CGIER 30 -Barotrauma Flashcards
How does pressure change occur during diving?
deeper a swimmer goes the pressure increases for every 10m one person goes the ambient pressure increases by atm.
Why can’t we use long tube instead of scuba diving
air at 1 atm pressure out of sea inflate lungs in the atmosphere of 2 atm. One won’t be able to overcome difference in pressure. Impossible to inflate
SCUBA
Self Contained Underwater Breathing Apparatus
How does partial pressure affect the gas absorption to henry’s law
Gas (O2, N2) Solubility in tissues increases with gas partial pressure
how will partial pressure of Oxygen and Nitrogen gas change when diving according to what law?
Will experience abnormally high pO2 and pN2 (Dalton’s Law).
What causes decompression sickness. How do we prevent it?
Must ascend VERY SLOWLY.
Caused if one ascend too quickly or don’t give enough time for body to get rid of gas -
Boyles law - gas (Mostly Nitrogen) will expand as they get larger in size they can block blood vessels and can interrupt signals being passed if bubbles are in the nerves. Body won’t have enough time to expel the gas via respiration.
solution for decompression sickness
quickly administer O2 and move to re-compression chamber
how long can it take for some tissue to naturally expel the excess gas?
24 hours
Must NOT go to a plane within 24 hours - residual dissolved gas can form bubbles in parts of the body and you will be financially liable
What do Commercial Divers use
dive greater than 60m - replace nitrogen w/ inert gas e.g. helium or argon.
Helium is light and will diffusing out of your body so quickly
what was Decompression Sickness originally called
Caisson Disease
First documented case of Decompression Sickness
pressurised container used to drive water out - people would work and dig in high pressure environment
Where else is there a risk of Decompression Sickness
During spacewalks in astronauts
Suits work at one third of Atmospheric Pressure - must slowly decompress to 1/3 of atm
Why not just replace all the N2 with oxygen while diving?
O2 becomes toxic for any pO2 greater than 1.6 atm. Results in convulsions, usually fatal underwater.
Nitrogen Narcosis
seen in around of 25 m and higher
when partial pressure is greater than 3.2 atm - has intoxicating effect
who are most susceptible to nitrogen narcosis
novice divers
what does nitrogen narcosis cause
loss of motor function and deterioration in decision making ability
Why should we NOT hold our breath as we head to the surface of the lung
lungs have not adapted to low pressure as you have not inhaled. Lungs will rupture - Boyle’s law
Sinus squeeze
gas can move to sinuses and as they move to surface the gas expands
Mask squeeze
when one forgets to equalise pressure in face mask
can result in two black eye
Disappears within a weak
shallow water blackout happens to who
snorkellers
spear fishing
free diving
shallow water blackout
limited supply of oxygen as one does not have oxygen tank - can hyperventilate using more oxygen and blowing off more pCO2. If pO2 drops below 0.1atm you can pass out
Hyperbaric therapy
Use of higher than ambient pressures to treat a variety of illnesses
hyperbaric therapy is used to treat
Radiation Tissue Damage (Soft Tissue and Osteoradio-necrosis)
Gas Gangrene-anaerobic infection)
Acute Carbon monoxide poisoning
Gamow Bage
A portable hyperbaric chamber can be used to treat Altitude Sickness
