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High Altitude & Deep Sea Diving

High Altitude & Deep Sea Diving. Acclimatization to High altitude. Kilimanjaro. High altitudes. Over 40 million people in the world Live and work at terrestrial elevations between 10,000 ft and 18,000 ft Theses ranges are considered High altitudes. Kilimanjaro. High altitudes.

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High Altitude & Deep Sea Diving

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  1. High Altitude & Deep Sea Diving

  2. Acclimatization to High altitude Kilimanjaro High Altitudes & Deep sea Diving

  3. High altitudes • Over 40 million people in the world • Live and work at terrestrial elevations between 10,000 ft and 18,000 ft • Theses ranges are considered • High altitudes Kilimanjaro High Altitudes & Deep sea Diving

  4. High altitudes • In the Andes and Himalayas • Natives inhabit permanent settlements • At elevations 18,000 ft above sea level • Prolonged exposure of un-acclimatized individual • Can cause death from hypoxia Kilimanjaro High Altitudes & Deep sea Diving

  5. Hypoxia of High Altitude • As one ascends to high altitudes • One encounters problems associated with • Hypoxia • ↑ Radiation • Exposure to cold Kilimanjaro High Altitudes & Deep sea Diving

  6. Hypoxia of High Altitude • Basic causes of hypoxia • As altitude increases • Barometric pressure falls • % composition of air does not change appreciably • Partial pressure of respiratory gases fall Kilimanjaro High Altitudes & Deep sea Diving

  7. Hypoxia of High Altitude • At an altitude of 18,000 ft (5,500m) • Barometric pressure is ½ normal • 380 mm Hg • PO2 of moist inspired air • (380 – 47)*0.2093 = 70 mm Hg • Note summit of Kilimanjaro • 19,536 ft (5963 m) Kilimanjaro High Altitudes & Deep sea Diving

  8. Hypoxia of High Altitude • At summit of Everest 29,028 ft • Barometric pressure = 250 mm Hg • PO2 of moist inspired gas = 43 mm Hg • At altitude of 63,000 ft • Barometric pressure = 47 mm Hg • PO2 of moist inspired gas = 0 mm Hg High Altitudes & Deep sea Diving

  9. Effects of High Altitude on Bar Pressure & PO2 Kilimanjaro High Altitudes & Deep sea Diving

  10. Effects of High Altitude on Bar Pressure & PO2 High Altitudes & Deep sea Diving

  11. High Altitude Vs PAO2, PACO2, O2sat% High Altitudes & Deep sea Diving

  12. High Altitude Vs PAO2, PACO2, O2sat% High Altitudes & Deep sea Diving

  13. Hypoxia of High Altitude • Effects of CO2 and water vapour • Even at high altitude • CO2 production is still there • Water vaporizes in alveoli • Leading to dilution of alveolar O2 concentration • PAO2 = (PB – PCO2 – 47) Kilimanjaro High Altitudes & Deep sea Diving

  14. Effect Of Breathing Pure O2 • Space that was occupied by Nitrogen • Is now occupied by oxygen • This improves the % saturation of Hb with oxygen High Altitudes & Deep sea Diving

  15. Effect Of Breathing Pure O2 High Altitudes & Deep sea Diving

  16. Effects Of Breathing Pure O2 • An aviator breathing oxygen in an un-pressurized air craft • Can ascend to far higher altitudes than one not breathing pure O2 • Limit for an un-acclimatized individual • Arterial O2 saturation of 50% • Only for a short time exposure of hypoxia High Altitudes & Deep sea Diving

  17. Effects Of Breathing Pure O2 • This occurs at an altitude of • 23,000 ft • In an un-pressurized plane % when • Individual not breathing pure oxygen • When individual is breathing pure oxygen • PAO2 remain 90% • Up to altitude of 39,000 ft • Falls to 50% at 47,000 ft High Altitudes & Deep sea Diving

