Week 3 Clinical Medicine: Shock, PAD, Pediatric Cardiology Flashcards
What are the 3 determinants of Stroke Volume (SV)?
Preload, Myocardial Contractility, Afterload
What is Shock and what is it caused by?
- inadequate tissue perfusion to meet metabolic demand and tissue oxygenation
causes: inadequate supply or increased demand (or both!)
What is the difference between Compensated, Decompensated, and Irreversible Shock?
Comp: reflex compensatory mechanisms activated to maintain perfusion to vital organs
- blood shunts CENTRAL; HR/contractility INC
- Sympathetic tone, catecholamines, RAAS INC
Decomp: tissue hypoperfusion and circulatory/metabolic derangement
- hypotension and lactic acidosis
Irreversible: organ/tissue injury SEVERE, correction CANNOT fix (survival impossible)
What is the difference between:
Cardiogenic Shock
Hypovolemic Shock
Distributive Shock
Obstructive Shock
What are they caused by?
C: BAD PUMP
- cardiomyopathy, Arrhythmias, Mechanical (ex: valves)
H: dec. intravascular volume
- hemorrhage or dehydration (non-hemorrhagic)
D: dec. SVR
- drugs or sepsis
O: mechanical obstruction of circulatory system
- ex: tension pneumothorax, pulmonary embolism
What is Cardiogenic Shock and what are its 3 subtypes?
What physiological changes are associated with it? (CO/SVR/CVP)
- “pump failure” = HEART is the PROBLEM
- CO dec. and SVR/CVP inc.
Subtypes:
- Cardiomyopathies (MC; ischemic, infect., drugs)
- Rhythm Problems (bradycardia/tachycardia)
- Valvular/Congenital (stenosis/VSD/etc)
Heart Muscle Problems (Cardiomyopathies) MOST COMMON CAUSE
What is Hypovolemic Shock and what are its 2 subtypes?
What physiological changes are associated with it? (CO/SVR/CVP)
- loss or lack of INTRAVASCULAR VOLUME
- CO/CVP dec. and SVP inc.
Subtypes:
- Hemorrhagic (blood loss)
- Non-hemorrhagic (fluid loss)
- dehydration (vomit, diarrhea, dec. intake)
- 3rd spacing (cirrhosis)
- through the skin (BURNS)
What is Distributive Shock and what are its 2 subtypes?
What physiological changes are associated with it? (CO/SVR/CVP)
- vasodilation of vascular beds causes dec. Systemic Vascular Resistance (SVR)
- SVP/CVP dec. and CO inc. (Neuro? = ALL decreased)
Subtypes:
- Septic (septic shock)
- Non-septic (neuro, anaphylactic, toxin/meds)
What is Obstructive Shock?
What physiological changes are associated with it? (CO/SVR/CVP)
What are 3 examples of this type of shock?
- mechanical obstruction within the cardiopulmonary system causing restriction of blood flowing into/out of heart
- dec. CO, inc. SVR, variable CVP
ex: tension pneumothroax, pericardial tamponade, pulmonary embolism
What is the goal of Shock treatment and what are 4 things that should be given to pts. suffering from shock? (F/V/US/A)
Goal: initial/rapid restoration of tissue hypo-perfusion and identifying the underlying cause
Tx: IV fluids, vasopressors, US evaluation (RUSH protocol to determine type), and broad spectrum antibiotics if infection thought to be cause (SEPSIS)
What are considerations when treating children and the elderly patients for possible shock?
Kids: hypotension not seen till too late
- will present with tachycardia and NORMAL BP
- work FAST to correct underlying tachycardia
Elderly: usually on cardiac medication
- may not see tachycardia (masked by meds)
- WORK UP
What are the screening guidelines for patients with Carotid Artery Stenosis?
- asymptomatic pts. should NOT be screened
- screening for pts with known atherosclerotic disease OR pts with carotid BRUITS using Carotid Duplex Ultrasound (tells us if stenosis is there, but not grade)
What are the screening procedures for patients suspected of Abdominal Aortic Aneurysm?
What pathology is seen on screening?
- abdominal ultrasonography as initial screen
- useful for 65-75 yo men (NOT women) who have a history of smoking
- see curvilinear calcifications outlining portions of aneurysm wall in 75% of pts.
What are the two treatment options for pts. with Aortic Aneurysm?
- Emergency Repair: endovascular repair has some improvement over open surgery
- bleeding hopefully confined to retroperitoneum
- open surgery: graft above and below aneurysm
- Elective Repair: indicated for aneurysms > 5.5 cm or those with rapid expansion (> 0.5 cm in 6 months)
What imaging is used to visualize an Abdominal Aortic Aneurysm?
CT scans or CT scans /contrast (can see vasculature)
- can also use US which is less risky (no contrast)
- can estimate size and see presence of aneurysm
Lower Extremity Arterial Disease
What is the most commonly affected artery due to atherosclerosis?
What testing can be done on these patients?
MC: superficial femoral artery
- common femoral and popliteal arteries also involved
- result in short-distance claudication (CALF PAIN)
Testing: Ankle-Brachial Indices
- no recommended for ASYMPTOMATIC pts.
- has excellent accuracy compared to angiography