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Centre for Applied Nursing Research,
Liverpool NSW

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Systematic Review
Central Line Dressing Type and Frequency


CPRN SYSTEMATIC REVIEW


 Reviewer ID CPRN
 Review number. 0001
 Full title. How frequently and what type of central line dressing in hospital inpatients prevent complications?
 Short title. Central line dressings
 Names of reviewers CPRN group one
 Date commenced. 18 September 1997
 Date last edited 28 April 1998
 Date last updated 20 January 1998
 Contact name: Sushila Agnihotri or Jenny Morris
 Contact address Centre for Applied Nursing Research
Liverpool Health Service
PO Box 103
Liverpool 2170
 Telephone 02 9828 3275
 Fax 02 9828 3273
Email CPRN@hotmail.com
 Source of Support Dr. Maree Johnson,
Professor of Nursing
CANR South Western Sydney Health Service


Links within this web page:

Background

Objectives

Criteria

Search strategy

Method

Factors that varied among studies

Summary

List of tables

References




BACKGROUND


The use of Central Venous Catheters (CVC) for long term nutrition, administration of blood products, antibiotic therapy and haemodynamic monitoring has increased. Catheter Related Septicaemia (CRS) is the most life threatening complication of infusion therapy (Maki & Ringer, 1987). 10-14% of catheter sites become infected with a reported CRS frequency of 3-7% (Babycos et al, 1990, Moro et al, 1994). Factors associated with an increased risk of CVC infection include severity of the patient's underlying illness, whether the catheter is single lumen or multiple lumen, the use of the catheter for total parenteral nutrition and the placement of the catheter in the femoral site compared with jugular or subclavian placement (Hoffman et al., 1992). Other identified risk factors include the method of skin disinfection prior to catheter insertion, the type of dressing material used, the frequency of the dressing change, the frequency of catheter replacement, and the use of antibacterial ointment at the catheter insertion site (Hoffman et al., 1992; Prager et al., 1984).


Type of dressings


A CVC dressing is important as it provides a barrier impermeable to water and bacteria (Shivnan et al., 1991), protects the catheter site from external contamination, secures the CVC to prevent dislodgment, and discourages bacterial proliferation near the insertion site (Treston-Aurand et al., 1997). The type of dressing applied to the catheter site can influence the incidence of catheter related infections (Moro et al., 1992; Lucas et al., 1992; Richet et al.; 1990). The most common type of dressings used are transparent dressings and gauze-tape dressings.


Transparent dressings are widely used as they not only provide an occlusive dressing that enables continuous inspection of the central line site, but also reduce the number of weekly dressings required. Transparent dressings are also more comfortable (Wille et al., 1993) and allow patients to continue their everyday activities. Nursing time in dressing change is minimised, both for the time taken per dressing and also for the frequency of the dressing change (Shivnan et al., 1991). Whilst transparent dressings have been shown to be cost effective in bone marrow transplant patients-$27.96 for transparent dressing compared to $87.08 for gauze dressing (Brandt, DePalma, Irwin et al.; 1996), the disadvantages are that accumulated blood, sweat and exudate under the dressing can be an excellent culture medium for organisms (Reynolds et al., 1997:26). Several studies have raised the possibility that transparent dressings may increase the risk of catheter-related infections (CRI) (Callahan et al., 1987; Conly et al.; 1989, Hoffmann et al., 1992; Petrosino et al., 1988; Powell et al., 1982; Richet et al., 1990), but prospective randomised trials have not confirmed that transparent dressings are associated with an increase in catheter-related blood stream infection (Young et al., 1988; Palidar et al., 1982; Nehme & Trigger, 1984; Andersen et al., 1986).The permeability of the transparent dressing can be an important factor as porousness of the dressing material can result in a less favorable environment for potential pathogens and reduce the risk of CVC related sepsis (Reynolds et al., 1997:26).


Hoffman et al. (1992) using a meta-analysis approach compared the complication risks of transparent and gauze dressings for central and peripheral venous catheters and found no significant relationship between dressing type and the incidence of phlebitis, bacterial infiltration and skin colonization. However, there was a significant relationship between catheter tip colonization and dressing type. The use of transparent dressings increased the relative risk of catheter tip colonization by 53% in central and peripheral catheters. Catheter tip infection is an excellent prediction of bacteremia and sepsis (Hoffman et al, 1992: 2074).

Frequency of dressing change


The frequency of CVC dressing change can vary from daily to weekly and is generally dependent on the material type of the dressing. Gauze-tape dressings tend to be changed more frequently, either daily or second daily, whilst transparent dressings tend to be changed once or twice a week (Less frequently changed transparent dressing is comparable in terms of associated CVC related infection rates.) (Lawson et al., 1986; Nehme & Trigger, 1984; Palidar et al., 1982; Vasquez & Janard 1984; Young et al., 1988). The type and frequency of dressing change plays an important role in the cost of the vascular dressing.
The Centers for Disease Control (CDC) and Prevention's Guidelines for Prevention of Intravascular Device-Related Infections for CVC do not recommend any specific dressing type or the frequency of the dressing change. CDC recommends replacing the dressing for peripheral venous catheters and central venous catheters when the catheter is changed or when the dressing becomes damp, loosened, or soiled or when inspection of the site is necessary (Centers for Disease Control Guidelines for Intra Vascular Devices, March 1997).
There are no clear guidelines with regard to the most suitable type of dressing to use and the frequency of dressing change that is most effective. This review aims to assess research studies to evaluate if dressings can affect the incidence of complications in patients with CVC lines and to identify the most suitable central line dressing and the frequency of the dressing change necessary.



