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  1. 1. HypoxiaD.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. 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. 3. Causes of Hypoxia• Inadequate oxygenation- Deficiency of oxygen in atmosphere- Hypoventilation (neuromuscular disorders)• Venous-to-arterial shunts (right-left cardiac shunts)- Eisenmengers syndrome Dr.Asir John Samuel (PT)
  4. 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. 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. 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. 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. 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. 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. 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. 11. Anemic Hypoxia• Reduced O2-carrying capacity of blood• Due to decreased total Hb or RBC Dr.Asir John Samuel (PT)
  12. 12. Stagnant or ischemic Hypoxia• Insufficient O2 reaches the tissue due to reduced blood flow• Systemic or local Dr.Asir John Samuel (PT)
  13. 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. 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. 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. 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. 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. 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. 19. Dysbarism• Decompression sickness• Nitrogen dissolved in body develops nitrogen bubbles and cause minor or serious damage Dr.Asir John Samuel (PT)
  20. 20. Decompression sickenss• Caisson’s disease Dr.Asir John Samuel (PT)
  21. 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. 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. 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. 24. Effects of Acclimatization• Drowsiness• Lassitude• Mental and muscle fatigue• Headache• Nausea• Twitchings or seizures Dr.Asir John Samuel (PT)
  25. 25. Effects of Acclimatization• Decreased mental proficiency• Decreases judgment• Memory• Performance of discrete motor movements Dr.Asir John Samuel (PT)