  18. Effects of Acute Hypoxia • Begin at about 12,000 ft • Drowsiness, lastitude • Mental & muscle fatigue • Headaches, nausea • Euphoria • Above 18,000 ft • Muscular twitches & convulsions • Above 23,000 ft • Coma, death High Altitudes & Deep sea Diving

  19. Acclimatization: Respiration • ↑ pulmonary ventilation • Hyperventilation • Exposure to low PO2 stimulate chemoreceptors • Stimulate respiration • Leads to 65% increase in alveolar ventilation High Altitudes & Deep sea Diving

  20. Acclimatization: Respiration • This is an immediate compensation for high altitude • Makes it possible for a person to ascend thousands feet • The ↑ in alveolar ventilation decreases CO2 • ↓ PCO2 and ↑ pH • Both leads to inhibition of respiration • Tend to oppose stimulatory effect of hypoxia High Altitudes & Deep sea Diving

  21. Acclimatization: Respiration • After 2 to 5 days • Inhibition fades away • Ventilation ↑ 3 to 7 times the normal level • Active pumping of HCO3- from CSF • Cause ↓ pH in CSF • Chemoreceptors are once more stimulated High Altitudes & Deep sea Diving

  22. Acclimatization: O2 Transport • Haemoglobin • Hypoxia causes release of erythropoeitin • ↑ production of RBCs • Polycythemia • Haematocrit increases • From 40 – 45% to 60 – 65% • Hbg increase from 15gm% to 22 gm% High Altitudes & Deep sea Diving

  23. Acclimatization: O2 Transport • Total result is • ↑ in circulating Hbg • 50% to 90% more than normal • Polycythemia • Increase viscosity • However, these adaptive changes • Slow to develop • Take about 2 – 3 weeks • Become fully developed after many moths High Altitudes & Deep sea Diving

  24. Acclimatization: O2 Transport • ↓ affinity of Hbg for O2 • Effect of ↑ 2:3 DPG • Shift O2 –Hb dissociation curve to the right • Diffusion capacity of lung for O2 • 21 ml/mmHg/min • Increases up to 3 times more High Altitudes & Deep sea Diving

  25. Acclimatization • Increased capillary density • ↑ the number of capillaries • ↓ the distance between capillary & cells High Altitudes & Deep sea Diving

  26. Acclimatization • Cardiac output • Increased by 20 – 30% immediately • But after few days • Return back to normal • May fall slightly below normal after few months • There is increase in blood flow to • Muscles, heart, brain High Altitudes & Deep sea Diving

  27. Acclimatization: Cellular level • Enzymes adaptation to hypoxia • Increase number of mitochondria • Increase in cellular oxidative enzymes High Altitudes & Deep sea Diving

  28. Failure to acclimatize • Chronic mountain sickness • After remaining at high altitudes for a long time • One develops mountain sickness • Red cell mass and haematocrit • Become exceptionally high High Altitudes & Deep sea Diving

  29. Failure to acclimatize • Pulmonary arterial pressure • Become elevated more than during acclimatization • Right heart becomes greatly enlarged • Peripheral arterial pressure falls • Congestive heart failure develop High Altitudes & Deep sea Diving

  30. Deep Sea diving

  31. Physiologic effects • Relation of sea depth to pressure • A column of fresh water 34 ft (33 ft sea water) high • Exert the same pressure • As the atmosphere above earth High Altitudes & Deep sea Diving

  32. Physiologic effects • A person 33 ft beneath the ocean • Exposed to pressure of 2 atmospheres High Altitudes & Deep sea Diving

  33. Effects of Depth on pressure High Altitudes & Deep sea Diving

  34. Effects of Depth on volume of Gases • Can be derived from gas laws • P1V1 = P2V2 • Example if • At sea level • P1 = 1 atmosphere, V1 = 1liter • At 33 ft below sea level • P2 = 2 atmosphere • V2 = (P1V1)/P2 = ½ liter • The air chambers of the diver • Will be compressed High Altitudes & Deep sea Diving