OBJECTIVES


The objectives of this review are to determine:

i. the most effective type of central line dressing to use and

ii. the frequency of the dressing change that is necessary in all hospital inpatients.


The outcomes of interest are:

i. mortality

ii. local and systemic infection

iii. catheter displacement

iv. thrombus formation

v. catheter breakage or blockage

vi. skin irritation or allergic reaction that is a direct result of the dressing type and/or frequency of the dressing change.



CRITERIA FOR CONSIDERING STUDIES FOR THIS REVIEW


This review assesses research studies on all central venous catheter sites:

i. with a sample population of 30 or more in hospital subjects

ii. that either evaluate a dressing material or compare types of dressing materials

iii. and/or the frequency of the dressing change with regards to the above identified outcomes.


Definition of CVC

A CVC is defined as any non tunneled percutaneously inserted catheter with the catheter tip in the superior vena cava. This includes CVCs inserted into the internal jugular vein, the subclavian vein, the femoral vein and Peripherally Inserted Central Catheters (PICC).

Types of participants

Inclusions

All age participants, both male and female treated in a hospital setting with a central venous catheter insitu are included in this study. No participants with any predisposing health risk factors are excluded. All CVC compositions, single and multiple lumen whether antiseptic or antibiotic bonded, tunneled and non-tunneled catheters, in any insertion site are included. CVC for short term and long term vascular access usage to administer IV fluids, medications, blood products, parenteral nutrition and haemodynamic monitoring are included.

Exclusions

Arterial and Pulmonary catheters

Articles that do not specifically identify catheters as being CVC

Non specific intravenous lines or peripheral lines

Articles that do not specifically evaluate dressing type or frequency of the dressing change

Articles that do not assess outcomes of local or systemic infection, catheter displacement or reaction to the dressing

Outpatient and hospital in the home population

Studies that refer to dressing technique and /or catheter placement site

Studies that are a review or discussion of the general care of central venous catheter sites.

Types of interventions

This review assesses evaluations and/or comparisons of all types of dressing material and all frequencies of dressing change for any central venous catheter site in any age in-hospital population.

Types of outcomes

The main outcomes of interest are complications that are caused as a direct result of the type of dressing and/ or the frequency of the dressing change. The identified complications are mortality, local or catheter related infection, systemic infection or catheter related sepsis, catheter displacement, thrombus formation, catheter breakage or blockage, skin irritation or allergic reaction to the dressing.

Definitions of outcomes

Exit site infection

identified by any one or more of the following symptoms - erythema, tenderness, skin necrosis, phlebitis, swelling, exudate including purulence, pain.

Catheter Related Infection (CRI )

identified by positive quantitative or semiquantitative culture of the catheter >15 colony forming units.

Catheter Related Sepsis (CRS)

identified by signs and symptoms consistent with:

i. infection (including defervescence or clinical signs of infection prior to removal of catheter) and fungaemia or bacteraemia or

ii. a positive catheter tip culture or fever and bacteremia or

iii. fungemia in the absence of an exit site or tunnel infection.

Bacteraemia

Identified when there is a positive blood culture from the central venous catheter.

Complications due to catheter material, catheter size, site of catheter placement and composition of the intravenous fluid are acknowledged as being identified in the literature but have not been analysed separately in this review.

Types of studies

Any research study with a sample population of over 30, that evaluates and/or compares studies of one or more dressings type, and/or frequency of dressing change for a central venous catheter site.


SEARCH STRATEGY FOR IDENTIFICATION OF STUDIES

The search was restricted to English language articles that were published after 1980. The search strategy and the search process of the identification of articles was documented.

Search terms used

vascular catheters, central venous catheters, central venous therapy, peripherally inserted central catheters, parenteral nutrition, wound infection, dressing, dressings, occlusive dressings, biological dressings, transparent dressings, bandages and dressings, infection control, complications, and Boolean combinations of the above.

Electronic database search

The electronic databases searched were Medline 1981 - September 1997, CINAHL 1982 - July 1997, HealthStar 1975 - September 1997, and the Cochrane Library 1997 Issue 3. All abstracts and presentations identified were followed up by searching for the authors collectively as well as searching each cited author, individually.

Hand search

The CINAHL and Medline journal index were searched to identify journals that were not catalogued in these databases.

Full text hand searches of the Journal of Intravenous Nursing January 1994 - August 1997, Intravenous Connections - NSW Nurses Intravenous Society January 1996 - September 1997, Australian Clinical Review 1981 - 1993 and Journal of Critical Care 1986 - August 1997 were conducted.

Reference list search

Potential articles that satisfied the Inclusion/Exclusion criteria were retrieved. All reference lists of the potential articles identified were searched. Papers published prior to 1980 were identified, excluded, and not retrieved.

The reference list of 434 articles from the Guidelines for Prevention of Intravascular Device-Related Infections from the Centers for Disease Control and Prevention, Atlanta, Georgia, March 1997 was searched and 2 new articles were retrieved.

Unpublished articles

Two 1997 conference presentations were identified. The authors were contacted. No data is available till publication early next year.

Other

Expert opinion and guidance was sought from the Clinical Nurse Consultant for Central lines, Tim Spencer, Liverpool Health Services, South West Sydney Area Health Service. He commented that he felt that the sources searched were comprehensive and could offer no further suggestions.

Towards the end of the search process, searching of the reference list of the articles retrieved identified repeat articles and no new articles were being identified. This indicated to us that the search process was comprehensive and there were no new articles left to retrieve.


