BACKGROUND
The usual role of CHT/CHRNs is to support a clinical wound care and hyperbaric medicine program.  In this capacity, CHT/CHRNs are called on to conduct tissue oximetry studies as a part of the physician’s assessment of the patient.  The studies are performed in the wound care or hyperbaric medicine departments. 

Tissue oxygen tension is a direct, quantitative assessment of the oxygen available to tissue.  Tissue oxygen studies are used in medical decision making by wound care and hyperbaric medicine specialists.  Several types of oximeters have been used, but most common is the noninvasive transcutaneous oximeter. Transcutaneous oximetry (TcPO2) has gained importance as a non-invasive tool for predicting potential candidates for hyperbaric oxygen (HBO2) therapy.  Clinicians use these data as an aid in vascular assessment to help predict non-responders to treatment and to choose successful amputation sites.  The data are also used to select candidates for HBO2 by identifying the presence of tissue hypoxia, and the responders to hyperoxia.  In some instances tissue oxygen data are used to determine when HBO2 treatment is complete.

PURPOSE
This TCOM Module is designed to insure that CHT/CHRN candidates have a working knowledge of the TCOM equipment and procedures.  It contains learning objectives and guidelines for demonstrating competency.

DISCLAIMER
This TCOM module is not designed to certify in TCOM.  It is the responsibility of the facility to determine competency of persons performing TCOMs.  Instruction on interpretation of TcPO2 data is outside the scope of this module.

Learning Objectives:

1. Trainee should be able to demonstrate a working knowledge of TcPO2 technology

1. Principles of transcutaneous oximetry
2. Applications for TcPO2

2. Trainee should be able to demonstrate a working knowledge of a TcPO2 monitor and its ancillary equipment

1. Operating functions of the monitor, including settings and adjustments
2. Calibration procedure
3. Procedure for maintaining the membrane and electrode
4. Describe trouble shooting procedures

3. Trainee should be able to demonstrate knowledge of a TcPO2 test that is consistent with current industry standards

1. Anatomy of the most common TcPO2 sites
2. Site seletion
3. Site preparation
4. A comprehensive TcPO2 study that will identify baseline TcPO2 values and  TcPO2 responses to physiologic challenges
5. Reference information obtained during TcPO2 tests
6. Anticipated normal TcPO2 values
7. Regional Perfusion Index (RPI)
8. Range of values that might result in acceptance of a patient for HBO2 treatment
9. Effects of common testing errors on TcPO2 values obtained

4. Trainee should be able to demonstrate knowledge of obtaining the subject’s consent for the TcPO2 procedure

5. Trainee should be able to demonstrate knowledge of inspection procedures for equipment needed to conduct a TcPO2 study

1. Oriani, G, Campagnoli P, Sacchi, C, Measzza D, Ronzio A, Montino O, Micheal M, Morandini M, and Muzzolon F.  Rational Use of the TcPO2 during HBO.  Proceedings of the XIXth Annual Meeting of EUBS 1993, Trondheim, Norway.
2. Clarke D, Transcutaneous monitoring of pO2 in hyperbaric medicine. Patient focus circle. Copenhagen, Denmark: Radiometer Medical A/S, 1997.
3. Sheffield, PJ.  Measuring Tissue Oxygen Tensions: A Review.  Undersea and Hyperbaric Medicine, 1998; 25(3): 179-188.
4. Simanonok, J.  Transcutaneous Oximetry.  Triage, Winter, 1996.
5. Wattel, FE, Mathieu, DM, and Neviere, RR.  Transcutaneous Oxygen Pressure Measurements.  Journal of Hyperbaric Medicine, 1991; 6(4): 269-282.
6. Reading material from TCOM equipment manufacturers

The TCOM Module and the application to challenge the certification examination can be obtained from the National Board of Diving and Hyperbaric Medical Technology (NBDHMT), 1816 Industrial Blvd., Harvey, LA  70058 ph. (504) 328-8871, e-mail: nbdhmt@bellsouth.net.

CHT/CHRN applicants must complete a NBDHMT approved Hyperbaric Medicine Introductory Course and the prescribed clinical internship in hyperbaric medicine.  As part of the prescribed clinical internship, CHT/CHRN applicants must complete this TCOM Module if not included in Introductory Course. Steps that the CHT/CHRN candidate should take to complete the TCOM
module before applying for certification:

• Read the learning objectives.
• Study the enclosed TcPO2 references.
• Study the operating manual of the TcPO2 monitor.
• Complete the TCOM module.
• Complete the TCOM module post-test.
•  Attach to the CHT/CHRN application: (1) a letter from the present employer, administrator, or medical director that certifies completion of the TCOM module; (2) a copy of the TCOM module post-test.

