Best Practice:
ACLS: Physiology and Review of
Current Literature
Jacob Imber, MD
Wednesday, Aug 12, 2015
Objectives
• Describe the epidemiology of cardiac arrest
• Review 3-phase cardiac arrest theory
– Discuss impact on resuscitation efforts
• Discuss physiologic goals of CPR
– Review evidence to support current guidelines
• Examine use of IV medications in CPR
Motivation
• Cardiac arrest is becoming less frequent
(importance of practice and review)
– Decreasing incidence of CAD
– Increased recognition of unstable patients
– Rapid response teams
• CPR remains the mainstay of resuscitation
• Poor performance of floor staff prior to arrival
of emergency team (next slide)
• Poor resident confidence in code situations
identified on UNMH exit interviews and
surveys
Department Staff Performance
Einav et al. “Performance of department staff in the window between discovery of collapse to cardiac arrest team arriaval” Resuscitation
(2006) 69, 213-220
Denominator
The percent of events in which the
specified recommendation was not
followed (n = 244)
Assess pulsea
All
19.3% (47/244)
Attach monitor/defibrillator when
availableb
Patients not previously connected to an
electrocardiogram
34% (35/103)c
Assess rhythmb
All
33.6% (82/244)
Recommendation
Basic diagnostic measures
Patients connected to an
50% (28/56)
electrocardiogram by department teams
Patients who were already monitored
by electrocardiography prior to the
event
7.9% (11/140)
Patients with agonal breathing
43.5% (50/115)
Patients in full respiratory arrest
17.3% (13/75)
If no pulse-start chest compressionsb
Patients diagnosed as pulseless
12.5% (13/104)
Attempt defibrillationb
Patients diagnosed with VF/pulseless VT 44% (15/34)
Therapeutic Measures
Basic
Provide positive pressure ventilations
(bag-mask)b
Get With The Guidelines
(GWTG)-Resuscitation
• formerly National Registry of Cardiopulmonary
Resuscitation (NRCPR)
• AHA-sponsored, prospective, multisite, observational
study of in-hospital resuscitation
• all adult (≥18 years of age) and pediatric (<18 years
of age) patients, visitors, employees, and staff within
a facility (including ambulatory care areas) who
experience a resuscitation event
Peberdy MA, et al. Cardiopulmonary resuscitation of adults in the hospital: a report of 14720 cardiac arrests from the
National Registry of Cardiopulmonary Resuscitation. Resuscitation. 2003 Sep;58(3):297-308. PMID: 12969608.
Epidemiology
• 3rd leading cause of US deaths (1-cancer, 2-CAD)
• Table below from Get with the Guidelines data
Out-of-Hospital Cardiac Arrest
Statistical
Update
In-Hospital Cardiac Arrest
Incidence
Bystander
CPR
(overall)
Survivor
rate*
(overall)
Survival rate*
Incidence
2013
359,400
40.1%
9.5%
2012
382,800
41.0%
11.4%
Adults
Children
209,000
23.9%
40.2%
209,000
23.1%
35.0%
IOM (Institute of Medicine). 2015. Strategies to improve cardiac arrest survival: A time to act. Washington, DC: The
National Academies Press. p. 249.
Outcomes
• Return of Spontaneous Circulation (ROSC)
– “restoration of a spontaneous perfusing rhythm
that results in more than an occasional gasp,
fleeting palpated pulse, or arterial waveform”
• Survival to discharge
• Neurologic outcome/Return to prior level of
functioning
Cardiac Arrest and Cardiopulmonary Resuscitation Outcome Reports: Update and Simplification of the Utstein Templates for
Resuscitation Registries: A Statement for Healthcare Professionals From a Task Force of the International Liaison Committee on
Resuscitation. Jacobs I, et al. Circulation. 2004; 110: 3385-3397
Cerebral Performance Category
(CPC) Scale
CPC 1. Good cerebral performance: Conscious, alert, able to work and lead a normal life. May
have minor psychologic or neurologic deficits (mild dysphasia, non-incapacitating hemiparesis, or
minor cranial nerve abnormalities)
CPC 2. Moderate cerebral disability: Conscious. Sufficient cerebral function for part-time work in
sheltered environment or independent activities of daily life (dress, travel by public
transportation, food preparation). May have hemiplegia, seizures, ataxia, dysarthria, or
permanent memory or mental changes.
