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A randomized, prospective clinical trial to assess the potential infection risk associated with the PosiFlow® needleless connector
Journal of Hospital Infection (2003) 54, 288–293
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A randomized, prospective clinical trial to assess the potential infection risk associated with the PosiFloww needleless connector A.L. Caseya, T. Worthingtona, P.A. Lambertb, D. Quinnc, M.H. Faroquid, T.S.J. Elliotta,* a
Department of Clinical Microbiology, University Hospital Birmingham NHS Trust, The Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK b Department of Pharmaceutical and Biological Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK c Department of Cardiothoracic Surgery, University Hospital Birmingham NHS Trust, The Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK d Department of Anaesthetics and Intensive care, University Hospital Birmingham NHS Trust, The Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK Received 28 January 2003; accepted 3 March 2003
KEYWORDS Catheter; Contamination; Disinfectant; Needleless connector
Summary The microbial contamination rate of luers of central venous catheters (CVCs) with either PosiFloww needleless connectors or standard caps attached was investigated. The efficacy of 70% (v/v) isopropyl alcohol, 0.5% (w/v) chlorhexidine in gluconate 70% (v/v) isopropyl alcohol and 10% (w/v) aqueous povidone–iodine to disinfect the intravenous connections was also assessed. Seventy-seven patients undergoing cardiac surgery who required a CVC as part of their clinical management were randomly allocated either needleless connectors or standard caps. Patients were also designated to receive chlorhexidine/alcohol, isopropyl alcohol or povidone–iodine for pre-CVC insertion skin preparation and disinfection of the connections. After 72 h in situ the microbial contamination rate of 580 luers, 306 with standard caps and 274 with needleless connectors attached, was determined. The microbial contamination rate of the external compression seals of 274 needleless connectors was also assessed to compare the efficacy of the three disinfectants. The internal surfaces of 55 out of 306 (18%) luers with standard caps were contaminated with micro-organisms, whilst only 18 out of 274 (6.6%) luers with needleless connectors were contaminated ðP , 0:0001Þ: Of those needleless connectors disinfected with isopropyl alcohol, 69.2% were externally contaminated with microorganisms compared with 30.8% disinfected with chlorhexidine/alcohol ðP , 0:0001Þ and 41.6% with povidone–iodine ðP , 0:0001Þ: These results suggest that the use of needleless connectors may reduce the microbial contamination rate of CVC luers compared with the standard cap. Furthermore, disinfection of needleless connectors with either chlorhexidine/alcohol or povidone–iodine significantly reduced external microbial contamination. Both these strategies may reduce the risk of catheter-related infections acquired via the intraluminal route. Q 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved.
*Corresponding author. Tel.: þ 44-121-627-2366; fax: þ 44-121-414-1682. E-mail address: [email protected] 0195-6701/03/$ - see front matter Q 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved. doi:10.1016/S0195-6701(03)00130-0
Needleless connector contamination
Introduction Intravascular catheters are widely used in clinical practice, and continue to be the main cause of hospital-acquired bacteraemia.1 The estimated annual cost of bacteraemia associated with shortterm central venous catheters (CVCs) in the UK is £5 – 7 million.2 There are several routes by which micro-organisms may gain access to intravascular catheters.3 However, there is growing evidence to suggest that microbial contamination of the catheter hub and subsequent intraluminal migration is an important portal of entry.4 – 7 Indeed, in a recent study, 22% of stopcock entry ports and 31% of arterial line hubs were contaminated with micro-organisms after 72 h in situ.8 Several measures for the prevention of catheterrelated bloodstream infection acquired via intraluminal spread have been assessed, including needleless connectors.5,6 Needleless connectors have been primarily introduced into clinical practice to reduce the rate of needlestick injuries to heathcare workers.9 However, these devices may also facilitate aseptic technique and reduce the time spent manipulating intravascular connections thereby minimizing the risk of intraluminal contamination.10 Clinical trials that have evaluated the potential infection risk associated with needleless connectors have generated conflicting results.9 – 15 Several studies have demonstrated that needleless connectors do not increase the risk of infection acquired via intravenous catheters when an appropriate disinfection regime is employed.11 – 13 Conversely, bloodstream infections have been associated with needleless connectors in trials conducted in the surgical and home healthcare settings, however deviations from manufacturers guidelines and training deficits were observed.14,15 At present there has also been limited research to evaluate the most appropriate disinfectant for cleaning intravenous connections. In a recent study, the efficacy of 1% (w/v) aqueous chlorhexidine, 1% (w/v) chlorhexidine in 70% (v/v) ethanol, 97% (v/v) ethanol and normal saline was assessed in the decontamination of vascular catheter hubs. It was demonstrated that ethanol-based disinfectants were most effective in reducing microbial load.5 The PosiFloww needleless connector (Becton Dickinson, Utah, USA; Figure 1) is a one-piece bidirectional device, which uses standard luer-lock connections. The device incorporates a silicone compression seal that opens the fluid path when a male luer is introduced and automatically seals on withdrawal. The closed system eliminates the need
289
to remove and replace luer caps, which may leave the fluid path open and the entry port vulnerable to microbial contamination. Furthermore, the PosiFlow has the added feature of constant positive pressure, preventing the backflow of blood up the catheter during disconnection of the male luer and thereby maintaining catheter patency. In this current study, the microbial contamination of stopcock entry ports of CVCs was assessed when either PosiFlow or standard luer caps were attached. In addition, the efficacy of 0.5% (w/v) chlorhexidine in gluconate 70% (v/v) isopropyl alcohol, 70% (v/v) isopropyl alcohol and 10% (w/v) aqueous povidone –iodine for the disinfection of intravenous connections was determined.
