Chapter 16: Cardiovascular Emergencies

Nitroglycerin

: Relaxes the muscle of blood vessel walls Dilates coronary arteries Increases blood flow and the supply of oxygen to the heart muscle Decreases the workload of the heart

Ventricular fibrillation (V fib)

: Disorganized, ineffective quivering of the ventricles No blood is pumped through the body, and the patient usually becomes unconscious within seconds. The only way to convert this dysrhythmia is to defibrillate the heart to restore a normal rhythmic beat. Defibrillation is highly successful if delivered within the first few minutes of sudden death. If a defibrillator is not immediately available, initiate CPR until the defibrillator arrives. Chances of survival diminish approximately 10% each minute until defibrillation is accomplished.

occlusion

A blockage, usually of a tubular structure such as a blood vessel.

congestive heart failure (CHF)

A disorder in which the heart loses part of its ability to effectively pump blood, usually as a result of damage to the heart muscle and usually resulting in a backup of fluid into the lungs.

artifact

A tracing on an ECG that is the result of interference, such as patient movement, rather than the heart's electrical activity

External defibrillator vests

A vest with built-in monitoring electrodes and defibrillation pads, which is worn by the patient under his or her clothing The vest is attached to a monitor worn on a belt or hung from a shoulder strap. The monitor provides alerts and voice prompts when it recognizes a dangerous rhythm and before a shock is delivered. Unlike the implantable defibrillator, this device uses high-energy shocks similar to an AED, so avoid contact with the patient if the device warns that it is about to deliver a shock. Blue gel under large defibrillation pads indicates that the device has already delivered at least one shock. If the patient is in cardiac arrest, the vest should remain in place while CPR is being performed unless it interferes with compressions. If you need to remove the vest, simply remove the battery from the monitor and then remove the vest. Any patient who is wearing a device that has already delivered a shock should be transported to the hospital for further evaluation.

Good perfusion requires three primary components:

A well-functioning heart, or "pump" When the heart beats too rapidly, there is not enough time between contractions for the heart to refill completely. When the heart beats too slowly, the volume of blood circulated per minute decreases due to the slow pulse rate. An adequate volume of "fluid" (blood) If there is blood loss through hemorrhage, the reduced volume will limit the amount of tissue that can be perfused. The blood must be carried in a properly sized "container." If the blood vessels dilate, increasing the size of the container, and the volume of fluid remains the same, there will not be enough blood to fill the blood vessels and perfusion will be reduced

Cardiac Arrest

AEDs deliver electrical energy from one pad to the other (and then back to the first pad) to electrically stun the heart and allow it to resume normal function. The factors involved in the defibrillation include voltage, current, and impedance. Most AEDs are set up to adjust the voltage based on the impedance to deliver the proper amount of current, which causes the cells to defibrillate. The AED is programmed to recognize rhythms that require defibrillation to correct, most commonly ventricular fibrillation. Advantages of an AED include: Extremely accurate Fast Delivers the most important treatment for a patient in ventricular fibrillation: an electrical shock It can be delivered within 1 minute of your arrival at the patient's side Easy to operate The shock can be given through remote, adhesive defibrillator pads. The pad area is larger than manual paddles, so the transmission of electricity is more efficient. Although the cardiac rhythm of all patients in cardiac arrest should be analyzed with an AED, some do not have shockable rhythms. Asystole (flatline) indicates that no electrical activity remains. Pulseless electrical activity refers to a state of cardiac arrest that exists despite an organized electrical complex. In both cases, initiate CPR as soon as possible beginning with chest compressions.

Cardiogenic shock is more commonly found in an

AMI that affects the inferior and posterior regions of the left ventricle of the heart because this provides circulation to the majority of the body. Can occur immediately or as late as 24 hours after the onset of the AMI

Acute Myocardial Infarction

About 30 minutes after blood flow is cut off, some heart muscle cells begin to die. After about 2 hours, as many as half of the cells in the area can be dead. In most cases, after 4 to 6 hours, more than 90% will be dead. In many cases, opening the coronary artery with "clot-busting" (thrombolytic) medications or angioplasty (mechanical clearing of the artery) can prevent permanent damage to the heart muscle if done within the first few hours after the onset of symptoms.

Integrating the Automated External Defibrillator and Cardiopulmonary Resuscitation

An AED is not very complex, but it may not be able to distinguish other movements from ventricular fibrillation. To avoid this, apply the AED only to pulseless, unresponsive patients and stay clear of the patient while the AED is analyzing the heart rhythm and delivering shocks. Stop CPR and let the AED do its job

Consequences

An AMI can have three serious consequences: Sudden death Cardiogenic shock Congestive heart failure

Dysrhythmia

An abnormality of heart rhythm

Congestive heart failure (CHF) can occur:

Any time after a myocardial infarction In the setting of heart valve damage As a consequence of long-standing high blood pressure

Pathophysiology; Atherosclerosis

As a person ages, cholesterol is deposited. The lumen of the artery narrows. As the cholesterol deposits grow, calcium deposits can form as well. The inner wall of the artery becomes rough and brittle with atherosclerotic plaques. Damage to the coronary arteries may become so extensive that they cannot accommodate increased blood flow during times of maximum need.

Nitroglycerin comes in several forms:

As a small white tablet, placed sublingually As a spray, also taken sublingually As a skin patch applied to the chest

If you suspect your patient is experiencing a hypertensive emergency:

Attempt to make him or her comfortable and monitor the blood pressure regularly. Position the patient with the head elevated. Transport rapidly to the ED. Consider ALS assistance.

