ACLS 1 Answers & Explanations.pdf

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ACLS Practice Test 1
Answers & Explanations
1. d. 26. b.
2. b. 27. a.
3. d. 28. c.
4. a. 29. d.
5. b. 30. b.
6. c. 31. a.
7. d. 32. b.
8. a. 33. b.
9. b. 34. c.
10. b. 35. a.
11. d. 36. d.
12. c. 37. d.
13. a. 38. d.
14. d. 39. d.
15. a. 40. b.
16. c. 41. a.
17. b. 42. b.
18. d. 43. b.
19. b. 44. c.
20. b. 45. c.
21. c. 46. a.
22. a. 47. d.
23. c. 48. a.
24. c. 49. a.
25. c. 50. c.
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1.d.
If breath sounds cannot be auscultated, the ET tube is likely in the esophagus. It should be
removed immediately, and the patient should be ventilated with 100% oxygen using a bag-mask
device for 1 minute before re-attempting intubation.
2.b.
In the Adult Post-Cardiac Arrest Algorithm, PETCO2 should be kept between 35 and 40 mm Hg.
Other recommendations include systolic BP ≥ 90 mm Hg and O2 saturation ≥ 94%.
3.d.
See the algorithm for tachycardias. Of the choices, emergency synchronized cardioversion is
indicated only for choice d. Choice a. represents PEA, and thus CPR and epinephrine 1 mg every
3 minutes is indicated. In choice b., the patient is stable so immediate treatment is not necessary.
Non-emergent treatment for atrial fibrillation may include ventricular rate control,
anticoaguation, and chemical or electrical cardioversion. Choice c. involves identifying and
treating the cause.
4.a.
Potential reversible causes of PEA include the 5H's and 5T's, but most notably tension
pneumothorax, cardiac tamponade, hypovolemia, and hypothermia. The other choices are not
indicated in PEA—see the PEA Algorithm. Defibrillation is only indicated for VF and unstable
VT. In the ACLS Algorithm, atropine and/or TCP would be indicated only for symptomatic
bradycardia.
5.b.
The rhythm strip shows supraventricular tachycardia (SVT) at a rate of 160 beats/min, causing
decreased cardiac output and thus decreased blood pressure and consequently lightheadedness.
The immediate treatment is adenosine 6 mg IV as rapidly as possible, followed by a rapid saline
flush. Should this fail to convert the rhythm to NSR, the same procedure should be tried with 12
mg of adenosine. Metoprolol and diltiazem are not first line agents for SVT. NS bolus is not
indicated in this scenario. Vagal maneuvres may be tried before adenosine, while awaiting IV
access.
6.c.
There have been several reports of fires from sparks from poorly applied pads or paddles in
oxygen-rich environments. Interruptions in chest compressions should be absolutely minimized
—they should continue while the defibrillator is charging and immediately after the shock.
Generally, rhythm and pulse checks should only be done just before defibrillation, i.e. about
every 2 minutes.
7.d.
Gastric lavage may be indicated for patients who have ingested a potentially lethal amount of
drug or toxin within the preceding 1 hour. Beyond 1 hour, gastric lavage and/or activated
charcoal are ineffective.
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8.a.
Interruptions in chest compressions must be kept to a minimum. They must be continued right up
until the moment of electric shock. Another key to successful defibrillation is to lower thoracic
impedance (resistance to electric current) as much as possible. Ways to do this include the use of
adhesive pads or firm pressure with paddles, use of electrode gel, defibrillating in end-expiration,
possibly shaving areas of excessive hair, and avoiding placement on the breast.
9.b.
As for all emergencies, maintenance of the airway and adequate oxygenation are the top
priorities. Before fibrinolytic therapy is given, a CT of the head must be done, the onset of stroke
must be within the accepted time frame, and there should be no contraindications. Thus, it is also
important to determine as accurately as possible when the patient was last "normal" or at
“baseline.” Antihypertensives are given if fibrinolytic therapy is contemplated and BP is >
185/110; otherwise, their use depends on the particulars of the case. Surgical clipping of an
aneurysm is done in select cases where intracranial bleeding is due to such an aneurysm; it is not
used to treat an ischemic stroke.
10.b.
The rhythm is 3
rd
degree AV block, since the P waves are completely dissociated from the QRS
complexes. However, the most important fact is the patient has no pulse. This means PEA.
According to the PEA Algorithm, CPR should be continued and epinephrine 1 mg should be
given every 3 minutes. This also applies if the patient is in asystole. Atropine is indicated for
symptomatic bradycardia with pulse—this patient is pulseless. The norepinephrine infusion
might be administered upon ROSC if the patient were hypotensive. An advanced airway has
lower priority than CPR and epinephrine.
