Ventilation design conditions associated with airborne bacteria levels within the wound area during surgical procedures: a systematic review

BackgroundWithout confirmation of the ventilation design conditions (typology and airflow rate), common practice identifying unidirectional (UDAF) systems as equivalent to ultra-clean air may be misleading, but also any claims about ineffectiveness UDAF should doubted. The aim this review was assess compare system for which (mean <10 cfu/m3) within 50 cm from wound has been reported. Six medical databases were systematically searched identify select studies reporting intraoperative airborne levels expressed cfu/m3 close site, conditions. Available data on confounding factors such number persons present in operating room, door openings, clothing material included. Predictors achieving mean bacteria identified using a penalized multivariate logistic regression model. Twelve met eligibility criteria included analysis. considered had significantly higher volume flows compared with turbulent (TV) considered. Ultra-clean environments reported all UDAF-ventilated (N = 7) rooms four 11 equipped TV. On analysis, total exchange rates (P=0.019; odds ratio (OR) 95% confidence interval (CI): 0.66–0.96) type (P=0.031; OR CI: 0.01–0.71) associated cfu/m3. High-volume complying DIN 1946-4:2008 standards rate ceiling diffuser size unconditionally achieve site. In conclusion, studied articles demonstrate that high-volume perform are superior TV reducing Without pioneering study by Sir John Charnley 1964 [[1]Charnley J. Clean-air enclosure.Br J Surg. 1964; 51: 202-205Crossref PubMed Scopus (80) Google Scholar] paved way universal use modern significant reduction surgical site infection (SSI) following hip replacement procedures UDAF-equipped traditional systems. Several years later (1969), lead same author [[2]Charnley Eftekhar N. Postoperative prosthetic arthroplasty hip-joint. With special reference bacterial content room.Br 1969; 56: 641-649Crossref (312) strong correlation between SSI sampled procedures. A similar narrative followed findings Medical Research Council (MRC) published another landmark 1983 Lidwell et al. [[3]Lidwell O.M. Lowbury E.J. Whyte W. Blowers R. Stanley S.J. Lowe D. Airborne contamination wounds joint operations: relationship sepsis rates.J Hosp Infect. 1983; 4: 111-131Abstract Full Text PDF (193) Scholar], containing during 8055 knee operations. MRC substantial benefit SSIs if concentration near did not exceed geometric 10 cfu/m3, only achieved Following these conclusions, many national today [4DINDIN 1946 Raumlufttechnik e Teil Raumlufttechnische Anlagen Gebäuden und Räumen des Gesundheitswesens Deutsches. Institut für Normung e.V, Berlin, Germany2008Google Scholar, 5Department HealthHTM 03-01:2007. Heating systems-specialised healthcare premises, part A: validation. Department Health, London2007Google 6Swedish Standard InstituteMikrobiologisk renhet i operationsrum–Förebyggande av luftburen smitta– Vägledning och grundläggande krav». SIS, Stockholm2015Google define threshold value activities, i.e. generally accepted requirement limit defining rooms. Despite growing evidence recent correlating [[7]Darouiche R.O. Green D.M. Harrington M.A. Ehni B.L. Kougias P. Bechara C.F. al.Association Microorganisms Operating Room Implant Infections: Randomized Controlled Trial.Infect Control Epidemiol. 2017; 38: 3-10Crossref (20) Scholar,[8]Stauning Bediako-Bowan A. Bjerrum S. Andersen L.P. Andreu-Sánchez Labi A.K. al.Genetic isolated samples infections at major teaching hospital Ghana.J 2020; 104: 309-320Abstract (5) systematic reviews meta-analyses registry [[9]Bischoff Kubilay N.Z. Allegranzi B. Egger M. Gastmeier Effect laminar infections: meta-analysis.Lancet Infect Dis. 17: 553-561Abstract (89) Scholar,[10]Bao Li effect used room infection: meta-analysis.Infect 2020 Dec 1; : 1-6https://doi.org/10.1017/ice.2020.1316Crossref (3) have initiated debate their (in)efficiency rates. It noted vast majority contain information conditions, or minimum defined German standard 1946-4 [[5]Department increased more than threefold: 2400 m3/h 1999 9000 2008. These values indicate factor (given velocity), new guidelines require larger 3.2 × (10.24) m2. support revisions, large-size diffusers shown reduce microbiological smaller sized [11Diab-Elschahawi Berger Blacky Kimberger O. Oguz Kuelpmann al.Impact different-sized flow versus no counts orthopedic surgery.Am Control. 2001; 39: 25-29Abstract (55) 12Wagner Schreiber K.J. Cohen Improving control.ASHRAE Journal. 