Shock/Hypotension Flashcards
What is shock?
Circulatory failure
What is the cellular mechanism of shock?
- Inadequate O2 delivery or utilization or too much consumption
- Cellular/tissue hypoxia
- cell membrane ion pump dysfunction -> intracellular edema -. leakage to extracellular -> inadequate regulation of pH
- systemic acidosis, endothelial dysfunction, inflammatory cascade -> ant-inflammatory cascade
- Decreased tissue perfusion
What are the four key types of shock?
Distributive
Cardiogenic
Hypovolemic
Obstructive
(plus Combination)
Which forms of shock are primarily
due to decreased systemic vascular resistance?
Distributive Shock
Which forms of shock are primarily due to
decreased cardiac output?
Cardiogenic
(late) Hypovolemic
(late) Obstrucitve
What can cause shock (decreased perfusion) but with normal cardiac output and normal systemic vascular resistance ?
Carbon monoxide poisoning
Cyanide poisoning
Mitochondrial disease
What are the three stages of shock and what are they symptoms of each?
Pre-shock aka Compensated Shock aka Cryptic Shock:
SX: tachycardia, cool skin, hypotension
Shock: compensatory mechanisms inadequate
SX: tachycardia, dyspnea, restlessness, diaphoresis, N/V, thirst, pallor, narrow pulse pressure, decreased mental status, hypotension, oliguria, cool clammy skin
Decompensated Shock aka End Organ Dysfunction
SX: hypotension, anuria, labored irregular breathing, thready, weak or absent peripheral pulses, ashy/cyanotic skin, decreased body temp and mental status, dilated pupils
A patient has an infection and then develops signs and Sx of shock. What is the likely type of shock?
Septic
which is a kind of distributive shock
A patient suffering from severe aortic stenosis develops signs/Sx of shock. What type of shock is likely?
Mechanical Cardiogenic
A patient with the flu who has severe N/V/D for several days followed by shock Sx. Which is the likely type of shock?
Non-Hemorrhagic Hypovolemic
A patient develops trouble breathing after a long flight from Kenya, and then develops Sx of shock. Which type is likely?
Pulmonary Vascular Obstructive Shock
(from a PE)
What type of shock is anaphylaxis?
Non-septic distributive shock
A patient has complete heart block and develops shock Sx. Which kind?
Arrhythmogenic Cardiogenic shock
A patient is in a car accident and develops pericardial tamonade and Sx of shock. Which kind?
Mechanical Obstructive
What is the pathophysiology of cardiogenic shock
caused by an MI as pertains to Systolic and Diastolic function?
Systolic:
- Decreased cardiac output and stroke volume -> hypotension -> decreased coronary perfusion -> ischemia -> progressive myocardial dysfunction -> Death
- Decreased cardiac output and stroke volume -> decreasesd systemic perfusion -> compensatory vasoconstriction -> progressive myocardial dysfunction
Diastolic:
- Increased LVEDP and pulmonary congestion -> hypoxemia -> ischemia -> progressive myocardial dysfunction -> Death
How do you work up a patient with shock?
- Cover your ABCs: airway, breathing, circulation
- Determine the underlying cause (may need tests)
- Initiate life-saving maneuvers re underlying cause (Chest tube for tension pneumothorax, Epinephrine for anaphylaxis, IV antibiotics for sepsis, coronary revascularization for MI, steriods for adrenal crisis)
- Once stable do focussed Hx and PE, general and targetted lab studies, plus possible Echo and pulmonary artery catheterization for definitive Dx and Tx
- Treat the cause (eg: steriods for adrenal crisis, IV ABX for sepsis)
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- Treat the cause (eg: steriods for adrenal crisis, IV ABX for sepsis)
What are some causes of cardiogenic shock?
Ischemia or MI
LV failure
Ventricular Septal Rupture
Papillary m or chordea t. rupture re severe mitral regurg
ventricular free wall rupture
How to you treat cardiogenic shock?
- General: ventilation, IV fluids, sodium bicarb re acidosis, aspirin, IV heparin, possible glycoprotein IIb/IIIa Inhib, possible insertion of pulmonary artery catheter
-
Specific:
- Meds: sympathomimetic inotropes, Norepi
- Revascularization: PCI, CABG, thrombolytics
- Mechanical: intra-aortic balloon pump, left ventricular or biventricular assist device, percutaneous cardiopulmonary bypass
What is the 30-day survival rate for patients with cardiogenic shock?
about 50%
What are the Sx and ETX of orthostatic hypotension?
Sx: dizziness, blurred vision, weakness, syncope, confusion, nausea upon standing
ETX:
Acute: dehydration, prolonged bedrest, hypoglycemia, overheated, post-prandial
Chronic: heart problems (rate, valve, HF), endocrine (DM, thryroid, adrenal), regulation problems (neuro or baroreceptor)
How do you diagnose and treat orthostatic hypotension?
Dx: Orthostatic blood pressure testing, blood tests re anemia, hypoglycemia, EKG/Holter, Echo re structure, ETT, Tilt Table, Valsalva maneuver
Tx: depends on cause
- Lifestyle changes: hydration, less alcohol, more salt, elevate head of bed
- Compressive stockings
- Medications: fludrocortisone, midodrine
What is cardiogenic syncope?
Sudden drop in heart rate and BP causing fainting causes by cardiac arrhythmia or structural heart problem
What are the Sx of cardiogenic syncope
Fainting plus possibly:
Chest tightness
SOB
Sweating
Apprehension
Palpiation
Who is likely to get cardiogenic syncope?
Older patients with heart disease
How do you diagnose and treat cardiogenic syncope?
Dx: EKG, Holter or Event Recorder and possible electrophysioligy testing
Tx: depends on cause:
Bradycardia: pacemaker
Tachycardia: meds, ablation, implanted defribrillator