11.d.
Basic life support (BLS) essentially consists of ascertaining unresponsiveness, calling for help,
positioning the patient, CPR, and defibrillating as early as possible if indicated. It also includes
early recognition and management of myocardial infarction and stroke. The other choices are in
the realm of ACLS.
12.c.
The most likely cause for this problem is a faulty connection. All connections should be checked
and the rhythm reanalyzed. Turning the AED off and Waiting 30 seconds is obviously wasting
too much valuable time, as is waiting for EMS to arrive. If the AED still does not work, you
should start chest compressions.
13.a.
The patient has bradycardia with poor perfusion. According to the Bradycardia Algorithm, after
trying atropine 0.5 mg IV and while awaiting TCP, epinephrine 2 to 10 mcg/min or dopamine 2
to 10 mcg/kg/min may be tried. Of course, always consider and treat the underlying causes (5H's
& 5T's). Epinephrine increases cardiac output and blood pressure. Amiodarone is an
antiarrhythmic, but is not indicated for bradycardia. Magnesium is used to treat hypomagnesemia
and torsades de pointes. Adenosine is used to treat SVT.
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14.d.
The second dose of adenosine for patients in refractory but stable narrow-complex tachycardia
(i.e. SVT) is 12 mg rapid IV push followed immediately by a rapid IV flush. This can be
repeated one more time if necessary. If the SVT is unstable, synchronized cardioversion at 50 J
to 100 J is indicated.
15.a.
A large uterus tends to compress the inferior vena cava, inhibiting venous return, which reduces
cardiac output. This situation may be mitigated by manually displacing the uterus to the left
and/or tilting the patient to the left either with a foam wedge or a rescuer's knees. Defibrillation
and essentially all the measures of BLS and ACLS remain the same in pregnant patients. During
defibrillation, an insignificant amount of current flows through the fetus. There is no benefit to
elevating the patient's head during a cardiac arrest.
16.c.
Vasopressin 40 units IV or IO push may be given once instead of the first or second dose of
epinephrine. At a high dose of 40 U, vasopressin, like epinephrine, causes vasoconstriction
outside the heart, which causes diastolic BP to increase, which increases coronary perfusion.
17.b.
Patients in cardiac arrest have decreased lung compliance, so increased airway pressures are
needed for ventilation. Thus, pop-off valves should not be a component of bag-mask devices.
18.d.
The rhythm is ventricular tachycardia (rate is just under 300/min). There is no pulse, so
according to the algorithm for pulseless VT, the patient should be defibrillated as soon as
possible. If after defibrillation there is no change, epinephrine 1 mg IV or IO every 3 minutes
should be given. And, following this, amiodarone 300 mg IV or IO may be given if necessary.
All the while, CPR must be continued with as little interruptions as possible. Choice c. relates to
unstable VT with a pulse.
19.b.
Choice B is essentially the BLS Algorithm. It has changed from “ABC” to “CAB,” and the use
of the AED as soon as it is available. When adults have a cardiac arrest, the initial oxygen
content of the blood is typically normal, so compressions alone will likely adequately oxygenate
the heart and brain for the first few minutes.
20.b.
The Acute Coronary Syndromes Algorithm prescribes that, in patients with chest discomfort
suggestive of ischemia, initial actions include the following: oxygen be given, IV access
established, cardiac monitor placed, and acetylsalicylic acid (ASA) and nitroglycerin (NTG) be
given. Morphine is given only if the NTG does not relieve the pain. Contraindications to NTG
include systolic BP < 90, HR < 50 or >100, recent PDE inhibitor (e.g. Viagara®) use, and
inferior or RV infarction. Contraindications to morphine include hypotension and allergy. A
fibrinolytic is indicated only in specific circumstances, e.g. confirmed STEMI, within 12 hours of
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onset, no contraindications, and when percutaneous coronary intervention (PCI) would not be
optimal.
21.c.
Compressions should be ≥ 100/min, not 80/min. They should also be ≥ 5 cm (2 inches), and
allow for complete chest recoil. The other responses would also indicate that the CPR delivered
is effective.
22.a.
In the Adult Post-Cardiac Arrest Algorithm, systolic BP should be kept ≥ 90 mm Hg. Other
recommendations include PETCO2 between 35 and 40 mm Hg and O2 saturation ≥ 94%.
23.c.
The recommended IV fluid (normal saline or Ringer's lactate) bolus dose for a patient who
achieves ROSC but is hypotensive is 1 L to 2 L.
