View source for Transcutaneous paCO2 Monitoring

Transcutaneous CO<sub>2</sub> (TC-CO<sub>2</sub>) monitors function by measuring the CO<sub>2</sub> which diffuses out the skin.  Modern TC-CO<sub>2</sub> monitors are a highly accurate, non-invasive method for estimating paCO<sub>2</sub>.<ref name="Nassar2017">Nassar BS, Schmidt GA. [https://doi.org/10.1513/AnnalsATS.201701-034FR '''Estimating Arterial Partial Pressure of Carbon Dioxide in Ventilated Patients: How Valid Are Surrogate Measures?'''] Ann Am Thorac Soc. 2017 Jun;14(6):1005-1014. doi: 10.1513/AnnalsATS.201701-034FR. PMID: 28570147.</ref><br>
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== Primary Purpose ==
YKDRH obtained TC-CO<sub>2</sub> monitors for the purpose of monitoring paCO<sub>2</sub> <u>trends</u> in patients receiving high-flow nasal cannula or non-invasive ventilation (i.e. CPAP/BiPAP).  This was necessary because end-tidal CO<sub>2</sub> monitoring is not compatible with these interventions.


== Important Points ==
# Applicable for all age groups (including extremely premature neonates).
# Initial reading requires approximately five minutes to establish.
# TC-CO<sub>2</sub> is '''substantially more accurate''' than peripheral venous CO<sub>2</sub> for estimating paCO<sub>2</sub>.<ref name="Nassar2017"/>
# Because CO<sub>2</sub> takes several minutes to diffuse out of the skin, the displayed TC-CO<sub>2</sub> reading at any given time reflects the paCO<sub>2</sub> from 2-4 minutes prior.
# The tracing is a flat line (rather than the waveform created by exhaled air).
# TC-CO<sub>2</sub> is used to follow paCO<sub>2</sub> trends; it DOES NOT measure instantaneous levels.  Therefore, TC-CO<sub>2</sub> '''IS NOT''' an acceptable substitute for ET-CO<sub>2</sub> in situations such as:
## Confirmation of ET-tube placement.
## CPR (neither for CPR adequacy nor ROSC identification).
## Respiratory monitoring during sedation.
## Any situation where monitoring for apnea or any rapid changes in paCO<sub>2</sub>.
# The accuracy of end-tidal CO<sub>2</sub> as an estimate of paCO<sub>2</sub> is largely dependent upon how closely a patient's lung function matches an ideal lung.  For patients who are intubated for non-respiratory issues, their lung function should pretty closely approximate an ideal lung, and thus end-tidal CO<sub>2</sub> should estimate paCO<sub>2</sub> with reasonable accuracy.  But for patients with lung processes which create V/Q mismatches, end-tidal CO<sub>2</sub> is not a good estimate of paCO<sub>2</sub>.  In such situations, TC-CO<sub>2</sub> provides a MUCH MORE ACCURATE estimate paCO<sub>2</sub>.<ref name="Nassar2017"/>  Thus, if paCO<sub>2</sub> requires monitoring in patients with ARDS, bronchiolitis, pneumonia, etc., TC-CO<sub>2</sub> should be considered regardless of the type of respiratory support the patient is receiving (i.e. none, high-flow, or intubated).  In such a situation, an intubated patient might be monitored with end-tidal CO<sub>2</sub> to watch for apnea and TC-CO<sub>2</sub> to assess adequacy of ventilation over time.
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== Device ==
YKDRH has acquired the '''Sentec''' Digital Monitoring System.<br>
The Sentec devices provides monitoring of:
# Instantaneous oximetry (with an adjustable duration trend line)
# Instantaneous heart rate (with an adjustable duration trend line)
# Delayed paCO<sub>2</sub> (with an adjustable duration trend line)

== Resources ==
: [https://yk-health.org/wiki/File:Transcutaneous_CO2_monitor_SDMS_InstructionManual_EN.pdf Sentec Instruction Manual]
'''Instructional Videos:'''
: [https://www.youtube.com/watch?v=7d7XNtQNllA Sensor Application Neonatal for the Sentec Digital Transcutaneous Monitoring System]
: [https://www.youtube.com/watch?v=7HX7dgqieaM Sensor Application Adult Cheek for the Sentec Digital Transcutaneous Monitoring System]
: [https://www.youtube.com/watch?v=7PeoOWAtWss Sensor Application Adult Upper Arm for the Sentec Digital Transcutaneous Monitoring System]
: [https://www.youtube.com/watch?v=DLWEH-2VHZc Changing the Sensor Membrane for the Sentec Digital Transcutaneous Monitoring System]
: [https://www.youtube.com/watch?v=zCc4JZsfKZM Sentec Digital Transcutaneous Monitoring System Demonstration]

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'''PubMed Searches:'''
: [https://pubmed.ncbi.nlm.nih.gov/?term=(%22transcutaneous%20co2%22%5BTitle%5D%20OR%20%22transcutaneous%20carbon%20dioxide%22%5BTitle%5D)%20AND%20(infant%5BTitle%5D%20OR%20neonat*%5BTitle%5D%20OR%20child*%5BTitle%5D) ("transcutaneous co2"[Title<nowiki>]</nowiki> OR "transcutaneous carbon dioxide"[Title<nowiki>]</nowiki>) AND (infant[Title<nowiki>]</nowiki> OR neonat*[Title<nowiki>]</nowiki> OR child*[Title<nowiki>]</nowiki>)]
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== REFERENCES ==
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