- Email: [email protected]
Contamination of bags for continuous epidural infusion
Original Article
Contamination of bags for continuous epidural infusion Maurice Madeo, R N BSc (Hons) (1) Anita K Samaan, FP,.CA (2) W e n @ Allison, P,.N BSc (Hons) (2) J o h n A Wilson, FRCPath (i) Colin 1~ Martin, P.N PhD (2)
Abstract A prospective study was conducted firs@ to determine whether the use of an epidural infusion posed an infection risk, and secondly how often the epidural infusion set should be changed when used for short term postoperative pain relief. Eighty-nine patients were studied over a six-month period. The epidural catheter tips (EC) and infusion were cultured. The mean duration of the epidural infusion was 4.3 days (SD 1.65). Fifty-one males and 38 females were recruited with an average age of 70.5 years (SD 9.80); 43 patients had a single bag change and 46 had no bag change. Three times Staphylococa~s epidermidis and once Streptococcus vMdans were cultured from epidural fluid. Thirty-nine patients grew micro-organisms in EC tips, 31 common skin flora and eight unexpected organisms eg Adnetobaeter species (n = 5), MRSA (n = 1), coliform (n = 1 unspecified), Citwbacter species (n = 1). No patient developed local or systemic signs of infection related to the device and there was no relationship between the duration of the infusion and systemic infection related to the device. The results suggest that the routine changing of sets after a single bag change is unjustified. Acute Pain 1999; 2 (3): 125-128. Keywords: epidural infusion; infection risk; bag change; laminar flow cabinets Introduction T h e use o f epidural infusions as a m e t h o d o f providing postoperative pain relief following major surgery has become an established technique. 1,2 The risk of infection and the development of catheter-related abscesses or meningitis has to be investigated. 3 However, there is a lack of national and international guidelines regarding sterility risks associated with the use of epidural infusion lines. At Hull Royal Infirmary, epidural catheters are usually inserted in theatre preoperatively using a strict aseptic technique and infusions commenced either intra- or postoperatively, at the discretion of the consultant anaesthetist The epidural infusion used currently consists of a pre-prepared 400 ml bag of sodium chloride 0.9% mixed with bupivicaine to make a c o n c e n t r a t i o n o f 0.1% ( M a n o r Park Pharmaceuticals, Bristol). A member of the acute pain team adds diamorphine 15 mg under sterile conditions on the wards or in a theatre environment.
(1) Public Health Laboratory Service (PHLS), Hull Royal Infirmary, Hull, UK (2) Hull Royal Infirmary, Hull, UK
Acute Pain
Aims The purpose of this study was firstly to establish w h e t h e r the addition of drugs to the epidural infusion on the wards would lead to an increase in the infection rate. Secondly, to determine whether it is necessary to change the infusion sets every 24 hours as per hospital policy. Methods Subjects Fifty-one males (mean age 70.92, SD 8.95) and 38 females (mean age 69.87, SD 11.09) participated in the study. The subject sample were patients (n=89) admitted consecutively requiring postoperative pain relief after undergoing major surgery (eg repair of abdominal aortic aneurysm, oesophagectomy, bowel surgery).
