Hypotension Flashcards
what is considered hypotension
<90/60
treat the patient not the number! consider what is normal for the patient
what is the pathophysiology of hypotension
- Hypotension reduces blood flow
- Decreasing oxygen delivery to organs and tissues
- Causing cellular damage and dysfunction.
what is circulatory shock
when oxygen delivery is insufficient to support tissue metabolic requirements
what three factors determine arterial pressure
1)cardiac output
2)venous pressure
3)systemic vascular resistance
any reduction in these variables can lead to hypotension
what are possible causes of hypotension
- arrhythmias
- structural disease (HF, valve disease)
- hypovolemia
- systemic vasodilation (sepsis, anaphylaxis)
- obstructive (PE)
- endocrine (hypothyroid, adrenal insufficiency)
- drug induced
(by the end of this course youll be able to intuitively know these)
what are the 5 history questions to ask a patient with hypotension
- Acute change in BP?
- Precipitating events/symptoms?
- Medications, including any recent changes?
- Pre-existing medical conditions?
- Are they symptomatic?
what are symptoms of hypotension
- Lightheadedness, dizziness
- Syncope
- Nausea
- Confusion
- Fatigue
Depends on the patient, underlying cause, existing comorbidities, age, etc.
what are the signs of hypotension
- bradycardia/tachycardia
- pallor, diaphoresis, cool/clammy, prolonged cap refill
- Altered LOC
- other signs depend on underlying mechanism
what is diagnostic testing for hypotension
- EKG
- CBC, CMP, UA
- Echo
- UDS
- CT head
note: testing should reflect your diagnosis
what is the management used for the majority of hypotensive patients? Who would we NOT want to treat this way?
IV bolus of normal saline
Careful in patients with heart failure due to fluid overload
what is orthostatic hypotension
a drop in BP upon standing, leading to symptoms of hypotension.
what are causes of orthostatic hypotension
- impairment of autonomic reflexes
- volume depletion
what is the criteria for orthostatic hypotension
A 20 mmHg fall in SBP
OR
A 10 mmHg fall in DBP
after standing from a lying position
how long after standing does orthostatic hypotension typically occur
within 2-5 minutes of standing (delayed orthostasis may occur after 5 or even 10 minutes)
What is the normal BP response to standing
rapid decrease in venous return and cardiac output which causes stimulation of the SNS
1. increase in HR
2. increase in PVR
3. therefore increasing CO and limiting
What detects change in position of the body (such as from lying to standing up)
baroreceptors in the carotids
what are things could lead to orthostatic hypotension
- Prolonged lying or sitting
- Volume depletion
- Autonomic failure
- Neurodegenerative disease, such as Parkinson’s
- Neuropathies, as a result of DM, B12 deficiency, amyloidosis, sarcoidosis, Lyme disease
- Medication SE
what medication classess can cause orthostatic hypotension
what are the classic symptoms for orthostatic hypotension
Generalized weakness
Dizziness or lightheadedness
Blurry vision or darkening of the visual fields
Syncope
what are atypical presentations of orthostatic hypotension
fatigue
cognitive slowing
nausea
what are the diagnostic studies that can be done to evaluate for orthostatic hypotension
bedside tilt test
formal tilt table test
what is bedside tilt test or orthostatic BP measurement
have patient lie down for 5 minutes , then sit up for 2 minutes, then stand and take BP immediatly after standing, then at 2 minutes, then at 5 minutes.
describe tilt table testing
- pt lies down and is strapped into bed
- IV in for PRN fluids
- ECG and BP are monitored
- pt lies flat then raised to standing angle.
- note symptoms for the next 45 mintues
- if no symptoms, lie flat and give meds to increase HR
- tilt patient upright and monitor for symptoms
- lower flat and get back to baseline. once normal, test is complete
how many patients have no identifiable cause of orthostatic hypotension
1/3
what tests should be don after tilt testing to focus on treatable conditions
CBC
CMP
EKG
EMG
how do you treat acute orthostasis d/t volume depletion
IV fluids
how do you treat chronic orthostasis
symptoms are managed initially with nonpharmacologic measures, which the patient must strictly adhere to
pharm therapy is added if there are severe symtpms or symptoms refractory to nonpharm therapy
what are options for nonpharm management of chronic orthostasis
- rmeove causative medication if possible
- lifestyle modifications
- physical maneuvers
what are the lifestyle modifications used to treat orthostasis
- Get up slowly
- Straining, coughing and exertion in hot weather can exacerbate sx’s
- Elastic compression stockings
- 6 to 10 g of sodium per day
- At least 3 liters of water a day
what are the physical maneuvers used to treat orthostasis
- Tensing leg muscles while standing; crossing legs tightly while standing
- Isometric handgrip when standing
what are the medications used to treat orthostasis
Fludrocortisone (Florinef)
Midodrine (ProAmatine)
not first line. only used if symptoms are severe or if pt is refractory to non-pharm treatment
What should be watched for closely in a patient who is using pharmacologic measures to manage orthostatic hypotension
- supine HTN!!
