Pearl Producers Association

1. Pearl Producers Association Pearl Diver Induction Presented by MIK BURTON PPA Safety and Training Officer

2. Course Content • History of Diving • The Physics of Diving • Barotraumas (Pressure Injuries) • Gas Toxicity • Alcohol, Drugs & Diving • Western Australian Pearling Act • Divers Code of Practice • Golden Rules • Dive Tables and Profiles • Decompression Sickness-DCS • Chamber, Dive Dinghy Inspection • Irukandji, Saltwater Aspiration • Regulator Parts & Maintenance • Hypothermia & Shock • Pony Bottles • Written Assessment & In Water Drills • Issue PPA Induction Card

3. Historians are unable to identify the first divers.It is believed they may have been used in Naval battles as long ago as 1800 BC.The earliest recorded use of “Surface Supplied” diving is by the Romans in 77AD.Sketches of simple diving apparatus have been found in documents from around 1500.Diving Bells have been used successfully since the 17th century with hard hat diving used from around 1800

4. History of Pearl Diving Mother of Pearl has been collected by indigenous Australians over thousands of years for food and ceremonial purposes. In the early 1860’s the collection of MOP was commercialised and utalised beach combing at low tide and free-diving for shell to depths of around 40 foot. Hard hat style diving commenced out of Broome in the 1880’s with the use of hand driven air pumps. These hand pumps were replaced by engine driven pumps from 1912 onwards. The use of a motorised air supply enabled divers to descend to much greater depths for much longer dives and as a consequence there was a large increase in the number and severity of cases of the bends. Many deaths and cases of permanent weakness or partial paralysis are recorded from around 1912 onwards and the Japanese Cemetery bears witness to the high numbers of divers who paid the ultimate price in the search for pearl shell. From the 1960’s to the early 1980’s there are many reported incidents of serious cases of Decompression Sickness with high numbers of Cerebral and Spinal DCS. In the 1970’s advances in diving technology saw the gradual phasing out of hard hat diving with the use of wetsuits and hookah taking over. From this period there were many problems such as break downs, Carbon Monoxide poisonings, bends, CAGE’s etc. These were mainly due to ignorance and to a degree lack of training. A number of fatalities in the early 1980’s saw the Worksafe of the time threaten the industry with closure unless it cleaned its act up. This forced the numerous companies to work together and the PPA was formed.

5. HARD HAT DIVER & GRAVE STONE

6. Developments in diver training and safety Since 1990 there have been significant improvements in Workplace safety for divers employed in the Pearling Industry. The Pearl Producers association created the positions of Executive Officer and Training and Safety Officer and secured the services of leading Diving Medicine Consultant Dr Wong. Dr Wong heads the research into the Industry in-water oxygen decompression profiles and lectures divers and key industry personnel on diving safety. A Divers Recompression chamber was installed at the Broome Hospital in 1991 by the PPA. The Industry’s Code of Practice was introduced into the Industry also in 1991, all companies who are members of the PPA work to this Code. The Pearl Producers Association Induction Diver training course has been formulated to train suitable people in diving techniques to be utilised in the fishing, holding and farming of pearl shell oysters. training is carried out with emphasis on the fact that the Industry carries out a unique form of professional diving.

11. The Physics of Diving We all know that the earth is surrounded by a blanket of air which is termed its ATMOSPHERE . This atmosphere is around 150 km thick and is a mixture of different gases including mainly Nitrogen (approx 79%) and Oxygen (approx 21%). In order to make calculations involving this mixture of gas easier, we will use values of 80% Nitrogen and 20% Oxygen as the make up of Air. There are also traces of other gases (such as Carbon Dioxide, Hydrogen etc), but in such small quantities that they can for the most part be ignored. All gases can be compressed as they have no definite shape or volume. This mixture of gases does in fact have a weight (which we do not notice at the earths surface) and exerts a pressure on all things. This pressure can be measured in a variety of ways. Common units of pressure are (approximately) The pressure acting on a diver at depth consists of 2 parts; The weight of the air above the water (Atmospheric Pressure) and the weight of the water (Hydrostatic Pressure). The total pressure on a submerged diver is Absolute Pressure and is usually expressed as Atmospheres Absolute or ATA. 1 ATMOSPHERE (ATM) = 10 METRES OF SEA WATER (MSW) = 33 FEET OF SEA WATER (FSW) = 34 FEET OF FRESH WATER (FFW) = 1 KILOGRAM PER SQUARE CENTIMETRE (kg/cm2 ) = 14.7 POUND PER SQUARE INCH (psi) = 1 BAR (bar) = 100 KILOPASCALS (KPa) = 760 MILLIMETRES MERCURY (mm Hg)

