This article is reprinted from =
the=20
Supplement to Circulation, July 22, 2000
Part 6:=20
Advanced Cardiovascular Life Support
Section=20
1: Introduction to ACLS 2000: Overview of Recommended
Changes=20
in ACLS From the Guidelines 2000 Conference
Evidence-Based =
International Resuscitation=20
Guidelines
At the Second =
American Heart=20
Association International Evidence Evaluation Conference and the =
international=20
Guidelines 2000 Conference on CPR and ECC, the high level of =
participation=20
of international experts changed profoundly the way all future =
resuscitation=20
guidelines will be developed. Future resuscitation guidelines cannot =
achieve=20
validity and consensus without international input. Enrichment comes =
when=20
experts from different countries=97with different systems, different =
personnel,=20
and different resources=97share their ideas, perspectives, and =
experiences. Our=20
guidelines are no longer just descriptive=97"This is how we =
do it here=94=97=20
but now can also be prescriptive=97"This=20
is how we should be doing it in the future.=94
The experts at the =
conferences reached a strong consensus to change a number of the CPR and =
ECC=20
guidelines. Large portions of the earlier guidelines remain unaltered or =
have=20
been refined on the basis of new data. Many topics, however, have been =
updated=20
to reflect consensus opinions developed according to the principles of=20
evidence-based medicine. While the evidence-based approach constrains =
the number=20
of new guidelines endorsed, it clarifies perspectives on the evidence=20
reviewed=97and on the amount of research still needed.
New Topics, =
New=20
Problems, New Guidelines
Because of rapid =
development=20
of new therapies and strategies, the sections on acute myocardial=20
infarction (MI) (now acute =
coronary=20
syndromes) and stroke have undergone major change. We have expanded =
the=20
section on special resuscitation situations for experienced =
providers. This=20
includes new topics that are known to be important causes of cardiac =
arrest but=20
that we have not addressed before, for example, cardiac arrest and =
altered vital=20
signs caused by drug overdoses and toxins, life-threatening electrolyte=20
abnormalities, near-fatal asthma, and anaphylaxis. These problems =
challenge ACLS=20
providers all over the world.
This introductory =
ACLS=20
section discusses these changes in recommendations, based on evidence =
review and=20
consensus opinion. The reasons for the class recommendations and the=20
evidence-based approach are reviewed briefly with comments from the =
Evidence=20
Evaluation Conference and the Guidelines 2000 Conference. The full =
details of=20
this intense process will be published in the Proceedings of the Guidelines 2000 =
Conference and in the journal Annals=20
of Emergency Medicine.
The new =
recommendations=20
include the following:
Pharmacology of=20
Resuscitation
=B7 Amiodarone (Class =
IIb) and=20
procainamide (Class IIb) are recommended ahead of lidocaine and =
adenosine=20
for the initial treatment of hemodynamically stable wide-complex =
tachycardia.=20
especially in patients with compromised cardiac function.
=B7 Amiodarone =
and sotalol =
(a drug that awaits =
Food and=20
Drug Administration approval for US use) are new agents recommended as =
Class IIa=20
agents for the treatment of stable=20
monomorphic and polymorphic ventricular tachycardia (VT).
=B7 References to bretylium have =
been dropped=20
from the ventricular fibrillation (VF)/pulseless VT algorithm. In 1998 =
through=20
2000, severe problems with obtaining the raw materials to produce =
bretylium=20
stopped the supply for a number of months. These guidelines must avoid=20
generating a demand that cannot be met by an undependable source. The =
world=92s=20
natural sources of bretylium appear to be nearly exhausted. Bretylium =
remains=20
acceptable to use, but it is no longer recommended. Bretylium has a high =
incidence of side effects, particularly hypotension, in the =
postresuscitation=20
setting. Bretylium stays as a Class IIb recommendation because no new,=20
supportive information is available and some studies question its=20
efficacy.
=B7 Lidocaine is an =
established agent=20
that suffered during our new emphasis on evidence. Although lidocaine =
remains=20
acceptable as an antiarrhythmic to use for the treatment of =
shock-refractory VF=20
and pulseless VT, the evidence supporting its efficacy is poor and=20
methodologically weak (levels 6, 7, and 8 only). The evidence supporting =
amiodarone is much stronger (one level I study) and justifies use of =
amiodarone=20
before lidocaine in the opinion of many. The conference experts =
concluded that=20
lidocaine could continue to be used for VF/VT but that given the =
antiquated=20
evidence, it merits only an Indeterminate class of recommendation (Class =
Indeterminate).
