The biphasic defibrillator manufacturer should display the effective biphasic dose range on the face of the device. If you do not know the effective biphasic dose range of the device, deliver __________ for VF or pulseless VT.
200 J
Biphasic defibrillators use a variety of waveforms, each of wich is effective for terminating VF over a specific dose range. It is reasonable to use selected energies of ___________ with a rectilinear waveform.
120 J
If you are not sure whether or not the patient has a pulse, you should begin cycles of compressions and ventilations.
True
What are some findings on the ECG indicative of pericarditis?
ST elevation may be present in most or all leads, and the T wave itself appears elevated off the baseline
What are some findings indicative of early repolarization?
"smiley" ST elevation; look for a "notched" J point; this is normal in some people, so condsider it if pt is asymptomatic
What is Brugada syndrome?
Hereditary syndrome that can cause SCA in pts without heart disease; look for RBBB with ST elevation in v1 to V3 and "sloping" morphology of ST segment
What is Wellens syndrome?
Pattern of T-wave changes indicative of critical LAD lesion; look for marked T wave inversion or biphasia in V2 and V3
What is long QT syndrome?
QT interval greater than 1/2 the R to R when the rate is 60-100
What ECG findings characterize a pulmonary embolus?
S1Q3(inverted T)3 syndrome; right axis deviation; ST depression in II; T wave inversion V1-V4; RBBB
What happens during defibrillation if the paddle positions are switched?
Defibrillation will occur as usual
After delivering five shocks, what will an implantable cardioverter-defibrillator do in a persistent VTach or VFib?
It will not deliver any more shocks until a slower rate is restored for 30 seconds; after that it can do another cycle of 5
A patient is in pulseless VTach. Two shocks and one dose of epi have been given. The next drug/dose to anticipate to administer is?
Amiodarone 300mg
After two attempts at IV access in a patient in cardiac arrest, what route should you consider next?
IO
Pt. is in refractory VFib. CPR is in progress and shocks have been given. Pt. has received 1 dose of epi and an antiarrhythmic drug. What drug should you expect to administer next?
Second dose of epi
What rhythm is magnesium indicated in for cardiac arrest?
pulseless VTach suspected to be Torsades
A pt. has been resuscitated from cardiac arrest. During resuscitation 300mg amiodarone was administered. Now the pt. develops severe chest discomfort, is diaphoretic, and BP is 80/60 mmHG. ECG is showing sinus rhythm with multifocal PVCs. What is the next indicated action?
Amiodarone 150mg
A pt. with an acute MI had resolution of chest pain with 3 doses of nitro. BP is 104/70. Which intervention is most important, reducing in-hospital and 30-day mortality?
Reperfusion therapy
What three drugs are used frequently in the early management of acute cardiac ischemia (besides oxygen)?
Aspirin, nitro, and morphine
ET tube has been attempted for a pt. in respiratory arrest. Epigastric sounds are heard but no breath sounds, and O2 sats stay low. What is the most likely explanation for these findings?
Esophogeal intubation
You prepare to cardiovert an unstable pt. with tachycardia. The monitor is in sync mode. Pt. suddenly becomes unresponsive and pulseless. You charge to 200J and press shock, but nothing happens. Why?
You cannot deliver unsynchronized shocks in sync mode
Second and subsequent defibrillations for pediatric patients should occur at what setting?
4J/kg
Pt. is in cardiac arrest. VFib has been refractory to an initial shock. What drug/dose should be administered first by IV/IO?
epinephrine 1:10000 1mg
When do we treat a bradycardic rhythm?
When the pt. is severely symptomatic/unstable
What is the initial dose of atropine for a patient with a pulse of 42bpm?
0.5mg
When in the cardiac cycle does synchronized cardioversion deliver energy?
10 ms after the peak of the R wave
A pt. has coded and recurrent episodes of VTach are seen on the ECG. Notes about the 12-lead state that his QT interval is top-normal to slightly prolonged. He has received 2 doses of epi and 1 of amiodarone. What should you give him next?
Mag 1 to 2 g diluted in 10mL D5W over 5-10 min
Define left ventricular failure.
The left ventricle fails to work as an effective forward pump causing a back-pressure of blood into the pulmonary circulation
Define paroxysmal nocturnal dyspnea.
characterized by sudden attacks of dyspnea, profuse diaphoresis, tachycardia, and wheezing that awakens a person from sleep; often associated with left ventricular failure and pulmonary edema
What position should you place a pt in who has severe pulmonary edema and why?
Sitting with the legs dependent; increases lung volume and vital capacity and decreases venous return to the heart and decreases work of breathing
What three medications besides oxygen can be used to treat severe pulmonary edema?