CPC 3. Severe cerebral disability: Conscious. Dependent on others for daily support (in an
institution or at home with exceptional family effort). Has at least limited cognition. This category
includes a wide range of cerebral abnormalities, from patients who are ambulatory but have
severe memory disturbances or dementia precluding independent existence, to those who are
paralyzed and can communicate only with their eyes, as in the “locked in” syndrome.
CPC 4. Coma or vegetative state: any degree of coma without the presence of all brain death
criteria. Unawareness, even if appears awake (vegetative state) without interaction with
environment; may have spontaneous eye opening and sleep/awake cycles. Cerebral
unresponsiveness.
CPC 5. Brain death: apnea, areflexia, EEG silence, etc. circulation preserved.
Safar P. Resuscitation after Brain Ischemia, in Grenvik A and Safar P Eds: Brain Failure and Resuscitation, Churchill
Livingstone, New York, 1981; 155-184.
All Codes are not created equal
• Survival and Outcomes are directly affected by
a number of variables
– Presenting rhythm
– Patient demographics (age, race)
– Location of cardiac arrest
– Pre-existing co-morbidities
– Knowledge of emergency respondents
Survival for IHCA improving
Chan PS. Public health burden of in-hospital cardiac arrest. Paper commissioned by the Committee on the Treatment of
Cardiac Arrest: Current Status and Future Directions. 2015. http://www.iom.edu/~/media/Files/
Report%20Files/2015/GWTG.pdf (accessed June 30, 2015).
It’s good to be male and 50
Racial disparities
Don’t code at night
Chan PS. Public health burden of inhospital cardiac arrest. Paper
commissioned by the Committee on the
Treatment of Cardiac Arrest: Current
Status and Future Directions. 2015.
http://www.iom.edu/~/media/Files/
Report%20Files/2015/GWTG.pdf
(accessed June 30, 2015).
Peberdy MA, et al, ; for the
National Registry of
Cardiopulmonary Resuscitation
Investigators. Survival From InHospital Cardiac Arrest During
Nights and Weekends. JAMA.
2008;299(7):785-792.
doi:10.1001/jama.299.7.785.
IOM (Institute of Medicine). 2015. Strategies to improve cardiac arrest survival: A time to act. Washington, DC: The
National Academies Press. p. 251.
Nadkarni VN, et al; for the National Registry of Cardiopulmonary Resuscitation Investigators. First Documented Rhythm
and Clinical Outcome From In-Hospital Cardiac Arrest Among Children and Adults. JAMA. 2006;295(1):50-57.
doi:10.1001/jama.295.1.50.
With all these variables, what do
you say to a patient?
• Rough Estimates:
– ROSC: 40-60%
– Survival to discharge: 15-30%
– Good neurologic outcome: 2-5%
• Go-Far scoring system for “likelihood of good
outcome in resuscitation”
Ebell MH, Jang W, Shen Y, Geocadin RG. Development and Validation of the Good Outcome Following Attempted
Resuscitation (GO-FAR) Score to Predict Neurologically Intact Survival After In-Hospital Cardiopulmonary Resuscitation.
JAMA Intern Med. 2013 Sep 9.
Cardiac arrest
Definition
Sudden cessation of heartbeat and cardiac
function resulting in the loss of effective
circulation.
But is it that simple?
3-Phase, Time-Sensitive Model of
Cardiac Arrest
• Electrical Phase (0-4mins)
– Primary problem is disorganized electricity
– Shock should be first intervention if possible
– Supported by efficacy of ICD (shock 15-20secs into rhythm,
rarely fails to restore perfusing rhythm)
• Circulatory Phase (4-10mins)
– Primary problem is lack of blood/O2 flow to heart
– Chest compressions/ventilation should be initiated first,
initial defib should occur after 1st cycle of CPR (2min after
initiation of code)
Weisfeldt ML, Becker LB. Resuscitation After Cardiac Arrest A 3-Phase Time-Sensitive Model. JAMA.
2002;288(23):3035-3038. doi:10.1001/jama.288.23.3035.
Evidence?
