ACS notes

Chapter 32: Critical Care of Patients with Acute Coronary Syndromes

Learning Outcomes

  • Collaborate with the interprofessional team to provide high-quality care for patients with acute coronary syndromes (ACS) that affect perfusion and cause pain.

  • Prioritize evidence-based care for patients with acute coronary syndromes affecting perfusion.

  • Teach patients about lifestyle modifications to reduce modifiable and non-modifiable risk factors for acute coronary syndromes.

  • Educate patients and caregivers about common medications used for treating acute coronary syndromes.

  • Implement nursing interventions to decrease the psychosocial impact of acute coronary events, especially myocardial infarction (MI).

  • Apply knowledge of anatomy and physiology to provide evidence-based nursing care for patients with stable angina, unstable angina, and MI.

  • Utilize clinical judgment to prioritize nursing care aimed at promoting perfusion and preventing complications in patients with chest pain.

  • Use laboratory data, signs, and symptoms to prioritize care for patients with acute coronary syndrome.

  • Develop a care plan utilizing quality improvement measures for patients requiring percutaneous or surgical coronary intervention to promote perfusion.

Concepts

  • Priority: Perfusion

  • Interrelated Concept: Pain, not a pain rating 0-10

Review of Coronary Circulation

  • The heart perfuses itself

  • S/S are based on where the blockage is located

  • Atherosclerosis is a fat buildup that affects perfusion

  • Collateral circulation, arterial circulation work together to perfuse around the blockages

Patient History and Physical Examination

  • Assess the nature of chest pain using the OLDCARTS method:

    • Onset

    • Location

    • Duration

    • Characteristics

    • Aggravating factors

    • Relieving factors

    • Treatment or previous episodes

  • Identify potential symptoms:

    • Chest pain in the sternal area (described as tightness, heaviness, or pressure).

    • Pain may radiate to the arm, neck, jaw, shoulder, or back.

    • Related symptoms: Nausea, vomiting, diaphoresis, dyspnea, anxiety, fatigue, palpitations, dizziness, altered mental status.

    • Special attention to demographic groups (e.g., women, aging adults, diabetics)

    • S/S in women: indigestion, choking sensation with exertion, fatigue, SOB, anxiety

    • Diabetics: might have different pain, more neuropathic pain

  • Consider factors in the patient history:

    • History of coronary artery disease (CAD)

    • Sex/gender

    • Age: 17 y/o the plaque starts to build

    • Risk factors: diet, smoking/tobacco use, high cholesterol, lack of physical activity, HTN, diabetes

Physical Examination

  • Assess vital signs and cardiac rhythm.

  • Determine the presence of:

    • Jugular venous distention (JVD)

    • Pulmonary congestion

    • Heart murmurs and gallops.

  • Evaluate for signs of poor cardiac output or cardiogenic shock:

    • Hypotension, hypoperfusion (pale, diaphoresis, cyanosis)

    • Elevated temperature can occur with inflammation

  • Conduct neurologic assessment (not enough blood to the brain) and identify contraindications/allergies for antiplatelet or fibrinolytic therapy.

  • Obtain psychosocial assessment.

    • patients feed off your energy so stay calm and take deep breaths the keep you and the patient calm.

Laboratory Assessment

  • Troponin T or Troponin I:

    • Sensitive serum biomarkers for myocardial injury.

    • Levels rise within 2-24 hours with myocardial injury and can remain elevated for up to 14 days.

    • Elevations observed in myocardial infarctions, cardiac trauma, heart failure, myocarditis, and pericarditis.

    • Serum levels monitored every 3-6 hours up to three times to rule out myocardial infarction. Done at the bedside

    • Look at the rise and the fall of level to indicate an acute myocardial injury or infarction

      • Chronic elevated levels can be seen that is why we look at the rise and fall, not a single level.

Imaging Studies

  • Chest x-ray: within 30 mins and shows us the media stinum and/or lung issues

  • Thallium scans (nuclear stress test)

  • Echocardiography

  • Contrast-enhanced cardiovascular magnetic resonance (CMR)

  • CT coronary angiography (CTCA)

Other Diagnostics

  • ECG (EKG): priority, within 5-10 mins of arrival

  • Exercise tolerance test (stress test)

  • Cardiac catheterization (percutaneous coronary intervention)

Coronary Artery Disease (CAD): progressive

  • Definition: Narrowing of coronary arteries that impedes blood flow to the cardiac muscle.

  • Etiology: Primarily caused by atherosclerosis.

  • includes chronic stable angina, acute coronary syndromes.

    • Ischemia:

    • Insufficient blood/oxygen supply to meet myocardial demand.

