Validity of a catheter exit site clinical assessment scale for the early detection of exit site infections in patients on haemodialysis with a central venous catheter: protocol for a multicentre validation study in Spain (EXITA Study)

INTRODUCTION: Haemodialysis patients with central venous catheter (HD-CVC) are at increased risk of exit site infections (ESIs) and catheter-related bloodstream infections, causing an increase of hospitalisation, morbidity and mortality rates. The main aim of the EXITA Study is to develop and validate an instrument for the early detection of HD-CVC ESIs. METHODS AND ANALYSIS: EXITA is a multicentre prospective cohort study to validate the proposed instrument with a sample of 457 HD-CVCs: 92 in the ESI group and 365 in the non-ESI group. Sample size was calculated using Epidat V.4.2 software, with 95% and 90% expected sensitivity and specificity, respectively, an ESI incidence around 20% and 5%–10% precision range. During each haemodialysis session, the absence or presence of each item will be assessed by nurses. If any item is present, a microbiological study of pericatheter skin smears and/or exit site exudate will be carried out. HD-CVC ESI will be diagnosed when the pericatheter skin smears and/or exit site exudate culture are positive (≥15 CFU/mL by semiquantitative Maki’s technique or ≥1000 CFU/mL by Cleri’s technique). To validate the scale, a logistic regression analysis will be performed: the β coefficients of each of the signs/symptoms of the scale to be validated will be estimated. We will use logit function and calculate ESI probability=e(logit ESI)/1+e(logit ESI). ETHICS AND DISSEMINATION: The study has been approved by the Research Ethics Committee with Medical Products of Cantabria (approval code 2019.146). We will obtain informed consent from all participants before data collection. We will publish the study results in a peer-reviewed scientific journal.