A client is brought to the emergency department for unrelieved chest pain for 45 minutes. ECG performed by EMS suspects a non-ST elevation myocardial infarction (NSTEMI). Which of the following interventions is most important?

Apply oxygen, administer morphine, and place the client on bed rest with cardiac monitoring.

Have the client chew two aspirin 325 mg each, administer oxygen and bring the crash cart to the bedside.

Administer oxygen, give a dose of nitroglycerin sublingual, and follow with a nonsteroidal anti-inflammatory.

Begin a heparin drip, administer oxygen, and call the lab for stat troponin levels.