# Respiratory Care Test Review Test 1

## Terms

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Describe Fick's Law
It is inversely related to the thickness across the lung membranne.
Think Think = Thick
How Would you get a PVO2 reading?
From a Swanz Ganz Catheter.
What can the P(A-a)02 gradient used to estimate?
1. the degree of hypoxemia.
2. The degree of Physiological shunt.
When is the P(A-a)O2 increased?
When Hypoxemia is due to V/Q Mismatching, diffusion defect, or shunt. In the absence of Cardiopulmonary Disease, it increases with aging.
Calculate PA02.
PA02= (PB-PH20)x FIO2 (Paco2x 1.25)
Note- drop the 1.25 if fio2 is over 60. *watch this on tests*
Water vapor pressure is how much?
47mmhg saturated at 37C
What is the normal Respiratory Exchange Ratio?
1.25 or 0.8.
What is the A/a ratio an Indicator of?
The effiency of O2 transfer.
A low A/a Ratio reflects what?
V/Q Mismatching, diffusion defect, or shunt.
What is the Normal value for the A/a Ratio?
>60%
What is the normal value for P(A-a)o2.
On room air it should be less than 4 mmhg for every 10 years in age.
What is the normal value for PA02?
It varies according to he Fi02.
What Is the C(a-v)o2 useful for?
changes is o2 consumption and Cardiac Output.
The normal o2 content difference between arterial and venous blood is about what percentage?
<5% normal patients
>6% critically ill patients with out cardiovascular compensation.
Factors that DECREASE C(a-v)02.
Increased Cardiac Output
Skeletal relaxation (induced by drugs)
Peripheral shunting (sepsis, trauma)
Certain Poisions (cyanide)
Hypothermia
Calculate V02 (oxygen consumption)amt of 02 extracted from the tissues in one minute.
Vo2= QT(C(a-v)02 x 10)
What is the normal VO2?
200-350 ml / minute
What are factors that INCREASE Oxygen consumption?
Exercise
Seizures
Shivering (post op pt)
Hyperthermia
What are factors that DECREASE oxygen consumption?
Skeletal Relaxation
Peripheral Shunting
Certain Poisions (Cyanide)
Hypthermia
What does Ca02 reflect?
The overall carrying capacity of oxygen arterial blood.
Calculate Ca02?
Ca02=(Hbx1.34xSao2) + Pao2 x 0.003)
What is the Normal value for Ca02?
16-20 V%
Which calculation requires a PA02 value?
Ca02
Calculate the 02ER.
O2ER = Cao2-CVO2/CAO2
What is the normal value for 02ER?
20-28%
What is the 02ER useful for?
Patients oxygen transport status?
What is the classic shunt equation used for?
To calculate the portion of Cardiac output not taking part in gas exchange.
Calculate MV.
RR x VT = MV
When would you have a Increased VQ mismatch?
Pulmonary Emboli and Increase CO.

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