METHOD OF THE REVIEW

Data abstraction:

In all a total of 146 possible articles was identified. Forty-four articles were repeated either in more than one electronic database or in the reference lists of identified articles. Thirty-two articles were not CVC or did not assess dressing type or dressing frequency. A total of seventy articles were retrieved. When the Inclusion/Exclusion criteria were applied to the title and abstract, thirty-seven potential studies were identified. (One of these was a meta analysis of transparent polyurethane film as an intravenous catheter dressing.) Sixteen of these articles were subsequently excluded. The reasons for exclusion were: not evaluating dressings, not evaluating identified complications, includes arterial catheters, peripheral IV catheters, dressing type identified only as regular.

The search strategy, search process, Inclusion/Exclusion criteria, Exclusion of Potential Studies and the Data Abstraction forms were developed by the CPRN, trialed, and refined. Two reviewers of the Clinical Practice Review Network independently assessed each article to be included in the review by applying the Inclusion/Exclusion criteria. Following the inclusion of the article for review, data extraction of each article was conducted independently by two reviewers. The reviewers were not blinded. Any disagreements were resolved by the project leaders.

Description of studies (see Table 1)

Twenty-one studies were identified. One cohort study (Moro, M., Lepri, V. et al. 1994), two experimental studies (Brandt, B., DePalma, J. et al, 1996; Shivnan, J., McGuire, D. et al 1991), one quasi experimental study (Freiberger, D., Bryant, J. et al 1995) and one clinical trial study (Willie, J., Albas, B. et al. 1993) were identified. Thirteen of the studies were case series of comparative studies of two or more dressing types and three studies evaluated a single dressing type. The study sizes ranged from 32 to 3931 participants. The age range of eighteen studies was from one day to 91 years of age. Three studies did not identify the age range of the participants. Sixteen studies evaluated both dressing type and frequency of dressing change. Five studies evaluated dressing type with the frequency of dressing change not identified.

The type of patients identified were medical/ surgical (10 studies), total parenteral nutrition (6 studies), bone marrow transplant (3 studies), one chemotherapy, and one study did not describe the patients involved.
In six studies central lines were used for TPN therapy, in three studies for monitoring and antibiotic therapy and in one study for chemotherapy. Eleven studies did not disclose the use of the CVC.

The location of the central lines were subclavian and jugular (5 studies), subclavian (4 studies), jugular (1 study), subclavian and cubital (1 study), subclavian, jugular and cubital (1 study), subclavian, jugular and femoral (1 study). Eight studies did not identify the location of the CVC.

The studies were conducted at tertiary teaching hospitals in twelve studies, two tertiary teaching hospitals and five large non teaching hospitals in one study, district hospital in one study, and seven were not identified

Table 1: Characteristics of included studies

 

 Methodological quality of included studies

The method of allocation of participants to seven studies was random with participants in one study assigned consecutively, in two studies assigned sequentially, in three studies assigned by hospital number and in one study assigned by date of birth. The method of random allocation in eight studies was not described. One study did a retrospective audit of medical records, four studies included all participants and one study did not identify the method of allocation of participants to the study.

The attrition rate identified in five studies was 5 out of 79 participants, 12 out of 32 participants, 22 out of 145 participants, 0 out of 365 participants and 61 out of 104 participants. Fifteen studies did not identify the attrition rate. None of the studies described any method of blinding.

Quality of Evidence (see Table 2 and Figure 1)

To assess the quality of the evidence, the studies were scored using weighted variables. The best possible score was 18 and the worst possible score was 46. The mean score of the studies was 29.67, with a median score of 30, a mode score of 29, and a standard deviation of 3.76. Four studies scored 27 or under with twelve studies scoring between 28 to 30 and five studies scored over 30.

Table 2. & Figure 1. Weighting of included studies


FACTORS THAT VARIED AMONG STUDIES

There were several factors that varied amongst the twenty one studies.

Location of CVC

The CVC sites identified were subclavian in four studies, jugular in one study, subclavian and jugular in five studies, subclavian and cubital in one study, subclavian, jugular and cubital in one study and subclavian, jugular and femoral in one study. Eight studies did not identify the location of the CVC.

Clinical use of the CVC

The CVC lines were used for the following purposes-TPN in six studies; monitoring, antibiotic therapy and TPN in three studies; chemotherapy in one study; and eleven studies did not identify the reason for use of the CVC line.

Insertion technique and skin disinfection

13 CVCs were inserted by doctors, with 4 CVCs inserted in the operating theatres by an anaesthetist and 2 CVCs inserted either in the operating room or the intensive care unit. Nine studies did not identify the person insertinging the CVC. The technique used to insert the CVC was aseptic in eleven studies, protocol in two studies, sterile gloves in one study, and not identified in seven studies.

The disinfection solutions in inserting the CVC were povidone iodine in three studies, acetone alcohol and povidone iodine in two studies, iodine and povidone iodine in one study, iodine in two studies, iodine and alcohol in one study, iodine and chlorhexidine 70% in one study, 0.5% aqueous chlorhexidine in one study.

Nine studies did not identify the skin disinfection solution used at insertion of the CVC.

Regimen/technique for dressing change

The disinfection solutions used were acetone alcohol and povidone iodine in seven studies, povidone or Hibiclens in one study, acetone alcohol and aqueous chlorhexidine gluconate 0.5% in one study, aqueous chlorhexidine gluconate 0.5% in one study, 70% alcohol in one study, 70% alcohol and 2% chlorhexidine in one study, and hydrogen peroxide and povidone iodine in one study. In one study the dressing solutions used were described as published standard guidelines (which were CDC guidelines), and in seven studies it was not identified.