Cardiac assistive devices include:

Automatic implantable cardiac defibrillators External defibrillator vests Left ventricular assist devices

History Taking

Begin by asking questions about the current situation. Determine whether the patient is experiencing chest pain or discomfort and whether there are any other signs and symptoms. Determine whether the patient is having respiratory difficulty, because this is common among patients with chest pain. If the patient is experiencing dyspnea, find out whether it is related to exertion and to the patient's position. Often, patients with chest pain experience worse difficulty breathing when they are lying down. Determine whether the dyspnea is continuous or if it changes, especially with deep breathing. Note whether the patient has a cough and whether the cough produces sputum. Ask about other signs and symptoms that are commonly found, such as: Nausea and vomiting Fatigue Headache Palpitations (a feeling of the heart skipping a beat or racing) Ask about any trauma the patient might have experienced during the last few days. Record your findings, including pertinent negatives.

Primary Assessment

Begin by determining whether the patient is responsive. If the patient is unresponsive and is not breathing, begin CPR, starting with chest compressions, and call for an AED. Consider calling for ALS backup. After you have formed a general impression, assess airway and breathing. Some episodes of cardiac compromise may produce dizziness or syncope. Consider the possibility of a spinal injury from a fall. Assess the patient's breathing to determine if it is adequate to provide enough oxygen to an ailing heart. Listen for abnormal breath sounds. Apply pulse oximetry. If the patient is having chest pain and their oxygen saturation is less than 95%, administer oxygen at 4 L/min via a nasal cannula. If they do not improve quickly, increase the oxygen concentration. Apply a nonrebreathing mask at 15 L/min. The goal is to maintain the oxygen saturation level between 95% and 99%. If the patient is not breathing or has inadequate breathing, ensure adequate ventilations with a bag-valve mask (BVM) and 100% oxygen. Patients experiencing pulmonary edema may require positive-pressure ventilation with a BVM or CPAP. Assess circulation. Determine the rate and quality of the patient's pulse. Assess skin condition, color, moisture, and temperature, as well as the capillary refill time. Consider treatment for cardiogenic shock early to reduce the workload of the heart. Place the patient in a comfortable position, usually sitting up and well supported. Provide reassurance. Make a transport decision based on whether you were able to stabilize life threats during the primary assessment.

When these adaptations can no longer make up for the decreased heart function...

CHF eventually develops. Blood backs up in the pulmonary veins. When the pressure in the capillaries exceeds a certain level, fluid (mostly water) passes through the walls of the capillary vessels and into the alveoli (pulmonary edema). It may occur suddenly, as in an AMI, or slowly over months, as in chronic CHF. If the right side of the heart is damaged, fluid collects in the body, often showing up as swelling in the feet and legs.

Automated External Defibrillation Maintenance

Check your AED daily at the beginning of each shift. Exercise the battery as often as the manufacturer recommends. Ask the manufacturer for a checklist of items that should be checked daily, weekly, or less often. An error can also occur when the AED is applied to a responsive patient with a rapid heart rate. Most AEDs identify a regular rhythm faster than 150 or 180 beats/min as ventricular tachycardia, which should be shocked. Sometimes, however, a patient has another heart rhythm that should not be shocked but that is fast enough to confuse the computer. To avoid this problem, apply the AED only to unresponsive patients with no pulse.

The major controllable factors are:

Cigarette smoking High blood pressure Elevated cholesterol level Diabetes Lack of exercise Obesity

ALS and postarrest care This refers to:

Continuing ventilation at less than 12 breaths/min to achieve an ETCO2 of 35 to 40 mm Hg Maintaining oxygen saturation between 94% and 99% Assuring blood pressure is above 90 mm Hg Maintaining glucose levels in the patient who is hypoglycemic Cardiopulmonary and neurologic support at the hospital Other advanced assessment techniques and interventions as indicated

The parasympathetic nervous system

Directly opposes the sympathetic nervous system Slows the heart and respiratory rates, constricts blood vessels in the muscles, and dilates blood vessels in the digestive system

Emergency Medical Care for Cardiac Arrest: Preparation

Do not defibrillate a patient who is in pooled water. Electricity follows the path of least resistance; instead of traveling between the pads and through the patient's heart, it will diffuse into the water. You can defibrillate a soaking wet patient, but try first to dry the patient's chest. Do not defibrillate someone who is touching metal that others are touching. Remove nitroglycerin patches from a patient's chest and wipe the area with a dry towel before defibrillation to prevent ignition of the patch. It is helpful to shave a hairy patient's chest before pad placement to increase conductivity. Determine the nature of illness and/or mechanism of injury. If the incident involves trauma, consider spinal immobilization as you begin the primary assessment. If you suspect that the patient may be in cardiac arrest, discuss who will perform which resuscitation responsibilities prior to arrival on the scene. Preparation tasks should be done concurrently, so that time to defibrillation is minimized.

Scene Size-up

Do not let your guard down on medical calls. Always ensure that the scene is safe for all. Look for and address any hazards. Determine the necessary standard precautions and whether you will need additional resources. Identify the nature of illness. Use the information you get from the dispatcher, clues at the scene, and comments of bystanders or family members to begin to develop an idea about the type of problem your patient might be experiencing. For patients with cardiac problems, clues often include a report of chest pain, difficulty breathing, or sudden loss of consciousness.

