This cross-sectional study was carried out in the paediatric haematology-oncology ward of Dr. Behçet Uz Children's Hospital in Turkey from 1 August 2011 to 31 July 2017. Dr. Behçet Uz Children's Hospital is a 400-bed paediatric teaching hospital. At the time of the study, the oncology-haematology department had 28 beds and received 60 newly diagnosed haematologic and oncologic patients per year.
The study included 2 time periods: the 3-year baseline period before the initiation of CLB (1 Aug 2011 to 31 July 2014) and the 3-year period of CLB (1 Aug 2014 to 31 July 2017). The data were evaluated and recorded by three investigators, and the other investigators were blinded to the patients' information to protect patient confidentiality.
According to our infection control committee policy, ports were the preferred route for vascular access for paediatric haematology-oncology patients and were inserted before starting induction chemotherapy under sterile conditions in the operating room.
Microbiology and definitions:
In our centre, two central venous blood culture samples for aerobic and anaerobic cultures were taken from patients with fever under aseptic conditions and after disinfection of the central venous access device hub, in addition to a blood culture sample from peripheral veins. Fever was defined as a body temperature >38.5°C for at least 4 hours or a body temperature >39°C once. Neutropenia was described as a total number of granulocytes <0.5 × 109/L or a total number of leukocytes <1.0 × 109/L without differential counts available (17).
Each blood culture bottle (taken from blood or ports) was placed in the BacT/ALERT 9240 automated system (bioMérieux, Marcy l'Etoile, France) (18). The microorganisms were identified with a VITEK-2 compact system bioMérieux). Identification and antibiotic susceptibility tests of Gram-positive bacteria were performed using the automated VITEK-2 system with Gram-positive identification card ASTP592, a supplementary Etest (bio- Mérieux, Durham, NC, USA), and a disk diffusion test according to the manufacturer's instructions(19). This system was also used for the identification and antibiotic susceptibility tests of Gram-negative bacteria with Gram-negative identification cards AST-N325, AST-N326, and AST- N327(20). Yeast identification was performed using API 20°C AUX (bioMérieux)(21).
Pre-bundle and bundle periods:
The pre-bundle period included three years before the implementation of CLB. During this period, povidone-iodine at 10% was used for disinfection; three-way stopcocks were the choice of connection. In this period, flushing was performed using 5 or 10 mL of 0.9% NaCl, which was manually filled from everyday polyvinyl chloride bags.
The three-year CLB period comprised the following elements, including steps of needle insertion in the ports and management. The measures, including insertion of the needle in the ports, included strict hand hygiene, chlorhexidine skin antisepsis (>0.5% chlorhexidine in an alcohol solution), and complying with maximal barrier precautions. The maintenance steps included daily inspection of the catheter sites and cap connection, disinfection of the hub with > 0.5% chlorhexidine in alcohol solution, use of needless connectors (BD Q-Syte; BD, Sandy, UT), use of sterile gauze or transparent semi-permeable membrane and use of single-use prefilled saline syringes (BD PosiFlush SP, BD, NJ) for flushing.
Employees were informed about bundle implementations, and feedback was made on bundle adjustment rates and CLABSI rates in addition to educational programmes. The educational programme was provided weekly in the first six months and monthly by the bundle team, which included an infection-control nurse and a paediatric infectious disease specialist. Educational sessions were provided to all healthcare workers in the haematology-oncology ward regarding the bundle implementations for CLABSI prevention described above. Compliance with the bundle was observed by supervisor nurses and recorded in the checklist forms. The study period, prospective and active surveillance for CLABSI rates, and the monitoring of compliance with the bundle components were performed by the bundle team weekly.
Cost-analysis and statistics:
Demographic and clinical features with hospital costs and length of stay were retrospectively retrieved from the medical files and computerized hospital system. Direct medical care cost items were calculated with the hospital perspective using a combination of micro-costing technique (resource-based accounting method) and hospital list data. The direct medical costs mainly included charges for inpatient, laboratory, imaging, antimicrobial drugs, and other medications, plus operation costs for the removal of the ports if required. Attributable length of stay for hospital admission was considered as the span of days for the treatment of CLABSI. The investigators recorded the costs first in Turkish Lira (TL) and converted them to USD ($), using the average exchange rate between TL to USD currency between 1 August 2011 to 31 July 2017 (1TL=0.4484 $) (22). During the study, we did apply equal discounting of costs and health effects, which was supported by Weinstein and Stason's consistency thesis (23) and "time neutrality" by Lipscomb et al. (24). The investigators did track the costs and outcomes during the patients stay in the haematology-oncology department.
Descriptive analysis of the data was carried out by using the IBM SPSS Statistics 17.0 programme (IBM Corporation, Armonk, NY, USA). The numbers of CLABSI per day was calculated for each group. The rate of infections in two different populations was compared with the Poisson 95% confidence interval in each bundle group, and the relative risk reduction between groups was calculated and given as percentages. The relative risk reduction rate was also calculated to compare the risks for every two groups, with a 95% confidence interval for the incidence rate. The statistical analysis was performed using Medcalc v 11.6 (Ostend Belgium).
This study was approved by the local ethical committee and the institutional review board of Dr. Behçet Uz Children's Training and Research Hospital.