自由潜水相关breath hold2014a

1、2/18/14Men sh, are sailors, or help from the boat while the women dive.Breath Hold Diving, Drowning and and the Physiology of ImmersionJake Freiberger, MD, MPH, CPH Associate Professor of Anesthesiology Duke Center for Hyperbaric MedicineDefending the Vandenbergand Environmental PhysiologyBreath Hol

2、d Diving, Drowning and and the Physiology of ImmersionJake Freiberger, MD, MPH, CPH Associate Professor of AnesthesiologyDuke Center for Hyperbaric Medicine and Environmental PhysiologySpecific Learning Objectives Explain the physiology of BH diving (what happens and how) Discuss the medical risks o

3、f BH diving Discuss the debate about nitrogen narcosis and DCS from BH divesJacques Mayol 1927-2001Nakaisodo or Cachido: 4-7 mConstant weightdives9Funado: 8-20 mVariable weightdiveBreath Hold Diving Sports Spearfishing Underwater hockey Underwater rugby Depth & time competitionsUnderwater Rugby

4、and HockeyAIDA Association Internationale pour le Developpement de lApnee Constant Weight (with ns)must swim, cannot pull on the rope 2013 Natalia Molchanova 128m 2011 Natalia Molchanova 101 Constant Weight (without ns) 2010 William Truebridge 101m 2008 Natalia Molchanova 69 No Limits Weighted rope-

5、­guided sled, Buoyant ascent with liY bag 2007 Herbert Nitsch 214m 2002 Tanya Streeter 160m+Static Apnea2008 David Blaine17:04 (O2 pre-breath)2013 Tom Sietas22:22 (O2 pre-breath)Dynamic (distance) Dynamic Apnea no fins Swim in 25m pool 2008 Kathryn Mc PHEE 151m 2008 Dave MULLINS 213m 20

6、08 Tom Sietas Dynamic Apnea with fins, often monofin Swim in 25m pool 2008 Alexey MOLCHANOV 250m 2005 Natalia MOLCHANOVA 214mBoyles Laws should limit BH depth (no additional gas supply and the human ribcage prevents complete collapse)1. Assume surface VC 6.02. Assume RV = 2L3. Boyles law (P1*V1= P2*

7、V2)4. Deeper than depth 66ft the predicted VC<RV(1ata * 6L=3ata * 2L)Boyles law P1V1=P2V2Depth Records Exceed Boyles Law LimitHerbert Nitsch 214m, 702YStreeterTanya Streeter 160m, 524YTrubridge12Response to face immersion in cold waterDive to 300m (984ft) for 30+ minHow is it Possible?What do the

8、 best athletes do to improve their performance?Techniques exploited to increase Endurance during B-H Diving Acute diving reflex response to immersion conserve O2 lung packing Automatic abdominal contents to chest alveolar blood transudationUmberto PelizariMeditating while reducing chest volume to co

9、mpensate for Boyles Laws effect on Residual Volume Chronic ­ Increase Total Lung Volume ¯ Decrease Residual Volume ¯ sensitivity to hypercapnia ­ cold tolerance (­ BMR?) ¯ sensitivity to hypoxia ?Mammalian Diving Reflex Apnea Marked peripheral vasoconstriction (preserve

10、s heart & brain) Blood shift to thoracic Bradycardia (10-20% up to 50% with training)Diving Adaptations in Weddell Seal Diving reflex Bradycardia and vasoconstriction PaO2 drops to 18 mmHg 20 L blood volume from spleen Lung Barotrauma lung collapses at 25 - 50m Blood enters tracheal lining to pr

11、event squeeze and ­ pN2Angiography of Harbor SealAir BreathingDivingBron KM, et al. Science 152:540, 1966Organ Blood Flow During Diving in Weddell SealZapol WM, et al. J Appl Physiol 47:968, 1979Heart Rate Falls in Elite Divers Bradycardia (-44% from control) signif. correlated with static BH d

12、uration in all subjects Associated with cardiac arrhythmias Supraventricular extrasystoles / ventricular extrasystoles)Lemaitre Int J Sports Med 2005Diving Response (bradycardia)Respiratory Control of Breathing & the Breakpoint Arterial chemoreceptors Pons and medulla respond to high PaCO2 &

13、 low pH Carod & aorc bodies respond to low PaO2 Arterial baroreceptors Mechanical receptors in lung and chest wall respond to lung volume & movement (Hering-­ Breuer reex) Central respiratory rhythm underlying it all even during breath hold21Unied Theory -­ Combinaon Arterial senso

14、rs (CO2 / O2) Phrenic nerves Vagus nerves Central feedback from nerves & diaphragm muscles -­ discomfort Central respiratory rhythm Conscious overlay22O2 & CO2 Stores O2 stores 1.5 L in Hb (blood), myoglobin (muscle), physical soluon, and gas (lung) Large increase by O2 inhalaon CO2 Lab

