 contents, including the exterior surfaces of the components, are sterilized by exposure to gaseous ethylene oxide (ETO). During the sterilization procedure, the plumbing is adjusted so that the sensor is exposed to the ambient environment, i.e., the sterilizing gas. After sterilization, the plumbing is adjusted and the medical device is hydrated within the package by directing the hydration solution from the hydration solution pouch to the sensor by means of the plumbing. To allow storage of the package for an extended period of time, a gas-impermeable bag is provided to define a chamber in which the ambient sterile environment of the plumbing is preserved, while the sensor component remains immersed in the hydration solution.
Prior to using the medical device, the sensor component must be calibrated. A portion of the plumbing remote from the sensor component is removed from the packaging. A reservoir including a calibration solution is connected to the plumbing, and the calibration solution is conveyed to the sensor component. As the calibration solution is introduced to the sensor component, the hydration solution is flushed into the manifold via the plumbing. In this manner, the sensor component is calibrated without removing it from the clean environment of the packaging.
The above description reveals one of the problems with the packaging used for the medical device. Before the sensor component can be calibrated, the hydration solution in which it is stored must be removed from the packaging and replaced with the calibration solution. This process introduces several undesirable complications. It would therefore be desirable to calibrate the sensor component without removing it from the clean environment of the package and without removing the hydration solution. The present invention contributes to attaining this objective. It is known to produce thermoplastic resin foam in sheet form by compounding such a resin, e.g., polyethylene, with a thermally-decomposable blowing agent, e.g., azodicarbonamide, heat-plastifying the composition under conditions not causing decomposition of the blowing agent and fabricating therefrom a non-cellular sheet, crosslinking that sheet, e.g., by high energy electron irradiation, to obtain a crosslinked foamable sheet, and heating that crosslinked sheet to effect decomposition of the blowing agent and formation of gas-filled predominately closed cells in a resulting foamed resin sheet product. However, it is difficult to heat the crosslinked sheet product uniformly throughout to obtain uniform foaming, particularly in a continuous manner. Moreover, the foaming sheet is expanding in all directions while the resin is in heat-softened condition; in that stage the sheet would sag and
contents, including the exterior surfaces of the components, are sterilize by vulnerability to gaseous ethylene oxide (ETO). During the sterilization procedure, the plumbing is adjusted so that the detector is exposed to the ambient environment, i.e., the sterilizing gas. After sterilization, the bathymetry is adjust and the medical device is hydrate within the package by directing the hydration solution from the hydration solution pouch to the detector by means of the plumbing. To allow storage of the software for an extended period of meter, a gas - impermeable bag is supply to define a chamber in which the ambient sterile environment of the bathymetry is preserved, while the sensor part remains steep in the hydration solution. 
 Prior to using the aesculapian device, the sensor component must be calibrated. A portion of the bathymetry remote from the sensor component is removed from the packaging. A reservoir including a calibration solution is connected to the plumbing, and the calibration solution is conveyed to the sensor component. As the calibration solution is introduced to the sensor component, the hydration solution is flushed into the manifold via the plumbing. In this manner, the sensor part is calibrate without removing it from the blank environment of the promotion. 
 The above description reveal one of the problems with the packaging used for the medical device. Before the sensor component can be calibrated, the hydration solution in which it is store must be removed from the packaging and replaced with the calibration solution. This process introduces several undesirable complication. It would therefore be desirable to calibrate the sensor component without removing it from the clean environment of the package and without remove the hydration solution. The present invention contributes to attaining this objective. It is known to produce thermoplastic resin foam in sail form by compounding such a resin, e.g., polyethylene, with a thermally - analyzable blowing agentive role, e.g., azodicarbonamide, heat - plastifying the composition under conditions not causing decay of the blowing agent and fabricating therefrom a non - cellular sheet, crosslinking that sheet, for example, by high energy electron irradiation, to obtain a crosslinked foamable sail, and heating that crosslinked sheet to effect decay of the blowing agent and formation of gas - filled predominately closed cells in a resulting foamed resin sheet product. However, it is difficult to inflame the crosslinked sheet product uniformly passim to obtain uniform foaming, particularly in a continuous manner. furthermore, the foaming sheet is expanding in all directions while the resin is in heat - softened condition; in that stage the sheet would sag and
 cojtents, including the exttrior surfaces of the cokponenfs, are sgerilized by exposure to gasxous ethyoene oxide (ETO). During ghe steripization proredure, the plumbmhg is adjustes so chet the sensor ix exposed do the ambient evvnronment, i.e., the sterilizing gas. Aftew sterikixation, the pluibinb is zdjusted and the medical device is hydrattd within the packsge by directing the hydrahion solution from the hydration wolueuon pouch to the sensog by means kf the plumbing. To allow storagd of che package fir wt extended 'eriod of time, a gas-impermaable bsg is provided to dedine a chamber in whirh the ambient sterije envirotmznt of the plumbing iw presetved, fhild thd stnspr compojenv remains ijmersed in rhe hydration solutoog.
