Ventilation Flashcards
What are the 2 parts of tidal volume?
Dead Space Volume
Alveolar Volume
What is the formula for tidal volume?
VT = VA + VD
What is the formula for minute volume?
VE = F x VT
What does VE represent
Minute volume exhaled
What is the formula for alveolar minute volume?
VA = (VE - VDphy) X F
What is the formula for physiological dead space?
VDphy = VDanat = VDalv
What is the formula for physiological dead space that includes mechanical dead space?
VDphy = VDanat + VDmech
What formula allows you to compute a percentage of tidal volume due to physiological dead space?
VD/VT= PACO2 - PECO2 / PACo2
What is the formula for VD/VT ratio which is clinically used to measure physiological dead space?
VD/VT = PACO2 - PECO2/ PaCO2 x (VT)
What breathing pattern provides the most alveolar ventilation?
Slow, deep breaths
What breathing pattern results in the least efficient alveolar ventilation?
High respiratory rates, low tidal volumes
What breathing pattern must be used to compensate when physiological dead space occurs?
Larger tidal volumes
What happens if a person is unable to compensate for an increase in physiological dead space?
CO2 will be retained & value will begin increasing, alveolar ventilation will decrease
respiratory acidosis will result
What is the relationship between alveolar ventilation & PaCO2?
there is an inverse relationship
What is the formula used to find this relationship?
PaCO2 = VCO2 x .863 / VA
A person’s anatomical dead space is equal to ____ mL per pound?
1 ml per pound
1 kg = _____ lbs
2.2 lbs
A patient is breathing a tidal volume of 600 mL and a RR of 12/min. What is the alveolar minute volume if the patient weighs 150 lbs?
5400 mL or 5.4 L
A patient has an expired tidal volume of 600 mL. If the patient’s weight is 120 lbs what is the estimated alveolar tidal volume?
480 mL
Given: VT = 780 mL; VD = 160 mL; RR 14 min; Calculate the VE & VA
VE = 10.9 L VA = 8.7 L
A patient weighs 130 pounds and has a VT of 610 mL and a RR of 16 min. What is the estimated dead space volume (VD). What is the calculated alveolar minute volume?
VD = 130 ml
VA 9.76 L
Given the following: VT = 800 mL; VD = 200 mL, RR = 10 min; What is the minute volume (VE)
8 L
How do you calculate ideal body weight for males & females:
Male = ?
Female = ?
Male = 106 + (6 x # of inches over 60") Female = 105 + (5 x # of inches over 60")
What is a normal tidal volume in a health patient?
500 ml
What is a normal minute volume?
6000 ml
What is a normal physiological dead space?
150 ml
What is a normal alveolar ventilation?
4200 ml
When you increase your tidal volume to compensate for increased dead space what happens to your minute volume (VE) and alveolar volume (VA)?
VE will increase
VA remains the same
If you increase your rate of breathing to 24 breaths a minute what happens to tidal volume? minute volume? & alveolar ventilation?
Tidal volume will decrease
minute volume stays the same
Alveolar ventilation will decrease
If you have an increased dead space with a normal tidal volume what happens to your minute ventilation & alveolar ventilation?
VE is unchanged
VA will decrease
If you decrease your rate of breathing with no change to your dead space what happens to tidal volume, minute volume & alveolar ventilation?
Tidal volume will increase
Minute volume stays the same
Alveolar ventilation increases
What is the formula for Alveolar Ventilation?
Alveolar Ventilation = VT - VD
T or F: Alveolar dead space is perfused but does not participate in gas exchange
True
In a diseased condition such as pulmonary embolism what happens to the VD/VT ratio?
It will increase
What is the ratio of PACO2 to alveolar ventilation?
Inversely related
If your alveolar ventilation is reduced by half what happens to the PACO2?
It will double
T or F: A patient cannot be tachypneic & hypoventilating at same time
False; a patient can be tachypneic & hypoventilating at same time
Where does the anatomical dead space occur?
In the conducting airways
What 3 things result from compensation for increased physiological dead space?