Procedure All the epidural catheters for postoperative analgesia were inserted in the operating room just before surgery. A Portex size 16 FG epidural catheter was inserted using a strict aseptic technique. An aseptic
Volume 2 (3) September 1999
125
Bag contamination in continuous epidural infusion Madeo et al technique in this study resulted in the anaesthetist wearing a facemask, sterile gloves, gown and the use of a sterile field. The patient's skin was disinfected with chlorhexidine 0.5% in 70% alcohol solution and allowed to dry before cannulation was attempted; this procedure was repeated before removal of the catheter. The epidural insertion site was covered with a transparent impermeable dressing (Opsite; Smith and Nephew, Hull, UK) so that it could be inspected daily by the acute pain team. N o antibiotic prophylaxis was administered specifically for the epidural insertion. The analgesic infusion was administered using a dedicated pump (Abbott 5500) which was connected to the epidural catheter via a bacterial filter with a pore size of 0.2 microns (Portex Ltd, Hythe, Kent, England). When the initial infusion bag ran out, a new bag was commenced by a member of the acute pain team following strict guidelines to minimise the risk of contamination. On discontinuing the infusion, the giving set was sent to the laboratory for culture of the fluid. The distal end of the epidural catheter tip was cultured using the Maki roll technique aerobically and anaerobically on a 7% blood agar plate. The fluid from the distal end of the epidural set was capped off to maintain sterility and sent to the laboratory for culture using an enrichment broth. Positive catheter tip cultures were categorised into three groups, 1570 colony forming units (cfu), 71-200 cfu or greater than 200 cfu. The exit site was observed for local signs of inflammation and graded accordingly: • • • •
Statistical analysis The Spearman rho non-parametric correlation coefficient was used in the data analysis since the
15-70
CFU 71-200
>200
Total +ve
2
4
9
15 29.4%
1
1
3
5
13.1%
Table 1: Distribution of S.epidermidis between male~female patients
126
Results Eighty-eight epidural catheter tips (EC) and eightynine fluid samples from the infusion set were received for microbiological investigation.
Characteristics o f the study group The mean duration of epidural analgesia was 4.33 days (SD 1.65, range 1-8 days). Sixty-five patients continued to have the infusion in progress on or after day four. Forty-six patients did not require a bag change. Forty-three patients had a single bag change and two patients had two bag changes. One patient had three bag changes during the study period. Epidural fluid culture Four epidural fluid cultures were positive, three with S.epidermidis in the single bag change group and one positive with S. viridans from the group without a bag change.
Epidural tip culture The
bacteria most f r e q u e n t l y isolated was S.epidermidis, most probably skin flora, either from the patient or practitioner on removal of the device. If there was greater than 15 cfu this was accepted as colonisation rather than contamination.
Epidural site infection/inflammation
Satisfactory Slight redness Inflamed Discharge
Males n=51 Females n=38
categorisation criteria for determining positive cultures does not satisfy the criteria for a parametric statistical analysis.
There were no cases of epidural site infections/ inflammation on visual inspection at removal of the catheters indicating that the bacterial growth was probably due to colonisation of the catheter, There was no significant correlation between colonisation of the epidural catheter tips and the number of days the infusion was in progress (Spearman correlation 0.10). One of the limitations of the study was that no record was kept of the type and duration of antibiotic therapy given. The results show that 15.2% of patients from the no bag change group had epidural tips colonised with S.epidermidis, compared with 30.2% in the bag change group. An interesting finding was that EC tips from men were more likely to grow S.epidermidis than tips from women, See Table 1 for distribution details.
Volume 2 (3)September 1999
Acute Pain
Bag contamination in continuous epidural infusion Madeo et al
Organism isolated
15-70
<4 days 71-200 >200cfu
Gm negatives Coliforms (unsp) Citrobacter Acinetobacter spp
15-70
>4 days 71-200 >200 cfu 1
1
2
t
Gm positives 1 MRSA
S.aureus S.viridans Diptheroids S.epidermidis S. faecalis
2
1 3
1 3
1 1 2 11 1
2
3
Table 2: Total organisms cultured from E C tips
Colonisation of the EC tips appears to occur within the first four days of use (Table 2). This supports the finding that there is no correlation between colonisation of the epidural catheter and the duration of the infusion. Discussion
