HYPERTENSIVE EMERGENCIES

AND URGENCIES

Dr Manjuprasad Moderator:Dr

Padmaja Udaykumar

• Hypertension (HTN) or high blood pressure - arterial

hypertension

• Chronic medical condition- BP

• Heart - work harder than normal to circulate blood

through the blood vessels

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JNC- 7

• Normal – SBP<120 and DBP<80

• Prehypertension – SBP 120-139 or DBP 80-89

• Stage I hypertension – SBP 140-159 or DBP 90-99

• Stage II hypertension – SBP >160 or DBP >100– Hypertensive urgency

– Hypertensive emergency3

• Hypertensive emergencies:

Severe elevation in BP complicated by impending or

progressive target/end organ damage

• Hypertensive urgencies:

Severe elevation in BP without any target organ damage

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CNS - encephalopathy, intracranial

hemorrhage, Grade 3-4 retinopathy

Kidneys - acute kidney injury,

microscopic hematuria

Vasculature - aortic dissection, eclampsia

Heart - CHF, MI,

angina

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Conditions constituting evidence of

end organ damage

• Hypertensive encephalopathy

• Intracerebral hemorrhage

• Stroke

• IHD- AMI, acute LVF with papilloedema,

angina

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• Eclampsia

• Life threatening arterial bleed

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ETIOLOGY

• Poor treatment or abrupt discontinuation of the

treatment

• Renal parenchymal disease

• Drugs

• Coarctation of aorta

• Pre eclampsia/ eclampsia

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PATHOPHYSIOLOGY

• Failure of normal autoregulation

• Release of vasoconstrictors from stressed walls

• Endothelium plays an important role in BP

homeostasis

• Increase in pressure starts a cycle

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MANAGEMENT

• BP should never be reduced to normal values

- Risk of ischemia and infarction.

• Gen rule:

- MAP should be lowered no more than 20% in first hour

- If pt remains stable, BP lowered to 160/110 in next 2-6

. hrs

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Treatment goals achieved by

- continuous infusion of a short acting, titratable,

parenteral antihypertensive agent along with constant

BP monitoring

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TREATMENT

Medication options

1. Oral antihypertensives

• Chronic hypertensive

• Hypertensive urgency

2. IV antihypertensives

• Hypertensive emergency

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IV antihypertensive

• Vasodilators

sodium nitroprusside

nitroglycerine

nicardipine

fenoldopam

hydralazine

enalaprilat

• Adrenergic

inhibitors

labetalol

esmolol

phentolamine

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Ideal IV antihypertensive

• Lower BP without compromising blood flow to critical organs

• Vasodilators- preserve organ blood flow in the face

. of decreased perfusion

- also tend to increase cardiac output

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Profile of ideal antiHTN

• Preserves GFR

• Few or no drug reactions

• Rapid onset and offset of action

• Minimal hypotension

• Minimal need of continuous BP monitoring

• No acute tolerance

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• Ease of use and convenient

• Safe and no toxic metabolites

• Minimal sympathetic activation

• Multiple formulations for short and long term use

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Sodium Nitroprusside

MOA:- direct smooth muscle dilator

- Nitric oxide component

-reduces preload and after load

- causes cerebral vasodialation

• Ultra short acting

• Immediate onset - DoA : 10min

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• Dose:

0.1-0.5mcg/kg/min IV infusion

titrate to desired effect

rates>10mcg/kg/min

Adverse effects/Precautions:

Cyanide toxicity

precipitous drop in BP

continuous BP monitoring

reflex tachycardia

Nausea and vomiting

Increased ICP

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Uses

Drug of choice:

• Perioperative HPT

• Cocaine toxicity

• Aortic dissection(combination)

• Neurologic syndromes

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Nitroglycerine

MoA:

• Potent vasodilator

• Decrease preload (CO + BP)

• Decreases coronary vasospasm

• Dose: cont infusion

start 5mcg/min, incr by 5mcg/min

every 3-5min to 20mcg/min

If NO Response

increase by 10mcg/min every 3-5min,up

200mcg/min

• Onset : 2-5min/DoA : 5-10min21

• Adverse effects/precautions:– Constant monitoring is essential

– Tolerance from uninterrupted use (12hr withdrawal)

– Headache, tachycardia, flushing

• Contra ind:– Concurrent use with PDE-5 inhibitors - causes significant

hypotension

– Head trauma/cerebral haemorrhage

– Severe anaemia

• Drug of choice:– Acute HF

– ACS

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Nicardipine

• Ca channel blocker – selective arterial vasodilator

• Onset: 1-5min

DoA: 15-30min

Dose: start 5mg/hr IV infusion, titrate every

15min to max 15mg/hr.

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Advantages:

• Cause cerebral and coronary vasodilatation

• Precautions: can worsen/cause HF and

liver failure

can exacerbate renal insuff.

• Ideal for CNS emergencies

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Fenoldapam

MoA:

• Peripheral dopamine agonist (high vs low doses)

causes selective neuro vasodilatation

• mesenteric vasodilatation

• increases renal blood flow and sodium excretion

Onset – <5min, but more gentle, lasts for 30min

Standard BP monitoring is sufficient, no toxic

metabolites

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Dosing:

• Start at 0.1-0.3mcg/kg/min IV infusion

• May be increased in increments of 0.05-

0.1mcg/kg/min every 15min, until target BP

reached

• Max infusion rate – 1.6mcg/kg/min

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Precautions:

• Pts with glaucoma

• Dose related tachycardia can occur – angina

• Close BP monitoring

• Close K+ monitoring

• Caution with raised ICP

Drug of choice

• Renal insufficiency

• Stroke ( combination with nicardipine)

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HydralazineMoA:

