Joint Service Sub Aqua Diving Centre

1. Joint Service Sub Aqua Diving Centre DIVING ILLNESS’ & TREATMENT REVIEW

2. Objectives • Revise Basic Life Support (BLS) skills • For diving incidents: • understand the conditions • recognise signs and symptoms • understand how oxygen administration benefits these conditions • Understand appropriate equipment and the practicalities of its use • Revise oxygen administration skills • breathing casualties • non-breathing casualties

3. Outline • BLS • Medical conditions Casualty Assessment • Oxygen administration equipment • Oxygen administration in practice

5. Basic Life Support (BLS)

6. Lesson Outline • BLS skills: • Essential rescue skills • Deteriorate quickly if not frequently exercised • Advice/techniques evolve

7. Assessing the Need Indicators of the need for BLS: • no response • no chest movement • no feel of air movement

8. Priorities • D r A B C • Danger – to casualty and rescuer • Response (AVPU) • Airway • Breathing • Circulation

9. Airway blocked by tongue Head tilt/chin lift clears airway Clear airway Foreign objects Tongue

10. Priorities • Danger – to casualty and rescuer • Response • A–Alert • V– Responds to Voice • P– Responds to Pain • U–Unresponsive • Airway – clear of obstructions • Breathing– check for normal breathing (10 secs.) • Circulation– Cardiac Compressions

11. BLS: Decision Process No Unresponsive Leave casualty and get help Yes Shout for help, open up airway No Leave casualty and get help, return and give 30CCs Breathing normally? Yes • Stop to recheck only if breathing resumes, else continue until: • Qualified help arrives • Normal breathing • You are exhausted Recovery position

12. Basic Life Support (BLS) • Monitor effectiveness: • Sequence:30 compressions : 2 breaths • Rate of 100 compressions/minute • 4–5cm compression • Stop if normal breathing resumes/medical assistance arrives

13. Rescue breaths (RB) • Monitor effectiveness: • Sight • Feel • Sound • Appearance Don’t over ventilate

15. Medical Conditions

16. Oxygen Partial Pressure Scale (bar) Abilities impaired Hypoxic Hyperoxic Long term toxicity risk .08 .10 .16 .21 .5 .7 1.0 1.3 1.4 1.6 Unconsciousness Short term toxicity risk High AIR Low Inspiration default set points Oxygen Exposure • At high concentrations oxygen is toxic • PO2<0.16 bar does not support life • Need to remain within accepted oxygen exposure limits

17. Abilities impaired Hypoxic .08 .10 .16 .21 Unconsciousness AIR Hypoxia • What is it: • Lack of oxygen • PO2< 0.16 bar

18. Abilities impaired Hypoxic .08 .10 .16 .21 Unconsciousness AIR Hypoxia • Symptoms: • Inability to think clearly, confusion, sense of losing it • Loss of co-ordination • Unconsciousness, death • Primary danger is symptoms may be vague or absent • It can occur suddenly and without warning!

19. Long term toxicity risk Hyperoxic .21 .5 1.0 1.4 1.6 Short term toxicity risk AIR Hyperoxia • What is it: • Too much oxygen • Oxygen becomes toxic at elevated partial pressures • There are two different effects of Hyperoxia: • Whole Body Oxygen Toxicitywhen PO2>0.5 bar for long periods • Central Nervous System (CNS) toxicity when PO2>1.4 bar for even short periods

20. Whole Body Toxicity • Cause: long exposures to PO2>0.5 bar • Monitored to allow for recompression treatment • Physiological reactions including: • Inflammation in the lungs • Reduction in vital capacity • Congestion, oedema, bronchitis, swelling of alveolar walls, thickening of pulmonary arteries • Visual impairment • Symptoms: • Dry cough, discomfort in breathing cycle, increased breathing resistance, shortness of breath, • Severe pain, sub-sternal pain or burning • Temporary short sightedness (Hyperoxic Myopia)