12. GAS LAWS The way gases behave under pressure can be understood better by the application of several Gas Laws. An understanding of these laws is essential to the diver as they directly influence many aspects of diving. Of the many laws that influence the behaviour of gas, the 3 that a diver should understand are; • BOYLE’S LAW • DALTON’S LAW • HENRY’S LAW In combination, these laws explain how diving related ailments such as Decompression Sickness (or DCS) and Barotraumas (Pressure Injuries) of the lung, ears, sinus and teeth occur. They also help the diver to understand why we employ certain techniques to help prevent these injuries. Also of interest to the diver, although not to the same degree as the above laws are; • CHARLES’ LAW • ARCHIMEDES’ LAW If these laws and their relationships to each other (even in a simplified form) are understood by the diver, the chances of suffering a dive related ailment should be reduced by such a margin as to make the possibility remote indeed.

13. BOYLE’S LAWThis law defines the relationship that exists between Pressure and Volume. It states;IF THE TEMPERATURE OF A GAS REMAINS CONSTANT, THE VOLUME OF A GIVEN MASS OF GAS WILL VARY INVERSELY WITH THE PRESSURE EXERTED UPON IT.In simple terms, for a certain weight of a gas if the pressure is increased then the volume is decreased (and vice versa) by a proportional margin as long as the temperature doesn’t alter.For example;If the pressure is doubled then the volume is halved, if the pressure is halved then the volume is doubled From this diagram we can see that the greatest change in pressure and volume occurs in the top 10 msw and of this 10 msw the biggest change is in the top 3 msw. This means that the greatest danger of a barotrauma (pressure injury) occurs close to the surface. This applies during ascent and descent. Divers encounter Boyles Law during every dive, equalizing your ears and sinuses, mask squeeze and a wetsuit loosing its buoyancy and insulating qualities are all examples of this gas law in action. Any gas space in a divers body or equipment will be compressed during descent and expanded during ascent and if this change in volume is not controlled or equalised then damage of some sort will likely occur.

14. DALTON’S LAW To calculate the Partial Pressure (Pp) of a gas we simply multiply the percentage of the gas by the Absolute Pressure (ATA) the mixture is exposed to Daltons Law is important when we consider the toxic effects of gases at depths as shown in the above table. This law explains how the Partial Pressure (Pp) of a gas changes as the pressure exerted on the mixture it is a part of is altered. It states: WITH A MIXTURE OF GASES, THE TOTAL PRESSURE EXERTED BY THE MIXTURE IS EQUAL TO THE SUM OF THE PRESSURES THAT WOULD BE EXERTED BY EACH OF THE GASES THAT MAKE UP THE MIX, IF IT ALONE OCCUPIED THE SAME VOLUME. That is the total pressure (ATA) is the sum of the Partial Pressures (Pp).

15. HENRY’S LAW 1ATA 2 ATA An example of this law in action is the bubbles which form when a bottle of soft drink is opened. CO2 is dissolved in the liquid under pressure during manufacture. This pressure is maintained by the lid & is released when it is removed. As there is less pressure over the liquid it can’t hold as much dissolved gas & the excess is released as bubbles. At 1 ATA the human body contains about 1 litre of dissolved Nitrogen & as the diver breathes air under pressure, more Nitrogen dissolves in their body. If the diver were to ascend rapidly, the excess Nitrogen may come out of solution in the form of bubbles & cause DCS. To ensure this does not happen, a diver must ascend slowly and adhere to any required decompression stops. Gas Gas Dissolved Gas Dissolved Gas This diagram shows that as the pressure is increased, more molecules of gas dissolve in the liquid This gas law describes the way a gas dissolving in a liquid is effected by changes in pressure. In regards to a diver the gas is air (particularly its Nitrogen component) and the liquid is blood. Henry’s Law states that: THE AMOUNT OF GAS THAT WILL DISSOLVE IN A GIVEN AMOUNT OF LIQUID AT A CONSTANT TEMPERATURE IS DIRECTLY PROPORTIONAL TO THE PARTIAL PRESSURE OF THE GAS WHICH IS IN CONTACT WITH THE LIQUID. In simple terms, the higher the Partial Pressure of a gas over a liquid, the more of it will dissolve in the liquid.