2014; 8-27Google 13Benen T. Wille F. Clausdorff L. Influence different ventilations upon devices.Hyg Med. 2013; 142-146Google Scholar]. Therefore, without an time For comprehensive perspective role standards, other personnel-related influencing [[14]Jutte P.C. Traversari R.A. Walenkamp G.H. Laminar flow: better choice orthopaedic implants.Lancet 695-696Abstract (10) Scholar]). 2016 staff behaviour [[15]Birgand G. Saliou Lucet J.C. behavior infectious risk rooms: what is evidence?.Infect 2015; 36: 93-106Crossref (53) found both openings contamination. This supported observational traffic [[16]Stauning M.T. Opintan J.A. Kurtzhals J.A.L. al.Traffic microbial 2018; 99: 263-270Abstract (19) Scholar,[17]Birgand Azevedo C. Rukly Pissard-Gibollet Toupet Timsit J.F. al.Motion-capture movements openings: Impact surrogates surgery.Infect 2019; 40: 566-573Crossref (6) Another affects body exhaust suits helmet [[18]Young S.W. Zhu Shirley O.C. Wu Q. Spangehl M.J. Do 'surgical systems' 'body suits' affect deep arthroplasty? review.J Arthroplasty. 2016; 31: 225-233Abstract (31) However, absolute comparison measured critical zone cannot performed careful consideration sampling devices [[19]Romano Gustén Joppolo C.M. Ljungqvist Reinmüller Some aspects efficiency impaction samplers.Particuology. 20: 110-113Crossref (7) we decided characteristics zone, including available activity level, surgery, material, suits/exhaust gowns. After finalizing selection, aimed relative contribution (i.e. flow) study, according Preferred Reporting Items Systematic Reviews Meta-analyses (PRISMA) [[20]Liberati Altman D.G. Tetzlaff Mulrow Gøtzche Ioannidis J.P.A. al.The PRISMA statement evaluate health care interventions: explanation elaboration.BMJ. 2009; 339: b2700Crossref (8803) original articles: Medline, EMBASE, Ovid, Web Science, Cochrane, WHO regional databases. list search terms, “operating rooms”, “airborne contamination”, “bacterial load”, used, Subject Headings (MeSH). limited English-language articles. last conducted 24th July 2020. Two independent reviewers screened titles abstracts retrieved references potentially relevant studies. full text eligible obtained then reviewed two authors working independently each other. first screening inclusion developed addressed environment, excluding clinical wards clinics. Second, selected report outcome system. third set screen texts detail. information: (1) count (?50 wound) either Sartorius MD-8 Air Scanner Klotz FH series sampler; (2) parameters, least exchanges per hour (ACH) supply volumetric (m3/h L/s). one those method. We, therefore, include filter sampler (Sartorius Scanner) slit-to agar (Klotz series), specific types samplers statistical difference (P<0.05) (cfu/m3) ongoing surgery [[21]Ljungqvist Tammelin Comparison measuring methods active viable particles.European Journal Parenteral Sciences. 2012; 56-59Google Also, recommended Swedish Institute cleanliness [[6]Swedish Publications describing research (conference proceedings, reviews, letters, commentaries) excluded duplicate publications removed. written English language, 1990 30th April All our cross-sectional Unlike interventions assigned patients, exposure target culture media. Because patients involved outcome, most quality assessment tools [[22]Ma L.L. Wang Y.Y. Yang Z.H. Huang Weng H. Zeng X.T. Methodological (risk bias) primary secondary studies: they better?.Mil Med Res. 29 (1): 7Google could applied, limiting usefulness. chose illustrate individual key elements methodology eleven Quality Assessment Tool Quantitative Studies (ICROMS) [[23]Zingg Castro-Sanchez E. Secci F.V. Edwards Drumright L.N. Sevdalis al.Innovative assessment: integrated multiple designs (ICROMS).Public Health. 133: 19-37Crossref (45) awarded 2 points criterion met, 0 1 point it unclear. Based recommendations ICROMS, scores <60% maximum attainable score labelled high bias, 60–80% medium reliability >80% reliability. Given objectives capture literature, exclude based provided. co-authors assessed against criteria, discrepancies resolved seeking further opinions consensus authors. Four (B.L., B.R., R.T.); none papers. Data extracted researcher checked second predesigned spreadsheet. From extracted: source details, authors, year publication, type, procedure, procedures, sampler, position wound, personnel inside helmets suits, system, When group, determined whether reports population frame collection sources, removed duplicates. We dichotomized dependent variable <5 max <30 variables treated continuous (number exchanges, procedures) categorical (whether helmets/body exhausts