21. CNS Toxicity • Also known as Acute Oxygen Toxicity • Reaction to PO2 generally > 1.4 bar • Symptoms: • CON- Convulsions • V- Vision • E- Ears, hearing disturbances • N- Nausea • T- Twitching • I- Irritability • D- Dizziness • Until convulsions begin, minor symptoms: • Can occur in ANYorder or combination • Increase in severity

22. CNS Toxicity • Convulsions • Tonic phase – do not assist • Muscles become tense • Casualty becomes rigid and holds breath • Clonic phase – do not assist • May occur seconds or minutes after the tonic phase • Casualty jerks violently (convulsion) • Depressive phase - assist • Casualty relaxes and is unconscious • Potential loss of mouthpiece • Loop flood – loss of buoyancy • Need for Basic Life Support?

23. CNS Toxicity • Convulsions • Phases can occur on surface or after PO2 is reduced (‘Off effect’) • Progressive damage to nervous system with each successive convulsion

24. Long term toxicity risk Hyperoxic .21 .5 1.0 1.4 1.6 Short term toxicity risk AIR Hyperoxia • Causes: • Inaccurate dive planning • Failure to analyse gas • Incorrect marking or fitting of cylinders

25. Long term toxicity risk Hyperoxic .21 .5 1.0 1.4 1.6 Short term toxicity risk AIR Hyperoxia • Aggravating factors • Actual PO2 • Duration of exposure • Level of exertion • Cumulative O2 exposure

26. Long term toxicity risk Hyperoxic .21 .5 1.0 1.4 1.6 Short term toxicity risk AIR Hyperoxia • Avoidance: • High PCO2 predisposes to oxygen toxicity • Accurately track your oxygen exposure

27. Monitoring Oxygen Exposure • CNS and Whole Body Toxicity need to be monitored separately • Data for both provided in BSAC Oxygen Toxicity Table • Dive planning software • Nitrox & mixed gas decompression computers

28. CO 2 Hypercapnia • What is it: • Excess CO2 in the blood • Cause: • High inspired PCO2 • Poor ventilation of diver’s lungs at depth due to increased gas density • Absorbent material exhausted in rebreathers • Channelling in absorbent material rebrerathers

29. CO 2 Hypercapnia • Symptoms • 0.03 bar PCO2 doubles breathing rate (dyspnea) • 0.06 bar PCO2 distress, confusion, lack of coordination • 0.10 bar PCO2 severe mental impairment • 0.12 bar PCO2loss of consciousness, death

30. CO 2 Hypercapnia • Further impact • Increases oxygen toxicity potential • Increases potential for DCI and narcosis • Avoidance • Meticulous preparation & monitoring of absorbent life - rebreathers • Avoiding over exertion • Resolution • Stop, slow down breathing rate, relax • Bail out to open circuit - rebreathers

31. Decompression illness (1) • Causes • inadequate elimination of nitrogen from the body during ascent • Physical damage to the alveoli due to overpressure introduces bubbles of air (emboli) into the blood Bubbles blocking blood flow Bubbles in tissues compress blood vessels Patent foramen ovale (PFO) allows bubbles to pass from venous to arterial circulation

32. Decompression Illness (2) Signs and symptoms • Denial! • Itches, rashes • Numbness, tingling, joint pains • Vision disturbances • Dizziness, nausea, headaches, confusion • Weakness, paralysis, loss of bladder/bowel control • Shortness of breath • Shock, unconsciousness • Any abnormality after a dive • Signs and symptoms appear from seconds to many hours after surfacing

33. Decompression Illness (3) On-site first aid • Lie casualty down flat • Keep casualty quiet • Administer 100% oxygen • Increased nitrogen pressure gradient assists in nitrogen elimination from bubbles in blood and tissue • The higher the percentage of oxygen the more effective – whenever possible administer 100% • Improved oxygen supply to tissues where blood flow is reduced due to bubble blockage • Treat for shock Evacuate to a recompression facility as soon as possible

