Which of the following cause erroneous transcutaneous oxygen ...

[londonang]

Which of the following cause erroneous transcutaneous oxygen (PtcO2) readings? 1. Hypovolemia 2. Hypothermia 3. Septic shock 4. Asthma
 
  a. 1 and 3 c. 1, 2, and 3
  b. 1 and 4 d. 2, 3, and 4

Question 2

To produce capillary vasodilatation below the surface of a transcutaneous PO2 electrode, which of the following should be done to the electrode?
 
  a. Icing to 0 C c. Cooling to 25 C
  b. Heating to 44 C d. Warming to 35 C

[aliotak]

Answer to Question 1

ANS: C
Hypovolemia, hypothermia, and septic shock will decrease peripheral perfusion caused by reduc-tions in cardiac output. This can significantly affect the accuracy of PtcO2 measurements. Asth-ma does not necessarily cause a decrease in cardiac output.

Answer to Question 2

ANS: B
The transcutaneous PO2 electrode is heated to 42 C to 45 C to produce capillary vasodilatation below the surface of the electrode. Heating improves gas diffusion across the skin, because it in-creases local blood flow at the site of the electrode and alters the structure of the stratum corneum, the fibrinous tissue within a lipid-and-protein matrix. Cooling or icing the skin will de-crease blood flow to the area, making it difficult to obtain an accurate PO2. A temperature of 35 C is not warm enough to arterialize the area under the skin.

[londonang]

Excellent

[Dominic]

TYSM