abdominal thrusts: the procedure used to help clear an upper airway obstruction in a choking individual who is awake but unable to make sounds.
acid-base balance: the balance of acid and alkaline compounds. Measured on the pH scale, an increase in acids causes a decrease in pH; an increase in alkaline compounds causes an increase in pH. The lungs and kidneys are the primary organs that work to establish acid-base balance. See respiratory acidosis, metabolic acidosis, respiratory acidosis, and respiratory alkalosis.
acrocyanosis: bluish or purplish discoloration of the hands, feet, and distal parts of the face caused by disruptions in circulation. This condition is typically caused by decreased oxygenation to the tissues.
acute coronary syndrome (ACS): the group of disorders that can reduce coronary blood flow and ultimately lead to cardiac ischemia or infarction. Typically classified as either STEMI or NSTE-ACS.
acute life-threatening events recognition and treatment (ALERT) program: Program designed by a facility to ensure the early identification and treatment of pre-arrest patients and to identify a patient who is deteriorating even after interventions are performed. The program often includes involving the patient and family to alert staff of changes in the patient’s condition.
acute respiratory distress syndrome (ARDS): Fluid buildup in the alveoli causes the lungs not to receive enough air. In most cases, this is often caused by sepsis, inhalation of substances, and severe pneumonia. With decreased ventilation, less oxygen moves into the blood, and thus there is less available on the cellular level. The most common symptom is severe shortness of breath with rapid respiratory rate and hypotension.
adenosine: a medication used as a second-line treatment for supraventricular tachycardia when vagal maneuvers have not terminated the arrhythmia. Side effects include shortness of breath and hypotension. Adenosine is not useful for atrial fibrillation, atrial flutter, or ventricular tachycardia. Side effects may include chest pain, skin flushing, ventricular ectopy, and bradycardia.
adjunctive therapies: additional therapies used in ACLS that help to stabilize the patient with the goal of reducing long-term mortality.
afterload: the pressure the heart uses to eject blood during systole. This measurement is influenced by the aortic pressure of the left ventricle and pulmonary artery pressure of the right ventricle. The cardiac output decreases when cardiac afterload increases.
agonal gasps (agonal respirations): an abnormal respiratory pattern characterized by gasping or struggling to breathe due to reduced oxygen circulation in the blood.
airway obstruction: a partial or complete blockage of any of the breathing passages that lead to the lungs. Airway obstruction is usually classified as an upper or lower obstruction and is caused by mechanical or disease-specific causes.
algorithm: the set of sequential steps prescribed to treat a specific condition.
alternative airway: an adjunct that is often used to ensure that the patient is adequately ventilated. The alternative airways most commonly used include the endotracheal tube and laryngeal mask.
amiodarone: a medication used to control arrhythmias, including ventricular tachycardia, ventricular fibrillation, supraventricular tachycardia, wide complex tachycardia, and atrial fibrillation. Common side effects include hypotension, toxicity, visual changes, pneumonitis, and gastrointestinal symptoms.
analgesia: the loss of pain sensation from a deliberate disruption of the neural pathways between the sensory organ and the brain.
apnea: a temporary cessation of breathing that results in no movement of air into or out of the lungs
arrhythmia: a medical condition in which the heart beats in an abnormal rhythm.
arterial blood gas (ABG): the measurement of pH, pCO2, pO2, and HCO3 in an arterial blood sample. Normal values in the adult population are pH = 7.35–7.45; pCO2 = 35–45 mm Hg; pO2 = 80–100 mm Hg; and HCO3 = 22–26 mmol/L. (Lab values may differ slightly by institution.)
asystole: a Latin word for “without contractions,” also called cardiac standstill or flatline. The heart has stopped beating, and the patient has no cardiac output or heart muscle activity.
atrial fibrillation (AF): an abnormal heart rhythm caused by the irregular beating of the atria out of coordination with the ventricles.
atrial flutter (AFL): an abnormal rhythm used to describe a specific type of atrial tachycardia. This condition may often display as a second-degree heart block as the atrial rate becomes very rapid. This rhythm can be treated with medication, cardiac pacing, or cardioversion. In rare, recurrent cases, ablation therapy or surgical procedures might be necessary.
atrioventricular (AV) node: the part of the heart’s electrical system that coordinates conduction between the right atrium and right ventricle. The AV node is activated by impulses from the SA node.
atrioventricular (AV) block: an impairment of electrical impulses from the cardiac atria to the ventricles. This is typically caused by a block at the atrioventricular junction. AV block is further classified as first, second, or third degree.
atropine: a parasympathetic blocker and the drug of choice for treating symptomatic bradycardia. Atropine may be useful for AV block but not for Mobitz type II block, PEA, or asystole. The clinician should be prudent in cases of hypoxia and MI since atropine significantly increases oxygen demand.
automated external defibrillator (AED): a portable device that evaluates the heart rhythm and delivers an appropriate electrical shock to the heart when a shockable rhythm is detected.
automatic transport ventilator (ATV): a small, lightweight ventilator that can be used in out-of-hospital respiratory or cardiac arrest to support ventilation until the patient can be transported to the hospital. Depending on the model, an ATV may be capable of providing CPAP or BiPAP. Advantages over manual ventilation include control of rate and volume, a reduction in hyperventilation, the ability to titrate oxygen more closely to prevent hyper- or hypo-oxygenation, an audible warning of possible airway obstruction, and freeing up a rescuer to perform other tasks. Limitations include operator education on the machine, the need for oxygen to be in enough quantities, and the ability to “feel” lung compliance is not available.
autonomy: an ethical concept that preserves the patient’s right to make choices about their treatment, including the right to refuse treatment.
