Oxygen is essential to life. All cells in the body require
it, some being more sensitive than others. A person
whose oxygen needs are meet adequately is not aware
of the process of respiration.
The word oxygen comes from the Greek word
meaning “acid former “because most mineral acids
and carboxylic acids contains oxygen.
Oxygenation means the delivery of oxygen to the
body’s tissues and cells. It’s necessary to maintain
health and life.
The term oxygen was first coined by Antoine
ANCIENT HINDU CONCEPT OF OXYGEN
The presence of lungs had been recognized in ancient Hindu
medicine. Both Charaka and Susrata the two famous
physicians/ surgeons of the vedic period
(500)BC,RECOGNIZED A ‘PRANA VAYU’, I.E LIFE AIR.
Charaka mentions the head , the chest, the ears, the tongue,
the mouth and the nose as the seat of ‘prana vayu’.Susrata
(1000)BC spoke of ‘ prana vayu’ as flowing in the mouth.
ANCIENT GREEK CONCEPT
In the 4th century BC,ARISTOTLE identified
few essential elements – earth ,air, fire and
water. The need for air remained well
organized ,although its role was not
MODERN HISTORY OF OXYGEN
:Paracelsus, a Swiss scientist had suggested in 1541 that air
contained a life sustaining substance.
Priestley called oxygen as the deep dephlogisticated air
Thomas beddoes used oxygen for the first time in early
1800 for treatment of medical disorders.
Larynx: these voice organ that connects the pharynx
and trachea .
the major function of the larynx is the vocalization.
protects the lower respiratory system from foreign
substance and facilitates coughing
It consist of the following
arytenoid cartilage and
Glottis: The opening between the vocal cords in the larynx.
Cricoid cartilage : The only complete cartilaginous ring in
the larynx. (located below the larynx)
Arytenoid cartilage: These are used in the vocal cord
movements with the thyroid cartilage.
Vocal cords: It produces sounds which are located in the
lumen of the larynx
Trachea: These are called the wind pipe which is composed
of the C shaped rings made of cartilages running down at
regular intervals. it serves as a passage between larynx and
LOWER RESPIRATORY TRACT
These are paired structures enclosed inside
the thoracic cage which is a air tight chamber with
When the capacity of the chest is increased air enters
through the trachea (inspiration) because of the lower
pressure within and it inflates the lung.
When the chest wall and the diaphragm return to
their respiration (expiration) the lungs recoil and force
PHYSIOLOGY OF RESPIRATION
Air enters through nose, where it is warmed humidified and
Inspired air passes from the nose through pharynx
After this air moves to trachea passing through larynx
Trachea branches into two bronchi
Through bronchi air enters into the lungs and moves
through primary bronchi and smaller bronchi
Ending with the terminal bronchioles and then
Respiratory gas exchange
Respiratory gases are exchanged in the alveoli and the
capillaries of the body tissues.
Oxygen is transferred from the lungs to the blood and
carbondioxide is transferred from the blood to the
At the tissue level, oxygen is transferred from the
blood to tissues, and carbon dioxide is
transferred from tissues to the blood to return to
alveoli and be exhaled.
Movement of gases from higher concentration to the
area of lower concentration.
Alveoli capillary layer enhances the diffusion to take
place during the ventilation without any difficult.
OXYGEN TRANSPORT AND
Oxygen needs to be transported from the lungs
to the tissues and carbon dioxide must be
transported from the tissue to the lungs.
Normally most of the oxygen combines mostly
with the hemoglobin in the red blood cells
and its carried to tissues as oxyhemoglobin
Actual blood flow through the pulmonary circulation.
The passage of oxygen from the atmosphere to the Alveoli
and the passage of carbon dioxide from the alveoli to the air
require an uninterrupted air way.
Anything that interferes with the patency of any part of the
respiration tract can interfere with the efficiency of
Normally the cough is the mechanism by which the
respiratory tract is cleared off the foreign materials.
Obstruction in the trachea, pharynx, larynx and bronchi can
stimulate the cough reflex.
Some patients have difficulty in clearing the mucous
from the bronchial tree, perhaps because it is painful to
cough because of lack of strength or because of
At any rate, fluids can accumulate and require nursing
intervention for their removal.
Continual bed rest and maintaining a prone can
contribute to this difficulty by limiting chest expansion
and alveolar ventilation
The pumping action of the heart is essential to
maintaining oxygen deliver The four chambers of
heart fill during diastole and empty during systole.
The myocardial fibers have contractile properties that
enable them to stretch during filling.
In a healthy heart this stretch is proportionally
related to the strength of contraction.
In the diseased heart, starling's law does not apply
because the stretch of the myocardium is beyond the
heart’s physiological limits.
