Nebulised GTN in the ED

Case Study

A 58-year-old female, being actively treated for lung cancer, is brought to the emergency department with severe shortness of breath.

Last week she had been admitted to hospital for drainage of a malignant pleural effusion. During this admission she developed right vocal cord paralysis and prior to discharge her CT brain demonstrated suspected brain metastasis.

Vitals on arrival:

SpO2 92% (on 15L via NRBM); RR 28; HR 128; BP 86/42; Temp 36.4.

Initial management

A bolus of 500ml N/saline was administered, a radial arterial line inserted, and peripheral noradrenaline commenced.


Pulmonary embolus was suspected and CTPA revealed left lobar segmental and subsegmental emboli with associated right heart strain.  

Selected blood results include

  • troponin 550, CRP 119, potassium 3.3
  • pH 7.28 , PaO2 26, PCO2 38

Further management

On return from CT, the patient was transitioned to high flow nasal oxygenation (HFNO) and required FiO2 100% at 30L/min to maintain an SpO2 of 95%.

She became progressively haemodynamically compromised maintaining a MAP of 55mmHg on high-dose peripheral noradrenaline. With the addition of a vasopressin infusion and calcium gluconate the MAP was maintained above 65mmHg. Thrombolysis was discussed, but not administered within the context of new brain lesions and co-morbidities.

The patients oxygen requirements continued to rise despite HFNO, and it was decided to trial nebulised Glyceryl trinitrate (GTN). The patient received 3 x 5mg GTN nebs over 75mins and her oxygen requirements decreased to FiO2 70%, 8L/min with a respiratory rate of 22 and SpO2 97%. There was no change in haemodynamics or increased vasopressors during the GTN nebs.

She remained stable on this from an oxygen requirement and was transferred to ICU with reducing oxygen requirements from the HFNO.

Why consider nebulised GTN?

Patients presenting with massive pulmonary embolism or decompensated pulmonary hypertension have similar pathophysiology that results in increased pulmonary artery pressures that can spiral into right ventricular failure and haemodynamic collapse.

Nebulised GTN is cheap, readily available and can be made up quickly at the bedside in patients who are crashing with worsening hypoxaemia and would benefit from inhaled pulmonary vasodilators.

How does nebulised GTN work?

Nitroglycerin is metabolised into nitrous oxide (NO) which causes an increase in cyclic guanosine monophosphate in the vascular smooth muscles that results in vasodilation.

Nebulised nitroglycerin largely remains in pulmonary vasculature without systemic side effects on the cardiovascular system, i.e. hypotension.  Nitric oxide in the pulmonary vascular bed adjacent to ventilated alveoli, enhances in pulmonary venodilation and reduces pulmonary arterial pressure and vascular resistance.

What are the clinical indications to try nebulised GTN?

Nebulised GTN can assist in pulmonary artery vasodilation and improvement in RV afterload in conditions such as

How do prepare and administer?
  • Presentation: The most common presentation for GTN is 50mg in 10mL, in a vial.
  • Dose: 5mg (1mL) of GTN per nebuliser.
  • Duration of action is 20-30mins
  • Repeat as required, titrate to effect.

In our patient using the high flow nasal prongs it was easy to administer the nebuliser over the top of this, however if this isn’t available consider using standard nasal prongs at 15L and placing neb over the top – depending on what oxygen requirements are required.

The other option is to run the nebulised GTN through an inline circuit with HFNO, with a T-piece adaptor:

What are the side effects or contraindications of nebulised GTN?

Caution should be used in patients with left ventricular failure, as the nebulised GTN can result in decreased pulmonary vascular resistance which in turn causing increase in left ventricular preload that could worsen cardiogenic pulmonary oedema.

Which other agents could be considered?

Other agents to consider for use in the emergency department for pulmonary vasodilation include:

Take home message on nebulised GTN

It should be noted that although sound evidence for this treatment is lacking by way of an RCT, there are numerous anecdotal case reports and smaller studies showing nebulised GTN is an effective treatment in managing the patient with massive PE, severe pulmonary hypertension or refractory hypoxaemia that’s at risk of right ventricle failure spiral and haemodynamic collapse.


FOAM resources:

CCC 700 6

Critical Care


Emergency nurse with ultra-keen interest in the realms of toxicology, sepsis, eLearning and the management of critical care in the Emergency Department | LinkedIn |

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