Circulation

During physical exertion or stress, the myocardium requires more oxygen. The stroke volume is the volume of blood ejected with each ventricular contraction. In the normal heart, increased oxygen demand of the myocardium itself is supplied by dilation (widening) of the coronary arteries, which increases blood flow. These arteries start at the first part of the aorta, just above the aortic valve. The right coronary artery supplies blood to the right atrium; right ventricle; and, in most people, the bottom part, or inferior wall, of the left ventricle. The left coronary artery supplies blood to the left atrium and left ventricle, and it divides into two major branches just a short distance from the aorta.

Operator errors include:

Failing to apply the AED to a patient in cardiac arrest Not pushing the analyze or shock buttons when the machine advises you to do so Pushing the power button instead of pushing the shock button when a shock is advised

The three most common errors in using certain AEDs are:

Failure of the machine to shock fine V fib Applying the AED to a patient who is moving, squirming, or being transported Turning off the AED before analysis or shock is complete

Give oxygen, reassessing saturation levels regularly.

For patients with mild dyspnea, use a nasal cannula. Patients with more serious respiratory difficulty may require a nonrebreathing mask. Use a BVM or another positive-pressure ventilation device on a patient who is unconscious or in obvious respiratory distress. Alternatively, consider CPAP depending on local protocol.

If the patient is responsive, obtain the SAMPLE history and ask the following questions specific to a cardiovascular emergency:

Have you ever had a heart attack? Have you been told that you have heart problems? Have you ever been diagnosed with angina, heart failure, or heart valve disease? Have you ever had high blood pressure? Have you ever been diagnosed with an aneurysm? Do you have any respiratory diseases such as emphysema or chronic bronchitis? Do you have diabetes or have you ever had any problems with your blood sugar? Have you ever had kidney disease? Do you have any risk factors for coronary artery disease, such as smoking, high blood pressure, or high-stress lifestyle? Is there a family history of heart disease? Do you currently take any medications?

If the patient is taking medications, determine whether they are prescribed, over-the-counter, and/or recreational drugs.

If the patient has had a heart attack or angina before, ask whether the pain is similar. Ask about allergies because the patient will very likely be given medication in the hospital. When you ask about medical conditions, ask whether the patient takes medications for any other condition he or she identifies. Ask about the last oral intake. Ask about any home remedies the patient might have used.

Unstable angina is characterized by pain or discomfort in the chest of coronary origin that occurs in response to progressively less exercise or fewer stimuli than ordinarily required to produce angina.

If untreated, it can lead to AMI.

Cardiac Arrest During Transport

If you are traveling to the hospital with an unconscious patient, check the pulse at least every 30 seconds.

Heart Surgeries

In a coronary artery bypass graft, a blood vessel from the chest or leg is sewn directly from the aorta to a coronary artery beyond the point of the obstruction. Patients who have had a bypass graft will have a long surgical scar on the chest. Percutaneous transluminal coronary angioplasty aims to dilate, rather than bypass, the coronary artery. In this procedure, usually called an angioplasty or balloon angioplasty, a tiny balloon is attached to the end of a long, thin tube. The tube is introduced through the skin into a large artery, usually in the groin, and then threaded into the narrowed coronary artery, with radiographs serving as a guide. Once the balloon is in position, it is inflated. The balloon is then deflated, and the tube is removed from the body. Sometimes, a metal mesh cylinder (stent) is placed inside the artery instead of or after the balloon. The stent is left in place permanently to help keep the artery from narrowing again. Pacemakers deliver an electrical impulse through wires that are in direct contact with the myocardium. The generating unit is placed under a heavy muscle or a fold of skin. Typically resembles a small silver dollar under the skin in the left upper portion of the chest If a pacemaker does not function properly, the patient may experience syncope, dizziness, or weakness because of an excessively slow heart rate. A patient with a malfunctioning pacemaker should be promptly transported to the ED. When an AED is used, the pads should not be placed directly over the pacemaker.

Anginal pain is commonly described as crushing, squeezing, or "like somebody standing on my chest."

It is usually felt in the midportion of the chest, under the sternum, but can radiate to the jaw, the arms (frequently the left arm), the midportion of the back, or the epigastrium (the upper-middle region of the abdomen). The pain usually lasts from 3 to 8 minutes, rarely longer than 15 minutes. It may be associated with shortness of breath, nausea, or sweating. It usually disappears promptly with rest, supplemental oxygen, or nitroglycerin (NTG).

The sympathetic nervous system

Known as the "fight-or-flight" system Makes adjustments to the body to compensate for increased physical activity Speeds up the heart rate, increases respiratory rate and depth, dilates blood vessels in the muscles, and constricts blood vessels in the digestive system

Side effects include:

Low blood pressure Severe headache Changes in pulse rate, including tachycardia or bradycardia Take the patient's blood pressure within 5 minutes after each dose. If the systolic blood pressure is less than 100 mm Hg, do not give more medication.

Aspirin (acetylsalicylic acid) prevents clots from forming or getting bigger.

Low-dose aspirin comes in 81-mg chewable tablets. The recommended dose is 162 mg (two tablets) to 324 mg (four tablets). Be sure to verify that the patient is not allergic to aspirin. Ask if the patient has any history of internal bleeding, such as stomach ulcers, and, if so, contact medical control before giving the patient aspirin.