- have pts monitor BP mulitple times/day while sitting/standing and lying
- elevate head of bed 20-30 degrees while sleeping to protect brain from supine HTN
what drug class is fludrocortisone
Potent mineralocorticoid with high glucocorticoid activity
what is the MOA of fludrocortisone
Promotes increased sodium reabsorption and potassium excretion from renal distal tubules
what is the Dosage of fludrocortisone
Initiated at 0.1mg/day and may be increased in weekly increments to 0.3mg/day
what are possible SE of fludrocortisone
edema
supine/sitting HTN
what is the possible electrolyte abnormality with fludrocortisone use?
hypokalemia
what lab study should be done after starting a patient on fludrocortisone
BMP after a week
what drug class is midodrine
Alpha-1 selective adrenergic agonist
what is the MOA of midodrine
Increases peripheral vascular resistance, which increases arteriolar and venous tone, resulting in increased SBP and DBP
Does not cross the blood-brain barrier
why is fludrocortisone usually used over midorine
midodrine has a short half life and therefore must be dosed TID
what is the dosage of midodrine
Initiate dose of 2.5mg TID, then titrate weekly to 10mg TID for desired response
what are the SE of midodrine
supine HT
paresthesias
piloerection
pruritus
GI upset
urinary retention or urgency.
what is the usual cause of discontinuation of midodrine
Supine HTN
what is POTS
Another form of orthostatic intolerance, but the hallmark response to standing is an exaggerated increase in heart rate
what is the common demographic for POTS
young female patients (14-45)
what is the possible etiology of POTS
Distal denervation
Hypovolemia
Venous dysfunction
Cardiovascular deconditioning
Baroreflex abnormalities
Increased sympathetic activity
Genetic abnormalities
what is the clinical presentation of POTS
Dizziness / Lightheadedness
Syncope
Weakness and fatigue
Blurry vision
what is diagnostic criteria for pots
●History of symptoms of orthostatic intolerance
●Correlation of symptoms with a sustained increase in upright heart rate by at least 30 beats/minute (40 beats/minute for patients under the age of 20 years) within 10 minutes of standing or head-up tilt, without orthostatic hypotension
●Autonomic testing to correlate symptoms with heart rate changes, confirm the diagnosis, and assess the degree of objective signs of orthostatic intolerance
●Other diagnostic testing as needed to exclude alternative diagnoses or confounding concomitant conditions
what is the gold standard for POTS diagnosis? what is considered a positive test?
formal tilt table test
Must see a sustained increase in HR of greater than 30 bpm OR
An increase to 120 bpm or higher in the first 10 minutes of the test
There should be no drop in blood pressure
what should INITIAL evaluation of POTS include
CBC
CMP
EKG
TFTs
what is nonpharmacological treatment for POTS
- Avoid any exacerbating factors
- Increase water intake (2 liters per day)
- Increase salt intake (3 to 5 grams per day)
- Aerobic exercise of the lower extremities / compression stockings
what is pharmacologic treatment for POTS
Fludrocortisone
Midodrine
Beta blockers, such as Propranolol (20 to 30 mg tid or qid)
SSRI/SNRI – rarely used but have been shown to be beneficial in some
what is the survival rate of cardiogennic shock
50%
what is the definition of cardiogenic shock
Result of the failure of the heart in its function as a pump, resulting in inadequate cardiac output.
what is the MCC of cardiogenic shock
- Extensive myocardial damage from an acute MI
- Mechanical complications of an acute MI (such as valve lesions, arrhythmias, cardiomyopathies)
what are the causes of cardiogenic shock
what is the principle feature of cardiogenic shock
hypotension with evidence of end-organ hypoperfusion
(occurs as consequence of inadequate cardiac function)
what is the classic presetation of cardiogenic shock
peripheral vasoconstriction (cool, moist skin)
tachycardia
what are lab findings in patients with recent or acute MIs
elevations in cardiac-specific enzymes (CK-MB, troponin)
what are lab findings in pateitns with renal and hepatic hypoperfusion
elevations in serum ceratinine and AST, ALT
what are lab findings in pateints with hepatic congestion or hepatic hypoperfusion
Coagulation abnormalities may be present. An anion gap acidosis may be present, and the serum lactate level may be elevated.
“youll go more into this later in the semester but i just wanted you to know the overview”