Methods Patients Patients admitted for cardiac surgery at the University Hospital Birmingham NHS Trust, UK, and requiring a CVC as part of their clinical management were recruited into the trial after informed consent.
Clinical Protocol Each patient was randomly allocated to receive either the PosiFlow needleless connector or standard luer caps attached to stopcock entry ports on their CVC. Furthermore, each patient was randomly allocated either: chlorhexidine gluconate 0.5% (w/v) in industrial methylated spirit BP 70% (w/w) spray (Hydrexw derma spray Adams Healthcare, Leeds, UK), isopropyl alcohol 70% (w/w) spray (Spiriclensw, Adams Healthcare, Leeds, UK) or 10% (w/v) aqueous povidone – iodine (Betadinew, Purdue Frederick, Norwalk, Connecticut, USA) for pre-CVC insertion skin preparation and disinfection of the intravenous connections. Before CVC insertion, the allocated disinfectant was used to clean the insertion site and was allowed to dry for 2 min. A quad-lumen CVC with four stopcocks attached was then inserted into the right internal jugular vein of each patient by the Seldinger technique. Immediately after CVC insertion, patients in the study group had a PosiFlow attached to all entry ports of the stopcocks whilst patients in the control group had standard luer caps attached. Disinfectants allocated for pre-CVC insertion skin preparation were also used to clean the PosiFlow or stopcock entry ports before and after each manipulation, allowing the disinfectant to dry for 2 min on
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Figure 1 Three-way taps with intravenous connections. From left to right: PosiFloww and luer caps.
each occasion. In the control group, sterile luer caps were used to close the catheter system after each manipulation. Stopcock entry ports with either luer caps or PosiFlow attached were removed after 72 h in situ and placed in a sterile container for transportation to the laboratory.
Assessment of microbial contamination of the PosiFlow external compression seal The silicone compression seal of each PosiFlow was pressed on to the surface of a blood agar plate containing 7% defibrinated horse blood (Oxoid, Basingstoke, UK) 10 times and incubated at 378C in air for 48 h.
Assessment of microbial contamination of the internal components of the PosiFlow After external sampling of the PosiFlow connectors, the silicone compression seals were disinfected with a 70% (v/v) isopropyl alcohol swab (Steretsw, Seton Prebble Ltd, Merseyside, UK) and allowed to dry for 2 min. One hundred microlitres of brain – heart infusion broth (Oxoid, Basingstoke, UK) was flushed through each device three times and 80 mL inoculated on to the surface of a blood agar plate. All plates were incubated at 378C in air for 48 h.
Determination of microbial contamination of the stopcock entry ports Entry ports of the stopcocks were sampled by inserting a sterile nasopharyngeal swab (Bibby Sterilin, Abergargaed, UK) moistened with 0.9% (w/v) saline and rotated 10 times through 3608.
Each swab was inoculated onto a blood agar plate and incubated at 378C in air for 48 h.
Statistical analysis Data obtained from test patients and controls were compared using the Mann – Whitney test and Fisher’s exact test. P-values of equal to or less than 0.05 were regarded as significant.
Results Patients Seventy-seven patients were recruited into the study (41 male, 36 female with a mean age of 63 years, range: 21 – 85). Patients were admitted for surgical procedures including coronary artery bypass grafting, mitral, aortic and pulmonary valve replacement, atrial and ventricular septal defect closure/repair and aortic arch replacement. Three-hundred and six stopcock entry ports with luer caps attached were received for microbiological analysis from 39 control patients. Two hundred and seventy-four stopcock entry ports with PosiFlow attached were examined from 38 patients. None of the patients who participated in the trial exhibited clinical or microbiological symptoms of a catheter-related infection.
