Deadly Mnemonics: Stop Using MONA to Manage Acute Coronary Syndrome

• The mnemonic device “MONA,” which stands for morphine, oxygen, nitroglycerin, and aspirin, is outdated and can be harmful to patients with acute coronary syndrome. 
• Instead of giving every patient with chest pain morphine, oxygen, and nitroglycerin, nurses should prioritize early recognition, such as an ECG and lab diagnostics. 
• Nurses should question any provider or nurse teaching this mnemonic since it is not supported by evidence to improve patient outcomes. 

A 65-year-old patient presents to the emergency department with severe, crushing chest pain, and you are the assigned nurse on duty. You correctly suspect the patient is having a myocardial infarction (MI) and need to predict the appropriate nursing interventions and treatment. Sound familiar?

You might have encountered the MONA mnemonic device in nursing school when learning about Acute Coronary Syndrome (ACS). MONA stands for “morphine, oxygen, nitroglycerin, and aspirin.” The logic behind these medications or interventions is to vasodilate the blood vessels, relieve pain, and increase perfusion to the heart muscle. While that sounds like a great plan, several of these interventions cause more harm and worsened outcomes than alternative medications or therapies. MONA is considered an outdated practice and has been phased out of nursing education — or so we think.  

Mnemonic “MONA” 

Morphine

As early as 2016, researchers pleaded with academic journals to stop using the MONA acronym as a learning tool (Gouda et al., 2016). Studies show that administrating morphine to patients with a suspected myocardial infarction was associated with more significant tissue damage, worsened reperfusion, and an increased mortality risk (Chen et al., 2018). Another problem with morphine is that it may interact with antiplatelet agents given to prevent further ischemic myocardial tissue damage (Breall & Simons, 2023). Furthermore, suppose your patient becomes sedated from this analgesic. In that case, they cannot tell you if their pain is worsening or if they develop any other symptoms, such as dizziness or shortness of breath.

Oxygen 

Supplemental oxygen administration was the go-to educated guess on nursing school exams. In emergencies, we are always taught to provide oxygen to our patients. However, too much oxygen can be harmful, especially to patients who maintain O2 saturations that are more significant than 94% with ambient air. A 2018 meta-analysis showed that providing oxygen to patients had no increased benefit to reperfusion, decreased mortality risk, or reduced risk of recurrent MI or ischemia (Breall & Simons, 2023). Hyper-oxygenating a patient could cause a vasoconstrictive effect in the coronary arteries and affect tissue repair from the uptick of oxygen free radicals (Gouda et al., 2016). If your patient complains of trouble breathing, check their oxygen saturation and provide oxygen if they develop worsening respiratory status. Oxygen administration is usually indicated when saturation levels are less than 90%-92%.

Nitroglycerin 

While nitroglycerin is a pertinent intervention in ACS management, it should not be given in some cases. Nitroglycerin is a potent vasodilator contraindicated in patients with hypotension, taking phosphodiesterase inhibitors such as Sildenafil, or patients with right-sided heart failure (Breall & Simons, 2023). Nurses should obtain a thorough medical history and closely monitor vital signs before and during nitroglycerin administration. 

Aspirin 

Aspirin administration is the only aspect of MONA that remains well-supported by evidence showing clear health benefits in the ACS setting. Patients should chew 162-325mg of aspirin as soon as possible if they suspect they are having a heart attack (Awtry et al., 2023). Unless the patient has an allergy to aspirin, it should be given to all patients with suspected ACS. Typically, a loading dose of an antiplatelet drug such as clopidogrel or ticagrelor is provided as a dual therapy with aspirin to prevent recurrent MI or stent thrombosis following a percutaneous coronary intervention (Wang & Rao, 2016). Since there is an increased bleeding risk while taking these medications, nurses should monitor their patients closely for overt signs of bleeding or changes in CBC lab values.

Current Acute Coronary Syndrome Recommendations

The most recent ACS guidelines highlight time-sensitive recognition and workup, such as obtaining an ECG and cardiac enzyme labs (Awtry et al., 2023). Administering antithrombotic therapy and anticoagulants such as heparin infusion is crucial in medical management. Extra medications such as beta-blockers or statins may be added for this patient to improve heart function and prevent further damage. The doctors will discuss revascularization strategies best suited for the patient, such as angiography with PCI or medication management (Breall & Simons, 2023).  

The Bottom Line

If you hear this acronym floating around your nursing unit or in the classroom, stop and remember that this is an outdated mnemonic device that is not best practice and is potentially harmful to patients.  

Be mindful of online supplemental learning materials since they could contain obsolete practices. For example, during a Google search of MONA, I found a 2023 online study guide with the MONA mnemonic. As a bedside nurse, if a provider orders morphine, supplemental oxygen, or nitroglycerin in an ACS setting, I would have a discussion and ask for the indication behind giving those medications. Cardiologists should be current on the latest ACS guidelines, but occasionally, you still get a physician who has difficulty adapting to new practices. 

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