MEDICAL SUPPORTCONSIDERATIONS FOR MIXED GAS DIVING AT WARMMINERAL SPRINGSARCHAEOLOGICAL RESEARCH PROJECT William ikpper, MD. FamilyPractice of Tallahassee,FL 1885 Professional Park Circle, Suite 30 Tallahassee,FLORIDA 32308 U. S.A. Thispaper will describe the necessary medical support for theunderwater ar- chaeologicalstudies in thedeep portion of WarmMineral Springs, including considerationsfortreatment ofaccidents, prevention ofaccidents bydecornpressirig ongas mixtures other than air, monitoring forpossible venous gas emboli with dopplertechruque and utilization of "Tnmix" air-helium mixed gases for more effectivedeep water diving by decreasing risksof inert gas narcosis aswell as increasingbottom time available. Thisinfonnation maybe employed asa template forother deep water greater than 130 feet! scientific dive projects which can be managedbysimilar support considerations. Itisoffered aspart of a seriesofpapers aboutthe Barm Mineral Springs Archaeological Research Project which in con- tinuitywilt approach the scope of utilizationof mixed gas diving in scientific research INTRODUCTION For15 years research in the unique environment of Warm Mineral Springs has been providingvaluable information from the archaeological andpaleontological remains that are wellpreserved atmultiple levels of the spring. However, a large part of this valuable material islocated indepths inexcess ofwhat is considered tobe safe for underwater research done by diverson compressed air.In 1987, the oversight ofthe Warm Mineral Springs Archaeological ResearchProject moved from Manatee Community College tothe Department ofAnthropol- ogyat Florida State University andbegan working with the Acadeinic Diving Program ADP! todevelop diving standards and procedures forthis deep site. The already well established linkbetween the ADP Medical Advisor, as well as the ongoing integration with the Dept. of Archaeologyallowed for these resources tobe applied tothe problems of the deeper diving research.What was not readily available atthe ADP systems wassignificant expertise inmixed gas other than air! diving. Therationale for theuse of mixedgas was based upon two factors. The fist wasa concernabout the risk of decompression involved with prolonged hyperbaric exposures onair. Divirrg for Science...1999 Underwaterresearch atthis site required labor-extensive longbottom-times atdepths below 1SOfsw. This resulted inincreasingly longer periods ofdecompression, oftenon exceptional exposuretables, which had an unacceptable riskof decompressionsickness. The philosopIxy of theADP has been conservative withregard to therisk of exposureto decompression sickness.Forexample, forroutine air diving, we recommend using the D.C.I.E.M. Tables which arerecognized as ultra-conservative in the industry. Prior to FSU'sinvolvement in theVAum MineralSprings Archaeological Research Project WMSARP!, shallow water 02 decompres- sionhad been employed todimirush decompression risks.Moving tothe use of Nitrox oxygen fortifiedair! to increase the off-gas gradient atdeeper decompression stopsin conjunctioxx with the shallow02 stopswas an important enhancement we recommendedto lessen decompressionrisks. Breathingnitrox at deeper depths, however, looses its advantages because ofincreased risksof 02 Central Nervous System toxicity. Yet the air mixture atthese depths includes too muchnitrogen, inducing an unacceptable level of narcosis.Our secondconcern for these deeperdives and to avoid unnecessary hypothermia andexpense ofheliox!, was resolved by usinga trimixofhelium, nitrogen and oxygen. This would reduce the risk of diving accidents andallow for greater efficiency inthe precise work of underwater archaeology. Becauseofthe complexity in dealing with mixed gases, ie.decisions regarding what tablestouse, optimal gas mixtures andthe calculations involved, wereferred the expertise aMI experienceofR. W. Hamilton, Ph.D. He was able to extrapolate data from dives made to the depthsthat our researchers wouldbe making and develop tables with reasonable decompres- siontimes utilizing the trirnix, nitrox, and in water 02 decompression gases.Since decompres- sionsickness hasbeen described as,at least inpart, a statisticalevent, and because ofthe many variablesinvolved, doppler monitoring of ourresearch divers was included as a checkof our proceduresand as an indicator of thereliability of ourtables. Theaddition ofan on site fully operational double lock multiplace recompressioa chamberfor treatment ofpossible diving accident was integral to ourplans to insure diver safetyshould decompression symptoms appear. Inorder to fully support the chamber it was necessaryforthe Program Physician author! tobecome acquainted with the operations of recornpressionchambers andbecome qualified intheir use to treat diving accidents. %here arequite a fewprograms around thecountry where Hyperbaric Medicine istaught. The bm weekduration program taught by N.O.A.A. and the military programs of Navy & AirForce tendto bethe most inclusive. 