

Induced hypotension during surgery, keeping MAP >65 and/or within 20 to 30% of baseline MAP for HTN patients

Evaluate ongoing blood loss, note field bleeding, laps=100ml/ 4x4=10ml

One unit of RPBC increases Hct 2-3%/Hgb 1gm  

Use of blood salvage techniques

• Autologous blood donation
• Hemodilution before loss of blood
• Cell saver during surgery
• Acute normovolemic hemodilution (ANH)
  • Tap blood at the beginning of the case, anticoagulated blood, give crystalloid, save at room temp for up to 8 hrs, transfuse as needed. Hgb must be >11

Potential for Fat Embolus Syndrome (FES)       

Seen with multiple traumatic injuries and surgeries involving long bone fractures. Mortality 10-20%. Must have one major and a minimum of four minor symptoms

Risk Factors

Male

Age 20-30 yrs

Hypovolemic shock       

Intramedullary instrumentation

Rheumatoid arthritis

Total hip arthroplasty using cementing femoral stems

Bilateral knee surgery

Symptoms

Major

• Axillary or subconjunctival petechiae
• Hypoxemia (PaO₂ <60, FIO₂ <0.4)
• CNS depression
• Pulmonary edema

Minor

• Tachycardia >110
• Hyperthermia
• Retinal fat emboli
  • Multiple white retinal patches and retinal hemorrhages are associated with severe vision loss
    • Known as Purtscher’s retinopathy
• Urinary fat globules
• Decreased platelets/hematocrit
  • If unexplained
• Fat globules in sputum
• Increased erythrocyte sedimentation rate
  • The classic sedimentation rate is how far the top of the RBC layer has fallen (in millimeters) in one hour
  • The sedimentation rate increases with more inflammation

Treatment

Nonspecific, only supportive (oxygenation, hydration, nutrition, prevention DVT/stress ulcer)

Methyl Methacrylate (Bone Cement)

• It may cause sudden onset of hypotension
• Prevent by administering adequate hydration and maximizing inspired O₂ concentrations
• As air can get entrained during reaming and application of cement, avoid nitrous oxide several minutes before this point of the procedure

Potential for Venous Thromboembolism

A significant cause of death after trauma/surgery to lower extremities. Evaluate risk factors (advanced age, prolonged immobility or bed rest, prior history, cancer, pre-existing hypercoagulable state)

Hip surgeries pose the most significant risk

Use of Tourniquet for Extremity Procedures

Reduce surgical blood loss

Decreased blood in the field, which helps reduce operating time

Max 300 mmHg for UE and 500 mmHg for LE

• The best practice is to go 100 mmHg above SBP

Effects of tourniquet inflation: cellular hypoxia within 2 min, progressive cellular acidosis, an endothelial capillary leak develops after 2 hr, no somatosensory evoked potentials, and nerve conduction after 30 min

• Nerve injury may occur after 2 hr of application - may resolve within 4-6 weeks
• TOTAL tourniquet time should be less than 2 hrs
• Remind the surgeon of the time and note on the anesthesia record

Tourniquet pain manifesting after 45-60 min, leading to increased HR and BP

• Burning and aching corresponds to the activation of the small, slow-conducting, unmyelinated C-fibers)

Effects of tourniquet release: transient fall in core temp (0.6 °C for every hr), metabolic acidosis (increase K⁺, CO₂, bicarbonate), fall in pulmonary and systemic arterial pressures, increase in ETCO₂, release of acid metabolites (thromboxane - part of the lipid family eicosanoids) into the central circulation

• Acute reperfusion of a limb with about 500 mL of blood may cause hypotension

Potential for Hypothermia

Monitor the patient's temp via esophageal probe, skin, or F/C during the procedure

• The Society of Critical Care Medicine's Fever task force concluded that IV or bladder thermistor measures temperature most accurately

Use warming devices in the OR such as Forced air warmer and hot fluid lines. Cover the patient's head as much as possible (large area of heat loss)

Room temperature regulation as needed

Potential for Infection

Administer antibiotics within 60 min of incision (Vancomycin within 120 min)

Monitor regional sites for infection 

Positioning Considerations

Increased risk of injury with various positions requiring diligence by the providers

Pad pressure points (note ring under the ear, monitor pressure on the eye if lateral), ulnar nerve padding, prevent alopecia

Avoid hyperflexion of limbs/brachial plexus