24.c.
Continuous waveform capnography is the most reliable method of confirming and monitoring
correct placement of an endotracheal tube. Nevertheless, it should be combined with clinical
assessment. Ventilations should be titrated to a PETCO2 of 40 to 45 mm Hg.
25.c.
Ties that pass circumferentially around the patient's neck may cause obstruction of venous return
from the brain by compressing the jugular veins.
26.b.
The purpose of therapeutic hypothermia during the post-cardiac arrest period is to protect
primarily the brain and also other organs. The rationale is that a lower temperature lowers the
metabolic rate, which lowers the risk of adverse effects from hypoxia and ischemia. A
contraindication to therapeutic hypothermia is when a patient responds appropriately to verbal
commands. This indicates the brain is functioning normally already and protection using
therapeutic hypothermia is not necessary.
27.a.
Synchronized cardioversion is shock delivery timed with the QRS complex. If a shock is
delivered during the relative refractory period, which is the later half of the T wave, there is a risk
of inducing ventricular fibrillation. Synchronized cardioversion is recommended for unstable
supraventricular tachycardia, unstable atrial fibrillation and flutter, and unstable monomorphic
ventricular tachycardia. Sinus tachycardia is managed by treating the cause of it. NSR on
monitor but no pulse is considered PEA and is managed with CPR and epinephrine IV and
treating the cause – cardioversion is not effective.
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28.c.
This question relates to the BLS survey. When you see a collapsed person, first ensure the scene
is safe; then check responsiveness; then check for breathing (you would not actually evaluate
breath sounds with a stethoscope); then activate the emergency response system and get an AED;
then check the carotid pulse. If there is no pulse within 5 to 10 seconds, start chest compressions
and give 2 breaths for every 30 compressions. As soon as an AED is at hand, attach the pads and
provide shocks if indicated. Continue CPR, shocks, and ACLS as appropriate. If, on the other
hand, pulses are present, you would not perform CPR; instead, you would use one of the other
ACLS algorithms. Reviewing the patient's home medications is necessary, but not the initial
priority. Administering sedative drugs would be contraindicated in an unconscious patient.
29.d.
A regular wide-complex tachycardia is likely ventricular tachycardia; less likely is SVT with
aberrant ventricular conduction. You must decide if the patient is stable or unstable. Criteria for
instability are: ischemic chest pain, hypotension, signs of shock, acutely altered mental status,
and heart failure. He has most, if not all, of these. Therefore, synchronized cardioversion at 100
J should be done immediately. You may consider procedural sedation prior to synchronized
cardioversion if it can be executed very quickly. If not, you should cardiovert without it.
Note that this patient has a carotid pulse. If he had no pulse, CPR and defibrillation (not
cardioversion) should be done. A 12-lead ECG should be done soon, but is not the top priority
presently. Amiodarone 150 mg IV over 10 minutes is indicated for stable ventricular tachycardia
– this patient is clearly unstable.
30.b.
The proper ventilation rate for a patient in cardiac arrest who has an advanced airway is 8 to 10
breaths per minute, or one breath every 6 to 8 seconds.
31.a.
In the Suspected Stroke Algorithm, the first tasks are to support the ABC's, administer oxygen if
necessary, perform prehospital stroke assessment, check blood glucose level, and establish when
the patient was last normal. The next step is to do a non-contrast head CT scan to rule out a
hemorrhagic stroke. If there is hemorrhage, a neurosurgeon or neurologist should be consulted.
If there is no hemorrhage, fibrinolytic therapy (i.e. tPA) should be considered. Since the patient
is not hypertensive, an antihypertensive should not be given. In any case, treating hypertension
in the stroke patient is controversial. Since the blood glucose level is within normal limits,
neither glucose nor insulin are required. Since the pulse oximetry reading is > 92% on room air,
supplemental oxygen is contraindicated, because excessive oxygen may cause further brain
damage.
32.b.
Factors to consider when making the decision to terminate resuscitation efforts include:
A “Do Not Resuscitate” order.
Amount of time after collapse before CPR and defibrillation began.
Duration of the resuscitation effort.
Signs of irreversible death (e.g. rigor mortis, dependent lividity, decapitation).
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Comorbidity.
Policies of the healthcare facility.
Low end-tidal carbon dioxide (PETCO2) after 20 minutes of CPR in intubated patients
(e.g. < 10 mm Hg by quantitative waveform capnography).
Resuscitation should not be terminated based on whether or not the arrest was witnessed, the
patient's age, or the absence of return of spontaneous circulation after only 10 minutes of CPR.
33.b.
