1. High Altitude & Deep Sea Diving

2. High Altitudes & Deep sea Diving
Acclimatization to High altitude
Kilimanjaro
22-Feb-19
High Altitudes & Deep sea Diving

3. High Altitudes & Deep sea Diving
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
22-Feb-19
High Altitudes & Deep sea Diving

4. High Altitudes & Deep sea Diving
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
22-Feb-19
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
22-Feb-19
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
22-Feb-19
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)* = 70 mm Hg
Note summit of Kilimanjaro
19,536 ft (5963 m)
Kilimanjaro
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

9. Effects of High Altitude on Bar Pressure & PO2
Kilimanjaro
22-Feb-19
High Altitudes & Deep sea Diving

10. Effects of High Altitude on Bar Pressure & PO2
Altitude (ft)
Pressure mm Hg
PO2 in air mm Hg
Remarks
63,000 47 10
50,313 86 18
40,000
141 30
Severe O2 lack despite use of 100% O2
33,500
190 40
¼atmos, Mt. Everest 29,028 (250mm Hg)
20,000
349 73
Danger to life unless O2 added to inspired air
18,000
380 70
½atmos, Kili 19,360 ft
10,000
523
110
>12,000 definite O2 lack
760
159
Up to 8,000 safe zone
22-Feb-19
High Altitudes & Deep sea Diving

11. High Altitude Vs PAO2, PACO2, O2sat%
22-Feb-19
High Altitudes & Deep sea Diving

12. High Altitude Vs PAO2, PACO2, O2sat%
(ft)
Bar Press (mmHg)
PO (mm Hg)
PAO2 (mm Hg)
PACO2 (mm Hg)
Art O2 Sat%
63,000 47 10 24
30,000
226 21 20
20,000
349 73 40 70
10,000
323
110 76 36 90
760
159
104 97
22-Feb-19
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
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

15. Effect Of Breathing Pure O2
Breathing Air
Breathing 100% O2
Altitude Barr pressure
PAO2 mm Hg
% Sat
30,000 21 30
139 99
40,000 12 15 58 87
22-Feb-19
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
22-Feb-19
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
22-Feb-19
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
22-Feb-19
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
22-Feb-19
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
22-Feb-19
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
22-Feb-19
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%
22-Feb-19
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
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

25. High Altitudes & Deep sea Diving
Acclimatization
Increased capillary density
↑ the number of capillaries
↓ the distance between capillary & cells
22-Feb-19
High Altitudes & Deep sea Diving

26. High Altitudes & Deep sea Diving
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
22-Feb-19
High Altitudes & Deep sea Diving

27. Acclimatization: Cellular level
Enzymes adaptation to hypoxia
Increase number of mitochondria
Increase in cellular oxidative enzymes
22-Feb-19
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
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

30. Deep Sea diving

31. High Altitudes & Deep sea Diving
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
22-Feb-19
High Altitudes & Deep sea Diving

32. High Altitudes & Deep sea Diving
Physiologic effects
A person 33 ft beneath the ocean
Exposed to pressure of 2 atmospheres
22-Feb-19
High Altitudes & Deep sea Diving

33. Effects of Depth on pressure
Sea depth (ft)
Pressure (atmos) 1 33 2 66 3
100 4
200 7
400 13
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

35. High Altitudes & Deep sea Diving
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
22-Feb-19
High Altitudes & Deep sea Diving

36. High Altitudes & Deep sea Diving
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
22-Feb-19
High Altitudes & Deep sea Diving

37. High Altitudes & Deep sea Diving
Nitrogen Narcosis
At 150 – 200 ft
Becomes drowsy
At 200 – 250 ft
Diver usually becomes useless
22-Feb-19
High Altitudes & Deep sea Diving

38. High Altitudes & Deep sea Diving
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
22-Feb-19
High Altitudes & Deep sea Diving

39. High Altitudes & Deep sea Diving
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
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

41. High Altitudes & Deep sea Diving
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)
22-Feb-19
High Altitudes & Deep sea Diving

42. High Altitudes & Deep sea Diving
Oxygen Poisoning
At normal tissue PO2
Small amount of free radicals are formed
Body contain enzymes that remove them
Peroxidases, catalases, superoxide dismutase
22-Feb-19
High Altitudes & Deep sea Diving

43. High Altitudes & Deep sea Diving
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 
22-Feb-19
High Altitudes & Deep sea Diving

44. High Altitudes & Deep sea Diving
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
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

46. Nitrogen Dissolved in Body Fluid
Depth in ft
Amount in Liters 1 33 2
100 4
200 7
300 10
22-Feb-19
High Altitudes & Deep sea Diving

47. Decompression Sickness
Also known as
Bends
Compressed air sickness
Caisson’s disease
Diver’s paralysis
Dysbarism
22-Feb-19
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
22-Feb-19
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
22-Feb-19
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
22-Feb-19
High Altitudes & Deep sea Diving

51. Decompression Procedures
However,
If the diver is brought to surface slowly
Dissolved N2 is eliminated through the lung
Rapidly enough to prevent decompression sickness
About 2/3rd of the total nitrogen is liberated in 1 hr
And about 90% of the total in 6 hrs
22-Feb-19
High Altitudes & Deep sea Diving

52. Decompression Procedures
There are special time schedules
For decompression
Depending on the depth and duration of the dive
22-Feb-19
High Altitudes & Deep sea Diving