1SUSPENSIONTRAUMA:ALETHALCASCADEOFEVENTSDR.NORMANWOODJune11,2012In2009,theBureauofLaborStatisticsestimatedthattherewereover212,000industrialrelatedfallsthatresultedinseriousinjury,605fatalities.Thataverages48fallsperhourifconsideringa12hourworkdayandaworkyearof365days.OccupationalSafetyandHealthAdministration(OSHA)hasstatedthatfallsaretheleadingcauseofconstructiondeathandthesecondleadingcauseofworkplaceinjuries.OSHAalsoestimatesthatthereare6000treestandrelatedinjurieseachyeartohunters.Afterasuccessfulfallstopwithafullbodyharness,apersonwillfeeltheobviouselationofstillbeingalive.Butifimmediaterecoverybacktoastandingpositionisnotpossible,anotherlessknownlethaldangermustberespondedtoveryquickly;anditiscalledSuspensionTrauma.2OSHArequiresthatasuspendedworkerberescued“Asquicklyaspossible”,presumablywithin10minutes.Theyfurtherstate,“Suspensioninafallarrestsystemcanresultinunconsciousness,followedbydeath,inlessthan30minutes”.ANSIZ359.2statesthatcontactwithasuspendedworkermustbewithin6minutes.In2009,theConsumerProductSafetyCommission(CPSC)statedinalettertotheTreestandManufacturesAssociation(TMA)thattheuseofaSuspensionReliefStrapisnotselfrescue.Thesedecisionsandrulingsarenothap-hazardlydetermined;theyarebasedon40yearsofresearchandstudiesconductedonharnesssafetyandSuspensionTrauma.In1972,duringtheSecondInternationalConferenceofMountainRescueDoctors,anAustrianreportwasdiscussedinwhich10climbershadbecomesuspendedandhadtoberescued.Somewereusingfootloopsforsuspensionreliefstraps.TheRescuestookanywherefrom30minutesto8hours.Twoclimbersdiedbeforehelparrived,threediedshortlyafterbeingrescuedandtheotherfivediedoverthenext11days.Nonehadanyexternalsignsofsignificantinjury.TheyalldiedfromSuspensionTraumabutfromdifferentmechanismsofpathophysiology,whichwillbeexplainedshortly.TheInnsbruckMountainRescueServiceinAustriadecidedtodoadditionalcirculatoryandrenaltestingafterareviewoftheAustrianReport.Theytook10experiencedrescuepersonnelandsuspendedallofthemintheirSitharnessesandfootslings(suspensionreliefstraps).Theywereinstructednottomove.Thetestwastoproceedforaminimumof30minutes.Threetestsubjectspassedoutbeforereaching30minutesandhadtoberevived.Thetestwasstoppedshortlyafter30minutesfortheotherseventestsubjects.Allofthesetestsubjectssurvivedwithoutlongterminjury.InconcludingremarksonthepapersoftheSecondInternationalConferenceofMountainRescueDoctorsitwasstatedbytheauthors;“Orthostaticshockandtypicalrespiratoryobstructionmayleadtodeathwhenhangingonarope;theprobabilityofsurvivalafterhangingtwohoursissmall;deathmayoccurduringorafterdetachmentfromtheropewhenrescued.”3In1987,attherequestofOSHA,theUnitedStateAirForceconductedextensiveharnesssuspensiontestingattheWrightPattersonAirForceBase,Ohio.Thirteentestsubjectsweregivenacomprehensivemedicalevaluationandscreeningbeforeentryintothetestgroup.Finaltestresultsshowedthatanimmobilepersonsuspendedinafullbodyharnesshasanaveragephysicaltolerancelimitof14.5minutesbeforeexhibitingpresyncopalornearfaintingsymptomsatwhichtimethetestwasterminated.Presyncopalsymptomsincludednausea,lightheadedness,peripheralvisionloss,flushingandparesthesiasoftheextremities.Therangeoftolerancelimitsfrom5to30minuteswasobservedbeforetestingwasterminated.Itwasalsonotedthatapersonsuspendedinaverticalpositionisindangerofbraindamageandeventualdeathwithin4to6minutesoffainting.In1997,NA...