AVPU response scale: a system used to quickly evaluate an individual’s responsiveness. The mnemonic stands for: alert (fully awake and alert), voice (responds to voice commands), pain (responds only to pain), unresponsive (does not respond to voice or pain).
bag-mask ventilation: a handheld device that requires a rescuer to provide breaths to patients who have inadequate or absent breathing. Healthcare providers should be trained to use this essential part of the resuscitation standard equipment. The bag-mask can be used without additional oxygen, but if higher oxygen concentrations are required, supplemental oxygen is given.
barrier device: a device placed between the patient and rescuer that is used for rescue breathing. This device protects both individuals from the transfer of microorganisms.
basic life support (BLS): the most basic level of medical care that can be used by field personnel or trained bystanders to support the injured or ill patient until definitive treatment can be delivered at a hospital.
beneficence: the ethical concept that caregivers will do what is in the best interest of the patient.
biphasic defibrillator: a defibrillator that can be adjusted to increase or decrease the current and is more efficient at lower power than the older monophasic defibrillator. The biphasic defibrillator delivers a shock from two vectors. By delivering a lower power, there is less chance for damage to the heart muscle.
bradycardia: an abnormally slow heart rate for the individual’s age. In the adult population, the normal heart rate is 60–100 beats per minute but the heart rate normally varies with activity.
bradypnea: a lower than normal respiratory rate, typically < 12–18 breaths per minute for an adult.
C-A-B sequence: the current and preferred CPR sequence that teaches chest compressions, airway management, and breathing. The rationale for this order is that the individual cannot survive without circulation but can survive for a short time without additional oxygen entering the circulation.
calcium channel blockers: also called calcium antagonists since these medications block calcium from entering cells. They relax arterial walls and are often used to lower blood pressure.
calcium: the most abundant mineral in the body, calcium is required for cardiac contraction and vasodilation. Typically, calcium levels are held relatively constant in the body as the body can readily pull calcium from the bones.
capillary refill time: the time for color to return to a capillary bed after pressure is applied. Normal capillary refill time in the neonate is 3 seconds. In adults and older children, the normal time is < 2 seconds.
carbon dioxide detector (ETCO2): a device used to detect the amount of carbon dioxide in the systemic circulation.
carbon dioxide: Often represented as CO2, carbon dioxide is a byproduct of normal cellular respiration.
cardiac arrest: the sudden cessation of heart function.
cardiac markers: biomarkers (lab tests) that measure the function of the heart and are used to diagnose cardiac ischemia.
cardiac output: the volume of blood pumped by the ventricle each minute. Normally, this is calculated as heart rate x stroke volume.
cardiac tamponade: a serious but rare condition in which the heart is compressed due to fluid accumulation in the pericardial sac around the heart. The cause is usually chest trauma. Symptoms include hypotension, muffled heart tones, and jugular vein distension. These three symptoms make up the Beck triad.
carina: the point located on the trachea where the two mainstem bronchi branch out.
catecholamines: a type of neurohormone that is important in the body’s stress response and includes epinephrine or norepinephrine.
central cyanosis: bluish or purplish discoloration of the lips and mucous membranes. Although it can be caused by certain congenital deformities, it is most often the result of decreased oxygen in the blood.
chain of survival: According to the AHA ACLS standards, the chain of survival includes the steps that must be done to increase the chance for positive outcomes in a cardiac arrest situation. The steps include calling for trained emergency care, early and high-quality CPR, early application of shock therapy (defibrillation) as appropriate, and early ACLS as appropriate. Inability to perform any of these steps may result in increased morbidity and mortality in an arrest situation.
Cincinnati Prehospital Stroke Scale (CPSS): a simplified assessment that can be used by both laypersons and medical personnel to identify stroke. The person doing the assessment looks at the patient’s facial droop, arm drift, and clearness of speech. Abnormal findings on any of these parameters are suggestive of stroke, requiring immediate intervention.
closed-loop communication: a communication technique that involves the sender giving a message that is repeated back by the person receiving the message. If the repeated message is correct, the original sender responds with a “yes” message.
cold debriefing: discussion of the events after the resuscitation efforts have ceased. This is typically done in a face-to-face meeting after the team has had an opportunity to process the events of the resuscitation. The goal of a cold debriefing is to capture the effective and ineffective parts of the effort to ultimately improve care for all patients for continuous quality improvement.
compression fraction: the portion of CPR time during which compressions are being performed. To improve survival rates, the rescuer should strive for a compression fraction of 60–80%.
compression-only CPR: CPR performed without giving ventilatory breaths. Lay rescuers who are not trained in full CPR or who feel uncomfortable with the process are encouraged to learn compressions-only CPR to maintain enough circulation until definitive assistance arrives.
compression-ventilation ratio: the relationship between the number of chest compressions and breaths given during cardiopulmonary resuscitation. For single-rescuer situations, the ratio is 30 compressions to 2 ventilations for all ages. When two rescuers are available, the compression-ventilation ratio remains at 30 to 2 for adults but changes to 15 compressions to 2 ventilations for the pediatric population.
congestive heart failure (CHF): a heart condition often caused by coronary artery disease that leads to damage of the heart muscle. It is characterized by severe shortness of breath, irregular heartbeat, and fatigue.
contiguous leads: On a 12-lead ECG, this refers to the leads that look at the same anatomical area of the heart and are used to describe areas of heart muscle damage. The term is also used to describe precordial leads that are next to each other. Inferior leads are II, III, and aVF; lateral leads are I, aVL, V5, and V6; septal leads are V1 and V2; anterior leads are V3 and V4.