• Yakaitis et al. (1980) Dog models with VF arrest, initial defib 1,
3, 5, 9min
– Initial Defib is optimal in 1/3min groups
5min group
Immediate defib
CPR 1min, 1mg Epi then Defib
Successful Shock
30% (3/10)
70% (7/10)
ROSC
0% (0/10)
40% (4/10)
• Niemann et al. (2000) showed after 7.5min untreated VF,
5min of CPR + epi vs. immediate defib was 64% (9/14) vs. 21%
(3/14) chance of ROSC
• Niemann also showed no change in outcome for CPR + defib
vs. immediate defib in <5min of untreated VF
Yakaitis et al. Influence of time and therapy on ventricular defibrillation in dogs. Crit Care Med 1980;8 157-163
Niemann et. Al. Immediate countershock vs. CPR before countershock in a 5-min swine model of VF arrest. Ann Emerg Med. 2000;36:543-546
Metabolic Phase (10+ mins)
• Theorized because many studies show dramatic decrease in
efficacy for CPR and Defib when cardiac arrest has occurred
for >10min prior to initiation
• Irreversible injury from ischemia vs. toxic metabolites
• Gut mucosal translocation resulting in cytokine release?
• Peripheral vasoconstrictors cause organ ischemia?
• Increased risk of reperfusion injury?
• Forms basis of “therapeutic hypothermia” theory
• No change in basic CPR recommendations, though there is
some consideration for changes in post-arrest care under
presumption of worsened tissue injury etc. (i.e. hypothermia)
Evidence for Three-Phase Model in humans
Gilmore CM, et al. Three-Phase Model of
Cardiac Arrest: Time-Dependent Benefit of
Bystander Cardiopulmonary Resuscitation.
Am J Cardiol 2006;98:497– 499
Guideline development process
American Heart Association. Highlights of the 2010 American Heart Association Guidelines for CPR and ECC.
Major Challenges to Delivering
High-Quality ACLS
AHA evaluation of ACLS found:
• Poor quality: inconsistent rate or inadequate
depth and lack of fidelity to ACLS cycle
• Harmful interruptions
• Inadequate cerebral and cardiac perfusion
• Inadequate support for defibrillation
Performance in CPR?
• Abella examined University of Chicago
Hospitals and found:
– Chest compression rate was too slow
– Chest compression depth was too shallow
– Ventilation rate was too high
– Time without compressions was too frequent and
too prolonged
(Abella, B.S. et al. Quality of cardiopulmonary resuscitation during in-hospital cardiac
arrest. JAMA 2005;293:305-310)
Coronary Blood Supply
Fed by backfill pressure called
Coronary Perfusion
Pressure
Diastolic Aortic Pressure –
Right Atrial Diastolic Pressure
Calculated to require 15mmHg
CPP for ROSC
CPP vs. ROSC
Paradis NA et al. JAMA 1990 Feb 23;263(8): 1106-13
Establishing Coronary Perfusion
Pressure with Chest Compressions
Impact of CC interruption on CPP
How important are pauses in chest compressions prior to
defibrillation? (Cheskes et al. 2011)
Circulation. 2011 Jul 5;124(1):58-66. doi: 10.1161/CIRCULATIONAHA.110.010736. Epub 2011 Jun 20
• 815 patients with out of hospital cardiac arrest (OHCA)
• Pre-shock chest compression pause ≥ 20 seconds had OR
0.47 for survival vs pauses < 10 seconds
• Pre-shock chest compression pause ≥ 40 seconds had OR
0.54 for survival vs pauses < 20 seconds
• Second study by Tang et al. noted that after CPP was
established, ~60 seconds were required to recover CPP for 10
second interruption
Tang et al. “Adverse effects of interrupting precordial compression during cardiopulmonary resuscitation” Crit Care Med 1997; 25:733-736
High-Quality Chest Compressions
• Uninterrupted
High-Quality Chest Compressions
• Uninterrupted
• Rate of 100
Rate compared to Likelihood of
ROSC
Abella et al. “Chest compression rates during cardiopulmonary resuscitation are suboptimal” Circulation. 2005 Feb 1;111(4):428-34
Rate of CC divided into 30 second
intervals
1626 30-sec intervals
Rate between 90-110 ~37% of the intervals
(Abella BS et al., Circulation 2005;111;428-434)
High-Quality Chest Compressions
• Uninterrupted
• Rate of 100
• Depth of 5cm (2in)
Likelihood of Successful Defibrillation as
compared to CC depth
(Edelson DP et al., Resuscitation 2006;71;137-145)
High Variation of Depth During CPR
<50% of 30 second intervals were 38-51mm
(Abella BS, Proceedings of ERC Symposia: Squeezing High Performance Out of
CPR Medcom 2006)
High-Quality Chest Compressions
•
•
•
•
•
Uninterrupted
Rate of 100
Depth of 5cm (2in)
Recoil
Location (center of chest, lower 1/3)
Hand position
Appropriate Ventilation
• Synchronous ventilation (OHCA)
– 30:2 in CPR cycle
• Asynchronous ventilation (IHCA)
– 6-10 breaths per minute (wait 6-10 seconds
between each breath)
• Increased air and pressure within the lungs
increases impedance to blood flow
Why limit ventilations? Isn’t more better?