  35. Nitrogen Narcosis • About 4/5th of air is nitrogen • At sea level pressure • Nitrogen has no bad effects to tissues • However, at high pressures • Nitrogen can cause varying degree of narcosis High Altitudes & Deep sea Diving

  36. Nitrogen Narcosis • When a diver remains beneath the sea • For about 1 hr breathing compressed air • At 120 ft • Begins to have symptoms of mild narcosis • Exhibits joviality • Becomes careless High Altitudes & Deep sea Diving

  37. Nitrogen Narcosis • At 150 – 200 ft • Becomes drowsy • At 200 – 250 ft • Diver usually becomes useless High Altitudes & Deep sea Diving

  38. Nitrogen Narcosis • The narcosis is due to effects of dissolved N2 • N2 diffuses freely through fat • Into nervous tissue • Alters conduction of nerve impulse • Decreases excitability • Brain function becomes impaired High Altitudes & Deep sea Diving

  39. Oxygen Toxicity • Effect of extremely high PO2 • When the PO2 increase above 100 mm Hg • Amount of dissolved O2 in water increases • The normal safe range of tissue PO2 • Is between 20 – 60 mm Hg • At higher tissue PO2 • Oxygen poisoning occurs High Altitudes & Deep sea Diving

  40. Acute Oxygen Poisoning • Due to extremely high tissue PO2 • Exposure to 4 atmospheres pressure of O2 • Partial pressure of about 3040 mm Hg will cause • Seizures (convulsion) within 30 to 60 min • They occur without warning • Likely to be lethal to the diver • Other symptoms include • Nausea, muscle twitches, dizziness, disturbances of vision, irritability High Altitudes & Deep sea Diving

  41. Oxygen Poisoning • Excessive intra cellular oxidation • Oxidizing free radicals • Molecular O2 • Active form of O2 • Oxygen free radicals • Super- oxide free radical (O2-) • Peroxide radicals (hydrogen peroxide) High Altitudes & Deep sea Diving

  42. Oxygen Poisoning • At normal tissue PO2 • Small amount of free radicals are formed • Body contain enzymes that remove them • Peroxidases, catalases, superoxide dismutase High Altitudes & Deep sea Diving

  43. Oxygen Poisoning • Above a critical level of alveolar PO2 (>2 atmospheres) • Hb – O2 buffering mechanism fail • Tissue PO2 rise tremendously • The amount of oxidizing free radicals  High Altitudes & Deep sea Diving

  44. Oxygen Poisoning • Effects of oxidizing free radicals • Oxidize polyunsaturated fatty acids • Essential components of cell membranes • Oxidize cellular enzymes • Damage cellular metabolism • Nervous tissue • Very susceptible • Lethal effect caused due to brain damage High Altitudes & Deep sea Diving

  45. Decompression of Diver • When a diver breathes compressed air for a long time • Amount of nitrogen dissolve in body fluid increase • The nitrogen dissolved in tissue • Not metabolized • Remains dissolve in tissue fluids High Altitudes & Deep sea Diving

  46. Nitrogen Dissolved in Body Fluid High Altitudes & Deep sea Diving

  47. Decompression Sickness • Also known as • Bends • Compressed air sickness • Caisson’s disease • Diver’s paralysis • Dysbarism High Altitudes & Deep sea Diving

  48. Decompression Sickness • When a diver has been beneath the sea for a long time • Large amount of nitrogen • Become dissolved in body fluids • If the diver suddenly comes to the surface • Significant amount of nitrogen bubbles • Can develop in the body fluid • These can cause some damages • This is known as decompression sickness High Altitudes & Deep sea Diving

  49. Decompression Sickness • Symptoms • Most of the symptoms are caused by • Bubbles blocking blood vessels • Air embolism • The symptoms include • Pain in joints and limb muscles • Nervous symptoms • Dizziness, paralysis, collapse High Altitudes & Deep sea Diving

  50. Decompression Sickness • The chokes caused by • Massive numbers of bubbles plugging pulmonary capillaries • Shortness of breath • Severe pulmonary edema High Altitudes & Deep sea Diving

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