BJA Advance Access originally published online on October 30, 2006
British Journal of Anaesthesia 2007 98(1):131-135; doi:10.1093/bja/ael288
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Efficacy of spray disinfection with a 2-propanol and benzalkonium chloride containing solution before epidural catheter insertion—a prospective, randomized, clinical trial
1 Department of Anaesthesiology and Intensive Care, University of Pécs Hungary
2 Anaesthesiology Residency Program, Ministry of Health Hungary
3 Department of Microbiology, University of Pécs, Medical Center Hungary
*Corresponding author: Department of Anaesthetics, Monklands Hospital, Lanarkshire NHS Trust, Monkscourt Avenue, Airdrie ML6 0JS, UK. E-mail: drdebrecenig{at}hotmail.com
Accepted for publication September 16, 2006.
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Abstract |
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Background. Skin disinfection before neuroaxial blockade procedures is usually obtained with sterile swabs impregnated in disinfectant. Spray disinfection is also an option which is frequently used in minor invasive procedures. The purpose of our study was to compare the efficacy of conventional swab disinfection with spray disinfection prior to epidural catheterization.
Methods. Seventy patients who requested epidural analgesia were randomly selected. The first group (n=35) received disinfection with swabs (SW) containing 2-propanol and benzalkonium chloride. The other 35 patients received spray (SP) disinfection with the same solution. Three microbiological cultures were obtained: one culture prior to skin disinfection, a second immediately after disinfection and a third from the tip of the epidural catheter upon removal.
Results. One patient in the SW group had a positive skin culture immediately after the disinfection with a very low number of colony forming units. The other skin culture specimens were all sterile in both groups. The colonization rate of catheters was not statistically different between the groups at removal.
Conclusion. In this study, spray disinfection was equally efficacious compared with the conventional skin disinfectant technique. Our results support the routine use of this simple and cheap alternative method of skin disinfection before epidural anaesthesia.
Keywords: anaesthetic techniques, epidural; skin, disinfection, spray
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Introduction |
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Since the development of the rules of asepsis in the late 19th century, skin disinfection is obligatory before all interventions which penetrate the intact skin. The increasing use of epidural anaesthesia highlights the importance of catheter placement under aseptic circumstances. Although serious infections like bacterial meningitis and epidural abscess are rare following epidural techniques, these complications do occur and can have devastating consequences. Methods for skin disinfection vary1 and in most of the textbooks there are dogmatic regulations without evidence based recommendations. Recently published reviews2 and guidelines3 rely heavily on data extrapolated from studies on central venous catheterization. The most common practice for epidural catheter insertion is disinfecting the puncture site with sterile swabs soaked in disinfectants. Another conventional disinfection technique is spray disinfection. There is very little evidence about the superiority of either method at present.4–6 The aim of this prospective, randomized study was to compare the efficacy of skin disinfection prior to epidural catheter insertion using either swabs or spray disinfection.
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Methods |
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This study was approved by the Regional Research Ethics Committee and the Infection Control Service of the University of Pécs, Medical and Health Sciences Centre, Pécs, Hungary. Written informed consent was obtained from all patients. Seventy patients with American Society of Anesthesiologists physical status II–III who underwent various operations (Table 1) were enrolled and randomly assigned via an envelope system to undergo skin decontamination prior to epidural catheter insertion. Patients were excluded if they were under 18 yr old, had fever, diabetes, received antibiotics before the operation, were receiving steroid therapy, were immunocompromised, had HIV or pre-existing skin infection at the planned puncture site and/or had iodine allergy. All epidural catheter insertions were carried out before the initiation of general anaesthesia.