Lidocaine has not =
been=20
recommended for routine prophylaxis of ventricular arrhythmias in the =
setting of=20
acute MI for >8 years. Conference experts re-examined this topic and=20
concluded that the data do not justify changing the classification of =
lidocaine=20
to a Class III (evidence-of-harm)=20
agent.
=B7 Amiodarone, a respected =
and=20
effective agent in the hospital, catheterization suite, and =
critical care=20
unit, is included only in the notes for the VF/pulseless VT algorithm. =
The=20
algorithm states =93consider antiarrhythmics,=94 referring the reader to =
several=20
notes. Methodological problems in studying out-of-hospital VFIVT =
arrest=20
limit the conclusions that can be drawn about any antiarrhythmic. The =
evidence=20
supporting antiarrhythmics in general is only fair, and this accounts =
for the=20
fact that all antiarrhythmics are lumped into one Class IIb =
=93consider=94 category.=20
However, on the strength of design and execution in the ARREST study =
(Kudenchuk=20
PJ, Cobb LA, Copass MK, Cummins RO, Doherty AM, et al. N EngI J Med. =
1999;341:871=97878),=20
amiodarone does have better evidence-based support than any other=20
antiarrhythmic. The expert panel members would have no problem with =
clinicians=20
routinely using amiodarone as the first-choice antiarrhythmic for=20
shock-refractory VF/VT. This practice decision, however, must be made =
with a=20
clear awareness that the evidence=97 powerful in the design=97was weak =
in the=20
conclusions.
=B7 Magnesium has shown =
effectiveness=20
only in the treatment of known hypomagnesemic states and torsades de =
pointes,=20
for which it=20
still =
has a=20
Class IIb recommendation.
=B7 Vasopressin (arginine =
vasopressin)=20
may be a more effective pressor agent than epinephrine for promoting the =
return=20
of spontaneous circulation in cardiac arrest. The evidence from =
prospective=20
clinical trials in humans is limited but consistently positive (Class =
IIb).=20
Vasopressin (40 U IV, not repeated) may =
be=20
substituted for epinephrine as an alternative Class IIb agent. The lower =
adverse=20
effects profile may be the major indication for vasopressin.
=B7 Research on high-dose =
epinephrine=20
has not yet shown that routine use of initial and repeated or escalating =
doses=20
of epinephrine can improve survival in cardiac arrest (Class =
Indeterminate). Nor=20
has high-dose epinephrine (0.1 mg/kg) in adults been shown to improve =
survival=20
or neurological outcomes. Some troublesome evidence indicates that =
cardiac=20
arrest survivors who received high-dose epinephrine have more post =
resuscitation=20
complications than survivors who received the standard dose. Because of =
the=20
potential for harm, high-dose epinephrine (0.1 mg/kg) is not recommended =
(Class=20
Indeterminate).
Ventilation
=B7 The experts on the =
Ventilation=20
Panels recommend a reduction in the ventilation tidal volume for =
patients=20
not in cardiovascular =
collapse to=20
approximately one half of that recommended previously. Volume should =
approximate=20
6 to 7 mL/kg over 1.5 to 2 seconds (Class IIa). Higher volumes increase =
risk of=20
gastric inflation without improving blood oxygenation. For clinical =
guidance,=20
resuscitation professionals can use the =93chest rise=94 sign as a rough =
indication=20
of ventilation tidal volumes that are in the range of 6 to 7 mL/kg. =
Smaller=20
tidal volumes, however, raise the risk of inducing both hypoxia and =
hypercarbia.=20
Consequently, a widespread recommendation to provide supplemental =
oxygen.=20
adjusted on the basis of oxygen saturation readings, appears laudable, =
although=20
specific. high-level evidence to support this recommendation has not yet =
become=20
available.
=B7 Tracheal =
intubation in=20
unconscious patients should be attempted only by healthcare providers=20
experienced in performing this skill. Such persons should increase their =
experience in tracheal intubations steadily by performing intubations =
frequently=20
or by retraining regularly. Only personnel with advanced life support =
training=20
and documented skills should attempt tracheal intubation. Furthermore, =
ALS=20
providers unable to obtain regular field experience =
(non=97evidence-based=20
guideline: 6 to 12 times per year) should use alternative, non-invasive=20
techniques for airway management.
=B7 In the absence of a =
bag-mask device=20
or authorization to perform tracheal intubation, healthcare providers =
may use=20
alternative airways (laryngeal mask airway, esophageal-tracheal =
Combitube,=20
pharyngotracheal lumen airway) (Class IIb).
