Title:

A Comparative Study of Chlorhexidine Gluconate Impregnated Dressing and Plain Occlusive Dressing on Central Venous Catheter Insertion Site in Reducing Infection Rate in Patients Undergoing Elective Major Surgeries

Introduction:

Central venous catheter placement is a common invasive procedure in perioperative management. Central venous catheter associated infection is a special concern. A number of measures have been tried to reduce infection rate. Application of occlusive dressing, antiseptic over the catheter insertion site are very important steps in reduction of infection rate. This study is planned to evaluate the effectiveness of antiseptic (Chlorhexidine Gluconate) impregnated dressings and plain occlusive dressings over central venous catheter insertion site in reducing infection rate in patients undergoing elective major surgeries.

Methods:

A prospective, randomized, single blinded, comparative study will be done in adult patients aged between 18 to 65 years, of either sex having ASA physical status 1 & 2, undergoing elective major surgical procedure (neurosurgeries for intracranial tumors, aneurysm etc.) requiring central venous catheter placement as a routine perioperative procedure. Patients with active infection or septicaemia, local site skin diseases, pregnancy, allergy to chlorhexidine and with immunocompromised state will be excluded from the surgery. After obtaining Hospital Ethical Committee approval and written informed consent, patients will be randomly assigned into two groups of 63 each (Group A & B) with the help of a computer-generated table of random numbers. After induction of anaesthesia, with proper aseptic precaution central venous catheter (15 cm, 7.5 Fr) will be inserted at either subclavian vein or internal jugular vein (right/ left sided) after cleaning of the local area with antiseptic (2% Chlorhexidine Gluconate) solution. In group A patients, antiseptic (Chlorhexidine Gluconate) impregnated dressing will be applied and in group B patients, plain occlusive dressing will be applied using aseptic technique. After surgery, patients will be extubated and shifted to high dependency unit (HDU). In the postoperative period, all patients will be receiving standard postoperative care as per institutional norm. All patients will be monitored either in HDU or ward. Dressing will be changed after 24 hours of surgery or earlier if soiled and swab sample will be sent for culture. Dressing change and sample collection will be done using aseptic techniques with similar type of dressing and after local site cleaning using similar antiseptic solution, 2% Chlorhexidine Gluconate. Paired blood samples will be taken simultaneously from peripheral vein and central venous catheter using proper aseptic technique and sent for culture after 72 hours of surgery or day of discharge whichever is earlier. Central venous catheter will be removed after taking sample for blood culture and catheter tip will be sent for culture. During these catheter-days, if any patient develops any of the symptoms and signs of infection or swab sample shows bacterial growth, the catheter will be removed after taking paired blood samples for culture from central venous catheter and peripheral vein using proper aseptic technique and catheter tip will be sent for culture. The case will be entered as ‘infected’ and dropped from the study. CRBSI will be diagnosed if isolation of the same pathogen from blood culture drawn from the central line and from a peripheral vein with the single bacterial colony count at least threefold higher in the sample from central line as compared to that obtained from peripheral vein or blood culture taken from central venous catheter turns positive at least two hours prior to simultaneous culture taken from peripheral vein.

Sample size: As per the study by Kunrong et al., removal of central venous catheter due to infection in the intervention group and control group were 24.7% ~ 25% and 14.0% respectively.^ref

Formula: The calculator uses the following formula for the sample size n:

n = (Z_α/2+Z_β)² * (p₁(1-p₁)+p₂(1-p₂)) / (p₁-p₂)²,

where Z_α/2 is the critical value of the Normal distribution at α/2 (e.g. for a confidence level of 95%, α is 0.05 and the critical value is 1.96), Z_β is the critical value of the Normal distribution at β (e.g. for a power of 80%, β is 0.2 and the critical value is 0.84) and p₁ and p₂ are the expected sample proportions of the two groups. 

Thus there will be a need of 126 patients with 80% power at 80% confidence level. The number of patients in each group will be in the ratio 1:1. Thus the number of patients in each group will be 63.

(ref: Yu K, Lu M, Meng Y, Zhao Y, Li Z. Chlorhexidine gluconate transparent dressing does not decrease central line‐associated bloodstream infection in critically ill patients: A randomized controlled trial. Int J Nurs Pract. 2019;25:e12776.)

Sampling Techniques:

The patients will be selected randomly. The random numbers will be used from Kevin Conroy: 5120 Random Numbers (<5k, 2002) [JavaScript pseudo-random number generator; Website: RandomNumber.org, 2004 ]

 Statistical analysis:

Statistical Analysis will be performed with help of Epi Info (TM) 7.2.2.2 which is a trademark of the Centers for Disease Control and Prevention (CDC).

Using this software, basic cross-tabulation and frequency distributions will be prepared. Chi-square ( ) test will be used to test the association between different study variables. Corrected  test will be used in case of any one of cell frequency will be found less than 5 in the bivariate frequency distribution. 

Test of proportion (Z-test) will be used to test the significant difference between two proportions. t-test will be used to test the significant difference between means and ‘p’ value <0.05 will be considered statistically significant.