Ordelman et al. Circulation 2013; 128:A290
Impact of Ventilatory Rate on
Survival
Aufderheide TP et al. “Hyperventilation-induced hypotension during
cardiopulmonary resuscitation” Circulation 2004
Average Ventilatory Rates
• Aufderheide et al. demonstrated that in outof-hospital rescues the frequency of
ventilation averaged 30 times per minute
Aufderheide et al. “Hyperventilation-induced hypotension during cardiopulmonary resuscitation”. Circulation. 2004 Apr 27;109(16):1960-5.
Epub 2004 Apr 5
• Abella showed a similar effect for in-hospital
rescues, noting ventilation rates greater than
20 times per minute in 60.9% of the CPR
segments measured.
Dr. Claude Beck’s
st
1
defibrillator
Cooper JA, Cooper JD, Cooper JM. Cardiopulmonary Resuscitation: History, Current Practice, and Future Direction.
Circulation. 2006;114:2839-2849.
Relation of collapse to CPR and
defibrillation to survival
Graphical representation of simplified
(includes collapse to CPR and collapse to
defibrillation only) predictive model of survival
after witnessed, out-of-hospital cardiac arrest
due to VF. Each curve represents change in
probability of survival as delay (minutes) to
defibrillation increases for a given collapse-toCPR interval (minutes).
For every minute of delay
from collapse to CPR or
defibrillation, death is 1.1
times more likely.
Valenzuela TD et al. Estimating effectiveness of cardiac arrest interventions: a logistic
regression survival model. Circulation. 1997 Nov 18;96(10):3308-13.
Shorter pauses before defibrillation
better
Edelson DP et al. Effects of compression depth and pre-shock pauses predict defibrillation failure during
cardiac arrest. Resuscitation. 2006 Nov;71(2):137-45. Epub 2006 Sep 18.
Delayed defibrillation is associated with lower
rates of survival after in-hospital cardiac arrest
Chan PS et al. Delayed time to defibrillation after in-hospital cardiac arrest. NEJM. 2008 Jan
3;358(1):9-17. doi: 10.1056/NEJMoa0706467.
What about the drugs?
Olasveengen TM et al, Intravenous drug administration during out-of-hospital cardiac arrest: a randomized trial.
JAMA. 2009 Nov 25;302(20):2222-9. doi: 10.1001/jama.2009.1729.
Is that really true? Really?
Donnino et al. BMJ 2014;348:g3028
There must be other studies
• Meta-Analysis on OHCA performed for
Resuscitation in 2014 by Lin et al.
– Epinephrine gives increased rate of survival to
admission and ROSC
– No change in survival to discharge or neurologic
outcome
– Addition of vasopressin did not change outcome
Lin et al. “Adrenaline for out of hospital cardiac arrest resuscitation” Resuscitation 84 (2014) 732-740
What about a more recent study?
Dumas et al. “Is epinephrine during cardiac arrest associated with worse outcomes in resuscitated patients? JACC 64;22 (2014)
Association Between Outcome and Early Dose of EPI and According to the Initial Rhythm
The odds ratios were adjusted according to baseline characteristics (age, sex, hypertension, diabetes mellitus, smoking, witnessed status, bystander
cardiopulmonary resuscitation, length of resuscitation), and hospital covariates (PCI, hypothermia, post–cardiac arrest shock, blood lactate level).
So? What to do?
• Epinephrine remains a part of the algorithm
and plays a role in immediate peri-code
survival
• It remains to be seen if timing of epinephrine
is the key element (remember the 3-phase
model?)
• Continue to use, but emphasis should be
placed on chest compressions and
defibrillation
Summary
• Cardiac arrest remains a catastrophic event
with poor outcomes
– We are beginning to be able to anticipate who is
likely to have a worse outcome, but this remains
challenging
• Resuscitation is likely a time-dependent
activity with different interventions (shock vs.
meds/CC) being indicated based on time from
arrest
Summary (Cont’d)
• Chest Compressions and defibrillation are the
mainstay of resuscitation
– Success of CPR is dependent on high-quality
compressions and ventilation
– Avoidance of interruption when providing defib is
vital to outcomes
• We have room to improve on our
performance in resuscitation as a profession
• Medications in ACLS remain useful, but their
role is secondary to the above interventions
Questions?