Life Functions: Ventilation & Oxygenation
The primary purpose of respiration is to inhale enough
from the atmosphere to sustain all the cells in your body.
Then to exhale enough
to remain in proper acid base balance.
This is known as HOMEOSTASIS.
There are 4 critical life functions that allow the body to stay in homeostasis.
VENTILATION: the movement of air in and out of the lungs
OXYGENATION: transporting oxygen to the blood
CIRCULATION: the movement of blood through the body
PERFUSION: getting oxygen to the tissues
On this page, we will discuss the first 2 critical life functions:
ventilation and oxygenation.
VENTILATION is the movement of air in an out of the lungs; and the #1 LIFE FUNCTION.
Why? The simple answer:
Without the movement of air in and out of the lungs (no inhalation or exhalation)
ALL of the other critical life functions will be impacted.
How does it happen? Think of the domino effect.
No ventilation = NO AIR MOVEMENT IN OR OUT OF THE LUNGS = APNEA
No oxygenation = GAS EXCHANGE CANNOT OCCUR = HYPOXEMIA
No circulation = HEART LOSES THE ABILITY TO PUMP = CARDIAC ARREST
No perfusion = CARDIAC OUTPUT & BLOOD PRESSURE FALL TO ZERO.
No breathing, no circulation, no perfusion of the brain or major body systems = DEATH
And ALL the dominoes fall!
(SO…..it’s kind of a big deal!)
VENTILATION can be measured by the following VITAL SIGNS:
RESPIRATORY RATE : how many times you breathe a minute (also called frequency/ f)
TIDAL VOLUME: measurement of a quiet breath in ml or L (abbreviated Vt)
CHEST WALL MOVEMENT: observance of the degree the chest and ribs properly expand
BREATH SOUNDS: normal or abnormal sounds during auscultation with a stethoscope over the lung fields
Abnormal sounds might include wheezing, crackles, stridor, silent chest, or pleural friction rub.
CARBON DIOXIDE REMOVAL : PaCo2 and EtCO2 are measured by an blood gas sample or capnometer
Both values increase when ventilation is not effective!
Mechanical Lung ventilation in intensive care unit
(This is why a VENTILATOR is often used to help restore proper ventilation!)
OXYGENATION, is the transporting of oxygen into the blood, and the #2 LIFE FUNCTION.
OXYGENATION can be measured by observing the following VITAL SIGNS:
HEART RATE: normal pulse rate vs abnormal (tachycardia, bradycardia, cardiac arrest, or arrhythmias)
COLOR: normal skin color vs abnormal (cyanosis, erythema, jaundice)
SENSORIUM: ability of the person to be orientated to their surroundings (hypoxemia can indicate poor sensorium)
PaO2 and SpO2: measurement of oxygen level in the blood by an blood gas sample or pulse oximeter
example of a pulse oximeter
Hypoxemia is an abnormal low amount of oxygen in the blood.
Hyperoxia is excessively high amount of oxygen in the blood.