continuous positive airway pressure (CPAP): a form of ventilation that applies continuous air pressure throughout the respiratory cycle to keep airways open. Typically used in individuals who can breathe on their own.
continuous quality improvement (CQI): The focus of CQI is to improve outcomes by improving the education of the community, CPR quality, rapid response systems, and post-cardiac arrest care. In this process, the team sets goals, develops processes to meet the goals, measures progress, and holds individuals accountable.
coronary angiography: a specialized X-ray used in cardiac catheterization in which a radioactive agent is injected into the coronary vessels to highlight and visualize any occlusion of the coronary arteries.
coronary arteries: the blood vessels that supply blood to the myocardium. The two large coronary arteries are the left main and the right coronary arteries. The left main further divides into the left anterior descending artery that supplies blood to the left ventricle and atrium and the circumflex artery that circles the heart and supplies blood to the outside and back of the heart.
coronary atherosclerosis: the narrowing of a cardiac artery usually due to buildup of plaque in the arterial walls.
coronary thrombosis: formation of a blood clot in one of the vessels of the heart.
cricoid pressure: No longer routinely recommended in ACLS, this maneuver describes the application of pressure on the cricoid cartilage of the neck to occlude the esophagus and make the glottis more visible.
cricothyrotomy: an emergency procedure to open the airway when a patent airway cannot be established by positioning or placement of an advanced airway. Typically, cricothyrotomy is only performed when the airway is obstructed or when a facial injury prevents the establishment of an airway.
cyanosis: a bluish or purplish discoloration of the skin due to decreased oxygen in the blood. See acrocyanosis and central cyanosis.
defibrillation: the definitive treatment for ventricular tachycardia or ventricular fibrillation that consists of delivering an unsynchronized shock to the cardiac muscle using a defibrillator.
depolarization: In the normal heart, the SA node begins the electrical activity by sending a signal through the atria, causing those chambers to contract (P wave on the ECG). When the impulse reaches the AV node, the ventricles contract (QRS).
DNR: refers to a do not resuscitate order that reflects a patient’s instruction not to provide CPR in the case of cardiorespiratory arrest.
dopamine: a vasopressor commonly indicated for the treatment of cardiogenic or distributive shock. Dopamine will increase the patient’s systemic vascular resistance, heart rate, and myocardial contractility.
DOPE: a mnemonic used to remind the team of possible causes of respiratory deterioration after intubation, with the letters representing: displaced ET tube, obstructed ET tube, pneumothorax, and equipment failure.
early warning sign symptoms (EWSS): a system defined by the facility that includes signs and symptoms that should result in specific interventions by the care team. These include respiratory rate, oxygen saturation decrease, the need for supplemental oxygen, elevated or decreased temperature, low or high systolic blood pressure, increased or decreased heart rate, and altered level of consciousness.
E-C technique: a one-handed technique for positioning and holding a face mask on the patient during ventilation. In this technique, the thumb and index finger form a C over the top and bottom of the mask, and the other three fingers form an E by holding the mandible. Unless the rescuer has large hands, this technique is less effective in adults than in children.
echocardiogram: a noninvasive ultrasound test that evaluates the blood flow, heart muscle, chambers, and valves.
edema: an abnormal collection of fluid in the soft tissues resulting in swelling.
ejection fraction (EF): measurement of the amount of blood being pumped by the heart with each contraction. EF is typically expressed as a percentage, with normal between 55 and 70%. Lower EF measurements are usually indicative of heart failure.
electrocardiogram (ECG): a noninvasive recording of the electrical activity of the heart. Electrodes are placed in specific locations on the individual’s skin to record activity in all areas of the heart.
end-tidal carbon dioxide (ETCO2): a noninvasive measurement of exhaled carbon dioxide through a capnograph used to determine the adequacy of CPR. If the measurement is < 10 mm Hg, blood flow to the lungs is decreased, and the team should assume that compressions or airway management are not optimal.
endotracheal intubation: also called tracheal intubation, the placement of a plastic tube into the trachea to keep the individual’s airway open and provide ventilation during resuscitation.
endotracheal tube (ET tube): a plastic tube that is used in the endotracheal intubation procedure to keep the airway patent.
epiglottis: an elastic cartilage shaped like a flap that overlies the glottis.
epinephrine: a naturally occurring hormone that aids in regulating the sympathetic autonomic nervous system. As a powerful vasopressor, epinephrine (or adrenaline) increases blood pressure, heart rate, and cardiac output. In resuscitation, epinephrine is used as a cardiac stimulant to treat persistent bradycardia, cardiac arrest rhythms, anaphylaxis, and hypotension.
exclusion criteria: findings that would indicate a patient is not a good candidate for a particular study or treatment. May be absolute (should never be done) or relative (the clinician should use clinical judgment when making the treatment decision).
extracorporeal cardiopulmonary resuscitation: Known by different names, ECLS and ECMO, this is a type of mechanical circulatory support for patients with cardiogenic shock that is unresponsive to medical treatment. These technologies provide temporary support for cardiac output and oxygenation until definitive treatment is established.
fibrinolytic checklist: the steps the team should go through to determine a patient’s suitability for fibrinolytic treatment.
fibrinolytic therapy: the use of fibrinolytic agents such as alteplase to dissolve clots in coronary/cerebral vessels.
fibrinolytics: medications used to dissolve clots by attacking the fibrin in the clot.
