7- intraoperative Hypotension/ hypertension Flashcards
What are the type of adrenergic receptors and where are they found?
Alpha-1 works (ONE)
O-blOOd Vessels, N-Neck/ bladder, E-Eye
Alpha-2
Presynaptic Nerve terminal
Beta-1
Heart
Beta-2
Lungs
More on Alpha-1?
Vasoconstricts
GI relaxation
More on Alpha-2?
Vasoconstricts
Decreased insulin secretion
Platelet aggregation
more on Beta-1?
Increased HR
AV conduction
Contractility of heart
Increased renin secretion
more on beta-2?
Bronchial relaxation, relaxation of vascular smooth muscle
Dopamine-1 ?
Vasodilation
Increased renin release
Dopamine-2?
Inhibits NE release
May constrict renal and mesenteric smooth muscles
What does systolic mean?
The force of blood against artery walls when the ventricles contract
What does diastolic mean?
The pressure in the arteries when the ventricles relax
What does MAP mean?
1/3 Systolic + 2/3 Diastolic = MAP
What does pulse pressure mean?
Difference between systolic and diastolic
How to calculate cardiac output?
CO= HR X SV
True/ False:
SV in kids doesn’t change while it does in adults
True
In infants SV is fixed so CO is HR dependent.
In adults, SV plays a much more important role when increasing HR
What does SV depend on?
1-Preload
2-Afrerload
3-Contractility
What does Preload entail?
Left ventricular (LV) end-diastolic volumes
LVEDV
What does Afterload entail?
Resistance to ejection of blood from
LV (SVR = 80(MAP-CVP)/CO)
SVR=Systemic vascular resistance
MAP= mean arterial pressure
CVP= Central venous pressure
CO= cardiac output
what does contractility entail?
Force and velocity of ventricular contraction
Intra-op Hypotension - Causes?
-Hypovolemia - Dehydration, inadequate IV intake,
fever, diarrhea
-Functional Hypovolemia - Sepsis (Decrease SVR,
Increase venous
capacitance), Cardiac failure, Hemorrhage,
Neurogenic loss, Anaphylaxis
-Drugs - Induction agents, volatile anesthetics,
histamine-releasing meds,
regional anesthetics
-Positive pressure ventilation
-Cardiac tamponade, tension pneumothorax
-Autonomic neuropathy - DM I, II, Guillain-Barre sx,
spinal cord injuries, HIV,
orthostatic hypotension
What drugs are used during hypotension ?
Adrenergic Agonists buy time to make a true diagnosis
Phenylephrine, Ephedrine, Epinephrine, NE, Dopamine
Decrease anesthesia
True/ false
Giving fluids will help with hypotension ?
True
What signs can be used to diagnose hypotension?
-HR, BP, Urine output, hematocrit, base deficit, serum
lactate, response to fluid bolus, central venous
pressure, cardiac output monitor, stroke
volume variation, pulse pressure variation,
respiratory variation of the a-line tracing, physical exam (i.e. dry mucous membranes)
-“Goal Directed Therapy”
Remember ABC, ABC?
Airway, Breathing, Circulation, Anesthesia, Body positioning, Celsius
Hypertension blood pressure categories?
Intra-op Hypertension - Causes?
What are the unknown cause?
-Essential HTN - unknown cause; >90% of HTN
patients
-PAIN
-Wrong cuff size
Intra-op Hypertension - Causes?
What are the known cause?
Secondary HTN (known cause):
-Endocrine - Cushing’s dx, pheochromocytoma,
acromegaly estrogen therapy
-Neurogenic - Increased ICP, autonomic hyperreflexia
-Misc - Obesity, Hypercalcemia, preeclampsia, ect.
Differential Dx to Hypertension
Consequences of hypertension?
Physiologic - CO increases followed by SVR increases
-Sustained HTN - LVH with impaired ventricular
relaxation known as
diastolic dysfunction, Vascular smooth muscle
hypertrophy, CAD, CHF,
renal issues, increased risk of stroke
-Labile BP’s during surgery
Perioperative tx of HTN?
Treat Pain - Opiods, NSAIDs, Tylenol
Deepen anesthesia
Drugs
Quiz?
How do you treat high blood pressure and low HR?
Diuretic, deepen anesthesia
How do you treat low blood pressure and high HR?
Give fluids, phenylephrine
How do you treat low blood pressure and low HR?
epi, ephedrine, fluids
How do you treat high blood pressure and high HR?
beta blocker, Metroplol, esmolol (has more effect on HR)
How do you treat high blood pressure and maintain HR?
Turn up gases, labetalol (has mores effect on BP)
How do you treat low heart rate and not affect BP?
glycopyrrolate, atropine