Microbial contamination of the PosiFlow external compression seal One hundred and fourteen out of 274 (41.6%) PosiFlow devices were externally contaminated with micro-organisms after 72 h in situ. Of these
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PosiFlow disinfected with isopropyl alcohol, 69.2% were externally contaminated with microorganisms compared with 30.8% disinfected with chlorhexidine ðP , 0:0001Þ and 25% with povidone – iodine ðP , 0:0001Þ: There was no significant difference between rates of microbial contamination of the external compression seals after disinfection with chlorhexidine or povidone –iodine ðP ¼ 0:4Þ: The numbers of micro-organisms recovered from the external surface of the PosiFlow are shown in Table I.
tamination after disinfection with either chlorhexidine, isopropyl alcohol or povidone –iodine. After disinfection of PosiFlow with either chlorhexidine or povidone – iodine, a significantly reduced microbial contamination rate of stopcock entry ports to which they were attached was observed compared with disinfection with isopropyl alcohol (P ¼ 0:02 and P ¼ 0:03; respectively).
Microbial contamination of the PosiFlow internal components
Eighty-six percent of positive cultures yielded growth of coagulase-negative staphylococci and Micrococcus spp. Staphylococcus aureus and streptococci were recovered from 2.4% of the positive cultures. Aerobic non-spore-forming Gram-positive bacilli accounted for 6.7%. Gram-negative microorganisms including Pseudomonas spp., and Neisseria spp. were isolated from 4.8 and 1.9% of positive cultures, respectively. Candida spp. were recovered from 1.4% of positive cultures.
Twenty out of 274 (7.3%) PosiFlow were internally contaminated with micro-organisms. There was no significant difference in microbial contamination rates or numbers of micro-organisms recovered from the internal components of the PosiFlow after disinfection during clinical use with isopropyl alcohol, chlorhexidine or povidone – iodine (Table I).
Microbial contamination of stopcock entry ports The microbial contamination rate of CVC stopcock entry ports with either standard luer caps or PosiFlow attached, after decontamination with the three disinfectants is shown in Table II. Stopcock entry ports with PosiFlow needleless connectors attached had a significantly lower microbial contamination rate compared with those with standard luer caps attached (6.6 versus 18%) ðP , 0:0001Þ: There was no significant difference between the numbers of colony-forming units associated with stopcock entry ports with either PosiFlow or standard caps attached ðP ¼ 0:4Þ: Of those stopcock entry ports with luer caps attached, there was no significant difference between the rates and extent of microbial con-
Micro-organisms recovered from the intravenous connections
Discussion Needdleless connectors were originally introduced into clinical practice to reduce the number of needlestick injuries to healthcare workers and their associated costs.16 Furthermore, these devices also provide a closed intravascular catheter system preventing microbial contamination of CVC stopcock entry ports. However, the infection risk associated with needleless connectors continues to be the subject of debate despite suggestions that the closed system design aids aseptic technique and reduces the time spent manipulating intravascular connections.10 In this study, 41.6% of PosiFlow needleless connectors were contaminated with micro-organisms after 72 h in situ. The high levels of microbial contamination observed on the external compression
Table I The rate and extent of external and internal microbial contamination of the PosiFlow disinfected with 0.5% chlorhexidine/alcohol, 70% isopropyl Alcohol or 10% povidone–iodine 0.5% Chlorhexidine/alcohol
70% Isopropyl alcohol
10% Povidone–iodine
Total
Number of PosiFlow assessed
91
91
92
274
External PosiFlow surface Percent contamination rate ðNÞ Mean cfu number (range)
30.8 (28) 9 (1–98)
69.2 (63) 18 (1– 138)
25 (23) 12 (1–121)
41.6 (114) 13 (1–138)
Internal PosiFlow surface Percent contamination rate ðNÞ Mean cfu number (range)
3.3 (3) 2 (1–2)
9.9 (9) 3 (1–13)
8.7 (8) 4 (1–16)
7.3 (20) 3 (1–16)
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Table II The rate and extent of stopcock entry port microbial contamination with PosiFlow or luer caps attached and disinfected with 0.5% chlorhexidine/alcohol, 70% isopropyl alcohol or 10% povidone–iodine 0.5% Chlorhexidine/alcohol Stopcock entry ports with luer caps Total number assessed 102 Percent contamination rate ðNÞ 16.7 (17) Mean cfu number (range) 7 (1–103) Stopcock entry ports with PosiFloww Total number assessed 91 Percent contamination rate (N) 1.1 (1) Mean cfu number (range) 5 (5)
