[Table of Contents]

Canada Communicable Disease Report - Supplement
Volume: 23S8
December 1997

INFECTION CONTROL GUIDELINES

Preventing Infections Associated with Indwelling Intravascular Access Devices

4. Summary of Novel Concepts in this Document

1. Strength of available evidence

The available research evidence upon which guidelines may be based is limited by the setting in which the research was conducted as well as by the study methodology. In establishing guidelines, extrapolations of data must often be made from studies in different settings. The guidelines presented in this document aim to provide: 1) a conservative interpretation of available evidence, and 2) practical and relevant advice to the Canadian health care practitioner. Many of the published studies were conducted from a perspective of maximizing efficacy or effectiveness at any cost and recommend practices and materials associated with the lowest risk of infection.

Cost-effectiveness and cost-benefit comparisons have different perspectives, and frequently there are insufficient data to identify the strategy associated with lowest cost for a given level of risk or benefit. The reader should take these different perspectives into consideration when reviewing the guidelines. Whenever pertinent studies are available supporting a specific strategy that optimizes (but not necessarily maximizes) efficacy and cost, they will be discussed with respect to the relevance of the recommendation.

2. Benchmarking and surveillance as management tools

This document recognizes the limitations of published data and recommends that individual organizations base their decisions on how to apply the guidelines not only on published data but also on their own infection surveillance data. Those organizations achieving and maintaining low infection rates relative to other similar ones may wish to choose more liberal practices. Those with relatively high infection rates should implement conservative practices until acceptable rates are achieved. Sound epidemiologic judgement is required to determine which interventions and options are most likely to have an impact on a given infection problem.

3. New developments and controversies

The recommendations in this document depart from previous LCDC guidelines on a number of topics. In addition to the use of an evidence-based approach, the topics for which major changes have been recommended include the following:

Site selection

On the basis of results of observational studies and a prospective randomized trial, these guidelines no longer advise against using lower extremity sites.

Transparent dressings for central and arterial lines

There is no evidence to suggest that transparent semipermeable dressings (see Appendix III for glossary) reduce the risk of infection. Two prospective randomized trials have shown an increased risk of both local infection and catheter-associated bacteremia associated with such dressings. These findings, however, have not been replicated in other trials. A recent meta-analysis reported an increased risk of local catheter infection associated with transparent dressings and a trend (but not achieving statistical evidence) towards an increased risk of bacteremia for central catheters. A recommendation supporting the use of transparent semipermeable dressings for central catheters cannot be made.

Routine catheter replacement

Several guidelines recommend replacing central arterial line catheters at 3- to 4-day intervals. Studies show that the cumulative incidence (see Appendix III) rises such that risk of infection is two to three times higher around the fourth day as compared with the first day. However, replacing catheters at new sites (as opposed to discontinuing use of a central arterial line) is beneficial only if the risk of leaving a line indwelling for an additional 24-hour period (incidence density) rises as days accumulate. Recent prospective randomized studies suggest that cumulative incidence, but not incidence density, rises, i.e., the risk for each 24-hour interval may be constant. Thus, this guideline places greater emphasis on discontinuing rather than relocating central arterial catheters.

The incidence density rate of infection associated with peripheral sites in hospitalized adults is known to rise sharply on the third day. Three days has therefore been established as the maximum length of time to use peripheral intravascular lines. More recent studies of children and lines used for intermittent infusions, and of newer catheter materials suggest that longer periods may be safe. However, the sample size and number of studies are too small to document adequately the equivalent safety for longer periods. A recent consensus meeting on home IV therapy suggested 3 days as a lower limit (5 as a suggested upper limit but as required in cases of difficult access) for peripheral site change intervals⁽⁹⁾. This guideline retains 3 days as the upper limit for peripheral sites in all settings, but recognizes the need for further research.

Duration of use of infusion fluids

When suitably low rates of IV-associated infection are achieved, frequent changes of infusion fluids may contribute more to risk of contamination than to control of infection. With the exception of blood, blood components, lipid emulsions, and medications with limited stability, infusion fluids should generally be changed at 72 hours, the same period as for administration sets.

[Previous] [Table of Contents] [Next]