FiO2: the fraction of inspired oxygen is the concentration of oxygen in a mixture of gas administered to the patient.
first-degree AV block: a cardiac arrhythmia caused by an obstruction in the heart’s conduction system at the AV node. The impulse through the AV node is slowed, causing a prolonged PR interval on the ECG.
foreign-body airway obstruction (FBAO): an obstruction of the upper airway due to aspiration of food or small objects.
functional residual capacity (FRC): refers to the amount of air left in the lungs at the end of passive expiration. During passive expiration, the lungs and chest wall are in equilibrium, and there is no pressure on the respiratory muscles. The remaining air makes it easier to fill the lungs with the next inspiration. If inhalation and exhalation are not in balance, the patient will have a decreased ability to absorb oxygen or remove carbon dioxide.
gasping: abnormal respiratory effort in which the individual attempts to inhale or exhale with quick, ineffective breaths. The clinician should immediately intervene to provide effective ventilation.
Glasgow coma scale (GCS): method for evaluating the patient’s level of consciousness to determine the severity of head injury using eye-opening, best verbal response, and best motor response. Mild = 13–15; moderate = 9–12; severe = 3–8.
glottis: an opening of the larynx, the passageway into the trachea.
glucose level: the amount of glucose (sugar) in the blood. Normal blood glucose in the adult is 80–120 mg/dL.
Global Registry of Acute Coronary Events (GRACE): a risk calculator used to assess the likelihood of death for patients with ACS. It was originally an international registry that compiled data from over 100,000 patients. The calculator was built from the gathered data.
Hs and Ts: the most common causes of cardiac arrest, including hypovolemia, hypoxia, hydrogen ion excess, hypo-/hyperkalemia, hypothermia, tension pneumothorax, tamponade, toxins, and thrombosis (pulmonary or coronary). Detection and correction of these disorders can help resolve the cardiac arrest situation by treating the underlying cause.
head-tilt chin-lift maneuver: a technique for opening the airway in which the patient’s head is tilted and the chin is lifted, so the head is in the “sniffing” position. This technique should NOT be used in a suspected cervical spine injury. Instead, the team should use the jaw-thrust maneuver.
hemorrhagic stroke: brain infarction caused by rupture of a blood vessel with bleeding into the brain.
heparin: a medication used for its anticoagulant effects.
high-quality cardiopulmonary resuscitation: High-quality CPR refers to the current American Heart Association (AHA) recommendations for a compression rate of 100–120 per minute for all ages and a compression depth of at least 2 inches for adults and a depth of at least 1/3 of the anterior-posterior diameter of the chest for infants and children (usually 1.5–2 inches).
hot debriefing: a meeting immediately following resuscitation efforts when the team has the best memory of events that occurred during the resuscitation. The goal of a hot debriefing is to capture the actions that were effective and ineffective to ultimately improve care for all patients for continuous quality improvement.
hypercapnia: abnormally high carbon dioxide level in the blood caused by the retention of carbon dioxide. The body’s normal compensatory mechanism for this condition is to increase the respiratory rate.
hyperglycemia: an abnormally high level of glucose in the blood. Normal glucose in the adult is 80–120 mg/dL of blood before meals.
hyperkalemia: a higher than normal potassium level. The normal potassium level is between 3.5 and 5.5 mmol/L. Hyperkalemia is a normal variation in extremely premature infants, but variations in the adult population are associated with increased morbidity and mortality.
hypertension: a blood pressure higher than normal expected range. In 2017, the American Heart Association and American College of Cardiology redefined the guidelines for blood pressure. In the new guidelines, the following categories apply:
Category | Definition |
Normal | < 120/80 mm Hg |
Elevated | systolic BP 130–139 and diastolic BP < 80 mm Hg |
Stage 1 | systolic BP 130–139 or diastolic BP 80–89 mm Hg |
Stage 2 | systolic > 139 or diastolic at least 90 mm Hg |
Hypertensive crisis | systolic > 180 or diastolic > 120 mm Hg |
hyperthermia: a higher than normal body temperature. Normal adult temperature is 97.0–99.0 degrees Fahrenheit (36.1–37.2 degrees Celsius).
hypocapnia: lower than normal carbon dioxide levels in the blood resulting in respiratory alkalosis. Usually caused by hyperventilation, it can lead to tetany, dizziness, and confusion.
hypoglycemia: a lower than normal blood glucose level. Normal glucose in the adult is 80–120 mg/dL of blood before meals.
hypokalemia: a lower than normal potassium level. Normal potassium level is between 3.5 and 5.5 mg/dL.
hypotension: a lower than normal blood pressure.
hypothermia: a lower than normal body temperature. Normal adult temperature is 97.0–99.0 degrees Fahrenheit (36.1–37.2 degrees Celsius).
hypovolemia: a lower than normal circulating intravascular volume. Normal adult blood volume is approximately 9% of total body weight. In the average adult, this is approximately 3.5–5.0 liters.
hypovolemic shock: significant blood or body fluid loss resulting in a sudden drop in blood volume that can lead to an inability of the heart to pump enough oxygen to the vital organs. As fluids decrease in the body, the heart must work harder and beat faster to maintain adequate blood pressure and cardiac output.
hypoxemia: an abnormally low level of oxygen in arterial blood, most often caused by respiratory disorders or obstruction.
hypoxia: an inadequate oxygen supply at the tissue level to meet the body’s metabolic demands. Causes of hypoxia can include pulmonary disease, congenital heart disease, airway obstruction, or sepsis. Hypoxia will often lead to hyperventilation.
in-hospital cardiac arrest: a cardiac arrest that occurs within the confines of an acute care hospital. Improved outcomes are associated with in-hospital arrest, but, more importantly, with post-arrest care that occurs in the hospital setting.