seals of the PosiFlow devices may be due to several factors including; the exposed nature of the device to the environment and patients’ skin, contamination by healthcare workers during manipulation and removal and the presence of antisepticresistant strains of micro-organisms. In addition, 7.3% of PosiFlow devices were internally contaminated with micro-organisms. This contamination may have occurred through; introduction of external surface micro-organisms during the injection process, by exposure to contaminated infusates or male luers, or by microbial seeding from the catheter/bloodstream during the aspiration process. Disinfection of the devices with chlorhexidine or povidone – iodine was associated with lower rates of microbial contamination compared with those cleaned with isopropyl alcohol. Alcohol has a rapid mechanism of action compared with chlorhexidine and iodine solutions, however, evaporation occurs quickly. 17 Chlorhexidine and povidone – iodine may have longer-lasting disinfection action as evaporation occurs less rapidly, thus providing a residual effect. A trial by Maki and colleagues18 compared the use of 10% povidone – iodine, 70% alcohol and 2% aqueous chlorhexidine for pre-CVC insertion and exit site antisepsis, and found that chlorhexidine was associated with the lowest rates of localized infection and bacteraemia. In contrast to our findings, povidone – iodine was no more efficient than alcohol in reducing the rate of infections. Indeed, there is only limited evidence in the literature to suggest that povidone – iodine has more efficient antimicrobial properties than alcohol or chlorhexidine. All three disinfectants used have a different mode of antimicrobial action.17 Therefore it may have been the combined effects of the alcohol and chlorhexidine when used in combination in this study that resulted in the lowest intravenous connection contamination rates. Indeed, the study carried out by Salzman and colleagues5 suggested that the addition of 1%
70% Isopropyl alcohol
10% Povidone– iodine
Total
102 21.6 (22) 8 (1–67)
102 15.7 (16) 70 (1–810)
306 18 (55) 28 (1–810)
91 9.9 (9) 3 (1–3)
92 8.7 (8) 7 (1– 22)
274 6.6 (18) 5 (1– 22)
chlorhexidine to 70% ethanol was superior to 70% ethanol alone in the disinfection of catheter hubs. Chlorhexidine requires extended exposure to air for its antimicrobial effects to be observed.5 The PosiFlow has a flat external surface that is easily disinfected compared with the open luer thus facilitating aseptic technique. Low external PosiFlow contamination rates may consequently reduce the potential risk of micro-organisms being transferred from the external compression seal to the entry ports of which the PosiFlow are attached. Eighteen percent of stopcock entry ports with luer caps attached were contaminated with microorganisms after 72 h in situ, which concurs with data from previous studies.8,11 However, in contrast to a previous study, which evaluated the Clavew needleless connector (ICU Medical Inc, California, USA),11 stopcock entry ports with PosiFlow attached were associated with a significantly lower contamination rate than those with luer caps. Disinfection of the entry ports with either chlorhexidine of povidone – iodine resulted in a reduced rate of microbial contamination compared with those cleaned with isopropyl alcohol. This suggests that isopropyl alcohol, which is commonly used in clinical practice, is not optimal for disinfection of intravenous connections. The cardiac surgery critical care unit of the University Hospital Birmingham NHS Trust currently uses stopcocks disinfected with isopropyl alcohol, and luer caps. In this current study, this resulted in 21.6% of stopcock entry ports being contaminated with micro-organisms. The results of this clinical trial suggest that microbial contamination of stopcock entry ports may be reduced by incorporating needleless connectors into clinical practice for use with intravenous connections. Indeed, PosiFlow needleless connectors disinfected with 0.5% chlorhexidine in 70% isopropyl alcohol before and after each manipulation reduced stopcock entry port contamination to 1.1%. These strategies may aid in reducing catheter-related bloodstream infection
Needleless connector contamination
acquired via the intraluminal route and therefore reduce costs associated with catheter-related sepsis.
Acknowledgements We thank all the healthcare workers from cardiac theatres, the cardiac surgery critical care unit and cardiac surgery wards. We also thank Becton Dickinson who provided an educational grant to support this work.
References 1. Correa L, Pittet D. Problems and solutions in hospitalacquired bacteraemia. J Hosp Infect 2000;46:89—95. 2. Moss HA, Elliott TSJ. The cost of infections related to central venous catheters designed for long term use. Br J Med Economics 1997;11:1—7. 3. Elliott TSJ, Faroqui MH. Infections and intravascular devices. Br J Hosp Med 1992;48:496—503. 4. Salzman MB, Isenberg HD, Shapiro JF, Lipsitz PJ, Rubin LG. A prospective study of the catheter hub as the portal of entry for microorganisms causing catheter-related sepsis in neonates. J Infect Dis 1993;167:487—490. 5. Salzman MB, Isenberg HD, Rubin LG. Use of disinfectants to reduce microbial contamination of hubs of vascular catheters. J Clin Microbiol 1993;31:475—479. 6. Segura M, Alvarez-Lerma F, Tellado JM, et al. A clinical trial on the prevention of catheter-related sepsis using a new hub model. Ann Surg 1996;223:363—369. 7. Salzman MB, Rubin LG. Relevance of the catheter hub as a portal for microorganisms causing catheter-related bloodstream infections. Nutrition 1997;13(Suppl.):S15—S17.