Health status of patient

The predisposing health factors were carcinoma in five studies; carcinoma, cardiovascular disease and gastrointestinal disease in 2 studies; gastrointestinal disease in one study; and major surgery in one study. In one study the patients were immunosuppressed. Eleven studies did not identify the predisposing health status of the patients.

Bacteriological methods used to confirm infection

The bacteriological methods used to confirm local and systemic infection of the CVC were one or more of the following: blood sample from the CVC, skin culture of insertion site, blood sample from peripheral site and CVC tip culture.

`Blood sample from the CVC

Samples were taken from all patients in nine studies, patients suspected with CRI in two studies, and not identified in ten studies.

Skin culture of insertion site

The skin culture of the CVC site was performed in thirteen studies-in all patient in ten studies, in patients with suspected infection in one study, in 75 out of 103 patients in one study due to laboratory difficulties, and not identified in one study. Skin cultures were done at the time of insertion of the CVC and/or during dressing change and/or at the time of the removal of the CVC. Nine studies did not identify whether skin cultures of the CVC was performed.

Blood sample from peripheral site

Blood samples were taken from another peripheral site in all patients in 6 studies and in patients with suspected CRS in 2 studies. 13 studies did not identify if a blood sample was taken from another peripheral site.

CVC tip culture

The CVC tip was cultured for all patients in 13 studies, for patients suspected with CRI in 4 studies. 4 studies did not identify if CVC culture tip was performed.

Additional variables that may affect the infection risks associated with CVCs

i.. The duration of catheter use

The duration of catheter use varied from 2 days to 120 days in 12 studies. 9 studies did not identify the duration of CVC use.

ii. The frequency of dressing change

The frequency of dressing change was daily, second daily, three times a week, weekly and every 7 to 10 days. 5 studies did not identify the frequency of dressing change.

iii. The use of antiseptic ointment at the insertion site

7 studies used Betadine ointment at the insertion site of the CVC and 1 study used an antibiotic ointment consisting of bacitracin, neomycin and polymyxin.


SUMMARY OF ANALYSES

Results

Tables 4-19 present the results of the data abstraction.


Discussion

Limitations of the review process

The limitations of the review process were that only English language and published articles were used. The search included articles from 1980 onwards as, prior to this period, there was little use of and information on the use of central lines. The time frame of the project limited the hand searching. Articles that were identified for the review, but which did not provide adequate information, were followed up with search of author names that appeared on the article as well as search of individual author names. No authors were contacted directly. All abstracts and presentations identified were followed up by searching for the authors collectively as well as searching each cited author individually.

Limitations of the studies

Type of studies identified

No RCT or CCT studies were identified. The 21 studies used in this Systematic Review were:

1 cohort study (Moro, 1994), 2 experimental studies (Brandt ,1996; Shivnan, 1991), 1 quasi experimental study (Freiberger, 1992), 1 clinical trial (Wille, 1993), 13 case series (Reynolds, 1997; Treston-Aurand, 1997; Maki ,1993; Conly, 1989; Young, 1988; Lawson, 1986; Andersen, 1986; Wheeler, 1986; Powell, 1985; Prager, 1984; Nehme, 1984; Palidar, 1982; and Powell, 1982) and 3 evaluation studies (Taylor, 1996; Engervall, 1995; and Vazquez, 1984) were identified.

Weighting of the studies

No suitable scale to evaluate the quality of the studies was identified. The CPRN team designed a scale based on Ciliska et.al 's (1996) method of evaluation of using weighted variables. Important factors contributing to the complication rates in CVCs were identified. The variables used were: type of study, allocation to the study, sample size, predisposing health status of the participants, type and site of CL, insertion technique, the use of the CL, duration the CL was in situ, the reason for removal of the CL, dressing frequency, attrition rate, antibiotic therapy and the bacteriological method used to identify local and systemic infection. The studies were then assessed using this weighted scale. With a best score of 18 and a worst score of 46, four studies scored from 22 to 27 inclusive; and the remaining seventeen studies scored from 28 to 36. The studies were graded using the following scale:

18-27 good quality, 28-37 medium quality, 38+ poor quality.

This resulted in four good quality studies; 17 studies of medium quality, and no poor quality studies were identified.

CVC related infections

There are numerous factors associated with CVC related infections and the role played by specific factors in increasing the risk of infection is not entirely clear.

Skin colonization and CRI

Skin colonization is a major determinant for endemic CRI and heavy colonization of the insertion site is highly predictive of CRS. Septicaemias begin with invasion of the transcutaneous insertion tract by microorganisms from the patient's skin flora (Maki & Ringer 1993, Nehme & Trigger 1984). Microbial colonization of the CVC is the most frequent factor limiting their prolonged used and is attributed to skin organisms that either migrate down fibrin sleeves or are introduced during placement of the CVC (Prager & Silva 1984).

Conly et al. (1989) analyzed 20 variables to predict the occurrence of CRI or CRS using stepwise multiple logistic regression analysis. Cutaneous colonization at the insertion site of > 103 cfu/ml (relative risk 13.16) and difficulty of insertion (relative risk 5.39) were significant factors for CRI. Moro et al. (1994), also using logistic regression, confirmed the importance of skin colonization and hub colonization in causing CRI. Other factors identified as being responsible for skin colonization are age, jugular insertion site, duration of the CVC catheterization and the use of transparent dressing.

