Author(s): Julie Considine & Carl McQueen
Date: 31 December 2014
Question: CPR beginning with compressions first (30:2) compared to CPR beginning with ventilation first (2:30) for adults and children who are in cardiac arrest in any setting
Settings: Any settings
Bibliography (systematic reviews):
1. Sekiguchi H, Kondo Y, Kukita I. Verification of changes in the time taken to initiate chest compressions according to modified basic life support guidelines. American Journal of Emergency Medicine. 2013. 31: 1248-1250
2. Marsch, S., Tschan, F., Semmer, N. K. et al. ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulator-based trial. Swiss Medical Weekly, 2013. 143, w13856.
3. Lubrano, RC, Cecchetti E, Bellelli I et al. Comparison of times of intervention during pediatric CPR maneuvers using ABC and CAB sequences: A randomized trial. Resuscitation 2012. 83:1473-1477.
4. **Kobayashi M, Fujiwara A, Morita H et al. A manikin-based observational study on cardiopulmonary resuscitation skills at the Osaka Senri medical rally. Resuscitation.2008. 78: 333-339.
** papers that were included in 2010 worksheet
Papers included in 2010 worksheet but exlcuded from this worksheet
Review, opinion or discussion papers
Handley AJ, Koster R. Monsieurs K, Perkins GD, Davies S, Bossaert L. European Resuscitation Council Guidelines for Resuscitation 2005. Section 2. Adult basic life support and use of automated external defibrillators. Resuscitation 2005;67S1: S7-S23.
European basic life support guidelines.
Meursing BTJ, Wulterkens DW, van Kesteren RG. The ABC of resuscitation and the Dutch (re)treat. Resuscitation 2005; 64: 279-286.
Nolan J. Basic life support. Current opinion in anaesthesiology 2008; 21: 194-199.
Mathematical modeling papers
Babbs CF, Kern KB. Optimum compression to ventilation ratios in CPR under realistic, practical conditions: a physiological and mathematical analysis. Resuscitation. 2002 Aug;54(2):147-57.
Not relevant to PICO
Brenner B, E. , Van D, C. , Cheng D, Lazar E, J. . Determinants of reluctance to perform CPR among residents and applicants: The impact of experience on helping behavior. Resuscitation. 1997;35(3):203-11.
Handley A, J. Four-step CPR - improving skill retention. Resuscitation. 1998;36(1):3-8.
Nolan JP, Soar J, Baskett P, J. F. . The 2005 compression–ventilation ratio in practice: Cycles or time? Resuscitation. 2006;71(1):112-4.
Odegaard S, Saether E, Steen PA, Wik L. Quality of lay person CPR performance with compression:ventilation ratios 15:2, 30:2 or continuous chest compressions without ventilations on manikins. Resuscitation. 2006;71(3):335-40.
Odegaard S, Pillgram M, Berg NEV, Olasveengen T, Kramer-Johansen J. Time used for ventilation in two-rescuer CPR with a bag-valve-mask device during out-of-hospital cardiac arrest. Resuscitation. 2008;77(1):57-62.
Quality assessment
№ of studies
Study design
Risk of bias
Inconsistency
№ of patients
Indirectness
Imprecision
Other considerations
CAB: CPR beginning
with compressions first
(30:2)
ABC: CPR
beginning with
ventilation first
(2:30)
Effect
Relative
(95% CI)
Absolute
(95% CI)
Quality
Importance
Time to commencement of chest compressions - RCTs (assessed with: seconds)
1
randomised trials
serious
345
not serious
serious
1
not serious
none
Lubrano [2012 p1473]
Randomized manikin study comparing CAB
(I) (n=155 2-person teams) with ABC (C)
(n=152 2-person teams). Time to
commencement of chest compressions in
CARDIAC ARREST: 19.27±2.64 vs 43.40 ±
5.05 (p<0.05). 95% CI -23.58 to -24.82,
difference 24.13 seconds in favour of CAB
-
0 higher
(0 higher to 0
higher)
⨁◯◯◯
VERY LOW
IMPORTANT
serious
1
not serious
none
Sekiguchi [2013 p1248]
Observational manikin study comparing
2010-BLS (CAB) with 2005-BLS (ABC. n=40
healthcare providers performed both CAB &
ABC. Time to commencement of chest
compressions: 15.4 ± 3.0 vs 36.0 ± 4.1
(p<0.001). Mean difference 20.6 seconds in
favour of CAB.