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The disinfectant used consisted of 2-propanol 63 g, benzalkonium chloride 0.025 g, water and dye in 100 g solution (Cutasept G®, Bode Chemie, Hamburg, Germany). In the SW (swab) group (n=35), the conventional technique was used for skin preparation. After hygienic hand washing wearing cap, face mask and sterile gloves an approximately 20 cm area in diameter around the planned puncture site was disinfected using sterile forceps and sterile swabs soaked in disinfectant. We repeated this procedure three times and then waited for 3 min as recommended by the manufacturer. After skin disinfection, the site was covered with a sterile sheet. Lidocaine, 80–100 mg was used to locally anaesthetize the puncture site. Following this, the epidural catheter was inserted with the standard loss of resistance technique at the lumbar or thoracic level. A sterile adhesive semi-permeable polyurethane dressing (Tegaderm® 3M, USA) was placed over the area surrounding the epidural insertion site. A bacterial filter was attached to the epidural catheter. During surgery 0.2 ml kg–1 boluses of ropivacaine 0.2% were given via the epidural catheter. After the operation patients received bupivacaine 0.125% solution continuously for pain management using syringe pumps via the same filter. In each case the patient's age, weight, height, sex, epidural site (thoracic, lumbar) and the time needed to insert the epidural catheter, hours of keeping the catheter in place, type of single shot prophylactic antibiotics, type of operation, and the signs of local irritation during catheter removal were recorded. Local irritation around the epidural catheter insertion site was documented at the time of removal. Four signs of irritation: redness, swelling, leakage and local pain were scored as present (=1) or not (=0). An insertion site without irritation was scored as 0, maximal irritation scored 4 points. During the observation period and at catheter removal the syndrome of possible epidural infection (two major symptoms: back pain and neurological deterioration and the two minor symptoms: elevated white blood cell count and fever) was noted. We did not note fever or increased white blood cell count per se if one of the major symptoms such as back pain or neurological signs were missing.
In the SP (spray) group (n=35) skin was disinfected with the same disinfectant as mentioned above using a multi-dose pressurized plastic container from which the disinfectant was sprayed on an approximately 20 cm area in diameter surrounding the puncture site three times from about 20 cm and waited 3 min as recommended by the manufacturer. Covering, local anaesthesia, insertion technique, fixing and the local anaesthetic agents were identical as in the SW group.
Three microbiological cultures were obtained from each subject: For skin cultures Envirocheck® Rodac Blister for Total Colony Count (Merck, USA) medium was used. The agar has a convex surface in it easing the obtaining of skin culture. The square lines on its transparent case help with the counting of the colony forming units of bacteria. Using sterile gloves and holding the sterile case of the medium, the convex surface of the agar was pushed onto the skin for 3 s. The first sample was obtained from the area adjacent to the planned puncture site just prior to skin disinfection to determine baseline skin flora, the second was obtained from the same area immediately after the 3 min drying time following disinfection of the skin to determine initial efficacy of the disinfectant. The plates were taken to Microbiology within an hour. Colonies were enumerated and identified by standard methods at genus level. The third sample was the distal tip of the epidural catheter itself. To reduce the risk of tip contamination by skin during removal, the area surrounding the insertion site of the catheter was disinfected by aqueous povidone-iodine solution just before removal. Once the povidone-iodine had dried, the catheters were removed using sterile gloves and a 2–3 cm distal part of the catheter was cut and placed in a sterile container using sterile scissors. All these specimens were similarly taken to Microbiology within an hour. The catheter tips were rolled four times on the surface of blood agar plates and these plates were incubated at 37°C for 48 h. Colonies were enumerated and identified by standard methods at genus level.
The anaesthesiologist obtaining the skin samples could not be blinded to the method used because the shape of the area after using SW or SP, were noticeably different.
In each case, the anaesthesiologist who obtained the epidural specimens and microbiologist handling the culture samples were blinded to the disinfection method used.
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Statistics |
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As we did not have data on colonization rate in our institution, sample sizes were based on previously published results.7 According to previous data the smallest difference between the two groups in the epidural catheter colonization rate which we did not want to be overlooked was around 30%. For the study to have 80% power at a significance level of 0.05, the estimated sample size was 30–35 patients per group. Data were presented as mean and SD. For statistical analysis we used Student's t-test for parametric data and
2-test for non parametric data. All analyses were performed with the Statistical Package for the Social Sciences (SPSS version 11.5 for Windows, Chicago, IL, 2002). |
Results |
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Out of the seventy patients enrolled, three from each group had to be excluded due to accidental removal of the epidural catheter by ward nurses. The SW and SP groups were similar with respect to height, weight, male–female ratio and age. There were no significant differences in thoracic versus lumbar epidural proportions, time of successful catheter placement, time of holding the catheter, rate of irritation at the puncture site at the time of removal (Table 2). All the patients received third generation cephalosporins as a single shot for antibiotic prophylaxis with metronidazole added for abdominal interventions. No patients received long term antibiotic treatment.
