Surgical site infections following colorectal cancer surgery: a randomized prospective trial comparing common and advanced antimicrobial dressing containing ionic silver

Biffi Roberto, Fattori Luca, Bertani Emilio, Radice Davide, Rotmensz Nicole, Misitano Pasquale, Cenciarelli Sabine, Chiappa Antonio, Tadini Liliana, Mancini Marina, Pesenti Giovanni, Andreoni Bruno, Nespoli Angelo

Description

An antimicrobial dressing containing ionic silver was found effective in reducing surgical-site infection in a preliminary study of colorectal cancer elective surgery. We decided to test this finding in a randomized, double-blind trial. Methods Adults undergoing elective colorectal cancer surgery at two university-affiliated hospitals were randomly assigned to have the surgical incision dressed with Aquacel® Ag Hydrofiber dressing or a common dressing. To blind the patient and the nursing and medical staff to the nature of the dressing used, scrub nurses covered Aquacel® Ag Hydrofiber with a common wound dressing in the experimental arm, whereas a double common dressing was applied to patients of control group. The primary end-point of the study was the occurrence of any surgical-site infection within 30 days of surgery. Results A total of 112 patients (58 in the experimental arm and 54 in the control group) qualified for primary end-point analysis. The characteristics of the patient population and their surgical procedures were similar. The overall rate of surgical-site infection was lower in the experimental group (11.1% center 1, 17.5% center 2; overall 15.5%) than in controls (14.3% center 1, 24.2% center 2, overall 20.4%), but the observed difference was not statistically significant ( P = 0.451), even with respect to surgical-site infection grade 1 (superficial) versus grades 2 and 3, or grade 1 and 2 versus grade 3. Conclusions This randomized trial did not confirm a statistically significant superiority of Aquacel® Ag Hydrofiber dressing in reducing surgical-site infection after elective colorectal cancer surgery. Trial registration Clinicaltrials.gov: NCT00981110