inspiratory time: the duration of inhalation. In a ventilated individual, it is the amount of time to deliver the tidal volume of O2 to the lung.
intraosseous (IO) access: circulatory access through the bone marrow when the umbilical vein or other IV access is not readily available. In the case of cardiac arrest, IO access is a quick and easy way to establish circulatory access. This method is contraindicated if there is a long-bone fracture in the extremity.
intravenous (IV) access: circulatory access through a vein. During CPR, this is the route of choice if a site can be obtained without interrupting compressions.
invasive arterial blood pressure: monitoring that measures the arterial blood pressure by inserting an arterial line into an accessible artery.
ischemic changes: changes on the ECG tracing (usually in the ST segment and T wave) indicating that myocardial damage (ischemia) has occurred. This usually involves ST deviation from the isoelectric line and changes in the T wave.
ischemic stroke: brain infarction caused by occlusion of a blood vessel that supplies the brain, resulting in decreased oxygen to the cells and cellular death.
jaw-thrust maneuver: a technique for opening a patient’s airway when a cervical spine injury is possible. The rescuer pushes the lower jaw forward while maintaining the neck in a neutral position.
lactic acidosis: a type of metabolic acidosis with decreased blood pH below normal. This can be caused by hypoglycemia, hypoxia, seizures, kidney disease, sepsis, certain poisonings, and prolonged dehydration.
laryngeal mask: a supraglottal advanced airway that keeps the individual’s airway open. Easier to insert than an endotracheal tube, the laryngeal mask helps to ensure an airtight seal on top of the glottis.
laryngoscope: a type of endoscope used to visualize the larynx. The laryngoscope is typically a rigid instrument equipped with a light that illuminates the vocal cords.
larynx: an anatomical segment that connects the pharynx and the trachea.
lidocaine: An antiarrhythmic medication indicated for ventricular fibrillation, pulseless ventricular tachycardia, wide-complex tachycardia with pulses, and used in rapid sequence intubation. Lidocaine decreases the automaticity of the cardiac fibers and decreases intracranial pressure.
lower airway obstruction: an obstruction of the bronchi and bronchioles in the chest cavity.
magnesium sulfate: a bronchodilator and electrolyte replacement indicated for refractory asthma, torsades de pointes, and low magnesium levels, relaxes smooth muscle and acts as an antiarrhythmic. It is not recommended for use in cardiac arrest due to VF or pulseless VT.
mainstem bronchi: the major air passageways leading to the right and left lungs.
manual defibrillator: a defibrillator that requires medical decision-making and rhythm analysis by the responder to deliver a shock.
mechanical capture: When noninvasive transcutaneous pacing is implemented, mechanical capture is the contraction of the heart that results in a pulse and increased cardiac output.
metabolic acidosis: When the kidneys cannot remove acids, body fluids become acidic. Metabolic acidosis can be caused by hypoglycemia, diabetic ketoacidosis, hypoxia, seizures, kidney disease, certain poisonings, sepsis, diarrhea, and prolonged dehydration.
metabolic alkalosis: When the blood has high levels of bicarbonate, and the kidneys cannot excrete the excess, the blood pH increases. This is typically due to decreased oxygenation, fever, lung disease, and high altitude. Symptoms include muscle spasms and tremor, nausea and vomiting, tingling, and confusion.
monomorphic ventricular tachycardia: ventricular tachycardia in which the heart beats originate from the same source and the QRS complexes appear similar on the ECG.
monophasic defibrillator: the older style of defibrillator that has been replaced by the biphasic in most EDs. These defibrillators deliver a shock in a single direction from one chest electrode to the other. Higher energy levels must be used with a monophasic defibrillator, which can result in heart damage.
myocardial oxygen demand: the amount of oxygen the heart needs to function optimally. The demand is related to the level of activity of the heart.
myocarditis: inflammation of the heart muscle, or myocardium. A viral infection is the most common cause of myocarditis.
myocardium: the heart muscle, which is the thick, middle layer of the heart wall that contains primarily contractile muscle cells.
naloxone: Also called Narcan, this medication can be given to reverse respiratory depression caused by opioid overdose. Most emergency responders (police, fire, and EMS) now carry naloxone. It may also be given by a lay rescuer who has been trained to respond to patients with opioid overdose.
nasopharyngeal airway (NPA): an airway adjunct used in the management of less severe cases of airway obstruction. The NPA is inserted through the nose and to the base of the tongue to prevent the tongue from covering the epiglottis.
nasopharynx: the upper part of the throat behind the nose and above the soft palate.
National Institutes of Health Stroke Scale (NIHSS): a tool used to quantify the level of impairment caused by a stroke at a point in time.
