TCOM Flashcards
What is normal Tcom reading
• Normal is 50-90 mmHg
o Depends on the body area being measured
What is Tcom
• AKA TCOM, TCPO2
• Measure the tissue oxygen level in mmHg
o AKA tissue tension
• Approximate arterial capillary O2
Uses for Tcom
o Screen for vascular disease o Identify healing potential o Selection of amp level o Selection of possible HBO patients o Monitor ventilated HBO patients
Predictive value of Tcom
• Predictive value
o Better prediction of healing failure than of healing success
o Hypoxic tissue does not spontaneously heal
Electrode on Tcom
- Consists of the electrolyte solution, gas permeable membrane and the elastic ring
- Placed on the patient with a fixation ring, contact liquid, and the electrode head
Heating element of Tcom
• Causes oxygen to leak from the patient o Heat causes the dilation of pores o Heat causes the dilation of capillaries o Hemoglobin releases oxygen o Oxygen is less soluble in a liquid o The electrode is able to measure the oxygen leaking from the patient • More heat = more oxygen leak • Max temp is 45 C/113 F • Have to be careful of causing a burn • Opinions vary on best temp.
What to avoid with Tcom
• Avoid:
o Sharp curvatures on body, the fixation ring won’t bend much, it will leak
o Drainage – fixation ring won’t stick, wil leak
o Hair – can be a pathway for leaks
o Deep wrinkles – fixatino ring won’t conform down into the cracks, it will leak
o Plantar surface or a callous – skin too thick for oxygen to permeate
o Edema – oxygen won’t travel far enough through the fluid space to be measured
o Major vessel – electrode heat will cool quickly, causing an unstable temp profile
Reference site for Tcom
Reference or control site
• Area of good perfusion, close to central circulation
• Usually the left 2nd intercostals space
Regional perfusion index
RPI = Distal site pO2 divided by reference site pO2
o Ex – reference site pO2 = 80, L BKA pO2 = 40, RPI = 40/80=0.5
Site prep for Tcom
Site prep
• Shave hair
• Clean with alcohol
• Remove dead skin with tape
• Caution:
o If oils or debris are not removed, the fixation ring will not stick securely
o Tape stripping can cause a skin tear on fragile skin
o Removing the fixation ring can cause a skin tear on fragile skin
Expected Tcom behavior
Trouble shooting/expected tcom behavior
• When the electrode is placed into the fixation ring, the pO2 value on the monitor should begin to fall rapidly
• The pO2 value will reach the min value in about a minute
• After a minute, the value will begin to rise until it reaches a stable plateau
• This can take up to 15 minutes
• Normal value is 50-90 mmHg
Tcom, values are zero
The pO2 value may fall to zero and not rise – need to correlate with clinical presentation to see if it suggests that there is no circulation under the electrode.
o In a patient with a normal clinical presentation, this could indicate an error.
o Check for patient positioning that restricts circulation (pillow under knee)
o Electrode head compressing the skin
o Barrier wipe applied to skin
o Loose skin or other debris
o Insufficient amount of contact liquid
o Bad membrane
o Old electrolyte solution
Pt breathing room air and Tcom values rise to room air values
o Probably a leak
o Check to see if fixation ring is sealed to skin
o Check for skin wrinkles under the fixation ring
o Loose skin or other debris
o Also possible the electrode head is not attached properly
How to check for leaks on Tcom.
• To test for leaks
o Use oxygen via nasal canula or tubing to “blow by” the electrode – will cause a spike in pO2 values if there is a leak
Patient considerations with Tcom
Do not place patient in the supine position
• Do not elevate the patient too high
• Do not elevate legs
• Keep extremities covered – chilly air will cause vasoconstriction