=B7 In the opinion of many =
experts the=20
single most important new recommendation from the Guidelines 2000 is =
long=20
overdue: emergency responders must confirm tracheal tube position =
by=20
using non-physical examination techniques. These include esophageal =
detector=20
devices, qualitative end-tidal CO2 indicators, and capnographic and =
capnometric=20
devices. In patients not in full cardiac arrest these devices are =
Class IIa.=20
In cardiac arrest and conditions of low pulmonary flow, these devices =
are=20
lowered to Class IIB because the devices may falsely indicate esophageal =
placement, leading to unnecessary removal of a properly placed =
tube.
=B7 Growing evidence suggests =
that tracheal tube=20
dislodgments after a =
successful tracheal=20
tube insertion may be occurring at much higher rates than previously =
suspected.=20
Emphasis should be placed on securing the tube carefully with a tie or =
tape.=20
With little evidence to directly support any specific commercial device, =
tracheal tube holders are a Class IIb recommendation. During long =
transport=20
efforts in the out-of-hospital setting, restless intubated patients can =
be=20
fitted with a cervical collar and immobilized with sandbags (or some =
other=20
validated technique) to prevent accidental tube dislodgment. With little =
evidence to directly support any specific commercial device, tracheal =
tube=20
holders are a Class IIb recommendation. During long transport efforts in =
the=20
out-of-hospital setting, intubated patients are at high risk for =
tracheal tube=20
dislodgment. Monitors for oxygen saturation and end-tidal CO2 =
levels=20
can detect tube dislodgments. The best technique, however, to prevent, =
detect,=20
and correct tube dislodgment is the constant vigilance of care=20
providers.
Defibrillation
=B7 Healthcare providers with =
a duty to=20
perform CPR need to be trained, equipped. and authorized to use an =
automated=20
external defibrillator (AED) (Class IIa).
=B7 Hospitals need to =
establish a=20
comprehensive program for in-hospital early CPR and early =
defibrillation.=20
Hospital staff=20
members trained in CPR need to be capable of providing early=20
defibrillation.
=B7 Hospitals need to establish =
programs to=20
achieve early defibrillation throughout the facilities and in related =
patient=20
care areas (Class I).
Public =
Access=20
Defibrillation Programs
Public access =
defibrillation=20
(PAD) programs have the potential to reduce one of the major health =
problems=97VF=20
induced cardiac arrest.
AEDs are =
recommended for=20
public sites with a high probability of at least one use every 5 years (1 arrest per =
5=20
years). Select=20
sites for AED deployment that are within a 5-minute radius of the =
majority of=20
expected arrests but outside a 5-minute radius of the closest EMS units =
(Class=20
IIb).
Acute =
Coronary=20
Syndromes
The prehospital =
12-lead=20
ECG=20
improves prehospital diagnosis, reduces hospital-based time to =
treatment,=20
identifies patients requiring reperfusion, contributes to mortality =
reduction,=20
and facilitates triage to cardiac centers with interventional =
facilities. The=20
prehospital ECG is useful and effective in prehospital urban/suburban =
EMS=20
systems and should become standard equipment on all ACLS units that =
handle acute=20
coronary syndrome patients (Class IIa).
Prehospital fibrinolytic therapy is beneficial when =
the=20
transport of patients with acute infarction from home to the hospital is =
prolonged and should be considered by busy EMS systems (Class IIa). At =
present,=20
prehospital screening of chest pain patients allows ambulance personnel =
to=20
notify hospital personnel that a person with a probable acute MI is en =
route for=20
further evaluation and care.
=97If the total =
time of the=20
following 2 intervals exceeds 60 minutes, consider prehospital =
fibrinolytics:=20
(1) onset of chest pain to contact of ACLS personnel with the patient, =
and (2)=20
arrival of ACLS personnel at the patient=92s side to arrival at the=20
hospital.
=97In Europe a =
prehospital=20
fibrinolytic program is considered whenever the above intervals exceed =
30=20
minutes. Moreover, if the Emergency Department has a door-to =
fibrinolytic=20
interval consistently >60 minutes, prehospital fibrinolytic treatment =
should=20
offer superior outcomes.