NAVEL (meds for ET tube): a mnemonic for the medications that can be safely administered via an ET tube. They are naloxone, atropine, vasopressin, epinephrine, and lidocaine.
nitrates: vasodilators that increase the diameter of blood vessels, causing decreased work of the heart and decreased blood pressure.
nitroglycerin: a nitrate medication used to decrease pain and blood pressure in AMI.
nonshockable rhythms: cardiac arrhythmias that will NOT respond to cardioversion or defibrillation, namely, PEA and asystole. They are considered nonshockable since they do not have an electrically identifiable spike.
non-ST elevation-acute coronary syndrome (NSTE-ACS): acute coronary syndrome not associated with ST elevation on ECG.
non-ST segment myocardial infarction (NSTEMI): one of the forms of acute coronary syndrome. NSTEMI symptoms include those associated with unstable angina. NSTEMI is differentiated from STEMI by analysis of the ST segment on the ECG. For NSTEMI, the ST segment is normal. Typically, heart muscle damage due to this type of MI is less than for STEMI.
norepinephrine: a vasopressor indicated for the treatment of hypotensive shock that is not responsive to fluid resuscitation
normal sinus rhythm (NSR): the cardiac rhythm that results when the electrical impulse originates in the sinus node and travels through the normal conduction pathway to produce the characteristic rhythm of a healthy heart at rest.
normothermia: a normal body temperature.
opioid toxicity: an overdose due to excessive opioids, resulting in decreased respirations and loss of consciousness.
oropharyngeal airway: an airway adjunct used to maintain an open airway by preventing the tongue from falling back over the epiglottis and causing airway obstruction.
orthostatic intolerance: low blood pressure and dizziness when standing. The symptoms usually subside when the individual lies down.
out-of-hospital cardiac arrest (OHCA): a cardiac arrest that occurs in any location other than an acute care hospital. Differences in the availability of trained personnel and treatment modalities make the survival of an OHCA more unlikely than survival from an IHCA.
oxygen blender: a device that mixes oxygen with compressed air. This device allows the clinician to deliver less than 100% oxygen but a concentration greater than room air (21%) oxygen.
oxygen saturation: the percentage of oxygen-rich hemoglobin relative to the total hemoglobin. Normal for a child and adult will be > 94% when breathing room air.
oxygen: the chemical element that is often specified as O2. Room air contains approximately 21% oxygen at sea level.
paroxysmal supraventricular tachycardia (PSVT): a type of supraventricular tachycardia that usually begins and ends abruptly and may cause shortness of breath, palpitations, and lightheadedness.
peak expiratory flow rate (PEFR): measures the patient’s maximum speed of expiration. PEFR is measured using a peak flow meter. This measurement is most reliable in adolescents and adults who understand the measurement process and is less useful in young children. The normal PEFR is based on gender, age, and height.
peak inspiratory pressure (PIP): the highest pressure in the lungs during the inspiratory phase.
percutaneous coronary intervention (PCI): along with fibrinolytics, one of the most used interventions to treat STEMI. In this procedure, stents are placed in the occluded cardiac vessel(s) to mechanically hold the vessel(s) open. As compared with fibrinolytic therapy, studies show that PCI has better long-term results for keeping vessels open with less risk of stroke and death.
perfusion pressure: the difference between the diastolic pressure in the aorta and the left ventricular end-diastolic pressure.
pericardiocentesis: the treatment for cardiac tamponade involving aspiration of fluid from around the heart.
peripheral cyanosis: blue or purple discoloration of the hands and feet. Normal in the neonate, this is a sign of decreased oxygenation in the older individual.
permissive hypoxemia: the concept of allowing lower than normal oxygen levels in arterial blood to prevent the risks of high oxygen therapy.
pneumothorax: a condition in which a lung is partially or completely collapsed. A common cause of pneumothorax is trauma to the chest and over-inflation of the lungs from aggressive ventilation that causes the alveoli to rupture.
polymorphic ventricular tachycardia: ventricular tachycardia in which the heart beats originate from different sources, causing the QRS complexes to appear different on the ECG.
positive end-expiratory pressure (PEEP): a form of ventilation that applies air pressure in the respiratory cycle at the end of exhalation to keep airways from collapsing during rest.
Positive pressure ventilation (PPV): a technique of artificial respiration using a mechanical ventilator to force air into the lungs of the patient. PPV is used when spontaneous breathing is either inadequate or absent. PPV is accomplished by volume-cycled ventilators (those that terminate the inspiration at a preset volume), pressure-cycled ventilators (those that terminate the inspiration at a preset pressure), or time-cycled ventilators (those that terminate the inspiration at a preset time).
post-cardiac arrest care: care measures used to reduce morbidity and mortality after successful resuscitation. Most important during the period following ROSC is maintaining adequate blood pressure, running serial ECGs, therapeutic hypothermia, and monitoring oxygenation using waveform capnography as indicated.
precordial thump: a procedure that can be used in VF or pVT in a witnessed arrest when a defibrillator is not available. The caregiver strikes the patient in the middle of the sternum with a closed fist.
preload: the end-diastolic volume of the ventricles just prior to contraction of the ventricles.
primary assessment: includes an assessment of airway-breathing-circulation-disability-exposure approach (ABCDE) to evaluate the respiratory function, cardiac function, and neurologic function of the patient. The primary assessment also includes taking the patient’s vital signs.
priority-based multiple-rescuer response: the protocol that designates which member of the team performs which functions and in what order. A resuscitation often begins with one rescuer, and other team members join the team as they are available. Facility protocol will designate what the essential duties are and who will accomplish each task in the context of the team.
procainamide: an antiarrhythmic that works as a sodium channel blocker.
public safety answering points (PSAP): a community-based protocol that trains EMS dispatchers to do just-in-time training to members of the public who might discover a patient in cardiac arrest.
pulmonary edema: an accumulation of fluid in the air spaces of the lungs that results in impaired air exchange and eventually respiratory failure.
pulmonary embolism (PE): a mechanical blockage of a blood vessel in the lungs leading to chest pain, cough, and shortness of breath. A PE can result in obstructive shock leading to low cardiac output, decreased tissue perfusion, and an increase in systemic vascular resistance to compensate for the other issues.
pulse oximetry: use of a device that measures the oxygen saturation through the skin. Pulse oximetry should always be available and utilized when resuscitation is anticipated or when supplementary oxygen or PPV is administered.