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In both groups cultures from normal, non-disinfected skin showed a normal bacterial skin flora. The most common isolates were on each patient's skin, coagulase negative Staphylococci. Other species isolated included Corynebacteria, Micrococci, Bacillus species, and
haemolytic Streptococci. The samples collected 3 min after skin disinfection and after 48 h of incubation were sterile except for one specimen in the SW group with very low CFU 1 of coagulase negative Staphylococcus and 1 of Bacillus species.
Six tips in the SW group and 2 tips in the SP group of the epidural catheters were colonized, this difference was not statistically significant (2-test, P=0.257). No catheters showed multiple colonization. The colonizing bacteria specimens were similar to normal skin flora (Table 3). None of the patients had any signs of epidural infection at the time of catheter removal.
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Discussion |
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Effective skin disinfection is thought to be an adequate measure for prevention of infection as a consequence of procedures that disrupt the skin barrier. Various kinds of skin disinfection have been used and their efficacy has been tested for various medical procedures.4–13 The most commonly used solutions are povidone–iodine, polyalcoholic preparations and chlorhexidine solutions or their mixtures.4–10 For interventions such as central venous catheterization, epidural and spinal puncture most textbooks, reviews and guidelines suggest disinfecting the skin with swabs three or four times. This method is not evidence based regarding epidural catheterization. At the same time for minor procedures (peripheral venous cannulation, minor skin operations) spray disinfection with multiple-use pressurized containers can be used. We could not find any evidence in the literature suggesting the superiority of swab over spray disinfection. Although, the efficacy of different solutions have been reported in many articles,4 9 12 only a few studies have investigated different methods with the same solution.4 5
We have chosen an alcohol based disinfectant solution since many studies revealed that alcohol based disinfectants are more powerful against microorganisms than aqueous povidone–iodine. In addition, alcohol based solutions have lower rate of allergy and fast drying.14 Birnbach and colleagues13 found that 40% of the insides of multiple-use povidone–iodine bottles were contaminated. In contrast, Robins and colleagues4 demonstrated in their study that multiple-use chlorhexidine in alcohol solution's bottles were not contaminated. There are no available data on contamination of 2-propanol and benzalkonium chloride containing multidose containers therefore we chose this solution for disinfection. However, we did not take microbiological samples from the empty vials. Robins and colleagues4 in their study compared the effect of chlorhexidine in alcohol spray from a multidose vial with an aqueous single dose chlorhexidine solution from a sachet, on skin preparation before obstetric epidural anaesthesia. They found that spraying technique was as effective as scrubbing the skin and was significantly cheaper. In their study they did not examine the epidural catheters at removal and the average duration of catheterization was about only 2.2 h while in our study this period was more than 80 h and our patient pool was based on abdominal and thoracic surgery.
Birnbach and colleagues7 and Sato and colleagues10 in their studies found that skin disinfection on the back was not capable of decreasing the number of bacteria below the level of detection. In our study there was only one patient out of 64 with detectable bacterial growth after skin disinfection. In this patient a very low number of colony forming units were found and this patient's epidural catheter tip was sterile at the time of removal. In our study the incubation period was 48 h while it was 72 h in the study of Birnbach and colleagues.7 We only touched the skin with the surface of the medium, Birnbach and colleagues5 used swabs for skin specimens while Sato and colleagues10 excised the skin to obtain bacterial specimens from the deeper layers of the skin. This may explain at least in part the difference between our findings.
We also assessed the signs of irritation at the insertion site before removal of the catheter and rated it. The scores were very low (
1 in average out of maximum 4). We did not perform skin sampling before the epidural catheter removal because we presumed that after 80 h of catheter holding we might have found normal skin flora.
In our study there was no difference between groups with regard to demographics, the time of catheter insertion procedure and the time of using the catheters. Skin flora was similar in each group. The microbiological results of tips of the catheters showed that there was a tendency of higher colonization rate in the SW group but this difference was not statistically significant. It should be noted that among the persons with colonized catheters none of them showed any sign of epidural catheter related infection.
Epidural abscess is a serious but fortunately rare complication of epidural catheterization.10 The suggested mechanism of development of the epidural abscess is sufficiently controversial. Invasion by skin bacteria through a needle track, contaminated syringes, contaminated local anaesthetics and haematogenous spread from a distant site of infection were all accused but the exact mechanism is not understood.10 In our study we examined the colonization rate of the catheters although colonization according to Simpson and colleagues8 is not a good predictor of epidural space infection and can be the result of contamination of the catheter tip upon removal.8 However, it is hard to find a perfect method to examine the connection between skin preparation and epidural infection if it exists at all. So we chose the commonly used colonization rate as an endpoint knowing that its casuality with the infection is questionable.
