Hypertensive emergency

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High blood pressure without symptoms is NOT hypertensive emergency (see asymptomatic hypertension)

Background

  • Definition: end-organ damage due to hypertension
    • Blood pressure is generally >180/120 (usually > 220/130), but presence of end-organ damage defines disease (not absolute blood pressure number)

Etiology

  • Idiopathic
  • Sympathomimetic drug use
  • Preeclampsia
  • Acute glomerulonephritis

Prehospital

  • Prehospital BP measurements should be considered reliable[1]
  • Acute lowering of BP is not typically recommended
  • Focus on ABCs (assess need for Intubation or respiratory support)
  • Provide care of treatable etiologies

Clinical Features

End-Organ Dysfunction[2]

Differential Diagnosis

Hypertension

Evaluation

Consider any of the following based on the patient's clinical presentation[3]

  • CBC - assess for hemolytic anemia
  • Chem 8 - assess renal failure and possible secondary causes
  • Cardiac enzymes
  • Urinalysis - Assess renal failure, glomerulonephritis, preeclampsia
  • Chest Xray - evaluate for pulmonary edema or dissection
  • ECG - LVH, ischemia

Treatment

  • Goal: Lower diastolic pressure to 105 mmHg within 2-6 hours
    • Maximum initial fall in BP should not exceed 25% of presenting value in 1st hour
  • Be careful of lowering BP in patients with CVA

By Drug

Drug Dose Mechanism Pros Cons Notes
Nitroprusside

0.3-0.5 mcg/kg/min IV initial infusion

Incr by 0.5mcg/kg/min up to 2mcg/kg/min


Arterial > veno-dilator

1. Very effective

2. Immediate onset/offset

1. Cyanide Toxicity

2. Coronary steal?

3. Incr HR

1. Avoid in liver/renal failure

2. Avoid with increased ICP

3. Avoid in pregnancy

Nitroglycerin Start 5-100 mcg/min Veno>arteriodilation

1. Rapid on/offset

2. Increases coronary flow

Causes Tachycardia

Drug of choice in patients with cardiac ischemia,

LV dysfunction, or pulmonary edema

Labetalol

20-80mg IV bolus q10min OR

0.5-2mg/min IV infusion or

200mg to 400mg PO BID

Beta>α-blocker

1. No change in HR, cerebral flow 2. Rapid onset

Avoid in COPD, CHF and heart block

1. Consider in ACS 2. Consider in ischemic CVA

Esmolol

Load 250-500 mg/kg/ over 2min

Infuse 50mcg/kg/min over 4min

- if ineffective repeat load, increase infusion rate by  50mcg/kg/min up to 200mcg/kg/min

Beta selective Rapid on/offset

Avoid in COPD, CHF

bradycardia

Consider in ACS

Nicardipine

Start 5mg/h

If ineffective after 15min increased in 2.5mg/hr interval up to 15mg/hr

Decreases PVR

Good for intracranial pathology Slower onset/offset Avoid in CHF, ACS
Phentolamine

5-10mg IV bolus q5-15min OR

0.2-5mg/min IV infusion

α-blocker Used for catecholamine-induced hypertension
Enalaprilat Bolus 1.25mg over 5min q6hr, titrate at 30min intervals to max of 5mg q6hr Decreases HR, SV, systemic arterial pressure Does not impair cerebral flow Variable response

1. Used in patients at risk for cerebral hypotension, CHF

2. Avoid in pregnancy

Clonidine

0.1 - 0.3 mg PO q12 scheduled; For hypertensive emergency, 0.2 mg x1, then 0.1 mg q1 hr PRN, max 0.6 mg total

α-2 agonist, BP effects within 30-60 min after PO dose Reduced CNS sympathetic flow, decreasing SVR, HR, BP; no renal blood flow changes; tolerance/tachyphylaxis develop quickly


Hydralazine

10 - 20 mg slow IV/IM bolus q4-6 hr PRN, max 40 mg/dose

Peripheral vasodilator, with fall in BP beginning within 30 min, lasting 2-4 hrs Decrease in DBP > SBP; has increased HR, stroke volume and cardiac outpt; preferential vasodilation > venodilation


By Disease

Aortic Dissection

  • Rapidly reduce sys BP to 100-120; HR 60-80 within 20min
  • Avoid volume depletion
  • Prevent reflex tachycardia
    • Labetolol alone
    • Nitroprusside or nicardipine AFTER metoprolol or esmolol

Pulmonary Edema

  • Reduce BP by 20-30%
  • Promote diuresis AFTER vasodilation

ACS

  • No more than 20-30% reduction for SBP >160
  • Consider NTG, beta-blocker

Cocaine/Amphetamine Toxicitiy

  • Benzos
  • Mixed α + B blockade
    • Phentolamine OR nitroprusside AND β-blocker

Renal Failure

  • Reduce BP by no more than 20%
  • Avoid nitroprusside (renal metabolism)
  • Labetalol or nicardipine

Eclampsia/Pre-eclampsia

  • Goal BP <160/110
  • Labetalol or nicardipine
  • Magnesium

Encephalopathy

  • Decrease MAP by 15-20%
    • Avoid overly aggressive lowering
  • Nicardipine or labetalol

CVA

Pheochromocytoma

  • Phentolamine OR (nitroprusside AND β-blocker)

See Also

Video

References

  1. Cienki JJ, DeLuca LA. Agreement between emergency medical services and expert blood pressure measurements. J. Emerg Med. 2012;43(1):64-68.
  2. Levy PD. Hypertensive Emergencies — On the Cutting Edge. EMCREG - International. 2011. 19-26.
  3. 2013 Practice guidelines for the management of arterial hypertension of the European Society of Hypertension (ESH) and the European Society of Cardiology (ESC): ESH/ESC Task Force for the Management of Arterial Hypertension. J Hypertens. 2013;31(10):1925-1938.
  4. Acute Stroke Practice Guidelines for Inpatient Management of Ischemic Stroke and Transient Ischemic Attack (TIA) https://www.heart.org/idc/groups/heart-public/@wcm/@private/@hcm/documents/downloadable/ucm_309996.pdf