This an unstable bradycardia. “Bradycardia” because the pulse rate (QRS rate) is 36 to 37 bpm,
which is very slow; and “unstable” because the patient has hypotension, signs of shock, and
acutely altered mental status. So, you would use the Bradycardia with Pulse Algorithm and this
would take you to the point where you would administer Atropine 0.5 mg IV every 3 to 5
minutes. If this were ineffective in increasing the heart rate, you would consider transcutaneous
pacing, dopamine 2 to 10 mcg/kg/min IV, or epinephrine 2 to 10 mcg/min IV. For your
information, the rhythm shown is 3
rd
degree heart block (or complete heart block) since there is
no relationship between the P waves and QRS complexes. Aspirin and nitroglycerin would be
given for an acute coronary syndrome. Amiodarone is an antiarrhythmic used in various
tachyarrythmias.
34.c.
The proper procedure for suctioning an ET tube is as follows:
1. Use a soft, sterile catheter, and use sterile technique to prevent the possibility of
infection.
2.Turn on the suction machine and set vacuum regulator to 80-120 mm Hg if available.
Use only enough pressure to effectively suction since hypoxia and damage to
respiratory mucosa can occur if the suction pressure is too high.
3. Without suction, gently insert the catheter into the ET tube until you feel resistance,
then pull the catheter back 1-2 centimeters.
4.Apply suction and slowly pull the catheter out of the ET tube as you rotate the
catheter between your fingers. Suctioning time should NEVER exceed 10-15
seconds.
5.After suctioning, hyperoxygenate the patient by delivering several deep breaths.
6. Monitor the victim's condition during suctioning, e.g. observe for cyanosis, airway
spasms, cardiac dysrhythmias, and changes in level of consciousness.
Suctioning the mouth is best done with a rigid Yankauer catheter.
35.a.
The use of quantitative waveform capnography in intubated patients who are undergoing CPR
allows for the monitoring of CPR quality. If end-tidal CO2 (PETCO2) is < 10 mm Hg, CPR needs
to be improved. Other indicators of effective CPR are diastolic BP > 20 mm Hg; chest
compressions 5 to 6 cm (2 to 2.4 inches), at a rate of 100-120 compressions/min, with complete
chest recoil between compressions; and minimal interruptions in CPR, with each interruption <
10 seconds.
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36.d.
After about 20 minutes of high-quality resuscitative efforts, you should consider terminating the
efforts (see question 32). Amiodarone 300 mg IV bolus would be considered for VF or pulseless
VT. This patient has asystole. Of course, you would ensure the rhythm was not fine VF by
checking it in at least two leads. Atropine 0.5 mg IV and transcutaneous pacing are part of the
Bradycardia with Pulse Algorithm – these interventions are not indicated for asystole.
37.d.
Details of the three possible routes of vascular access during a cardiac arrest is shown in the table
above. Use of a central line is another route, but is usually only utilized if already in place before
the arrest, because of the length of time needed to insert one. The preferred route of drug
administration during a cardiac arrest is IV, because it is quick and simple. Next is IO, also
because it is quick and simple; however, it is reserved for when an IV cannot be quickly
established. The ET route is used only if an IV or IO cannot be quickly established; thus, it
should rarely be used.
38.d.
This man may have an acute coronary syndrome (ACS). Utilizing the ACS Algorithm, your next
assessment step should be a 12-lead ECG. This would help in the diagnosis of the type of ACS,
and, therefore, determine the treatment. You should also obtain lab tests, including a baseline
troponin; but, this does not have a higher priority than obtaining a 12-lead ECG. A chest x-ray is
of even lower priority, especially since there is no indication of respiratory distress. PETCO2 is
indicated if there is an advanced airway, which is absent in this case.
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39.d.
Providing quality compressions immediately before defibrillation is the only way to ensure the
myocardial cells have the most oxygen available to them possible and the least amount of waste
products of metabolism, thus maximizing the chance of successful defibrillation. Conversely,
pausing chest compressions has the opposite effect, and reduces the chance of successful
defibrillation. Using manual defibrillator paddles with light pressure against the chest would
result in less current reaching the heart, and reduce the chance of successful defibrillation.
Paddles, if used, must be held tightly against the chest. Administering 4 quick ventilations
immediately before a defibrillation attempt also reduces the chance of successful defibrillation by
increasing the impedance (electrical resistance) of the chest, resulting in less current reaching the
heart.
40.b.
