A left shift in the oxyhemoglobin dissociation curve is caused ...

[charchew]

A left shift in the oxyhemoglobin dissociation curve is caused by:
 
  a. methemoglobin.
  b. acute acidosis.
  c. increased temperature.
  d. high 2,3-diphosphoglycerate (2,3-DPG).

Question 2

The blood gas factor results from the:
 
  a. Slow rate of oxygen diffusion in fluids.
  b. Slow rate of carbon dioxide diffusion in blood.
  c. Amount of carbon dioxide necessary to change the pH by 0.01.
  d. Quantity of electrons that need to be added to the silver anode to reduce oxy-gen.

[scottmt]

Answer to Question 1

ANS: A
Methemoglobin will increase hemoglobin's affinity, causing a left shift in the oxyhemoglobin dissociation curve. Acute acidosis, hyperthermia, and increased levels of 2, 3-DPG will decrease hemoglobin affinity.

Answer to Question 2

ANS: A
When blood samples are analyzed, the consumption of oxygen by the electrode leads to an un-derestimation of the partial pressure of oxygen in a blood sample by 2 to 6. This phenomenon is due to the slow rate of oxygen diffusion in fluids (i.e., oxygen consumed by an electrode is not replaced by oxygen from the blood). The magnitude of the blood gas factor depends on the di-ameter of the cathode and the thickness of the membrane between the sample and the cathode.