Influence of dressing type on CRI

Several studies have raised the possibility that transparent dressings may increase the risk of CRI. Conly et al. (1989) found significantly greater skin colonization after 48 hours of CL insertion in the transparent versus gauze dressing (p < 0.009). They suggest that transparent dressings are associated with significantly increased rates of insertion site colonization, local catheter related infection, and systemic catheter related sepsis in patients with long term CVC after finding that local CRI in the gauze dressing group was less than in the transparent dressing group (p <0.002).

Andersen et al., (1986) [good quality] in their non-randomized study comparing gauze dressings with transparent (Opsite) dressings, found more phlebitis and catheter tip infection when a transparent dressing was used. Differences in the frequency of positive tip culture, positive skin culture and clinical signs of local infection at the skin puncture site were significant (p < 0.05) between the gauze dressing group (5/75) and the transparent dressing group (15/60). The mean function time of the catheters with positive tip or skin culture was significantly lower in the transparent dressing group than in the gauze dressing group (p < 0.001).

Treston-Aurand and Olmsted (1997) [medium quality], in their non-randomized retrospective study, demonstrated that the use of transparent or tape and gauze dressings resulted in fewer CRIs (p < 0.001) than Highly Permeable Transparent Dressing (HPTD).

Vazquez and Jarrard (1984) [medium quality] claim that transparent dressings inhibit bacterial growth, but have failed to carefully evaluate bacterial growth beneath the dressings in high risk patients over an extended period of time.
Maki and Ringer's (1993) [medium quality] prospective randomized study found the mean colonization of catheter exit sites and local CRI was higher in the transparent dressing group than in the gauze dressing group but the results were not statistically significant.

Shivnan et al's (1991) [good quality] prospective randomized study found fewer infections with gauze dressings. Only a small portion (4%) developed exit site infection or CRS even though 36% had a positive blood culture. The limitation of this study was that it was not large enough (n = 98) to allow analysis of differences between subgroups, and therefore we cannot conclude that the low incidence of CRS is related to the type of dressing used.

Powell and Regan (1982) [medium quality] in their prospective randomized study compared transparent versus gauze dressings for TPN and demonstrated a consistent but not significant increase in CRI in the group receiving transparent dressings.

Brandt et al (1996) [medium quality] and Lawson et al (1986) [medium quality] found no statistical difference in CVC related infection between gauze and transparent dressings.

Hoffman et al (1992) carried out a meta analysis of seven studies (Powell et al., 1982; Andersen et al., 1986; Conly et al., 1989; Maki & Ringer, 1987; Littenberg & Thompson ,1987; and Hoffman et al., 1988) of CVCs and found no significant relationship between dressing type and the incidence of phlebitis, bacterial infiltration and skin colonization but concluded that there was a significant increase in the risk of catheter tip infection when using transparent dressings as opposed to gauze dressings (RR 1.78, 1.38-2.30).

Influence of dressing frequency on CRI

Less frequently changed transparent dressings have been supported in the literature not because of a correlation with a reduction in CRS but mainly due to cost reduction in the overall number of dressings used per CVC site as well as the subsequent reduction in nursing time necessary.

Lawson et al. (1986) [medium quality] compared gauze dressings changed three times a week to transparent dressings changed weekly and found no statistical difference but concluded that cost could be reduced by using transparent dressings.
Nehme and Trigger (1984) [medium quality] compared gauze dressings changed every second day and transparent dressings changed weekly and found no difference in the prevention of CRS but concluded that Opsite was time and cost effective, versatile and easy to apply.

Palidar et al. (1982) [medium quality], in their retrospective non-randomized study comparing gauze dressings changed twice a week and transparent dressings changed once a week, came to the same conclusion.

Shivnan et al (1991) [good quality], whilst finding no difference in CRS rates between gauze dressings and transparent dressings found that nursing times and dressing costs were significantly reduced in the transparent dressing group (p < 0.0001) when compared to the gauze dressing group (p<0.000). Overall patient comfort in the transparent group was reported as p<0.001.

Wheeler et al. (1988) compared gauze dressings changed three times a week to transparent dressings changed once a week and found no statistical difference in infection rates but noted that transparent dressings showed significant time and expense savings and offered superior occlusive protection.

Young et al. (1987) [good quality] compared gauze dressings changed three times a week with transparent dressings changed twice weekly, weekly, and every ten days. They found no significant differences between the groups and recommended the use of transparent dressings changed weekly with a safety margin of 10 days based on savings in cost and nursing time.

Engervall et al. (1995) compared transparent dressings changed once a week to transparent dressings changed twice a week and concluded that twice a week dressing change is superior to once a week dressing change. The once a week group had more positive CVC tip cultures (p < 0.05), more cultures from the exit skin site showing higher numbers of colony forming units (p 0.07) and more gram positive septicaemias (p 0.08).

Effect of antiseptic solution for skin preparation

Two factors associated with infection related phlebitis are the skin preparation and the frequency of the dressing change.

Maki and Ringer1(993) [medium quality] compared the effect of 2% chlorhexidine, 70% alcohol and 2% povidone iodine. The CVCs in the chlorhexidine 2% group, were less likely (p 0.02) to show local CRI on removal than were catheters in the povidone iodine group. Chlorhexidine 2% significantly prevented local CRI (p 0.02) and showed a strong trend towards significant benefit in the prevention of catheter related bacteremia (p 0.18).