In conclusion, under these circumstances spray disinfection is at least effective as swab disinfection. Further studies are needed to establish any superiority.
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Acknowledgments |
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The authors would like to thank: Lajos Bogár, MD, PhD; Zsolt Molnár, MD, PhD DEAA; Subhamay Ghosh, MD, Department of Anaesthesiology and Intensive Care, University of Pécs, Hungary; and Dr Rory Mackenzie, Department of Anaesthetics, Monklands Hospital, Lanarkshire NHS Trust, Scotland for their reviewing of the manuscript and to the staff of the Department of Anaesthesiology, University of Pécs, Hungary for their help and generous support. Soli Deo Gloria.
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References |
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1 Visser L. Epidural anaesthesia. Update in Anaesthesia 2001; 11:1–4
2 Grewal S, Hocking G, Wildsmith JAW. Epidural abscesses. Br J Anaesth 2006; 96:292–302
3 Association of Anaesthetists of Great Britain and Ireland. Infect Control Anaesthesia, 23, 32, 33. Published by The Association of Anaesthetists of Great Britain and Ireland, November 2002. 2002;
4 Robins K, Wilson R, Watkins EJ, Columb MO, Lyons G. Chlorhexidine spray versus single sachets for skin preparation before regional nerve blockade for elective caesarean section: an effectiveness, time and cost study. Int J Obstet Anesth 2005; 14:189–92[CrossRef][Web of Science][Medline]
5 Moen MD, Noone MB, Kirson I. Povidone–iodine spray technique versus traditional srub-paint technique for preoperative abdominal wall preparation. Am J Obstet Gynecol 2002; 187:1434–6[CrossRef][Web of Science][Medline]
6 Gundermann KO, Christiansen B, Holler C. New methods for determining pre-operative and postoperative skin disinfection. J Hosp Infect. 1985; 6:Suppl. A, 51–7[Medline]
7 Birnbach DJ, Meadows W, Stein DJ, Murray O, Thys DM, Sordillo EM. Comparison of povidone iodine and DuraPrep an iodophor-in-isopropyl alcohol solution, for skin disinfection prior to epidural catheter insertion in parturients. Anesthesiology 2003; 98:164–9[CrossRef][Web of Science][Medline]
8 Simpson RS, Macintyre PE, Shaw D, Norton A, McCann JR, Tham EJ. Epidural catheter tip cultures: results of a 4-year audit and implications for clinical practice. Reg Anesth Pain Med 2000; 25:360–7[CrossRef][Web of Science][Medline]
9 Parienti JJ, du Cheyron D, Ramakers M, et al. Alcoholic povidone-iodine to prevent central venous catheter colonization: a randomized unit-crossover study. Crit Care Med 2004; 32:887–8[CrossRef][Web of Science][Medline]
10 Sato S, Sakuragi T, Dan K. Human skin flora as a potential source of epidural abscess. Anesthesiology 1996; 85:1276–82[CrossRef][Web of Science][Medline]
11 Yentur EA, Luleci N, Topcu I, Degerli K, Surucuoglu S. Is skin disinfection with 10 % povidone iodine sufficient to prevent epidural needle and catheter contamination? Reg Anesth Pain Med 2003; 28:389–93[CrossRef][Web of Science][Medline]
12 Kasuda H, Fukuda H, Togashi H, et al. Skin disinfection before epidural catheterization: comparative study of povidone-iodine versus chlorhexidine ethanol. Dermatology 2002; 204:Suppl. 1, 42–6
13 Birnbach DJ, Stein DJ, Murray O, Thys DM, Sordillo EM. Povidone iodine and skin disinfection before initiation of epidural anesthesia. Anesthesiology 1998; 88:668–72[CrossRef][Web of Science][Medline]
14 Maki DG, Ringer M, Alvarado CJ. Prospective randomised trial of povidone-iodine, alcohol and chlorhexidine for prevention of infection associated with central venous and arterial catheters. Lancet 1991; 338:339–43[CrossRef][Web of Science][Medline]
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