Mr. S. was admitted to the emergency department (ED) by the
emergency medical service with a complaint of sudden onset of substernal chest
pain while he was mowing his lawn. The paramedics placed Mr. S. on oxygen at 2
L/min by nasal cannula. They started an 18-gauge intravenous (IV) line in his
left antecubital area with normal saline at keep open rate. They gave Mr. S.
aspirin and three sublingual nitroglycerin tablets every 5 minutes en route.
Mr. S. states that his pain has gone from a 7, on a scale from 0 to 10, to a 3.
The ED nurse places Mr. S. on the cardiac monitor and notes
that he is in sinus rhythm with frequent premature ventricular contractions
(PVCs). The paramedic states that Mr. S. was diaphoretic, cool, and clammy on
arrival of the emergency medical service at the scene. Mr. S. is warm and less
clammy, although he is still quite pale. His blood pressure is 154/88 mm Hg,
pulse is 95 beats per minute, and respiratory rate is 24 breaths per minute and
nonlabored.
While awaiting the arrival of the ED physician to examine
Mr. S., the nurse starts a second IV line, gives Mr. S. another nitroglycerin
tablet, and proceeds to obtain a brief history from Mr. S.
Mr. S. is a 63-year-old white man, 220 lb, and he has been
married for 41 years. He is hypertensive and diabetic, and he smokes 11⁄2
packs of cigarettes per day. He is allergic to penicillin. While the nurse is
obtaining the history from Mr. S., the monitor alarms. She identifies the
rhythm as ventricular fibrillation and begins cardiopulmonary resuscitation.
The code team arrives, and Mr. S. is defibrillated with 200 J using the
biphasic defibrillator. Following defibrillation, his rhythm is regular sinus
with frequent PVCs. His blood pressure is 92/56 mm Hg, his pulse is thready,
and he is diaphoretic. His pupils are 4 mm, equal and reactive. His respiratory
rate is 16 breaths per minute and shallow, and his oxygen saturation is 92%. He
has developed crackles in his lower and middle lung fields bilaterally. He is
not fully awake at this time, but he is moving all his extremities. A 150-mg IV
bolus of amiodarone is given over 10 minutes, and an infusion is started at 1
mg/min. Emergency laboratory tests and arterial blood gases are ordered, along
with a 12-lead electrocardiogram (ECG). A request for an emergency consultation
is placed to the cardiologist.
A 12-lead ECG shows ST elevation in leads V2, V3,
and V4. Mr. S. is diagnosed with an acute anterior myocardial
infarction. His oxygen is increased to 6 L/min by nasal cannula. Based on these
assessment and study results, tissue plasminogen activator (t-PA) is
administered.
Questions
1. What do Mr. S’s cardiac enzyme values indicate about the
time and extent of his myocardial infarction?
2. What would you expect his repeat troponin levels to be at
the following times after his heart attack? a. At 8 hours b. At 12 hours
3. What complications may be anticipated for Mr. S. related
to the infusion of t-PA? What parameters would the nurse need to monitor?
4. What assessments would indicate that the t-PA was
effective?
5. What risk factors for CAD should be addressed before Mr.
S.’s discharge to reduce his risk of another MI?