16. CHARLES’ LAWExplains the relationship between temperature and pressure and volume.It states that: IF THE PRESSURE OF A GAS REMAINS CONSTANT, ITS VOLUME VARIES DIRECTLY WITH ITS TEMPERATURE.So we can simplify this law to say, if a gas is compressed its volume decreases and it gets hotter. If the gas is heated and the volume is stopped from expanding, its pressure will rise.Consider, when a car tire is pumped up you can feel the tire get hot. Also if a pressurized bottle such as a SCUBA tank or aerosol can or even a tin of baked beans is heated up, the pressure will rise until most likely the container (tin, can or tank) explodes. ARCHIMEDES’ LAW Although not a gas law, this law effects a diver as it concerns buoyancy. Archimedes principal says that: ANY OBJECT WHOLLY OR PARTIALY IMMERSED IN A LIQUID WILL EXPERIENCE AN UPTHRUST EQUAL TO THE WEIGHT OF LIQUID IT DISPLACES. This explains why a vessel made of steel or concrete floats, i.e. if a ship has a weight of 10 000 kg takes up the space of 15 000 kg of water it will float. Hence if a diver weighs 78 kg but displaces 75 kg of water he will sink. When the diver has a deep breath he displaces 80 kg of water and he will float. This is why divers use weights when diving, this helps achieve neutral buoyancy which is neither floating or sinking.

17. MORE PHYSICS As well as affecting the air we breathe, the underwater environment has a marked effect upon other factors which concern the diver. Temperature and Conduction of Heat: Water is an extremely good conductor of heat and the diver needs to be aware that this can cause a continual loss of body heat during a dive. Research has shown that being cold whilst diving increases the divers susceptibility to Decompression Sickness and in severe cases Hypothermia may result. Usually water temperature decrease with depth and we suffer the added complication that the insulating qualities of a wet suit also decrease with depth as the increased pressure shrinks the minute air pockets in the suit. As a rule of thumb, it is much easier to cool down when diving than to heat up when diving. Also we need to be aware that the majority of heat loss is from the head and feet so use of thick hoods and dive socks can help to limit heat loss. In summary, the cold slows down our thinking and our reflexes, it makes manual tasks more difficult and depletes our energy. It can also increase the chances of a diver suffering DCS. A diver is better off being too warm than too cold as it is a simple exercise to flush a suit with cold water to cool off, but very hard to heat up once you are cold.

18. MORE PHYSICS 4.5m 8m 11m 19m 23m 31m RED ORANGE YELLOW GREEN BLUE GREY Glass of face mask EYES AIR WATER Apparent position Actual position Light waves Light and Colour: Is effected in 3 main ways when it travels underwater, 1) Diffusion & Turbidity; is caused by the light rays which penetrate the water becoming scattered and absorbed by impurities such as silt, algae, pollution. 2) Absorption; Just as the level of light is changed as it enters water, so is the quality . From the representation alongside, we can see that red is the first colour to be absorbed by water & this occurs at quite shallow depths. 3) Refraction; As light passes through water, glass & air before it reaches the eyes it is bent as it moves through these different materials. Therefore objects' appear 25% larger & closer underwater.

19. MORE PHYSICS Sound; Is produced by the vibration of an object which creates a pattern of moving waves of molecules in the air or water (sound waves). These waves are detected by the ear drum and are converted into electrical signals that our brain recognises as sound. Sound travels the best in a dense medium, as the more tightly packed the molecules the more efficiently they transmit the sound waves. As an example, sound does not travel at all in a vacuum, while water being quite dense is an excellent conductor of sound and sound waves travel at about 1500 metres per second underwater. This is roughly four times faster than it travels in air. Because sound travels so much faster underwater it is almost impossible for a diver to tell where a sound is coming from underwater. Divers can use this excellent sound conductivity to their advantage as groups of 3 taps or 3 bangs (signal to ascend now) is an excellent way to attract the attention of another diver even if they are not in sight. We can also bang on the deck of steel or aluminum vessels to signal to divers in the water (3 big tugs on the divers hose is also very effective).