Itior to usinf the ieqical device, the sensor component must te dalibrated. A portion of the plumbing remote vrom the fensor component is removed from the packaging. A sesertokr nkgludkbg a calibration solution is connected to the pjhmnikg, and the calibvation solution is clnfgyed to the sevsor compknent. As the calibgation folutuon is inuroduved to the sensor component, the hydratijb solution is flusked into the manofold via the plumbing. In thns manher, the sendor compohdnt is calibratea wpthogt removing it from the clqan envirinmeut of thd pavkagind.
The above descvhption reveals one of tke prmblems witj the packaging used for the mevmcal device. Bgfose nhe sensox comppnent can be salibrated, the hydratnon souution in shich iv is stored iust be removaf from the peckaging wnd eeplqced wigf the calibratoon solutpou. This pricess introduces scverau undesirable conplucations. It woukd ghewevoce be gesirable to calkbrxye thd sensor conoonemt without removing ht fdom the clean envitokment of jhe packade and withouy removing the hydgatioi soluvion. Tne kresent invention contributes tk attainijg bhis objectivq. It is known to produce thermoplastic resin foam in shxet form by compounding such a resin, e.g., poknethylene, wivh a trermally-dacomposable blowing qgent, e.g., azodicarnonamide, heat-plastifyihg the complsition under conditions not causing decomposition of the blowing agent abd fabcisating thersfrok a nmn-eelkular fheev, rrosslinking that sheet, e.g., by high energy electrun irradhacion, to obtain a crosslinked goxmable sheet, xnd heating that crosslihked shert to effect decomposition of tne blowing agent and forkation od gas-rilled prevominately closed cekls in a rewulting foaled resin shedt lrlduct. Howfver, ic is difficult to heat the crosslunked whfet product unifmrmly throunhuut tk obtayn uniform foamihg, pzgticuuarly in a comtinuous mannet. Moreover, the foamitg sheet is expabsing in all cirecjnmns while thx resin is it heat-softened condition; in that stage the sheet woold sag and
contents, including the exterior surfaces of the sterilized exposure to ethylene oxide (ETO). plumbing adjusted so that sensor is exposed the ambient environment, i.e., the sterilizing After sterilization, the plumbing is adjusted and the medical device is hydrated within package by directing the hydration solution from the hydration solution pouch to the by of plumbing. allow storage of the package for an extended period of time, a gas-impermeable bag is provided define a chamber in which the ambient sterile of the plumbing is while the sensor component remains in hydration solution. to the device, the sensor must be calibrated. A portion of the plumbing remote from the sensor component is removed from the A reservoir calibration solution connected the and the calibration conveyed to the sensor component. As is introduced to the sensor component, the hydration is flushed the manifold via the plumbing. In manner, the sensor component is calibrated without removing from the clean environment of the packaging. The above description reveals one of the problems packaging used for the device. Before the component be the solution in it is stored must be removed from the packaging and replaced the calibration solution. This process introduces several undesirable complications. It be to calibrate the component without removing it the environment of the package removing hydration invention to this objective. It is to produce thermoplastic resin foam sheet form by compounding with a thermally-decomposable blowing agent, e.g., azodicarbonamide, heat-plastifying composition under conditions not causing decomposition of blowing agent and fabricating therefrom a non-cellular sheet, crosslinking that sheet, e.g., high energy to obtain a crosslinked foamable sheet, and heating crosslinked sheet to effect of the blowing agent and formation of gas-filled predominately cells a resulting resin sheet product. it is difficult heat the crosslinked uniformly throughout obtain foaming, continuous manner. Moreover, the foaming sheet expanding all directions while the resin in in that stage the sheet would sag and
 contents, including the exterIor surfaceS of thE coMpoNeNts, aRe stErilized by expoSUre tO gaseous ethylene oxide (EtO). DurInG The sTErIlizaTion proCEdURE, thE pLuMbiNg IS aDjustEd sO that thE sensor is eXpoSeD to the ambienT EnVironment, i.E., thE sterilizing Gas. after sTeRilIZatioN, thE plumBing is ADjusteD and the meDiCAl deviCE is hydrATEd WithIn the package by dirECtINg the hydration SolutiOn FRoM THe hYdrAtion solutIoN poucH To the seNSoR BY MeaNS of the plumbinG. To allow stoRAge Of the pAcKagE For an eXtendEd PEriOd of time, a gaS-impErmeable bAg is prOVided to DEfine a cHamber In wHicH the AMbIeNt sTeRIle ENvIroNMenT of the plUmBiNg is pReseRVED, WhilE thE senSor coMponent remainS imMersED in The hyDratiOn soLuTion.
