Evidence suggesting that microbial aerosols can be responsible for - - PDF document

6/16/2018 1 Charles E. Edmiston Jr., PhD., CIC, FIDSA, FSHEA, FAPIC

Emeritus Professor of Surgery

• Department of Surgery

Medical College of Wisconsin, Milwaukee, Wisconsin USA edmiston@mcw.edu

Air Contamination and SSI Risk: Do We Need a New Standard in an Era of Device - Related Procedures?

No Conflict of Interest to Report

6/16/2018 2

Discussion Points

• The historic role of the operating room (environment of care)

as a risk factor for infection

• Evidence suggesting that microbial aerosols can be

responsible for surgical site infections

• Modern air-handling strategies for the operating room

environment

• Innovative strategies to reduce a proposed risk
• Is it time to proposed a standard for microbial airborne burden

in the operating room environment

• What is the economic consequences in an era of fiscal

liability?

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“It’s all about the surgical wound”

“….all surgical wounds are contaminated to some degree at closure – the primary determinant of whether the contamination is established as a clinical infection is host (wound) defense” Belda et al., JAMA 2005;294:2035

• 2042

Quantitative Risk of Infection

Microbial Burden In the Wound (~10

5

) x Microbial Virulence Host resistance (wound defense) Overall risk of SSI

=

A Foreign Body Trumps This Equation

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Extrinsic Risk Factor: Bacterial Colonization

• f Implantable Devices
• Implantable Device

– Pathogenesis of Infection

• Implants provide

nidus for bacterial adherence

• Bacterial colonization can lead to

biofilm formation

• Biofilm formation enhances antimicrobial recalcitrance

As little as 100 staphylococci can initiate a device

• related

infection

Ward KH et al. J Med Microbiol. 1992;36: 406

• 413.

Mangram AJ et al. Infect Control Hosp Epidemiol.1999;27:97

• 134

Edmiston CE, Problems in General Surgery 1993;10: 444 Edmiston CE, J Clinical Microbiology 2013;51:417

The historic role of the operating room ( environment of care) as a risk factor for infection

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The “Good Old Days” in the Operating Room

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Evidence suggesting that microbial aerosols can be responsible for surgical site infections

«

The airborne component of postoperative wound infection is not a fixed rate but rather varies from hospital to hospital, from OR to OR, and from surgical team to surgical team. The rate is proportional to the number of disseminating carriers in the room

• aerosol contamination

accounts for 20

• 24

% of postoperative infections”

"You are villains in a plot against your patients. Because of your negligence, 90 percent of the nation's hospitals are a menace to health." Carl W. Walters, MD

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Epidemiology of Total Joint Infections

“ The personnel who enter the OR carry the bacteria”

• Presence of OR personnel
• increases shedding by a factor
• f 40X
• % to 30% of all OR personnel

20 – Staphylococcus aureus carriers

• “High shedders” (>10,000 bacteria/min):

13 % males 5 % postmenopausal females 1 % premenopausal females

Ritter MS., Clin Orthop Relat Res. 1999;369:103

• 109.

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Edmiston et al, AORNJ 1999;69:1169

Seabrook GR, et al. J Vasc Surg. 1990;11:629

• 634

6/16/2018 10 0.45 m m Filter Culture Media

Incubate 48 hours 35

• C (30
• C)

Microbial Recovery IDENTIFICATION Cascade Impactor

Intraoperative Measurement of Microbial Populations Within the Operating Room

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Vascular Operating Room

• Cascade Impactor

Table

• Personnel

Intake vent Intake vent

• Colored dots

– unique staphylococcal strains recovery from anterior nares

3 a 3b 4a 5a 9a 11a MSM 7a 7b 1a 1b 1c 1d

Edmiston et al, Surgery 2005; 138; 573

• 582

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Does operating room traffic influence particulate (viable/nonviable) dispersion?

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Infect Control Hosp Epidemiol 2018;1 – 7

Rezapoor et al, J Arthroplasty 2018;33:851

• 855

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Teter J, et al. Am J Infect Control. 2017;45:477

• 482

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Modern air - handling strategies for the

• perating room environment

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Typical “Laminar

• Flow” Design Used in Most

Hospital Operating Rooms

Air Curtain Multi

• Diffuser Array

Single

• Large Diffuser

Modified from: Dr. Jenifer Wagner, Air Media Magazine, Summer 2014

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Goddard, K.R. Factors involved in providing cleaner environment in surgery. Air Engineering, July 1965

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• Airflow velocity and microbial load between the back table and

sterile field was highly variable among the operating rooms tested.

