Anesthesia Lab II: Lecture 6 - Hypertension Flashcards
(32 cards)
What is hypertension?
Defined by blood pressure >140/90
What is the most common cause of hypertension?
Essential hypertension
List some common medications used to treat hypertension.
- Beta blockers
- Calcium channel blockers
- ACE inhibitors
What is the relationship between age and hypertension incidence?
Increasing incidence with increasing patient age
What are some comorbidities associated with hypertension?
- CAD
- Diabetes
- Obesity
- Hyperlipidemia
Why is hypertension a concern?
Prolonged untreated hypertension can lead to serious conditions such as heart failure, renal insufficiency, stroke, vascular dementia, and aneurysm rupture
What are some intraoperative risks associated with hypertension?
- Worsening surgical bleeding
- Stroke
- Myocardial infarction (MI)
- Pulmonary edema
- Aneurysm rupture
When do we treat hypertension during surgery?
Varies by surgery and patient
Some surgeries require relative hypotension (ENT, total joint surgery, AAA)
Some surgeries require intentional hypertension (cerebral embolectomy, beach chair positioning)
Many surgeries require very tight BP control, such as ruptured aneuryms, cerebral hemorrhage, ruptured globe, arthroscopic surgery
General rule: keep the patient within 20 % of baseline BP due to cerebral autoregulation
Name a type of surgery that may require relative hypotension.
ENT surgery
What is the general rule for blood pressure control during surgery?
Keep the patient within 20% of baseline BP due to cerebral autoregulation
What is the primary mechanism of drug delivery in the OR once intubated?
IV (intravenous) administration
How do we treat hypertension in the OR?
Variety of drug class options available
Once intubated, IV is primary mechanism of delivery
Decision on drug class depends on comorbidities, HR, allergies
Example: use caution in selected patients with history of heart block, asthma/emphysema, those already on nodal blocking agents
Use caution when combining agents due to depressive effects
Primary classes of focus: vasodilators, beta-adrenergic antagonists, calcium-channel blockers
What are the primary classes of drugs used to treat hypertension in the OR?
- Vasodilators
- Beta-adrenergic antagonists
- Calcium-channel blockers
What is the mechanism of action for beta blockers?
Bind to beta-adrenoceptors and block norepinephrine and epinephrine binding
This inhibits normal sympathetic effects that act through these receptors. Therefore, beta-blockers are sympatholytic drugs
Both selective and non-selective options
Used both as an anti-hypertensive and antiarrhythmic
Also commonly used in the management of heart failure
Contraindicated in bradycardia and AV nodal blocks
What are the three main beta blockers anesthesia uses?
Metoprolol
Selective Beta-1
IV dose 1-2mg
Short duration of action
Esmolol
Selective Beta-1
IV dose 10-20mg
Ultra-short duration of action
Labetalol
Both alpha and beta agonist
IV dose 5mg
Longer duration
What is a contraindication for beta blockers?
Bradycardia and AV nodal blocks
What is the IV dose of Metoprolol?
1-2 mg
What distinguishes Esmolol from other beta blockers?
Ultra-short duration of action
What is the mechanism of action for calcium channel antagonists (CCBs)?
Block the inward movement of calcium by binding to L-type voltage-gated calcium channels in the heart, vascular smooth muscle, and pancreas
Two Classes: non-dihydropyridines and dihydropyridines
Dihydropyridines: amlodipine, nicardipine
Non-dihydropyridines: verapamil, diltiazem
Non-DHP: inhibitory effects on the SA node& AV node slows conduction & contractility
This allows for the treatment of hypertension, reduces oxygen demand, and helps to control the rate in tachydysrhythmias
DHP: peripheral vasodilators
useful for hypertension, post-intracranial hemorrhage associated vasospasm, and migraines
Indications, Side Effects and Contrainidications for CCBs
Indications: hypertension, coronary spasm, angina pectoris, supraventricular dysrhythmias, hypertrophic cardiomyopathy, and pulmonary hypertension
Side Effects:
Dihydropyridines may lead to lightheadedness, flushing, headaches, and peripheral edema.
peripheral edema is likely related to the redistribution of fluid from the intravascular space to the interstitium
Non-DHP can lead to bradycardia
Contraindications:
Non-DHP are contraindicated in heart failure with reduced EF, second or third-degree AV blockade, & sick sinus syndrome due to the potential for bradycardia and worsening cardiac output
Allergy to CCBs
Severe hypotension, acute MI, pulm edema
List examples of dihydropyridines.
- Amlodipine
- Nicardipine
What are the effects of non-dihydropyridines?
Inhibitory effects on the SA node and AV node, slowing conduction and contractility
What are the indications for using calcium channel antagonists?
- Hypertension
- Coronary spasm
- Angina pectoris
- Supraventricular dysrhythmias
- Hypertrophic cardiomyopathy
- Pulmonary hypertension
What are common side effects of dihydropyridines?
- Lightheadedness
- Flushing
- Headaches
- Peripheral edema
