September 29, 2020

Under Pressure!: Acute Blood Pressure Management in Emergency Medicine

By ejschwartz

Bergthor Jonsson, Cand. Med.

Dr. Jonsson is a second year emergency medicine resident at Mayo Clinic in Rochester, MN

Acute blood pressure management in the emergency department is in my mind one of the most confusing and controversial topics in emergency medicine. Different blood pressure targets have been proposed for a variety of emergency medical and traumatic conditions. Guidelines are made to benefit the majority of patients with each condition but it is always necessary to consider individual factors such as age, preexisting uncontrolled hypertension and other comorbidities.

In some conditions like aortic dissection aggressive management of blood pressure and heart rate can be lifesaving while in other conditions such as ischemic stroke aggressively lowering the blood pressure is likely to cause worse outcomes. Another example of the controversy of blood pressure management is when it comes to management of spontaneous vs traumatic intracranial hemorrhage. In spontaneous intracerebral hemorrhage guidelines recommend prompt treatment of hypertension while in traumatic brain injury guidelines emphasize aggressive treatment of hypotension but do not provide any recommendations on treating hypertension.

The following is my approach to blood pressure management in the ED based on available guidelines. The information provided in this blog post is only intended for educational purposes. To make decisions in clinical practice please read and reference official published guidelines.

Where guidelines do not specify the recommended agent to use I chose to list nicardipine or labetalol as the agents of choice because of widespread availability. Clevedipine might have some added benefit over nicardipine including quicker onset and shorter half-life but most emergency physicians have less clinical experience with this newer medication.

Here is dosing information for two medications commonly used to acutely lower blood pressure in the ED:

Nicardipine infusion:

- Starting dose: 5 mg/h

- Titrate by 2.5 mg/h every 10 min

- Maximum infusion rate: 15 mg/h

Labetalol IV bolus dosing:

- Starting dose: 10-20 mg IV

- Repeat dosing: Same dose or double the dose if little response after 10 min

- Max single dose: 80 mg

- Maximum total dose: If goal is not reached after 300 mg consider other agents

Conditions That Can Present With Hypotension

Sepsis (1)

🎯 Target: MAP >65 mmHg

Agent:

- 1st line: Isotonic crystalloids (30 ml/kg often recommended)

- 2nd line: Norepinephrine (0.05 mcg/kg/h is a reasonable starting dose)

- 3rd line: Add Vasopressin

- 4th line: Add hydrocortisone (use earlier if adrenal insufficiency likely)

Major Trauma (without TBI or spinal cord injury) (2)

🎯 Target (conventional): Resuscitate to SBP > 90 mmHg

🎯 Target (“permissive hypotension” or ”hypotensive resuscitation”): Resuscitate to SBP > 70-80 mmHg or MAP > 50 mmHg

Agent: Blood products (whole blood or pRBCs, plasma and platelets in 1:1:1 ratio)

Traumatic Brain Injury (TBI) (with or without other trauma) (3)

🎯 Target: SBP >110 mmHg at age 50-59 year old >100 mmHg in all other.

💉 Agent:

- IV fluids

- If hemorrhagic shock (e.g. polytrauma): Blood products

- If neurogenic shock: Norepinephrine

Clinical pearls: If using hyperosmolar therapy for increase ICP avoid mannitol if patient has low blood pressure (diuretic effect can lower BP). Consider using hypertonic saline instead.

Hypotension should be treated aggressively but guidelines do not give any recommendations on treating hypertension in TBI.(4) Providing analgesia (and sedation if intubated) is important in the hypertensive TBI patient.

Ruptured Abdominal Aortic Aneurysm (AAA) (5)

🎯 Target: Resuscitate to SBP 70-90 mmHg (and maintained mental status)

💉 Agent: Blood products (whole blood or pRBCs, plasma and platelets in 1:1:1 ratio)

Conditions Where You Might Need to Lower the Blood Pressure in the ED

Aortic Dissection (6)

🎯 Target: HR <60 and SBP <120 mmHg

💉 Agent

- 1st line: Esmolol (to decrease intimal shear forces through reduction in heart rate and stroke volume)

- Bolus 500 mcg/kg, start drip at 50 mcg/kg/min, increase by 25-50 mcg/kg/min every 10 min, rebolus when increasing the dose. Max dose 300 mcg/kg/min.

- 2nd line (If HR <60 on esmolol but SBP remains >120 mmHg): Add nicardipine, clevidipine, or sodium nitroprusside to decrease BP.

Clinical pearls: Treating pain with analgesics can also lower the HR and BP. Most hypertensive emergencies require reduction in the mean arterial pressure by about 20% to 25% over the first 1 to 2 hours, but in acute aortic dissection, both blood pressure and heart rate must be reduced as quickly as possible.

