1) Applied respiratory physiology examines the links between basic respiration and clinical manifestations of respiratory diseases, including respiratory adjustments to health stresses, disturbances of respiration, artificial respiration, and pulmonary function tests. 2) Disturbances of respiration include abnormal respiratory patterns like tachypnea and apnea, as well as issues related to respiratory gases and pulmonary diseases. 3) Specific abnormal respiratory patterns discussed include eupnea, tachypnea, bradypnea, polypnea, apnea, hypoventilation, hyperventilation, hyperpnea, and dyspnea.

1. Respiration
Applied Aspects

2. INTRODUCTION
Applied respiratory physiology forms
a link between the basics of respiration and
clinical manifestations of respiratory diseases.
The important applied aspects of respiration
include:
• Respiratory adjustments to stresses in health
• Disturbances of respiration
• Artificial respiration
• Pulmonary function tests.

3. DISTURBANCES OF RESPIRATION :
• Abnormal respiratory patterns
• Disturbances related to respiratory gases
• Pulmonary diseases: pathophysiological
aspects.

4. • ABNORMAL RESPIRATORY PATTERNS
• Eupnoea refers to normal respiratory pattern, which
implies a normal rate, rhythm and depth of respiration.
Various terms used for the altered pattern of respiration
are:
• Tachypnoea refers to increase in the rate of respiration.
• Bradypnoea means decrease in the rate of respiration.
• Polypnoea is used to denote the rapid but shallow
breathing.
• Apnoea refers to temporary cessation of breathing.

5. • Hypoventilation term is used to describe a
decrease in rate and force of respiration.
• Hyperventilation refers to increase in rate as well
as force of respiration.
• Hyperpnoea, signifies a marked increase in
pulmonary ventilation due to increase in rate
and/or force of respiration.
• Dyspnoea: When hyperpnoea involves 4-5 fold
increase in pulmonary ventilation, an unpleasant
sensation or discomfort is felt. This type of
respiration is called dyspnoea.
• Periodic breathing refers to a respiratory pattern
characterized by alternate periods of respiratory
activity and apnoea.

7. • APNOEA: Apnoea refers to temporary cessation of
breathing.
Depending upon the cause apnoea may be of following
types:
• Voluntary apnoea refers to temporary arrest of
breathing due to voluntary control of respiration.
It is also called breath holding. The breath-holding
time or apnoea time during which breathing can be
withheld voluntarily is about 40-60 seconds in a normal
person, after a deep inspiration.
• Apnoea after hyperventilation occurs due to reduced
stimulation of respiratory centre owing to CO2 wash
caused by hyperventilation.

8. Deglutition apnoea
• Occurs reflexly during swallowing.
• During pharyngeal stage of swallowing the fluid
or food stimulates the sensory nerve endings(5th,9th
and 10th cranial nerves) around the pharynx.
• Nerve impulses from these irritant receptors, via
the swallowing centres specifically inhibit the
respiratory centre stopping the breathing at any
point of the cycle(Deglutition apnoea).
• Simultaneously, there is closure of glottis(the
opening between vocal cords).
• Both these effects prevent aspiration of fluid or food
into the lungs.

10. • Breath-holding attacks
• Vagal Apnoea:
• produced by stimulation of Vagus nerve.
• Produces Apnoea by inhibiting Inspiratory centre
• Adrenaline Apnoea
• Sleep Apnoea :
• Temporary cessation of breathing during sleep
due inhibition of central chemoreceptors.
Sleep Apnoea syndrome occurs in two forms:
Obstructive sleep apnoea
Non-obstructive(central) sleep apnoea

12. • DYSPNOEA
• Dyspnoea literally means distressed
breathing. Increased respiration without
discomfort is called hyperpnoea.
• When hyperpnoea involves 4-5 fold increase in
pulmonary ventilation, an unpleasant sensation
or discomfort is felt.
This type of respiration is called dyspnoea.
The word ‘air-hunger’ is used as synonym
to dyspnoea in general language.
• Dyspnoea point refers to the height of
hyperpnoea at which dyspnoea appears.
• Types:

13. • Predisposing factors for dyspnoea include:
• Low vital capacity
• Maximum ventilatory volume(MVV)
• Breathing reserve(BR) = MVV-RMV=114 L/min
Individuals with less BR are prone to Dyspnoea
• Dyspnoeic index(DI) refers to breathing reserve
percentage of MVV,
DI = BR*100/MVV=110*100/120=95%
Normal = 70-95%
DI<60% dyspnoea occurs
• Normal value of DI range from 70-95%
• Dyspnoea occurs when DI is <60%

