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第46回日本高気圧環境・潜水医学会学術総会　プロシーディング

is“WhencanIreturn todiving?”Tostandardizeourresponses, Igenerateda4-quadrantmatrix toprovideanswers to thisquestion. The foundationsfor th i s t emplate i nclude my exper iences ,collaborationwithcolleagues inunderseamedicineandthehistoricalinformationsitedabove.The LBMMC Guidelines My4-quadrantmatrixrequiresanswers to twoquestions:First,was theDCSevent deserved or underserved and second,is the patient asymptomatic or do residuals existafter hyperbaric oxygen recompression treatment(Table1)? Ifdeservedandasymptomatic, thedivermay return todiving after counseling including adiscussionwhytheeventoccurredandhowtopreventfutureDCSoccurrenceswithsafedivingpractices.Thepatientisadvisednottoresumedivingforatwoweekperiodinordertomitigateanyinertgas-bloodvesselendotheliumreactions.For the threeotherpermutations, return todivingisnotadvised.Ifthediverisdeterminedtoresumedivingand isasymptomatic,acomprehensivework-up including a thoroughhistoryandphysicalwithspecial emphasis on cardiac and neurologicalcomponents, aneurological consultationwithbrainandspinalcordmagneticresonance imaging,and acardiacconsultationwithacardiacstresstestandabubblestudyareobtained.Finallyatrial“dive”inahyperbaricchamberto2.8atmospheresabsolutefor60minutesbreathingairandascendingovera fiveminuteperiodoftimeisdone.If theabovestudiesarenegative, thediver is thenOK’d to resumediving using conservative divingpractices.Adviceincludeslimitingmaximumdepthsto60FSW,usingconservativesettingsonthedivecomputer, diving inoptimal conditions (that is, nilcurrents,warmwaterandgoodvisibility),ascendingatrateslessthanonefooteverytwoseconds,usingathreeminutereststopat15FSW,avoidingdivingwhen fatigued, dehydrated or chilled and limitingconsecutivedaysofdivingtothree.Conclusions Sensible, consistent and objectiveadv ice can be prov ided to d ivers who haveexperiencedDCSandwant to return todivingbyutilizingourLBMMC4-quadrantdecision-makingmatrix.Figure 1: Guideline for Return to Diving after an Episode of

DCSFigure 1: Guideline for Return to Diving after an Episode of DCS

Que

stion

2: D

o Re

sidu

als

Exis

t?

(after

HBO

-Rec

ompr

essi

on)

May return to diving

Return to diving not advised**

Return to diving discouraged*

Return to diving strongly disapproved

No

Yes

Question 1: Was DCS Deserved?oNseY

Legend Questions 1 and 2 must be answered before making a decision whether or not a diver returns to diving after an episode of DCS. *If a diver is determined to resume diving after an undeserved DCS “hit,” a comprehensive work-up is required (see text). **If residuals exist, exceptions aresometimes made to allow commercial divers to do sports SCUBA diving

Key DCS = Decompression sickness, HBO = Hyperbaric oxygen

Legend Questions1and2mustbeansweredbeforemakingadecisionwhetherornotadiverreturnstodivingafteranepisodeofDCS. *Ifadiver isdeterminedtoresumedivingafteranundeservedDCS“hit,”acomprehensivework-upisrequired(seetext).**Ifresidualsexist,exceptionsaresometimesmadetoallowcommercialdivers todosportsSCUBAdivingKey DCS =Decompressionsickness,HBO=Hyperbaricoxygen

ワークショップWS4-8Return to Diving after Decompression Sickness

MichaelB.StraussDepartmentofHyperbaricMedicineLongBeach

MemorialMedicalCenter

Introduction An importantquestion thatmustbeansweredafteranepisodeofdecompressionsickness(DCS) iswhen can the diver return toSCUBAdiving?Thetreatingphysicianhastheresponsibilityfor informing thediverwhen it is safe, if ever, toresumediving. Unfortunately criteria for returnto diving are not clearly established This paperdescribesatemplateIhavegeneratedthatprovidesanobjective,simpletouseguideformakingdecisionsaboutreturntodivingafteranepisodeofDCS.Historical Considerations and Basis for Our Return to Diving Recommendations Areviewhasfailed to find definitive information about returntodivingafteraDCS“hit.”Thereare,however,somehistoricalantecedentsthathavebeenusedformaking recommendations.Dr.Behnke, stated thatadiver could return todivingafteranepisodeofDCSwhenable to resume“full runningactivity.”WhileinsightfulforepisodesofDCSwithsignificantneurologicalpresentations, itdoesnotapply to themajorityofdiverswhopresentwithlesssevereDCSsymptoms.Anotherguideline thathadbeenusedby theU.S.Navywas if theU.S.NavyTreatmentTable1wassuccessfulinresolvingthediver’ssymptoms,returntodivingwaspermittedafteroneweek. IfTable2wasrequired, then twoweeksbefore returning todiving; threeweeksforTable3andfourweeksforTable4. This information isoutdated sinceNavyTreatmentTables1-4arenolongerused.AnUndersea andHyperbaricMedicine Societyworkshop in 1986 was convened to answer thequestionwhencouldacommercialdiverscouldreturntodivingafteranepisodeofpainonlyDCS.BecauseofeconomicconsiderationsandpossiblypreventionofdelayedsequelaofDCSsuchasosteonecrosisandneurologicalramifications, therecommendationwasmade thatcommercialdivers, ifadequately treatedand theirsymptoms fullyresolved, couldreturn todivingthedayafterbecomingasymptomatic. Whilethisrecommendationwasproactive ingettinghighlymotivated commercial divers“backinthewater,”itdoesnot take intoaccountnewerdecompressionscience information that itmay takedaysor evenweekstoresolvethe inertgas-vascularendotheliumreactionsthatarebelievedtooccurwithDCS.Duringthepast34years,atLongBeachMemorialMedicalCenter (LBMMC),LongBeachCalifornia,USAhas treated nearly 400 patientswithDCS.Usually the first question asked after treatment,