Chapter 11 - Transcutaneous oximetry

Question 1

Principle of transcutaneous oximetry TcPO2

Answer 1

Reflects tissue oxygen tension which depends on balance between oxygen supply and consumption

Determines wound healing and amputation level

Question 2

Limitations of TcPO2

Answer 2

1) difficulty keeping electrode flat
2) inability to place electrode on skin that is not intact or edematous
3) inability for patient to lie quietly for 20 min

Question 3

Physical principle of TcPO2

Answer 3

1) electrode has heating element that heats skin
2) melts away lipid layer in fatty tissue
3) vasodilation increases flow to capillaries raising oxygen content
4) diffusion of oxygen to surface
5) sensor in electrode measures oxygen coming through the skin
6) Chemical reaction and measures as PO2 in mmHg

Question 4

Technique of TcPO2

Answer 4

1) Supine
2) clean skin site
3) Attach adhesive ring, electrolyte solution, sensor
4) Time elapses for calibration

Question 5

TcPO2 sensor cannot be placed in these locations

Answer 5

1) edematous skin
2) ulcers
3) cellulitis
4) skin close to bone

Question 6

TcPO2 with oxygen challenge define

Answer 6

oxygen given to patient during test to increase sensitivity

Question 7

Definition of TcPO2 cutoff for normal foot

Answer 7

> 50 mmHg

Question 8

TcPO2 for impaired wound healing

Answer 8

< 40 mmHg

< 50 mmHg if diabetic or renal failure

Question 9

CLTI TcPO2 level

Answer 9

< 20-30 mmHg