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8. Tebbs SE, Ghose A, Elliott TSJ. Microbial contamination of intravenous and arterial catheters. Intens Care Med 1996; 22:272—273. 9. Russo PL, Harrington GA, Spelman DW. Needleless intravenous systems: a review. Am J Infect Control 1999;27: 431—434. 10. Brown JD, Moss HA, Elliott TSJ. The potential for catheter microbial contamination from a needleless connector. J Hosp Infect 1997;36:181—189. 11. Seymour VM, Dhallu TS, Moss HA, Tebbs SE, Elliott TSJ. A prospective clinical study to investigate the microbial contamination of a needleless connector. J Hosp Infect 2000;45:165—168. 12. Adams KS, Zehrer CL, Thomas W. Comparison of a needleless system with conventional heparin locks. Am J Infect Control 1993;21:263—269. 13. Lucet JC, Hayon J, Bruneel F, Dumoulin JL, Joly-Guillou ML. Microbiological evaluation of central venous catheter administration hubs. Infect Control Hosp Epidemiol 2000; 21:40—42. 14. Cookson ST, Ihrig M, O’Mara EM, et al. Increased bloodstream infection rates in surgical patients associated with variation from recommended use and care following implementation of a needleless device. Infect Control Hosp Epidemiol 1998;19:23—27. 15. Kellerman S, Shay DK, Howard J, et al. Bloodstream infections in home infusion patients: the influence of race and needleless intravascular access devices. J Pediatr 1996; 129:711—717. 16. Orenstein R, Reynolds L, Karabaic M, Markowitz SM, Wong ES. Do protective devices prevent needlestick injuries among health care workers? Am J Infect Control 1995;23: 344—351. 17. Larson E. Draft guideline for use of topical antimicrobial agents. Am J Hosp Infect 1987;15:A25—A36. 18. Maki DG, Ringer M, Alvarado CJ. Prospective randomized trial of povidone—iodine, alcohol, and chlorhexidine for prevention of infection associated with central venous and arterial catheters. Lancet 1991;338:339—343.
www.elsevierhealth.com/journals/jhin
A randomized, prospective clinical trial to assess the potential infection risk associated with the PosiFloww needleless connector A.L. Caseya, T. Worthingtona, P.A. Lambertb, D. Quinnc, M.H. Faroquid, T.S.J. Elliotta,* a
Department of Clinical Microbiology, University Hospital Birmingham NHS Trust, The Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK b Department of Pharmaceutical and Biological Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK c Department of Cardiothoracic Surgery, University Hospital Birmingham NHS Trust, The Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK d Department of Anaesthetics and Intensive care, University Hospital Birmingham NHS Trust, The Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK Received 28 January 2003; accepted 3 March 2003
KEYWORDS Catheter; Contamination; Disinfectant; Needleless connector
Summary The microbial contamination rate of luers of central venous catheters (CVCs) with either PosiFloww needleless connectors or standard caps attached was investigated. The efficacy of 70% (v/v) isopropyl alcohol, 0.5% (w/v) chlorhexidine in gluconate 70% (v/v) isopropyl alcohol and 10% (w/v) aqueous povidone–iodine to disinfect the intravenous connections was also assessed. Seventy-seven patients undergoing cardiac surgery who required a CVC as part of their clinical management were randomly allocated either needleless connectors or standard caps. Patients were also designated to receive chlorhexidine/alcohol, isopropyl alcohol or povidone–iodine for pre-CVC insertion skin preparation and disinfection of the connections. After 72 h in situ the microbial contamination rate of 580 luers, 306 with standard caps and 274 with needleless connectors attached, was determined. The microbial contamination rate of the external compression seals of 274 needleless connectors was also assessed to compare the efficacy of the three disinfectants. The internal surfaces of 55 out of 306 (18%) luers with standard caps were contaminated with micro-organisms, whilst only 18 out of 274 (6.6%) luers with needleless connectors were contaminated ðP , 0:0001Þ: Of those needleless connectors disinfected with isopropyl alcohol, 69.2% were externally contaminated with microorganisms compared with 30.8% disinfected with chlorhexidine/alcohol ðP , 0:0001Þ and 41.6% with povidone–iodine ðP , 0:0001Þ: These results suggest that the use of needleless connectors may reduce the microbial contamination rate of CVC luers compared with the standard cap. Furthermore, disinfection of needleless connectors with either chlorhexidine/alcohol or povidone–iodine significantly reduced external microbial contamination. Both these strategies may reduce the risk of catheter-related infections acquired via the intraluminal route. Q 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved.
