EMT Ch. 17- Cardiovascular Emergencies

sinoatrial (SA) node

• located in upper part of RA

• normal electrical impulses begin

• travels across both atria stimulating them to contract

atrioventricular (AV) node

• located between atria & ventricles

• bridge of electrical tissue impulses cross

• signal slowed for 1-2/10 of second to allow blood to pass from atria to ventricles

automaticity

allows cardiac muscle cell to contract spontaneously w/o stimulus from nerve source

bright red blood cells

oxygenated blood cells

dark red blood cells

deoxygenated blood cellsl

white blood cells

fight infection

platelets

coagulants; smaller than white/red blood cells

plasma

fluid in which cells float; mixture of water, salts, nutrients, proteins

systolic blood pressure

maximum pressure exerted against artery walls during contraction of left ventricle

diastolic blood pressure

maximum pressure exerted against artery walls during relaxation of left ventricle

cardiac cycle consists of:

one systolic & one diastolic time period

cardiac output equation

HRxSV

components of good perfusion

1. well-functioning heart (operate at appropriate rate)

2. adequate volume of blood/fluid

3. proper-sized container (blood vessels appropriately constricted to match volume of blood)

ischemic disease

disease causing decreased blood flow to one or more portions of myocardium

atherosclerosis

• buildup of calcium & cholesterol in walls of blood vessels, obstructing flow & ability to contract/dilate

• often the cause of low blood flow to myocardium

thromboembolism

• blood clot floating through blood vessels until it reaches an area too narrow to pass

• often caused by broken-off piece of plaque in atherosclerotic wall

• may lead to hypoxia in tissues downstream of clot

• may result in AMI or cardiac arrest

cardiac arrest

complete termination of heart’s ability to pump

controllable risk factors of AMI

• cigarette smoking

• high blood pressure

• elevated cholesterol level

• elevated blood glucose level (diabetes)

• lack of exercise

• obesity

• stress

• excessive alcohol

• poor diet

uncontrollable risk factors of AMI

• older age

• family history

• race

• ethnicity

• male sex

acute coronary syndrome (ACS)

• group of symptoms caused by myocardial ischemia

• caused by reduced supply of O₂ & nutrients to heart

• i.e. angina pectoris, AMI

angina pectoris

• temporary chest pain from inadequate O₂

• heart’s need for O₂ exceeds its supply

• occurs often during periods of physical/emotional stress, large meals, sudden fear

• symptoms include crushing, squeezing pain in midportion of chest under sternum

• usually lasts between 3-8 min, rarely longer than 15 min

• assume the worst & treat like AMI

• treatment includes stopping strenuous activity, administering O₂, administering NTG

unstable angina

pain/discomfort in chest of coronary origin occurring in absence of significant increase in myocardial demand; associated w/ very high risk of spontaneous AMI if left untreated

stable angina

pain/discomfort in chest of coronary origin occurring in response to exercise/strenuous activity

AMI

• pain signals actual death of cells in myocardium where blood flow is obstructed

• more often in larger, thick-walled left ventricle (requires more blood/O₂ than right ventricle)

• 30 min after blood flow is cut off, some cells begin to die

• 2 hrs after, upwards of ½ of cells in area can be dead

• 4-6 hrs after, more than 90% of cells are dead

• treatment includes thrombolytic meds/angioplasty to prevent permenant damage if done within first few hrs of onset of symptoms

AMI- signs/symptoms

• sudden onset of weakness, nausea, sweating w/o obvious cause

• chest pain, discomfort, pressure often crushing/squeezing, does not change w/ each breath

• pain, discomfort, pressure in lower jaw, arms, back, abdomen, neck

• irregular heartbeat & syncope

• SOB or dyspnea (blood backing up)

• nausea/vomiting

• pink, frothy sputum (possible pulmonary edema) (blood sitting in lungs)

• sudden death

AMI- pain

differences from angina

• possibly caused by exertion; can occur at any time w/o exertion

• does not resolve in few minutes; can last 30 min to several hours

• possibly relieved by rest or nitroglycerin

pts that are most likely to minimize symptoms

male pts

common pts who will not experience pain during AMI

• geriatric

• women

• diabetics

presents as fatigue, mild discomfort (labeled as indigestion)

