lOMoAR cPSD| 36357603
lOMoAR cPSD| 36357603
CARDIAC ARREST ULTRA-SOUND SUMMARY- A BETTER
APPROACH TO MANAGING PATIENTS IN PRIMARY NON-
ARRHYTHMOGENIC CARDIAC ARREST
KEYWORDS Summary Cardiac arrest is a condition frequently encountered by physicians in the hospital
Advanced life support setting including the Emergency Department, Intensive Care Unit and medical/surgical wards.
(ALS); This paper reviews the current literature involving the use of ultrasound in resuscitation and
Cardiac arrest; proposes an algorithmic approach for the use of ultrasound during cardiac arrest. At present
there is the need for a means of differentiating between various causes of cardiac arrest, which
Cardiac tamponade;
are not a direct result of a primary ventricular arrhythmia. Identifying the cause of pulseless
Hypovolemia;
electrical activity or asystole is important as the underlying cause is what guides management
Pulmonary embolism;
in such cases. This approach, incorporating ultrasound to manage cardiac arrest aids in the
Pulseless electrical
diagnosis of the most common and easily reversible causes of cardiac arrest not caused by
activity (PEA);
primary ventricular arrhythmia, namely; severe hypovolemia, tension pneumothorax, cardiac
Tension
tamponade, and massive pulmonary embolus. These four conditions are addressed in this paper
pneumothorax;
using four accepted emergency ultrasound applications to be performed during resuscitation of
Ultrasound
a cardiac arrest patient with the aim of determining the underlying cause of a cardiac arrest.
Identifying the underlying cause of cardiac arrest represents the one of the greatest challenges
of managing patients with asystole or PEA and accurate determination has the potential to
improve management by guiding therapeutic decisions.
We include several clinical images demonstrating examples of cardiac tamponade, massive
pulmonary embolus, and severe hypovolemia secondary to abdominal aortic aneurysm.
In conclusion, this protocol has the potential to reduce the time required to determine the
etiology of a cardiac arrest and thus decrease the time between arrest and appropriate therapy.
, lOMoAR cPSD| 36357603
C.A.U.S.E. in primary non-arrhythmogenic cardiac arrest 199
Introduction paper is twofold; first, to review the literature involving
ultrasound and resuscitative conditions. Second, to propose
Cardiac arrest is a condition frequently encountered by a goal oriented approach to the cardiac arrest patient that
physicians in the hospital setting including the Emer- incorporates the use of ultrasound to address the most com-
gency Department, Intensive Care Unit and medical/surgical mon reversible causes of non-arrhythmia cardiac arrest. The
wards. Since the implementation of preventative health name of this new test is C.A.U.S.E., an acronym for cardiac
policy and ACLS, deaths from ventricular fibrillation and arrest ultra sound examination, and whose name has the
ventricular tachycardia have decreased significantly, how- added benefit of reminding the practitioner that the pri-
ever the prevalence of pulseless electrical activity (PEA) and mary goal of their effort in PEA or asystole should be to
asystole have increased.1 Unlike ventricular fibrillation and identify and address the underlying cause. The protocol also
pulseless ventricular tachycardia where the pattern/rhythm serves to organize a process that can at times be chaotic
of electrical activity is the focus of treatment rather than and disorganized. Past studies have shown that increased
the underlying cause, PEA and asystole are corrected by organization during resuscitation increases the likelihood
addressing the underlying cause.2 The importance of identi- of survival.16,17 A similar organizational protocol has been
fying a reversible underlying cause in these forms of cardiac used for the treatment of ventricular arrhythmias using
arrest is of such importance that almost half of the ACLS three-lead electrocardiogram as a diagnostic tool with great
for experienced practitioners manual is dedicated to this success.1,2
topic and its practical application.2 Hughes et al. provided
a list of the etiologies of PEA in the order of frequency and Sonographic applications for cardiac arrest
ease of reversal.3 He lists the top five conditions as hypoxia,
hypovolemia, tension pneumothorax, pericardial tampon-
Ultrasound has been used as an effective diagnostic tool dur-
ade, and pulmonary emboli. These conditions are potentially
ing cardiac arrest and has identified causes of PEA. These
reversible, but the treatment is often invasive and may be
include cardiac tamponade, severe hypovolemia, pulmonary
deadly if mistakenly applied to the wrong etiology.4 For this
embolus, tension pneumothorax, and true asystole.