Angioplasty is an=20
alternative to fibrinolytic therapy (Class I) in =
centers with=20
high volume and experienced operators. Patients in cardiogenic shock who =
are=20
<75 years of age need transportation to cardiac interventional =
centers for=20
initiation of primary angioplasty and intra-aortic balloon =
placement.=20
Benefit occurs, however, only when door-to-balloon times average =
≤90 minutes (Class =
I).=20
Patients who are not eligible for fibrinolytic therapy because of =
increased risk=20
of intracranial bleeding need to be transported or transferred to =
these=20
centers (Class IIa). Patients with large anterior infarctions, low blood =
pressure (systolic blood pressure ≤100 mm Hg), increased heart =
rate (≥100 beats=20
per minute), or rales more than one third of the way up are also =
candidates=20
(Class IIa). Prehospital EMS systems should develop triage policies =
where=20
applicable.
=97Antiplatelet =
therapy with=20
glycoprotein IIb/IIIa inhibitors for patients with non-Q-wave MI and =
high-risk=20
unstable angina provides clinically significant benefit (Class IIa).=20
Antithrombin therapy with low-molecular-weight heparins is now an =
alternative to=20
unfractionated heparin in high-risk unstable angina/non-Q-wave MI =
patients. Data=20
for this class of agents, however, is heterogeneous, in part because of =
variable=20
anti-factor Xa inhibition (Class Indeterminate). The dose of =
unfractionated=20
heparin, when used as adjunctive therapy with fibrin-specific lytics =
(alteplase,=20
reteplase) is now reduced to a bolus of 60 U/kg (maximum 4000 U) and an =
infusion=20
of 12 IU/kg per hour. This dose reduction will help to minimize the =
incidence of=20
intracerebral hemorrhage.
=97Metabolic =
manipulation of=20
the infarct with glucose-potassium-insulin is under continuing =
investigation.=20
This therapy is acceptable and of some benefit for diabetic patients and =
patients undergoing reperfusion (Class IIb).
=97All patients =
with acute MI,=20
including non-Q-wave MI, need aspirin and (3-blockers in the absence of=20
contraindications (Class I). Patients with a large anterior =
infarction,=20
left ventricular dysfunction, and ejection fraction <40% need early=20
angiotensin-converting enzyme inhibition in the absence of=20
hypotension.
Stroke
=B7 Intravenous =
recombinant tissue=20
plasminogen activator (rtPA) improves neurological outcome when =
administered=20
within 3 hours of stroke onset in patients who meet=20
fibrinolytic criteria (Class I). Patients with stroke presenting within =
3 hours=20
require emergent triage. The urgency should equal that of an acute MI, =
with=20
ST-segment elevation.
=B7 The use of rtPA =
in patients with =
symptom=20
onset between 3 and 6 hours of presentation at an Emergency Department =
is under=20
investigation. While subgroups of such patients may benefit from =
fibrinolytic=20
treatment, routine use is not currently recommended (Class=20
Indeterminate).
=B7 Prourokinase has been =
found to=20
improve neurological outcome in patients treated within 3 to 6 hours in =
one=20
completed but unpublished study. Review of the published data and =
additional=20
studies are needed before this fibrinolytic agent can be recommended =
(Class=20
Indeterminate).
=B7 EMS systems should implement a=20
prehospital stroke protocol to rapidly identify patients who may =
benefit=20
from fibrinolytic therapy. This approach is similar to the protocol for =
chest=20
pain patients (Class IIb). Transport patients who may be candidates for=20
fibrinolytic therapy to hospitals identified as acute stroke treatment=20
facilities with 24-hour availability of computerized tomography and=20
interpretation (Class IIb).
Postresuscitation=20
Care
=B7 Following cardiac arrest, do =
not actively=20
rewarm patients who are mildly hypothermic (Class IIb). Active =
initiation of=20
hypothermia after cardiac arrest is under clinical investigation (Class=20
Indeterminate). Treat febrile patients to achieve normothermia, a goal =
of early=20
therapy (Class IIa).
=B7 Following cardiac arrest, =
ventilatory=20
values in patients who require mechanical ventilation should be =
maintained=20
within the normal range (Class IIa). Hyperventilation may be harmful and =
should=20
be avoided (Class III). An exception is the use of hyperventilation in =
patients=20
who have signs of cerebral herniation after resuscitation.
Toxicology
=B7 Cocaine use is associated with =
serious=20
ventricular arrhythmias and acute coronary syndromes. The use of=20
(β-blockers in patients with cocaine-associated acute coronary =
syndromes has=20
caused coronary vasoconstriction and should be avoided (Class III). =
Nitrates=20
should be first-line therapy (Class I) together with benzodiazepines =
(Class=20
IIa). α-Adrenergic blocking agents may induce tachycardia and =
hypotension and=20
should be reserved for patients who do not respond to nitrates and=20
benzodiazepines (Class IIb).