*Corresponding author. Tel.: þ 44-121-627-2366; fax: þ 44-121-414-1682. E-mail address: [email protected] 0195-6701/03/$ - see front matter Q 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved. doi:10.1016/S0195-6701(03)00130-0
Needleless connector contamination
Introduction Intravascular catheters are widely used in clinical practice, and continue to be the main cause of hospital-acquired bacteraemia.1 The estimated annual cost of bacteraemia associated with shortterm central venous catheters (CVCs) in the UK is £5 – 7 million.2 There are several routes by which micro-organisms may gain access to intravascular catheters.3 However, there is growing evidence to suggest that microbial contamination of the catheter hub and subsequent intraluminal migration is an important portal of entry.4 – 7 Indeed, in a recent study, 22% of stopcock entry ports and 31% of arterial line hubs were contaminated with micro-organisms after 72 h in situ.8 Several measures for the prevention of catheterrelated bloodstream infection acquired via intraluminal spread have been assessed, including needleless connectors.5,6 Needleless connectors have been primarily introduced into clinical practice to reduce the rate of needlestick injuries to heathcare workers.9 However, these devices may also facilitate aseptic technique and reduce the time spent manipulating intravascular connections thereby minimizing the risk of intraluminal contamination.10 Clinical trials that have evaluated the potential infection risk associated with needleless connectors have generated conflicting results.9 – 15 Several studies have demonstrated that needleless connectors do not increase the risk of infection acquired via intravenous catheters when an appropriate disinfection regime is employed.11 – 13 Conversely, bloodstream infections have been associated with needleless connectors in trials conducted in the surgical and home healthcare settings, however deviations from manufacturers guidelines and training deficits were observed.14,15 At present there has also been limited research to evaluate the most appropriate disinfectant for cleaning intravenous connections. In a recent study, the efficacy of 1% (w/v) aqueous chlorhexidine, 1% (w/v) chlorhexidine in 70% (v/v) ethanol, 97% (v/v) ethanol and normal saline was assessed in the decontamination of vascular catheter hubs. It was demonstrated that ethanol-based disinfectants were most effective in reducing microbial load.5 The PosiFloww needleless connector (Becton Dickinson, Utah, USA; Figure 1) is a one-piece bidirectional device, which uses standard luer-lock connections. The device incorporates a silicone compression seal that opens the fluid path when a male luer is introduced and automatically seals on withdrawal. The closed system eliminates the need
289
to remove and replace luer caps, which may leave the fluid path open and the entry port vulnerable to microbial contamination. Furthermore, the PosiFlow has the added feature of constant positive pressure, preventing the backflow of blood up the catheter during disconnection of the male luer and thereby maintaining catheter patency. In this current study, the microbial contamination of stopcock entry ports of CVCs was assessed when either PosiFlow or standard luer caps were attached. In addition, the efficacy of 0.5% (w/v) chlorhexidine in gluconate 70% (v/v) isopropyl alcohol, 70% (v/v) isopropyl alcohol and 10% (w/v) aqueous povidone –iodine for the disinfection of intravenous connections was determined.
Methods Patients Patients admitted for cardiac surgery at the University Hospital Birmingham NHS Trust, UK, and requiring a CVC as part of their clinical management were recruited into the trial after informed consent.
Clinical Protocol Each patient was randomly allocated to receive either the PosiFlow needleless connector or standard luer caps attached to stopcock entry ports on their CVC. Furthermore, each patient was randomly allocated either: chlorhexidine gluconate 0.5% (w/v) in industrial methylated spirit BP 70% (w/w) spray (Hydrexw derma spray Adams Healthcare, Leeds, UK), isopropyl alcohol 70% (w/w) spray (Spiriclensw, Adams Healthcare, Leeds, UK) or 10% (w/v) aqueous povidone – iodine (Betadinew, Purdue Frederick, Norwalk, Connecticut, USA) for pre-CVC insertion skin preparation and disinfection of the intravenous connections. Before CVC insertion, the allocated disinfectant was used to clean the insertion site and was allowed to dry for 2 min. A quad-lumen CVC with four stopcocks attached was then inserted into the right internal jugular vein of each patient by the Seldinger technique. Immediately after CVC insertion, patients in the study group had a PosiFlow attached to all entry ports of the stopcocks whilst patients in the control group had standard luer caps attached. Disinfectants allocated for pre-CVC insertion skin preparation were also used to clean the PosiFlow or stopcock entry ports before and after each manipulation, allowing the disinfectant to dry for 2 min on
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Figure 1 Three-way taps with intravenous connections. From left to right: PosiFloww and luer caps.
each occasion. In the control group, sterile luer caps were used to close the catheter system after each manipulation. Stopcock entry ports with either luer caps or PosiFlow attached were removed after 72 h in situ and placed in a sterile container for transportation to the laboratory.
Assessment of microbial contamination of the PosiFlow external compression seal The silicone compression seal of each PosiFlow was pressed on to the surface of a blood agar plate containing 7% defibrinated horse blood (Oxoid, Basingstoke, UK) 10 times and incubated at 378C in air for 48 h.
Assessment of microbial contamination of the internal components of the PosiFlow After external sampling of the PosiFlow connectors, the silicone compression seals were disinfected with a 70% (v/v) isopropyl alcohol swab (Steretsw, Seton Prebble Ltd, Merseyside, UK) and allowed to dry for 2 min. One hundred microlitres of brain – heart infusion broth (Oxoid, Basingstoke, UK) was flushed through each device three times and 80 mL inoculated on to the surface of a blood agar plate. All plates were incubated at 378C in air for 48 h.
