Aortic Disease

Front 1

AORTIC DISSECTION

Back 1

-involves the longitudinal separation of the medial layers of the aorta by a column of blood
-the dissection begins at a tear in the aortic wall
-blood under the force of arterial pressure goes through the intimal tear and enters the media of the aorta and splits (dissects) the aortic wall
-blood pumped through this tear creates a false channel, or lumen
-a dissection does not result from a weakening and ballooning out of a vascular wall
-caused by arterial HTN, unlike aortic aneurysm which is caused by arteriosclerosis
-over time the systolic pressure associated with systemic arterial HTN allows for a dissection between the intima and media layers
-most commonly originate in the thoracic aorta

Front 2

AORTIC DISSECTION cont

Back 2

-if the dissection extends proximally, it may involve the aortic valve rendering it incompetent
-as the dissection progresses forward, it may result in disruption of the arteries that originate off the arch and proximal ascending aorta
-pt will have sudden intense chest pain, described as burning or tearing
-look for the murmur of aortic regurgitation or alterations of the peripheral pulses
-x-ray may show a widened mediastinum
-cardiac ischemia may be present if the dissection involves the coronary arteries
-cardiac tamponade may be another complication if dissection involves the aortic root
-neurological deficits may occur if the aortic arch vessels are involved
-dissections involving the renal arteries result in elevated serum creatinine, dec u/o, and severe HTN difficult to manage

Front 3

Aortic Dissection Management

Back 3

-therapy is geared at decreasing the forces that favor progression of the dissection
-a BB is used in conjunction with sodium nitroprusside to dec cardiac contractility and heart rate
-The prime consideration in the medical management of aortic dissection is strict blood pressure control
-Another factor is to reduce the shear-force dP/dt (force of ejection of blood from the left ventricle
-To reduce the shear stress, a vasodilator such as sodium nitroprusside should be used with a beta blocker, such as esmolol, propranolol, or labetalol

Front 4

Air Care protocol

Back 4

-At time of dispatch request 2 units of 0 negative or type specific PRBC
-Document pulses in all four ext
-Administer fentanyl and versed for pain, anxiety, sedation
-The optimum MAP is 60-80, Treat the higher pressure
-Treat HTN and HR with Esmolol
-If MAP is >80 an HR is >60 and analgesia/sedation have been addressed, and Esmolol is maxed out (300mcg/kg/min, or if HR drops <60 and MAP is still elevated, add Sodium Nitroprusside

Esmolol:
-a beta1-selective (cardioselective) adrenergic receptor blocking agent (beta blocker)
-activation of beta1 receptors in the SA node by norepi results in depolarization of the SA node and inc HR and contraction
-esmolol slows down HR and dec contraction

-mix 2.5g in 250ml D5W, initiate at 50mcg/kg/min q 5min
-increase at: 50, 100, 200, 300mcg/kg/min
-end point is max dose 300mcg/kg/min, HR<60 or MAP <80

Sodium Nitroprusside:
-Acts on vascular smooth muscle to reduce afterload
-Mix 50mg in 250ml D5W
-Initiate at 0.2mcg/kg/min, titrate 0.1mcg/kg/min
-Titrate at 1mcg/kg/min once 1mcg is reached
-Max dose is 10mcg/kg/min

Front 5

Debakey classification

Back 5

-Is an anatomical description of the aortic dissection
-It categorizes the dissection based on where the original intimal tear is located and the extent of the dissection (localized to either the ascending aorta or descending aorta, or involves both the ascending and descending aorta
-Type I - Originates in ascending aorta, propagates at least to the aortic arch and often beyond it distally.
-Type II – Originates in and is confined to the ascending aorta.
-Type III – Originates in descending aorta, rarely extends proximally

Front 6

AORTIC ANEURYSM

Back 6

-a localized dilation of the aorta to a size greater than 1.5 times its normal diameter
-involves all three layers, intima, media, adventitia
-weakening of all three layers
-arteriosclerotic in origin
-frequently HTN is present, with hx of smoking
-may be thoracic or abdominal
-an infrarenal aortic diameter of 3cm or greater can be defined as abd aortic aneurysm AAA
-an aneurysm does not have a false passage
-symptoms are usually related to expansion or rupture of the aneurysm
-surgical repair is indicated in aneurysms larger than 5cm
-abd pulsations, back pain, throbbing or colicky pain, oliguria

Front 7

Aortic Aneurysm Management

Back 7

-is dependent on on the pt hemodynamic stability
-crystalloid is the most immediate supportive measure
-definitive treatment is surgical intervention