AMI- physical findings

• general appearance- frightened, diaphoretic, pale/mottled skin (poor circulation), cyanotic (poor oxygenation)

• pulse- increased/irregular rate; dependent on area affected

• blood pressure- decrease due to diminished cardiac output & capability of left ventricle

• respiration- usually normal unless CHF occurring; become rapid/labored

• mental status- often confused/agitated; overwhelming feeling of impending doom due to decreased blood/O₂

AMI- serious consequences

• sudden death

• cardiogenic shock

• congestive heart failure

ventricular tachycardia

• rapid heart rhythm (150-200 bpm)

• electrical activity starts in ventricle instead of atrium

• does not allow adequate time for left ventricle to fill w/ blood between beats (pumps less volume, BP may fall, pulse may be absent)

• pt may become weak, lightheaded, unresponsive

• existing chest pain may worsen or become present

• may deteriorate into ventricular fibrillation

ventricular fibrillation

• disorganized, ineffective quivering of ventricles preventing blood from pumping through body

• pt becomes unconscious within seconds

• only treatment is defibrillation (if defibrillator not available, provide CPR until defibrillator arrives)

asystole

absence of all heart electrical activity; may occur within minutes w/o CPR; most pts will die

congestive heart failure (CHF)

• occurs any time after myocardial infarction, heart valve damage, or consequence of long-standing hypertension

• leads to increased HR & enlargement of left ventricle to increase amount of blood pumped per minute

• blood backs up into pulmonary veins (increasing pressure in capillaries of lungs, potentially leading to PE)

• in right-sided heart failure, blood backs up into venae cavae, leading to edema in lower extremities (dependent lividity) or distention of neck veins (i.e. JVD)

• left-side failure often leads to right-side failure

hypertensive emergencies

• systolic BP >180 mmHg in presence of impending/progressive organ damage

• signs/symptoms include sudden/severe headache, strong bounding pulse, tinnitus, nausea/vomiting, dizziness, warm skin, nosebleed, altered mental status, spontaneous PE

  • chronic hypertension pts may not have signs/symptoms

• treatments include positioning comfortably w/ head elevated, monitoring BP regularly, transporting rapidly,

• consider ALS if transport time/distance is lengthy

aortic aneurysm

weakness in wall of aorta; aorta dilates at weakened point, making it susceptible to rupture

dissecting aneurysm

• inner layers of aorta become separated, allowing blood to flow between layers at high pressures

• signs/symptoms include very sudden chest pain in anterior part of chest/back between shoulder blades, differing BP between arms, diminished pulses in lower extremities

SAMPLE questions

• “have you ever had a heart attack?”

• “have you been told you have heart problems?”

  • “have you ever been diagnosed w/ angina, heart failure, heart valve disease, or an aneurysm?”

  • “have you ever had high BP?”

  • “do you have any respiratory diseases such as emphysema, chronic bronchitis?”

  • “do you have diabetes or any problems w/ blood sugar?”

  • “have you ever had kidney disease”

• “do you have any risk factors for coronary artery disease?”

  • “is there family history of heart disease?”

  • “do you currently take any medications?”

treatment of pt w/ chest pain/discomfort begins w/:

proper positioning (supine, sitting up (more common), loosening tight clothing, comfortable position)

treatment for chest pain/discomfort

• position comfortably

• administer O₂ & continually reassess O₂ saturation & respiratory status

  • mild dyspnea- nasal canula

  • severe dyspnea- NRB

  • unconscious/obvious respiratory distress- BVM

  • PE- CPAP

  • keep O₂ saturation between 95-99%

after giving NTG, reassess BP within:

5 min

key points of administering NTG:

• wear gloves

• check condition, prescription, expiration date of NTG

• obtain permission from med control

• may lose potency over time or before expiration, especially if exposed to light/heat

