Page 18 - JSOM Fall 2021

consumption. The routine use of morphine for pain control is daily as long as the systolic blood pressure is above 90 to
not recommended since this has been shown to increase the risk 100mmHg
34
of mortality in ACS. Nitroglycerin, a vasodilator, opens blood OR
vessels to improve blood flow, treating angina symptoms, such
as chest pain or pressure that happens when there is not enough 2. Enalapril – initial dose 2.5mg PO daily increased up to
blood flowing to the heart. Nitroglycerin dilates coronary arter- 20mg PO twice daily
ies and relaxes vascular smooth muscles, resulting in decreased OR
preload/afterload and decreased myocardial oxygen demand.
3. Lisinopril – initial dose 2.5mg PO daily increased to a max-
Nitroglycerin imum of 10mg PO daily
1. Initial dose of 0.3–0.4mg sublingually every 5 minutes OR
for 3 doses; afterwards, an intravenous infusion may be
considered. 4. Losartan – 25-50mg PO once daily depending on initial
2. If a nitroglycerin IV infusion is administered, start at 5– blood pressure
10mg/minute and titrate as needed to relieve anginal symp-
toms in increments of 5mg/min every 5–10 minutes up to Other Therapies
20mg/min; if angina persists at a dose of 20mg/min, then If indicated, continue to utilize proton pump inhibitors. Non-
increase the dosage by 10–20mg/min every 3–5 minutes to a steroidal anti-inflammatory drugs (NSAIDs), on the other
maximum dose of 400mg/min. hand, should be avoided in these patients due to their increased
3. Nitroglycerin is contraindicated in patients who have a risk of adverse cardiovascular events and the increased risk of
systolic blood pressure < 100mmHg, who have used phos- bleeding when combined with the other mainstay treatments
phodiesterase inhibitors in the last 24 hours, or who have of ACS, such as antiplatelet and anticoagulant therapy. Rou-
evidence of inferior STEMI on ECG. tine use of blood transfusion in the setting of ACS is associated
with increased mortality. 13,36,37 It is recommended to avoid
β-Blockers transfusion unless the hemoglobin level is < 8 g/dL.
β-Blockers block sympathetic stimulation and decrease the
heart rate. They have been shown to decrease early develop-
ment of lethal ventricular dysrhythmias as well as improve Complications to Therapy
long-term left ventricular remodeling. Although the Ameri- Bleeding Complications
can Heart Association and American College of Cardiology Bleeding complications are likely to be rare, but they may be en-
recommend that β-blockers be initiated in the first 24 hours countered and should be closely watched. Neurological checks
of NSTEMI, there have been studies that show early admin- should occur every 15 minutes for the first hour and then 30
istration of β-blockers in the ED was associated with higher minutes for the next 6 hours to monitor for intracranial bleed-
rates of shock or death than later administration. Initiate ing. Normotension should be strived for while SBP > 160mmHg
35
this medication after the patient has been hospitalized in ei- should be avoided. Once life-threatening bleeding is identified,
ther the Role 2 or Role 3. β-Blockers should be withheld in stop all antiplatelet agents, anticoagulants, and fibrinolytics.
patients with systolic blood pressure < 100mmHg, heart rate Specific reversal therapies unique to life-threatening bleeding
38
< 60 beats per minute, evidence of pulmonary edema, second- due to thrombolysis are listed below. In the case of suspected
or third-degree heart block, severe reactive airway disease, or intracranial bleeding, obtain an emergent CT of the head and
elevated risk of cardiogenic shock. consult neurosurgery if an intracranial bleed is actually present.

1. Metoprolol tartrate (immediate release) – 12.5mg PO every 1. Administer cryoprecipitate – 10 units IV
6–12 hours 2. Administer tranexamic acid (TXA) – 10–15mg/kg IV
3. Stop all antiplatelets, anticoagulants, and fibrinolytics
OR
2. Metoprolol succinate (extended release) – 25–50mg PO
once daily Complications Associated With MI
There are both early and late complications associated with
OR
MI. Early complications will be the focus here as these are the
3. Atenolol – 50–100mg PO every 12–24 hours ones likely to be seen in the deployed setting during the initial
hours to days of treatment.
ACE Inhibitors and ARBs
Angiotensin-converting enzyme (ACE) inhibitors that are ini- Cardiogenic Shock
tiated within 24 hours to 16 days after an acute MI show im- Cardiogenic shock is best defined as SBP < 90mmHg for 30
proved patient survival as well as improved left ventricular minutes or SBP > 90 mmHg on vasopressors with evidence of
ejection fraction. ACE inhibitors are contraindicated in sys- end-organ damage from a cardiovascular origin. The patient
tolic blood pressure < 100mmHg, history of bilateral renal ar- may have evidence of pulmonary edema (worsening dyspnea,
tery stenosis, hyperkalemia, or prior worsening renal function crackles, worsening chest x-ray) or evidence of peripheral hy-
with ACE inhibitors. It is reasonable to administer angiotensin poperfusion (weak pulses, cold extremities). Listed below are
receptor blockers (ARBs) in patients who cannot tolerate ACE the vasopressor/inotropic agents that should be utilized in this
inhibitors. situation. 39

1. Captopril – initial dose 6.25mg PO, which is increased at 6- 1. Norepinephrine (preferred first-line agent) – 5–20mg/min IV.
to 8-hour intervals to a maximum of 50mg PO three times Start at 5mg/min and increase by 2–5mg/min q15 minutes.

16 | JSOM Volume 21, Edition 3 / Fall 2021