EMT Lecture - Cardiac Emergencies

Understanding Cardiac Anatomy and Electrical Pathways

Overview of Cardiac Structure

• The lecture covers cardiology and cardiac emergencies, emphasizing the complexity of the topic despite a brief overview.

• A review of heart anatomy includes atria, ventricles, valves, vessels, oxygenated and deoxygenated blood.

Heart's Electrical System

• The heart generates its own electricity through specialized pathways rather than through blood vessels like coronary arteries.

• The electrical impulse originates from the SA node (Sinoatrial node), which is crucial for initiating heartbeats throughout life.

Impulse Transmission

• The impulse travels from the right atrium to the junction where it meets the ventricles, known as the AV node (Atrioventricular node).

• The SA node functions like a starting pitcher in baseball, sending impulses at a rate of 60 to 100 beats per minute due to chemical reactions.

Backup Systems in Cardiac Function

• If the SA node fails, backup systems exist: first, the AV node can take over with a reduced rate of 40 to 60 beats per minute.

• In severe cases where both nodes fail, Purkinje fibers can generate impulses at a much lower rate of 20 to 40 beats per minute.

Importance for EMT Training

Understanding Coronary Arteries and Related Conditions

Importance of Coronary Arteries

• The coronary arteries are crucial for supplying blood to the heart muscle, which is essential for its function.

• Blood circulates through the heart's four chambers but does not directly perfuse the heart itself; this is done by the coronary arteries.

• The left ventricle sends oxygenated blood into the aorta, from where it branches off into the coronary arteries.

Overview of Blood Flow and Heart Function

• Understanding preload, afterload, heart rate, and stroke volume is important but may not be tested in EMT training.

• Blood pressure consists of systolic and diastolic measurements; familiarity with these terms is necessary for EMT students.

Coronary Artery Disease (CAD)

• CAD involves issues with the coronary arteries that supply blood to the heart muscle.

• Two key conditions related to CAD are atherosclerosis (fatty deposits in artery walls) and arteriosclerosis (hardening of arteries due to calcium buildup).

Definitions and Differences

• Atherosclerosis refers specifically to fatty deposits inside arterial lumens, while arteriosclerosis involves loss of elasticity in arteries.

• For EMT purposes, both terms can be used interchangeably despite their scientific differences.

Implications of Blockages

• Blockages can lead to reduced blood flow; patients may experience angina or myocardial infarction (MI), commonly referred to as a heart attack.

• Infarction occurs distal to a blockage where tissue death happens due to lack of perfusion.

Acute Coronary Syndrome (ACS)

• ACS encompasses various syndromes associated with CAD; it represents an urgent medical condition requiring immediate attention.

Understanding Chest Pain: Differentiating Angina and Myocardial Infarction

Key Concepts in Chest Pain Assessment

• The term "pectoris" refers to pain in the chest, which is crucial for understanding conditions like angina and myocardial infarction (MI). It's important to differentiate between these two during assessments.

• Angina can mimic heartburn but is fundamentally different; while heartburn is a gastrointestinal issue, angina represents temporary blockage of blood flow that resolves with rest or nitroglycerin.

• The primary complaint associated with MI is chest pain. However, the context of the call (e.g., EMT reports) may not always indicate true severity until further evaluation occurs on-site.

Evaluating Patient Symptoms

• Upon arrival at a scene, it's essential to reassess the patient's condition rather than relying solely on prior assessments made by EMTs. This includes confirming where the patient feels pain.

• Patients often describe their chest discomfort as pressure rather than pain. This distinction can be critical; descriptions like "a weight on my chest" may indicate more severe underlying issues.

• When patients report pressure instead of pain, it could signal an impending myocardial infarction. Such descriptions should prompt immediate concern and further investigation.

Recognizing Signs of Severity

• Crushing chest pain described as pressure can also lead to referred pain in areas such as shoulders or jaws. These symptoms are significant indicators for diagnosis but require lab work for confirmation.

• A feeling of impending doom expressed by patients can be a critical sign of a serious condition like MI. Observing how patients articulate their feelings about their health can provide vital clues.

• Denial of severity is common among patients experiencing cardiac events; many downplay symptoms due to fear or embarrassment, complicating timely medical intervention.

Physical Indicators and Contextual Factors

• Common signs such as cool, pale, diaphoretic skin may suggest shock but are not exclusive indicators of any single condition; they require careful interpretation within broader clinical contexts.

• There are no unique signs that definitively point to one disease; many symptoms overlap across various conditions, necessitating comprehensive evaluations by healthcare professionals.

Understanding Myocardial Infarction Symptoms

Preload and Afterload in Heart Function

• The discussion begins with the importance of preload and afterload in heart function, particularly after physical activity. Blockages or clots can hinder blood return to the heart, leading to symptoms.

Angina vs. Myocardial Infarction (MI)

• Angina may be alleviated with rest, unlike myocardial infarction (MI), where symptoms persist despite resting. This distinction is crucial for diagnosis.

Levine's Sign

• The "Levine sign," named after a doctor who observed patients clutching their left chest during an MI, is highlighted as a key indicator of this condition.

Shortness of Breath and Emotional Distress

• Shortness of breath can occur following physical or emotional distress; understanding a patient's life context is essential for accurate assessment.

Atypical Presentations of MI

• Certain groups may not exhibit typical MI signs:

• Diabetics

• Postmenopausal women

• Elderly individuals (both men and women).