For CHT/CHRN’s who were board certified prior to implementation of this TCOM module, applications for re-certification must include: (1) a letter from the present employer, administrator, or medical director that certifies completion of the TCOM module; (2) a copy of the TCOM module post-test.

1. Trainee should be able to demonstrate a working knowledge of TcPO2 technology

1. Describe the principles of transcutaneous oximetry including:
   

1. Function of the electrode
2. Physiological effect of the heating element
3. Potential risk to the subject

2. Recite the applications for TcPO2 monitoring

1. Screen small/large vessel disease
2. Evaluate healing potential
3. Screen hyperbaric therapy candidates
4. Evaluate correction of hypoxia

2. Trainee should be able to demonstrate a working knowledge of a TcPO2 monitor and its ancillary equipment

1. Describe the operating functions of the monitor, including settings and adjustments
2. Explain the calibration procedure
3. Describe the proper procedure for maintaining the membrane and electrode

1. Explain how to change the membrane
2. State the frequency of membrane changes
3. Describe how to clean and disinfect the electrode

4. Describe trouble shooting procedure for

1. Alarms
2. Error Codes

3. Trainee should be able to demonstrate knowledge of a TcPO2 test that is consistent with current industry standards

1. Describe the anatomy of the most common TcPO2 sites

1. Vascular supply
2. Bones and Tendons

2. Describe how to determine site selection

1. Anatomical characteristics
2. Skin characteristics
3. Peri-wound characteristics

3. List 3 steps of site preparation

1. Remove hair
2. Remove loose dry skin
3. Cleanse skin to remove oils and dirt

4. Explain how to perform a comprehensive TcPO2 study that will identify baseline TcPO2 values and TcPO2 responses to 3 physiologic challenges

1. Baseline with normobaric air
2. Physiologic challenges

1. Elevated extremity challenge with normobaric air
2. Normobaric oxygen challenge with 100% O2
3. Hyperbaric O2 challenge with 100% O2

5. Explain why reference information is obtained during TcPO2 tests

1. Control sites
2. Contra-lateral sites

6. List the anticipated normal TcPO2 values

1. Chest
2. Leg
3. Foot

7. Explain how to calculate a Regional Perfusion Index (RPI)
8. List a range of values that might result in acceptance of a patient for HBO2 treatment

1. Regional Perfusion Index values
2. Peri-wound values

9. Explain the effects of common testing errors on TcPO2 values obtained

1. Positioning of patient
2. Patient talking
3. Room temperature in test area
4. Inconsistent electrode temperature with serial readings
5. Inconsistent electrode placement with serial readings
6. Inadequate time for electrode equilibration
7. Inadequate oxygen supplied during physiologic challenge
8. Improper adhesion of electrode to skin surface
9. Inadequate extremity elevation

4. Trainee should be able to describe how to obtain the subject’s consent for the TcPO2  
            procedure

1. Explain the planned procedure
2. Explain the risks involved
3. Explain the benefits

5. Trainee should be able to inspect the equipment needed to conduct a TcPO2 study

1. Monitor
2. Electrode
3. Ancillary Equipment

1. Oxygen source
2. Oxygen delivery device
3. Calibration Gas (if applicable)

6. Trainee should be able to conduct a TcPO2 test that is consistent with current industry
             standards

1. Set up the oxygen monitor

1. Temperature setting
2. pO2 / pCO2 setting (if applicable)
3. Re-membrane electrode
4. Calibrate electrode

2. Prepare the subject

1. Brief the subject
2. Obtain subject’s consent
3. Position subject for test

3. Prepare the site

1. Select the site to be measured
2. Prepare the site for accepting the electrode
3. Adhere the electrode to the skin surface

4.   Collect the data

1. Baseline TcPO2 on normobaric air
2. Physiologic challenge (any 1 of 3 below)

1. Elevated extremity challenge on normobaric air
2. Normobaric oxygen challenge on 100% oxygen
3. Hyperbaric oxygen challenge with 100% oxygen

5. Record the data

1. Complete data sheet or input information to computer
2. Calculate RPI

6. Remove Electrode

1. Remove adhesive device
2. Clean electrode
3. Store electrode