70 Porcent Alcohol Disinfection of Transducer Heads - Experimental Trials

8/13/2019 70 Porcent Alcohol Disinfection of Transducer Heads - Experimental Trials

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70% Alcohol Disinfection of Transducer Heads: Experimental TrialsAuthor(s): George H. Talbot, Maureen Skros, Mary Provencher

Reviewed work(s):Source: Infection Control, Vol. 6, No. 6 (Jun., 1985), pp. 237-239Published by: The University of Chicago Presson behalf of The Society for Healthcare Epidemiology ofAmericaStable URL: http://www.jstor.org/stable/30145027.

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7 0 Alcohol isinfection oTransducerHead s Experimentalr i a l sGeorgeH.Talbot,MD;MaureenSkros,RN,BSN;MaryProvencher,MT ASCP)

ABSTRACTWe investigated the feasibility of transducer headdisinfection with 70% alcohol wipes. In the initial trial,nine gas-sterilized transducers were inoculated with anestimated 5 x 106organisms of a clinical isolate of Enter-obactercloacae, mimicking a contaminated fluid couple.A sterile disposable transducer dome was attached toeach transducer. The units were allowed to sit for 24hours at room temperature; the domes were thenremoved. Three transducer heads were cultured priorto disinfection to ensure that viable organismsremained. Each transducer head was wiped clean with asingle alcohol wipe, allowed to dry, and then cultured.All nine cultures showed growth of E. cloacae. A secondseries of trials with 54 transducers employed an identi-cal protocol, except that each transducer head receivednot one, but two, applications of alcohol. In addition toE. cloacae (26 runs), Staphylococcus aureus, Pseudomonasaeruginosa and Candida albicans were employed in nine,nine and ten runs, respectively. Cultures of 53 of 54transducer heads showed no growth; the single positiveculture was attributed to an error in technique. Thesepreliminary results suggest that the double-alcohol-wipe technique may be an easy, cost-effective, alter-native or supplemental method of transducer head dis-infection. However, we do not advocate routine imple-mentation of this technique in patient care settings untilclinical trials confirm its safety and efficacy. [InfectControl 1985; 6(6):237-239.]

From theInfectiousDiseasesSection,DepartmentofMedicine,UniversityofPennsylvaniaSchoolofMedicine,and theInfectionControlSection,Hospitalofthe Universityof Pennsylvania,Philadelphia,Pennsylvania.Presented n abstractorm at the Eleventh Annual Meeting of theAssociationfor Practitioners n InfectionControl,Washington,D.C., May 1984.The authorsacknowledgehe assistanceofDr. MichaelSimson,DianeAdler,Hazel Price, Dr. Daniel Kacian, Dr. Elaine Larson,Dr. Rob RoyMacGregor,;Dr. Irving Nachamkinand the Divisions of Critical Care Nursing, CentralServices,and ClinicalEngineering.Address eprintrequests o GeorgeH. Talbot,MD, InfectionControlSection,Hospital of the Universityof Pennsylvania,3400 SpruceStreet,Philadelphia,PA 19104.

INTRODUCTIONIntravascular pressure monitoring has assumed

increased importance in the management of critically illpatients. However, the potential benefits of such pro-cedures may be offset by associated risks, including infec-tion due to the catheter or to contaminated infusate.'-7Even the transducer head may serve as a reservoir formicroorganisms, with transmission to the patient occur-ring by direct passage of organism through microscopiccracks in the dome diaphragm or on hands of personnelduring manipulation of line connections, sampling portsand stopcocks.4 Use of a disposable dome does not obvi-ate the need for disinfection or sterilization of the trans-ducer. Several studies document the failure of disposabledomes to prevent septicemia from contaminated trans-ducer heads.2'4'6Accordingly, the Centers for Disease Control recom-mend high-level disinfection or sterilization of trans-ducers between patient use.8 One potential obstacle toimplementation of this approach is the cost of centrallylocated disinfection or sterilization, including the expenseof processing itself, plus that of any additional trans-ducers needed to allow continued patient monitoringwhile processing is performed. We therefore investigatedthe feasibility of a disinfection procedure that could beperformed at the bedside. The method of disinfectionchosen for study in these trials was direct application of70% isopropyl alcohol to the transducer head.