Freiberger and Bryant (1992)[medium quality] demonstrated no significant differences in incidence of bacterial growth between dressings groups of Betadine and Tegaderm, Betadine and Gauze, Hibiclens and Tegaderm, Hibiclens and gauze. The limitation was the use of a convenience sample rather than probability sampling and the duration of the study. The sample was not large enough to determine if one dressing was better than the other in decreasing the incidence of infection.

Bacteriological methods

The contamination of an intravenous pathway may be manifested by local infection of the insertion site, septic phlebitis or thrombophlebitis or septicaemia or bacteremia. The methods of diagnosing infection can be semi quantitative or quantitative. Speechley (1986:95) identified the bacteriological methods used to confirm local and systemic infection of the CVC as one or more of the following: catheter lumen flushed through with broth, the catheter tip rolled on blood agar, the CVC lumen cleaned with stilleto and then rolled onto blood agar, the catheter tip cultured in broth, the catheter tip is gram stained, the insertion site is swabbed and blood specimen collected from the CVC site and/or a site different to the CVC. The categories of CVC infection identified and the methods used to diagnose CRI and CRS were different and posed a significant problem in the translation and comparison of results between the studies. The redness of the CVC site is often taken to be an indication of infection but it may not be associated with higher bacterial count but may mean irritation. The insertion site may have bacterial growth even though there is no redness, therefore a culture is the best measure for determining exit site infections (Freiberger & Bryant, 1992). Nine studies in this review did not identify whether exit site colonization of the CVC had been done. Diagnosis of CRI requires a positive catheter tip culture >15 colony forming units. Four studies did not identify if the catheter tip had been cultured. Diagnosis of CRS requires either a positive catheter tip culture or fever and a positive blood culture from the central venous catheter and was not identified in 10 studies.

Conclusions

The numerous differences between patient groups and research design methods indicated that the studies were not similar enough for either comparison or meta-analysis. The numerous variables associated with CVC related infections and the role played by specific factors in increasing the risk of infection is not entirely clear. The evidence was inconclusive to substantiate that any one type of dressing or frequency of dressing change was superior in preventing CVC complications.
The most effective defence mechanism against the introduction of bacteria to the catheter site is sterile technique. Failure to adopt adequate aseptic technique is likely to increase the risk of skin and hub colonization (Moro et al., 1994). A co-relation between localized infection complications and systemic infections was demonstrated by Speechley, 1986. Patients with phlebitis showed an 18 fold risk of septicaemia and 25% of patients with local inflammation developed systemic infection and positive blood cultures. Disinfection of the catheter insertion site and strict dressing protocols are important steps in the prevention of CRI. Conly et al (1989) demonstrated an association between skin colonization and CRS. Shivnan et al. (1991) demonstrated fewer infections with gauze dressings even though positive blood cultures were high. Strict dressing protocol was identified as one of the reasons for the reduced infection rate. Transparent dressings have been advocated as useful in determining the occurrence of CRS by frequent visualization of the catheterization site but this should not be relied upon as inflammation may be due irritation rather than infection.

Implications for practice

Inconclusive evidenceexists as to the effectiveness of any particular type of CVC dressing or frequency of dressing change. Although transparent dressings have been found clinically if not consistently stastically to increase risk of catheter-related infections, the cost implications of reduced frequency of dressings and reduction in nursing time have also played an important part in clinical decision making. The use of the transparent dressing and the potential for shanging every 10 days may be considered. Many studies have used the once per 7 days dressing change; only one study examined the 10 day option, although it was supported. The quality of the evidence is medium to good and does provide clinicians with access to no other source of evidence with some beginning points for decision making. These studies and their implications should be reviewed and debated by clinicians to shape practice. However, it is recommended that strict aseptic techniques for the placement and care of CVC be employed in the care of central line dressings.

Implications for research

More research is needed to identify the effect of dressings on CVC related infections. Literature on the subject of central line infections show a lack of consensus on research methods as well as operational definitions of the terms used. For comparison, interpretation and synthesis of studies, the definition used must clearly convey the intended meaning. Clarification about the bacteriological methods used to identify, skin colonization, CRI and CRS is also necessary.
Duration of the CVC placement as well as host factors have been identified as important factors contributing to CRI. The roles of these important contributing factors should be clearly identified.

All Reviewers

At the recruitment phase, all potential reviewers completed a self assessment of their educational level and skill levels. The average years of nursing experience for all reviewers was 14.707 years. Skill levels on a scale of where 1 = unskilled and 4 = skilled, library catalogue skills was 2.595, computer skills searching the medline and CINAHL database was 2.119, critiquing skills of articles was 2.309 and summarising skills of articles was 2.523.

Hospital Yrs of Experience Library Catalogue Medline CINAHL PreCritique PreSummary
Bowral 13 2 1.5 2.5 2.5
Camden 14.33 2 2 2 2
Campbelltown 16.454 2.181 2 2 2.181
Bankstown 12.333 3 1.9 2.5 2.7
Fairfield 20 2.5 1.5 2 2.5
Liverpool 14.428 2.857 2.571 2.5 2.785
All hospitals 14.7.7 2.595 2.119 2.309 2.523

