Definition of Hypertensive Crisis.
Acute elevations of blood pressure
Sudden increase in SBP or DBP
Causes have end organ failure
Define Hypertensive Urgencies.
Severely elevated BP without acute end-organ damage
BP control can be achieved within a few hours to prevent organ damage
No specific BP value
Define Hypertenisve Emergencies.
Presence of target organ damage rather than BP value
Start BP control within 1 hour
Attempt to avoid further end organ damage
What is the JNC 7 definition of hypertensive emergency.
BP >180/120 complicated by evidence of impending or progressive end organ damage
What is the JNC 7 definition of hypertensive urgency.
Severe elevation in BP without progressive end organ damage
What are some examples of Hypertensive Emergencies.
Hypertensive encephalopathy
Acute Aortic Dissection
Acute Pulmonary Edema with Resp Failure
Acute MI/Angina
Eclampsia
Acute renal failure
Microangiopathic hemolytic anemia
Explain Malignant HTN.
A misnomer
Commonly used term since 1923
What is the STAT Registry?
Studying the Treatment of Acute HyperTension
Goal is to have better understanding the clinical condition of acute HTN managed in a critical care setting and treated with IV antihypertensive drugs
What is the equation for CPP?
CPP=MAP-ICP
What is the normal ICP?
10-15
What are some symptoms of hypertensive emergencies?
Varies from patient to patient
Headache
Fatigue
Chest Pain
Dyspnea
Cough
Paresthesias
Altered Mental Status
What is important in the H&P process of emergent hypertension?
Targeted medical history and physical examination included prior use of antihypertensive, use of MAOs, recreational drugs, check BP in all limbs, use correct cuff size
Want to get CBC, BMP, UA, CXR, EKG, CT head/chest
What is important to remember in management of hypertensive emergency.
Do not drop the BP too fast!
What are some of the causes of hypertensive emergencies?
Uncontrolled hypertension (non-compliance)
Drug induced hypertension (cocaine, amphetamine, drug withdrawal, drug-drug interactions)
Endocrine disorders
What are some causes of HTN Urgencies?
Recent discontinuation of anti-HTN drugs
Need for emergent surgery
Severe body burns
S/P Kidney Transplant
Subacute renal failure
What is the treatment for HTN in inpatients?
Treat the underlying cause
Provide adequate anesthesia/analgesia
Administer antihypertensive medications
Consider the ICU
What are important keys to remember in pharmacologic management of hypertension?
Both SBP and DBP must be reduced
No more than 15% reduction during the first hour
Gradual reductions thereafter (25% of initial BP is the goal)
Any reduction in BP can cause ischemia - must have careful and close monitoring, consider arterial line and ICU
How do you choose your pharmacologic agent in hypertensive management?
Must determine if emergency or urgency
IV followed by PO
Choose the drug with least side effects
Cost is important to consider as well
Nitroprusside
Combined arterial and venous vasodilator
MOA: cGMP formation with smooth muscle relaxation
Cerebral blood flow decreases (dose-dependent)
Advantages of Nitroprusside
Immediate onset
Short duration of action
Potent
Limitations of Nitroprusside
Light sensitive
Arterial catheter usually recommended
ICU-level care usually required
Adverse effects of nitroprusside
Excessive hypotenisve
Tachyphylaxis (hyper dynamic response)
Redistribution of flow (Intrapulmonary shunt, coronary steal, reduced blood flow)
Platelet dysfunction
Toxicity - cyanide, thiocyanate
What are the signs of cyanide toxicity.
Hypotension
Increased mixed venous saturation
Metabolic acidosis
Altered mental status
Seizures
Death may be very rapid.
What is the treatment for cyanide toxicity?
Discontinue infusion immediately
ABCs
Treat hypotension and seizure in usual fashion
Administer cyanide antidote kit
Call Poison control for questions
Nitroglycerin
Coronary vasodilator
Direct venodialtor
Requires special tubing for administration
What are the SE of nitroglycerin?
Headaches and tachycardia
Variable efficacy and tachyphylaxis
Methemoglobinemia
Labetolol
Combined alpha and beta blocker
Onset of action within 5 minutes
Decreases SVR and CO (do not use in patients with low EF)
What is the dose range for labetolol?
IV bolus dose 0.25mg/kg followed by 0.5mg/kg q15 minutes
Advantages of Esmolol.
Easy to titrate
Short 1/2 life
beta-1 selective antagonist
Quick onset of action
Metabolized by red blood cell esterase's
Myocardial depression
When should caution be used with esmolol administration?
Reactive airway disease
Phenolamine.
Alpha-adrenergic blocking agent
Excellent for cathecolamine-induced HTN crisis
What is the dosing of phenolamine?
IV bolus 5-10mg
What are the SE of phenolamine?
May cause tachydysrhythmias or angina
Clonidine
Alpha agonist
Central acting agent
What is the dose of clonidine?
0.1mg PO (q20 min to max of 0.8)
What are the advantages of clonidine?
More gradual decrease in BP
Sedation is a significant side effect
Excellent for patients that do not require immediate BP control
IM/IV form available outside US for BP control and for anesthesia use in US
Nefedipine
Causes vasodilation of arterioles
Action begins 10-15 minutes
Unknown peak (30 min??)
Suddent reductions in BP (acute CVA, MI)
Reflex tachycardia (AMIs)
What is the FDA's statement regarding the use of nifedipine?
The routine use of this drug in hypertensive emergencies should abandoned.
Why should nifedipine not be used in hypertensive crisis?
May cause severe hypotension, acute MI, stroke, and death due to:
Uncontrollable decrease in BP
Peripheral vasodilation producing steal phenomena
Reflex effects including catecholamine release
SL absorption negligible.
Nicardipine.
Dihydropyridine calcium channel blocker
IV Calcium channel blocker indicated for the treatment of hypertension
Inhibits transmembrane influx of calcium ions into cardiac and smooth muscles without changing serum calcium concentrations
Produces significant
What is the dose range for nicardipine?
5mg/hr increase by 2.5mg/her q5-15 minutes
Max dose was 15mg/hr
Clevidipine
Ultra short acting CCB
Initiated at 2mg/hr
Titrated by doubling increments Q3 minutes, not to exceed 32mg/hr
Treatment duration not to exceed 96 hours.
Lipid infusion
Captopril
ACEI
Effects seen in 5 minutes
SL dosing
Enalapril
IV ACEI
Suddent reduction of BP
No significant increase in HR
Fenoldopam
Dopamine-1 agonist
Systemic vasodilation
Does not cross blood brain barrier
Coronary vasodilation without steal effect
Mesenteric vasodilation
What are some warnings associated with Fenoldopam?
Contains sodium metabisulfate, a sulfite that may cause allergic type reactions including anaphylactic symptoms and life threatening or less severe asthmatic episodes.
What is the dosage for fenoldopam?
0.1mcg/kg/min