2. Dyspnea
Mental anguish associated with inability to ventilate
enough to satisfy the demand for air ( difficulty in
breathing)
Air hunger ( occurs both in physiological and pathological
conditions)
Three major causes
1. Hypercapnia (mainly) and hypoxia ( to some extent)
2. Increased Work of breathing (exercise / Lung diseases)
3. State of mind
3. Dyspnea
Individual develops dyspnea when excess of CO2
accumulates in body fluids (difficult breathing)
When a person breath forcefully, the forceful activity of
respiratory muscles gives the person a sensation of
dyspnea
Dyspnea due to abnormal state of mind – emotional
dyspnea or neurogenic dyspnea
This is more common in people who has psychological
fear of not being able to receive adequate quantity of air
such as entering small or crowded rooms
4. Dyspneic index (DI)
Breathing reserve/ MVV x 100
MVV= maximum voluntary ventilation – 110 lit/min
Breathing reserve for a person breathing 5 lit/ min is
110-5 = 105 l/min
105/110 x100 = 95.45
When DI becomes 60 or below, then dyspnea starts
5. Hypoxia
Insufficient oxygen supply to the tissues
Hypoxia and hypoxemia are different
Classified into four classes
1. Hypoxic Hypoxia
2. Stagnant Hypoxia
3. Anemic Hypoxia
4. Histotoxic Hypoxia
6. Hypoxic Hypoxia
Occurs when PO2 of arterial blood decreases
Low barometric pressure
Diseases like
1. Gas exchange failure in the lungs
2. emphysema
3. Asthma
4. Pneumothorax
7. Hypoxic Hypoxia
Low barometric pressure occurs at high altitudes
Acute Mountain Sickness
Soldiers, who flown high up from low areas due to
urgency (a hazard faced repeatedly by Indian
Soldiers)
When pressurized cabin of aero plane become faulty
8. Hypoxic Hypoxia
Atmospheric PO2 decreases
Alveolar PO2 decreases
RBC count normal
Blood flow is normal
Tissue utilization of oxygen is normal
9. Anemic Hypoxia
Decrease in the RBC
Decrease in Hemoglobin
Decrease in the oxygen carrying capacity
Also seen in CO poisoning
CO has 250 times more affinity for hemoglobin than
oxygen
COHB will be formed and that prevents uptake of
oxygen (decreased oxygen carrying capacity)
10. Anemic Hypoxia
CO poisoning causes shift of oxygen dissociation curve
to left
CO poisoning causes hypoxia of brain – leads to head
ache
CO is present in coal gas
Also seen in CO poisoning and auto mobile exhaust
fumes ( professional drivers suffer with chronic and mild
CO poisoning)
CO poisoning can be managed by hyperbaric oxygen
therapy
11. Anemic Hypoxia
Atmospheric PO2 normal
Alveolar PO2 normal
RBC count decreased
Blood flow is normal
Tissue utilization of oxygen is normal
12. Stagnant Hypoxia
Circulation becomes very sluggish
Blood stays in the capillaries for too long period
Tissues continue to draw oxygen from capillaries
Capillary blood becomes deficient in oxygen
Occurs in Cardio vascular shock and CHF
(congestive heart failure)
13. Stagnant Hypoxia
Atmospheric PO2 normal
Alveolar PO2 normal
RBC count normal
Blood flow is decreased
Tissue utilization of oxygen is normal
14. Histotoxic Hypoxia
Inhibition of cytochrome oxidase
Occurs due to cyanide poisoning
Cytochrome oxidase is a key enzyme for tissue
oxidation
Tissue oxidation is inhibited
Tissues can not extract oxygen from capillaries
PO2 of arterial and venous blood will be same
15. Histotoxic Hypoxia
Atmospheric PO2 normal
Alveolar PO2 normal
RBC count normal
Blood flow is normal
Tissues can not use oxygen
16. Oxygen therapy
Provided to patients with hypoxia
1. Placing the patient’s head in a tent that contained
air
2. Providing the patient either pure oxygen or high
concentration of oxygen to breath from a mask
3. Administering oxygen through intra nasal tube
17. Hyperbaric Oxygen therapy
Oxygen supply at high pressures
Patients were placed in a large pressure tanks and
treated with hyperbaric oxygen
The oxygen is administered at PO2 values 2-3
atmospheric pressure through a mask or intra tracheal
tube
Used in the treatment of gas gangrene infections.