Who inserted, technique insertion, method of analysis, bacteriological diagnostics
Author Who Inserted Tech of insertion Dress tech Stat analysis Blood CVC Skin culture Blood other Cath tip cult
Anderson anaes aseptic NI Chi, Yates, Wilcoxon all all all all
Brandt NI NI alcoh, PI, PIO Mann Whitney all susp inf all
febrile

all 

Conly OR aseptic CDC guide Chi, Yates
orFishers, Mann Whitney
NI 

dress change, removal 

NI 

distal proximal hub

Engervall OR aseptic 70% ethanol Mann Whitney not all all not all all
Lawson NI NI alcoh, PI, PIO Chi NI NI NI NI
Freiberger OR NI povidone, Hibiclens Chi NI insert removal NI NI
Maki Dr s/ gloves PI or &0% alcoh or 2% chlorhex Chi Fishers NI insert Ni proximal tip, hub infusate
Moro NI aseptic NI Chi NI ? when NI hub
Nehme Dr aseptic alco, povidone Chi susp CRI NI NI all
Palidar Dr sterile alco, povidone NI NI NI NI all
Powell 82 Dr aseptic alcoh, PI, PIO stat NI all NI NI all
Powell 85 NI NI alcoh, PI, PIO stat NI all NI NI all
Prager Dr protocol NI Chi ttest NI all all all
Reynolds ITU/OR NI 0.05% chlorhex stat NI NI all NI all
Shivnan NI NI peroxide, PI,antibio oint Chi all 75/103 lab diff NI NI
Taylor NI NI alcoh, PI, PIO Wilcoxson NI insert removal NI NI
T/Aurand Dr aseptic NI Chi all all all CRI
Vazquez NI aseptic NI, PIO NI all NI NI all
Wille Anaes OR Protocol NI Maentel Haensel all NI all CRI
Wheeler NI aseptic NI NI all NI all CRI
Young ITU/OR aseptic alcoh chlorhex Chi Yates NI all CRS all

Key

NI = not identified
OR = opeerating room
PI = povidone Iodine
PIO = povidone Iodine ointment
ITU = intensive care unit
S/glove = sterile gloves
alcoh= alcohol
antibio= antibiotic
chlorhex = chlorhexiedine
stat NI = statistical not identified


Studies included in this review

1. Andersen, P., Herlevsen, P., Schaumburg, H., 1986. A comparative study of Opsite and Nobecutan gauze dressings for central venous line care. J. of Hospital Infection 7:161-168.

2. Brandt, B., DePalma, J., et al. 1996. Comparison of central venous catheter dressings inbone marrow transplant recipients. ONF 23. no.5:829-36.

3. Conly, J., Grieves, K., et al. 1989. A prospective, randomized study comparing transparent and dry gauze dressings for central venous catheters. The Journal of Infectious Diseases 159, no.2:310-319.

4. Engervall, P., Ringertz, S., et al. 1995. Change of central venous catheter dressing twice a week is superior to once a week in patients with haematological malignancies 29:275-286.

5. Freiberger, D., Bryant, J., et al. 1992. The effects of different central venous line dressing changes on bacterial growth in a pediatric oncology population. Journal of Pediatric Oncology Nursing 9(10:3-7.

6. Lawson, M., Kavanagh, T., et al. 1986. Comparison of transparent dressing to paper tape dressing over central venous catheter sites. NITA Vol 9:40-43.

7. Maki, D., Ringer, M,. et al. 1993. Prospective, randomized trial of povidone-iodine, alcohol and chlorhexidine for prevention of infection associated with central venous and arterial catheters. CINA Vol 9,no.1:10-15.

8. Moro, M., Lepri, V., et al. 1994. Risk factors for the central venous catheter related infections in surgical and intensive care units. Infection Control and Hospital Epidemiology 15, no.4:253-264.

9. Nehme, A., Trigger, J., 1984. Catheter dressings in central parenteral nutrition-A prospective, randomized comparative study. Nutritional Support Services 4(9) 42,48,50.

10. Palidar, P., Simonowitz D., et al. 1982. Use of Opsite as an occlusive dressing for total parenteral nutrition catheters. Journal of Parenteral and Enteral nutrition 6(1):150-151.

11. Powell, C. Regan, C. et al. 1982. Evaluating of Opsite catheter dressing for parenteral nutrition: A prospective, randomized study. Journal of Parenteral and Enteral nutrition 6(1): 43-47.

12. Powell,C. Traetow, M., et al. 1985. Opsite dressing study: A prospective, randomized study evaluating povidone-iodine ointment and extension set changes with 7 days Opsite dressing applied to total parenteral nutrition subclavian sites. Journal of Parenteral and Enteral nutrition 9(3): 443-446.

13. Prager, R., Silva, J. 1984. Colonization of central venous catheters. Southern Medical Journal Vol 77 no.4:458-461.

14. Reynolds, ., Tebbs, S., et al. 1997. Do dressings with increased permeability reduce the incidence of central venous catheter related sepsis? Intensive and Critical Care Nursing 13:26-29.

15. Shivnan, J., McGuire, D., et al. 1991. A comparison of transparent adherent and dry sterile gauze dressings for long term central catheters in patients undergoing bone marrow transplant. Oncology Nurses Forum 18(8):1349-1356.

16. Taylor, D., Myers, S., et al. 1996. Use of occlusive dressings on central venous catheter sites in hospitalized children. Journal of Pediatric nursing 11(1):169-174.

17. Treston-Aurand, J., Olmsted, R., et al. 1997. Impact of dressing materials on central venous catheter infection rates. Journal of Intravenous Nursing 20(4):201-206.

18. Vazquez, R., Jarrard, M. 1984. Care of the central venous catheterization site: The use of a transparent polyurethane film. Journal of Parenteral and Enteral Nutrition. 8(2):181-186.

19. Wheeler, W., Messner, R., et al. 1988. A comparison of transparent dressings and gauze dressings for single, lumen, non tunneled central, parenteral nutrition catheters. Nutritional Support Services. 8(9):27-28.

