Decompression Sickness

Transcription

1 Decompression Sickness Kun-Lun Huang National Defense Medical Center Undersea and Hyperbaric Medical Institute Tri-Service General Hospital Department of Undersea and Hyperbaric Medicine

2 Hazard Diving Environment 10 m 50 m 90 m 180 m O 2 O 2 toxicity Air N 2 narcosis Dark Cold Air O 2 toxicity N 2 narcosis CO 2 retention Predators Heliox HPNS DCS Air embolism 686 m 1981 Convulsion

3 Case 1 M/25, professional diving photographer Dove to 30 meters for 40 min twice a day Pain in the left elbow 1 hour after surfacing Recompression therapy Went home right after treatment without any residual symptom

4 Case 2 M/42, recreational diver Dove to 50 meters for 20 min and surfaced without stopping because out of air supply Paraplegia 30 min after surfacing Recompression therapy Stayed in the hospital for one month and discharged without sequelae

5 Decompression Sickness A disease caused by the formation of gas bubbles with tissues, which is due to supersaturation of gas dissolved in the body fluid during reduction of ambient pressure

6 N 2 N 2 N 2 N 2 N 2 N 2

7 Gas Exchange N 2 N 2 CO 2 O 2 N 2

8 Gas Uptake and Elimination Pressure, ATA Hydrostatic pressure Airway N 2 partial pressure Tissue N 2 partial pressure P t = P 0 + ( P a -P 0 ) x ( 1 - e -kt ) Time

9 Gas Diffusion in the Lungs

10 Perfusion-Limited Gas Transport

11 Gas Uptake and Elimination P t = P 0 + ( P a -P 0 ) x ( 1 - e -kt )

12 Gas Uptake and Elimination Pressure, ATA Hydrostatic pressure Airway N 2 partial pressure Tissue N 2 partial pressure P t = P 0 + ( P a -P 0 ) e -kt Time

13 Blood Flow and Fat Content Tissue Blood Flow ml/min/100 g Fat Content %dry weight Adipose Spinal cord White >75 Gray Straited m Rest Exercise Kidney P t = P 0 + ( P a -P 0 ) e -kt K = V Q S 1 v = =1/τ S 2 V

14 Gas Uptake and Elimination 3 Fast tissue Intermediate Intermediate Slow tissue Pressure, ATA 2 Supersaturation Time, min

15 Gas Bubble and Tissue Injury Muth & Shank, NEJM 342:476, 2000

16 Air Bubble-induced Tissue Injury Possible mechanism Primary effects Bubble Secondary effects Disruption Obstruction Coagulation factors Protein denaturation Complement Kinins Ischemia & Hypoxia Platelet Oxygen radicals Neutrophil Arachidonic metabolites Proteolytic enzymes Tissue damage

17 Symptoms of DCS Itching & Crutis Marmorata Bends Joint Pain & Rhabdomyelysis Skin Muscle Chokes Lung Inner ear Vertigo Cardiovascular Shock Spinal cord Paralysis Death

18 Acute DCS Type I decompression sickness Musculoskeletal pain Skin manifestations Constitutional symptoms Type II decompression sickness Lung: gas embolism or chokes CNS: paraplegia or stroke Vestibular system: vertigo Cardiovascular system: shock

19 Diagnosis of Acute DCS No objective laboratory examination available for definite diagnosis Diving history Working (diving) pattern Diving depth, bottom time, ascending, and repetition Onset of symptoms Empiric recompression as a proof of diagnosis

20 Occupations and DCS Diving fishermen Recreational divers Military divers Tunnel workers Underwater construction crews Fighter pilots

21 Spencer s s Bubble Grading

22 Spectral Analysis of Bubble Signals

23 Treatment of DCS Stablizing vital signs Recompression Adjunctive treatments Analgesics NSAIDs Corticosteroids Anticoagulants

24 Boyle s Law

25 USN Treatment Table 6A

26 USN Treatment Table 6A Compressed air Hyperbaric oxygen Depth, ft Time, min

27 Case 3 M/33, diving fisherman Type II DCS with CNS symptoms of confusion Treated with USN Table 6A without O 2 breathing Delirium and crutis marmorata after surfacing Coma and profound chock during surfacing in the second course of Table 6A treatment Endotracheal intubation and sedation and then recompression therapy Stayed in the hospital for one week

28 Diffusion of Gases (distance)

29 Gas Exchange N 2 =79% N 2 =79% P AN2 =1800 mmhg P N2 =2000 mmhg

30 Gas Exchange O 2 =100% O 2 =100% P AN2 = 0 mmhg P N2 =2000 mmhg

31 Gas Uptake and Elimination Pressure, ATA 3 2 Fast tissue Intermediate Intermediate Slow tissue Time, min

32 USN Treatment Table 6A

33 USN Treatment Table 4

34 USN Treatment Table 5

35 Case 4 M/32, recreational diver Dove to 30 meters for 40 min four times a day Epigastric fullness a few minutes after surfacing Limb weakness 5 hours later Recompression therapy Progression to paraplegia and urinary retention during HBO 2 therapy Combined high dose corticosteroid and HBO 2 Stayed in the hospital for 2 weeks and was transferred for further rehabilitation

36 Air Bubble-induced Tissue Injury Possible mechanism Primary effects Bubble Secondary effects Disruption Obstruction Coagulation factors Protein denaturation Complement Kinins Ischemia & Hypoxia Platelet Oxygen radicals Neutrophil Arachidonic metabolites Proteolytic enzymes Tissue damage

37 Treatment of DCS Stablizing vital signs Recompression Adjunctive treatments Analgesics NSAIDs Corticosteroids Anticoagulants

38 Case 5 M/56, well maker Dove for making deep well (20 to 30 meters) in the construction area for 20 + years Denied having symptoms of severe DCS Painful disability of bilateral hips for years Total hip replacement

39 Chronic DCS Dysbaric osteonecrosis CNS degeneration

40 Delayed Treatment of DCS in USA hr 4-12 hr > 24 hr < 4 hr Diving Alert Network (DAN)

41 Residual Symptoms > 12 hr > 12 hr 4-12 hr < 4 hr 4-12 hr < 4 hr Type I DCS Type II DCS Diving Alert Network (DAN)

42 Prevention from DCS Knowing your limitations Obeying the rules of diving Understanding effects of exercise Avoiding fly after diving Knowing individual susceptibility Obesity Sex De-acclimatization

43 Incidence of DCS Male Female

44 Body Compositions Male Femal Adipose Muscle

45 Body Fat and DCS No DCS Hx of DCS DCS

46 USN Air Decompression

47 USN Air Decompression

48 No Decompression Limits

49 Diving Pattern of Well Diver 0 Depth, m Time, min

50 Diving Pattern of Well Diver 0 Depth, m Time, min

51 No Decompression Limits

52 Surface Interval in Repetitive Dives

53 Residual Nitrogen in Repetitive Dives

54 USN Air Decompression

55 Surface Interval in Repetitive Dives

56 Residual Nitrogen in Repetitive Dives

57 USN Air Decompression

58 Residual Nitrogen Time (Equivalent Single Diving Time)

59

60 Thank You

61 Record of Free Diving Depth