Chap 42

Disturbances of
respiration
These are due to
 Abnormal respiratory pattern
 Disturbances related to
respiratory gasses

Abnormal respiratory
pattern
 Tachypnea … Increase rate of
respiration..
 Apnoea …Temporary cessation of
breathing
 Dyspnoea…distressed breathing
 Periodic breathing…alternate periods
of respiratory activity and apnea e.g.
Cheyne stokes breathing

Cheyne-Stokes Breathing
 Is periodic type of breathing in which
alternate periods of respiratory
activity and apnoea occur at regular
intervals
 And during the period of respiratory
activity there is waxing and waning of
tidal volume
 Duration is of 1 minute
 PO2 is lowest and the PCO2 is highest
at the end of apnoea.

causes
 PHYSIOLOGICAL CAUSES
 Voluntry hyperventilation
 High altitude
 During sleep
 PATHOLOGICAL CAUSES
 Chronic heart failure
 Brain damage
 Uraemia
 Poisoning by narcotics

Sleep Apnea
 Apnea is the temporary suspension of
breathing.
 Normally, some episodes of apnea occur.
In people with sleep apnea, the episodes
are longer and more frequent.
 2 types of sleep apnea are:
Obstructive sleep apnea
Central sleep apnea

Obstructive Sleep Apnea
 In patients with sleep apnea, the pharynx is
collapsed while the muscles relax. Some of
the factors that cause this collapse include:
 Excess fat deposits in the soft tissues of the
pharynx or fat masses in the neck.
 Nasal obstruction
 Enlarged tonsils
 Very large tongue
 Certain shapes of the palate

Symptoms of Obstructive Sleep
Apnea
 Loud snoring and labored breathing that
often progressively worsens.
 Long silent periods (apnea) that cause
increases in PCO2 and decreases in PO2.
 This stimulates respiration, which
results in loud snorts and gasps.
 This repeats.

Central Sleep Apnea
 Less common than obstructive sleep apnea.
 The CNS signal to the respiratory muscles
stops.
 Can be caused by damage to the central
respiratory center or respiratory
neuromuscular junction.

Disturbances related to
respiratory gases
 Respiratory disturbances are
related to respiratory gases
include
 Hypoxia
 Hypercapnia
 Asphyxia
 Carbon monoxide poisoning

Hypoxia
Tissue hypoxia means
that the amount of
oxygen available for
cellular metabolism is
inadequate.
Hypoxia leads to
anaerobic mechanisms
that eventually produces
lactic acid and cause the
blood pH to decrease.

CAuses
 Decreased oxygen tension of the
arterial blood
 Decreased oxygen carrying capacity of
lungs
 Decreased rate of blood flow to the
tissues
 Decreased tissue utilization of oxygen

types
 Hypoxic hypoxia
 Anemic hypoxia
 Circulatory hypoxia
 Histotoxic hypoxia

Hypoxic Hypoxia
 Hypoxic hypoxia or hypoxemic hypoxia
refers to the condition in which the PO2 is
abnormally low.
 This form of hypoxia is better known as
hypoxemia (low oxygen concentration in
the blood).
 This form of hypoxia can develop from:
 pulmonary shunting - low alveolar PO2
 diffusion impairment - V/Q mismatch
15

Anemic Hypoxia
 Anemic hypoxia is when the oxygen
tension in the arterial blood is normal,
but the oxygen-carrying capacity of the
blood is inadequate.
 This form of hypoxia can develop from:
 a low amount of Hb in the blood
 a deficiency in the ability of Hb to carry O2
 Increased cardiac output is the main
compensatory mechanism for anemic
hypoxia.
16

Circulatory Hypoxia
 In circulatory hypoxia, the arterial blood
that reaches the tissue cells may have a
normal O2 tension and content, but the
amount of blood--and therefore the
amount of O2--is not adequate to meet
tissue needs.
 The two main causes of circulating
hypoxia are:
 stagnant hypoxia
 arterial-venous shunting 17

Histotoxic Hypoxia
 Histotoxic hypoxia develops in any
condition that impairs the ability of
tissue cells to utilize oxygen.
 May be due to cyanide or sulphide
poisoning
18

Characteristic features of
hypoxia
Features Hpoxic
hypoxia
Anemic
hypoxia
Circulatory
hypoxia
Histotoxic
hypoxia
PO2 in arterial
blood
Reduced Normal Normal Normal
O2 carrying
capacity of blood
Normal Reduced Normal Normal
Velocity of blood
flow
Normal Normal Reduced Normal
Utilization of blood
flow
Normal Normal Normal Reduced
Efficiency of O2
therapy
100% 75% >50% Not useful

Cyanosis
 Cyanosis is the term
used to describe the
blue-gray or purplish
discoloration seen on
the mucous
membranes, fingertips,
and toes whenever the
blood in these areas is
hypoxemic.
 When level of deoxy
Hb ≥5g/dl signs of
cyanosis may develop
21

Types of hypoxia
Peripheral cyanosis Central cyanosis

Treatment of cyanosis
Warming of the affected areas
 Peripheral cyanosis brought about by
exposure to cold or Raynaud’s phenomenon
may be treated symptomatically using
gentle warming of the fingers and toes.
Oxygenation as a treatment for cyanosis
 Initial stabilization requires oxygenation.
Sometimes a breathing machine or
ventilator might be required.

Surgery as a treatment for
cyanosis
 Treatment of central cyanosis due to
congenital heart defects may often
involve surgery.

Asphyixa
 Refers to the condition in which there
is hypoxia associated with hypercapnia
 May be due to
 strangulation
 drowning
 tracheal obstruction due to foreign
body
 paralysis of diaphragm

treatment
 First aid to remove foreign body
 Emergency resuscitation
 Expired Air Resuscitation (EAR)
 Cardio-Pulmonary Resuscitation (CPR)

pneumonia
 Inflammatory
condition of the
lung in which
alveoli are filled
with fluid and
blood cells
 There is
hypoxemia and
hypercapnea

treatment
 Most cases of pneumonia can be treated at
home. However babies, children, and people
with severe pneumonia may need to be
admitted to hospital for treatment.
 Pneumonia is usually treated with
antibiotics, even if viral pneumonia is
suspected as there may be a degree of
bacterial infection as well. The type of
antibiotic used and the way it is given will
be determined by the severity and cause
of the pneumonia.

asthma
 Asthma is a
common chronic
inflammatory
disease of the
airways
characterized by
variable and
recurring
symptoms,
reversible airflow
obstruction, and
bronchospasm.

symptoms
Common symptoms include
 wheezing,
 coughing,
 chest tightness, and
 shortness of breath.

Treatment
Bronchodilators Nebulization

tuberculosis
 Tuberculosis) is a
common infectious
disease caused by
various strains of
mycobacteria, usually
Mycobacterium
tuberculosis.
Tuberculosis typically
attacks the lungs, but
can also affect other
parts of the body

Treatment
 Anti tuberculous drugs

Chap 42

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Chap 42