Determination of microbial contamination of the stopcock entry ports Entry ports of the stopcocks were sampled by inserting a sterile nasopharyngeal swab (Bibby Sterilin, Abergargaed, UK) moistened with 0.9% (w/v) saline and rotated 10 times through 3608.
Each swab was inoculated onto a blood agar plate and incubated at 378C in air for 48 h.
Statistical analysis Data obtained from test patients and controls were compared using the Mann – Whitney test and Fisher’s exact test. P-values of equal to or less than 0.05 were regarded as significant.
Results Patients Seventy-seven patients were recruited into the study (41 male, 36 female with a mean age of 63 years, range: 21 – 85). Patients were admitted for surgical procedures including coronary artery bypass grafting, mitral, aortic and pulmonary valve replacement, atrial and ventricular septal defect closure/repair and aortic arch replacement. Three-hundred and six stopcock entry ports with luer caps attached were received for microbiological analysis from 39 control patients. Two hundred and seventy-four stopcock entry ports with PosiFlow attached were examined from 38 patients. None of the patients who participated in the trial exhibited clinical or microbiological symptoms of a catheter-related infection.
Microbial contamination of the PosiFlow external compression seal One hundred and fourteen out of 274 (41.6%) PosiFlow devices were externally contaminated with micro-organisms after 72 h in situ. Of these
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PosiFlow disinfected with isopropyl alcohol, 69.2% were externally contaminated with microorganisms compared with 30.8% disinfected with chlorhexidine ðP , 0:0001Þ and 25% with povidone – iodine ðP , 0:0001Þ: There was no significant difference between rates of microbial contamination of the external compression seals after disinfection with chlorhexidine or povidone –iodine ðP ¼ 0:4Þ: The numbers of micro-organisms recovered from the external surface of the PosiFlow are shown in Table I.
tamination after disinfection with either chlorhexidine, isopropyl alcohol or povidone –iodine. After disinfection of PosiFlow with either chlorhexidine or povidone – iodine, a significantly reduced microbial contamination rate of stopcock entry ports to which they were attached was observed compared with disinfection with isopropyl alcohol (P ¼ 0:02 and P ¼ 0:03; respectively).
Microbial contamination of the PosiFlow internal components
Eighty-six percent of positive cultures yielded growth of coagulase-negative staphylococci and Micrococcus spp. Staphylococcus aureus and streptococci were recovered from 2.4% of the positive cultures. Aerobic non-spore-forming Gram-positive bacilli accounted for 6.7%. Gram-negative microorganisms including Pseudomonas spp., and Neisseria spp. were isolated from 4.8 and 1.9% of positive cultures, respectively. Candida spp. were recovered from 1.4% of positive cultures.
Twenty out of 274 (7.3%) PosiFlow were internally contaminated with micro-organisms. There was no significant difference in microbial contamination rates or numbers of micro-organisms recovered from the internal components of the PosiFlow after disinfection during clinical use with isopropyl alcohol, chlorhexidine or povidone – iodine (Table I).
Microbial contamination of stopcock entry ports The microbial contamination rate of CVC stopcock entry ports with either standard luer caps or PosiFlow attached, after decontamination with the three disinfectants is shown in Table II. Stopcock entry ports with PosiFlow needleless connectors attached had a significantly lower microbial contamination rate compared with those with standard luer caps attached (6.6 versus 18%) ðP , 0:0001Þ: There was no significant difference between the numbers of colony-forming units associated with stopcock entry ports with either PosiFlow or standard caps attached ðP ¼ 0:4Þ: Of those stopcock entry ports with luer caps attached, there was no significant difference between the rates and extent of microbial con-
Micro-organisms recovered from the intravenous connections
Discussion Needdleless connectors were originally introduced into clinical practice to reduce the number of needlestick injuries to healthcare workers and their associated costs.16 Furthermore, these devices also provide a closed intravascular catheter system preventing microbial contamination of CVC stopcock entry ports. However, the infection risk associated with needleless connectors continues to be the subject of debate despite suggestions that the closed system design aids aseptic technique and reduces the time spent manipulating intravascular connections.10 In this study, 41.6% of PosiFlow needleless connectors were contaminated with micro-organisms after 72 h in situ. The high levels of microbial contamination observed on the external compression
Table I The rate and extent of external and internal microbial contamination of the PosiFlow disinfected with 0.5% chlorhexidine/alcohol, 70% isopropyl Alcohol or 10% povidone–iodine 0.5% Chlorhexidine/alcohol
70% Isopropyl alcohol
10% Povidone–iodine
Total
Number of PosiFlow assessed
91
91
92
274
External PosiFlow surface Percent contamination rate ðNÞ Mean cfu number (range)
30.8 (28) 9 (1–98)
69.2 (63) 18 (1– 138)
25 (23) 12 (1–121)
41.6 (114) 13 (1–138)
Internal PosiFlow surface Percent contamination rate ðNÞ Mean cfu number (range)
3.3 (3) 2 (1–2)
9.9 (9) 3 (1–13)
8.7 (8) 4 (1–16)
7.3 (20) 3 (1–16)
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A.L. Casey et al.