Nitro, Lasix, morphine
Define right ventricular failure.
The right ventricle fails to work as an effective forward pump causing back-pressure of blood into the systemic venous circulation
What are some diseases associated with causing right ventricular failure?
chronic hypertension
COPD
PE
valvular heart disease
right-sided infarction
pulmonary hypertension
Right ventricular failure is often chronic but not usually a medical emergency. When can it be an emergency?
If associated with pulmonary edema or hypotension
What can hypotension caused by right ventricular failure often mimic?
cardiogenic shock; in this case, fluid administration is essential to help normalize left ventricular filling
Define cardiogenic shock.
the most extreme form of pump failure; left ventricular function is so compromised that the heart cannot meet the metabolic needs of the body
Cardiogenic shock is present when shock persists after...
dysrhythmias and volume deficits are corrected
Cardiogenic shock is usually caused by what?
extensive MI usually involving more than 40% of the left ventricle or by diffuse ischemia
What is the mortality rate of cardiogenic shock?
70% or higher
What are the signs and symptoms of cardiogenic shock?
SXS of MI
acidosis
altered LOC
cool, clammy, ashen, or cyanotic skin
hypoxemia
profound hypotension (systolic usually less than 80)
pulmonary congestion
sinus tachycardia or other dysrhythmias
tachypnea
Define cardiac tamponade.
impaired diastolic filling of the heart caused by increased intrapericardial pressure and volume
What are some causes of cardiac tamponade?
cancerous growth or infection (some Lymphomas)
trauma
CPR
rental disease
hypothyroidism
What are some SXS of cardiac tamponade?
faint or muffled heart sounds
narrowing pulse pressures
pulsus paradoxus
JVD
hypotension
tachycardia
Define aneurysm.
means "dilation of a vessel"; nonspecific term
What are some common causes of aneurysms?
atherosclerotic disease (most common)
infectious disease (primarily syphilis)
traumatic injury
genetic disorders (Marfan's)
What is the most common site for an abdominal aortic aneurysm?
below the renal arteries and above the branching of the common iliac arteries
What sex and age group are most at risk for abdominal aortic aneurysm?
males between the ages of 60 and 70
True or false: an abdominal aneurysm is usually symptomatic.
False - can be asymptomatic as long as it is stable
What SXS will a patient often have with a rupturing aneurysm?
syncope followed by hypotension with bradycardia even though they have a large amount of blood loss
How do we treat a pt. with a leaking or ruptured aortic aneurysm?
Gentle handling
oxygen
cardiac monitoring (could precipitate an MI)
IV fluids (titrated to mild hypotension to prevent further rupture; if ruptured, very aggressive)
call ahead to facility with findings
Define acute aortic dissection.
separation of the arterial wall of the aorta
What are some factors that can lead to aortic dissections?
systemic hypertension
atherosclerosis
congenital defects
cystic medial necrosis
trauma
pregnancy
What sex and race are at higher risk for aortic dissections?
Males and African Americans
Describe how a dissection of the aorta occurs.
Small tear forms in the intimal layer of the vessel wall; allows blood to move between the inner and outer layers; results in formation of a hematoma; this can rupture through the outer wall at any time
What is the most common site of an aortic dissection?
the ascending aorta
What are the most common SXS of an aortic dissection?
severe pain in the back, epigastrum, abdomen, or extremities
"ripping" "tearing" or "sharp and cutting" between the scapulae
syncope
pericardial tamponade
pallor
peripheral cyanosis
diaphoresis
reduced pulses
How do we manage a pt. with an aortic dissection?
gentle handling
decrease anxiety
high flow O2
IV TKO
analgesia if indicated by protocol
What are the most common causes of acute arterial occlusions?
trauma; often associated with long bone fractures
embolus
thrombosis
What percentage of peripheral emboli originate in the heart?
90%; this means a history of cardiac disease favors a diagnosis of embolic occlusion
What are the most common sites of embolic occlusions?
abdominal aorta
common femoral artery
popliteal artery
carotid artery
brachial artery
mesenteric artery
What are the SXS of acute arterial occlusions?
pain in the extremity that may be severe and sudden
absence of pain due to paresthesia
pale, mottled, or cyanotic skin
lowered skin temperature distal to the occlusion
changes in sensory and motor function
diminished or absent pulse distal to the occlusion
slow cap refill
possible shock
What are some risk factors for DVTs?
recent surgery
lower extremity trauma
advanced age
recent MI
inactivity
bedrest
CHF
cancer
obesity
birth control pills
What are the SXS of a DVT?
