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31 Cards in this Set
- Front
- Back
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What degree of scoliosis causes severe cardiac and respiratory dysfunction?
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>100 degrees
-if <65 degrees respiratory impairment is minimal |
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In a scoliosis patient what vital capacity should concern you for possible need for postop ventilation?
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VC < 40% predicted
-if >70% patient should be fine postop |
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What are the pulmonary problems encountered in severe scoliotic patients?
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1. restrictive lung disease - decreased VC, TLC, RV, FRC, increased VD/Vt which causes increased A-a gradient, alveolar hypoventilation, hypoxemia, nml PaCO2
2. chronic hypoxia - can lead to pulm htn and cor pulmonale (RVH, RAD, RBBB) |
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What cardiac valvular problem is often seen in patients with scoliosis?
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mitral valve prolapse (25%)
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What are frequent findings in CXR in patients with severe scoliosis?
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chronic aspiration pna
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What inhaled agent should you avoid in patients with severe scoliosis?
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N2O bc it can worsen pulm htn (as do acidosis, hypoxemia, and hypercarbia)
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What lung complication is more common in patients with severe scoliosis compared to normal patients?
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pneumothorax - increased airway pressure, tracheal deviation, dilated neck veins
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How can you tell if an injury occurs by SSEP monitoring?
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P1 component increases in latency and decreases in amplitude
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What disturbs SSEP monitoring?
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1. hypoxia
2. hypercarbia 3. hypothermia, 4. hypotension, 5. drugs - diazepam, volatiles, N2O |
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What should you do if SSEP trace changes?
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stop surgery and raise blood pressure
-it may be due to stretching of the spinal cord, a bone chip, or direct cord trauma |
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Pertaining to SSEP monitoring what instrument rejects random waves and produces P1, N1, P2, N2?
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amplifier averager
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What is the cause of paralysis during harrington rod surgery?
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anterior spinal artery ischemia
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What are complications of harrington rod surgeries?
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1. paralysis,
2. hemorrhage, 3. fat and air embolism, 4. ptx |
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What hypotensive agent is preferrable for hypotensive anesthesia in adolescents and children?
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sodium nitroprusside for reliable and sustained induction of hypotension
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What is the benefit of using labetalol for inducing hypotension compared with SNP?
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effective
-not associated with some of the side effects such as tachycardia, intrapulmonary shunt or increased CO |
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what is a wake-up test?
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-after narcotic base is established, small increments of narcan are given until the patient responds to verbal commands and moves lower extremities
-assistant holds the head of ETT |
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What is the benefit of autologous blood for scoliosis surgery?
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minimizes the need for donor blood
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When should you begin collecting autologous blood before surgery?
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3 weeks before the operation with 4-7 days between collections to allow for readjustment of the blood volume
-don't collect within 7 days of surgery |
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How much blood is typically taken from patients for autologous donation base on their weight?
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->50kg and hgb 11 full units
-25-50kg and hgb 11 half units |
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What preop evaluation is important in pt with scoliosis?
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1. PFTs
2. ABGs - hypoxemia, hypercarbia, acidosis exacerbate pulm htn 3. CXR |
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What lines should be placed intraop?
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Foley, arterial, and CVP
-CVP reasonable to assess fluid status -If cor pulmonale is advanced, PA catheter is indicated |
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What is the postoperative course for pts with scoliosis?
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Ventilatory weaning postop should be slow and cautious
-if VC is <40%, postop ventilation is necessary |
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Does nitrous effect SSEP monitoring? Do volatiles?
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Yes, nitrous has a depressant effect on SSEPs
-Volatiles do as well -nitrous effects SSEPs more than low concentrations of enflurane and isoflurane |
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What 2 medications can decrease the total dose of SNP?
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1. propranolol
2. captopril |
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Explain the differences in sensitivity of brain stem responses vs cortical responses with SSEP monitoring.
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-Brain stem responses much more resistant to volatile anesthetic than are cortical responses
-Clinical concentrations tend to increase the latency of BAEP but do not have much effect upon amplitude |
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What are the physical characteristics of the scoliotic curve?
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-usually right sided curve
-involves 7-10 vertebrae |
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What happens to FEV1/FVC in restrictive lung disease?
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both FEV1 and FVC are decreased, but the percentage is not
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What is the major pulmonary defect in severe scoliosis? Explain breathing pattern.
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Alveolar hypoventilation secondary to V/Q mismatch
-typically rapid, shallow breathing develops bc of the restrictive nature of the dz leading to increased dead space -both A-a gradient and dead space are increased |
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Is hypercapnia seen in scoliosis?
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Usually only in very severe cases bc of the high solubility of CO2
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What neuropathic diseases can cause scoliosis?
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1. meningomyelocele
2. poliomyelitis 3. cerebral palsy 4. muscular dystrophy |
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Which scoliotics may be at an increased risk for malignant hyperthermia?
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Those with mytonic dystrophy
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