  • if potency lost, pt may not experience fizzing/burning sensation when tablet placed under tongue, or headache

if pt has NTG patch & is hypotensive/in cardiac arrest:

remove patch before using AED

lead V1

4th intercostal space, right sternal border; ventricular septum

lead V2

4th intercostal space, left sternal border; ventricular septum

lead V3

between V2 & V4; anterior wall of left ventricle

lead V4

5th intercostal space, midclavicular line; anterior wall of left ventricle

lead V5

lateral to V4 at anterior axillary line; lateral wall of left ventricle

lead V6

lateral to V5 at midaxillary line; lateral wall of left ventricle

guides in maintaining correct lead placement:

• shave body hair if necessary

• remove oils/dead tissues by rubbing site w/ alcohol swab prior to application (may need to be repeated if pt is very sweaty, as many cardiac pts are)

• attach electrodes prior to EKG cable placement

pt positioning for EKGs

supine if possible or in semi-fowler position if pt has difficulty breathing when supine; arms relaxed at side, feet uncrossed

coronary artery bypass graft

blood vessel from chest/leg sewn directly from aorta to coronary artery beyond point of obstruction

percutaneous transluminal coronary angioplasty

dilates coronary using stent/tiny balloon inflated inside narrowed coronary artery (stent is left permanently while balloon is removed)

effects of pacemaker malfunction

dizziness/weakness due to decreased heart rate

automatic implantable cardiac defibrillators (AICD)

• attached directly to heart, continuously monitor rhythm

• delivers shocks as needed

• electricity is low & has no effect on rescuers

• common in survivors of cardiac arrest due to VF, high risk for cardiac arrest

external defibrillator vest

• temporary alternative to AICD

• built-in monitoring electrodes & defib pads worn under clothing

• provides alerts/voice prompts when dangerous rhythm is detected/before shock delivered

• uses high-energy shocks similar to AED (clear pt)

• blue gel under defib pads indicate device has already delivered at least one shock

• if in cardiac arrest, keep in place unless interfering w/ CPR

  • if necessary to remove, remove battery from monitor then remove vest

left ventricular assist devices (LVADs)

• enhance pumping function of left ventricle in pts w/ severe heart failure or pts who need temporary boost due to MI

• most common ones have internal pump unit & external battery pack (almost always continuous)

• pt will not have palpable pulses

cardiac arrest

complete cessation of cardiac activity; absence of carotid pulse

impedance

resistance of body to flow of electricity; causes cells to defibrillate

advantages of AED

• fast

• delivers most important treatment for VF

• easy to operate (ALS operators do not need to be present)

• shock can be given through remote, adhesive defib pads (safe to use)

• transmission of electricity more efficient than manual pads

true/false: not all pts in cardiac arrest require electrical shock

true

pulseless electrical activity

• state of cardiac arrest existing despite organized electrical complex

• defib may make it worse (perform CPR instead)

defib works best if it takes place within ___ of the onset of a cardiac arrest

2 min

to prevent AED from not being able to distinguish other movements from VF:

only apply AED to pulseless, unresponsive pts & stay clear of them

main legal risk in using AED:

failure to deliver shock when one was needed

3 most common errors when using AED

• failure of AED to shock VF

• applying AED to moving, squirming, transporting pt

• turning off AED before analysis/shock complete

operator errors when using AED

• failing to apply AED to pt in cardiac arrest

• not pushing analyze/shock buttons when AED advises to

• pushing power button instead of shock button when shock advised

• failure to deliver shock due to malfunctioning battery (commonly due to improper maintenance)

• applying AED to responsive pt w/ rapid heart rate

if ROSC is achieved:

• check pt’s breathing

  • if adequate, give O₂ via NRB

  • if not adequate, give O₂ via BVM attached to O₂, 10 breaths/min, O₂ saturation 95-99%

• assess blood pressure

• determine extent to which they can follow simple commands

• immediately begin transport

true/false: best chance for pt survival occurs when pt is resuscitated where found (unless scene unsafe)

true

if ALS not responding to cardiac arrest & local protocols agree, begin transport when

• pt regains pulse

• 6-9 shocks have been delivered

• AED gives three consecutive messages that no shock is advised on pulseless pt

steps for cardiac arrest & pulseless pt during transport:

