Anesthetic Management of Aortic Aneurysm

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Anesthetic Management of Aortic Aneurysm

• Aortic dissection
• risk factors hypertension, aortic medial
  disease, Marfan syndrome, congential bicuspid
  aortic valves, aortic atherosclerosis, and blunt
  chest trauma

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• Aortic aneurysm
• classified by etiology, location, and shape
• most common dissecion
• predisposing atherosclerosis, aortitis, cystic
  medial necrosis, syphilitc aortitis, trauma,
  postoperative false aneurysm, connective tissue
  disorders, and congenital aortic anomalies
• De Bakey and Stanford classification
• Shape fusiform and saccular

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• Goal
• type and location of the lesion. one lung
  ventilation and distal perfusion
• prepare for blood loss
• monitor
• hemodynamic stability

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• Evaluation
• medial history, pevious chest X-ray,
  echocardiographic and angiographic stuides
• prior lung status
• control of BP and ejection velocity combine beta
  blockers and vasodilators

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• Premeditation
• Elective beta blockers, calcium channel
  blockers, diuretics, ACEI
• anxiolytic agent (sedative) lorazepam 1-2mg PO,
  midazolam 1-4mg iv and morphine 0.05-0.1mg/kg im
• Emergency
• beta-blocking agents esmolol, metoprolol, or
  propranolo
• vasodilators nitroprusside, nitroglycerin,
  trimethaphan

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• Preinduction
• big iv cathether
• A-line
• femeral a-line
• pressor and vasodilator agents
• 6 units blood
• antithrombolytic agent (aminocaproic acid or
  aprotinin)
• epidural catheters

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• Induction
• non-emergent procedure
• fentanyl (50-100ug/kg) or sufentanyl (10-12
  ug/kg)
• intermediate-acting, non-depolarizing
  neuromuscular blocker vecuronium (0.1mg/kg),
  rocurinium(0.6mg/kg), or cis-atracurium
  (0.2mg/kg)
• no pancuronium

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• Emergent procedure
• rapid sequence induction
• thiopental , propofol,or etomidate in combination
  with small dose narcotics
• SCC, beta-blocker and vasodilator before
  laryngoscopy
• --single , double lumen, univent

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• Intra-operative management
• additional venous access
• V5 lead, a-line, PA catheter
• bleeding and coagulopathy

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• PWCP increase with cross-clamp application
• A. LV afterload mismatch with LV dilation
• B. myocardial ischemia
• C.impaired LV diastolic function due to impaired
  relaxtion

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• Acidosis
• sod. bicarbonate continuous infusion
  (0.05mEq/kg/min)during cross-clamping

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• cross clamp removal hypotension , pulmonary
  hypertension, and metabolic acidosis
• shunt and left heart bypass, partial CPB
• (distal 40-60mmhg)

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• Acid-base status,
• renal functuin,
• short cross-clamp time

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Awake Aortic Aneurysm Repair in Patients with
Severe Pulmonary Disease

• McGregor Am J Surg, Volume
  178(2).August 1999.121-124
• BACKGROUND We report the use of retroperitoneal
  aortic aneurysm repair utilizing exclusive
  regional anesthesia (no intubation or inhalation
  anesthetic) in high pulmonary risk patients.

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• METHODS Six patients were retrospectively
  reviewed. Pulmonary disease was diagnosed by
  clinical history and pulmonary function tests.
  Patients received intravenous sedation and
  regional anesthesia. Retroperitoneal aortoiliac
  aneurysm repair was performed.

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• Regional Anesthesia.
• Patients upright, exaggerated kyphotic position
  17-gauge epidural needle L2-3 or L3-4 interspace,
  
• test dose 3cc lidocaine 1.5 and epinephrine
  1200,000
• A 25-gauge Whitticre needle Spinal anesthesia
  with bupivicaine 0.5 (6 to 7 mg) and fentanyl
  (25 to 30 mcg),
• epidural catheter 3 to 4 cm. A T7-8 sensory
  block was required to start the procedure
• Inadequate bupivicaine 0.5 (10 cc) and fentanyl
  50 to 100 mcg in incremental doses.
• During aortic dissection and cross-clamping,
  anesthesia was raised to the T5 level.
• morphine (3 to 4 mg) for postoperative pain
  control.

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• RESULTS a population with several comorbidities.
  Patient age was 72 /- 4 years, and concurrent
  illnesses included coronary artery disease,
  cerebrovascular disease, and obesity. Cardiac
  ejection fraction was 46 /- 11. Smoking
  history was 62 /- 2 pack-years. All patients
  used inhaled steroids and albuterol, and 3
  required theophylline and home oxygen
• therapy.
• PFT severe pulmonary disease
• FEV1 0.85 /- 0.1 L (23 /- 5 of predicted),
  FVC 1.64 /- 0.2 L (34 /- 5 of
• predicted), and PO2 62 /- 2 mm Hg.

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• The authors felt that the more recent use of
  supplemental epidural anesthesia was partially
  responsible for improved outcome. Epidural
  anesthesia offers many benefits, including
  inhibition of the surgical stress response,
  decrease in myocardial oxygen demand, fewer
  pulmonary complications, improved renal cortical
  blood flow, and better postoperative pain
  control.

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• The improvement in pulmonary status is related to
  a smaller decrease in FVC and FEV1, less alveolar
  shunting, and fewer pulmonary infections.
• Adverse effects of general anesthesia such as
  myocardial and respiratory depression
• pulmonary function values of less than 50 of
  predicted are a relative contraindication to
  elective aortic reconstruction. However, because
  of the limited pulmonary sequelae seen using
  retroperitoneal repair with exclusive epidural
  anesthesia, patients with severely compromised
  pulmonary function may be able to undergo
  elective surgery.

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• Several aspects of this study merit further
  discussion.
• First, both spinal and epidural anesthesia were
  utilized better muscle relaxation and lower total
  doses of anesthetic and narcotic medications are
  needed.
• Second, inhalation anesthetic was avoided by
  maintaining patients at ideal level of
  sedation.kept alert enough to protect their
  airways and answer questions, but sedated enough
  to control anxiety and agitation.

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• Third, thorough communication among surgeon,
  anesthesiologist, and patient is critical.
  Reassuring patients on their progress and keeping
  a calm operating room environment facilitates
  patient tolerance and success with this
  procedure.
• Finally, this is a technically demanding
  procedure with anatomic limitations that need to
  be considered during patient selection. These
  include limited access to the right renal artery,
  inability to detect synchronous intraperitoneal
  pathology, and long-term wound complications.
• Performing this procedure on patients more likely
  to be receiving systemic steroid therapy may
  particularly predispose to wound complications.
  Therefore, strict adherence to sterile technique
  and careful tissue handling are essential.

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• CONCLUSIONS
• Results from this study suggest that patients
  with severe pulmonary disease can undergo
  elective abdominal aortic aneurysm repair under
  exclusive regional anesthesia safely and without
  pulmonary morbidity. Patient selection, and
  experienced anesthesiologist, and communication
  with the patient are critical to the success of
  this procedure. Retroperitoneal aortic repair
  with exclusive regional anesthesia should be
  considered in high pulmonary risk patients.