used; woven vs non-woven clothing: cotton while contained cotton. reported, assumed made conventional material). Each potential separately predefined levels. Fischer's exact test groups binary comparing variables. If P-value less 0.2, retained analysis Due sample size, option. Instead, Firth procedure sparse rare [[24]Devika Jeyaseelan Sebastian Analysis research: newer approach.J Postgrad 62: 26-31Crossref (23) significance P<0.05 (two-tailed). analyses Stata version 16 (StataCorp, College Station, TX USA). Our initial yielded 2,823 removing duplicates, 1767 unique papers remained, 1267 after abstract review. remaining 91 underwent full-text criteria. Of those, 76 because leaving 12 final chart (Figure 1). marked heterogeneity prevented meta-analysis. field real-time studies, eight infection-control journals, three pharmacy journal. dates ranged 2019, (8/12) past decade (2010–2019). countries: Sweden 10), Finland 1) Netherlands varied seven 250 study. location 0.2 m 0.5 m. Seven nine surgeries, openings. mentioned, non-existent calculated size. case missing contacted through room. explicitly, single measurement results. outlined Supplementary Data. An overview can Table I.Table IDescriptive summary characteristics, proceduresRef.Type procedureType systemTotal (ACH); (m3/h); inlet (m2)No. proceduresType samplerSampling zoneNumber roomTraffic openings)Use suitsClothing materialAir (cfu/m3)Andersson (2014) [[25]Erichsen Andersson Petzold Bergh I. Karlsson Eriksson B.I. Nilsson K. mixed influence human factors: experiences center.Am 42: 665-669Abstract (51) Scholar]Orthopaedic implant proceduresVertical UDAF67 ACH;9160 m3/h;3.6 x 3.6 m2N 33Sartorius Scanner?30 wound5 ± 1.1 SD;2–9 (range)11.4 8.9 SD);2–31 (range)No50% cotton, 50% polyester1.00 2.10(mean SD);0–18 (range)Alsved (2018) [[26]Alsved Civilis Ekolind A.E. Jakobsson al.Temperature-controlled airflow.J 98: 181-190Abstract (38) surgeriesVertical UDAF100 ACH;12 000 m3/h;2.75 2.75 15Sartorius & FH5?40 wound7 (median);5–9 (range)3.8/h (median);1.4/h–11/h (range)No69% 30% polyester, 1% carbon fibre0.00 (median);0–16 (range)Temperature-controlled airflow47 ACH;5600 m3/h;N 157 (median);6–9 (range)2.1/h (median);0–10/h (range)1.00 (median);0–29 (range)Turbulent ventilation27 ACH;3200 m3/hN (median);6–8 (range)5.6/h (median);0–11/h (range)10.00 (median);0–162 (range)Friberg (2003) [[27]Friberg Ardnor Lundholm Friberg addition mobile exponential reduces box levels.J 2003; 55: 92-97Abstract (43) Scholar]Groin hernia surgeryTurbulent ventilation16 ACHN 10Sartorius Scanner20 above patient's chest6.3 0.7 SD1.4 ±1.4 SD)Yes70 % 30 nylon27.40 9.90 SD)Mobile UDAF+Turbulent ventilation400 m3/h;0.55 0.4 m2+16 505.7 0.8 SD)1.9 1.5 SD)8.90 4.80 SD)Kasina (2016) [[28]Kasina Blomfeldt A.M. Ottosson distinct clean decrease load room: study.Patient Saf 7: 1Crossref Scholar]Total replacementMobile ventilation220 L/min+17 ACH; 620 L/sN 13Sartorius Scanner?35–50 field6 (mean);6 (max)1No69% fibre27.90 (mean);20.0 (median);1–148(range)Turbulent ventilation17 136.84 (mean);9 (max)Polypropylene/polyethene material38.90 (mean);22.5 (median)0–228 (range)N 118 (max)Polypropylene22.8* (mean);12.0 (median);0–280 (range)Ljungqvist (2012) surgeriesTurbulent ventilation22 ACH;2736 2Sartorius Scanner?30–50 field7.5 (mean);7–8 (range)Not reportedNo69% fibre47.75 *(mean);27-88 37.5 (range)99% fibre,120 g/m25.5 (mean);1–13 (range)Vertical UDAF104 ACH2736 (range)69% fibre1.6 (mean);1–4 (range)Sanzen (1990) [[29]Sanzen Carlsson A.S. Walder ultraclean enclosure clothing.J Arthoplasty. 1990; 5: 127-130Abstract (30) arthroplastyVertical UDAF590 Scanner?20 woundNot reportedNot reportedNoDouble layer (cotton scrubs under gown)1.4 (mean);1.4 (median);0.3–2.9 10YesDouble gown)0.4 (mean);0.3 (median);0.2–0.6 10NoDouble (polytetrafluoroethylene (mean);0.4 (median);0.4–0.8 gown)0.9 (mean);0.8 (median);0.5–1.8 (polyester (median);0.3–0.7 (range)Tammelin [[30]Tammelin Reinmuller protection air-borne bacteria: prospective Saf. 6: 23Crossref (25) ventilation29 ACH*;996 4Sartorius Scanner?20–50 wound7.2 fibre26.75 (mean);9–55 ventilation28 ACH*;965 36.3 (mean);5–7 (range)32.1 (mean);9–65 ventilation31 ACH*;1050 37 (mean);7–7 fibre12.1 (mean);1-40 27 (mean);6–8 fibre,100 g/m219.95 (mean);7–40 g/m24.25 (mean);1–12 ACH*;755 (mean)6–8 (range);69% fibre41.33 (mean);12–88 1Not reported99% g/m27.0 27.3 g/m24.75 (mean);2–9 (range);Tammelin (2013) [[31]Tammelin Single-use room.J 84: 245-247Abstract Scholar]Hip arthroplastyTurbulent ventilation24 ACH;845 L/sN=5Sartorius wound5.8 (range)2.2 (mean);1–3 fibre11.00 (mean);1–36 (