• To date there is no scientific evidence to support that increasing the

ventilation rate to a higher levels actually reduces SSIs.

• Use of environmental quality indicators (EQI) such as level of

microbial contamination, number of particles (non

• viable/viable)

and air velocity at key point in the operating room may provide a more accurate assessment of risk.

Current HVAC systems, including laminar flow and positive pressure systems, do not deactivate microbial aerosols, but displace the microorganisms. Which are continuously being shed within the OR setting, contributing to the airborne (and surface) microbial burden. TURBULENT ZONES KEEP MICROBIAL PARTICLES IN SUSPENSION

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Innovative strategies to reduce a proposed risk

Marginalizing Air Currents in the Operating Room Environment

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Nakajima et al. Eur J Orthop Surg Traumatol 2017;27:1139

• 1143

Oct

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Nakajima et al. Eur J Orthop Surg Traumatol 2017;27:1139

• 1143

Young et al. J Arthroplasty 2016;31:225

• 233

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Young et al. J Arthroplasty 2016;31:225

• 233

Novel HEPA Filtered Air Delivered to the Surgery Site (Active)

“ Airborne CFUs (viable) ……are a likely source of contamination leading to device

• related infections.”

Darouiche et al. ICHE 2016;1

• 8.

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Ultraviolet ( UV

• C)/Visible Germicidal Irradiation

Novel UV Air Disinfection System (Passive/Active Technology)

Maury Regional Hospital Columbia, TN

56 % Reduction 88 % Reduction

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Is it time to proposed a standard for microbial airborne burden in the operating room environment?

• Documented to reduce airborne bacteria levels

in operating rooms by 50

• 60

%.

• Peer
• review: Crystalline UVC was highly effective

at significantly ( p<0.05 ) reducing total and viable particle counts related to routine activity within a controlled operating room environment.

• Further studies are warranted to assess the risk

reduction benefit in TKA and THA orthopedic cases.

J Arthroplasty. 2017 Dec 5. pii : S 0883

• 5403(17)31057
• 4

. doi : 10.1016/j.arth.2017.11.052. [ Epub ahead of print

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Air Quality in the OR

• The standard (ISO) for airborne contaminants in the “clean room”
• f a typical semiconductor manufacturer is well defined (ISO Class

1 to Class 4)

• These stringent requirements minimize the fiscal loss that is

associated with product failure in a highly sensitive manufacturing environment.

• The difference in the design of HVAC systems in hospital ORs and

facilities designed to meet ISO requirements can be radical.

• In the typical OR the arrangement of airflow diffusers over the
• perating table would not be acceptable to ISO Class 1 to 4.
• ASHRAE Standard 170 and AIA guidelines do not represent an

evidence-based aerobiological risk-adjusted standard.

Number of Airborne Particulates per ISO class

Compounding pharmacies must comply with International Standards Organization (ISO) class 5 standards for air quality

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Air Quality in the OR

• Current guidelines do not address specific criteria for the quantitative

reduction of viable microbial aerosols in the OR environment.

• The EU has proposed the development of new air quality standards for

the hospital environment based on patient risk.

1

• 3
• “There is a direct link between the number of particles in the OR and

the number of personnel present in the case.”

4

• 1. Charkowska A. J

Occup Safety Ergon 2008;14:447

• 453

. 3. Lidwell OM, et al. BMJ 1982;285:10

• 14.
• 2. Andersson AE, et al. AJIC 2012;40:750
• 755

. 4 . Parvizi et al. AJIC 2017;45:1267

• 1272.

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What is the economic consequences in an era of fiscal liability?

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Periprosthetic Joint Infections

• 2.18% of hip and knee

implants become infected

• Overall lifetime cost for

a single case of a septic THA (age 65) using a

• neway sensitivity

analysis of $390,806 per patient.

• PJI is associated with a

mortality rate of between 2 – 7%

• Experts report that the five-year

survival rate of patients with PJI is worse than with most cancers.

Historical and projected number of infected THA, TKA, and total (THA + TKA) procedures in the United States.

Parisi TJ, et al. Clin Orthop Relat Res. 2017;475:1891-1900 Kurtz et al. J Arthroplasty 2012;27:61-64

Projected Trends and it is not Pretty

$3

• 5

Billion* $1.6 Billion*

*Projected Cost of PJI

4 Million TJRs by 2030

Tisosky et al. J Am Acad Orthop Surgeons 2017;1:e34

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“It is not the air, it is something in the air”

Lister 1861