    • Reversible condition.

    • Infarction:

    • Artery is significantly narrowed or completely obstructed.

    • Necrosis (cell death) due to lack of oxygen. Prolonged and decreased perfusion.

    • Irreversible condition.

Angina

  • Definition: "Chest pain" occurs due to a temporary imbalance between oxygen supply and heart's oxygen demand.

  • Precipitating Factors that increase metabolism/demand:

    • Physical exertion

    • Stress

    • Temperature extremes

    • Heavy meals

    • Smoking

Types of Angina

  • Chronic Stable Angina (CSA):

    • Associated with fixed (stable) atherosclerotic plaque.

    • Manifestations: Symptoms occur with physical activity, familiar frequency, duration, and intensity; symptoms are limited in duration (it does’t last very long).

    • Management: Pain relieved with rest or nitroglycerin (NTG), often managed with drug therapy such as aspirin (ASA) antiplatlet (keeps platelets from clumping together), NTG, and statins.

Acute Coronary Syndrome (ACS)

  • Definition: Condition resulting from the rupture of atherosclerotic plaque leading to platelet aggregation, thrombus formation, and vasoconstriction.

Types of ACS:

  • Unstable Angina

  • Acute Myocardial Infarction (AMI)

Unstable Angina

  • Pathophysiology: Reduced coronary perfusion due to atherosclerotic plaque rupture leading to non-occlusive (does NOT completely block the vessel) thrombus formation.

  • Subtypes:

  • New-onset angina: First episode of symptoms.

  • Vasospastic angina (Variant or Prinzmetal angina): Caused by vasospasm; occurs unpredictably, typically at rest.

    • ST segment elevation, relieved after spasm stops

  • Pre-infarction angina: Pain occurs days or weeks prior to a heart attack.

  • Manifestations can occur at rest or with exertion; the increase in episodes (attacks) correlates with greater pain intensity.

  • ST “changes” without elevated cardiac enzymes (troponin) present as inverted T-waves or ST segment depression.

    • We have ischemia showing up on the monitor

    • negative troponin

Myocardial Infarction (MI)

  • Pathophysiology: Rupture of atherosclerotic plaque results in occlusive thrombus formation leading to ischemia, injury, and then necrosis.

Types of MI:

  • Non-ST segment Elevation Myocardial Infarction (NSTEMI)

  • ST segment Elevation Myocardial Infarction (STEMI)

Zones of Injury:

  • Ischemia → Infarction:

    • J Point: Junction between the end of the QRS complex and beginning of the ST segment.

      • Look at this and if it rises 1 mm it is positive for ST elevation.

  • ST Segment: Starts at the J point and ends at the beginning of the T wave.

  • T-wave: Inversion is associated with myocardial ischemia.

NSTEMI Characteristics:

  • Significant sluggish blood flow or poor coronary perfusion of the myocardium

  • ST segment depression and/or T-wave inversion changes on 12-lead ECG.

  • Initial troponin levels may be normal but elevate over 3-12 hours.

  • The changes on ECG AND elevation in troponin indicates myocardial cell death

  • Myocardial damage does not extend through the ventricular wall.

STEMI Characteristics:

  • New ST elevation at the J point in at least two contiguous leads (leads that are clumped together looking at one specific part of the heart) of more than 0.1 ext{mV}.

  • Elevated troponin levels; signifies 100% occlusion of coronary vessels.

    • full thickness of the heart muscle

  • MEDICAL EMRERGENCY!

ECG Interpretation

  • Contiguous Leads: Grouped leads that provide views of specific ischemic or infarcted sections, including:

    • Inferior leads: II, III, aVF

    • Lateral leads: I, aVL, V5, V6

    • Septal leads: V1, V2

    • Anterior leads: V1, V2, V3, V4

      • 2 or more contiguous leads needed for positive

  • 18-Lead: used to see ischemia, make sure this is labeled as such

look at the J point Ischemia and infarction in 2,3, aVF

Ventricular Remodeling Process

  • Pre-MI Stage: Healthy structure with no symptoms of heart failure (HF) but high risk factors.

  • Early MI Stage: Infarct expansion occurs within hours to days post-event.

  • Late MI Stage: Global remodeling take place.

Analysis: Hypothesis Prioritization

  • Acute pain related to imbalance between myocardial oxygen supply and demand.

  • Decreased myocardial tissue perfusion due to interruption of blood flow.

  • Potential for dysrhythmias due to ischemia and ventricular irritability.

  • Risk for heart failure due to left ventricular dysfunction.

