Lecture 3: Hypotension Flashcards
What typically is referred to as hypotension?
< 90/60
Always treat the patient, not the number.
What is the main concern with regards to hypotension?
Hypoperfusion of organs, causing cellular damage.
What 3 things determine arterial BP?
- CO
- Venous pressure
- SVR
What general etiologies typically result in hypotension?
- Cardiogenic shock
- Hypovolemia
- Orthostatic Hypotension
- Sepsis/septic shock
- Endocrinology
- Vascular changes
- Drug-induced
- Neurogenic shock
What skin signs are typical of someone with hypotension?
- Cool
- Clammy
- Diaphoretic
- Pallor
- Delayed cap refill
What is the general treatment for a hypotensive patient? What etiology would not use the general treatment?
Fluid resuscitation via IV NS bolus.
However, we should avoid fluids in people in HF.
Define orthostatic hypotension/postural hypotension.
Drop in BP upon standing, leading to actual symptoms of hypotension.
- 20 mm SBP drop
- 10 mm DBP drop
Change from standing to lying.
Due to either autonomic reflex dysfunction or volume depletion in general.
What happens to venous return and CO upon standing?
Decreases in both.
How does our body typically prevent orthostatic hypotension?
- Increased HR
- Increased SVR
- Results in increased CO to prevent SBP drop
Sympathetic stimulation
What are the classic symptoms of orthostatic hypotension?
- Generalized weakness
- Dizziness or lightheadedness
- Blurry vision or darkening of visual fields
- Syncope
Should only occur when changing positions to standing.
What are the atypical symptoms of orthostatic hypotension?
- Fatigue
- Cognitive slowing
- Nausea
What are the two typical evaluation methods for orthostatic hypotension?
- Bedside tilt test/orthostatic BP measurement
- Formal tilt table test
Describe a tilt table test and the medications typically used.
- Strapped to a table, start laying flat then standing for 45 mins.
- If no response, NTG is administered while flat again.
- Tilted upright again to test for symptoms.
What is the primary cause of acute orthostasis?
Volume depletion, treated via IV fluids.
What two medications have evidence for use in orthostasis?
- Fludrocortisone
- Midodrine
What is a common complication of treating orthostasis with medication?
Supine hypertension
What class is fludrocortisone and its MOA?
It is a mineralcorticoid with high glucocorticoid activity.
It promotes potassium excretion and sodium reabsorption.
Preferred over midodrine
What are the main SEs of fludrocortisone?
- Edema
- Hypokalemia
- Supine/sitting HTN
What class is midodrine and its MOA?
It is an a1 selective adrenergic agonist.
Increases SVR, increasing SBP and DBP without crossing BBB.
Main consideration: short half-life, requiring TID.
What is POTS?
Postural orthostatic tachycardia syndrome
A variation of orthostasis primarily characterized by tachycardia.
What is the diagnostic criteria for POTS?
- Hx of orthostatic symptoms w or w/o systemic symptoms.
- Sustained increase in HR by at least 30bpm (40 for pts < 20yo) within 10 minutes without orthostatic hypotension.
- Autonomic testing to confirm.
What is the gold standard test to diagnose POTS?
Formal tilt table test showing 30 BPM increase or > 120 BPM within 10 mins WITHOUT hypotension.
What are nonpharmacological treatments for POTS?
- Avoid exacerbating factors
- Drink more water (2-3L)
- Eat more salt (3-5g)
- Exercise + compression stockings.
What medications are used for POTS?
- Fludrocortisone
- Midodrine
- BBs (Propranolol)
- SSRI/SNRI (rarely used)
What is the prognosis for POTS?
Good. People generally grow out of it within 1-2 years.
What are the 4 types of shock?
- Distributive
- Cardiogenic
- Hypovolemic
- Obstructive
What characterizes cardiogenic shock and the MCC?
Inability of the heart to pump properly, resulting in inadequate CO.
MCC: acute MI and its complications.
What defines shock?
Hypotension with evidence of end-organ hypoperfusion.
What is the classic presentation of a patient with cardiogenic shock?
- Peripheral vasoconstriction (cool, moist skin)
- Tachycardia
For a patient presenting with cardiogenic shock, what would suggest recent or acute MI?
Cardiac enzyme elevation (trop, CK-MB)
For a patient presenting with cardiogenic shock, what would suggest renal and hepatic hypoperfusion?
- Elevated serum creatinine
- Elevated AST and ALT
For a patient with cardiogenic shock, what would suggest hepatic congestion or hypoperfusion?
- Coagulation abnormalities
- Anion gap acidosis
- Serum Lactate