34. Burst lung (1) • Cause • physical damage to lung tissue from over-extension due to over-pressurisation • Types Bubbles between organs and tissues (emphysema) Collapsed lung (pneumothorax) • Both types can occur in isolation but are usually accompanied by air embolism

35. Burst lung (2) • Signs and symptoms include • chest discomfort/pain, bloody froth • shortness of breath • changes to vocal tone, crepitation • shock • unconsciousness, death • Signs and symptoms of burst lung are frequently accompanied by those for decompression illness

36. Burst Lung (3) • Lie casualty down • Keep casualty quiet • Administer 100% oxygen • Assists in re-absorption of the nitrogen content of air in pneumothorax or emphysema • Offsets reduced effective lung surface area for gas transfer due to collapsed lung • Treat for shock • Evacuate to a recompression facility as soon as possible On-site first aid

37. Near Drowning (1) • Cause • Respiratory interruption due to fluid inhalation • Signs and symptoms • Circumstances • No breathing • Cyanosis – ashen grey / blue appearance • Weak or absent pulse

38. Near Drowning (2) • Rescue Breathing • Oxygen-enriched if possible • Concentration of oxygen reaching the casualty’s lungs during RBs is increased • Chest compressions if required • Recovery position • Evacuate to medical attention • Even if apparently fully recovered • Complications of secondary drowning On-site first aid

39. Shock (1) • Definition • inadequate circulation leading to tissue damage due to inadequate oxygenation and waste removal • Present to a greater or lesser degree in all injuries • Mechanisms • reduced blood volume (bleeding, burns, oedema) • massive dilation of blood vessels (e.g. fainting) • inadequate cardiac output (e.g. heart attack) • allergic reaction to drugs, food or stings • removal from the water after prolonged immersion

40. Shock (2) • Signs and symptoms • weakness, dizziness • pallor, sweating • rapid pulse rate • rapid breathing, feeling breathless • unconsciousness

41. Shock (3) • On-site first aid • Treat prime cause • Reassure casualty (TLC) • Keep casualty quiet • Lay casualty down with legs raised (not in the case of DCI or burst lung) • Keep warm and comfortable • Administer oxygen • Increased oxygen dissolved in the blood offsets effects of inadequate circulation • Monitor condition • Nothing by mouth (except for DCI) • Evacuate to medical attention

42. Shock (4) Immersion shock • Extreme form of blood vessel dilation due to prolonged immersion • Muscles relax due to water supporting body weight • If removed from water upright, blood can pool in lower limbs – potentially fatal • Keep casualty horizontal at all times • Discourage any movement or activity by the casualty

43. Carbon monoxide poisoning (1) • Cause • breathing gas contaminated with carbon monoxide • Effect • carbon monoxide combines about 200 times more readily with haemoglobin than does oxygen • interferes with the blood's ability to transport oxygen • may act as a cellular poison

44. Carbon monoxide poisoning (2) • Signs and symptoms • headache • pale or greyish appearance • weakness • dizziness, nausea • tunnel vision • vomiting • rapid pulse • rapid breathing • coma • convulsions

45. Carbon monoxide poisoning (3) • On-site first aid • remove casualty from contaminated breathing supply • lie casualty down with legs raised • administer 100% oxygen, or oxygen enriched Rescue Breaths, as appropriate • Benefits of 100% oxygen • more oxygen is transported in solution in the plasma • some assistance in breaking down carboxyhaemoglobin • helps restore normal cellular function

46. Summary of diving illnesses • Administration of oxygen is beneficial to the major diving disorders • 100% oxygen will provide the maximum benefit • Administer oxygen as early as possible • Oxygen is a supplement to other first aid procedures to increase their effectiveness • Casualty must always be evacuated to appropriate medical aid: • As soon as possible • Irrespective of any apparent resolution of their condition

48. Casualty Assessment

49. Incident Procedure - Front

50. Incident Procedure – Back