Planning and Implementation

Managing Acute Pain

  • Expected Outcome: Patient verbalizes reduced pain due to improved perfusion.

  • Interventions:

    • Comfort positioning

    • Minimize patient movement

    • Provide a calm and quiet environment

    • Focus on decreasing pain

    • Decrease myocardial oxygen demand

    • Increase perfusion

  • Drug Therapy Options:

    • Administration of Oxygen when required (don’t give supplemental oxygen unless needed O2 sat of <90 starting at 4L titrating down)

    • Nitroglycerin (NTG) Sublingually:

    • Increases collateral blood flow, redistributes blood flow toward the subendocardium, dilates coronary arteries, and decreases myocardial oxygen demand by reducing preload and afterload.

    • Administration Protocol:

    • Assess pain and vital signs (every 5 mins); ensure adequate CO and hemodynamic stability.

      • HOLD if systolic is <90 or <30 below baseline, HR <50 or >100, NO pain

    • Ask if taken phosphodiesterase inhibitor in last 12-48 hours (contraindicated)

    • Administer every 3-5 minutes SL up to 3 doses ONLY

    • Titrate effect of NTG

    • Teaching: might tingle or burn, don’t put in the light, needs to be replaced every 6 months, if not relief after 3rd dose call 911, might cause dizziness or HA

    • Morphine IV Push:

    • Used if the patient is unresponsive to NTG; provides pain relief and decreases myocardial oxygen demand, also relaxes smooth muscle and reduces catecholamines (adrenaline). use caution with older/younger patients

Increasing Myocardial Tissue Perfusion

  • Expected Outcome: Achieve adequate cardiac output, normal sinus rhythm, and maintain vital signs within normal limits.

  • Interventions: Focused on restoring perfusion to the injured area of the heart;

  • Drug Therapy: Includes:

    • Antiplatelet Therapy: aspirin 325mg or 4 baby aspirin chewed up

      • Do NOT give with allergy or past GI bleeding (can give rectally if so)

    • Anticoagulation Therapy: Heparin

    • Antihypertensives:

      • Beta blockers

        • decreases workload of heart

        • reduced occurrence of ventricular dysrhythmias

      • ACE inhibitors or Angiotensin receptor blockers (ARBs)

        • given within 48hrs to ACS with evidence of HF

        • reduces chance of ventricular remodeling

      • Calcium Channel Blockers)

        • promotes vasodilation and myocardial perfusion

        • used in chronic stable angina and coronary vasospasm

    • Statin Therapy

    • Reperfusion Therapy through Fibrinolytics (Thrombolytic agents) IV:

      • Clot buster, lise the clot and keeps the coronary artery perfusing

      • used for ST elevation or MI

    • Includes agents like tissue plasminogen activator (tPA, alteplase), Reteplase (activase), and Tenecteplase (TNK) for STEMI patients that cannot undergo timely percutaneous coronary intervention (PCI).

      • PCI best option for patients

    • Requires administering within 12 hours of symptom onset with ST elevation AND if PCI is unavailable within 90 minutes of first medical contact.

    • Onset of symptoms within the prior 12 hours and ECG findings consistent with true posterior MI.

    • Doors to Needle time must be within 30 minutes from ED arrival or onset of chest pain.

Contraindications for Fibrinolytics (Thrombolytics)

Do not give: patients who present more than 24hrs after the onset of symptoms, ST segment depression, unless a true posterior MI is suspected, the is an absolute contraindication

Absolute Contraindications:

  • Prior intracranial hemorrhage

  • Known structural cerebral vascular lesion

  • Known malignant intracranial neoplasm

  • Ischemic stroke within 3 months except for acute ischemic stroke within 3 hours

  • Suspected aortic dissection

  • Active bleeding or bleeding disorders

  • Significant closed-head or facial trauma within 3 months

Relative Contraindications:

  • Severe uncontrolled chronic hypertension at presentation

  • History of chronic severe hypertension (SBP >180)

  • History of ischemic stroke within the past 3 months, dementia

  • Trauma or prolonged (>10mins) CPR recently or major surgery (within 3 weeks)

  • Recent (within 2-4 weeks) internal bleeding

  • Pregnancy

  • Peptic ulcer disease

  • Current use of anticoagulants

  • Noncompressible vascular puncture

    Monitor for Effectiveness of Fibrinolytic

  • Indications the clot has dissolved, and the artery is re-perfused

    • Abrupt cessation of pain or discomfort

    • Sudden onset of ventricular dsyrhythmias    

    • Resolution of ST segment depression/elevation or T wave inversion

    • A peak at 12 hours of markers of myocardial damage

  • Indication of re-occlusion

    • Return of chest pain/discomfort or previous symptoms’

    • Worsening or return of ST segment elevation

Report Immediate Indications of Bleeding
Percutaneous Coronary Intervention (PCI)

  • Aim to restore blood flow to obstructed areas through a percutaneous procedure.