Continuous epidural infusions lasting several days are now an accepted means of delivering postoperative analgesia. It has been shown to provide excellent analgesia as well as to promote early recovery of bowel function and reduce the incidence of patients requiring postoperative ventilation. Bacterial c o n t a m i n a t i o n during epidural administration of analgesia has similar risk factors as intravenous infusions. Colonisation of epidural catheters may arise from the patient's skin at the exit site, by haematogenous spread from another focus or by intraluminal contamination from injectate/ infusate. The study showed that the majority of positive cultures from epidural catheter tips grew organisms usually found on the skin. One tip grew M R S A and on further investigation this patient was found to be heavily colonised, raising the question as to whether patients u n d e r g o i n g this p r o c e d u r e should be screened preoperatively. Five tips grew acinetobacter spp, w h i c h may possibly have been related to the surgical procedure involving the gastrointestinal tract or from environmental contamination. Four patients had a positive epidural fluid specimen, three of the cases (after more than 4 days duration of infusion) cultured staphylococci and one case grew S.viridans (less than 4 days duration of
Acute Pain
infusion). It is likely that contamination occurred during the addition of diamorphine to the pre-filled bupivacaine bag because of a failure in aseptic technique. It has been shown that epidural filters (Portex and Sterifix-Brann), used as part of an epidural infusion delivery system, function effectively for at least 60 days o f continuous use even when the injected solution is highly contaminated? In the entire study no patient developed any signs of local infection at the site of the epidural catheter insertion. This result is better than most other studies looking at the incidence of epidural catheter infection. We feel that though the risk of infection may be small, ideally all epidural infusions should be pre-prepared in the hospital pharmacy under laminar flow. Though the current study was limited in power because of a relatively small patient sample, the results concur with observations from larger investigations. Scott et aI5 studied 1,014 ward patients receiving epidural analgesia for 1 to 6 days and found no correlation between duration of analgesia and the incidence of local infections. However, de LeonCasasola et al, 6 in a study of 4,227 surgical cancer patients who received epidural infusions for postoperative analgesia for a mean duration of 6.3+2.6 days, reported a correlation between the duration of epidural catheterisation and infection in ward patients. Their 13 local infections (0.3%) all occurred after day seven. There were no cases of epidural abscesses detected in their study and interestingly they did not use antibacterial filters. The authors conclude that epidural catheters are a safe method of administering analgesia to the postoperative patient and the routine changing o f
Volume 2 (3) September 1999
127
Bag contamination in continuous epidural infusion Madeo et aI
epidural sets is not required in patients requiring short t e r m infusions. N o patients in this study developed signs o f local or systemic infection related to the device. It is recommended that the following good practice measures should be instituted w h e n managing or inserting an epidural device. •
D i s i n f e c t the patients' skin using i o d i n e or chlorhexidine based solution.
•
Insert the E C under strict aseptic conditions ideally in the operating theatre by an experienced practitioner using sterile gloves and sterile gown, a facemask and surgical drapes.
•
Use a sterile film dressing to aid observation o f the site.
•
Disinfect the area whenever a dressing is changed using an appropriate skin disinfectant.
•
Inspect the site at least daily.
•
Observe for local/systemic signs o f infection.
•
Maintain an intact system at all times - ideally u s e - p r e m i x e d bags or a laminar flow cabinet wherever possible.
•
Maintain a competent workforce in the care o f these devices by constantly reviewing practice based on current evidence.
128
References 1. R o y a l College of Surgeons and College o f Anaesthetists. Commission on the provision of surgical services. Report of the Working Party on Pain after Surgery. London: HMSO, 1990. 2. de Leon-Casasola OA, Parker B, Lema MJ, Harrison Massey J. Epidural analgesia versus intravenous patient-controlled analgesia: Differences in the post-operative course of cancer. Reg Anesth 1994, 19: 307-315. 3. King M. Spinal epidural abscess: An elusive diagnosis. South Medd 1994; 87: 288-289. 4. De Cicco M, Matovic M, Castellani GT, Basaglia G, et al. Time-dependent efficacy of bacterial filters and infection risk in l o n g - t e r m epidural catheterization. Anesthesiology 1995; 82. 765-771. 5. Scott DA, Beilby DSN, M c C l y m o n t C. Postoperative analgesia using epidural infusions of fentanyl with bupivacaine. Anesthesiology 1995; 83; 727-737. 6. de Leon-Casasola OA, Parker B, Lema MJ, Harrison Massey J. P o s t - o p e r a t i v e epidural bupivacaine-morphine therapy: Experience with 4,227 surgical cancer patients. Anesthesiology 1994 81: 368-375.