pulseless electrical activity (PEA): a common arrhythmia during resuscitation in which the cardiac monitor shows electrical activity without palpable pulses. In this situation, defibrillation is not the treatment of choice. Instead, the team must continue CPR and use the Hs and Ts to quickly identify the cause of the arrest. The most common cause of PEA is hypoxemia.
pulseless ventricular tachycardia (pVT): a life-threatening cardiac arrhythmia characterized by a heart rate > 180 beats/minute, wide QRS complex, and lack of a palpable pulse. The rhythm originates in the ventricles rather than the atrial node.
quantitative waveform capnography: noninvasive and continuous measurement of end-tidal carbon dioxide. This is the best way to verify ventilation in the intubated patient during cardiopulmonary resuscitation. It is the most reliable method for detecting the return of spontaneous circulation.
rapid response team (RRT): a trained team that proactively predicts and intervenes when a patient in the hospital is deteriorating. The RRT can intervene quickly and forestall a full deterioration that might result in full cardiopulmonary arrest.
recombinant tissue plasminogen activator (rtPA): a laboratory-produced tissue plasminogen activator used to treat ischemic stroke.
recovery position: following the return of effective circulation and breathing, the rescuer should roll the patient onto the side, placing their head in a dependent position. This position will help to maintain a patent airway by decreasing pressure on the patient’s lungs and allowing emesis to flow out from the mouth.
refractory: the time after a contraction of the heart muscle during which it is recovering and cannot contract.
reperfusion therapy: any treatment that restores blood flow. This may include removal of a blockage or dissolving a clot in an occluded artery.
repolarization: the successive relaxation of the atria and ventricles following the contraction of the chambers in a normal heart represented by a T wave on the ECG.
respiratory acidosis: When the lungs cannot remove carbon dioxide, body fluids become acidic, resulting in respiratory acidosis. This disorder is most often caused by chest injuries, airway disease, or chronic lung disease. Symptoms include shortness of breath and confusion.
respiratory alkalosis: a state of increased pH when the blood has low levels of carbon dioxide. This is typically due to decreased oxygenation, fever, lung disease, and high altitude. Symptoms include muscle spasms and tremor, nausea and vomiting, tingling, and confusion.
respiratory arrest: absent or extremely inadequate oxygenation and ventilation. This condition assumes that the patient has a palpable pulse and circulation.
respiratory distress: when a patient has trouble breathing and exhibits signs such as increased respiratory rate, retractions, accessory muscle use. This can be caused by lung disease, infection, or obstruction.
respiratory failure: a late stage of respiratory distress in which the gas exchange between the air and the blood cannot match the metabolic demands of the body. Signs and symptoms of respiratory failure include those of respiratory distress, such as tachypnea, tachycardia, hypertension, stridor, diminished breath sounds, paradoxical chest wall movement, and use of accessory muscles during respiration. However, impending respiratory failure is heralded by a slowed respiratory rate as the patient tires, bradycardia, and a decreasing level of consciousness.
return of spontaneous circulation (ROSC): the return of cardiac circulation and respiratory effort after a cardiac arrest event. Signs of ROSC include palpable pulses, spontaneous movement, visible respiratory effort, and a blood pressure that can be measured.
SAMPLE: a mnemonic used during resuscitation to remind the team of further questions to consider before, during, and after resuscitation. The mnemonic stands for signs/symptoms, allergies, medications, past medical history, last meal, and events leading up to the precipitating event.
secondary assessment: a patient assessment that includes a history of the present illness and a focused physical assessment based on the patient’s current condition.
second-degree AV block (types 1 and 2): a cardiac arrhythmia caused by an obstruction in the heart’s conduction system at the AV node. In type 1, the impulse through the AV node is progressively increased, resulting in increasingly long PR intervals until a QRS is completely missing on the ECG. In type 2, there is more than one P wave for every conducted QRS complex.
self-inflating bag: one of the two types of manual ventilation bag; the self-inflating bag refills itself when the responder stops squeezing the bag. Also, see a flow-inflating bag.
shock: a life-threatening medical condition characterized by rapid breathing, cool skin, rapid and weak pulse, dizziness, faintness, and decreased blood pressure. Shock is categorized as compensated or decompensated and typed as anaphylactic, cardiogenic, distributive, hemorrhagic, hypovolemic, and septic.
shockable rhythms: an arrhythmia that can be interrupted by electrical shock. The two shockable rhythms are VF and pulseless VT.
sinoatrial (SA) node: Sometimes called the heart’s pacemaker, the SA node is the small group of cells in the right atrium that produces an electrical impulse through the heart, causing it to contract.
sinus tachycardia: a rhythm that originates in the atria but has a faster than expected heart rate for the individual’s age.
sodium bicarbonate: an electrolyte that acts as an alkalinizing agent. Less commonly used in resuscitation than in the past, sodium bicarbonate continues to be indicated for very severe metabolic acidosis, certain poisonings, and hyperkalemia.
sotalol: an antiarrhythmic used as another option for the treatment of arrhythmias.
stable tachycardia: an abnormally high heart rate in a patient without signs of decompensation. In the adult population, the normal heart rate is 60–100 beats/minute, and the heart rate normally varies with activity. A faster than normal heart rate can be caused by infection, illness, fever, and medications. Stable tachycardia is characterized by no significant signs or symptoms of hemodynamic instability, e.g., hypotension or altered mental status. The team must support the patient while attempting to identify the underlying cause of the tachycardia.
