The document discusses hypoxia, which is an abnormally reduced oxygen supply to tissues. It describes various causes of hypoxia including inadequate oxygenation, pulmonary disease, and inadequate oxygen transport. The types of hypoxia are discussed as atmospheric, hypoventilation, anemic, stagnant, and histotoxic. Hyperbaric oxygen therapy is presented as a treatment that delivers high concentrations of oxygen at increased atmospheric pressures.

1. Hypoxia
D.A. Asir John Samuel, BSc (Psy), MPT (Neuro Paed),
MAc, DYScEd, C/BLS, FAGE
Lecturer, Alva’s college of Physiotherapy,
Moodbidri
Dr.Asir John Samuel (PT)

2. Hypoxia
• An abnormally reduced O2 supply to tissue
• A pathological condition in which the body as
a whole (generalized hypoxia) or a region of
the body (regional hypoxia) is deprived of
adequate oxygen supply
Dr.Asir John Samuel (PT)

3. Causes of Hypoxia
• Inadequate oxygenation
- Deficiency of oxygen in atmosphere
- Hypoventilation (neuromuscular disorders)
• Venous-to-arterial shunts (right-left cardiac
shunts)
- Eisenmenger's syndrome
Dr.Asir John Samuel (PT)

4. Causes of Hypoxia
• Pulmonary disease
- Hypoventilation due to increased airway
resistance or decreased compliance
- Abnormal VA/Q ratio
- Diminished respiratory membrane diffusion
Dr.Asir John Samuel (PT)

5. Causes of Hypoxia
• Inadequate oxygen transport to tissues
- Anaemia or abnormal Hb
- General circulatory deficiency
- Localized circulatory deficiency
- Tissue oedema
Dr.Asir John Samuel (PT)

6. Causes of Hypoxia
• Inadequate tissue capability of using oxygen
- Poisoning of cellular oxidation enzymes
- Diminished cellular metabolic capacity for
using oxygen, because of toxicity, vitamin
deficiency or other factors
Dr.Asir John Samuel (PT)

7. Effects of Hypoxia on body
• Hypoxia, if severe
- can cause death of cells throughout the body
• In less severe degrees
- Depressed mental activity, sometimes results
in coma
- Reduced work capacity of muscles
Dr.Asir John Samuel (PT)

8. Types of Hypoxia
• Atmospheric Hypoxia (Hypoxic Hypoxia)
• Hypoventilation Hypoxia
• Anemic Hypoxia
• Stagnant or ischemic Hypoxia
• Histotoxic or cytotoxic Hypoxia
Dr.Asir John Samuel (PT)

9. Atmospheric Hypoxia (Hypoxic Hypoxia)
• An insufficient O2 supply reaches the blood
• Due to
- Decreased atmospheric PO2 at high altitudes
- Reduced alveolar ventilation
- Impaired alveolar gas exchange
Dr.Asir John Samuel (PT)

10. Hypoventilation Hypoxia
• A reduced amount of air enters the alveoli in
your lungs, resulting in hypoxia and hypercapnia
• COPD
• Scoliosis, nasal septum deformation
• Weakened respiratory muscles - motor neurone
disease
Dr.Asir John Samuel (PT)

11. Anemic Hypoxia
• Reduced O2-carrying capacity of blood
• Due to decreased total Hb or RBC
Dr.Asir John Samuel (PT)

12. Stagnant or ischemic Hypoxia
• Insufficient O2 reaches the tissue due to
reduced blood flow
• Systemic or local
Dr.Asir John Samuel (PT)

13. Histotoxic or cytotoxic Hypoxia
• Impaired utilization of O2 by the tissues
despite a sufficient supply of O2 in the
mitochondria
• Cyanide poisoning
• Cyanide (HCN) blocks oxidative cellular
metabolism by inhibiting cytochromoxidase
Dr.Asir John Samuel (PT)

14. Hyper Baric Oxygen Therapy (HBOT)
• Medical use of oxygen at a level higher than
atmospheric pressure
• Hyperbaric oxygen therapy involves breathing
pure oxygen in a pressurized room/chamber
• Raised upto 5 times
• 100% O2 is given
Dr.Asir John Samuel (PT)

15. HBOT – indications
• Atherosclerosis
• Stroke
• Peripheral vascular disease
• Diabetic ulcers
• Wound healing
• Cerebral palsy
• Brain injury
• Multiple sclerosis
• Many other disorders. Dr.Asir John Samuel (PT)

16. Hypercapnoea
• Excess carbon dioxide (CO2) in the body (> 45
mm Hg in blood)
• Associated with hypoxia
- Hypoventilation
- Circulatory deficiency
• Hypoxia caused by reduced availability of O2
Dr.Asir John Samuel (PT)

17. Hypercapnoea – Symptoms & signs
• Flushed skin
• Full pulse
• Tachypnea
• Dyspnea
• Muscle twitches
• Hand flaps
• Reduced neural activity
• Raised blood pressure
Dr.Asir John Samuel (PT)

18. Raised PCO2
• 60 to 75 mm Hg – air hunger (rapidly & deeply)
- Dyspnea
• 80 to 100 mm Hg – lethargic & semicomatose
• 120 to 150 mm Hg – anesthesia and death
Dr.Asir John Samuel (PT)

19. Dysbarism
• Decompression sickness
• Nitrogen dissolved in
body develops nitrogen
bubbles and cause minor
or serious damage
Dr.Asir John Samuel (PT)

20. Decompression sickenss
• Caisson’s disease
Dr.Asir John Samuel (PT)

21. Dysbarism -symptoms
• Blocks many blood vessels in different tissues
• At first smallest vessels then larger vessels
• Tissue ischaemia and tissue death
• Pain in joints, muscles of leg or arms
• Dizziness or collapse and unconsciousness
• Shortness of breath, pulmonary edema
Dr.Asir John Samuel (PT)

22. Acclimatization
• Acclimatization or acclimation is the process
of an individual organism adjusting to a
gradual change in its environment such as
pressure, temperature, etc
Dr.Asir John Samuel (PT)

23. Acclimatization
• Decrease in barometric pressure is the basic
cause of all hypoxia problems in high-altitude
physiology
• As barometric pressure decreases, the
atmospheric oxygen partial pressure decreases
proportionately
Dr.Asir John Samuel (PT)

24. Effects of Acclimatization
• Drowsiness
• Lassitude
• Mental and muscle fatigue
• Headache
• Nausea
• Twitchings or seizures
Dr.Asir John Samuel (PT)

25. Effects of Acclimatization
• Decreased mental proficiency
• Decreases judgment
• Memory
• Performance of discrete motor movements
Dr.Asir John Samuel (PT)