1. stop vehicle

2. perform CPR if AED not immediately ready

3. request ALS support or other resources

4. analyze rhythm

5. deliver shock if indicated, immediately resume CPR

6. continue resuscitation according to protocol

steps for pt w/ chest pain & suddenly becomes unconscious during transport:

1. check for pulse

2. stop vehicle

3. perform CPR if AED not immediately ready

4. analyze rhythm

5. deliver shock if indicated, immediately resume CPR

6. begin compressions, continue resuscitation according to protocol

When an electrical impulse reaches the AV node, it is slowed for a brief period of time so that:

blood can pass from the atria to the ventricles

When the myocardium requires more oxygen:

the arteries supplying the heart dilate

The right coronary artery supplies blood to the:

right ventricle & inferior wall of the left ventricle

The descending aorta divides into the two iliac arteries at the level of the:

umbilicus

Which of the following is the MOST reliable method of estimating a patient's cardiac output?

Assess the heart rate & strength of the pulse

The posterior tibial pulse can be palpated:

behind the medial malleolus, on the inside of the ankle

Ischemic heart disease is defined as:

decreased blood flow to one or more portions of the myocardium

An acute myocardial infarction (AMI) occurs when:

myocardial tissue dies secondary to an absence of oxygen

Acute coronary syndrome (ACS) is a term used to describe:

a group of symptoms that are caused by myocardial ischemia

Prompt transport of a patient w/ a suspected AMI is important because:

the patient may be eligible to receive thrombolytic therapy

Common signs & symptoms of AMI include all of the following, EXCEPT:

pain exacerbated by breathing

Sudden death following AMI is MOST often caused by:

ventricular fibrillation

Which of the following cardiac dysrhythmias has the greatest chance of deteriorating into a pulseless rhythm?

Ventricular tachycardia

Ventricular tachycardia causes hypotension because:

the left ventricle does not adequately fill w/ blood

Cardiogenic shock following AMI is caused by:

decreased pumping force of the heart muscle

You are dispatched to a residence for a 56-year-old male w/ an altered mental status. Upon arrival at the scene, the patient's wife tells you that he complained of chest pain the day before, but would not allow her to call EMS. The patient is semiconscious; has rapid, shallow respirations; & has a thready pulse. You should:

begin ventilatory assistance

A 67-year-old female presents w/ difficulty breathing & chest discomfort that awakened her from her sleep. She states that she has congestive heart failure, has had two previous heart attacks, & has been prescribed nitroglycerin. She is conscious & alert w/ adequate breathing. Her blood pressure is 94/64 mm Hg & her heart rate is 120 beats/min. Treatment for this patient includes:

placing her in an upright position

Which of the following signs is commonly observed in patients w/ right-sided heart failure?

Dependent edema

In contrast to AMI, a dissecting aortic aneurysm:

often presents w/ pain that is maximal from the onset

Upon arriving at the residence of a patient w/ a possible cardiac problem, it is MOST important to:

assess the scene for potential hazards

A 49-year-old male presents w/ an acute onset of crushing chest pain & diaphoresis. You should:

assess the adequacy of his respirations

A 66-year-old female w/ a history of hypertension & diabetes presents w/ substernal chest pressure of 2 hours' duration. Her blood pressure is 140/90 mm Hg, her pulse is 100 beats/min & irregular, her respirations are 22 breaths/min, & her oxygen saturation is 92%. The patient does not have prescribed nitroglycerin, but her husband does. You should:

administer oxygen, give her 324 mg of aspirin, & assess her further

Which of the following is LEAST important when obtaining a medical history from a patient complaining of chest discomfort?

Family history of hypertension

It would be MOST appropriate for a patient to take his or her prescribed nitroglycerin when experiencing:

chest pain that does not immediately subside w/ rest

Most patients are instructed by their physician to take up to _______ doses of nitroglycerin before calling EMS.

three

Which of the following is the MOST likely cause of artifact on an ECG tracing?

Excessive movement of the patient

Which of the following is NOT a common sign or symptom associated w/ malfunction of an implanted cardiac pacemaker?

Rapid heart rate