-
0 higher
(0 higher to 0
higher)
⨁◯◯◯
VERY LOW
IMPORTANT
Time to commencement of chest compressions - non RCTs (assessed with: seconds)
2
observational
studies
serious
23
not serious
Kobayash 2008, p333)
Observational manikin study of resuscitation
quality evaluated in n=33 teams participating
in medical rallies (2006, 2007). Compared
ACB (ERC method) vs ABC (AHA method).
Median time to commencement of chest
compressions: 16 (IQR=14-26) vs 442
(IQR=41.5-59), p<0.001) Median difference
26 seconds in favour of CAB.
Time to commencement of rescue breaths - RCTs (assessed with: seconds)
2
randomised trials
serious
not serious
345
serious
1
not serious
none
Lubrano [2012 p1473] Randomized manikin
study comparing CAB (I) (n=155 2-person
teams) with ABC (C) (n=152 2-person
teams). Time to commencement of
ventilation in RESPIRATORY ARREST:
19.13 ± 1.47 vs 22.66 ± 3.07 (p<0.05). 95%
CI −3.00 to −3.86, difference 3.53 seconds in
favour of CAB. Time to commencement of
rescue breaths in CARDIAC ARREST:
28.40±3.07 vs 22.66 ± 3.07 (p<0.05). 95%
CI 5.76 to 6.15, difference 5.74 seconds in
favour of ABC
-
0 higher
(0 higher to 0
higher)
⨁◯◯◯
VERY LOW
IMPORTANT
-
0 higher
(0 higher to 0
higher)
⨁⨁◯◯
LOW
IMPORTANT
-
0 higher
(0 higher to 0
higher)
⨁◯◯◯
VERY LOW
IMPORTANT
Marsch [2013 p w13856] Randomised
manikin study comparing CAB (C) (n=55
teams) with ABC (n=53 teams). Time to
commencement of rescue breaths: 3 ±2 vs 6
± 8 vs, p=0.03). Mean difference 5 seconds
in favour of CAB.
Time to completion of first CPR cycle - RCT (assessed with: seconds)
1
randomised trials
not serious
3
not serious
serious
1
not serious
none
Marsch [2013 p w13856] Randomised
manikin study comparing CAB (C) (n=55
teams) with ABC (n=53 teams). Time to
completion of first CPR cycle (30 CC & 2 V):
48 ±10 vs 63±17, p<0.001). Mean difference
15 seconds in favour of CAB.
Time to diagnosis of need for resuscitation (unresponsive, respiratory arrest, cardiac arrest) - RCT (assessed with: seconds)
1
randomised trials
serious
345
not serious
serious
1
not serious
MD – mean difference, RR – relative risk
1.
Mannikin study (all studies)
2.
Non-randomised study (Sekiguchi 2013 p1248; Kobayash 2008, p333)
3.
Unblinded study (all studies)
4.
Randomisation method not detailed (Marsch 2013 p w13856; Lubrano 2012 p1473)
5.
Lubrano - teams 'failed' test if one or both instructors identified a mistake classed as 'serious' (Lubrano 2012 p1473)
none
Lubrano [2012 p1473] Randomized manikin
study comparing CAB (I) (n=155 2-person
teams) with ABC (C) (n=152 2-person
teams). Time to evaluation of response: 3.26
±0.63 vs 3.2 ±0.73, p=NS). No difference.
Time to diagnosis of RESPIRATORY
ARREST: 17.48 ±2.19 vs 19.17±2.38,
p<0.05). 95% CI -1.37 to -2.08, difference
1.69 seconds in favour of CAB. Time to
diagnosis of CARDIAC ARREST: 17.48
±2.19 vs 41.67±4.95, p<0.05). 95% CI 23.65 to -24.84, difference 24.19 seconds in
favour of CAB
Criteria
Problem
Is there a problem
priority?
