Innovative dressing and securement of tunneled central venous access devices in pediatrics: a pilot randomized controlled trial

Children undergoing treatment for oncological and hematological conditions are some of the most vulnerable patients in hospital settings. Functioning, complication-free vascular access for anti-cancer therapies, antibiotics, nutrition and blood sampling is vital to their treatment and survival. Tunneled, cuffed central venous access devices (CVADs), commonly referred to by their trade names, Hickman® or Broviac® catheters, are inserted for children requiring multiple or frequent infusions of irritant or vesicant fluids over prolonged periods of time (≥3 months) [1]. The pediatric population requiring this type of central device is primarily receiving treatment for oncological (e.g. neuroblastoma), hematological (e.g. aplastic anemia) or gastroenterological (e.g. intestinal failure) conditions [2, 3].

Tunneled, cuffed CVADs incorporate a short Dacron cuff designed to inhibit ascending migration of organisms from the skin, and to stimulate tissue growth around the cuff to anchor the device [4]. However Dacron cuff adhesion takes up to four weeks [4, 5], longer when the patient is compromised, placing the CVAD at significant risk of dislodgement or infection prior to that time. While historically considered a ‘safe’ device, a recent meta-analysis [6] demonstrated 29% of pediatric tunneled cuffed CVADs failed prior to completion of therapy (0.86 per 1,000 catheter days), with 20% developing a CVAD-associated bloodstream infection (BSI) (1.13 per 1,000 catheter days), and 7% dislodging completely (0.24 per 1,000 catheter days).

A key strategy to decrease the risk of CVAD-associated complication is to ensure the insertion wound is adequately covered to prevent infection, and the device secured to prevent internal and external motion [7]. Traditionally CVAD insertion sites were covered with sterile gauze and tape, with polyurethane dressings becoming prominent practice in the 1990s [8]. The devices are also internally and/or externally sutured, with these sutures removed, or dissolving, at around 7–10 days. The current failure and complication rates associated with CVADs suggest that habitual practices of their dressing and securement are inadequate.

A recent Cochrane systematic review [9] highlighted the dearth of literature to support clinical decision making in the area of CVAD securement, considering the range of available products. Previous randomized controlled trials (RCTs) of securement and dressing products for tunneled, cuffed CVAD are dated [10, 11] and have limited their study population to adults [10, 12‐14]. No previous RCTs have focused on children or examined the issue of CVAD security. The physiology and pathophysiology of children requiring these devices necessitates a specialist focus [15].

Newer CVAD securement and dressing products are available, which may be superior to traditional methods. Integrated securement-dressings (ISDs) incorporate a strengthened securement system across the entire polyurethane dressing, over and underneath the CVAD body [7]. ISDs also surround the polyurethane with an absorbent layer, to maintain dressing integrity when exposed to insertion site exudate. Suture-less securement devices (SSD) comprise of soft footplates with fastening clasps of hard plastic or soft Velcro to reduce movement and catheter rotation [16]. Tissue adhesive (TA), a medical grade ‘superglue’ (cyanoacrylate), can provide strength and hemostatic properties [17], which may be beneficial for patients experiencing large amounts of post-insertion exudate due to underlying pathologies. However, it is not known whether these new products are more effective at reducing pediatric CVAD failure and complication, in comparison to traditional care. In order to reduce CVAD associated complications in the pediatric population, RCTs of CVAD securement products are necessary to provide true estimates of relative effectiveness and inform practice [18]. Prior to undertaking large efficacy trials, external pilot studies are necessary to examine issues of research feasibility including intervention acceptability, compliance and recruitment [18].

The study recruited for 21 months, commencing at the Royal Children’s Hospital, Brisbane in April 2014 until pausing recruitment in October 2014 due to the merger of two pediatric hospitals, and relocation to a new hospital. Recruitment recommenced at the Lady Cilento Children’s Hospital, Brisbane in March 2015, completing recruitment in May 2016 when sample size was achieved. The CONSORT flow chart [40] is displayed in Fig. 2, demonstrating enrolment, allocation, follow-up and analysis of the study participants. Ninety-six patients were screened for recruitment, with 68 eligible, and 48 children participating in the pilot study.

This is the world’s first randomized controlled trial evaluating the effectiveness of tunneled CVAD dressing and securement in pediatrics. The trial included innovative securement strategies that had never been tested on this device type, or within this population. This pilot trial evaluated the feasibility of a large efficacy trial, using pre-determined feasibility criteria, a registered and published trial protocol, and rigorous methods.

As per our a priori definition of feasibility, a large efficacy trial of tunneled, cuffed CVAD securement and dressing in pediatrics, using these intervention arms, is feasible. Study processes were successful, with targets for eligibility, recruitment, retention, attrition, protocol adherence and missing data achieved. The proportion of failure (6%) and complication (6%) have provided point estimates for future interventional studies; and for a 5% absolute reduction in CVAD failure or complication is to be reached in future efficacy studies (p = 0.05; 80% power [39]), 211 participants would be needed for each intervention group. The slow recruitment rate in the pilot trial (48 participants over 21 months), means that conducting the efficacy RCT in a single site would be difficult, and a multisite trial, involving other tertiary pediatric hospitals, would be necessary.