METHODSA series of experiments was performed to evaluate theefficacy of disinfection of transducer heads with pre-packaged 70% isopropyl alcohol wipes (Webcor AlcoholPreps, The Kendall Company). In the first experiment,nine transducers were gas-sterilized in appropriate pack-aging. At the time of the experiment, each transducer wasplaced in a transducer holder. Handwashing was per-formed prior to all manipulations, and care was taken toavoid contact with the transducer head. A suspension of aclinical isolate of Enterobacter loacaewas prepared in tryp-ticase soy broth and adjusted to a McFarland 0.5 turbidityINFECTION CONTROL1985/Vol. 6, No. 6 237


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TABLEEFFICACYOF DISINFECTIONOFTRANSDUCER HEADS WITH70% ALCOHOL WIPESSample PostOrganism Size* Controlst Alcohol

Single WipetEnterobactercloacae 9 3/3** 6/6 **DoubleWipetEnterobactercloacae 35 9/9 1/26Staphylococcusaureus 12 3/3 0/9Pseudomonas

aeruginosa 12 3/3 0/9Candidaalbicans 10 2/2 0/10*Number f transducerheads inoculatedwithtest organism.tResults prior o application f 70% alcohol.*Applicationsf 70%alcohol, as described n text.S*Transducereads showing growthof the test organism/trans-ducer heads sampled.

standard (108 organisms/ml) in non-bacteriostatic saline.One drop (approximately 50 p1of this solution con-taining an estimated 5 x 106organisms wasplaced on eachtransducer head. A sterile disposable transducer domewas attached to each transducer head. The transducer-dome units were allowed to sit undisturbed at room tem-perature for 24 hours. The domes were removed andthree transducer heads immediately were swab culturedto ensure that viable organisms remained ( controls ).The remaining transducers were then wiped clean with asingle alcohol wipe, allowed to dry, and cultured, asdescribed below. The 24-hour delay between inoculationand disinfection was intended to mimic a clinical scenarioin which attempted decontamination was performed aday or more after inadvertent use of contaminated fluid asthe couple between transducer head and transducerdome. Previous clinical studies have shown that organismscan easily be recovered from contaminated fluid couplesin in-use pressure-monitoring systems.2,4 Furthermore,contaminating organisms readily survive in such fluidcouples under experimental conditions.9 We anticipatedthat use of trypticase soy broth, a microbiologic mediumwhich facilitates bacterial growth, would produce an evengreater challenge to the disinfection procedures chosenfor study.In a second series of trials, 54 transducer heads weredisinfected using a double-alcohol-wipe technique. Thesame protocol as the single-wipe method was utilized withthe following exception: transducer heads were wipedwith alcohol, allowed to dry, and then wiped again. Afresh wipe was used for the second alcohol application.Cultures were obtained after the second application ofalcohol had dried. Clinical isolates of E. cloacae,Staphy-lococcus aureus, Pseudomonas aeruginosa and Candida

albicans were applied to the transducer heads in fourorganism-specific trials in this series. The bacterial iso-lates were prepared as described above for E. cloacae. C.albicans inocula were prepared from a 48-hour culturegrown on Sabouraud's agar. A suspension wasprepared insterile saline and adjusted to a transmission of 95% asmeasured at a wavelength of 530 nm. This preparationyields a final concentration of approximately 106 cells perml.For isolation of E. cloacaeand P. aeruginosa,swabs wereinoculated onto MacConkey agar and thioglycolate broth,then incubated at 300 to 37oC for 48 hours. Plates wereread at 24 and 48 hours; broths were stained at 24 hoursand subcultured to MacConkey agar. E. cloacaewasidenti-fied by colony morphology, lactose fermentation charac-teristics, and indole negativity. P. aeruginosawas identifiedby the API system. Swabs from the S. aureus trials wereinoculated onto blood agar and thioglycolate broth. Theorganisms were identified by colony morphology, betahemolysis, and coagulase positivity. Isolation of C. albicanswas performed on blood agar plates and Sabouraud'sglucose broth. Organisms were identified by colony mor-

phology and germ tube production.'0RESULTSResults of these disinfection trials are shown in theTable. Use of the single-wipe technique did not eradicatethe test organisms from the transducer heads in anyinstance. In contrast, use of the double-wipe methodproved efficacious in 53 or 54 runs, using four test organ-isms. The single positive result was attributed, in retro-spect, to inadvertent omission of the second alcoholapplication, but this could not be proven. The differencein efficacy between the single-wipe and double-wipe tech-niques was significant (p


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several hundreds of dollars each. At our hospital, thisfigure is $450.00 for the Gould Statham P23.r In aninstitution with a high turnover of patients requiringintravascular pressure monitoring, additional trans-ducers may be needed if centralized disinfection or ster-ilization takes more than a few hours. Added to this arethe expenses of processing itself, plus the cost of replace-ments for transducers damaged or lost in transit. A lessexpensive but equally efficacious method of transducercare might be desirable for some patient care facilities,pending introduction of inexpensive, disposable trans-ducers.