20. BAROTRAUMAIs the name given to many diving injuries and can be simplified to being a PRESSURE INJURY of some sort. • Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding gas or liquid. • Barotrauma typically occurs to air spaces within a body when that body moves to or from a higher pressure environment, such as when a SCUBA diver, a free-diving diver or an airplane passenger ascends or descends. Boyle's law defines the relationship between the volume of the air space and the ambient pressure. • Damage occurs in the tissues around the body's air spaces because gases are compressible and the tissues are not. During increases in ambient pressure, the internal air space provides the surrounding tissues with little support to resist the higher external pressure. During decreases in ambient pressure, the higher pressure of the gas inside the air spaces causes damage to the surrounding tissues if that gas becomes trapped.

21. BAROTRAUMA Examples of organs or tissues easily damaged by barotrauma are,MIDDLE or INNER EAR PARANASAL SINUSES (sinus squeeze) LUNGS (pulmonary barotrauma)EYES (mask squeeze) SKIN (suit squeeze) BONE (bone necrosis and temporal lobe injury) TEETH (dental barotrauma)PREVENTION IS BETTER THAN CURE!!

22. BAROTRAUMAS OF THE EAR From this diagram we can see that The human ear is an extremely delicate and complex organ. It contains some of the smallest bones and muscles in the body. Oval window Semi circular canals The ear can be divided into Outer Ear (visible ear to ear drum), Middle Ear (ear drum to round and oval window) and Inner Ear (round and oval windows to auditory nerve). Sound waves cause the ear drum to vibrate & this movement is transferred to the inner ear which sends impulses to the brain, which are interpreted as sound. Round window Middle ear barotraumas occur because the middle ear is filled mainly with air, when descending or ascending (reverse squeeze) the inside & outside pressure needs to be equalized. A diver achieves this by clearing their ears. Equalising the ears is commonly achieved by swallowing or performing the valsalva manoeuvre. Inner ear barotraumas are damage to the hearing and balance organs . Failing to equalise sufficiently, can cause water pressure to bulge the eardrum to an extent that the movement of the small end bone of the ossicles can damage the oval window. More commonly this damage is transferred to the round window. If these windows are damaged, the fluid from the cochlea may leak out. Damage to the oval & round windows can also occur when divers forcefully equalise their ears and is due to increased blood pressure in the head or the sudden displacement of the ear drum. COCHLEA

23. Signs, Symptoms & Treatment of Barotraumas of the Ear • MIDDLE EAR BAROTRAUMA Signs & Symptoms; A sensation of pressure developing into a sharp, localised pain on the affected side increasing with further changes of depth. If the ear drum ruptures, the diver experiences relief from the pain and a cold feeling in the ear as water enters the middle ear. Cold water may be felt trickling down the throat and the diver will most likely experience vertigo with nausea and perhaps vomiting. In less severe cases, a diver may experience a feeling of fullness and discomfort with some pain in the ear. Sounds may appear muffled or seem to echo. Often there is a squeaking sound accompanied by some pain during equalisation. Small amounts of blood may be noticed coming from the nose or mouth after surfacing and a crackling sound may be heard when chewing or swallowing. Treatment; A diver who has experienced a middle ear barotrauma needs to be examined by a Doctor who is trained in diving medicine. To allow complete healing, flying, diving and middle ear equalisation should be avoided from 1-2 days up to 1-2 weeks. If the ear drum was perforated, healing may take as long as 3 months.

24. Signs, Symptoms & Treatment of Barotraumas of the Ear • INNER EAR BAROTRAUMA Signs & Symptoms; One or more of the following classic symptoms must be present to make this diagnosis. • Tinnitus, a buzzing or ringing sound in the ear which is usually high pitched. • Hearing loss, due to the fluid leaking out of the inner ear. • Vertigo, a feeling of rotation, rocking or unsteadiness. • Nausea and vomiting. • Dysacusis, described as painful hearing. A possible but unlikely symptom. • Fluid may be noted in the middle ear or a feeling of fullness inside the ear. Treatment; If a diver presents with any of these symptoms they require immediate assessment by a diving doctor. Ensure no medication which may thin the blood is administered (Aspirin etc). Diver should sit upright & avoid straining, sneezing, nose blowing, loud noise or any clearing of the ears.