Recognizing Non-Traditional Symptoms

Case Studies Highlighting Atypical Symptoms

• An anecdote about a postmenopausal woman feeling "not right" led to discovering she was having an MI, emphasizing the need for vigilance even without classic symptoms.

• Another case involved a male patient who typically did not complain but had significant blockages discovered through careful evaluation despite negative initial tests.

Importance of Clinical Judgment

• Clinicians must rely on gut feelings and comprehensive assessments when patients present atypically, as critical conditions can exist without obvious signs.

Blood Pressure Considerations During MI

Blood Pressure Normals in MI Patients

• Most patients experiencing an MI will have normal blood pressure readings unless it’s an inferior wall MI. Understanding these nuances aids in proper diagnosis and treatment planning.

Monitoring Protocol During Emergencies

Understanding Oxygen Administration Protocols

Current Guidelines for Oxygen Delivery

• New York State protocols recommend administering oxygen based on pulse oximetry readings, specifically if the patient's O2 levels are higher than before.

• Medics should allow patients to choose their position for comfort, especially if they prefer lying down due to symptoms related to coronary artery blockage.

Patient Interaction and Symptoms

• The importance of understanding patient reluctance to go to the hospital despite experiencing severe symptoms is highlighted.

• Increasing oxygen saturation can help push oxygen through blockages in coronary arteries, potentially improving patient outcomes.

Medications and Treatments in Cardiac Emergencies

Administering Aspirin and Nitroglycerin

• Requesting Advanced Life Support (ALS) is crucial; medics can administer aspirin (324 mg) to prevent further clot development.

• If a patient has nitroglycerin at home and meets specific criteria (blood pressure > 120 systolic), one dose can be given sublingually every 2–3 minutes.

Recognizing Angina Pectoris

• Angina pectoris is defined as chest pain; it’s essential not to dismiss this symptom lightly, as it could indicate serious conditions.

• Chest pain must always be taken seriously in EMS; jokes or casual remarks about such symptoms are inappropriate.

Differentiating Between Angina and Myocardial Infarction

Diagnostic Challenges

• Blood tests for troponin levels are critical in diagnosing myocardial infarctions (MI); elevated levels indicate heart damage.

• EKG results show that only about 50% of MIs will present with abnormalities on an EKG, complicating field diagnosis.

Case Study: Real-Life Application

• A case study illustrates a patient with chest pain who initially showed no signs of MI but later was diagnosed with a significant cardiac event after further evaluation at the hospital.

Protocol Adherence During Emergency Calls

Treating Chest Pain as an Emergency

• All complaints of chest pain should be treated as potential MIs until proven otherwise; medics must act decisively regardless of the patient's history or previous diagnoses.

Importance of Patient Safety

Understanding Pulmonary Edema and High Blood Pressure Management

Overview of Pulmonary Edema

• Pulmonary edema is characterized by fluid accumulation in the lungs, often due to heart failure. It can lead to severe respiratory distress.

• Key symptoms include extreme difficulty breathing, chest pain, and abnormal lung sounds known as "rails," indicating fluid presence in the lungs.

• In advanced cases, patients may exhibit pink frothy sputum, a sign of significant fluid backup affecting lung function.

Emergency Response for Pulmonary Edema

• Immediate intervention involves sitting the patient upright and administering oxygen through a CPAP (Continuous Positive Airway Pressure) device to alleviate breathing difficulties.

• Patients with pulmonary edema often present with dangerously high blood pressure readings, sometimes exceeding 260/140 mmHg.

Hypertensive Emergencies

• It's crucial to differentiate between high blood pressure without other symptoms versus those presenting with respiratory distress or chest pain.

• Historically, emergency responders would administer medications for high blood pressure in the field; however, this practice was found to be harmful rather than beneficial.

Current Practices in Managing High Blood Pressure

• If a patient presents only with elevated blood pressure but no other complaints (e.g., clear lungs), it may not warrant immediate emergency intervention.

• Long-term high blood pressure poses serious health risks such as stroke or aneurysm; thus monitoring and management are essential.

Introduction of CPAP for BLS Use

• The use of CPAP has been approved for Basic Life Support (BLS), allowing first responders to provide immediate assistance before medics arrive.

• Proper application of CPAP requires a tight seal on the patient's face and may necessitate high levels of oxygen flow (15–25 liters).

Patient Interaction During Treatment

• It’s vital that patients using CPAP remain conscious and cooperative; explaining its benefits can help ease discomfort during treatment.

CPAP and Consciousness in Pediatric Care

Importance of Consciousness for CPAP Use

• CPAP (Continuous Positive Airway Pressure) can be effectively used on conscious children who are sitting up, emphasizing the need to avoid unnecessary medications that could compromise their condition.

• The use of ventilators is not a basic life support (BLS) skill but is common in transport ambulances; training is provided for those working or volunteering in such services.

Understanding Cardiac Arrest Rhythms

• Upon death, various EKG rhythms can be observed; one notable rhythm appears erratic with no discernible pattern, indicating critical conditions.

• Ventricular fibrillation (VF), described as quivering similar to jello, signifies a severe state where the heart's ventricles are not functioning properly.

Defibrillation and Its Purpose

• Patients experiencing ventricular fibrillation are considered clinically dead and require immediate defibrillation to restore normal heart function.

• Using an AED (Automated External Defibrillator) does not "jump-start" the heart but rather aims to stop the chaotic electrical activity causing VF, hoping to revert it back to a sinus rhythm.

Early Signs of Death in Patients