reason accurate and timely diagnosis of the underlying cause
is crucial. Currently the AHA recommends using physical
signs and the patient’s history to guide the management of Cardiac tamponade
PEA and asystole.2 However, physical examination can be
unreliable and many physicians may withhold therapy for a The use of ultrasound is widely accepted in the diagnosis of
fear of causing harm if uncertain of the cause of cardiac cardiac tamponade in the form of identifying a pericardial
arrest.4 effusion during the FAST screening examination for trauma.
Ultrasound is a diagnostic tool with increasing applica- Cardiac tamponade is more accurately identified by visual-
tions and use in emergency situations.5 Levitt et al. have izing pericardial effusion and right chamber collapse with
observed that emergency physicians had increased con- either of the parasternal views or the subxyphoid/costal
fidence in clinical decision-making when presented with view.14,15,18
diagnostic ultrasonographic images of medical conditions Ultrasound is also highly accurate in diagnosing this
versus clinical impression and physical examination alone. 6 condition. Mandavia et al., demonstrated that emergency
Ultrasound examination has the potential to bring increased physicians could diagnose the presence of pericardial effu-
diagnostic clarity to clinical decision-making and aid in the sion accurately when compared to a cardiologist with an
identification of a reversible cause for PEA or asystole. overall sensitivity of 96%, specificity of 98% and overall accu-
Recently many studies and case reports have examined the racy of 97.5%.18
application of emergency ultrasound to cardiac arrest.6—15 Currently the AHA recommends identifying neck vein
Niendorff et al. observed that it was feasible for trained distention and absence of pulse with CPR as diagnostic cri-
emergency sonographers to obtain diagnostic images during teria for tamponade. However these features are shared
resuscitation of cardiac arrest patients and that obtaining by tension pneumothorax as well. During cardiac arrest sit-
sonographic images did not interfere with the resuscita- uations it could be difficult to differentiate between the
tion process.15 Other investigators have also made this two conditions, as unequal breath sounds are difficult to
observation.7,14,15 Many of these investigators have studied appreciate in noisy or chaotic environments (i.e. emer-
the application of ultrasound to one, or a few, causes of PEA gency departments). Regularly using ultrasound to identify
and cardiac arrest; however a protocol that addresses the cardiac tamponade would add a greater level of accuracy
most common cardiac and pulmonary causes of PEA has not to the determination of this cause for cardiac arrest and
been developed.6—15 may prevent the use of inappropriate therapy. Therapy
There remains a need for an organized and structured for cardiac tamponade is invasive (i.e. pericardiocentesis
approach to non-arrhythmogenic cardiac arrest with suffi- or open thoracotomy). Having a test that is available in
cient diagnostic accuracy to justify appropriate aggressive real time with greater accuracy than a physical examina-
life-saving therapy. An effective protocol for emergency tion would be useful to physicians managing a patient in
ultrasound evaluation in cardiac arrest patients would cardiac arrest and reduce concerns of making a diagnos-
address the most likely and reversible causes; severe hypo- tic and therapeutic error. Physical examination and history
volemia, tension pneumothorax, cardiac tamponade, and remain important factors in medical decision-making, and
pulmonary embolus. There is a body of literature support- their importance should not be neglected. There are caveats
ing the use of ultrasound as an accurate diagnostic aid in that should always be remembered when interpreting sono-
the four above-mentioned conditions. The purpose of this graphic findings. For example patients in chronic renal
lOMoAR cPSD| 36357603
CARDIAC ARREST ULTRA-SOUND SUMMARY- A BETTER
APPROACH TO MANAGING PATIENTS IN PRIMARY NON-
ARRHYTHMOGENIC CARDIAC ARREST
KEYWORDS Summary Cardiac arrest is a condition frequently encountered by physicians in the hospital
Advanced life support setting including the Emergency Department, Intensive Care Unit and medical/surgical wards.