ST elevation myocardial infarction (STEMI): a heart attack characterized by cardiac muscle damage due to a decreased blood supply to a part of the heart. This MI is seen as ST segment elevation on the ECG.
stridor: an abnormal breath sound seen during inspiration that is usually described as high-pitched or crowing. It is associated with upper airway obstruction.
stroke volume: the volume of blood pumped out from the left ventricle with each contraction.
stroke: Typically classified as hemorrhagic (bleeding into the brain) or ischemic (blocked artery), a stroke is often referred to as a “brain attack” since blood flow to a part of the brain is diminished or absent causing oxygen deprivation to that area. Symptoms may include weakness or paralysis, difficulty speaking or understanding speech, and confusion.
suction equipment: equipment used to clear the airway of secretions.
supraglottic airway devices: adjunct airway devices such as an LMA, and I-gel that are used to manage the patient’s airway during resuscitation.
supraventricular tachycardia (SVT): a fast heart rhythm that originates above the ventricles. Signs and symptoms of SVT include chest pain, diaphoresis, shortness of breath, and dizziness.
synchronized cardioversion: an energy shock that is timed to be delivered at a particular point in the cardiac rhythm to avoid the relative refractory period. The purpose is to restore normal cardiac activity and to convert atrial fibrillation, atrial flutter, atrial tachycardia, and supraventricular tachycardia when medications have not been successful.
systems of care: The AHA guidelines stress the importance of the development of total systems of care with training for all levels from community members, emergency response systems, physicians, and hospitals.
tachypnea: an abnormally high respiratory rate, typically > 12–18 breaths per minute for an adult. Tachypnea is a sign of impending respiratory failure in all age groups, so it should be monitored and treated.
therapeutic hypothermia: lowering the core temperature using cooling devices after cardiac arrest to shunt blood from the periphery to the vital organs (brain, heart, and lungs). The temperature is usually lowered to 32–36°C and maintained for at least 24 hours.
third-degree AV block: a cardiac arrhythmia caused by an obstruction in the heart’s conduction system that causes an impulse not to move into the ventricle. At this point, an accessory pacemaker in the ventricle begins to generate the QRS complexes. On the ECG, the P waves will usually be regular but not associated with the QRS complexes.
thoracentesis: a procedure in which a catheter is inserted into the pleural space as a method of removing air or fluid from inside the thoracic cavity.
thyroid cartilage: a thick cartilage surrounding the larynx to protect it.
Thrombolysis in Myocardial Infarction Score (TIMI): a scoring tool used to determine the probability of mortality or ischemic events in patients with non-ST-segment elevation myocardial infarction or unstable angina.
torsades de pointes: an arrhythmia often described as a form of polymorphic ventricular tachycardia. The danger of this arrhythmia is that it can degenerate into VT or VF and result in sudden cardiac death.
toxins: poisons that may be produced by the body or introduced from an external source and cause detrimental effects on the body’s metabolic processes.
trachea: the segment of airway between the larynx and the carina.
transthoracic pacing: the regulation of the heart rate by an artificial pacemaker with electrodes that are attached to the external chest wall.
troponin: one of the biomarkers that measure proteins released when the cardiac muscle is damaged. An elevated troponin may be an indicator of AMI.
unstable tachycardia: an abnormally high heart rate characterized by a lower than normal cardiac output that causes serious signs and symptoms of hemodynamic instability.
upper airway obstruction: a blockage of the trachea, larynx, or throat that impairs air movement into the lungs.
vagal maneuvers: maneuvers to stimulate the vagus nerve. This technique helps to slow supraventricular tachycardic rhythms. Bearing down as if having a bowel movement, carotid massage, and immersing the face in ice water are common vagal maneuvers that may slow rapid rhythms.
Valsalva maneuver: a maneuver to stimulate the vagus nerve in which the patient exhales forcefully against a closed nose and mouth. This technique may be successful in slowing a tachycardic cardiac rhythm.
vascular resistance: the resistance of blood flow through vessels in the circulatory system. When in the peripheral circulation, this resistance is known as systemic vascular resistance (SVR). In the lungs, it is termed pulmonary vascular resistance (PVR).
vasopressin: No longer an AHA recommended medication, this drug was used as an alternative to epinephrine for refractory VF not relieved by shock. It may also be used for asystole, PEA, and septic shock. The clinician should be aware of the potential for angina, so it should be avoided in patients with coronary artery disease.
ventilation-perfusion mismatch: Ventilation-perfusion is the ratio that reflects the adequacy of the respiratory process. A mismatch is an indication that either the lungs are receiving oxygen with no blood flow or blood flow with no oxygen.
ventricular fibrillation (VF): a cardiac arrhythmia characterized by fibrillation of the ventricles instead of effective contractions.
verapamil: a calcium channel blocker used to treat hypertension, anginal chest pain, and supraventricular tachycardia.
vocal cords: two membranous tissues at opposite locations that project medially from the walls of the larynx and form a slit across the glottis. The edges of the vocal folds vibrate when an airstream passes through them, causing modulation to produce the voice.
wide complex tachycardia: a special type of tachycardia in which the QRS complex is > 0.12 seconds
Wolff-Parkinson-White (WPW) syndrome: a syndrome in which an extra electrical pathway in the heart leads to episodes of supraventricular tachycardia. The ECG will show a shortened PR interval and a characteristic delta wave with a tachycardic heart rate.
work of breathing: the energy required to inhale and exhale. The calculation is typically measured as Joules/Liter or Joules/minute. In a normal resting individual, approximately 3% of the total energy is consumed during the process of breathing. The calculation is the work of breathing = Pressure x Volume. If either of these factors increases, the work of breathing also increases.