Automatic implantable cardiac defibrillators

More and more patients who survive cardiac arrest due to ventricular fibrillation have a small automatic implantable cardiac defibrillator implanted. Some patients who are at particularly high risk for a cardiac arrest have them as well. These devices are attached directly to the heart and continuously monitor the heart rhythm, delivering shocks as needed. Treatment should include performing CPR and using an AED if the patient goes into cardiac arrest. Generally, the electricity from an automatic implantable cardiac defibrillator is so low that it will not have an effect on rescuers.

Anatomy and Physiology (continued)

Normal electrical impulses begin in the sinus node in the upper part of the right atrium (also known as the sinoatrial [SA] node). Impulses travel across both atria, stimulating them to contract. Between the atria and the ventricles, the impulses cross a bridge of special electrical tissue called the atrioventricular (AV) node. Here, the signal is slowed for about one- to two-tenths of a second to allow blood time to pass from the atria to the ventricles. The impulses then exit the atrioventricular node and spread throughout both ventricles via the bundle of His, the right and left bundle branches, and the Purkinje fibers, causing the ventricular muscle cells to contract. Automaticity allows a cardiac muscle cell to contract spontaneously without a stimulus from a nerve source. As long as impulses come from the sinoatrial node, the other myocardial cells will contract when the impulse reaches them. If no impulse arrives, the other myocardial cells are capable of creating their own impulses and stimulating a contraction of the heart, although at a generally slower rate.

Signs and Symptoms

Often, the patient is agitated. Chest pain may or may not be present. The patient often has distended neck veins that do not collapse even when the patient is sitting. The patient finds it easier to breathe when sitting up. When the patient is lying down, more blood is returned to the right ventricle and lungs, causing further pulmonary congestion. The patient may have swollen ankles from dependent edema. The patient generally will have high blood pressure, a rapid heart rate, and rapid respirations. The patient will usually be using accessory breathing muscles of the neck and ribs. Skin is usually pale or cyanotic and sweaty. The fluid surrounding small airways may produce rales (crackles), best heard by listening to either side of the patient's chest, about midway down the back. In severe CHF, these soft sounds can be heard even at the top of the lung.

The major risk factors that cannot be controlled are:

Older age Family history of atherosclerotic coronary artery disease Race Ethnicity Male sex

Signs and Symptoms

One of the first signs of shock is anxiety or restlessness as the brain becomes starved for oxygen. The patient may report "air hunger." Think of the possibility of shock when the patient is saying that he or she cannot breathe. As the shock continues, the body tries to send blood to the most important organs (the brain and heart) and away from less important organs, so you may see pale, cool, clammy skin in patients with shock. The pulse rate will be higher than normal. In severe shock, the heart rate usually, but not always, is greater than 120 beats/min. As the shock progresses, the pulses may become irregular and weak. Shock can also present with rapid and shallow breathing, nausea and vomiting, and a decrease in body temperature. As the heart and other organs begin to malfunction, blood pressure falls below normal. A systolic blood pressure less than 90 mm Hg is a late finding that indicates decompensated shock. Do not assume that shock is not present just because the blood pressure is normal (compensated shock).

Common signs of symptoms

One of the most common signs is a sudden severe headache. This may also be a sign of cerebral hemorrhage. Other signs and symptoms include: Strong bounding pulse Ringing in the ears Nausea and vomiting Dizziness Warm skin (dry or moist) Nosebleed Altered mental status Sudden development of pulmonary edema Untreated hypertensive emergencies can lead to a stroke

OPQRST Mnemonic for Asessing Pain

Onset When did the problem begin, and what does the patient think may have caused it? Provocation/palliation Ask what makes the pain or discomfort better or worse. is it positional? Does a deep breath or palpation of the chest make it worse? Did you take anything for it? Quality -As the patient to describe his/her pain. Let the patient use his/her own words to describe what is happening. If the patient unable ot desribe pain. Avoid giving only one option. If the patient cannot answer an open-ended question. then provoke a list of alternatives? Region/Radiation --Ask where the pain is located and whether the pain has spread to another part of the body Severity -Ask the patient to rate pain on a simple scale 0-10. Use it to check whether pain is getting worse Timing -Find out how long the pain lasts when it is present and whether it has been intermittent or continuous

Dissecting Aneurysm

Onset of Pain -Abrupt, without additional symptoms Quality of Pain -Sharp or tearing Severity of Pain -Maximal from onset Timing of Pain -Does not abate once it has started Region -Back is possibly involved, between the shoulder blades Clinical Signs -Blood pressure discrepancy between arms or decrease in a femoral or carotid pulse

AMI ----------------- Onset of Pain Quality of Pain Severity of Pain Timing of Pain Region Clinical Signs

Onset of Pain -gradual, with additional symptoms Quality of Pain -tightness or pressure Severity of Pain -increase with time Timing of Pain --may wax and wane Region -substernal; back is rarely involved Clinical Signs -peripheral pulses equal

AMI Vs Dissecting Aortic Aneurysm

Onset of Pain Quality of Pain Severity of Pain Timing of Pain Region Clinical Signs

After the AED protocol is completed, one of the following is likely:

Pulse is regained (ROSC) No pulse, and the AED indicates that no shock is advised No pulse, and the AED indicates that a shock is advised

Tachycardia:

Rapid beating of the heart, 100 beats/min or more

Ventricular tachycardia :

Rapid heart rhythm, usually at a rate of 150 to 200 beats/min The electrical activity starts in the ventricle instead of the atrium. This rhythm usually does not allow adequate time between beats for the left ventricle to fill with blood, so the patient's blood pressure may fall and the pulse may be lost altogether. The patient may feel weak or light-headed or may even become unresponsive. Most cases of ventricular tachycardia will be sustained and may deteriorate into ventricular fibrillation.