=B7 Hypotension or ventricular =
arrhythmias=20
occur with tricyclic overdose. The induction of systemic alkalosis (pH =
of 7.50=20
to 7.55) is the treatment of choice =
(Class=20
IIa). Antiarrhythmic agents such as lidocaine or procainamide have not =
been=20
studied in this setting (Class Indeterminate).
=B7 Acute respiratory failure =
(respiratory=20
acidosis and hypoxemia) may occur with opiate overdose. Reverse these=20
abnormalities by mechanical ventilation before the administration of =
naloxone.=20
This will reduce the incidence of pulmonary edema and serious =
arrhythmias=20
associated with abrupt catecholamine elevation (Class IIa).
Overview of =
ACLS
ACLS includes the =
knowledge=20
and skills necessary to provide the appropriate early treatment for=20
cardiopulmonary arrest. Additional important areas include the proper =
management=20
of situations likely to lead to cardiac arrest and stabilization of the =
patient=20
in the early period following successful resuscitation. ACLS includes =
(1) basic=20
life support: (2) use of advanced equipment and special techniques for=20
establishing and maintaining effective ventilation and circulation: (3) =
ECG=20
monitoring, 12-lead ECG interpretation, and arrhythmia recognition; (4)=20
establishment and maintenance of intravenous access; (5) therapies for =
the=20
treatment of patients with cardiac or respiratory arrest (including=20
stabilization in the post arrest phase); (6) treatment of patients with=20
suspected acute coronary syndromes, including acute MI; and (7) =
strategies for=20
rapid assessment and treatment with tPA of eligible stroke patients. =
ACLS=20
includes the knowledge, training, and judgment required to use these =
skills and=20
the ability to perform them.
Communities should =
provide=20
rapid and effective ACLS. Every community should strive continually to =
implement=20
the Chain of Survival and provide as many high-quality ACLS components =
as=20
possible, in particular very early defibrillation using AEDs (see =
=93Part 4: The=20
Automated External Defibrillator: Key Link in the Chain of Survival=94) =
and=20
non-invasive airway support.
BLS and ACLS =
should be=20
integrated into a community as part of an EMS system. This system should =
have=20
sufficient laypersons trained in BLS to ensure immediate ventilatory and =
circulatory assistance to any cardiac arrest victim within 5 minutes and immediate entry =
of that=20
victim into the EMS system. We strongly encourage implementation of =
public=20
access defibrillation in high-risk settings. In turn the emergency care =
system,=20
under medical supervision, should provide rescue personnel adequately =
trained in=20
BLS and ACLS to respond promptly when summoned. ACLS must be continued =
either=20
until the patient has been admitted to a medical facility capable of =
continuing=20
care or until life support efforts have been terminated by order of the=20
responsible physician or by a properly executed advance =
directive.
The same level of =
training,=20
commitment, and medical supervision should be applied to in-hospital =
ACLS. In=20
particular, prompt BLS and rapid defibrillation should be available in =
all areas=20
of a healthcare facility (Class IIa).
BLS and =
Early=20
Defibrillation
For people in =
cardiac=20
arrest, rapid defibrillation in =
<5=20
minutes is a high-priority goal. Community and in-hospital ACLS must =
be=20
supported by a well-established BLS program that can provide immediate =
emergency=20
CPR. The Evidence Evaluation Conference and Guidelines 2000 Conference =
again=20
affirmed and endorsed the principle of early defibrillation from =
1991 =97 the=20
recommendation that healthcare providers with a duty to respond to =
cardiac=20
arrest should be educated, equipped. and authorized to perform automated =
external defibrillation (Class IIa). The ideal response time is achieved =
when=20
people collapse in front of a person who has an AED. Such cases occur in =
many=20
locations, and in general the survival rate can be 70% to =
80%.
For respiratory =
arrest,=20
airway adjuncts and ventilation devices should be readily available. In =
cardiac=20
arrest, the need for early defibrillation is clear and should have the =
highest=20
priority. Today, with the availability of AEDs, defibrillation is =
considered=20
part of BLS. Adjunctive equipment should not divert attention or effort =
from=20
basic resuscitative measures. Rescue personnel should know the =
indications for=20
and techniques of using adjunctive equipment. Such equipment should be =
tested=20
periodically according to prescribed regulations and each periodic test=20
documented.
Circulation. =
2000; 102(suppl=20
I):I-86-I-89.
=A9 2000 American =
Heart=20
Association. Inc.
Circulation=20
is=20
available at http://www.circulationaha.org/=20