MYOCARDIAL BLOOD FLOW
To maintain adequate blood flow to the pulmonary and
systemic circulation myocardial blood flow must supply
sufficient oxygen and nutrients to the myocardium itself.
Blood flow through the heart is unidirectional.
There are four heart valves that ensure this forward blood
ATRIOVENTRICULAR VALVES (MITRAL AND TRICUSPID )
BLOOD FLOW FROM HIGHER PRESSURE ATRIA INTO THE
IT REPRESENTS S1 OR THE FIRST HEART SOUND
AFTER VENTRICULAR FILLING THE SYSTOLIC PHASE BEGINS
BLOOD FLOWS FROM VENTRICLE INTO THE AORTA &
CLOSURE OF PULMONIC &AORTIC VALVES REPRESENTS S2 OR
THE SECOND HEART SOUND
CORONARY ARTERY CIRCULATION
Blood in the atria and ventricles does not supply oxygen and
nutrients to the myocardium itself.
The coronary circulation is the branch of the systemic
circulation that supplies the myocardium with oxygen and
nutrients and removes waste.
the coronary arteries fill during ventricular diastole . the
right and the left coronary arteries arise from the aorta just
above and behind the aortic valve through openings called
the coronary ostia.
The rhythmic relaxation and contraction of the
atria and ventricles depend on continuous,
organized transmission of electrical impulses.
these impulses are generated and transmitted by
way of the cardiac conduction system.
The conduction system originates with the
sinoatrial node(SA),the “pacemaker” of the heart
CONDUCTION SYSTEM CONTD…
Impulses are initiated at the SA node at an intrinsic rate of 60
to 100 beats per minute. The resting adult rate is
approximately 75 beats per minute.
An electrocardiogram (ECG) reflects the electrical activity
of the conduction system.
PRINCIPLES RELEVANT TO
Oxygen is essential to life.
A person can survive only a few minutes without oxygen.
An insufficient supply of oxygen impairs functioning of al
Irreparable brain damage may result from prolonged
periods of inadequate oxygen.
Cells of the cerebral cortex begin to die as soon as they are
deprived of oxygen.
Air at sea level containing approximately 20% of oxygen
and 0.04% carbon dioxide is sufficient to meet man’s
7.Carbon di oxide concentrations between 3 and 10 %
increase the rate and depth of respirations.
8.The body’s ability to meet its oxygen needs depends on
the adequacy of functioning of the cardiovascular and
the respiratory systems.
9.A patent airway is essential to normal respiratory
10.The respiratory tract is lined with mucus secreting
11.Coughing, swallowing and sneezing are mechanisms by
which the body attempts to rid itself of foreign materials
in the respiratory tract.
12.Difficulty in breathing provokes anxiety.
CAUSES OF OXYGEN INSUFFICIENCY
& FACTORS AFFECTING
The fluid filled lungs
DECREASED OXYGEN CARRYING CAPACITY
inhalation of toxic
decreases the oxygen
carrying capacity of
pallor and an
increased heart rate.
is there both
changes can affect
the fingers, toes,
and around the
Physical activity or
exercise increase the
rate and depth of
Smoking affects the
altitude heat, cold and
air pollution affect
oxygenation. The higher
the altitude lowers
is the pCo2 a patient
breaths. Air pollution
causes head ache,
coughing even in
including sedative ,
using inspection techniques the nurse performs the head to
toe observation of the client for the skin and the mucus
membrane , colour , general appearance, level of
consciousness, breathing pattern and chest wall movement.
Inspection includes observation of the
nails for clubbing
the chest wall movement for retraction
paradoxical breathing , asynchronous breathing and the
clients breathing pattern
clients effort during respiration, when especially distress or
flaring of noses, position distress
palpation of the chest provides assessment data's in several
allows the nurse to feel for abnormal masses or any lumps in
the axilla and the breast tissue.
Palpation of the extremities provides the data about the
peripheral circulation, the presence and the quality of the
peripheral pulses, skin temp, capillary refill and colour.
Palpation should also include the feet and the legs to assess
the presence or absence of peripheral edema palpation of the
pulses in the neck and extremities is performed to assess the
arterial blood flow
It allows the nurse to detect the presence of abnormal fluid
or air in the lungs.
It is also used to determine the diaphragmatic excursion
it may reveal hyper resonance , dull percussion tone or
changes in the density of the lungs and the surrounding
It enables the nurse to identify the normal and abnormal
fluid in heart and lung sounds.
Auscultation of the cardio vascular system should include
the assessment of normal s1 and s2 sounds, the presence of
abnormal s3 and s4 sounds (gallops), and murmurs or rubs.
Auscultation of lung sounds involves listening for the
movement of air throughout all lung fields ; anterior ,
posterior and lateral.
Adventitious breath sound appears when there is a
collapse of the lung segment, fluid in a lung segment or in
case of narrowing or any obstruction of the airway.
also evaluates the clients response
intervention for improving their respiratory status.