The five links in the chain of survival are:

Recognition of early warning signs and immediate activation of EMS Immediate CPR with emphasis on high-quality chest compressions Rapid defibrillation Basic and advanced EMS ALS and postarrest care This refers to: Continuing ventilation at less than 12 breaths/min to achieve an ETCO2 of 35 to 40 mm Hg Maintaining oxygen saturation between 94% and 99% Assuring blood pressure is above 90 mm Hg Maintaining glucose levels in the patient who is hypoglycemic Cardiopulmonary and neurologic support at the hospital Other advanced assessment techniques and interventions as indicated

Circulation (continued)

Red blood cells (B) carry oxygen to the body's tissues and remove carbon dioxide. Larger white blood cells (A) help to fight infection. Platelets (C), which help the blood to clot, are much smaller than either red or white blood cells. Plasma, a mixture of water, salts, nutrients, and proteins, is the fluid that the cells float in. Systolic blood pressure is the maximum pressure generated in the arms and legs during the contraction of the left ventricle, during systole. As the left ventricle relaxes in diastole, arterial pressure falls. When the left ventricle relaxes, the aortic valve closes and blood flow between the left ventricle and the aorta stops. Diastolic blood pressure is the pressure exerted against the walls of the arteries while the left ventricle is at rest. Pulses felt in the extremities, such as the radial and the posterior tibial, are called peripheral pulses. Pulses near the trunk of the body, such as the femoral and carotid pulses, are known as central pulses.

With a patient with acute myocardial infarction, pay attention to:

Signs and symptoms Pain Physical findings Consequences

Administering Nitroglycerin

Step 1 Obtain an order from medical control. Take the patient's blood pressure. Administer nitroglycerin only if the systolic blood pressure is greater than 100 mm Hg. Administering Nitroglycerin Step 2 Check the medication and expiration date. Ask the patient about the last dose he or she took and its effects. Make sure that the patient understands the route of administration. Prepare to have the patient lie down to prevent fainting. Step 3 Ask the patient to lift his or her tongue. Place the tablet or spray the dose under the tongue (while wearing gloves), or have the patient do so. Have the patient keep his or her mouth closed with the tablet or spray under the tongue until it is dissolved and absorbed. Caution the patient against chewing or swallowing the tablet. Step 4 Recheck the blood pressure within 5 minutes. Record each medication and the time of administration. Reevaluate the chest pain and blood pressure, and repeat treatment if necessary.

Performing Cardiac Monitoring

Step 1 Take standard precautions. Step 2 Explain the procedure to the patient. Prepare the skin for electrode placement Step 3 Attach the electrodes to the leads before placing them on the patient. Step 4 Position the limb electrodes on the patient. Place the leads on the torso if performing continuous monitoring, or on the limbs if you will be acquiring a 12-lead ECG. Step 5 If you plan to obtain a 12-lead ECG tracing, place the chest leads on the chest. Performing Cardiac Monitoring Step 6 Turn on the monitor. Step 7 Record tracings. Step 8 Label each strip.

Performing Defibrillation

Step 1 Take standard precautions. Determine scene safety. Question bystanders. Determine responsiveness. Assess compression effectiveness if CPR is already in progress. If the patient is unresponsive and CPR has not been started yet, begin providing chest compressions and rescue breaths at a ratio of 30 compressions to 2 breaths and a rate of 100 to 120 compressions per minute, continuing until an AED arrives and is ready for use. Step 2 Turn on the AED. Apply the AED pads to the chest and attach the pads to the AED. Stop CPR. If a shock is not advised, perform five cycles (about 2 minutes) of CPR, beginning with chest compressions, and then reanalyze the cardiac rhythm. If a shock is advised, reconfirm that no one is touching the patient and push the Shock button. If at any time the AED advises to check the patient, quickly assess for a carotid or femoral pulse. This should not take longer than 5 to 10 seconds. If you feel a pulse, the patient has experienced ROSC (return of spontaneous circulation). Continue to monitor the patient. Step 3 Verbally and visually clear the patient. Push the Analyze button, if there is one. Wait for the AED to analyze the cardiac rhythm. If no shock is advised, perform five cycles (2 minutes) of CPR and then reanalyze the cardiac rhythm. If a shock is advised, recheck that all are clear, and push the Shock button. After the shock is delivered, immediately resume CPR beginning with chest compressions and remember to switch rescuers. Step 4 After five cycles (2 minutes) of CPR, reanalyze the cardiac rhythm. Do not interrupt chest compressions for more than 10 seconds. Step 5 If shock is advised, clear the patient, push the Shock button, and immediately resume CPR compressions. If no shock is advised, immediately resume CPR compressions and be sure to switch rescuers. After five cycles (2 minutes) of CPR, reanalyze the cardiac rhythm. Repeat the cycle of five cycles (2 minutes) of CPR, one shock (if indicated), and 2 minutes of CPR. Transport and contact medical control as needed.