(ALS); This paper reviews the current literature involving the use of ultrasound in resuscitation and
Cardiac arrest; proposes an algorithmic approach for the use of ultrasound during cardiac arrest. At present
there is the need for a means of differentiating between various causes of cardiac arrest, which
Cardiac tamponade;
are not a direct result of a primary ventricular arrhythmia. Identifying the cause of pulseless
Hypovolemia;
electrical activity or asystole is important as the underlying cause is what guides management
Pulmonary embolism;
in such cases. This approach, incorporating ultrasound to manage cardiac arrest aids in the
Pulseless electrical
diagnosis of the most common and easily reversible causes of cardiac arrest not caused by
activity (PEA);
primary ventricular arrhythmia, namely; severe hypovolemia, tension pneumothorax, cardiac
Tension
tamponade, and massive pulmonary embolus. These four conditions are addressed in this paper
pneumothorax;
using four accepted emergency ultrasound applications to be performed during resuscitation of
Ultrasound
a cardiac arrest patient with the aim of determining the underlying cause of a cardiac arrest.
Identifying the underlying cause of cardiac arrest represents the one of the greatest challenges
of managing patients with asystole or PEA and accurate determination has the potential to
improve management by guiding therapeutic decisions.
We include several clinical images demonstrating examples of cardiac tamponade, massive
pulmonary embolus, and severe hypovolemia secondary to abdominal aortic aneurysm.
In conclusion, this protocol has the potential to reduce the time required to determine the
etiology of a cardiac arrest and thus decrease the time between arrest and appropriate therapy.
, lOMoAR cPSD| 36357603
C.A.U.S.E. in primary non-arrhythmogenic cardiac arrest 199
Introduction paper is twofold; first, to review the literature involving
ultrasound and resuscitative conditions. Second, to propose
Cardiac arrest is a condition frequently encountered by a goal oriented approach to the cardiac arrest patient that
physicians in the hospital setting including the Emer- incorporates the use of ultrasound to address the most com-
gency Department, Intensive Care Unit and medical/surgical mon reversible causes of non-arrhythmia cardiac arrest. The
wards. Since the implementation of preventative health name of this new test is C.A.U.S.E., an acronym for cardiac
policy and ACLS, deaths from ventricular fibrillation and arrest ultra sound examination, and whose name has the
ventricular tachycardia have decreased significantly, how- added benefit of reminding the practitioner that the pri-
ever the prevalence of pulseless electrical activity (PEA) and mary goal of their effort in PEA or asystole should be to
asystole have increased.1 Unlike ventricular fibrillation and identify and address the underlying cause. The protocol also
pulseless ventricular tachycardia where the pattern/rhythm serves to organize a process that can at times be chaotic
of electrical activity is the focus of treatment rather than and disorganized. Past studies have shown that increased
the underlying cause, PEA and asystole are corrected by organization during resuscitation increases the likelihood
addressing the underlying cause.2 The importance of identi- of survival.16,17 A similar organizational protocol has been
fying a reversible underlying cause in these forms of cardiac used for the treatment of ventricular arrhythmias using
arrest is of such importance that almost half of the ACLS three-lead electrocardiogram as a diagnostic tool with great
for experienced practitioners manual is dedicated to this success.1,2
topic and its practical application.2 Hughes et al. provided
a list of the etiologies of PEA in the order of frequency and Sonographic applications for cardiac arrest
ease of reversal.3 He lists the top five conditions as hypoxia,
hypovolemia, tension pneumothorax, pericardial tampon-
Ultrasound has been used as an effective diagnostic tool dur-
ade, and pulmonary emboli. These conditions are potentially
ing cardiac arrest and has identified causes of PEA. These
reversible, but the treatment is often invasive and may be
include cardiac tamponade, severe hypovolemia, pulmonary
deadly if mistakenly applied to the wrong etiology.4 For this
embolus, tension pneumothorax, and true asystole.