Spontaneous Intracerebral Hemorrhage (ICH) (7)

🎯 Target: SBP <140 mmHg (consider higher target SBP <160-180 if present with SBP >220)

💉 Agent: Nicardipine or labetalol

Aneurysmal Subarachnoid Hemorrhage (SAH) (8)

🎯 Target: SBP <160 mmHg (some recommend SBP <140 mmHg)

💉 Agent: Nicardipine or labetalol

Ischemic Stroke (9, 10)

🎯 Target:

- Before tPA: <185/110 mmHg

- After tPA: <180/105 mmHg

- No tPA: < 220/120 mmHg

💉 Agent: Nicardipine or labetalol

Preeclampsia (11, 12)

🎯 Target: Treat if BP ≥160/110 mmHg. Reduce MAP no more than 25% in the first two hours.

💉 Agent:

- Immediate release nifedipine 10 mg oral. Repeat in 20 min and give 20 mg if still >160/110 mmHg.

- Hydralazine 5 mg IV Repeat in 20 min and give 10 mg IV if still >160/110 mmHg

- Labetalol 20 mg IV Repeat in 10 min and give 40 mg IV if still >160/110 mmHg

Clinical pearl: Also give magnesium for seizure prophylaxis

Hypertensive Emergency (rapid and progressive end-organ damage secondary to severely elevated BP (>180/120))

🎯 Target: Lower SBP no more than 25% in the first hour (13) or lower MAP 10% in the first hour and further 10-15% in the next 2-4 hours. (14)

💉 Agent: Can often use nicardipine or labetalol

Clinical pearl: BP usually >180/120 mmHg Need to have evidence of acute end-organ dysfunction (i.e. hypertensive encephalopathy, intracerebral hemorrhage, acute MI, pulmonary edema, unstable angina, dissecting aortic aneurysm, or eclampsia).

Other considerations: In sympathomimetic toxicity use benzodiazepines and phentolamine but avoid beta blockers (including labetalol) since there is (at least theoretical) risk of unopposed alpha stimulation. For the same reason avoid beta blockers (before adequate alfa blockade) in pheochromocytoma.

Sympathetic Crashing Acute Pulmonary Edema (SCAPE) can be treated with high dose nitroglycerin infusion and non-invasive ventilation.

I want to thank Dr. Fernanda Bellolio and Dr. Emily Woods for reviewing the blog post.

References:

1. Rhodes A, Evans LE, Alhazzani W, Levy MM, Antonelli M, Ferrer R, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016. Intensive Care Medicine. 2017;43(3):304-77.

2. Carrick MM, Leonard J, Slone DS, Mains CW, Bar-Or D. Hypotensive Resuscitation among Trauma Patients. Biomed Res Int. 2016;2016:8901938.

3. Carney N, Totten AM, O'Reilly C, Ullman JS, Hawryluk GWJ, Bell MJ, et al. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. Neurosurgery. 2016;80(1):6-15.

4. Krishnamoorthy V, Chaikittisilpa N, Kiatchai T, Vavilala M. Hypertension After Severe Traumatic Brain Injury: Friend or Foe? J Neurosurg Anesthesiol. 2017;29(4):382-7.

5. Chaikof EL, Dalman RL, Eskandari MK, Jackson BM, Lee WA, Mansour MA, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. 2018;67(1):2-77.e2.

6. Hiratzka LF, Bakris GL, Beckman JA, Bersin RM, Carr VF, Casey DE, Jr., et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the diagnosis and management of patients with thoracic aortic disease. A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology,American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons,and Society for Vascular Medicine. J Am Coll Cardiol. 2010;55(14):e27-e129.

7. Hemphill JC, 3rd, Greenberg SM, Anderson CS, Becker K, Bendok BR, Cushman M, et al. Guidelines for the Management of Spontaneous Intracerebral Hemorrhage: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2015;46(7):2032-60.

8. Connolly ES, Jr., Rabinstein AA, Carhuapoma JR, Derdeyn CP, Dion J, Higashida RT, et al. Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association. Stroke. 2012;43(6):1711-37.

9. McManus M, Liebeskind DS. Blood Pressure in Acute Ischemic Stroke. J Clin Neurol. 2016;12(2):137-46.

10. Powers WJ, Rabinstein AA, Ackerson T, Adeoye OM, Bambakidis NC, Becker K, et al. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2018;49(3):e46-e110.

11. ACOG Committee Opinion No. 767: Emergent Therapy for Acute-Onset, Severe Hypertension During Pregnancy and the Postpartum Period. Obstet Gynecol. 2019;133(2):e174-e80.

12. Leeman L, Dresang LT, Fontaine P. Hypertensive Disorders of Pregnancy. Am Fam Physician. 2016;93(2):121-7.

13. Whelton PK, Carey RM, Aronow WS, Casey DE, Jr., Collins KJ, Dennison Himmelfarb C, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018;71(6):1269-324.

14. Elliott WJ. Clinical features in the management of selected hypertensive emergencies. Prog Cardiovasc Dis. 2006;48(5):316-25.

Tags: emergency medicine, hypertension, hypotension, Uncategorized

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