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IntroductionThe AnaConDa® (Sedana Medical, Uppsala, Sweden) is a reflectionfilter that can be used to administer volatile anesthetics to intubatedpatients on a conventional ventilator outside the OR. We have recentlyimplemented sevoflurane as a sedative in our ICU and found that littledata are available on staff exposure and ambient pollution when usingthe AnaConDa® (Fig. 1). A risk analyses was performed, as requestedby our occupational health service. We have measured ambientpollution, staff exposure and peak values of sevoflurane on allconnection points of the AnaConDa® system and FlurAbsorb scavengerin a Critical Care setting (Fig. 2) . Aim of this study was to quantifyambient pollution and staff exposure to sevoflurane while using theAnaConDa® and relate it to current safety standards.
An air sampling kit was worn by a nurse tomeasure direct exposure during an 8-hourshift. This was repeated by a second nurse ona consecutive 8-hour shift with a newsampling tube. In this way, a total of fourstationary, two personal and eight real timemeasurements were performed.Analyzers were calibrated before and aftersampling. Laboratory analyses wereaccording to ISO/NEN standards. TheSwedish occupational exposure guidelineswere used as a reference, since no nationalguidelines are available. The exposure limit is5ppm (time weighted average (TWA)42mg/m3 over an 8-hour period). NorthAmerican guidelines are more strict, with amaximum of 2ppm, while in the UnitedKingdom it is more liberal, allowing exposurelimits of up to 50ppm.
ResultsOur results are summarized in table 1. Timeweighted measurements are expressed as apercentage of exposure limits (NEN 689model). An exceeding can be ruled out ifconcentrations are <10% of exposure limits.We clearly show that peak concentrations andTWA are far below the allowed occupationalexposure limits.
DiscussionThe exposure to volatile anesthetics shouldbe reduced to ‘a level as low as reasonablyachievable’ (ALARA). Local differences inICU’s necessitate quantification of exposureprior to routine use, in order to guarantee asafe work environment. Furthermore,protocols should be used to ensure astandard way of care when using volatileanesthetics.
ConclusionWe concluded that sedation with sevofluraneand the AnaConDa® system with theFlurAbsorb scavenger is safe in an ICUsetting. Occupational exposure is negligibleand meets international standards. Thesedata highly contributed to staff safetyperception and awareness. Our data may behelpful to those who want to implementvolatile anesthetics in their ICU.
The AnaConDa® and Sevoflurane in the ICU: data on ambient pollution and staff exposure
A.T. Bos MD, Anesthesiologist-IntensivistDept. of Intensive Care, VieCuri Medical Center Venlo, the Netherlands [email protected]
Fig. 2 Clinical setting
Table 1. Sample data
Fig. 1 Reflection filter and syringe
Contact: [email protected] / +31-77 320 5259
MethodsSince pollution data are patient independent and relate to the integrityof the breathing circuit, only one intubated subject was used toperform sampling. Air sampling was performed by an independentinstitute (RPS). A Miran SapphIRe portal ambient analyzer was usedfor realtime measurements on eight different connecting points of thebreathing circuit and AnaConDaÒ system, including the FlurAbsorbscavenger. Charcoal sorbent tubes (SKC226-01) were used forstationary and personal measurements and were analyzed in alaboratory (OSHA 103 method). Stationary 8 hour measurements wereperformed on two different locations in an ICU room (fig 2). Thesemeasurements were repeated with new sampling tubes.