Judgements
○ No
○ Probably no
○ Uncertain
○ Probably yes
● Yes
○ Varies
There is ongoing debate in the scientific literature regarding the merits of commencing
resuscitation with chest compressions prior to ventilations. Internationally, most adult BLS
guidelines commence chest compressions prior to ventilations however there is variability in
paediatrics with different approaches in various jurisdictions. 1-4
○ No included
The relative importance or values of the main outcomes of interest:
studies
What is the overall
certainty of this
evidence?
○ Very low
● Low
○ Moderate
○ High
● Important
Benefits &
harms of
the options
uncertainty or
variability
○ Possibly
Is there important
uncertainty about
how much people
value the main
outcomes?
Additional
considerations
Research evidence
important
uncertainty or
variability
○ Probably no
important
uncertainty of
variability
○ No important
uncertainty of
variability
Outcome
Relative
importance
Certainty of the
evidence (GRADE)
Time to commencement of chest compressions RCTs
IMPORTANT
⨁◯◯◯
Time to commencement of chest compressions non RCTs
IMPORTANT
⨁◯◯◯
Time to commencement of rescue breaths - RCTs
IMPORTANT
⨁◯◯◯
Time to completion of first CPR cycle - RCT
IMPORTANT
⨁⨁◯◯
Time to diagnosis of need for resuscitation
(unresponsive, respiratory arrest, cardiac arrest) - IMPORTANT
RCT
VERY LOW
VERY LOW
VERY LOW
LOW
⨁◯◯◯
VERY LOW
Criteria
Judgements
○ No known
Summary of findings: CPR beginning with ventilation first (2:30)
undesirable
Outcome
Are the desirable
anticipated effects
large?
Are the undesirable
anticipated effects
small?
Are the desirable
effects large
relative to
undesirable effects?
○ No
● Probably no
○ Uncertain
○ Probably yes
○ Yes
○ Varies
○ No
○ Probably no
○ Uncertain
● Probably yes
○ Yes
○ Varies
○ No
● Probably no
○ Uncertain
○ Probably yes
○ Yes
○ Varies
Additional
considerations
Research evidence
Time to
commencement of
chest compressions RCTs
Time to
commencement of
chest compressions non RCTs
Time to
commencement of
rescue breaths - RCTs
Time to completion of
first CPR cycle - RCT
Time to diagnosis of
need for resuscitation
(unresponsive,
respiratory arrest,
cardiac arrest) - RCT
Without CPR
beginning with
compressions
first (30:2)
With CPR
beginning with
compressions
first (30:2)
Difference
(95% CI)
Relative
effect
(RR)
(95% CI)
-
Criteria
Are the resources
required small?
Resource
use
Is the incremental
cost small relative
to the net benefits?
Judgements
○ No
● Probably no
○ Uncertain
○ Probably yes
○ Yes
○ Varies
In many jurisdictions, CAB is already in place in adult BLS so resource requirements are small. In
jurisdictions where ABC is used, there are a number of resources required to implement CAB in
preference to ABC including investments required to train rescuers, reconfiguration of CPR feedback
devices and AEDs, and production of educational materials.
○ No
○ Probably no
● Uncertain
○ Probably yes
○ Yes
○ Varies
As there are no human studies of CAB vs ABC, the net benefits are unknown. The very low quality of
evidence from manikin studies presented in this worksheet suggests that CAB decreases the time to
commencement of chest compressions, decreases time to rescue breathing on respiratory arrest but not
cardiac arrest, decreases time to complete first CPR cycle of 30 compressions and 2 rescue breaths, and
decreases time to diagnosis of both respiratory and cardiac arrest.
○ Increased
○ Probably
Nil
increased
Equity
What would be the
impact on health
inequities?
Research evidence
● Uncertain
○ Probably
reduced
○ Reduced
○ Varies
Additional
considerations
Criteria
Judgements
Research evidence
In adults, the recommendation of CAB in preference to ABC will be acceptable to resuscitation
key stakeholders as there is no significant deviation from current practice. In children, there is
international variability so a recommendation of CAB in preference to ABC will create debate.