14. • Causes of Dyspnoea :
• Physiological : Severe muscular excersise.
• Pathological –
(i) Respiratory disorders
(ii)Cardiac failure -
ORTHOPNOEA:
Dyspnoea occurring in lying down
position is called Orthopnoea.
(iii)Metabolic disorders

15. • Cardiac failure
• Pulmonary congestion Decreased vital
capacity
• Tachypnoea
• Increased pulmonary ventilation
• Dyspnoea

16. PERIODIC BREATHING

17. • Periodic breathing:
• Periodic breathing is characterized by alternate periods of
respiratory activity and apnoea.
It is of 2 types-
• Cheyne-Stokes respiration and
• Biot’s breathing
• Cheyne-Stokes respiration:
• Characterized by alternate periods of respiratory activity and
apnoea at regular intervals.
• During respiratory activity there is waxing and waning of tidal
volume.
• Duration of one cycle – 1 minute.
• pO2 is lowest pCo2 is highest at the end of apnoea.

19. Causes:
• Physiological: Voluntary hyper ventilation
High Altitude
During sleep in infants
• Pathological: Chronic heart failure
Brain damage
Uremia
Poisoning by narcotics.
Mechanism:
• Voluntary hyperventilation
• Cardiac failure
• Brain damage

21. Biots breathing-
• Also known as Ataxic breathing shows alternate
periods of respiratory activity and apnoea
• Occurring at irregular intervals.
• No waxing and waning of tidal volume.
• It is always pathological
• cannot be physiological.
Causes:
• Disruption of normal medullary rhythmicity of
respiration.
• meningitis ,head injury,
• medullary compressions,
• central medullary lesions.

22. BREATH HOLDING

23. • Breath holding:
• Voluntary control of respiration mediated by a
pathway from neocortex by passing the
medullary respiratory centres to project
directly on spinal respiratory neurons
exercised during some activities like talking,
singing, swimming.
• Breath-holding time-60-50 seconds.
• It can be prolonged by 50-20 seconds by
initial hyperventilation which lowers the
arterial pCO2

24. Breath holding attacks in infants & young
children:
• Precipitated by emotional stress like fright, fear,
cry, pain, frustration, anxiety etc.
• The child starts crying suddenly holds the
breath becomes stiff, blue, lose consciousness.
• Brief & recovery is rapid and complete.
• Harmless & stop by the age of 3 yrs.

25. ASPHYXIA

26. • Asphyxia means lack of O2 together with excess of CO2
Hypoxia + Hypercapnia.
• The causes of asphyxia can be divided as follows:
Local asphyxia:
complete obsruction /ligation of blood vessels.
General asphyxia
Acute Asphyxia:
Strangulation,
drowning,
choking,
paralysis of diaphragm
Chronic Asphyxia:
Cor pulmonale: RVF due to Respiratory Disease
There are 3 stages of Asphyxia.

27. 1st Stage – 1 minute (stage of hyperpnoea):
• Here CO2 excess only is the stimulant which will stimulate the
respiratory center
• increased rate of respiration.
2nd stage – (stage of central excitation)-2 min.
• Here the stimulating factor is both hypoxia & excess of CO2
• becomes unconscious
• 1. Increased heart rate
• 2. Increased B.P
• 3. Increased saliva secretion
• 4. Increased deep reflex action.
• Here the breathing becomes difficult and expiration
prolonged.
3rd stage — stage of central depression (3 min)
• This is due to lack of O2
• heart rate decreased, BP decrease, reflexes
• lost. Finally respiration becomes short and gasping and finally
death

28. DROWNING

29. • Drowning is asphyxia caused by immersion,
usually in water.
• There are 2 mechanisms by which drowning
leads to death –
Asphyxia
Flooding of lungs with water
• In about 10% of drowning, the first gasp of
water after the losing struggle not to breathe
triggers laryngospasm, and death results from
asphyxia without any water in the lungs.

30. • In the remaining cases, the glottic muscles
eventually relax and fluid enters the lungs.
• Fresh water is rapidly absorbed, diluting the
plasma and causing intravascular hemolysis.
• Ocean water is markedly hypertonic and
draws fluid from the vascular system into the
lungs, decreasing plasma volume.
• The immediate goal in the treatment of
drowning is, of course, resuscitation, but long-
term treatment must also take into account
the circulatory effects of the water in the
lungs.