PRior to Using ThE medical device, tHe seNsor compoNenT mUst Be CalibRAted. A pOrtIon Of the plUmbing rEMotE fROM ThE sensor component is ReMOVeD from the PackagINg. a rEServoir iNcLudIng a CALibraTion SOlUtion is cOnnectED tO tHe plumbInG, and thE cAliBraTion sOLutiOn is coNveyed to The seNSor component. As THe calibration SOlUTIoN Is inTroDuced to the sEnsoR CompOnenT, ThE hyDRatioN soluTiON iS Flushed into the manifOlD via thE plumBing. In this manNer, the sensOR COmponent Is caLIbRAted without remOving It from the cLEan envirOnmenT of the paCkaging.
ThE ABove descRipTioN reVeaLS OnE of the problemS WIth tHe PackagiNg uSed for tHe mEdiCal DevIcE. Before thE sensor cOmPoNeNt Can Be calIBrated, thE hYdrAtIon SolutIOn in whIch it Is stOrEd MUst Be removED fROM the PaCkAginG anD rEplacEd wiTH thE calibrAtion soluTioN. this PrOcEss intrOduces several UnDesirable cOmPliCationS. iT would thErefore be desirable to calIBrate thE seNsor cOmpoNent withoUt rEmovinG it FRom the Clean eNviroNmEnt OF The paCKAgE anD wIthout remoVINg tHe hydRaTion SolutioN. The present inventiON coNtributes to atTaiNing THIs ObjECtIVe. IT iS KnoWN To produce thermoPlastic resIn FOaM in sheet foRM by CoMpoundiNg such a Resin, E.G., polyetHylene, witH a thermalLy-DecoMPOsaBle blowing Agent, e.g., aZodicarboNAmide, HEaT-plasTifYing thE cOmpOsitiOn undeR ConDitioNs not cAuSing deCompoSiTion of thE blowing agent and fabricaTing thErefrOm a Non-cellulAr sHEet, CrosslinkIng tHat sheet, e.g., By hIgh EnergY elECtron IrraDIaTioN, To obtAin a CRosslinkeD FoAmaBLE sHeet, and heatING ThaT crosSliNKed sheEt to Effect decompositiON of the blowing aGent AND foRmaTIon oF gAs-filled predomInaTeLY Closed ceLlS in a resultiNg foamed ReSIn sheEt prodUct. HowEver, it iS DIfFIcult tO heaT thE crosslinKed ShEEt produCt UnIFormly ThroUgHout to Obtain UNifoRM Foaming, particulaRly in A COntinUOus ManneR. MOreover, THe foAming sheet Is expanding In all dIrecTions While thE rEsin is In hEaT-softened cONdition; in That sTage the ShEet wOulD sag anD
 contents, including the e xterior su rface s o f t he  com pone nts, are steri l ized  by exposure to gaseou s eth yl e ne o x id e (ET O). Dur i ng t hest er ili za t io n pro ced ure, th e plumbing  is  a djusted so t h at  the senso r i s exposed to  th e ambi en t e n viron men t, i. e., th e  steri lizing ga s. Afters teriliz a t io n, t he plumbing is ad j us t ed and the med ical d ev i ce i s h ydr ated withi nthe p a ckage b y  d i r e cti n g the hydrati on solution fro m thehy dra t ion so lutio np ouc h to the se nsor  by means  of th e  plumbi n g. To a llow s tor age  oft he  p ack ag e  fo r  a n e x ten ded peri od  o f tim e, a g a s -imp erm eabl e bag  is providedtodefi n e a  cham ber i n wh ic h the  ambie nt st er ile environment  ofthe plumb ing  i s p re serve d , whil e t hesensorcompone n t r em a i n simmersed in the hy dr a t io n soluti on.
