Hemodynamic Instability Flashcards
What causes AAA?
Degeneration of collagen fibres and elastin, loss of smooth muscle fibres which results in thinning of medial layer and dilation of affected area
What is AAA?
Full thickness dilation of a BV that is greater that 50% the normal aortic diameter
What is the normal diameter of the aorta? If the aorta is considered aneurysmal, what does the diameter have to be?
2 cm. >3cm.
What are other locations for aortic aneurysms? What is the most common?
Ascending thoracic aorta, descending thoracic aorta, and abdominal aorta (most common).
What are the manifestations of a symptomatic AAA?
Abdominal, back, flank pain. N/V if pressing on adjacent bowel, back pain from pressure on spinal nerves or ischemia from embolization to distal circulation (lower limbs, gut, kidneys)
What is the triad of symptoms for AAA rupture?
Severe acute abdominal/back pain, profound decreased BP, pulsatile abdominal mass.
What is the most useful predictor of repairs for AAA?
AAA greater than or equal to 5.5 cm
When would someone get an open repair versus an EVAR?
Open repair if ruptured, EVAR for high risk patients
What are some common post-op complications from open repair of AAA?
Spinal ischemia and neuro deficits (from prolonged cross-clamp time), Fluid imbalances, embolization of thrombus or debris from inside of aneurysm to distal sites including circulation to lower limbs, gut, kidneys. Most common are bowel ischemia and AKI (prolonged cross clamp time).
What are nursing priorities caring for someone post AAA repair?
Control BP, close hemodynamic monitoring, assess distal circulation, check incision site, may have difficulty ventilating patient due to distended abdomen/pain
What is the definition of shock?
Hemodynamic instability and impaired widespread EOP that goes untreated
What is the predominant issue in hypovolemic shock? How are other determinants of CO affected?
Decreased preload. Increased after load (SNS comp mech), decreased contractility (decreased preload), increased HR (SNS comp mech), decreased CO overall.
What is the main treatment for hypovolemic shock? How will it help?
Fluid resuscitation (will help preload). Afterload, contractility and HR should all improve once CO is restored.
What is the main issue in cardiogenic shock? How are other determinants of CO affected?
Contractility is poor. Preload is increased (blood backing up as it isn’t pumping forward), after load is increased (comp mech from decreased CO and poor perfusion, SNS and RAAS), increased HR (SNS), decreased CO overall.
What is the main treatment for cardiogenic shock? How will it help?
Nitro or diuretic to decrease preload, + inotrope to support contractility, and nitro or vasodilator to support after load.
What is the main issue in distributive shock? How are other determinants of CO affected?
Reduced afterload is the primary problem (PNS>SNS, sepsis), preload is decreased (due to decreased venous return), contractility is decreased (due to decreased preload), HR is increased (due to SNS). Initially CO may be increased or normal due to decreased after load (less force to pump against) but will eventually decrease.