The patient has a pulse, so CPR is not necessary. The two major problems are respiratory arrest
and bradycardia. In this situation, “ABC” applies. First ensure an adequate airway by using the
head tilt/chin lift or jaw thrust maneuver. If the patient is still not breathing, provide one breath
every 5-6 seconds (10-12 breaths each minute). Supply oxygen to keep the oxygen saturation ≥
94%. If the bradycardia persists after these interventions, then proceed down the Bradycardia
Algorithm. The next step is Atropine IV 0.5 mg IV, repeating every 3 to 5 minutes as needed, up
to a maximum of 3 mg total. If this does not work, then transcutaneous pacing, epinephrine 2 to
10 mcg/min, or dopamine 2 to 10 mcg/kg/min should be tried.
41.a.
The primary purpose of a medical emergency team (MET) or rapid response team (RRT) is
identifying and treating early clinical deterioration in hospital patients. In-hospital cardiac arrest
is often preceded by physiologic changes – in most cases, up to 8 hours before the arrest.
42.b.
Confusion, in this scenario, is caused by hypoxia, and is an early sign of respiratory failure.
Therefore, intubation is necessary. Other signs of hypoxia include severe agitation, obtundation,
poor muscle tone, and profuse sweating. Wheezing and tachycardia are common in asthma, and
do not necessarily indicate the need for intubation. In respiratory failure, PaCO2 is increased, not
decreased.
43.b.
The rhythm is Torsades de Pointes – likely caused by an overdose of her tricyclic antidepressant.
Although Torsades de Pointes is a type of ventricular tachycardia, it is treated differently. Since
she is not in cardiac arrest, Mg SO4 1 to 2 g IV over 5 to 60 minutes, followed by 0.5 to 1 g IV
per hour should be administered. If she were in cardiac arrest, Mg SO4 1 to 2 g IV bolus should
be administered as well as epinephrine 1 mg IV every 3 to 5 minutes. Currently, amiodarone is
not indicated for Torsades de Pointes.
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44.c.
Sometimes VF can be so fine that it looks flat. Always verify asystole by checking at least two
leads.
45.c.
Before administering fibrinolytic therapy to a patient with chest pain, a team member should run
through the Fibrinolytic Checklist for STEMI to ensure there is a reasonable probability it will be
effective and that there are no contraindications. One of the most important criteria is either ST-
segment elevation or new left bundle-branch block.
46.a.
Usually, a resuscitation team will have one team leader who is responsible for ensuring that the
resuscitation effort flows smoothly and that each task is completed properly. Specific roles
include:
Organizing the team
Monitoring the performance of the team (e.g. monitoring the quality of CPR)
Perform any skills if necessary (however, if certain tasks can be delegated, they should be).
Model appropriate behaviors (i.e. leading by example)
Coach other members of the team as necessary
Focus on provision of exceptional care
Mentor the group by providing a critique of team and individual performances when the
resuscitation is over
Establishing an advanced airway, contacting the patient's family, and administering medications
should ideally be delegated to others who have the necessary skills.
47.d.
In PEA, the ECG may show any rhythm except when there is VF or pulseless VT. By definition,
PEA is present when there are visible complexes on the ECG monitor that should result in a
pulse, but no pulses can be felt. The goal of treatment for PEA is to identify and treat the
underlying cause using the H's and T's. PEA will not respond to shocks.
48.a.
The NIH Stroke Scale would provide the most useful clinical information for diagnosis and
ongoing management of a stroke patient in the ED. It is a validated, reliable, and detailed
measure of stroke severity and prognosis, and is much simpler and quicker than a complete
neurologic examination. The Cincinnati Prehospital Stroke Scale, as the name indicates, is
designed for EMS responders. It is based on only three physical findings: facial droop, arm
weakness, and speech abnormalities. The Hunt and Hess Scale is designed for subarachnoid
hemorrhage, not stroke. The Glasgow Coma Scale is widely used in head trauma and other brain
insults. In stroke patients, it is far less specific and sensitive than the NIH Stroke Scale.
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49.a.
The rhythm is atrial fibrillation. The ventricular rate is rapid at approximately 120 per minute,
which accounts for the patient's symptoms. Since the patient is stable, cardioversion is not
necessary at this time; although it may be done later on an elective basis. At this time, symptom
relief should be provided by slowing the ventricular rate. Diltiazem, metoprolol, and digoxin all
inhibit conduction through the AV node and, therefore, may slow down the ventricular rate.
Adenosine is given for SVT, not atrial fibrillation.
50.c.
For the first shock, the defibrillator was in the “synchronized” mode in order to time the shock
with a QRS complex. When the rhythm changed to VF, there were no QRS complexes anymore,
so no shock was delivered. The “synchronized” mode must be turned off first, then a shock can
be delivered to defibrillate the patient.
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