25. SINUS BAROTRAUMA The biological role of the sinuses is debated, but a number of possible functions have been proposed: Decreasing the relative weight of the front of the skull, and especially the bones of the face. The shape of the facial bones is important, as a point of origin and insertion for the muscles of facial expression. Increasing resonance of the voice. Providing a buffer against blows to the face. Insulating sensitive structures like dental roots and eyes from rapid temperature fluctuations in the nasal cavity. Humidifying and heating of inhaled air because of slow air turnover in this region.

26. SINUS BAROTRAUMA The majority of our sinuses are connected to the nasal cavity through narrow openings (called ostium) and through these are permanently open to the atmosphere. As water pressure changes during a dive, the sinuses usually equalise automatically by the free movement of air into & out of their openings. Should these passages become blocked for some reason, as the air space is compressed during descent the decreasing volume is replaced by swelling of the sinus lining, bleeding or tissue fluid. Signs & Symptoms; During descent pressure will be felt which escalates into pain in the area of the blocked sinus (above the eye, the cheek bone or deep behind the nose). The pain generally settles during the dive but often develops as a dull headache post dive. Small amounts of blood from the nose after ascent is common. Treatment; If a diver suspects a sinus barotrauma & has a persistent headache after diving, they should have a proper medical assessment. This is essential as many diving ailments can present with a headache as the predominate symptom. Increasing pain & fever after diving may indicate an infection & doctors may prescribe antibiotics & decongestants. Excessive bleeding into the sinus cavity may be cleared with oral & nasal decongestants. Flying or diving to be avoided until condition has cleared, usually around 2-10 days.

27. PULMONARY BAROTRAUMA (LUNG PRESSURE INJURY) Commonly referred to as a BURST LUNG this second only to drowning as a cause of death in divers. Due to Boyle’s Law we know that air will expand as a diver ascends. If this ascent is controlled & the diver breathes normally, this expanding air is expelled without any effort from the diver. There is enough pressure change in as little as 1.5 msw to burst a lung. Common causes of a Burst lung; • BREATH HOLDING DURING ASCENT. • AIR TRAPPING IN THE LUNG. • DISORDERS OF THE LUNG CAUSING STIFFNESS. • RAPID ASCENTS. • EMERGENCY OR FREE ASCENTS. • BUDDY BREATHING, ESPECIALLY DURING ASCENT. If an emergency ascent is conducted a diver should make a continual sound during the ascent to ensure excess pressure is vented from the lungs.

28. PULMONARY BAROTRAUMA (LUNG PRESSURE INJURY) SIMPLIFIED DIAGRAM SHOWING THE 3 TYPES OF LUNG PRESSURE INJURIES PNEUMOTHORAX Air in the chest cavity EMBOLISM (CAGE) Air bubbles in the blood EMPHYSEMA Air bubbles in the tissues

29. PULMONARY BAROTRAUMA If the lungs are over stretched or rupture due to a build up of excessive pressure, severe damage to the lung is likely. Bleeding, bruising & general damage to the lung tissue will cause severe breathing difficulties. Shortness of breath, chest pain, coughing, coughing up blood and shock are all common symptoms of lung damage. Any or all of the following may occur if the lungs rupture. • GAS EMBOLISM (gas bubbles in the blood). • PNEUMOTHORAX ( gas in the chest cavity). • EMPHYSEMA (gas in the tissues). A DIVER SUSPECTED OF SUFFERING A BURST LUNG REQUIRES URGENT MEDICAL ATTENTION.