Lesser factors that play a role in heart disease are:

Stress Excessive alcohol Poor diet

Signs and symptoms Signs and symptoms include:

Sudden onset of weakness, nausea, and sweating without an obvious cause Chest pain, discomfort, or pressure that is often crushing or squeezing and that does not change with each breath Pain, discomfort, or pressure in the lower jaw, arms, back, abdomen, or neck Irregular heartbeat and syncope (fainting) Shortness of breath, or dyspnea Nausea/vomiting Pink, frothy sputum (indicating possible pulmonary edema) Sudden death

Treatment

Take the following steps when treating patients with signs and symptoms of cardiogenic shock: Position the patient comfortably. Some patients will be more comfortable in a semi-Fowler position (head and knees slightly elevated) Patients with low blood pressure may not tolerate a semi-upright position but may be more comfortable and more alert in a supine position. Administer high-flow oxygen. Assist ventilations as necessary. Cover the patient with sheets or blankets as necessary to preserve body heat. Be sure to cover the top of the patient's head in very cold weather, as this is where much heat is lost. Provide prompt transport to the ED.

Common places to feel for a pulse include:

The carotid pulse Can be felt in the neck by placing two fingertips in the center of the throat on the windpipe, and then sliding them towards you into the groove between the trachea and the neck muscle Do not assess both carotid pulses at the same time, as this could greatly reduce blood flow to the brain. The femoral pulse Can be felt in the groin at the crease dividing the lower abdomen from the leg The brachial pulse Can be felt on the medial aspect of the elbow at the level of the crease This is the pulse that you listen for when you take blood pressure. Pulsations also can be palpated on the medial side of the arm midway between the elbow and armpit. The radial pulse Can be felt on the thumb side of the wrist, about one fingerbreadth above the wrist crease The posterior tibial pulse Can be felt on the inside of the ankle, just behind the medial malleolus. The medial malleolus is the bony bump at the bottom end of the tibia The dorsalis pedis pulse Can be felt at the top of the foot This artery is not in the same place in all people. To find the pulse, place your hand across the top of the foot just below the ankle crease.

dependent dedema

The collection of fluid in the part of the body that is closest to the ground is called dependent edema. Chronic dependent edema may indicate underlying heart disease even in the absence of pain or other symptoms.

asystole

The complete absence of all heart electrical activity.

(cardiac arrest).

The death of heart muscle can lead to severe diminishment of the heart's ability to pump or cause it to stop completely

Anatomy and Physiology

The heart is divided down the middle into left and right by a wall called the septum. Each side of the heart has an atrium (upper chamber) to receive incoming blood, and a ventricle (lower chamber) to pump outgoing blood. Blood leaves each of the four chambers through a one-way valve. These valves keep the blood moving through the circulatory system in the proper direction. The aorta receives the blood ejected from the left ventricle and delivers it to all the other arteries. The right side of the heart receives deoxygenated blood from the veins. As the blood reaches the lungs, it receives fresh oxygen from the alveoli and carbon dioxide waste is removed from the blood and moved into the alveoli. The blood then returns to the heart through the pulmonary veins. The left side of the heart receives oxygenated blood from the lungs through the pulmonary veins. Blood enters the left atrium and then passes into the left ventricle. The left ventricle is more muscular than the right ventricle because it must pump blood into the aorta to supply all the other arteries of the body.

When the heart muscle can no longer contract effectively, two specific changes in heart function occur:

The heart rate increases. The left ventricle enlarges in an effort to increase the amount of blood pumped each minute.

aortic valve

The one-way valve that lies between the left ventricle and the aorta and keeps blood from flowing back into the left ventricle after the left ventricle ejects its blood into the aorta; one of four heart valves.

Pain

The pain of an AMI differs from the pain of angina in three ways: It may or may not be caused by exertion, but it can occur at any time, sometimes when a person is sitting quietly or even sleeping. It does not resolve in a few minutes; rather, it can last between 30 minutes and several hours. It may or may not be relieved by rest or nitroglycerin. About one-third of patients never seek medical attention. It is not uncommon for the only complaint, especially in older patients and women, to be fatigue. AMI without the classic chest pain is often referred to as a silent MI. When you are called to a scene where the chief complaint is chest pain, complete a thorough assessment, no matter what the patient says. Patients with cardiac risk factors should be carefully assessed if they have any of the associated symptoms, even if no chest pain is present.

If an ALS service is not responding to the scene and your local protocols agree, you should begin transport when:

The patient regains a pulse. Six to nine shocks have been delivered (or as directed by local protocol). The machine gives three consecutive messages (separated by 2 minutes of CPR) that no shock is advised (or as directed by local protocol).

Secondary Assessment

The physical examination of a patient with chest pain begins with the cardiovascular system. Evaluate the patient's circulation by assessing pulses at various locations, and assess skin color, temperature, and condition. Is the skin cool or moist? How do the mucous membranes look? Are they pink, ashen, or cyanotic? Are the pulses of equal strength bilaterally? Does the patient have any edema in the extremities, especially the lower extremities? Examine the respiratory system for signs of inadequate ventilation. Are the lung sounds clear? Wet-sounding lungs indicate fluid is being moved into the lungs from the circulatory system. Are the breath sounds equal? Are the neck veins distended? Is the trachea deviated, or is it midline? Measure and record the patient's vital signs, including pulse, respirations, and blood pressure. Obtain readings for systolic and diastolic blood pressures. Take blood pressure on both arms if time allows. If available, use pulse oximetry. If you have access to continuous blood pressure monitoring, use it as well, making sure you get an accurate manual blood pressure first. Repeat the vital signs at appropriate intervals. Use the settings on the automatic blood pressure monitoring machine to remind you when it is time to recheck and record the vital signs. Note the time that each set of vital signs is taken. In patients with chest pain, it is valuable to have a 12-lead ECG tracing from as early as possible after the onset of the pain. EMTs may assist with placing electrodes.