  • Goals: Door to balloon time within 90 minutes for STEMI patients.

  • Assess (allergies, Hx)

    • allergy to contrast dye

    • kidney function

  • Types of interventions:

    • Atherectsomy

    • Angioplasty with stent placement

  • Post-Procedure Monitoring: Check for:

    • Acute vessel closure

    • Bleeding

    • Reactions to contrast dye

    • Hypotension and hypokalemia

    • Dysrhythmias

ACLS: Acute Coronary Syndrome Algorithm

Identifying and Managing Dysrhythmias

  • Desired Outcome: free of dysrhythmias or identify and manage early to prevent complications.

  • Interventions & Monitoring:

    • Identify dysrhythmias

      • bradycardias often linked to ischemia or AV node

      • ventricular irritability

    • Assess hemodynamic status

      • treat if compromised or if increased myocardial oxygen requirements

    • Evaluate for discomfort

Coronary Artery Bypass Graft (CABG) Surgery

  • Definition: Surgical procedure where occluded coronary arteries are bypassed.

  • Candidates for CABG:

    • Angina with over 50% occlusion of the left main coronary artery that cannot be stented.

    • Unstable angina due to severe 2-vessel disease or occlusion.

    • Moderate 3-vessel or small vessel disease.

    • Any vessel unsuitable for PCI.

    • Heart failure or valve disease.

    • Acute MI with cardiogenic shock.

    • Ischemia or impending MI after angiography for PCI

Preoperative Care

  • Confirm allergies, perform diagnostic tests, type and cross-match blood supplies, and review medications.

  • Prepare for physical procedures like incisions, ETT/ventilators, chest tubes, endotracheal tubes, urinary catheters, and pacemaker wires.

  • Educate the patient about splinting incisions, deep breathing exercises, expected pain, and early ambulation, arms/leg exercises, anxiety id common.

Postoperative Care

  • Implement sterile technique for dressing changes and connect mediastinal tubes to water-seal drainage systems.

  • Monitor heart for signs of dysrhythmias/ pacer wires, manage them, and report any identified CABG complications such as:

    • Fluid and electrolyte imbalance and perform frequent checks on serum electrolytes.

      • edema is common

      • serum electrolytes may be low

      • check frequently

    • Hypotension and conditions that compromise cardiac output.

      • r/t collapsed coronary graft, hypovolemia, or vasodilation

      • report to provider if pt activity includes

        • decreased SBP >20

        • 20 beats/min change in HR

        • c/o dyspnea, chest pain

    • Hypothermia management protocols at temperatures below 96.8°F.

      • re-warm at a rate no faster the 1.8 degrees F/hr

      • promotes vasoconstriction and HTN

    • Hypertension

      • SBP >140-150

      • promotes leakage for suture lines and increased bleeding

CABG Complications Monitoring

  • Bleeding: expected, measure drainage at least hourly, report if over 150mL/hr or abrupt cessation of previously heavy drainage

  • Cardiac Tamponade: Check for Beck's Triad symptoms including hypotension, JVD but clear lung sounds, and distant but muffled heart sounds.

  • Neurological Assessments: Post-anesthesia monitoring and frequent checks (every 30-60 mins) until anesthesia is warn off then every 2-4 hrs. increased transient neuro deficits in older adults.

    • suspected stroke if: abnormal pupillary response, failure to waken, seizures, absence of sensory or motor fucntion.

  • Anginal Pain: Any sternotomy-related pain is expected, but new anginal symptoms may indicate graft failure.

  • Sternal Wound Infection: Check for postoperative fever, bogginess, redness, and drainage from suture sites.

Care Coordination and Transition Management

  • Post-Discharge Considerations:

    • Ensure the patient has support and is not alone.

    • Assess availability of cardiac rehabilitation and home health services.

      • cardiovascular function

      • coping skills

      • functional ability

      • nutritional status

      • patient understanding of illness and treatment

    • Conduct education on:

      • Risk factor modification

      • Complementary and Integrative Health practices

      • Management of sexual activity post-CABG.

      • Drug therapy

  • Healthcare Resources: Include mentioning organizations like the AHA and Mended Hearts for patient support.

Evaluation: Expected Outcomes

  1. Patient states that pain is alleviated.

  2. Adequate myocardial perfusion is established.

  3. Patient remains free of complications such as dysrhythmias and heart failure.