Table II The rate and extent of stopcock entry port microbial contamination with PosiFlow or luer caps attached and disinfected with 0.5% chlorhexidine/alcohol, 70% isopropyl alcohol or 10% povidone–iodine 0.5% Chlorhexidine/alcohol Stopcock entry ports with luer caps Total number assessed 102 Percent contamination rate ðNÞ 16.7 (17) Mean cfu number (range) 7 (1–103) Stopcock entry ports with PosiFloww Total number assessed 91 Percent contamination rate (N) 1.1 (1) Mean cfu number (range) 5 (5)
seals of the PosiFlow devices may be due to several factors including; the exposed nature of the device to the environment and patients’ skin, contamination by healthcare workers during manipulation and removal and the presence of antisepticresistant strains of micro-organisms. In addition, 7.3% of PosiFlow devices were internally contaminated with micro-organisms. This contamination may have occurred through; introduction of external surface micro-organisms during the injection process, by exposure to contaminated infusates or male luers, or by microbial seeding from the catheter/bloodstream during the aspiration process. Disinfection of the devices with chlorhexidine or povidone – iodine was associated with lower rates of microbial contamination compared with those cleaned with isopropyl alcohol. Alcohol has a rapid mechanism of action compared with chlorhexidine and iodine solutions, however, evaporation occurs quickly. 17 Chlorhexidine and povidone – iodine may have longer-lasting disinfection action as evaporation occurs less rapidly, thus providing a residual effect. A trial by Maki and colleagues18 compared the use of 10% povidone – iodine, 70% alcohol and 2% aqueous chlorhexidine for pre-CVC insertion and exit site antisepsis, and found that chlorhexidine was associated with the lowest rates of localized infection and bacteraemia. In contrast to our findings, povidone – iodine was no more efficient than alcohol in reducing the rate of infections. Indeed, there is only limited evidence in the literature to suggest that povidone – iodine has more efficient antimicrobial properties than alcohol or chlorhexidine. All three disinfectants used have a different mode of antimicrobial action.17 Therefore it may have been the combined effects of the alcohol and chlorhexidine when used in combination in this study that resulted in the lowest intravenous connection contamination rates. Indeed, the study carried out by Salzman and colleagues5 suggested that the addition of 1%
70% Isopropyl alcohol
10% Povidone– iodine
Total
102 21.6 (22) 8 (1–67)
102 15.7 (16) 70 (1–810)
306 18 (55) 28 (1–810)
91 9.9 (9) 3 (1–3)
92 8.7 (8) 7 (1– 22)
274 6.6 (18) 5 (1– 22)
chlorhexidine to 70% ethanol was superior to 70% ethanol alone in the disinfection of catheter hubs. Chlorhexidine requires extended exposure to air for its antimicrobial effects to be observed.5 The PosiFlow has a flat external surface that is easily disinfected compared with the open luer thus facilitating aseptic technique. Low external PosiFlow contamination rates may consequently reduce the potential risk of micro-organisms being transferred from the external compression seal to the entry ports of which the PosiFlow are attached. Eighteen percent of stopcock entry ports with luer caps attached were contaminated with microorganisms after 72 h in situ, which concurs with data from previous studies.8,11 However, in contrast to a previous study, which evaluated the Clavew needleless connector (ICU Medical Inc, California, USA),11 stopcock entry ports with PosiFlow attached were associated with a significantly lower contamination rate than those with luer caps. Disinfection of the entry ports with either chlorhexidine of povidone – iodine resulted in a reduced rate of microbial contamination compared with those cleaned with isopropyl alcohol. This suggests that isopropyl alcohol, which is commonly used in clinical practice, is not optimal for disinfection of intravenous connections. The cardiac surgery critical care unit of the University Hospital Birmingham NHS Trust currently uses stopcocks disinfected with isopropyl alcohol, and luer caps. In this current study, this resulted in 21.6% of stopcock entry ports being contaminated with micro-organisms. The results of this clinical trial suggest that microbial contamination of stopcock entry ports may be reduced by incorporating needleless connectors into clinical practice for use with intravenous connections. Indeed, PosiFlow needleless connectors disinfected with 0.5% chlorhexidine in 70% isopropyl alcohol before and after each manipulation reduced stopcock entry port contamination to 1.1%. These strategies may aid in reducing catheter-related bloodstream infection
Needleless connector contamination
acquired via the intraluminal route and therefore reduce costs associated with catheter-related sepsis.
Acknowledgements We thank all the healthcare workers from cardiac theatres, the cardiac surgery critical care unit and cardiac surgery wards. We also thank Becton Dickinson who provided an educational grant to support this work.
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