20. Wille, J., Albas, B., et al. 1993. A comparison of two transparent film-type dressings in central venous therapy. Journal of Hospital Infection 23:113-121.

21. Young, G., Alexeyeff, M., et al. 1988. Catheter sepsis during parenteral nutrition: the safety of long term opsite dressings. Journal of Parenteral and Enteral Nutrition.12(4):365-369.


Studies excluded

1. Babycos, C., Barrocas, A., et al. 1990.
Reason - Not clear that patients are inpatients, setting not identified.

2. Callahan, J. Wesorick, B. 1987.
Reason - Healthy population of volunteers, CVC not used for any purpose, CVC duration only 24 hours.

3. Dickerson, N. Horton, P. et al. 1989.
Reason - Commentary, insufficient data.

4. Haffejee, A. Moodley, J. et al. 1991.
Reason - n = 8.

5. Hoffmann, K. Weber, D. et al. 1992.
Reason - Meta-analysis.

6. Jarrard, M. Olson, C. et al. 1980.
Reason - Does not identify type of dressing.

7. Keenlyside, D. 1993.
Reason - Assesses ease of application, security of fixation, skin condition, control group dressing not identified.

8. Lam, S., Scannell, R., et al. 1994.
Reason - Not evaluating dressings

9. Levin, A. Mason, J. et al. 1991.
Reason - Includes outpatients.

10. Lucas, H. Attard-Montalto, S. 1996.
Reason - Includes outpatients.

11. Lucas, J., Berger, A., et al. 1992.
Reason - Includes umbilical artery and arterial lines.

12. Petrosino, B. Becker, H. et al. 1988.
Reason - Includes outpatients.

13. Popovsky, M. Ilstrup, D. 1986.
Reason - Peripheral IV catheters.

14. Raad, J., Davis, S., et al. 1993.
Reason - Not evaluating dressings.

15. Richet, H., Nitemberg, G., et al. 1990.
Reason - Dressing identified only as 'Regular'.

16. Schwartz-Fulton, H. Colley, R. et al. 1981.
Reason - Assessing bacterial growth under dressing, not evaluating dressing and dentified outcomes.


Unpublished studies that were not available

1. McKinley, S., Low, H., Mackenzie, A., Finfer, S., O'Connor, A., Green, S. 1997. Gauze dressings, antiseptic impregnated catheters and central venous catheter infections.

2. Nikoletti, S., Gandossi, S., Coombs, G., Wilson, R. 1997. Comparison of transparent polyurethane and hydrocolloid dressings for central venous catheters.


Key to Tables

 Study type comp = comparative
eval = evaluation
 Study allocation NI = not identified
R
= random
 Mean duration  identified in days
 Dressing type A = Alcohol
B = Betadine
C = Chlorhexidine
G = Gauze
HPT = Highly Permeable Transparent
NOB = Nobecutane
OP = Opsite
T = Transparent
Tg = Tegaderm
Tl = Telfa
 Dressing change OD = once daily
OW = once week
TW = twice week
3W = three times week
 Site Sub = Subclavian
Jug = Jugular
 Infection CRS = Catheter Related Sepsis- positive catheter tip culture, systemic signs and symptoms consistent with infection, fungemia or bacteremia, fever or bacteremia or fungemia in the absence of an exit site or tunnel infection, defervescence (clinical signs of infection prior to removal of catheter)
CRI = Catheter Related Infection - positive quantitative or semiquantitative culture of the catheter

LIST OF TABLES

Some Tables contain considerable data and may be slow to load

Table 1: Characteristics of included studies

Table 2. & Figure 1: Weighting of included studies

Table 3 : Summary of All Studies

Table 4 : Summary of transparent versus gauze dressings

Table 5 : Summary of transparent versus gauze with betadine dressings

Table 6 : Summary of gauze dressings

Table 7 : Summary of transparent dressings and transparent and other dressings

Table 8 : Summary of transparent, gauze and other combinations of dressings

Table 9 : Summary of studies with any significant results

Table 10 : Summary of studies with dressing change 2nd daily (including MWF dressings)

Table 11 : Summary of studies where dressing frequency is not identified

Table 12 : Summary of studies of transparent dressings change of Once a Week

Table 13 : Summary of studies of transparent dressings change less than OW

Table 14 : Summary of studies with gauze dressing change of OD

Table 15 : Summary of studies with gauze dressing change of 2nd daily

Table 16 : Summary of studies with gauze dressing change of OW


REFERENCES


Babycos, R., Barrocas, A., Mancuso, J., Turner-Marse T. 1990. Collodion as a safe, cost effective dressing for central venous catheters. Southern Medical Journal 84; 11:1286-1288.

Callahan, J., Wesorick, B. 1987. Bacterial growth under a transparent dressing. American Journal of Infection Control 15; 6:231-237.

Lucas, H., Attard-Montalto, S., 1996. Central line dressings: study of infection rates. Paediatric Nursing Jul 8; 6:21-23.

Petrosino, B., Becker, H., Becky, C. 1988. Infection rates incentral venous catheter dressings. ONF 15; 6:709-719.

Richet, H., Nitemberg, H., Andremont, A., et al. 1990. Prospective multicenter study of vascular catheter related complications and risk factors for positive central catheter cultures in intensive care unit patients. Journal of Clinical Microbiology. Nov 28; 11:2520-2525.

Speechley, V.1986. Intravenous therapy; peripheral/central lines. Nursing: the Journal of Clinical Practice, Education and Management Mar 3; 3:95-100.

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