MEDICINE AND PHYSIOLOGY IN UNUSUAL ENVIRONMENT

2. MEDICINE AND PHYSIOLOGY IN UNUSUAL ENVIRONMENT • Mountain Medicine • Under-Water Medicine • Medicine on Exposure to Extremes of Temperature • Space and Aviation Medicine

3. DEEP-SEA DIVING PHYSIOLOGY • SUB AQUATIC MEDICINE • UNDER-WATER MEDICINE

4. CASE A sailer dived in the sea upto about 100 feet depth. When he came back to the surface of sea, he was exhausted, complained of severe pain and swelling of joints [esp knee and ankle joints] and hardly could move those. Some skin rashes were visible with severe itch. He was a bit drowsy and disoriented.

5. OBJECTIVE “To have safe diving“ To Learn:- • Orientation Under-Water • Pathophysiology of Under-Water Medicine • Medical Problems [Disorders] of Deep-Sea Diving • Decompression Sickness • Uses of Hyperbaric Oxygen Therapy

6. USES OF DEEP SEA DIVING • RECREATIONAL • OIL & SALVAGE • COMBAT

7. ORIENTATION UNDER WATER • VISION • HEARING • EQUILIBRIUM • RULES FOR DIVING

8. EFFECT OF SEA DEPTH ON PRESSURE AND ON GAS VOLUMES Depth (feet) Atmosphere (s) Sea level 1 33 2 66 3 100 4 133 5 166 6 200 7 300 10 400 13 500 16

9. FACTORS AFFECTING IN DIVING • Total Pressure [Depth] • Duration of Dive • Activity of Diver • Temp of Water • Drugs within body • Gas Mixtures • Rate of Descent/ Ascent

10. EFFECTS OF DIVING HEMATOLOGICAL • Hct • Platelets • DLC • TLC • Diuresis • Weight Loss • Rise in NH4

11. RESPIRATION • CO2 Retention • Dyspnoea • Ventilation

12. CVS • Arrhythmias • Hypertrophy • Cardiac Contractility • R.V. Overload

13. RENAL • Diuresis • Resp Acidosis

14. NEURAL • Disturbed mental and motor functions • Loss of Long-term memory

15. HORMONAL • Nor-epinephrine • Epinephrine • Dopamine

16. PATHOPHYSIOLOGY OF UNDER-WATER MEDICINE • BAROMETRIC PRESSURE • VOLUME OF GASES • INTRA-THORACIC PRESSURE • INTRA-ALVEOLAR PRESSURE

17. PATHOPHYSIOLOGY

18. MEDICAL PROBLEMS OF DEEP-SEA DIVING • Oxygen Toxicity • Lung damage • Convulsions Problems on Descent • HPNS • Tremors • Somnolence • CO2 Toxicity • Initial excitation and later depression of respiration • Respiratory acidosis • Lethargy • Narcosis

19. MEDICAL PROBLEMS OF DEEP-SEA DIVING • Nitrogen Narcosis • Euphoria • Impaired performance • Anesthetic effects Problems on Descent • Ear & Sinus Barotraumas

20. MEDICAL PROBLEMS OF DEEP-SEA DIVING • Decompression Sickness • Air Embolism Problems on Ascent

21. DECOMPRESSION SICKNESS OR BENDS OR HYPER-BARISM OR DIVER’S PARALYSIS

22. HISTORY 1670 : Boyles described “Decompression” 1830 : Cochrane used compressed air in tunnels and Caissons 1937 : Behnk – discovered “N2 Narcosis”

23. DECOMPRESSION SICKNESS • Pathophysiology • Resp Gases at 1 ATA • Gaseous Pressures Outside / Inside Alveoli of Lungs • Decompression Sickness Sequence • Decompression Sickness Grading

24. Few Pictorial signs of DCS • Factors Influencing DCS • Treatment of DCS • Uses of Hyperbaric Therapy • Prevention of DCS

25. PARTIAL PRESSURES OF RESPIRATORY GASES AT 1 ATA

26. STP = 760 mmHg Maximum Human Tolerance = 4 – 6 ATA for 4 hours

27. PRESSURE OUTSIDE BODY Gaseous pressure both inside and outside the body, showing at left saturation of the body to high gas pressures when breathing air at a total pressure of 5000 mm Hg, and at right the great excess of intrabody pressure that is responsible for bubble formation in the tissues when the body is returned to the normal pressure of 760 mm Hg.

28. DECOMPRESSION SICKNESS SEQUENCE

29. DECOMPRESSION SICKNESS GRADING Type I [Pain only] • Limb or joint pain-dysfunction • Itch • Skin rash • Localized swelling Type II [Serious] • Central nervous system disorder • Inner ear damage • Lungs failure • Cardiac failure

30. FACTORS INFLUENCING DCS • Exertion • Physical fitness • Temperature – cold water, hot shower • Sex – females • Age • Obesity • Dehydration • Increased carbon dioxide pressures • Alcohol intake • Physical injury • Adaptation • Dive profile • Rapid and multiple ascents • Repetitive and multi-day diving • Altitude exposure

31. Skin lesions of decompression sickness. This diver, who had had an upper limb amputation, developed ‘bends’ pain in the phantom limb, and skin bends over the body. Both responded rapidly to recompression therapy. (Photograph by courtesy of Dr Ramsey Pearson)

32. Decompression sickness: skin lesions of isobaric counterdiffusion. The subject breathed a neon/oxygen mixture at 1200 feet (360 metres), while exposed to a chamber of helium/oxygen. Gross itching accompanied the intradermal bubbles. (Photograph by courtesy of Professor C. J. Lambertsen)

33. Curved and concentric lacerations of shark bite – often with teeth left in the wound. (Photograph courtesy of Dr. G. D. Campbell)

34. TREATMENT OF DECOMPRESSION SICKNESS INVOLVES IMMEDIATE RECOMPRESSION, FOLLOWED BY GRADUAL DECOMPRESSION

35. LOCALIZED PAIN IN OR AROUND A JOINT MAY SOMETIMES BE RELIEVED BY APPLICATION OF LOCAL PRESSURE, e.g FROM AN INFLATED SPHYGMOMANOMETER CUFF

36. The value of 100% oxygen, before during and after recompression • Intravascular bubbles do not develop with oxygen breathing, [especially at 2 ATA] • Denitrogenation is maximized, reducing tissue bubbles • It reverses the development and the redevelopment of DCS

37. PREVENTION • GRADED ASCENT • USE OF SCUBA • USE OF HELIUM

38. TREATMENT • HYPERBARIC OXYGEN THERAPY [RECOMPRESSION THERAPY] • SUPPORTIVE THERAPY

39. USES OF HYPERBARIC [RECOMPRESSION] THERAPY • Gas Gangrene • Decompression Sickness • Arterial Gas Embolism • Severe Burns • Myocardial Infarction • Osteomyelitis • Carbon Monoxide Poisoning

40. THANK YOU, INDEED!