Is the option
Acceptability acceptable to key
stakeholders?
○ No
○ Probably no
● Uncertain
○ Probably yes
○ Yes
○ Varies
ANZCOR BLS flowchart recommends assessing response, open airway, assess breathing if
unresponsive and not breathing normally, commence 30 chest compressions followed by 2
rescue breaths and continue 2V:30CC BLS for both ADULTS and CHILDREN.
ERC BLS flowchart for ADULTS recommends assessing response, open airway, assess breathing
and if not breathing normally to commence 30 chest compressions followed by 2 rescue
breaths, then continue with 2V:30CC BLS. In CHILDREN ERC recommends assessing response,
open airway, assess breathing and if not breathing normally to deliver 2 rescue breaths, assess
for signs of life and if absent, commence 15 chest compressions and continue with 2V:15CC
BLS.
AHA BLS flowchart for ADULTS recommends assessing response, assess breathing, commence
chest compressions followed by 2 rescue breaths, then continue with 2V:30CC BLS. In
CHILDREN, assess response, assess breathing, check pulse. If lone rescuer, commence 30
chest compressions followed by 2 rescue breaths and continue 2V:30CC BLS. If two rescuers,
15 compressions followed by 2 ventilations and continue 2V:15CC BLS.
Resuscitation Council of Asia??
Feasibility
Is the option
feasible to
implement?
○ No
○ Probably no
○ Uncertain
● Probably yes
○ Yes
○ Varies
In light of above statement, the recommendation of CAB in preference to ABC will be feasible
in adults as there is no significant deviation from current practices. In children, feasibility will
be more problematic given the degree of international variation in BLS guidelines.
Additional
considerations
Recommendation
Should CPR beginning with compressions first (30:2) vs. CPR beginning with ventilation first (2:30) be used for
adults and children who are in cardiac arrest in any setting ?
Balance of
consequences
Type of
recommendation
Undesirable consequences
clearly outweighdesirable
consequences in most settings
Undesirable consequences
probably outweigh desirable
consequences in most
settings
The balance between
desirable and undesirable
consequences is closely
balanced or uncertain
Desirable consequences
probably outweigh
undesirable consequences
in most settings
Desirable consequences
clearly outweigh
undesirable consequences
in most settings
○
○
●
○
○
We recommend against offering this
option
We suggest not offering this
option
We suggest offering this option
(CAB in preference to ABC)
We recommend offering this option
○
○
●
○
There were no human studies identified in this review. This review identified four manikin studies; one randomised study [Marsch 2013 p w13856]
focused on adult resuscitation, one randomised study focused on paediatric resuscitation [Lubrano 2012 p1473] and two observational studies
focused on adult resuscitation [Sekiguchi 2013 p1248; Kobayashi 2008, p333]. Compared to previous worksheet in 2010, this review identified
three new studies that were included for analysis [Marsch 2013 p w13856; Lubrano 2012 p1473 and Sekiguchi 2013 p1248]. Overall, the
reviewers had serious concerns for trial methodology of included studies. The nature of comparing two different resuscitation protocols meant that
all studies suffered from performance and detection bias as healthcare professionals were not blinded to the intervention (CAB vs ABC).
Recommendation
For the important outcome of “time to commencement of chest compressions” we identified very low quality evidence from one randomised
manikin study [Lubrano 2012 p1473] representing 155 2-person teams and very low quality evidence from two observational manikin studies
[Sekiguchi 2013 p1248; Kobayashi 2008, p333] representing 40 individual rescuers [Sekiguchi 2013 p1248] and 33 6-person teams [Kobayashi
2008, p333]. All studies were downgraded due to risk of bias. All studies found that CAB decreased the time to commencement of chest
compression. The randomised trial found a statistically significant 24.13 second difference (p<0.05) in favour of CAB [Lubrano 2012 p1473]. The
observational studies found statistically significant decreases of 20.6 seconds (p<0.001) [Sekiguchi 2013 p1248] and 26 seconds (p<0.001)
[Kobayashi 2008, p333] respectively.