'Were are other programs which concentrate onthe use of HyperbaricOxygen forMedical reasons. Wechoose theweek long course taught byformer NOAAinstructor Dick Rutkowski atHyperbaric International, because ofits emphasis with handson use of a fullyoperational double lock multiplace chamber and its concentration on treatingdiving related maladies. Both the Program Physician and the Assistant Director of theADP attended theclass sothat our direction ofthe chamber operator anddive supervisor wouldbe more rneaningfuL Thisalso provided theADP & WMSARPwitha personwhowas capableof operatingthe chamber should that be needed in thefuture. 226 Kepper;Medical Support for MixedGas Diving at SWS Choiceof a chamberoperator-dive supervisor was done by a combinedeffort of the managementsofWarm Mineral Springs Archaeological Research Project and the ADP. An agreementwasreached aspart of total plan of how the dive supervisor would interact with thechief scientist and his relationship with the ADP! that allowed adequate communication betweenallparties without undue interference withthe research effort. In order to enhance communication,andto develop proper procedures forthe scope of the project, an on-site visit wasmade by the Program Physician tofamiliarize himself with the dive site, support facilities, theoperation of the chamber and to consultwith the chief scientist aswell as the dive supervisor, Partof the purpose ofthe on site visit was to develop a Medical Plan for WMSARP to beused in evaluationand treatment of potentialdiving mishaps. The contents of thestandard ADPfirst aid kit andrelated equipment were augmented with the addition of stethoscopes, sphygmomanometer bloodpressure cuff!, reflex hanirner, and a positivepressure, resus- citator.Attempts were made to enlistthe local E.M.S, as a secondaryassist to our initial handlingofdiving related injury. This would allow further treatment tobe initiated such as intravenousfluid administrationand respiratory assist during recompression of a diver. Furtherrefinement of the medicalplan continued in Tallahasseeover a periodof severalmonths. Decisions regarding access to thechamber by thepublic, procedures for precautionarytreatments, return towork policies, etc.were debated extensively before a final draftwas agreed upon. The final document was drafted by Mrs. Barbara O'Horo Benton, managerof theWMSARP, and is included as appendix 1. An integralpart of theMedical Plan was the development of an evaluation and emergencynetwork system which could be activated bythe Diving Supervisor. Alldivers undergodoppler evaluations atset intervals after their dives. In an attempt to quantifyany intravascularbubbles that were detected by the Diving Supervisor, we hoped by early treat- rnenteither by 100 % oxygenatthe surface ora precautionarychamber treatment Table 5 USN!to avoid the occurrence ofan injury and delay of on-going research due to the injury. Theplan also included allowing the scientist who ascended without symptoms ofDCS or with complaintoffatigue torequest a precautionary treatment if he/she felt it appropriate00 1o 02 or a runin thechamber!. The 100go 02 wouMhave to becontinued for at least1/2 hour if begun,and the diver would be monitored forsigns and symptoms ofDCS and for bubble formationwith the doppler. If diagnosisofDCS was not made at this time, the treatment is recordedwithout penalizingthe researcher. Themedical plan addressed theintricacies ofimmediately notifying the needed per- sonnelshould an incident occur, in spiteof theremote location of theresearch site. It was decidedthat rapid transmission ofwritten, and printed material to and from the dive site was bestserved by a "facsimile"machine. This permitted dive statistics and the diver's condition, nowreduced toa reportsheet, to be communicated taFSU's ADP where it couldbe walked to Dr. Kepperand other FSU administrative offices! as well transmitted by FAXto our cortsultantDr. Hamilton for his input. The program physicians' horne, office and voice beeper numberwere all includedin themedical plan in orderto beable to expeditegetting the most Divingfor Science...1990 immediatecontact. Dr. James Lowenhertz ofMercy Hospital's Hyperbaric Unit in Mami was contactedand agreedto serveas our backupphysician and referral center. A decisionwas made by FSU in conjurictionwith the office of EnviromnentalHealth & Safety!to restrict the hyperbaric chamber usage to theneeds of thediving program only. TMsdecision was made in light of the recognition that the chamber facility was expressly designedto carefor