30. THE HUMAN LUNGS 1: Trachea, 2: Pulmonary artery, 3: Pulmonary vein, 4: Alveolar duct, 5: Alveoli, 6: Cardiac notch, 7: Bronchioles, 8: Tertiary bronchi 9: Secondary bronchi, 10: Primary bronchi, 11: Larynx

31. GAS EMBOLISM (Gas in the Blood),AGE (arterial gas embolism), CAGE (cerebral arterial gas embolism) If the wall of an Alveoli is torn along with the capillaries contained in it, gas can be forced into the damaged capillaries and enter the bloodstream. The normal circulation of the blood may carry these bubbles to the brain, heart and other organs where the bubbles may lodge, blocking the supply of oxygen to vital organs. Signs & Symptoms; Present immediately or shortly after surfacing & may include; Unconsciousness, Fits Numbness or Tingling, Pins & Needles, Total or partial Paralysis or Weakness, Visual disturbance such as Tunnel Vision, Blank Spots, Difficulty Focusing, Speech Impairment or Slurred Speech, Loss of Balance or Un Co-ordination, Loss of Intellectual Function or Confusion, Heart Attack type symptoms such as Chest Pain, Shortness of Breath, Erratic Heart Beat, Marbling of the Skin (white or purplish blotches)

32. PNEUMOTHORAX (Gas in the Chest Cavity), If the lung wall ruptures, gas may collect between the lung itself and the internal wall of the chest (the plural cavity). Because the tissue of the lung is quite elastic, this gas pocket will cause the lung to collapse. If the damage to the lung is severe, occasionally a one way valve effect can occur whereby every breath forces more air into the plural space but will not let it return. Signs & Symptoms; In severe cases symptoms will become apparent very soon after surfacing, in milder cases the symptoms may be delayed for several hours and may only be brought on by coughing or exposure to altitude. Chest Pain, often intensified by breathing, Shortness of Breath,, Shallow Cough, perhaps with bloody sputum from mouth or nose, Increasing Heart Rate and Rate of Respiration, Windpipe may become Dislodged to the Side, Patient my become Cyanotic (blue) and Shocked.

33. EMPHYSEMA (Gas in the Tissues),May be Subcutaneous (under the skin) or Mediastinal (in the middle). This ailment occurs when gas escapes through torn Alveoli into the tissues of the lung itself and the mass of tissue in the middle of the chest cavity (the Mediastinum in the mid line). From here it may spread to under the skin at the base of the neck or, in extreme cases, into the heart sac (Pericardial Sac) or Abdominal Cavity. Signs & Symptoms; Gas in the tissues causes damage by squashing blood vessels and restricting blood flow. Compression of nerves, oesophagus, larynx and even the heart may also occur. It may take some time for the symptoms to become apparent (and they may only be slight), as the gas is slow to move through the tissues. Chest Pain, Shortness of Breath, Voice Changes, often described as the voice developing a Tinny or Brassy tone, Difficulty Swallowing, Feeling of “fullness in the Throat”. Crackling or Rice Bubbly sensation felt under the skin around the neck.

34. PULMONARY BAROTRAUMA As the range of symptoms is so large, any unusual behavior or sensations experienced by a diver upon, or immediately after, surfacing (particularly after a rapid ascent), should be regarded as a symptom of a possible burst lung and should be treated accordingly. TREATMENT Requires urgent recompression in a chamber. As none will be available on site, IN WATER RECOMPRESSION SHOULD NOT BE ATTEMPTED, all haste needs to be taken to present the diver to a chamber. During the delay the patient should not be allowed to sit or stand up; Seek URGENT MEDICAL ADVICE !! Initially patient may require standard first aid of D, R, A, B, C, D Lay the Patient on their Left Side in the Coma Position, Administer 100% oxygen, Reassure and treat for shock, Monitor and Record vital signs.

35. GAS TOXICITY AND POISONING • Of particular concern to the diver are the effects of; • OXYGEN (O2) • CARBON MONOXIDE (CO) • CARBON DIOXIDE (CO2) • NITROGEN (N2) Too much or too little of certain gases will effect the human body in many ways, with the end result generally being death to the individual concerned. As a diver breathes air at elevated Partial Pressures, any contamination of the breathing air will compounded due to the effects of DALTON’S and HENRY’S Laws. These gas laws also come into play even if the air is clean, but breathed at depth.

36. OXYGEN….Hypoxia & Oxygen Toxicity Hypoxia literally means a deficiency in oxygen & may refer to: Hypoxia (medical), a shortage of oxygen in the body. Hypoxaemia is the reduction of oxygen specifically in the blood; anoxia is when there is no O2 available at all. Ischemia, a restriction in blood supply (and therefore oxygen supply) to an organ or section of the body, generally due to constriction or blocking of blood vessels. Hypoxia (environmental) or oxygen depletion, a reduced concentration of dissolved oxygen in a water body leading to stress and death in aquatic organisms. Environmental hypobaric hypoxia, a condition at high altitudes such as mountains where the reduced partial pressure of oxygen results in hypoxia.