15、ile store 17 L (+ 105 L in bone) Small increases in warm water due to vasodilataon Lidle addional storage in lungs23Limiting O2 Consumption Increases Breath-Hold Time 6 L Vital Capacity Breath of Oxygen 300 ml/min Resting Oxygen Consumption um Breath-hold Time 18 min Minimum effort expended during c

16、ompetition 22:22 record O2 pre-breathe (Tom Sietas)How? HR control is critical Other relaxation techniques postulatedBreath hold break point and Diving BlackoutThe Important Role of CO21. Hypervenlaon and Hypoxia of ascent2. CO2 retenon with increased work of breathing during deep (high gas density)

17、 dives35y = 1.4022x - 64.734 R = 0.9036230252015105050556065PetCO2 (mm Hg)70Hypercapnic Venlatory Response TesngVentilation (L/min)Measured Oxygen consumption is lower in trained divers than in control divers Change in SpO2 less in trained divers - 2.8 % vs. - 5.5 % static - 6 % vs. - 10.1 % dynamic

18、 Heart rate did not change In nine BH and nine healthy Normal diversDelahoche 2005 Breath hold for 30 s and 45 sec both static & dynamic while swim underwater at 0.7 m/s Pool was 26 °C Performed at 60 % FVCBreath Hold Divers Train to develop a decreased sensitivity to elevated CO2 Differenc

19、es in tolerable peak pCO2 in trained BH divers v non- divers Immersion had no effectDelapille 2001tolerable peak pCO2 untrainedThe slope ofthe “CO2 Response Curve” is lower in trained diverstrainedLow Carb diets or warm up dives can reduce endogenous CO2 production and increase and BH Times R/Q (CO2

20、 out/O2 in) changes from 1.0 on carbohydrates to 0.7 with lipid diet Fats burned after prolonged exercise Warm up effect noted with competitive BH divers Danger of hypoxia if BH after prolonged exercise? (Lindholm)Cold Water Temperature Decreases Breath Hold times140120100806040200ConditionSterba 19

21、88Diving mammals have insulation% ControlSymptoms of Hypoxia in Competitive Breath-Hold Divers Loss of motor control (called“Samba”) Temporary blindness (color goes first) Impaired or lost consciousness Ferrigno studied 6 male divers using SpO2 & BIS (EEG)al BH duration longer in wet BHs (mean:

22、288s; range: 183 to 360s) than in dry BHs (mean: 229s; range: 200 to 290s) (diving reflex?) BIS (EEG) values decreased in middle portions of both types of BHs to values corresponding to light sedation)Max Ferrigno UHM 2005 32:4:294DryWet 35Wet 20Splenic Contraction Helps Divers Splenic contraction i

23、n 20 human volunteers 10 splenectomized no change 10 with spleens showed 6.4% hematocrit Increased break point by 30% Effect lasts for 10 mins post BH(Schagatay J Appl Physiol 2001)Boyles Laws should limit BH depth (no additional gas supply and the human ribcage prevents complete collapse)1. Assume

24、surface VC 6.02. Assume RV = 2L3. Boyles law (P1*V1= P2*V2)4. Deeper than depth 66ft the predicted VC<RV(1ata * 6L=3ata * 2L)Boyles law P1V1=P2V2SurfaceTLC9.6 L34 mswRV2.2 LImmersion Related Blood Shift Reduces Lung Volumes Intrathoracic blood volume ­ 0.7 L Hydrostatic pressure, head out im

25、mersion VC ¯ 10% RV ¯ 40% TLC / RV ­ 40%Immersion Pulmonary Edema Etiology?Pipin , Boyles Law and Extreme Blood ShiYs Frsco Ferrera “Pipin” of Cuba Elite Diver late 1990sTLC = 9.6 LRV = 2.2 L By Boyles Law, his max depth should be 34 msw (110 fsw)Squashed down to34Pipin at 133 msw 199

26、7 depth record 133 msw (431 fsw) To reach 133 msw, RV must = 0.6 L Must shiY (2.2 L -­ 0.6 L) = 1.6 L blood to lungsSurface133 mswTLC9.6 LRV*0.6 L35Gas Augmentation and Conservation Techniques in Breath-Hold Diving Lung Packing (glossopharyngeal inhalation) Gas forced / swallowed into lungs by

27、mouth and pharyngeal muscles Extra volume of gas used as oxygen store Allows for spare gas to be used for equalization Some divers fill sinuses & middle ear with saline2/18/14Glossopharyngeal Induced Changes in Lung VolumeGI= GP Inhalation / PackingNeti Pot to fill sinusesGE= GP ExhalationDiving

