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Canada Communicable Disease Report
- Supplement
Volume: 23S8
December 1997
INFECTION CONTROL GUIDELINES
Preventing Infections Associated with Indwelling Intravascular
Access Devices
Insertion Site Care, Including Dressing and Site
Change Intervals
Heavy colonization of insertion sites is a well- documented risk factor
for infections associated with indwelling devices(2,4). Site
dressing is advocated to protect the open wound from contamination. One
study found 10-fold more bacteria colonizing uncovered skin and 100-fold
more bacteria colonizing skin occluded by an impermeable dressing compared
with skin covered by any of several transparent semipermeable dressings
or gauze(59). Few studies have specifically addressed the optimal
frequency of dressing changes for catheters. However, several studies
have addressed the issue of the type of dressing material and its influence
on cutaneous flora(59-62).
Several studies have found increased bacterial colonization in warm,
moist, occluded sites under transparent semipermeable (both conventional
and the newer, highly permeable) dressings(61,63,64). However,
these studies must be interpreted carefully with respect to potentially
confounding variables such as dampness persisting under the dressing and
differences in the relative permeability of the dressings(60,64).
It should also be emphasized that a positive skin or cannula culture is
a surrogate marker for clinical infection and that the risk of clinical
infection is greater in patients with central as opposed to peripheral
catheters. Some semipermeable transparent dressings have been associated
with an increased risk of infection(60-62). Compared with simple
gauze dressings, transparent semipermeable dressings are more expensive
but permit easy inspection of the site, stabilize the catheter, may offer
an advantage to patients who are mobile, and have been left in place for
up to 7 days(2).
Antimicrobial ointments have been advocated for site care because of
their theoretical advantage in suppressing microbial growth at the insertion
site. There is no epidemiologic evidence to suggest that antimicrobial
ointments are beneficial for short-term peripheral venous sites. Studies
of long-term arterial or central line sites are confounded by changes
in practice (e.g., decreasing use of cut-downs) and catheter materials,
and have produced conflicting results. Increased cost and the potential
to promote the emergence of drug-resistant organisms and colonization
with yeasts are factors that also discourage the use of such ointments.
The cumulative incidence of infection rises with time. In a study of
peripheral venous lines in adults, the risk associated with each additional
24-hour increment of use (incidence density) also increased with time,
so risk can be reduced by replacing lines at new sites every 48-72 hours(65).
A similar increase in incidence density has not been documented with peripheral
venous or arterial lines in children(66-68) or with central
venous lines(69,70). Therefore, it is not prudent to replace
these lines on a routine basis. It has been suggested that pulmonary arterial
lines in intensive care units be replaced every 4 days because of increased
risk of infection(59), but one prospective study does not support
this practice(70). Studies suggest that incidence density may
rise during the first few days, but then declines and remains low. Unlike
a study that used a historical comparison group(71), prospective
studies show that routine cannula replacement over a guide wire fails
to decrease the risk of infection(70,72,73).
RECOMMENDATIONS
All Lines
- Patients with intravascular devices should be evaluated at least daily
for evidence of infectious complications. This evaluation may include
gentle palpation of the insertion site through the intact dressing or
direct observation, as appropriate for the type of device. (Category
B; Grade III)
- If a patient has unexplained fever, or pain or tenderness at an insertion
site, or if a patient cannot communicate, then the intravascular site
should be inspected visually. (Category B; Grade III)
Peripheral Venous Lines
- Antimicrobial ointments are of no proven benefit and should not be
applied at the time of dressing changes(2). (Category
D; Grade II)
- A sterile gauze dressing should be used and, unless the dressing
or the skin surrounding the entry site becomes wet or soiled, may be
left in place until the catheter is removed. Alternatively, a transparent
semipermeable dressing (low or high permeability) may be used since
the risk of bacteremia is extremely low with peripheral IV lines(63).
(Category A; Grade I)
- For adults in hospital settings, steel or plastic cannulae may be
left in place for up to 72 hours(2,65). Unless there are
signs of inflammation, peripheral venous lines in children need not
necessarily be changed as long as they remain functional(66,67).
(Category A; Grade II)
- There are insufficient data to make definitive recommendations for
longer periods for lines used for intermittent infusion(74)
or in home care settings(75). (Category C)
Arterial Lines
-
There are insufficient data on which to base a recommendation concerning
use of an antimicrobial ointment at the time of dressing changes.
(Category C)
-
A sterile gauze dressing should be used. A transparent semipermeable
(low or high permeability) dressing may be considered for peripheral
arterial lines, but gauze may be preferable for patients who are profoundly
diaphoretic or who have very fragile skin. The dressing should be
changed if skin at the entry site is wet; otherwise, an optimal interval
for routine dressing changes is unknown. (Category B; Grade III)
-
For adults, peripheral arterial catheters may be left in place for
up to 6 days(76). Peripheral arterial catheters may be
left in place for an even longer duration in pediatric patients(68).
The upper limit for pediatrics is not yet established. (Category
B; Grade II)
Central Venous Lines (including PICC, central hemodialysis
lines and central pulmonary arterial catheters) and Midline Catheters
-
Application of povidone-iodine ointment at the time of dressing changes(57)
may be considered as a preventive measure. (Category B; Grade II)
-
Sterile gauze dressings should be used for lines inserted at subclavian
and internal jugular central sites(61). (Category A;
Grade I)
-
There are currently insufficient data to recommend the optimal choice
of dressings for lines placed at other sites, including those for
PICC (see Appendix III) and midline catheters. (Category C)
-
By convention, gauze dressings have been changed every 2 to 3 days,
but the optimal duration between dressing changes is unknown. Gauze
dressings may be left in place for a longer duration but should be
changed whenever they are soiled or wet. (Category C)
-
Central venous lines used for total parenteral nutrition or long-term
antimicrobial or antineoplastic chemotherapy and hemodialysis may
be left in place as long as they remain functional, unless they appear
to be a source of infection. (Category B; Grade III)
-
A catheter should not be changed over a guide wire if infection is
suspected. However, a change over a guide wire may be done in the
case of malfunction(70). (Category B; Grade I)
-
Pulmonary arterial catheters may be left in place for up to 4 days(58).
If it is essential to continue pulmonary arterial catheter monitoring
beyond the fourth day, there are four potential options (Category
C):
-
Leave the catheter in place, assuming that cumulative risk of
infection will continue to multiply at a constant rate(70).
-
Remove the catheter and place a new catheter at a new site, to
gain another 4 days of presumed low risk(58).
-
Replace the catheter over a guide wire and culture the old catheter.
If the old catheter is shown to be infected, remove the new catheter
from the infected site; if the old catheter is not infected, the
new catheter may be left in place(58).
-
Use catheters or catheter cuffs that incorporate antimicrobial
compounds(29,30).
Totally Implantable Devices
-
The needle may be removed at the end of each infusion or left in
place as an intermittent heparinized lock. Needles should be changed
frequently enough to prevent skin breakdown. This should be at least
every 7 days(77). (Category B; Grade III)
-
The needle should be secured and covered with a sterile dressing.
There are insufficient data to recommend specific site care and dressing
change protocols. (Category C)
Umbilical Lines
- The relation between duration of umbilical arterial and venous catheterization
and catheter-related sepsis has not been established(78).
No recommendation is made regarding time limits for umbilical lines.
(Category C)
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