37. HYPOXIA Generally the individual will be unaware they are starved for Oxygen & may black out without warning, consider Shallow Water Blackouts. This makes prevention essential. If the Pp O2 remains above 1.6, Hypoxia should remain unlikely. Signs & Symptoms; • Drowsiness, confusion, lack of fine muscle control. • Cyanosis (blueness of the lips, finger tips, ear-lobes, eyelids). • Labored, uncomfortable breathing. • Possible fits & spasms leading to unconsciousness & death. Treatment; • DRABCD • 100% OXYGEN • Treat for Shock • Seek Medical Aid , Observe & Record

38. OXYGEN TOXICITY (Hyperoxia) Oxygen is essential for life, but when partial pressures are allowed to exceed the normal, damage of organs can occur, such as: • CNS Oxygen Toxicity • Pulmonary Oxygen Toxicity • Other effects: which could affect the eyes, and the haematological system. At oxygen pressures of 3 ATA (303KPa) or higher, the tolerable duration of exposure is limited by the development of CNS oxygen poisoning. While at 2 ATA (202KPa) or lower, the effects of pulmonary oxygen toxicity are usually dominant.

39. CNS Oxygen Toxicity First described by Paul Bert in 1878 (observed seizures in animals). First seizure in humans were observed by Damant & Phillips in 1933. This effect occurs only under hyperbaric conditions. Related to partial pressure of oxygen and duration of exposure. More likely to occur in the immersed than in the dry at equivalent pressures, also • individual variation • daily variation in the same individual

40. CNS OXYGEN TOXICITY This graph shows the incredible differences between different individuals regards their tolerance to exposure to breathing 100% O2 at a depth of 27 metres. From this we can deduce that different people are effected differently and have varying levels of tolerance to O2

41. CNS OXYGEN TOXICITY This graph shows the variations in tolerance to O2 experienced by the same person on different days From this we can see that the same person can be effected differently & experience different tolerances to O2 on different days

42. Factors which affect Oxygen tolerance - decrease the latent period. Exercise Increased FICO2 or Hypoventilation, (Hyperventilation - increases the latency for seizures) Immersion in water - even at rest Age - more susceptible in older subjects Fever

43. CNS Oxygen Toxicity Signs & Symptoms; (VENTID - USN) Vision disturbance - tunnel vision Ears - abnormal sounds Nausea Twitching - lips, facial muscles; tingling of the extremities Irritability Dizziness Treatment; If the warning signs of CNS Toxicity develop, the individual should breath O2 at a partial pressure less than 2 ATA until symptoms abate. If the diver is breathing 100% O2 this should be immediately substituted for AIR

44. PULMONARY OXYGEN TOXICITY Lorrain-Smith Effect Damage to the lungs in the form of pneumonitis was reported by J Lorrain-Smith in 1899. The risk occurs when O2 is breathed at Partial pressures greater than 0.5 ATA. Early changes in the lungs are reversible, but if exposure continues, permanent changes can occur and can cause death. For permanent damage to occur, exposure needs to be in excess of 16 hours. This is why we insert AIR BREAKS when using 100% O2. Signs & Symptoms; • Discomfort or Irritation deep in the chest behind the Sternum, • Progressing to pain which is made worse by breathing. • Shallow, painful cough. • Shortness of Breath with Pneumonia like symptoms (fluid on the lungs). Treatment; Symptoms will dissipate on thier own if the Pp of inspired O2 is dropped to normal (0.2 ATA). Short periods of air breathing (air breaks) will delay the onset of symptoms.