28、 Related Barotrauma Case (“lung packing”) Healthy 18 yo male Unable to dive with family because of equipment shortage mulple (>25)dives to 35 fsw Chest pain, voice change, shoulder crepitus aYer last ascent Diagnosis? Presents to Duke for FTD examinaon 2 months later FTD?Apnea after glossopharyng

29、eal inhalationApnea after reducing air in the lungs with glossopharyngeal exhalation39Apnea after glossopharyngeal inhalationJ Appl Physiol. 2009 Jan;106(1):284-­92. Epub 2008 Oct 30. LinksApnea after reducing Air in the lungs with glossopharyngeal exhalation4037Not Without Risks 1 Liner et al

30、from Lund looked at 19 divers in internaonal BH compeon Measured spirometry, SpO2, chest exam 6/19 had cough, substernal chest pain, hemoptysis FVC ¯ 16%, FEV1 ¯ 27%, SpO2 ¯ 11% Probable pulmonary edema / barotrauma J Appl Physiol. 2008 Apr;104(4):986-­90 Liner also described a c

31、ase of presumed AGE aYer BH dive all Sx resolved without Rx Aviat Space Environ Med 2010; 81:74-­641Lung Packing is Not Without Risks Scherhag et al suggest that longterm training may lead to pulmonaryhypertension Looked at 8 competitive apnea divers0.58 years, 26 yrs old 8.9 +/- 6.0 dives per

32、week Managed 4.5 +/- 0.96 min dives Results: 2D echo normal EKG & Doppler echocardiography revealed right ventricular strainScherhag Clin J Sport Med. 2005 Apnea diving experience was 2.5 +/-Pulmonary Case (A 27-­year-­old commercial training applicant with a history of progressive dys

33、pnea following an inial scuba-­diving training session) Your assessment of incident? dierenal diagnosis: Pulmonary overinaon syndrome: pneumomediasnum subcutaneous emphysema pneumopericardium pneumothorax? arteral gas embolism? FTD aYer pulmonary overinaon syndrome? When?Case 1 (A 27-­year

34、-­old commercial training applicant with a history of progressive dyspnea following an inial scuba-­diving training session) A chest radiograph was unrevealing. A computed tomography (CT) scan of his chest15Practice for Thoracic Blood Shifting Glossopharyngeal Exhalation Used to aid equali

35、zation at depth when lungs compressed Used to simulate depth effects of thoracic compression in shallow pool Very dangerous no margin for error for hypoxia induced loss of consciousnessHow Long Have I Been There? Exercise and hypoxia affects human ability to estimate time Time estimation during imme

36、rsion off by up to 27% Misperception of elapsed time may be a problem for long breath holdsGas partial pressure changes during a non-diving Breath-Hold (no effects from change in pressure)150Alveolar Partial 00 Pressure (mmHg) 0é PaCO2 (not PO2 ) normally causes BH breakO2safe break-­point

37、CO2030 mmHg (0.04 atm)Hypoxic Unconsciousness02040Time (sec)6080pO2< 30mm Hg causes loss of consciousnessAvailable Oxygen rises with decent and falls with ascentGas partial pressure changes during a diving Breath-Hold (effects from change in pressure)Alveolar 150ParalO2AscentPressure(mmHg) 10050D

38、escentBodomCO2unsafe break-­pointHypervenlaon lowers starngPCO2002040Time (sec)6080Diving Safety Vest (Terry Maas)50Decompression Sickness & BH Can you get the bends holding your breath? Review by Schipke 2006 of the 90 cases reported in the literature Fitz-­Clarke from Canada reviewed

39、 all breath-­ hold dives >100m -­ 192 dives reported; max depth 209m; 2 fatalies and 2 cases of DCS(UHM 2009 Mar-­Apr;36(2):83-­91)51Tuamotu Pearl Divers Diving Style in Eastern Pacic 2-­10 min hypervenlaon 30-­50 sec descent using lead weight 30-­60 sec as deep

40、 as 130 fsw 20 sec near-­panic ascent up a rope! 4-­15 min interval between dives 2-­6 hour dive day52Must assume more rapid N2 uptake than off gassingIs one breath enough N2?Is there enough N2 in a single breath?Tuamoto Divers Call it Taravana -­ “To Fall Crazily” Rapid onset wh

41、ile surfacing 47 of 235 divers (20%) aected during one 6 hr dive day 34 vergo, nausea, mental anguish 6 paral or complete paralysis 3 temporary unconsciousness (SWB?) 2 mentally aected 2 deador “someone who is "crazy because of the sea".Cross 1960 (classic paper but maybe incorrect assumpo