Physical findings

The physical findings of AMI vary, depending on the extent and severity of heart muscle damage. The following are common: General appearance The patient often appears frightened. There may be nausea, vomiting, and a cold sweat. The skin is often pale or ashen gray because of poor cardiac output and the loss of perfusion. Occasionally, the skin will be cyanotic as the result of poor oxygenation. Pulse Pulse rate increases as a normal response to pain, stress, fear, or actual injury to the myocardium. You may feel an irregularity or even a slowing of the pulse. Pulse may also be dependent on the area of the heart that has been affected by the AMI. Damage to the inferior area of the heart often presents with bradycardia. Blood pressure Blood pressure may fall as a result of diminished cardiac output and diminished capability of the left ventricle to pump. Most patients with an AMI will have a normal or, possibly, elevated blood pressure. Respiration The respiratory rate is usually normal unless the patient has CHF. In that case, respirations may become rapid and labored with a higher likelihood of cyanosis and possibly frothy sputum. A complaint of difficulty breathing is common with cardiac compromise, so even if the rate seems normal, look at the work of breathing and treat the patient as if respiratory compromise were present. Mental status Patients with AMIs often experience confusion or agitation and sometimes experience an almost overwhelming feeling of impending doom. If a patient tells you, "I think I am going to die," pay attention. Consequences

Contraindications include:

The presence of a head injury Use of erectile dysfunction drugs within the previous 24 to 48 hours Drugs used for erectile dysfunction include sildenafil (Viagra), tadalafil (Cialis), avanafil (Stendra), and vardenafil (Levitra, Staxyn) The maximum prescribed dose of nitroglycerin has already been given (usually three doses)

Circulation (continued)

The right and left carotid arteries supply the head and brain with blood. The right and left subclavian arteries (under the clavicles) supply blood to the upper extremities. As the subclavian artery enters each arm, it becomes the brachial artery, the major vessel that supplies blood to each arm. Just below the elbow, the brachial artery divides into two major branches: the radial and ulnar arteries, supplying blood to the lower arms and hands. At the level of the umbilicus, the descending aorta divides into two main branches called the right and left iliac arteries, which supply blood to the groin, pelvis, and legs. As the iliac arteries enter the legs through the groin, they become the right and left femoral arteries. At the level of the knee, the femoral artery divides into the anterior and posterior tibial arteries and the peroneal artery, supplying blood to the lower legs and feet. Capillaries allow the exchange of nutrients and waste at the cellular level. The superior vena cava carries blood from the head and arms back to the right atrium. The inferior vena cava carries blood from the abdomen, kidneys, and legs back to the right atrium. The superior and inferior venae cavae join at the right atrium of the heart, where blood is eventually returned into the pulmonary circulation for oxygenation.

The autonomic nervous system has two parts:

The sympathetic nervous system Known as the "fight-or-flight" system Makes adjustments to the body to compensate for increased physical activity Speeds up the heart rate, increases respiratory rate and depth, dilates blood vessels in the muscles, and constricts blood vessels in the digestive system The parasympathetic nervous system Directly opposes the sympathetic nervous system Slows the heart and respiratory rates, constricts blood vessels in the muscles, and dilates blood vessels in the digestive system

Medical Direction

There should be a review of each incident in which the AED is used. After returning from the hospital or the scene, discuss with the rest of the team what happened to help everyone learn from the incident. Review such events by using the written report and the device's recordings, if applicable. There should also be a review of the incident by your service's medical director or quality improvement officer. Quality improvement involves the people using AEDs and the responsible EMS system managers. This review should focus on speed of defibrillation (the time from the call to the shock). Mandatory continuing education with skill competency review is generally required for EMS providers.

Guiding principles for cardiac monitoring are as follows:

To maintain the correct lead placement, it may be necessary to shave body hair from the electrode site. Be careful to avoid nicking the skin. If one is available, use an electric razor. To remove oils and dead tissues from the surface of the skin, rub the electrode site briskly with an alcohol swab before application. Wait for the alcohol to dry before applying electrodes or dry it with a quick wipe of a 4-inch × 4-inch gauze pad. This step may have to be repeated if the patient is very sweaty, as many cardiac patients are. Attach the electrodes to the ECG cables before placement. Confirm that the appropriate electrode attached to the cable is placed at the correct location on the patient's chest or limbs (each cable is marked and color coded as to the correct location for placement). Once all electrodes are in place, switch on the monitor and print a sample rhythm strip. If the strip shows any interference (artifact), verify that the electrodes are firmly applied to the skin and the monitor cable is plugged in correctly.

defibrillate

To shock a fibrillating (chaotically beating) heart with specialized electric current in an attempt to restore a normal, rhythmic beat.

angina pectoris

Transient (short-lived) chest discomfort caused by partial or temporary blockage of blood flow to the heart muscle; also called angina

Treatment

Treat a patient with CHF the same way as a patient with chest pain: Take vital signs and give oxygen by nonrebreathing mask with an oxygen flow of 10 to 15 L/min. Medical control may order the use of CPAP to move some of the fluid out of the lungs to provide better oxygenation. Allow the patient to remain sitting in an upright position with the legs down. Be reassuring; many patients with CHF are anxious because they feel as if they cannot breathe. Patients who have had problems with CHF before will usually have specific medications for its treatment. Gather these medications and take them along to the hospital. Nitroglycerin may be of value in reducing pulmonary edema if the patient's systolic blood pressure is more than 100 mm Hg. If the patient has been prescribed nitroglycerin, and medical control or standing orders advise you to do so, you can administer it sublingually. Prompt transport to the ED is essential.

