Anesthesia for Orthopidic Surgery Flashcards
What are some special consideration in ortho surgery?
- Bone cement
- Pneumatic tourniquets
- Fat embolism syndrome
- Deep venous thrombosis
- Thromboembolism
Characteristics of bone cement:
- Exothermic reaction resulting in hardening
- Heat, expansion and hardening lead to intermedullary hypertension (>500 mm Hg)
- Residual mma monomer produces vasodilation, decrease in SVR
- Tissue thromboplastin release may cause platelet aggregation microthrombus (lungs) and CV instability
What symptoms correlate with bone cement implantation syndrome:
- Hypoxia (increased pulmonary shunt)
- Pulmonary HTN (increase PVR)
- Dysrthythmias (Heart blocks / Sinus arrest)
- Hypotension
- Decreased CO
- Embolization most frequent during prosthetic insertion
What are the strategies to limit MMA (Bone Cement) effects:
-Increase inspired O2 prior to MMA (bone cement)
-Maintain euvolemia
-Vasopressor as needed
SUGICAL METHODS
-venting distal femur
-high pressure lavage of femoral shaft
What kind of hemodynamic changes will be seen with pneumatic tourniquets?
- Increase B/P
- Increase HR
What are the problems with pneumatic tourniquets?
- hemodynamic changes
- Pain
- Metabolic changes
- Arterial thromboembolism
- Pulmonary embolism
- Muscle and nerve injury
- Limb cooling
Prolonged cuff time of __ to __ minutes associated with HTN, ________, ___________ stimulation (sweating).
45 to 60
tachycardia
sympathetic
What will the deflation of the Pneumatic cuff do to the hemodynamics?
- Decreases CVP
- Decreases MAP
T/F: The core temperature drops with the use of a pnuematic cuff.
TRUE
Pneumatic cuff pressure should be ____ torr above systolic pressure or the upper extremity should be ___ torr and the lower extremity ___ torr.
100
250
350
What kind of pain is associated with the tourniquet?
-Sever aching and burning (several minutes)
-Unmyelinated, slow conduction C fibers
Supplemental analgesia needed
T/F: Tourniquest pain is less common in general anesthesia then in regional anesthesia.
FALSE (…. less common in regional anesthesia then in general anesthesia.)
What metabolic changes are noticed with the tourniquet?
- Waste accumulation in the tissue
- Cuff deflation is rapid wash out which will increase PaCO2, ETCO2, serum lactate, and potassium.
- With deflation an increase in spontaneous breathes and possible disrhythmias
- Re-perfusion injuries from free radical formation
T/F: Tourniquet contraindicated in calcified artery.
TRUE
T/F: Tourniquet ischemia is NOT associated with upper/lower extremity that leads to a deep venous thrombosis.
FALSE (It is associated and is more common in the lower extremity)
Prolonged inflation of the tourniquet > _ hours leads to transient _______ and permanent _____ injury.
2
muscle
nerve
T/F: Rhabdomyolysis can be associated with prolonged tourniquet times.
TRUE
What is the triad of fat embolism syndrom:
- dyspnea
- confusion
- petechiae (pathognomonic)
Classic presentation of fat embolism syndrome with in __ hours of ____ bone or ______ fracture.
- 72
- long
- pelvic
What other modalities can cause fat embolism syndrome?
- CPR
- Liposuction
- IV lipids
How do fat emboli enter into circulation:
medullary vessel
Increased fatty acid levels toxic to capillary alveolar membrane releasing vasoactive ______ and ____________.
- amines
- prostaglandins
What type of coagulation effects will be seen with fat embolism syndrome.
- Thrombocytopenia
- Prolonged clotting time
What kind of pulmonary symptoms will be seen with fat embolism syndrom?
- Progressive pulmonary involvement from mild hypoxia and clear CSR to ARDS
- Under GETA see decline in ETCO2 and SpO2 and rise in PAP