Seventy percent isopropyl alcohol has been demon-strated to be bactericidal against the vegetative form ofgram-positive and gram-negative bacteria.2 It is not sur-prising, therefore, that under the experimental condi-tions described, the double-alcohol-wipe technique waseffective in removing each of four common nosocomialpathogens from transducer heads. The techniqueappeared efficacious for our clinical isolates of E. cloacae,P. aeruginosa,S. aureus, and C. albicans.Double-alcohol wiping might represent an alternate orsupplemental method for care of in-use transducers,especially since it is easy to perform and therefore suitablefor routine use at the bedside. Clinical situations appro-priate for use of this technique might include routinedisinfection of transducers during prolonged monitoringof a single patient or disinfection between patients notknown to be infected with bloodborne pathogens. Elim-ination of the fluid couple may further reduce the risk ofsepticemia. Thorough cleaning and gas or chemical ster-ilization of any transducer contaminated by blood or byother potentially infectious body fluids would be prudent,and of course, adherence to other accepted measures forprevention of intrasvascular pressure monitoring device-associated infections8 would be mandatory. Careful hand-washing prior to any manipulation of such systems seemsessential. Further work is necessary to determine optimal

methods of, and conditions for, implementation of thisprocedure. Specifically, we do not advocate routine imple-mentation of this technique in patient care settings untilclinical trials confirm its safety and efficacy, as well as itspossible effect on transducer integrity.6One major advantage of this technique is its low costApproximately 2 to 3 minutes of nursing time would berequired, plus two alcohol wipes ($.01 each). Given thevirtual certainty of increased financial pressure on healthcare providers, further consideration of the possible mer-its of the double-alcohol-wipe technique seems war-ranted.REFERENCES1. Maki D: Nosocomial bacteremia. An epidemiologic overview. Am] Med 1981;70:719-732.

2. MlakiD, Hassemer C: Endemic rate of fluid contamination and related sep-ticemia in arterial pressure monitoring. Am] Med 1981; 70:733-738.3. Cortez L, Hadlev K, Schluter I: Transducer-associated nosocomial primarlybacteremia: Identification and control. Proceedings of the 19th InterscienceConference on Antimicrobial Agents and Chemotherapy. Abstract 209,October 1-5, 1979.4. Donowitz LG, Marsik FJ, Hoyt JW, et al: Serratiamarcescens acteremia firomcontaminated pressure transducers. ]AMA 1979; 242:1749-1751.5. Aduan A, lannini P, Salaki J: Nosocomial bacteremia associated with con-taminated blood pressure transducers. Report of an outbreak and a review ofthe literature. Amj Infect Control 1980; 8:33-40.6. Buxton A, Anderson R, Klimek J, t al: Failure of disposable dome to preventsepticemia acquired from contaminated pressure transducers. Chest 1978;74:508-513.7. Solomon SL, Goodpasture HW, Alexander H, et al: Nosocomial Candida

parapilosiosisnfections in a neonatal intensive care unit. Proceedings of the 23rdInterscience Conference on Antimicrobial Agents and Chemotherapy.Abstract 815, October 24-26, 1983.8. Simmons B: Centers for Disease Control: Guideline for prevention of intra-vascular infections. AmJ Infect Control1983; 11:183-193.9. Gordon AS, Mowrav S, ColeJ: Microbiological isolation and pressure accuracywith disposable diaphragm domes for pressure monitoring. Proceetlings ofthe Association for the Advancement of Medical Instrumentation, 16thAnnual Meeting, 1981.10. Lennette EH, Balows A. Hausler WJ, Truant JP (eds): Manual of ClinicalMicrobiology, d 3. Washington, D.C., American Society for Microbiology.11. Rose R, Hunting K, Townsend T, et al: Morbidityand mortalityand economicsof hospital-acquired blood stream infections: A controlled study SouthMed]1977; 70:1267-1269.12. Morton HE: Alcohols, in Block SS (ed): Disitnfection, terilization, lndPreserva-tion, ed 3. Philadelphia, Lea and Febiger, 1983, pp 225-239.

INFECTION CONTROL 1985/Vol. 6, No. 6 239

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70 Porcent Alcohol Disinfection of Transducer Heads - Experimental Trials