Increased tidal volume
increased elastic work of breathing
increased O2 consumption
What gauge needle is used for ABG blood draw in an adult patient?
20 - 23 gauge needle
What gauge needle would you use for a pediatric patient?
25 gauge needle
In terms of gauge size what is a very small diameter needle?
25 gauge
What would a large diameter needle size be?
20 gauge
Which type of needle produces better results on an ABG, glass or plastic?
neither
Why would you immerse a sample in ice?
if you were unable to test the sample at the bedside
Why is a blood sample iced?
It will slow the metabolism of WBC & RBC making the results more accurate
What types of diseases should you be concerned with when taking an ABG sample?
thrombocytopenia, DIC (desiminated intravascular coagulation), Raynaulds disease, hemophilia
Name 4 sites that can be used for arterial blood draws?
Radial, brachial, dorsalis pedis, femoral
What is the preferred site for ABG draws?
Radial
What is the 2nd choice for ABG draw?
Brachial
This site might be used if you have a burn trauma victim because no other site available?
Dorsalis pedis
What is the risk of using the Femoral artery?
no collateral circulation, patient could loose leg if a clot would result
What is the purpose of the modified allens test?
to determine collateral circulation
What does a positive modified allens test mean?
That you have sufficient circulation from the ulnar artery
What does a negative allens test mean?
That the circulation is poor & you must notify the doctor
When you puncture the artery the Bevel should be pointing in what direction?
Bevel should be up at 45 degree angle
What should you do when you see a flash?
Do not move, stop advancing, the syringe will fill by pressure gradient
The rate in which the syringe will fill is dependent on what?
patients blood pressure
What color should the blood appear if it is oxygenated?
Bright red
What does dark red blood mean?
It could be deoxygenated, it could be venous blood or it could mean the patient is hypoxic
If you puncture a site & you have no blood pressure & the syringe plunger is barely moving what does this mean?
That you may have hit a vein instead of artery
When you advance or move a needle is it ok to change the angle if the artery is rolling?
No, you never change angles in a patients arm
How many times can the needle be moved & in what direction?
Twice, in the lateral or medial direction
What does it mean if you see your flash & then it stops?
Either you passed through the artery or you are in the wall; or you hit a vein
How much blood is normally obtained with an ABG?
1-2 cc
How long should you apply pressure in a normal patient?
Up to 5 min
If a patient is taking Coumadin, or heparin what would you need to do?
Apply pressure up to 15 minutes or until bleeding stops
T or False; You never recap a needle.
True
RBC consumption of O2: 100 mL of blood will consume .1 ml of O2 every ______ min at body temp
10 minutes
The temperature of the ice bath is approx.?
4 degrees C
After you withdraw blood there are two other things you must do to ensure an accurate result?
Remove excess heparin
Expel air bubbles
T or F Once you have gathered your blood sample you would cover with a band aid?
False
What are some hazards to arterial blood draws?
Hematoma Arterial occlusion Arteriospasm Infection Trauma to artery Vasovagal response Pain Can hit radial nerve/nerve damage
What should you do if the patient has a renal dialysis shunt?
Use the other arm
If the patient has had a mastectomy how will that affect your ABG?
You would use the other side
Rank the sites based on safety to patients:
1 Radial
2 Brachial
3 Dorsalis Pedis
4 Femoral
What must be recorded with an ABG sample?
Temperature
What should be recorded at time of ABG sample?
Temperature
FIO2
Respiratory Rate
O2 device
What will an air bubble do to your results
Air bubbles will change your result; mechanism is the diffusion gradient
If you increase your tidal volume will this decrese your anatomical dead space?
No, your anatomical dead space is a fixed quantity
This is a disease which causes lungs to become stiff and hard to stretch which limits tidal volume & causes a dimished pulmonary reserve
Fibrosis
With a disease such as emphysema why would you see a patient with elevated Co2 levels?
they slow down their metabolic needs; they have alveolar dead space & anatomic dead space; wasting O2 gets low O2 blood levels & increasing CO2