For the important outcome of “time to commencement of rescue breaths” we identified very low quality evidence from two randomised manikin
studies [Marsch 2013 p w13856; Lubrano 2012 p1473] representing 210 2-person teams. Both studies were downgraded due to risk of bias.
Lubrano [2012 p1473] found a statistically significant 3.53 second difference (p<0.05) in favour of CAB during a respiratory arrest scenario
however in a cardiac arrest scenario, ABC decreased the time to commencement of rescue breaths by 5.74 seconds (p<0.05). Marsch [2013 p
w13856] found that CAB decreased time to commencement of rescue breaths by 5 seconds (p=0.003). The clinical significance of these
differences is unknown.
For the important outcome of “time to completion of first CPR cycle” (30 chest compressions and 2 rescue breaths) we identified low
quality evidence from one randomised manikin study [Marsch 2013 p w13856] representing 55 2-person teams. Marsch [2013 p w13856] found
that CAB decreased time to completion of first CPR cycle by 15 seconds (p<0.001). The clinical significance of this difference is unknown.
For the important outcome of “time to assess responsiveness” we identified very low quality evidence from one randomised manikin study
[Lubrano 2012 p1473] representing 155 2-person teams. Lubrano [2012 p1473] there was no difference between CAB and ABC in time taken to
assess responsiveness 3.26 ±0.63 seconds vs 3.2 ±0.73 seconds (p=NS).
For the important outcome of “diagnosis of arrest” we identified very low quality evidence from one randomised manikin study [Lubrano 2012
p1473] representing 155 2-person teams. Lubrano [2012 p1473] found that CAB decreased the time to diagnosis of respiratory arrest by 1.69
seconds (p<0.05) and cardiac arrest by 24.19 seconds (p<0.05).
TREATMENT RECOMMENDATION:
We suggest a CAB as a preferable resuscitation algorithm to ABC for adults and children in cardiac arrest in any setting (weak recommendation,
very low quality of evidence).
Values and preferences statement: In making this recommendation in the absence of human data, we placed a high value on time to specific
elements of CPR (chest compressions, rescue breathing, completion of first CPR cycle).
Justification
For all outcomes CAB resulted in faster times to key elements of resuscitation (rescue breaths, chest compressions, completion of first CPR cycle)
across all papers reviewed, with the exception of simulated paediatric resuscitation where CAB delayed time to commencement of rescue breaths
in CARDIAC ARREST by 5.74 seconds – statistically significant but questionable clinical significance [Lubrano 2012 p1473]. This may be a
reasonable trade off given the other gains, bearing in mind the quality of evidence is very low and all studies reviewed were manikin studies.
There should also be consideration given to training requirements of a single approach vs separate approaches for adults and children.
Subgroup
considerations
None
Implementation
considerations
N/A
Monitoring and
evaluation
N/A
In adults and children who are in cardiac arrest in any setting (P), does CPR beginning with compressions first (30:2) (I), compared with CPR
Research
possibilities
beginning with ventilation first (2:30) (C), change survival with favorable neurological/functional outcome at discharge, 30 days, 60 days, 180
days AND/OR 1 year, survival only at discharge, 30 days, 60 days, 180 days AND/OR 1 year, ROSC AND/OR CPR quality AND/OR time to
resuscitation (O)?
References
1.
2.
3.
4.
Meursing BT, Wulterkens DW, Kesteren RGv. The ABC of resuscitation and the Dutch (re) treat. Resuscitation. 2005;64(3):279-286.
Nolan JP, Soar J, Baskett PJ. The 2005 compression–ventilation ratio in practice: Cycles or time? Resuscitation. 2006;71(1):112-114.
Handley AJ, Koster R, Monsieurs K, Perkins GD, Davies S, Bossaert L. European Resuscitation Council Guidelines for Resuscitation 2005: Section 2. Adult basic life support and use of automated external defibrillators.
Resuscitation. 2005;67:S7-S23.
Australian Resuscitation Council. Guideline 8: Cardiopulmonary Resuscitation. Melbourne: Australian Resuscitation Council. Retrieved 28 January 2014 www.resus.org.au;2011.