pain
edema
warmth
erythema or bluish discoloration
tenderness
How do we manage a DVT?
immobilization and elevation of the extremity
Define hypertension.
a resting BP consistently greater than 140/90mmHg
What conditions are associated with chronic hypertension?
left ventricular hypertrophy
cerebral hemorrhage and stroke
MI
renal failure
thoracic or abdominal aneurysms
What is a physiological response that the heart does to compensate for chronic hypertension?
englarges the muscle
Define a hypertensive emergency.
condition in which an increase in BP leads to significant, irreversible damage to organs
What are the organs most likely to be at risk in a hypertensive emergency?
brain
heart
kidneys
What are the SXS of a hypertensive emergency?
paroxysmal nocturnal dyspnea
SOB
AMS
vertigo
headache
epistaxis
tinnitus
changes in visual acuity
N/V
seizures
What are the six types of hypertensive emergencies?
myocardial ischemia with hypertension
aortic dissection with hypertension
pulmonary edema with hypertension
hypertensive intracranial hemorrhage
toxemia
hypertensive encephalopathy
What is hypertensive encephalopathy?
elevated BP that concurrently raises ICP and produces brain damage; loss of integrity of blood brain barrier; fluid exudation into brain tissue
What are the SXS of hypertensive encephalopathy?
Initial- severe headache, nausea, vomiting, aphasia, hemiparesis, and transient blindness
Later- seizures, stupor, coma, and death
How do we manage a pt. with hypertensive encephalopathy?
supportive care
calming the pt
oxygen
IV TKO
ECG
rapid transport
if transport is delayed, MCEP may advise nitro for vasodilation
What time frames for CPR and ACLS show the greatest survival to hospital discharge for patients in cardiac arrest?
CPR within 4 minutes and ACLS management within 8 minutes
Artificial circulation (CPR) only generates what percentage of normal cardiac output?
20-30%
What is the purpose of defibrillation?
to depolarize at least 75% of the myocardial cells to allow a normal pacemaker of the heart to take over
Define impedance.
resistance to current by the chest wall; determined by body size, bone structure, skin properties, underlying health conditions
As a rule, what percentage of stored energy approximates the number of joules delivered to the patient?
80%
What is the initial defibrillation Joule setting on a monophasic machine?
360J
What is the initial defibrillation Joule setting on a biphasic machine?
generally 120-200J
What is the initial energy setting for pediatrics?
2J/kg
An implantable cardioverter defibrillator delivers a shock when a monitored ventricular rate exceeds the preprogrammed rate. What is the amount of energy it delivers?
6J to 30J; usually takes 10-30 seconds to charge before another shock is delivered
While in sync mode, a marker should be displayed on the monitor at the R wave. If you do not see the markers, what should you do?
Try viewing another lead; the machine may not be able to sense when it is supposed to be shocking
Define demand pacing.
The pacemaker delivers electrical stimuli only when needed
When pacing a patient, you should monitor the patients BP and pulse rate constantly. On which side of the body should you do this?
the right side; it reduces interference from muscle artifact caused by the electricity
What are the four classes of heart failure?
Class I - Pt is not limited in normal activity
Class II - Ordinary physical activity causes fatigue
Class III - Marked limitation of normal activity
Class IV - Symptoms evident at rest
What type of natriuretic factor is released during heart failure?
Atrial; released when things are over-stretched; natural antagonist to RAAS
What is the renin-angiotensin-aldosterone system?
Activated when kidneys aren't being sufficiently perfused; causes decreased liver perfusion which leads to a release of Angiotensin I and II
Angiotensin II stimulates the release of ADH from the pituitary gland
Arterioral vasoconstriction results which increases BP
Aldosterone is secreted to retain salts and H20 and increases sympathetic activity
Which type of aortic aneurysms is most serious according to the Debakey vs. Stanford scale? Rate them in order.
Type I most serious; then Type II, then IIIb, then IIIa
What are some predisposing factors for venous thromboses?
history of trauma
sepsis
stasis
recent immobilization
pregnancy
birth control pills
malignancy
coagulopathies
smoking
varicose veins
What is a common test/sign used to determine the presence of a venous thrombisis?
Homan's sign - positive for pain on engagement of one calf muscle as compared to the other
If a hypothermic patient is pulseless and apneic, what should your treatment include?
Start CPR
Defibrillate
IV access
A/W access
If mild to moderate hypothermia, how should we administer our medications and defibrillations?
Same dosages, but longer intervals in between and repeat defibrillation after temperature increases
If severe hypothermia, how does our treatment of a pulseless apneic patient change?
Withold IV medications, limit to one defibrillation shock, transport
