Adult, primary cardiac arrest cases
Survived to discharge
shockable or ROSC
Transported to hospital
Survived to discharge
but relied on an interaction with presenting
rhythm. Therefore, this wasn’t included in
The two remaining variables had a strong
association with outcome; ROSC (OR =
40. 3; 95% CI: 25.8% to 62.7%), and initial
shockable rhythm (OR = 10. 8; 95% CI: 6.7%
Independently, ROSC had a positive predictive value of 99% and a specificity of 97.9%,
and a presenting shockable rhythm had a positive predictive value of 97.4% and a specificity of 80.7%.
However, 4.7% (n = 24) of survivors didn’t
attain ROSC before hospital arrival, and
18.3% (n = 80) of survivors didn’t present
with a shockable rhythm.
Therefore, neither of these of these variables could be used independently as a prediction tool. As a result of this we included
both initial shockable rhythm and ROSC in
the TOR CDR.
The derived TOR CDR proposes TOR
for adult OHCA of presumed cardiac cause
where the presenting rhythm isn’t a shockable rhythm, and where no ROSC is achieved
before transport. All other patients required
transport for ongoing resuscitative efforts.
Retrospective application of this guideline to
our sample indicated that all but five survivors
were identified for transport. (See Figure 3.)
The five survivors equate to 0.2% of those
terminated, which is below the threshold of
1% for futile interventions. 17 The CDR would
have resulted in transport rate of 52.5%.
Against this sample, the BLS and ALS
CDRs discussed previously resulted in fewer
unexpected survivors ( 3 BLS and 2 ALS survi-
vors, respectively). However, this is at the cost
of increased transport rates ( 63.1% BLS and
90.2% ALS, respectively). (See Table 3, p. 56.)
The issue of TOR in OHCA requires a balance between the need to achieve survival
wherever possible, and the unnecessary use of
limited resources for transporting and treating patients who have no chance of survival.
The transport of OHCA entails substantial
costs and involves risk due to emergency blue-light transportation. Transport also removes
the ambulance from other operational duties,
which prevents its availability to other patients
with potentially treatable conditions.
Once a patient in refractory cardiac arrest
arrives at the receiving hospital, hospital clinicians are required to attend and are then
unavailable to other patients.
There’s a need to balance the disadvan-
tages of futile transportation with the need
to recognize patients who have a chance of
survival. U.K. guidelines allow for the termi-
nation of patients in asystole, but there are
no guidelines for those who remain in PEA.
The 2015 Resuscitation Council (U.K.)
guidelines state that in most circumstances
where ROSC is not achieved before transport
and where ALS has addressed any potentially
reversible causes, there’s little to be gained
from transporting the patient to a hospital. 14
However, the guidelines also state, “There is
limited evidence to support when one should
terminate a PEA cardiac arrest… .” 18
Although TOR guidelines for OHCA have
been validated, 5, 7, 8 these were produced for
EMS systems different from the U.K., and
they don’t necessarily reduce transportation12
or they recognize too few potential survivors19
when assessed in alternative systems.
The guideline proposed here reduced the
transportation rate to 52.4%, and of the 2,264
Table 2: Logistic regression predicting survival
Bystander CPR -0.079 0.137 0.566 0.924 0.707 1.209
Bystander witnessed 0.3 0.157 0.057 1.349 0.992 1.836
Clinician witnessed 1.232 0.198 0 3. 43 2.327 5.054
Shockable 2.368 0.244 0 10.676 6.619 17. 22
Defibrillated 0.208 0.25 0.405 1.231 0.754 2.01
ROSC 3.692 0.226 0 40. 11 25.749 62.483
Constant - 6.537 0.273 0 0.001
Figure 3: Application of termination of resuscitation guideline