reason accurate and timely diagnosis of the underlying cause
is crucial. Currently the AHA recommends using physical
signs and the patient’s history to guide the management of Cardiac tamponade
PEA and asystole.2 However, physical examination can be
unreliable and many physicians may withhold therapy for a The use of ultrasound is widely accepted in the diagnosis of
fear of causing harm if uncertain of the cause of cardiac cardiac tamponade in the form of identifying a pericardial
arrest.4 effusion during the FAST screening examination for trauma.
Ultrasound is a diagnostic tool with increasing applica- Cardiac tamponade is more accurately identified by visual-
tions and use in emergency situations.5 Levitt et al. have izing pericardial effusion and right chamber collapse with
observed that emergency physicians had increased con- either of the parasternal views or the subxyphoid/costal
fidence in clinical decision-making when presented with view.14,15,18
diagnostic ultrasonographic images of medical conditions Ultrasound is also highly accurate in diagnosing this
versus clinical impression and physical examination alone. 6 condition. Mandavia et al., demonstrated that emergency
Ultrasound examination has the potential to bring increased physicians could diagnose the presence of pericardial effu-
diagnostic clarity to clinical decision-making and aid in the sion accurately when compared to a cardiologist with an
identification of a reversible cause for PEA or asystole. overall sensitivity of 96%, specificity of 98% and overall accu-
Recently many studies and case reports have examined the racy of 97.5%.18
application of emergency ultrasound to cardiac arrest.6—15 Currently the AHA recommends identifying neck vein
Niendorff et al. observed that it was feasible for trained distention and absence of pulse with CPR as diagnostic cri-
emergency sonographers to obtain diagnostic images during teria for tamponade. However these features are shared
resuscitation of cardiac arrest patients and that obtaining by tension pneumothorax as well. During cardiac arrest sit-
sonographic images did not interfere with the resuscita- uations it could be difficult to differentiate between the
tion process.15 Other investigators have also made this two conditions, as unequal breath sounds are difficult to
observation.7,14,15 Many of these investigators have studied appreciate in noisy or chaotic environments (i.e. emer-
the application of ultrasound to one, or a few, causes of PEA gency departments). Regularly using ultrasound to identify
and cardiac arrest; however a protocol that addresses the cardiac tamponade would add a greater level of accuracy
most common cardiac and pulmonary causes of PEA has not to the determination of this cause for cardiac arrest and
been developed.6—15 may prevent the use of inappropriate therapy. Therapy
There remains a need for an organized and structured for cardiac tamponade is invasive (i.e. pericardiocentesis
approach to non-arrhythmogenic cardiac arrest with suffi- or open thoracotomy). Having a test that is available in
cient diagnostic accuracy to justify appropriate aggressive real time with greater accuracy than a physical examina-
life-saving therapy. An effective protocol for emergency tion would be useful to physicians managing a patient in
ultrasound evaluation in cardiac arrest patients would cardiac arrest and reduce concerns of making a diagnos-
address the most likely and reversible causes; severe hypo- tic and therapeutic error. Physical examination and history
volemia, tension pneumothorax, cardiac tamponade, and remain important factors in medical decision-making, and
pulmonary embolus. There is a body of literature support- their importance should not be neglected. There are caveats
ing the use of ultrasound as an accurate diagnostic aid in that should always be remembered when interpreting sono-
the four above-mentioned conditions. The purpose of this graphic findings. For example patients in chronic renal
