Author Question: Which of these two parameters does a pulse oximeter measure? 1. O2Hb 2. Hb 3. COHb 4. MetHb a. 1 ... (Read 11 times)

APUS57 · **on:** Jul 16, 2018

Which of these two parameters does a pulse oximeter measure? 1. O2Hb 2. Hb 3. COHb 4. MetHb

a. 1 and 2
b. 1 and 3
c. 2 and 3
d. 3 and 4

Question 2

Which of the following describes the filling pressure of the ventricle at the end of ventricular di-astole?

a. Preload
b. Afterload
c. Dicrotic notch
d. Ejection fraction

vseab · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: A
Pulse oximetry provides continuous, noninvasive measurements of arterial oxygen saturation. A sensor is placed over a digit, an earlobe, the forehead or the bridge of the nose; this sensor measures the absorption of selected wavelengths of light beamed through the tissue (Fig. 10-1). For example, oxyhemoglobin can be differentiated from deoxygenated hemoglobin by shining two wavelengths of light (660 and 940 nm) through the sampling site. As Figure 10-2 illustrates, at a wavelength of 660 nm (red light), deoxygenated hemoglobin absorbs more light than oxy-hemoglobin. Conversely, oxyhemoglobin absorbs more light at 940 nm (infrared light IR) than does deoxygenated hemoglobin.

Answer to Question 2

ANS: A
The definition of preload is the filling pressure of the ventricle at the end of ventricular diastole.