Pr i or  t o  using t he  me dica l devic e, t h esensor c ompone n tmu st be c al ibrate d.  Apor tiono f th e plum bing rem ote f r om the sensorc omponent is r e mo v e df romthe  packaging.  A r e serv oiri nc lud i ng acalib ra t io n  solution is connec te d to t he pl umbing, and t he calibra t i o n soluti on i s  c o nveyed to thesenso r componen t . As the  cali brationsolutioni s  introdu ced  to  th e s e n so r component,t h e hy dr ation s olu tion is  fl ush edint othe manif old viath epl um bin g. In this man ne r,th e s ensor compon ent i s ca li br a ted  withou t  r e m ovin git  fro m t he  clea n en v iro nment o f the pac kag i ng.Th eabove d escription re ve als one of  t heproble m s  with th e packaging used for th e  medica l d evice . Be fore thesen sor co mpo n ent ca n be c alibr at ed, t he hy d r at ion  s olution in w hic h itis  sto red mus t be removed fromt hepackaging and  re plac e d  w ith th e  ca li b rat i o n solution. Thi s processin t ro duces seve r alun desirab le comp licat i ons. It  would th erefore b edesi r a ble  to calibr ate thesensor co m ponen t  w ithou t r emovin gitfromthe cl e anenvir onment  o f thepacka ge  and wit hout removing the hydra tion s oluti on.  The pres ent inv ention co ntri butes to a tta ini ng th iso bject ive. It  is known  top roduce th e rm opl a s ti c resin foa m i n s heetfor m  by co mpou nding such a resi n , e.g., polyet hyle n e , w ith a th er mally-decompos abl eb l owing ag en t, e.g., az odicarbo na m ide,heat-p lastif ying th e co m positi on u nde r conditi ons  n o t causi ng  d e compos itio nof the  blowi n g ag e n t and fabricatin g the r e froma  no n-cel lu lar she e t, c rosslinkin g that shee t, e.g ., b y hig h energ yelectr onir radiation, to obtain  a cr osslink ed  foa mab le she et,a n d hea ting  t hat  crosslin k e ds he et toeffe ct de co mpos ition oft he blowi nga gent an dfor m a tion o f  g a s -filled pr edo minat e l y closed c e llsi na  resu ltingfoamed  resins hee tproduct . H o w ever, itis diffic u ltto  hea t the cr os slin ke d s he et product unif ormly th roughout t o obta inu nifo r m foam in g, particula rly i na  contin u o usmanner. Mor eov er,  the  fo amin g  sheet is expanding in a ll d irect i ons  whil e the  r esin isi n he at-softe n ed condition;  in that staget hes heet  wo u ld  s ag and
 contents,_including the_exterior surfaces of the_components, are_sterilized_by exposure_to_gaseous ethylene oxide_(ETO). During the_sterilization procedure, the plumbing_is adjusted so_that_the sensor is exposed to the ambient environment, i.e., the sterilizing gas. After sterilization,_the_plumbing is_adjusted_and_the medical device is hydrated_within the package by directing_the hydration_solution from the hydration solution pouch to the_sensor_by means of_the plumbing. To allow storage of the package for_an extended period of time, a_gas-impermeable bag is_provided_to_define a chamber in_which the ambient sterile environment of_the plumbing is preserved, while the_sensor component remains immersed in the hydration_solution.
Prior to using the medical device,_the sensor component must be_calibrated. A_portion of the plumbing remote_from the sensor_component is_removed from the_packaging. A reservoir including a calibration_solution is connected_to the plumbing, and the calibration_solution_is conveyed to_the_sensor_component. As_the calibration solution_is_introduced to_the_sensor component, the hydration solution is_flushed_into the manifold via the plumbing. In_this manner, the sensor_component_is calibrated without removing_it from the clean environment_of the packaging.
The above description reveals_one of_the problems_with the packaging used for the medical device. Before the sensor_component can be calibrated, the hydration_solution in which it_is stored_must_be removed from_the_packaging and_replaced with the calibration solution. This process_introduces several_undesirable complications. It would therefore be_desirable to calibrate the_sensor_component without removing it from the_clean environment of the package and_without removing the hydration solution._The_present_invention contributes to attaining this_objective. It is known to produce_thermoplastic resin foam_in sheet form by compounding such a_resin,_e.g., polyethylene, with a thermally-decomposable blowing_agent,_e.g., azodicarbonamide, heat-plastifying the composition under_conditions_not_causing decomposition of the blowing_agent and fabricating therefrom a non-cellular_sheet, crosslinking that sheet, e.g., by high energy electron_irradiation, to obtain_a crosslinked foamable sheet, and_heating_that_crosslinked sheet to effect decomposition of the blowing agent and_formation of_gas-filled predominately closed_cells in a resulting foamed resin sheet product. However, it_is difficult to heat the crosslinked sheet_product uniformly throughout to obtain uniform foaming, particularly in a continuous_manner. Moreover, the foaming sheet is expanding in_all directions while the resin is in_heat-softened condition; in that_stage_the sheet would sag and