However, of the three CVAD failures within the trial, one was not directly associated with the securement device. Within the ISD group, a CVAD spontaneously internally displaced into a non-central position. This suggests the definition of failure would need amending, to exclude this form of failure, in future trials. Overall, it is too soon to assess if one CVAD dressing and securement option is superior. At this early stage of trialing, all products appear generally safe and feasible for future testing. Our feasibility outcomes demonstrated that high-quality research examining CVAD securement in this population is achievable; however the best product for future research is yet to be established.

The most common cause of CVAD-associated complication within the pilot study was partial dislodgement (2/48; 4%), occurring in two of the intervention arms (ISD, SSD). The rates of complication and failure evident in our study were lower than the recent meta-analysis of observational studies, which found an average CVAD failure proportion of 25% [6], but still demonstrate the problems associated with CVAD management in pediatrics. Despite higher complications rates, parent satisfaction was highest for the ISD arm, with TA and SSD also performing better than standard care.

Within this study both TA and ISD showed potential to increase the time between CVAD insertion and first dressing change, and their true effectiveness and cost-effectiveness should be further investigated. Minimization of dressing changes during the immediate post-insertion period is an important concern for this population. Pediatric patients are frequently non-compliant, and extremely stressed by CVAD dressing changes. Each dressing disruption also potentially places the patient at increased risk for CVAD-associated infection [41] and accidental dislodgement.

Each of the experimental arms was more expensive than standard care, when only basic product purchase costs were considered per application. Additional costs related to the time of skilled clinicians applying and removing the products were not considered, nor the cost of treating complications and failure. These short-term, immediate costs should be weighed against the potential sequelae, if reductions in dressing change frequency, CVAD-associated complications and catheter failure are prevented. Recent case-control studies demonstrated that pediatric CVAD-associated BSIs cost healthcare systems around $55,646 (2011 USD) and 19 additional days admitted to hospital [42], with even higher costs ($69,332; 2011 USD; 21.2 additional days in hospital) for the hematology and oncology pediatric population [43]. Delays to treatment and the insertion of replacement CVADs due to other causes of CVAD failure and complication are also expensive to healthcare systems, and have a significant impact on the morbidity and mortality of pediatric patients. Investment in more expensive CVAD securement devices is likely to be cost-effective if significant improvements in CVAD complication and failure rates can be attained, and future research needs to investigate this.

The recent Cochrane review [9] found moderate quality evidence that chlorhexidine gluconate-impregnated dressing products significantly reduced catheter-related BSI per 1, 000 patient days, and catheter tip colonization, compared with conventional polyurethane dressings. However the majority of these studies were within the adult, critical care population and transferability of these results outside of this population has not been established. Researchers should build on previous work [12, 14] to further examine the role of chlorhexidine gluconate-impregnated dressing products in the oncology and pediatric domain.

CVAD-associated skin injuries were a substantial issue within our study, with site complications identified in 9% of participants, with two additional participants (4%) withdrawing from the study due to skin irritation. This suggests CVAD-associated skin injuries should be included as a primary, rather than a secondary endpoint in future studies. Pediatric CVAD sites are at risk for significant damage due to the combination of skin impairment related to the patient’s age and morbidity, and additional irritation of the CVAD site during maintenance procedures [44]. Local site infection, moisture-related injuries, contact dermatitis and medical adhesive-related injuries (MARSI) related to CVAD sites are frequently reported in the literature [9, 44‐48]; however overall prevalence rates have not been published. Identifying patients at risk for skin complication and instituting preventative strategies will further improve clinical outcomes for this vulnerable population.

This pilot study has several limitations. The sample size is small, and the results should not be used to guide clinical practice, however it was never designed to do so. The study was only carried out in two sites in Queensland and its generalizability outside of this population is unknown. Participants, family members and the research staff were not blinded to the intervention allocation, due to the visibility of the securement products. It is highly unlikely that they would intentionally cause CVAD complications because of any preference for any of the treatment arms. The study outcomes of CABSI, catheter-related BSI, and venous thrombosis were assessed by blinded infectious diseases and radiological personnel. The validity and reliability of the study has been ensured through following a prospectively registered study protocol, independent randomization, dedicated ReN, and allocation concealment until study entry.

High-quality research involving children with tunneled, cuffed CVADs is feasible, and CVAD securement can play an important role in the prevention of CVAD-associated complications [9, 49, 50]. Careful consideration should be given by interdisciplinary clinicians when choosing CVAD securement, to ensure it is the most appropriate device for the individual needs of their patient. Further research is necessary to examine the effectiveness of novel securement and dressing products for CVADs in pediatrics.