ABG helps in the measurement of blood for patients arterial
sputum is obtained for analysis to identify the pathogenic
organism and to determine malignancy or hypersensitivity
which in turn is helpful to determine the causes for oxygen
The sputum may also be collected through endotracheal
aspiration, bronchoscopal aspiration etc… the specimen are
usually collected in the early morning en and carbon dioxide
To assess the fluids , tumor, foreign bodies and other
It’s the direct inspection and examination of the larynx ,
trachea and bronchi through a fibrotic flexible
bronchoscope. The therapeutic bronchoscope are used to
Remove foreign from trachea bronchial tree
Remove secretions obstructing the tracheal esophageal tree
To destroy and excise tumor
a sample of the pleural fluid is obtained by the thoracentesis
for both diagnostic and therapeutic purposes.
By, thoracentesis pleural fluid is studied for Grams stain
culture and sensitivity, acid fast staining and culture,
differential cell count, cytology, pH, specific gravity, total
pulmonary angiography is most commonly used to
investigate thrombotic disease of lungs, such as pulmonary
emboli and abnormalities of vascular trees.
It involves a rapid injection of a radio opaque agent into the
vasculature of the lungs for radiographic study of the
pulmonary vessels through femoral vein, or branches of
pulmonary artery and images are taken and analyzed
these are used to assess the respiratory functions and to
determine the extent of dysfunction.
These are used to find the;
volume of the air in the lungs
speed and ease of air flow via airways
strength of the respiratory muscle
The PFT is performed by the technician using a spirometer
that has a volume collecting device attached to a recorder
that demonstrates the volume and time simultaneously.
MOBILIZATION OF THE PULMONARY
Hyperventilation- it occurs when rapid and deep
breathing results in excess of CO2 (hypocapnia).
Causes of hyperventilation include anxiety
, infection, shock, hypoxia, drugs
(aspirin,amphetamines), diabetes mellitus, or acid
base imbalance. A person who is hyperventilating may
complain of feeling of lightheaded and tingly.
Hypoventilation- it occurs when the rate and depth
of respiration are decreased and CO2 is retained or
alveolar ventilation is compromised. Hypoventilation
may be related to chronic obstructive pulmonary
disease(COPD), general anesthesia, or other
conditions that results in decreased respiration
CLINICAL PRESCRIPTION OF OXYGEN
Oxygen like a drug is used for most of the indications.
It is generally used as an additional supplement to the
other forms of drug therapy. In many other disease
where oxygen deficiency is a major abnormality,
oxygen constitutes the mainstay of therapy. Oxygen
prescription or delivery was associated with
significantly minor errors than those seen with the
antibiotics. It is important to consider oxygen as a drug
to get the maximum benefit. It is important to have
oxygen therapy protocols and education programs
especially for the nursing staff.
METHODS OF OXYGEN DELIVERY
It is the most common inexpensive method used to
administer oxygen to client.it delivers a relatively low
concentration of oxygen (24% to 45%)at flow rate of 2-6 l/mt.
But this is not in use nowadays. In these days nasal prongs
The simple face mask delivers oxygen concentrations from 40% to
60%at flow rate of 5 to 8L/min respectively.
The face mask is sub divided into two types namely
NON REBREATHER MASK
In rebreather mask the oxygen the oxygen reservoir
bag that is attached allows the client to rebreath the
exhaled air in conjunction with oxygen. Thus it
increases FiO2(fractional oxygen of inspired air) by
recycling expired oxygen.
Non rebreather mask
It delivers the highest oxygen concentration possible
95% to 100% by means other than intubations or
mechanical, at liter flow of 10 to 15 L/min.
It delivers oxygen concentration varying from 24% to 40% or
50%at flow rate of 4 to 5 lit /min. The venturi mask has wide
tubing and colour coded jet adaptors that correspond to a
precise oxygen concentration and flow rate
Trans tracheal delivery
This is used for oxygen dependent clients. Oxygen
is delivered through a small, narrow plastic
cannula surgically inserted through the skin
directly into trachea.a collar around the neck
holds the catheter in place. Advantage-with the
method client requires less oxygen (0.5 to 2 L/
min) as 5ml of saline twice or thrice a day.
face tents: it can be used for clients who cannot
tolerate masks. these provide 30% to 50% oxygen
concentration at a flow rate of 4 to 8 L/ min. nurse
should frequently of flow is delivered directly to lungs.