Dissecting Anuerysm

Uncontrolled hypertension is the primary cause of dissecting aortic aneurysms. If the aorta ruptures, the amount of internal blood loss will be so large that the patient will die almost immediately. Signs and symptoms of a dissecting aortic aneurysm include very sudden chest pain located in the anterior part of the chest or in the back between the shoulder blades. The pain from an AMI is often preceded by other symptoms—nausea, indigestion, weakness, and sweating—and tends to come on gradually, getting more severe with time and often described as "pressure" rather than "stabbing." By contrast, the pain of a dissecting aortic aneurysm usually comes on full force from one minute to the next. A patient with a dissecting aortic aneurysm also may exhibit a difference in blood pressure between arms or diminished pulses in the lower extremities.

Left ventricular assist devices

Used to enhance the pumping of the left ventricle in patients with severe heart failure or in patients who need a temporary boost due to a myocardial infarction There are several types of LVADs. The most common ones have an internal pump unit and an external battery pack. These pumps may be pulsatile or they may be continuous, in which case the patient will not have any palpable pulses. If you encounter a patient with a LVAD, he or she (or his or her family members) may be able to tell you about the unit. Unless it malfunctions, you should not need to deal with it. If you are unsure of what to do, contact medical control for assistance. LVADs provide a number to call for assistance. Transport all LVAD supplies and battery packs to the hospital with the patient.

Reassessment

Vital signs should be reassessed at least every 5 minutes or any time significant changes in the patient's condition occur. If an AED is immediately available, use it; if not, perform CPR until the AED is available. Reassess your interventions to see whether they are helping and whether the patient's condition is improving. Reassessment will also determine whether further interventions are indicated or contraindicated. Early, prompt transport to the ED or specialty center is critical so that treatments such as clot-busting medications or angioplasty can be initiated. These treatments must be started as soon as possible after the onset of the attack. If the patient does not have prescribed nitroglycerin and you do not have permission from medical control to administer nitroglycerin, complete your patient assessment and prepare to transport. Do not delay transport to assist with administration of nitroglycerin. Document your assessment and treatment of the patient. Initiate all interventions according to protocol. If the intervention required an order from medical control, document the intervention and/or medication requested and that prior approval was granted. Record the patient's response to the intervention and the time of each intervention. On completing your documentation, obtain the medical control physician's signature (if required by local protocol) showing approval of medication administration.

If uncorrected, unstable ventricular tachycardia or ventricular fibrillation eventually lead to asystole.

Without CPR, asystole may occur within minutes. Asystole usually reflects a long period of ischemia, and nearly all patients you find in asystole will die.

Automaticity

allows a cardiac muscle cell to contract spontaneously without a stimulus from a nerve source.

Acute coronary syndrome (ACS)

describes a group of symptoms caused by myocardial ischemia. This can be a temporary situation known as angina pectoris, or a more serious AMI.

acute myocardial infarction (AMI),

f a blockage occurs in a coronary artery, the condition is known as an a classic heart attack.

hypertensive emergency

hypertensive emergency An emergency situation created by excessively high blood pressure, which can lead to serious complications such as stroke or aneurysm.

A thromboembolism

is a blood clot that floats through blood vessels until it reaches an area too narrow for it to pass, causing it to stop and block the blood flow at that point. Tissues downstream will become hypoxic. If too much time goes by before blood flow is resumed, hypoxic tissues die.

Atherosclerosis

is a disorder in which calcium and cholesterol build up and form a plaque inside the walls of blood vessels, obstructing flow and interfering with their ability to dilate or contract. Eventually, atherosclerosis can cause complete occlusion of a coronary artery. Atherosclerosis usually involves other arteries of the body as well.

An aortic aneurysm

is a weakness in the wall of the aorta.

Cardiac output

is calculated by multiplying the heart rate by the volume of blood ejected with each contraction (stroke volume). This is the volume of blood that passes through the heart in 1 minute. Is the best measure of the output of the heart

Ischemia

is decreased blood flow—in this case, to the heart.

Angina

is most often a symptom of atherosclerotic coronary artery disease. Occurs when the heart's need for oxygen exceeds its supply, usually during periods of physical or emotional stress when the heart is working hard. When the increased oxygen demand is gone, the pain typically goes away.

The autonomic nervous system

is the part of the brain that controls the functions of the body that do not require conscious thought, such as the heartbeat, respirations, dilation and constriction of blood vessels, and digestion of food.

stroke volume

is the volume of blood ejected with each ventricular contraction.

Infarction

means the death of tissue.

A dissecting aneurysm

occurs when the inner layers of the aorta become separated, allowing blood (at high pressures) to flow between the layers.

Bradycardia: Unusually

slow beating of the heart, 60 beats/min or less