Clostridial organisms grows best under anaerobic
conditions and stop growing when pressure of oxygen
increases
18. Hyperbaric Oxygen therapy
Used in the treatment of
1. Decompression sickness
2. Arterial gas embolism
3. Carbon monoxide poisoning
4. Osteomyelitis
5. Myocardial infarction
19. Where Cyanosis is seen?
Bluish discoloration of skin and mucous membrane
Increase in the concentration of reduced hemoglobin >5
grams / 100 ml of blood
It is commonly seen in (where PO2 is very low)
1. Mountain sickness
2. Cyanotic heart disease
3. COPD
4. Pulmonary edema
5. Circulatory shock
20. Where Cyanosis is not seen?
When the concentration of reduced hemoglobin <5
grams / 100 ml of blood
Cyanosis not seen in
1. Anemic hypoxia
2. Histotoxic hypoxia
3. CO poisoning (CO-Hb is in cherry red color)
21. Why cyanosis absent in anemic hypoxia?
Hemoglobin concentration in the blood is less than 5
grams/100 ml of blood in severe anemia
22. Why cyanosis absent in histotoxic
hypoxia?
HbO2 can not be converted into reduced hemoglobin
23. Asphyxia
Means both hypoxia and CO2 retention (hyper-
capnia) is present
Acute asphyxia kills the patient within few minutes
It is seen in
1. Strangulation
2. Acute upper respiratory tract obstruction
3. Drowning
4. Circulatory shock
24. Drowning
Impairment of respiration from immersion (only head
in water)/ submersion (head and body under water)
in liquid
It is a form of asphyxia
Classified two types according to type of water
1. Fresh water drowning – Lakes, pools, rivers
2. Sea water drowning - sea
26. Drowning
Individual becomes panic
Loss of normal breathing pattern
He do not want to suck water so he holds breath
Air hunger increases (desire to breath increases)
Aspiration of water
Reflex laryngeal spasm (to limit aspiration)
Hypoxemia
With in first few minutes
27. Salt water Drowning
Aspiration of salt water
Salt water in alveoli
More electrolytes in alveoli
Less electrolytes in capillary
Movement of water from capillaries to alveoli
Pulmonary edema
28. fresh water Drowning
Aspiration of fresh water
Fresh water in alveoli
Less electrolytes in alveoli
More electrolytes in capillary
Movement of water from alveoli to capillaries
Hemodilution
29. Dirty water Drowning
Aspiration of Dirty water
Dirty water in alveoli
Aspiration of bacteria
Diseases like pneumonia may occurs
30. Aspiration in Drowning
Aspiration of water is less important
One can aspire 3-4 ml/kg
Because of reflex laryngeal spasm
So most of the water goes to stomach
31. Pulmonary effects of Drowning
Washing out of surfactant
Collapse of alveoli
V/P mismatch
No oxygenation of blood
hypoxemia
Hemodilution
32. Neurological effects of Drowning
hypoxemia
Cerebral edema
Increase in intra cranial pressure
Ischemia of brain
Neuronal damage
33. Cardiovascular and renal effects of
Drowning
Arrhythmias – Fibrillation of atria
Hemoglobinuria
Myoglobinuria
35. Emergency room
A- Airway (intubation)
B- Breathing (supplements of O2)
C- Circulation ( monitor BP, Pulse Po2 etc.)
D- Disability (Diuretics if Increased ICP)
E- Exposure ( remove wet clothes and re warm)
36. Abnormalities in regulation of respiration
1. Respiratory center depression
Old age
Anesthetics
2. Periodic breathing:
It consists of alternate waxing and waning of
respiration or alternate hyper apnea and apnea.
37. Types of Periodic breathing are:
a) Voluntary hyperventilation
b) Cheyne-Stokes respiration
c) Biot’s Breathing.