Pulmonary Hypertension in the ED

(By David Warshaw, PGY2 and Naomi Rebollo, PGY3)

7:05am – This is our first patient of the day on your first CCT shift as a senior…

56-year-old female with shortness of breath x a few hours

You quickly scan through her chart and notice a diagnosis of pulmonary hypertension. What do you do in terms of ED management? What are important considerations to keep in mind if this patient crashes?

PULMONARY HYPERTENSION

By the numbers, pulmonary hypertension (pulm HTN) is classically defined as a mean pulmonary arterial pressure above 25 mm Hg. Over time, the gradual increase in vascular resistance in the lungs can lead to RV hypertrophy and eventual RV failure. Worsening RV function will impair the systemic output of the left ventricle, which in turn, decreases perfusion to the right ventricle through the right coronary artery creating a cycle (1).

Pulmonary hypertension actually refers to one of five categories:

1. Arterial, which is usually idiopathic and is very rare
2. Venous, which is usually from left heart disease and is very common
3. Secondary to chronic hypoxemic lung disease, including COPD, OSA, ILD, and being at chronic high altitudes
4. Secondary to embolic disease
5. Other, including myeloproliferative disorders, sarcoidosis, neurofibromatosis, thyroid disorders, and schistosomiasis

Pulmonary hypertension can be acute or chronic. Acute pulm HTN can cause acute RV failure: in this case, think of PE, acute LV failure, and hypoxia as possible underlying causes.

Chronic pulm HTN progresses over weeks to months to years, with patients normally reporting chest pain, shortness of breath, weakness, or fatigue. The classic patient is a middle-aged woman who complains of shortness of breath but has clear lung sounds on exam. Many patients wait up to two years for definitive diagnosis, and a 2013 study from Australia found a mean time to diagnosis of almost four years (2). Thus, this is generally not an ED diagnosis and can be extremely hard to recognize. Keep this diagnosis in your differential for patients with multiple ED visits for dyspnea with negative ED workups. 

The only way to definitively diagnose pulm HTN is with right heart catheterization: Pulmonary capillary wedge pressures (roughly a measure of left atrial pressures) is  < 15 mm Hg in pulmonary arterial hypertension and > 15 mm Hg in pulmonary hypertension from left heart disease.

In the ED, what clinical information suggests pulmonary hypertension?

This is a complicated question, but there are a few key findings that may point you towards the diagnosis.

Most importantly, pulm HTN often occurs in the setting of another disease process. So in a patient with pulm HTN secondary to chronic lung disease, you may see tripoding or clubbing or a hyperinflated chest on the x-ray. In a patient with idiopathic pulm HTN, the picture is a little less clear.

LABS AND IMAGING

In general, progressive RV strain in pulmonary hypertension can show up as mild elevations in troponin or BNP, since the walls of the heart are being stretched and dilated. 

Chest x-ray may reveal cardiomegaly, RV enlargement on lateral views, or provide information on a precipitating cause. 

The ECG may show right heart strain patterns, such as a right axis deviation or right bundle branch block, T wave inversions in leads V1-V4, the S1Q3T3 pattern classically associated with PE, p waves > 2.5 mm in the inferior leads (often called p pulmonale), or even new-onset atrial fibrillation.

However, the most useful technology in the ED is bedside ultrasonography (1, 3, 4).

ECHOCARDIOGRAPHY

Keep your eyes on the right ventricle when you’re concerned about pulm HTN. On bedside echo, you may see right atrial or ventricular hypertrophy, dilation of the right atrium, or the D sign, meaning a bowing of the interventricular septum that suggests right ventricular strain. Here’s an example of the D sign (5):

Other ultrasound images of right heart failure can be found in The POCUS Atlas.

TREATMENT

Again, pulm HTN usually occurs due to an underlying disease process – so you can focus your treatments on that disease. However, there are some medications that can help reduce pulmonary vascular resistance and improve right ventricular function. Of course, you should place these patients on supplemental oxygen if needed, as avoiding hypoxemia is high-priority. Be wary of intubation, as sedating medications and positive pressure ventilation can reduce blood pressure and right ventricular function by decreasing venous return. Keep MAP above 65 mm Hg to ensure blood flow to the right ventricle using norepinephrine if needed. If intubation is absolutely required, use the lowest PEEP possible and keep tidal volumes at lung-protective settings (about 6 mL/Kg). Consider inhaled nitric oxide as an adjunct to vasodilate the pulmonary vasculature. 

To augment RV function, you can start with 250 mL fluid boluses. If there is no improvement, you can use dobutamine, starting at 2 mcg/kg/min, or milrinone, which dilates the pulmonary vasculature, starting at 0.3735 mcg/kg/min. Patients with chronic pulm HTN may be on sildenafil (a phosphodiesterase-5 inhibitor) or bosentan (an endothelin receptor-antagonist), which both act to reduce pulmonary vascular resistance (6). Continue administering these medications in the ED.

In most patients, treating the underlying disease will help to reduce pulmonary vascular resistance. It’s still important to keep idiopathic pulm HTN in mind, and make sure to keep your ultrasound charged and ready to use!

References:

1. Winters ME. “Pulmonary Hypertension.” In: Tintinalli JE. Tintinalli’s Emergency Medicine. 8th ed. New York: McGraw-Hill Medical; 2016: 409-412.
2. Strange G et al. Time from symptoms to definitive diagnosis of idiopathic pulmonary arterial hypertension: The delay study. Pulm Circ. 2013 Jan-Mar; 3(1): 89–94.
3. Greenwood JC, Spangler RM. Management of Crashing Patients with Pulmonary Hypertension. Emerg Med Clin North Am. 2015 Aug;33(3):623-43.
4. Morgenstern J. Resuscitation of pulmonary hypertension and right ventricular failure. First10EM. Online. https://first10em.com/pulmonaryhtn/
5. Almanzar-Ramos H. Pulmonary Hypertension and the D-Sign. LLU Ultrasound. Loma Linda University. Online, 2017. https://lluultrasound.org/home/blog/2017/10/23/pulmonary-hypertension-d-sign/ 
6. Hohsfield R et al. Pulmonary Arterial Hypertension Emergency Complications and Evaluation: Practical Guide for the Advanced Practice Registered Nurses in the Emergency Department. Adv Emerg Nurs J. 2018 Oct-Dec; 40(4): 246–259.

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David Warshaw

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