42、ns)53Ama Divers & DCSTaravana - “To Fall Crazily Paulev 1965 was the rstto suggestthe link between DCI and BH diving Kohshi (UHM 2005) looked at 4 professional JapaBH divers (Ama) MRI showed cerebral infarcts localized in the watershed areas of brain Local survey revealed that many Ama divers ha

43、d experienced stroke-­like events Tamaki (UHM 2010) 381 Ama divers; 12 had stroke like Sx of DCS (mostly assisted descent, Funado type) Tamaki (UHM 2010) showed brainstem infarcts on MRI in one male Ama diver54Single Breath Hold Dive and Inert Gas Narcosis? Tanya Streeter observed to benarcotiz

44、ed onat 160M N2 Kinetics (Using “Gas Man” simulation predictum PN2 at approximately 2.5 minutes PN2 brain determines anesthetic effect Alveolar gas concentration assumed to equal blood concentrationIs BH Training Good For You? Elite divers can reduce oxidative stress & lactate levels after BH Jo

45、ulia from Toulon, France Trained divers managed 440 sec at rest Controls 145 sec only Arm exercises +/- apnea / control apnea Measured ABG, Lactate, oxidants Control subjects ­ blood lactate & ­oxidative stress (TBARS, ¯ GSH & RAA ) Divers had much reduced changes in these mar

46、kers Differences became more marked after 3 month BH training programEat your anoxidant containing vegetables!Joulia Respir Physiol Neurobiol. 2002 & 2003References Andersson JP. Arterial oxygen saturaon and diving response during dynamic apneas in breath-­hold divers. Scand J Med Sci Sport

47、s. 2009 Feb;19(1):87-­91. Andersson PA. Asystole and increased serum myoglobin levels associated with packing blackout in a compeve breath-­hold diver. Clin Physiol Funct Imag 2009:29(6);458 461 Bakovic D. J Appl Physiol 95: 14601466, 2003. Spleen volume and blood ow response to repeated b

48、reath-­hold apneas Campbell EJM, Clin Sci 1967;32:42532. The eect of muscular paralysis induced by tubocurarine on the duraon and sensaon of breath-­holding. Corkey WB. UHM 1998: 25; 68. PaO2 & PaCO2 During Breath-­hold. Delahoche J. Arterial oxygen saturaon and heart rate variaon

49、 during breath-­holding: comparison between breath-­hold divers and controls. Int J Sports Med. 2005 Apr;26(3): 177-­81 Delapille P, Eur J Appl Physiol. 2001 Nov;86(1):97-­103. Venlatory responses to hypercapnia in divers and non-­divers: eects of posture and immersion. Enge

50、l GL, J Clin Invest 1946; 25, 729733. Voluntary breath holding II. The relaon of theum hold me to the oxygen tension of the inspired air. Ferrigno M. J Appl Physiol 83: 1282-­1290, 1997; Cardiovascular changes during deep breath-­hold dives in a pressure chamber. .57References Fitz-­C

51、larke JR. Risk of decompression sickness in extreme human breath-­hold diving. Undersea Hyperb Med. 2009 Mar-­Apr;36(2):83-­91. Gandevia SC, J Physiol 1993; 470, 85107. Respiratory sensaons, cardiovascular control, kinaesthesia and transcranial smulaon during paralysis in humans. Germ

52、onpré P. Passive Flooding Of Paranasal Sinuses And Middle Ears As A Method Of Equalisaon In Extreme Breath-­hold Diving. Br J Sports Med: 28 February 2008 GrossPM, J Appl Physiol 1976;41, 336340. Role of the carod bodies in the heart rate response to breath holding in man. Joulia F. Respir

53、 Physiol Neurobiol. 2002 Oct 23;133(1-­2):121-­30. Reduced oxidave stress and blood lacc acidosis in trained breath-­hold human divers. Klocke FJ J Appl Physiol 1959; 14, 689693. Breath holding aYer breathing oxygen. Kohshi K. J Occup Health 2001; 43: 5660. Neurological Diving Acciden

54、ts in JapaBreath-­Hold Divers: A Preliminary Report.58References Kohshi K. Undersea Hyperb Med. 2005 Jan-­Feb;32(1):11-­20. Neurological manifestaons in Japa Ama divers. Kohshi K. Undersea Hyperb Med. 2005 Jan-­Feb;32(1):11-­20. Neurological manifestaons in Japa Ama divers.

55、Lindholm P, Lundgren CE. J Appl Physiol. 2009 Jan;106(1):284-­92. The physiology and pathophysiology of human breath-­hold diving. Lindholm P. Eur J Appl Physiol. 2005 Aug;94(5-­6):646-­51. Studies on inspiratory and expiratory glossopharyngeal breathing in breath-­hold divers employing magnec resona