IN BRIEF A Summary of the Evidence
Capnography for End-Tidal CO2 Monitoring
Key Messages
• For adult patients in a hospital who are being sedated
for a procedure:
zz Capnography enables better detection of respiratory
problems and is associated with fewer episodes of
hypoxemia (low levels of oxygen in the blood) than
standard monitoring alone.
zz Capnography may be cost-effective, depending on
local budgetary considerations.
• For other patient populations (i.e., adults receiving
cardiopulmonary resuscitation [CPR], adults in serious
or critical condition, and adults recovering from
surgery), evidence assessing the effectiveness of
capnography in relation to patient outcomes is limited.
Evidence is particularly limited or absent for pediatric
patients.
Context
Certain patients are at risk of breathing complications and
impaired blood flow. Monitoring how well a patient is breathing
and exchanging oxygen for carbon dioxide (CO2) is useful
for detecting complications such as airway obstruction,
hyperventilation, hypoventilation, or apnea. If a breathing
complication is identified quickly, health care providers can
respond accordingly to prevent the situation from becoming
more critical or fatal.
One way to monitor breathing is by measuring end-tidal carbon
dioxide (ETCO2). ETCO2 is the level of CO2 released at the end
of an exhaled breath, and it reflects how well CO2 is being
transported in the blood and airway.
Technology
Capnography devices are used to non-invasively measure ETCO2,
displaying results visually as a graph and as a number. Results
are available within seconds for each breath, making it possible
to quickly identify breathing trends. Capnography devices can be
hand-held and portable, or they can be integrated into another
IN BRIEF Capnography for End-Tidal CO2 Monitoring
piece of medical equipment. Capnography monitoring is used
with standard monitoring, which may include pulse oximetry,
pulse rate, blood pressure, and visual assessment.
Issue
Capnography has been used for decades to monitor ETCO2
in patients undergoing general anesthesia. More recently,
capnography has been used for patients undergoing milder
forms of sedation and for patients in intensive care units,
emergency rooms, and ambulances. However, access to
this technology and rates of use vary, and the link to clinical
outcomes remains unclear. A review of the current evidence on
capnography will help inform decisions about its adoption and
use.
Methods
CADTH conducted a systematic review of available evidence
since 2005. To be included, studies had to report clinical
outcomes or changes in patient management.
Clinical data from the included articles were meta-analyzed
where possible, and sensitivity analyses were conducted.
Economic evaluations of capnography were conducted
for each population and setting of interest, when possible.
Implementation issues were also examined in the literature.
Results
After screening and evaluation, 29 studies met the criteria for
inclusion in this review.
The findings showed that capnography reduced episodes
of hypoxemia in hospitalized adults undergoing procedural
sedation, at an added cost. The incremental cost was $413 per
respiratory failure avoided with capnography added to standard
monitoring, compared with standard monitoring alone. This may
be cost-effective, depending on local factors.
Evidence was limited for other populations and settings.
One study showed that outside of a hospital setting, using
capnography during CPR for adults experiencing a heart attack
improved the likelihood of restoring circulation and their survival
to arrival at the hospital. One study showed that for adult
patients recovering from surgery in a hospital, capnography
increased detection of respiratory problems. Limited evidence
suggests that, for adult patients in critical condition, death due
to misplaced endotracheal tubes may be lower with the use of
capnography.
Read more about CADTH and its review of
capnography at:
www.cadth.ca/capnography-end-tidal-co2-monitoring.
An exploratory analysis suggests that capnography may provide
better value for money than standard monitoring for adult
patients in serious or critical condition and better value for
money than standard monitoring alone for those recovering from
surgery in a hospital.
To aid implementation, barriers and supports (such as training
on capnography use) should be considered.
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DISCLAIMER
The information in this document is intended to help health care decision-makers, patients, health care professionals, health systems leaders, and
policy-makers make well-informed decisions and thereby improve the quality of health care services. This information should not be used as a substitute
for the application of clinical judgment in respect of the care of a particular patient or other professional judgment in any decision-making process nor
is it intended to replace professional medical advice. While The Canadian Agency for Drugs and Technologies in Health (CADTH) has taken care in the
preparation of this document to ensure that its contents are accurate, complete, and up-to-date, CADTH does not make any guarantee to that effect.
CADTH is not responsible for any errors or omissions or injury, loss, or damage arising from or as a result of the use (or misuse) of any information
contained in or implied by the information in this document.
CADTH takes sole responsibility for the final form and content of this document. The views expressed herein are those of CADTH and do not
necessarily reflect the views of our funders.
ABOUT CADTH
CADTH is an independent, not-for-profit organization responsible for providing Canada’s
health care decision-makers with objective evidence to help make informed decisions
about the optimal use of drugs and medical devices in our health care system.
CADTH receives funding from Canada’s federal, provincial, and territorial governments, with the exception of Quebec.
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May 2016
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