Sujets

• Colorectal cancer
• Elective surgery
• Perioperative mortality

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 15
• Langue: English

Extrait

Biffi et al. World Journal of Surgical Oncology 2012, 10:94
http://www.wjso.com/content/10/1/94 WORLD JOURNAL OF
SURGICAL ONCOLOGY
RESEARCH Open Access
Surgical site infections following colorectal cancer
surgery: a randomized prospective trial
comparing common and advanced antimicrobial
dressing containing ionic silver
1* 2 3 4 4 1Roberto Biffi , Luca Fattori , Emilio Bertani , Davide Radice , Nicole Rotmensz , Pasquale Misitano ,
1 3 5 5 2 3Sabine Cenciarelli , Antonio Chiappa , Liliana Tadini , Marina Mancini , Giovanni Pesenti , Bruno Andreoni
2and Angelo Nespoli
Abstract
Background: An antimicrobial dressing containing ionic silver was found effective in reducing surgical-site
infection in a preliminary study of colorectal cancer elective surgery. We decided to test this finding in a
randomized, double-blind trial.
Methods: Adults undergoing elective colorectal cancer surgery at two university-affiliated hospitals were randomly
Wassigned to have the surgical incision dressed with Aquacel Ag Hydrofiber dressing or a common dressing. To
blind the patient and the nursing and medical staff to the nature of the dressing used, scrub nurses covered
WAquacel Ag Hydrofiber with a common wound dressing in the experimental arm, whereas a double common
dressing was applied to patients of control group. The primary end-point of the study was the occurrence of any
surgical-site infection within 30 days of surgery.
Results: A total of 112 patients (58 in the experimental arm and 54 in the control group) qualified for primary end-
point analysis. The characteristics of the patient population and their surgical procedures were similar. The overall
rate of surgical-site infection was lower in the experimental group (11.1% center 1, 17.5% center 2; overall 15.5%)
than in controls (14.3% center 1, 24.2% center 2, overall 20.4%), but the observed difference was not statistically
significant (P=0.451), even with respect to surgical-site infection grade 1 (superficial) versus grades 2 and 3, or
grade 1 and 2 versus grade 3.
WConclusions: This randomized trial did not confirm a statistically significant superiority of Aquacel Ag Hydrofiber
dressing in reducing surgical-site infection after elective colorectal cancer surgery.
Trial registration: Clinicaltrials.gov: NCT00981110
Keywords: Colorectal cancer, Elective surgery, Hydrofiber dressing, Ionic silver, Surgical site infection
* Correspondence: [e-mail]
1
Division of Abdomino-Pelvic and Minimally Invasive Surgery, European
Institute of Oncology, Via G. Ripamonti, Milan 435-20141, Italy
Full list of author information is available at the end of the article
© 2012 Biffi et al.; licensee BioMed Central Ltd This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.Biffi et al. World Journal of Surgical Oncology 2012, 10:94 Page 2 of 9
http://www.wjso.com/content/10/1/94
Background showed a reduction of this rate to 4% by substituting the
W
Surgical-site infection (SSI) occurs in 300,000 to 500,000 Aquacel Ag Hydrofiber dressing for the common dres-
patients who undergo surgery in the US each year. For sur- sing [10]. We decided to test this preliminary finding in a
gical patients, SSI are the most common hospital-acquired prospective, randomized, double-blind trial against a com-
infection. In clean-contaminated and contaminated surgery, mon dressing as control, having the main objective to
W
such as elective major colorectal surgery, there has been compare the efficacy of Aquacel Ag Hydrofiber dressing
wide discrepancy in the reported incidence of incisional with that of a common postoperative one for preventing
SSI, ranging from 3% to 30% [1,2], reflecting differences in SSIsincolorectal cancer elective surgery.
diagnostic criteria and follow-up applied. SSI is associated
with significant attributable morbidity and mortality, pro- Methods
longed hospital length of stay,andahighcosttothepatient Study design
and the institution. Several studies have suggested a doub- We conducted this prospective, randomized trial between
ling of the mortality rate, with an annual cost of $1.8 billion June 2008 and September 2010 at two university-affiliated
to the US health care system and £1 billion to the National hospitals in Italy (IEO, European Institute of Oncology,
Health Service in England [3,4]. Because the patient’sskin Milano and University of Milano-Bicocca at San Gerardo
is a major source of pathogens, it is conceivable that Hospital, Monza). The institutional review board and
improving skin antisepsis would decrease SSIs; a large ran- Ethics Committee at each hospital approved the study
domized trial has shown that preoperative cleansing of the protocol, andwritteninformedconsentwasobtained from
patient’s skin with chlorhexidine-alcohol is superior to all patients before enrollment. The trial was initially regis-
cleansing with povidone-iodine for preventing surgical-site tered at Central Registry of Randomized Clinical Trials of
infection after clean-contaminated surgery, including colo- the Italian Health Ministry, and then received registration
rectal procedures [5]. no. NCT00981110 byclinicaltrials.gov.
Ionic silver (Ag+), which is the oxidized active state of
silver, has received renewed interest and research for use Patients
as a prophylactic antimicrobial agent in wound dressings Patients aged 18 to 75 years who were undergoing colo-
due to its broad spectrum antibacterial range, including rectal cancer elective surgery by laparotomic approach
aerobic, anaerobic, Gram-negative and Gram-positive were eligible for enrollment. Exclusion criteria were a
W
bacteria, as well as yeast and fungi [6-8]. Aquacel Ag history of allergy to dressing components, evidence of
Hydrofiber dressing (ConvaTec, Princeton, NJ, USA) is a active infection at or adjacent to the operative site, coa-
moisture retention dressing that consists of soft non- gulopathy (defined as platelet count less than 50,000
woven sodium carboxymethylcellulose fibers combined cells/μL or a prothrombin time more than 18 seconds),
with 1.2% ionic silver, which is distributed throughout the intestinal obstruction, active bowel bleeding, life expect-
W
dressingmaterial. The conceptof Aquacel Ag Hydrofiber ancy less than 6 months, inability to give written
dressing is to retain the hydrofiber’sphysicalproperties informed consent or a program of minimally invasive
with the additional benefits of ionic silver, which is slowly surgery (laparoscopy or robot- assisted).
releasedintothewound,creatinga moistantimicrobialen-
vironment. Multiple clinical studies have been performed Interventions
to assess its effectiveness for the treatment of a variety of Enrolled patients were randomly assigned to have the
wounds, managed in acute and chronic settings. Neverthe- surgical incision dressed with Aquacel Ag Hydrofiber
less, a recent Cochrane systematic review failed to find an dressing (ConvaTec) in the experimental arm, or a
advantage for silver-containing wound dressings after ana- common dressing (Mepore, Molnlycke Health Care,
lyzing 26 randomized controlled trials that compared Gothenburg, Sweden) in the control arm. To help match
silver-containing wound dressings and topical agents with the two groups and address potential inter-hospital differ-
silver-containing and non-silver-containing comparators ences, randomization was stratified by hospital with the
on uninfected wounds. The authors of the review con- use of computer-generated randomization numbers
cluded that there is insufficient evidence to establish without blocking. In order to maintain the double-blind
whether silver-containing dressings or topical agents pro- characteristic of this trial, some actions were taken. First,
mote wound healing or prevent wound infection [9]. No the generator of the assignment was a data manager, who
published randomized studies have previously examined was separated from the executor; second, dressings were
the effect of silver-containing wound dressing on the inci- applied by the scrub nurses in the operating theatre at the
dence of SSI. The average baseline rate of SSI after colo- end of each procedure. The Aquacel Ag Hydrofiber
rectal cancer elective surgery at the European Institute of dressing was covered by a common wound dressing in the
Oncology was 23% with common postoperative dressing; a experimental arm, whereas a double common dressing
pilot prospective non-randomized study of 100 patients was applied to patients of the control group to blind theBiffi et al. World Journal of Surgical Oncology 2012, 10:94 Page 3 of 9
http://www.wjso.com/content/10/1/94
patient, the nursing and the medical staff and the inde- Oncology in 2007 [10]. Therefore, we planned to enroll
pendent data collector as to the nature of the dressing 56 patients in each study group for the study to have
used. All patients received a preoperative scrub and then 80% power to detect a 19% difference in the rates of SSI
painting with an aqueous solution of 10% povidone- between the two groups, using a two-sided Fisher’s exact
iodine; all patients had mechanical bowel preparation and test at a two-tailed significance level of P≤0.05. The sig-
antibiotic prophylaxis in agreement with predefined nificance of differences