• Decreases systemic resistance by direct vasodilation

of arterioles

Dose:

• 5-20mg IV bolus or 10-40mg IM repeat every 4-6hrs

• boluses takes 20min to work

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Adverse effects/Precautions

• Tachycardia, flushing, headache

• Sodium and water retention

• Increased ICP

• Adjust dose in severe renal dysfunction

• Response may be delayed and unpredictable

• Still drug of choice in pregnancy(Eclampsia)

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Enalaprilat

• The active component of Enalapril (hydrolyzed in liver

and kidney)

MoA:

• ACE inhibitor

Dose:

• 0.625-2.5mg every 6hr IV

• Onset – within 30 min + long half life

Adverse effects/Precautions

• Contra-indicated – volume depletion, renal vascular

disease

• Prolonged t½ 30

Labetalol

MoA:

• selective alpha blocker – reduce vascular smooth

m. resistance

• non-selective Beta blocker – ↓ cardiac inotropy and

myocard O2 consumption → prevent reflex

tachycardia

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Dose:

Bolus: effect in 5-10min,max effect at 20min. (DoA:

2-6hrs).

• Cont. infusion: 0.5 – 2mg/min – titrate to

response, max 300mg

• Difficult to titrate due to very wide dose range

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Advantages:

• smooth onset

• Transition to oral Rx easy (dose equivalent)

• Improve cerebral blood flow – stroke pt

• No need for ICU/Arterial line

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• Adverse effects/precautions

– Relative CI – Heart failure, heart block, Asthma (bronchoconstriction)

– Vomiting, scalp tingling

– Impaired hepatic function

• Contraindicated in HPT secondary to Cocaine use

(B-blocker effect outway the alpha effect, thus unapposed alpha constriction)

• Drug of choice:

– Aortic dissection

– Hypertensive emergencies

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Esmolol

MoA:

• highly selective beta blocker

Dose:

bolus: 250-500mcg/kg IV over 1-3min

• infusion: 50-100mcg/kg/min

• may repeat bolus after 5min or increase

infusion rate to 300mcg/kg/min

Onset 1-2min / short acting

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Adverse effect/Precautions

• Hypotension common

• nausea

• Asthma

• 1st degree AV block

• heart failure

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Contraindications

• Sinus bradycardia

• Heart block

• Cardiogenic shock

• Bronchial asthma

• Uncompensated CF

Drug of choice:

• Aortic dissection ( with nitrate)

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Phentolamine

MoA:

• alpha adrenergic receptor blocker

Dose:

• load 5-20mg IV every 5min or

• infusion 0.2-0.5mg/min

• Onset 1-2min

Adverse effect/precautions

• tachycardia

• flushing/headache

• MI

• cerebrovascular spasm38

• Contra-indications– renal impairment

– Concurrent use with PDE-5 inhibitors

– coronary or cerebral arteriosclerosis

• Drug of choice– Cocaine associated HPT crisis

– Pheochromocytoma HPT crisis

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Neurological emergencies

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Hypertensive encephalopathy

– reduce MAP by 25% or diastole to 100mmHg

over 8 hrs

– If neurology worsens, suspend Rx

– Drug of choice:

• Sodium nitroprusside

• Labetalol

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Acute Ischemic stroke

• often loss of cerebral autoregulation

• ischemic region more prone to hypoperfusion

• thus BP reduction not recommended

• unless SBP>220 or DBP>120

• UNLESS planning fibrinolysis – SBP<185

and DBP< 110

Drug of choice:

• Labetalol

• Nicardipine

• Sodium Nitroprusside

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Acute ICH/SAH

• Treatment based on clinical/radiographic

evidence of raised ICP

• Raised ICP – MAP<130 (1st 24hrs)

• No raised ICP – MAP<110

Drug of choice:

• Sodium Nitroprusside

• Labetalol

• Nicardipine

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Cardiovascular emergencies

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ACS• Treat if SBP>160 and or DBP>100

• Reduce MAP by 20 -30% of baseline

• Nitrates should be given till symptoms

subside or until DBP<100

Drug of choice:

• Nitroglycerine

• Labetalol

• Nicardipine

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Acute HF (pulmonary edema)

• Treat with vasodilator (additional to diuretics)

• Sodium Nitroprusside in conjunction with

• Morphine, oxygen and loop diuretic

• Enalaprilat also an option

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Aortic dissection• anti-hypertensive Rx is aimed at reducing the

shear stress on aortic wall (BP and Pulse)

• immediate lowering of BP – lifesaving

• maintain SBP<110, unless signs of end

organ hypoperfusion

preferred Rx is combination of Morphine,

• B-blocker and vasodilator

• Nitroprusside + Labetalol

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Other disorders

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Cocaine toxicity/pheochromocytoma

– Hpt and tachycardia rarely require specific Rx

– Alpha adrenergic blockers – preferred

– B – blockers can be added, but only after

alpha blockade.

Drug of choice

• Phentolamine

• Labetalol

• Diazepam

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Pre-eclampsia/Eclampsia

– Goal SBP<160 and DBP<110 in pre-and-

intrapartum periods.

– Platelets < 100 000, BP should be maintained <

150/100

– IV Magnesium to prevent seizures

Drug of choice:

• Methyldopa

• Hydralazine

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Perioperative hypertension

– Target BP to within 20% of baseline, except if

potential for life threatening arterial bleeding

– Typically related to catecholamine surge post-

op.

Drug of choice:

• B-blocker

• Labetalol

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References

• Goodman and Gilman – 12th edition

• Rang and Dales pharmacology 7th edition

• Textbook of medical pharmacology – Padmaja

udaykumar

• Hypertensive emergencies- Louis Muller

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• Cheese reaction, cold remedy

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