Duration of resuscitation
1 2 1. 5 2. 5 3
13% Never 16%
used for TOR regarding the use of EtCO2
levels for medical decision-making.
The average importance of EtCO2 in TOR
decisions on a scale of 1 (least importance)
to 10 (greatest importance) was 6.77, but
this value doesn’t reflect a general consensus.
Although 71% of participants felt that EtCO2
was important (i.e., rated > 5) in TOR decisions, 29% don’t think that EtCO2 plays an
important role (i.e., rated ≤ 5) in the decision
to terminate resuscitative efforts.
The second question showed that there’s
no real consensus with regard to ranking the
importance of the listed clinical factors in the
decision to terminate resuscitation.
The survey also revealed that more than
85% of participants believe the role of EtCO2
in TOR has changed in the past decade, and
84% of agencies have terminated resuscitation in cardiac arrests where EtCO2 is > 20
This finding reveals that the threshold of
EtCO2 < 10 mmHg at the 20-minute mark
of resuscitation as the predictive marker of
non-survivability of OHCA, which was set
as a result of the 1997 article discussed previously, may need to be re-evaluated.
With improvements in resuscitative methods, there are several potential confounders
regarding the increased level of EtCO2 in
TOR cases, including higher-quality CPR,
use of automated compression devices, underlying respiratory cause for the arrest and the
administration of sodium bicarbonate.
It’s interesting to find such a wide variety of opinions among expert EMS medical directors when it comes to determining
which clinical factors are most important
for TOR. This variability could affect survival, as under- or over-emphasizing specific
clinical factors could result in premature
termination or inappropriately prolonged
The authors believe that the various factors used in the decision for TOR in the
out-of-hospital setting should be standardized for all patients.
The survey results confirm the lack of standardization in guidelines used for TOR and
suggest that the use of EtCO2 levels as a guide
in determining field TOR may need further
examination. Further research may clarify
both the role of EtCO2 as well as potential
pitfalls of its use in TOR. JEMS
Alysha Joseph, BS, is a medical student at the University of
Texas Southwestern Medical Center.
Brandon Morshedi, MD, is an EMS fellow in the Department
of Emergency Medicine at the University of Texas Southwest-
ern Medical Center.
Raymond L. Fowler, MD, FACEP, DABEMS, is professor and
chief of the Division of Emergency Medical Services in the
Department of Emergency Medicine at the University of
Texas Southwestern Medical Center.
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Figure 2: Average importance of specific clinical factors in TOR
Figure 3: How often are resus-
citative efforts terminated
with EtCO2 > 20 mmHg?
Figure 4: Has the role of EtCO2 in
TOR changed over the past decade?