Re: Interpretation of the NHSN surgical site infection definition for sternotomy infections

25/09/2013 at 6:08 pm #70507 Quote

Glenys Harrington

Participant

Author:
Glenys Harrington

Email:
infexion@ozemail.com.au

Organisation:
Infection Control Consultancy (ICC)

State:

Hi Irene,

How complex an individual finds the NHSN definitions depends on; a) how
often they are using them, b) how well they have been trained (including
competency assessment) in the standardised application of the definitions
and c) quality checks that need to be in place before reporting an
infection.

The aim of surveillance for surveillance purposes (i.e. not clinical
management) is to standardise the application of the surveillance methods
and definitions so we are comparing apples with apples either over time
internally or externally

(understanding the limitations of inter-hospital comparisons and
benchmarking).

In NHSN surveillance specific sites are assigned to organ space to further
identify the location of the infection. This may not be of particular
relevance to micro, ID, IC however, it will be of interest to
surgeons/surgical registrars who for the purpose of internal audits/death
audits, registries etc may classify infections to an anatomical location in
addition to other criteria.

Given the extensive use of the NHSN definitions worldwide we should leave
any modifications/changes to CDC (who have the funds) and where we have
concerns focus on training or retraining those collecting the surveillance
data in the standardised application of the surveillance methods and
definitions.

This approach has worked well for infection control teams/infectious
diseases staff who I have trained in NHSN surveillance methods/application
of the definitions and was in a setting where the surveillance data was
utilised for research studies.

No surveillance method definitions will identify 100% of infections – the
definitions will miss some infections and on occasions will over call some
infections. As long as we are all doing the same thing (strict application
of each definition) this should not be an issue in terms of why we are
collecting the data timely feedback to relevant clinical and executive
management staff and measuring and monitoring the impact of evidence based
interventions that are implemented to improve patients outcomes.

Regards

Glenys

Glenys Harrington

Consultant

Infection Control Consultancy (ICC)

PO Box 5202

Middle Park

Victoria, 3206

Australia

H: +61 3 96902216

M: +61 404 816 434

infexion@ozemail.com.au

ABN 47533508426

Of Wilkinson, Irene (Health)
site infection definition for sternotomy infections

Hi Glenys,

Personally I believe the NHSN definitions are overly complex. I can
understand the reason for distinguishing superficial infections from
deep/organ space, but really what is the purpose of distinguishing deep from
organ space? The likely causes/sources of infection and hence preventive
measures would be similar.

Regards,

Irene

Irene Wilkinson

Manager, Infection Control Service

SA Health

Irene.wilkinson@health.sa.gov.au

Of Glenys Harrington
for sternotomy infections

Hi John,

While there is no muscle there is fascia and if involved you would proceed
with using the deep definition to see if you meet the other criteria. From
your description it seems in your cases you would meet b plus 1 signs of
infection confirming it was a deep infection.

The definition seems fairly straight forward to me and I have found it very
easy to use over the years. It is a definition for surveillance purposes
not clinical management.

By definition an organ space infection does not include the wound, hence
infection deep to the deep fascia a deep (or organ space infection) is
not the correct application of the organ space definition.

Vac dressings can be used on lots of wounds including superficial sternal
wounds (see below). The foam is cut and contoured to fit the size of the
tissue defect, and covered with an adhesive drape and connected through the
evacuation tube to the vacuum pump. There is no exposure of the wound
bed/surface using these devices.

From memory there is usually an percutaneous suture in closure of a sternal
wound.

Bapat V et al. Experience with Vacuum-assisted closure
of sternal wound infections following cardiac surgery and evaluation of
chronic complications associated with its use.
J Card Surg. 2008
May-Jun;23(3):227-33Department of Cardiothoracic Surgery, St Thomas’
Hospital, London, UK. vnbapat@yahoo.com

Dezfuli B et al, Treatment of Sternal Wound Infection With Vacuum-assisted
Closure. Wounds. 2013;25(2)

Regards

Glenys

Glenys Harrington

Consultant

Infection Control Consultancy (ICC)

PO Box 5202

Middle Park

Victoria, 3206

Australia

H: +61 3 96902216

M: +61 404 816 434

infexion@ozemail.com.au

ABN 47533508426

Of John Ferguson
site infection definition for sternotomy infections

Thanks Glenys

However, there is no muscle overlaying the sternum and the deep fascia is
just above the periosteum of the sternum.

For the most part there is just skin and subcut tissue in front of the
sternum. These tissues overlying the sternum are very thin in most people.

And so it is nonsensical to distinguish superficial from deep based on this
definition in my view

I don’t think that most surgeons put a closure layer beneath the skin once
the sternum is wired- it is impossible. Effectively, then, opening or
dehiscence of the incision will expose the fascia. Similarly, I cannot see
that application of a vac can be done to a ‘superficial’ wound as the fascia
will be exposed in these sort of wounds.

I could cope if the definition specified in this case that infection deep to
the deep fascia a deep (or organ space infection); however that is not
what it says.

