Abdominal Aortic Aneurysms
Clinical Manifestations of Abdominal Aortic Aneurysm
Are often asymptomatic and frequently found during routine physical examinations or evaluations for an unrelated problem (e.g., abdominal x-ray, computed tomography [CT] scan). •A pulsatile mass in the periumbilical area slightly to the left of the midline may be present. •Bruits may be auscultated over the aneurysm. •Physical findings may be more difficult to detect in obese individuals. •AAA symptoms may mimic pain associated with abdominal or back disorders. •Compression of nearby anatomic structures and nerves may cause symptoms such as back pain, epigastric discomfort, and altered bowel elimination. •Occasionally, aneurysms spontaneously embolize plaque, causing "blue toe syndrome" (patchy mottling of the feet and toes in the presence of palpable pedal pulses).
Nursing Interventions After Surgical Repair of the Aorta
Circulatory Care: Arterial Insufficiency •Perform a comprehensive assessment of peripheral circulation (e.g., check peripheral pulses, edema, capillary refill, color, and temperature of extremities), to establish baseline status and detect altered peripheral perfusion. •Maintain adequate hydration to prevent increased blood viscosity. •Avoid applying direct heat to the extremity because burns can occur if numbness is present. •Administer antiplatelet or anticoagulant medications as appropriate to prevent thrombus formation. Neurologic Monitoring •Monitor vital signs: temperature, blood pressure, pulse, and respirations for changes in neurovascular status. •Monitor invasive hemodynamic parameters to identify changes from baseline. •Monitor for paresthesia: numbness and tingling as a sign of neurologic impairment. Hemodynamic Regulation •Monitor intake/output, urine output, and patient weight to detect signs of altered renal perfusion. •Monitor electrolyte levels to detect altered renal function. •Maintain fluid balance by administering IV fluids to ensure adequate hydration and renal perfusion. •Evaluate effects of fluid therapy to ensure adequate hydration. •Administer vasodilator and/or vasoconstrictor medication, as appropriate to maintain adequate renal artery pressure. Infection Protection •Monitor for systemic and localized signs and symptoms of infection (e.g., elevated body temperature; elevated white blood cell [WBC] count, heart rate, respiratory rate, decreased blood pressure, erythema and warmth along the incision line, persistent drainage from incision) to establish and detect changes in baseline status. •Monitor absolute granulocyte count, WBC count, and differential results, because increasing counts may be the first sign of infection. •Maintain asepsis for patient at risk, because incision sites and indwelling lines are potential portals for infection. •Maintain a closed system while doing invasive hemodynamic monitoring to prevent introduction of pathogens. •Instruct patient to take antibiotics as prescribed to maintain adequate blood levels of the drug. •Promote sufficient nutritional intake to promote healing.
Classification Aneurysm
Classified as true or false aneurysms. •A true aneurysm is one in which the wall of the artery forms the aneurysm, with at least one vessel layer still intact. True aneurysms are further subdivided into: •Fusiform aneurysm: is circumferential and relatively uniform in shape. •Saccular aneurysm: is pouch like with a narrow neck connecting the bulge to one side of the arterial wall. A false aneurysm, or pseudoaneurysm, is not an aneurysm but a disruption of all arterial wall layers with bleeding that is contained by surrounding anatomic structures. •False aneurysms may result from trauma, infection, peripheral artery bypass graft surgery (at the site of the graft-to-artery anastomosis), or arterial leakage after removal of cannulae (e.g., femoral artery catheters, intraaortic balloon pump devices).
Complications of Abdominal Aortic Aneurysm
Rupture of an aneurysm is the most serious complication. •If rupture occurs into the retroperitoneal space, bleeding may be controlled by surrounding anatomic structures, preventing exsanguination and death. •In this case the patient often has severe back pain and may or may not have back or flank ecchymosis (Grey Turner's sign). •If rupture occurs into the thoracic or abdominal cavity, more than 90% of patients will die from massive hemorrhage. •The patient who reaches the hospital will be in hypovolemic shock with tachycardia, hypotension, pale clammy skin, decreased urine output, altered level of consciousness, and abdominal tenderness. •In this situation, simultaneous resuscitation and immediate surgical repair are necessary.
AAA Risk Factors
The primary causes are classified as •Degenerative •Congenital •Mechanical (e.g., penetrating or blunt trauma) •Inflammatory (e.g., aortitis [Takayasu's arteritis]) •Infectious (e.g., aortitis [Chlamydia pneumoniae human immunodeficiency virus]). Risk factors for aortic aneurysms include: • Old age, male gender, family history • Hypertension •Coronary artery disease •High cholesterol •Lower extremity PAD •Carotid artery disease •Previous stroke •Tobacco use •Excess weight or obesity. •Male gender, older age, and tobacco use are the most important risk factors. •Whites and Native Americans have a higher risk of AAA development than African Americans, Hispanics, and Asian American
Aortic Aneurysms
• A permanent, localized outpouching or dilation of the vessel wall. •May involve the aortic arch and thoracic and/or abdominal aorta.
Nursing Management Aortic Aneurysms
•Begin by performing a thorough history and physical assessment. •Because atherosclerosis is a systemic disease, look for signs of coexisting cardiac, pulmonary, cerebral, and lower extremity vascular problems. Monitor the patient for signs of aneurysm rupture, such as: •Diaphoresis; pallor; weakness; tachycardia; hypotension; abdominal, back, groin, or periumbilical pain; changes in level of consciousness; or a pulsating abdominal mass. •Establishing baseline data is critical for comparison with later postoperative assessments. •Pay special attention to the character and quality of the patient's peripheral pulses, and renal and neurologic status. •Before surgery, mark pedal pulse sites (dorsalis pedis and posterior tibial) with a single-use marker and document any skin lesions on the lower extremities.
Abdominal Aortic Aneurysm
•Most occur below the renal arteries. •Abdominal aorta larger than 3 cm in diameter is considered aneurysmal. •Growth rates are unpredictable, but the larger the aneurysm, the greater the risk of rupture
Postoperative Management of Aneurysm Repair
•Patients typically go to an ICU for 24 to 48 hours for close monitoring. •When the patient arrives in the ICU, various devices are in place. •These include an endotracheal tube for mechanical ventilation, an arterial line, a central venous pressure (CVP) or pulmonary artery (PA) catheter, peripheral IV lines, an indwelling urinary catheter, and a nasogastric (NG) tube. •The patient needs continuous ECG and pulse oximetry monitoring. •If the thorax is opened during surgery, chest tubes will be in place. •Pain medication is given via epidural catheter or patient-controlled analgesia (PCA). •In addition to the usual goals of care for a postoperative patient (e.g., maintaining adequate respiratory function, fluid and electrolyte balance, and pain control) check for graft patency and renal perfusion. •Also watch for and intervene to limit or treat cardiac ischemia, dysrhythmias, infections, VTE, and neurologic complications.