The nurse keeps the catheter patent by injecting 1.5 ml
of normal saline with it. Moving a cleaning rod in and
out and then reinjecting 5ml of saline twice or thrice a
In medicine, mechanical ventilation is a method to
mechanically assist or replace spontaneous breathing. This
may involve a machine called a ventilator or the breathing
may be assisted by a physician, respiratory
therapist or other suitable person compressing a bag or set
of bellows. There are two main divisions of mechanical
ventilation: invasive ventilation and non-invasive
ventilation.There are two main modes of mechanical
ventilation within the two divisions: positive pressure
ventilation, where air (or another gas mix) is pushed into
the trachea, and negative pressure ventilation, where air is
essentially sucked into the lungs
The exact oxygen concentration being delivered is
usually difficult to know for this reason it can best
assessed by the flow rate (FiO2) and by the type of
mask being used to the patient. The fiO2 required to
be delivered based upon the acuteness of illness and
the severity of the hypoxemia. One must avoid a high
fiO2 for prolonged period to avoid toxicity.
SOURCE OF OXYGEN
Compressed gas cylinders continues to be used in
hospitals in our country. Piped system with wall
outlets from the central sourceis made available in
large hospitals. A knowledge about the cylinders,
regulators, flow meters and the pressure guage is
much important for the nurses for an efficient role
Application and duration
It can be used as a short term measure, for example during an
operation or critical illness (often in the setting of an intensive care
unit). It may be used at home or in a nursing or rehabilitation
institution if patients have chronic illnesses that require long-term
ventilatory assistance. Owing[clarification needed] to the anatomy of the
human pharynx, larynx, andesophagus and the circumstances for
which ventilation is required then additional measures are often
required to secure the airway during positive pressure ventilation to
allow unimpeded passage of air into the trachea and avoid air passing
into the esophagus and stomach. Commonly this is by insertion of a
tube into the trachea which provides a clear route for the air. This can
be either an endotracheal tube, inserted through the natural openings
of mouth or nose or a tracheostomy inserted through an artificial
opening in the neck. In other circumstances simple airway maneuvres,
an oropharyngeal airway or laryngeal mask airway may be employed. If
the patient is able to protect their own airway and non-invasive
ventilation or negative-pressure ventilation is used then a airway
adjunct may not be needed
Types of ventilators
Negative pressure ventilation
This exerts the negative pressure on the external
chest; which in turn decreases the intra thoracic
pressure during inspiration and allows the air to flow
into the lungs., thereby filling its volume. These are
mainly used in clients with neuro muscular conditions
Advantage-easy to use and doesn’t require intubation
Disadvantage- unsuitable for patients who require
frequent ventilation changes
METHODS OF OXYGEN DELIVERY
It is the most common inexpensive method used to
administer oxygen to client. it delivers a relatively low
concentration of oxygen (24% to 45%)at flow rate of 26 l/mt.
But this is not in use nowadays. In these days nasal
prongs are used.
Positive pressure ventilation
These inflates the lungs by exerting
pressure on the airways, forcing
the alveoli to expand during
inspiration. Expiration occurs
passively which further includes
cycled ventilatiors, pressure cycled
ventilators and volume cycled
Modes in ventilators
CMV- continous mandatory volume without allowances for spontaneous breathing
ACV- assist control ventilation; where assisted breaths are followed by controlled
IMV- intermittent mandatory ventilation; are those which mixes controlled breath
and spontaneous breaths.
PSV- pressure support ventilation; this is where the patient has the complete
control over all the aspects of his/her breaths except the pressure limits
HIGH FREQENCY VENTILATION- where mean airway pressure is maintained
constantly and hundreds of tiny breaths are delivered /min.
CPAP- continous positive airway pressure; spontaneous ventilation with continous
positive airway pressure . this ventilator is adjunct and is used only with
spontaneous ventilation. i.e the patient breaths spontaneously through the
ventilator at an elevated baseline pressure throughout the breathing cycle.
SIMV-synchorinized intermittent mandatory ventilation; a present a minimum
number of breaths are synchronously delivered to the patient but the patient may
also take spontaneous breaths of various volume. Note how the inspiratory and
expiratory pressure differ between spontaneous and ventilator breaths.
PEEP-positive and expiratory pressure; airway pressure with varying levels of
positive and expiratory pressure. Note that at he end of the expiration, the airway is
not allowed to return to zero.
The simple face mask delivers oxygen concentrations
from 40% to 60%at flow rate of 5 to 8L/min respectively.
The face mask is sub divided into two types namely:
In rebreather mask the oxygen the oxygen reservoir bag
that is attached allows the client to rebreath the exhaled
air in conjunction with oxygen.thus it increases
FiO2(fractional oxygen of inspired air) by recycling
Non breather mask:
It delivers the highest oxygen concentration possible 95%
to 100% by means other than intubations or mechanical,
at liter flow of 10 to 15 L/min.
It delivers oxygen concentration varying from 24% to
40% or 50%at flow rate of 4 to 5 lit /min. the venturi
mask has wide tubing and colour coded jet adaptors
that correspond to a precise oxygen concentration and