We are long overdue for a better NHSN SSI definition., esp for sternal
wounds

John

Dr John Ferguson

Director, Infection Prevention & Control, Hunter New England Health
Tel 61 2 4921 4444 | Fax 61 2 4921 4440 | Mob +61 428 885 573 |
john.ferguson@hnehealth.nsw.gov.au | http://www.hicsiganz.org

http://www.health.nsw.gov.au/images/communications/e-signatures/images/NSW-H
ealth-Hunter-New-England-LHD.jpg

Of Glenys Harrington
for sternotomy infections

Hi John,

Whether or not these wounds are superficial or deep depends on the first
part of the definition as to what tissue is involved. This question has to
be answered before progressing to the rest of the definition.

Superficial – Infection occurs within 30 days after any NHSN operative
procedure and involves only skin and subcutaneous tissue of the incision

Deep – Infection occurs within 30 or 90 days after the NHSN operative
procedure and involves deep soft tissues of the incision (e.g., fascial and
muscle layers)

If only skin and subcutaneous tissue are involved it meets the superficial
definition as from your description c below is met and, Im assuming that
the patient had at least 1 of the sign or symptom below.

patient has at least 1 of the following:

a. purulent drainage from the superficial incision

b. organsims isolated from an aseptically-obtained culture of fluid or
tissue from the superficial incision

c. superficial incision that is deliberately opened by a surgeon and is
culture-positive or not cultured

and

patient has at least one of the following signs or symptoms of infection:
pain or tenderness; localized swelling; redness; or heat. A culture negative
finding does not meet this criterion

d. diagnosis of superficial incisional SSI by the surgeon or attending
physician

If deep soft tissues (e.g., fascial and muscle layers) are involved it will
meet the deep definition as from your description b below has been met and
Im assuming that the patient has at least 1 of the sign or symptom below.

patient has at least one of the following:

a. purulent drainage from the deep incision

b. a deep incision that spontaneously dehisces or is deliberately opened by
a surgeon and is culture- positive or not cultured

and

patient has at least one of the following signs or symptoms: fever (>38C);
localized pain or tenderness. A culture-negative finding does not meet this
criterion.

c. an abscess or other evidence of infection involving the deep incision is
found on direct examination, during invasive procedure, or by
histopathologic examination or imaging test.

d. diagnosis of a deep incisional SSI by a surgeon or attending physician.

Hence in the first instance you need to know what level the surgeon has
opened these wounds too as VACs can be used on superficial or deep would
infections.

Just on organ space infections these wounds as described would not be
considered an organ space infection as such infections exclude the skin
incision, fascia, or muscle layers, that is opened or manipulated during the
operative procedure (i.e. the incisional wound is not involved at all). In
this surgical setting an organ space infection would be something like
osteomyelitis of the sternum without surgical incision/wound involvement.

I use a definition checklist (i.e. it either meets or does not meet the
criteria) when training staff in the interpretation of the definitions for
surveillance purposes.

Can send a copy if you like.

Regards

Glenys

Glenys Harrington

Consultant

Infection Control Consultancy (ICC)

PO Box 5202

Middle Park

Victoria, 3206

Australia

H: +61 3 96902216

M: +61 404 816 434

infexion@ozemail.com.au

ABN 47533508426

Of John Ferguson
infection definition for sternotomy infections

Dear All

Would appreciate advice on interpretation of the definition (below)

In two sternotomy cases, there has been prolonged ooze post op (several
days) and the surgeon concerned has opened the wound on the ward and then
instituted vac dressings

The cases required prolonged nursing management but did not come to formal
debridement or removal of sternal wires etc. CT scans did not show
retrosternal collections (ie not organ space infection)

In my view, this constitutes a ‘deep’ wound infection. What would others
say?

Our other surgeons would have usually taken such cases to theatre and
performed open debridement

in one case the culture grew Serratia

in the other, culture was no growth; in that case, the determination rests
then on whether we had ‘purulent drainage’ observed from the ‘deep incision’

it does beg the question as to how one gauges from what level the drainage
is coming fron and also whether one should use an objective measure for what
is purulent etc!

criterion b under superficial is also problematic – how does one ever get
‘aseptically-obtained’ samples from a superficial incision? wound swabs
presumably not ok but I would guess are used

Would be very interested to know of how people teach surveillance staff to
apply the NHSN definition, esp for sternotomies , where essentially the
superficial wound is extremely close to the deep sternal structure , and
also for prosthetic joints where similar problems of distinguishing the
depth of infection arise

thanks

John

Dr John Ferguson
Director, Infection Prevention & Control, Hunter New England Health

Locked Bag 1, Newcastle Mail Centre, NSW 2310
Tel 61 2 4921 4444 | Fax 61 2 4921 4440 | Mob +61 428 885 573 |
john.ferguson@hnehealth.nsw.gov.au | http://www.hicsiganz.org

http://www.health.nsw.gov.au/images/communications/e-signatures/images/NSW-H
ealth-Hunter-New-England-LHD.jpg

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