Week 8-6 Flashcards
How is oxygen carried in the blood?
Dissolved in plasma
Bound to 4 hemoglobin chains
Visible difference in oxygenated vs deoxygenated blood?
Oxy-Hemoglobin- red
Deoxy- Hemoglobin- blue
Describe spectrophotometry?
The use of light waves to measure absorption to find patients O2 saturation
The two wavelengths used during spectrophotometry
Red-660
Infrared-940
Three types of hemoglobins
Carboxyhemoglobin
Oxyhemoglobin
Methemoglobin
Methemoglobin pattern
At 660 it is absorbing red wavelength
At 940 it is also absorbing more than the other hemoglobin
Oxyhemoglobin pattern?
Reflects both red and absorbs some infrared
Carboxyhemoglobin pattern?
Reflects both. Especially at 940
Two types of spectrophotometry?
Transmittance spectrophotometry
Reflectance spectrophotometry
How does pulse oximetry single out arterial blood?
Since the venous blood is consistent, when the heart pumps, it creates a variable that the sensor reads.
What should we look at to deem a pt. monitor as accurate?
Do heart rates match?
Are wave forms uniform?
Is the carrot full?
Common problems encountered with pulse oximetry?
Ambient light
Infrared radiation
Poor pulse strength/irregular
Nail polish
Artifact
Normal range of error for pulse oximetry?
+ or - 4
Lowest SpO2 with a degree of reliability?
80<
Hemoglobin conditions that can provide false readings?
Carboxyhemoglobin- carbon monoxide
Methemoglobin- to high or low
Define mass
Amount of matter is an object/substance
Define atomic weight?
Weight of protons and neutrons
Define atomic weight?
Weight of protons and neutrons
Atomic number?
Based on number of protons
Molecular weight?
The sum of the atomic weights of the constituent atoms
Gram atomic weight?
The mass of one mole of an atom expressed in grams
Equation for density
Mass/volume
What properties of X-rays that allows it to penetrate skin?
Uses HIGH electromagnetic radiation carried by photons
Define exposure?
The exposure of radiation to the body to produce a internal silhouette
Define density in regards to production to X-rays
The state of matter and atomic mass that creates thickness that the photons must go through absorbs the photons to create the silhouette.
Define radiolucenct
Matter that is clear through x-ray
Define radiopaque
Matter that stops photons from reaching detector
How does the heart look during a AP image?
Larger
Radiation does go straight, it is spread out
Which projection do we take X-rays?
Posterior-anterior
Why do we take a full inhalation during X-ray?
Can lead to misdiagnosed lung opacities
Why is it important to remember a X-ray is two dimensional?
Things outside body can show up.
(Diagnosis is governed by density, thickness and exposure. Instead of layers of body tissue).
Other names for X-rays?
CXR, plain films, chest roentgenograms.
Formula for BMI?
Weight in kg divided by height in meters ^2
Cm to meters?
Divide by 100
Classification for BMI?
Normal <25 kg/m^2
Overweight 25-29 kg/m^2
Obese > or = 30 kg/^2
Good application of BMI
useful for the average person
And “J shaped” relationship with mortality (drastic points on the spectrum)
Shortcomings of BMI scale?
Doesn’t account for individuals physical activity level
Poor when calculating metabolic heath
PBW for men formula
50 + 2.3 [height (inches)-60]
PBW for female formula?
45.5 + 2.3 [height (inches) - 60]
What protocol do we use PBW
ARDSnet
Formula for the shock index?
HR/Systolic
Normal range for the shock index?
0.5-0.7
IBW formula for men?
106 + 6(height in inches -60)
IBW for women?
105 + 5(height in inches - 60)
Reason for poor perfusion?
Hypotension
Hypovolemia
Hypothermia
Administration of vasoconstrictor
Reason for poor perfusion?
Hypotension
Hypovolemia
Hypothermia
Administration of vasoconstrictor