45. Other effects of OXYGEN TOXICITY Ocular effects of Oxygen Toxicity Progressive myopia - occur in some patients who receive hyperbaric treatments (20% -40% incidence - loss of 0.5 to 1 dioptre per month), more common in diabetic and elderly patients. Complete recovery usually occurs within 6 weeks (not all patients). Maturation of cataracts. This may occur in patients who receive in excess of 150 daily treatments (hood Vs mask). Retrolental fibroplasia in premature infants. Temporary visual loss in retrobulbar neuritis. Peripheral vision: progressive loss of peripheral vision to the point of almost total blindness (tunnel vision) has been reported in a man who breathed O2 at 3 ATA for 3.5 hours. Recovery almost complete within 50 mins. Haematological effects of Oxygen Toxicity RBC haemolysis (0.34-3.0ATA) Red cell mass declined significantly and continuously in men who breathed 100% O2 at 0.34 ATA for 30 days (due to haemolysis and suppression of erythropoiesis)

46. OXYGEN USAGE GUIDELINES Although the misuse of O2 can have disastrous consequences to the diver, the pearling industry has been using it for many years without incident. All divers should be aware of the benefits of O2 as an aid in washing N2 and for treatment of diving related injuries. If medical advice has determined the use of oxygen on the surface, ensure the following:- • Oxygen is to be administered at the earliest possible time, continuing until advised to discontinue this treatment by medical personnel or admission of the patient to a medical treatment facility. • Note: Oxygen is to be administered for 25 minutes, with a 5 minute air break, prior to recommencing further 25 minute administrations. [i.e. 25 minutes on Oxygen, 5 minute air break, 25 minutes on Oxygen, 5 minute air break etc.] • Area is well ventilated. • All flammable liquids (e.g. fuels and oils) carried in boat and any other combustible material is secured away from the treatment area. • Keep away from any ignition sources (e.g. compression motors to be shut down)

47. OXYGEN USAGE GUIDELINES Bottle sizes with approximate content in litres MEDICAL OXYGEN colour code, black with white top Gas bottles set up with a manifold & secured in a rack

48. CARBON MONOXIDE (CO) POISONING CO is the most common lethal contaminate of breathing air. It is an odourless, colourless gas that is produced by petrol & diesel engines & is found in cigarette smoke. The danger of CO arises from its ability to bind with haemoglobin (200 to 300 times better than O2). Breathing air contaminated with as little as 0.05% CO, will tie up around half the body’s heamoglobin. As this occurs it produces a CHERRY REDpigment called Carboxyhaemoglobin which can’t carry O2. This leads to tissue hypoxia (starving of O2) & ultimately death. During a dive the Pp of the CO is increased & the rate at which it is absorbed into the blood is also significantly increased. For example, on a 20 msw dive (3ATA), the CO will be absorbed 3 times as fast as on the surface. Therefore we can expect the onset of symptoms to be accelerated also. The pearling industry suffered 2 fatalities in the early 80’s that were attributed to Carbon Monoxide poisoning

49. CARBON MONOXIDE (CO) POISONING Signs & Symptoms 35 ppm (0.0035%) Headache and dizziness within six to eight hours of constant exposure 100 ppm (0.01%) Slight headache in two to three hours 200 ppm (0.02%) Slight headache within two to three hours 400 ppm (0.04%) Frontal headache within one to two hours 800 ppm (0.08%) Dizziness, nausea, and convulsions within 45 minutes. Insensible within two hours. 1,600 ppm (0.16%) Headache, dizziness, and nausea within 20 minutes. Death in less than two hours. 3,200 ppm (0.32%) Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes. 6,400 ppm (0.64%) Headache and dizziness in one to two minutes. Death in less than 20 minutes. 12,800 ppm (1.28%) Unconsciousness after 2-3 breaths. Death in less than three minutes.

50. CARBON MONOXIDE (CO) POISONING Signs & Symptoms; As can be seen on the previous page, the higher the contamination the faster & more severe the symptoms. The effects of elevated Pp at depth will cause even a slight contamination of the breathing air to have the effect of a much higher concentration of CO. For example; contamination of just 400 ppm (0.04%) breathed at 20 msw will have the same effect as a contamination of 1200 ppm (0.12%). Dizziness, Headache & Tightness across the Forehead & Temples. Breathlessness, Exhaustion. Confusion, Vomiting, Collapse. Flushed (Cherry Red) Lips, Cheeks, Finger Tips, Mucous Membranes. Paralysis, Unconsciousness, Coma, Death. Treatment; Remove from contaminated air & administer DRABCD if required, 100% O2, Seek Medical Aid, Monitor & Record.