V o l u m e 2 ( 3 ) S e p t e m b e r 1999
Acute Pain
Contamination of bags for continuous epidural infusion Maurice Madeo, R N BSc (Hons) (1) Anita K Samaan, FP,.CA (2) W e n @ Allison, P,.N BSc (Hons) (2) J o h n A Wilson, FRCPath (i) Colin 1~ Martin, P.N PhD (2)
Abstract A prospective study was conducted firs@ to determine whether the use of an epidural infusion posed an infection risk, and secondly how often the epidural infusion set should be changed when used for short term postoperative pain relief. Eighty-nine patients were studied over a six-month period. The epidural catheter tips (EC) and infusion were cultured. The mean duration of the epidural infusion was 4.3 days (SD 1.65). Fifty-one males and 38 females were recruited with an average age of 70.5 years (SD 9.80); 43 patients had a single bag change and 46 had no bag change. Three times Staphylococa~s epidermidis and once Streptococcus vMdans were cultured from epidural fluid. Thirty-nine patients grew micro-organisms in EC tips, 31 common skin flora and eight unexpected organisms eg Adnetobaeter species (n = 5), MRSA (n = 1), coliform (n = 1 unspecified), Citwbacter species (n = 1). No patient developed local or systemic signs of infection related to the device and there was no relationship between the duration of the infusion and systemic infection related to the device. The results suggest that the routine changing of sets after a single bag change is unjustified. Acute Pain 1999; 2 (3): 125-128. Keywords: epidural infusion; infection risk; bag change; laminar flow cabinets Introduction T h e use o f epidural infusions as a m e t h o d o f providing postoperative pain relief following major surgery has become an established technique. 1,2 The risk of infection and the development of catheter-related abscesses or meningitis has to be investigated. 3 However, there is a lack of national and international guidelines regarding sterility risks associated with the use of epidural infusion lines. At Hull Royal Infirmary, epidural catheters are usually inserted in theatre preoperatively using a strict aseptic technique and infusions commenced either intra- or postoperatively, at the discretion of the consultant anaesthetist The epidural infusion used currently consists of a pre-prepared 400 ml bag of sodium chloride 0.9% mixed with bupivicaine to make a c o n c e n t r a t i o n o f 0.1% ( M a n o r Park Pharmaceuticals, Bristol). A member of the acute pain team adds diamorphine 15 mg under sterile conditions on the wards or in a theatre environment.
(1) Public Health Laboratory Service (PHLS), Hull Royal Infirmary, Hull, UK (2) Hull Royal Infirmary, Hull, UK
Acute Pain
Aims The purpose of this study was firstly to establish w h e t h e r the addition of drugs to the epidural infusion on the wards would lead to an increase in the infection rate. Secondly, to determine whether it is necessary to change the infusion sets every 24 hours as per hospital policy. Methods Subjects Fifty-one males (mean age 70.92, SD 8.95) and 38 females (mean age 69.87, SD 11.09) participated in the study. The subject sample were patients (n=89) admitted consecutively requiring postoperative pain relief after undergoing major surgery (eg repair of abdominal aortic aneurysm, oesophagectomy, bowel surgery).
Procedure All the epidural catheters for postoperative analgesia were inserted in the operating room just before surgery. A Portex size 16 FG epidural catheter was inserted using a strict aseptic technique. An aseptic
Volume 2 (3) September 1999
125
Bag contamination in continuous epidural infusion Madeo et al technique in this study resulted in the anaesthetist wearing a facemask, sterile gloves, gown and the use of a sterile field. The patient's skin was disinfected with chlorhexidine 0.5% in 70% alcohol solution and allowed to dry before cannulation was attempted; this procedure was repeated before removal of the catheter. The epidural insertion site was covered with a transparent impermeable dressing (Opsite; Smith and Nephew, Hull, UK) so that it could be inspected daily by the acute pain team. N o antibiotic prophylaxis was administered specifically for the epidural insertion. The analgesic infusion was administered using a dedicated pump (Abbott 5500) which was connected to the epidural catheter via a bacterial filter with a pore size of 0.2 microns (Portex Ltd, Hythe, Kent, England). When the initial infusion bag ran out, a new bag was commenced by a member of the acute pain team following strict guidelines to minimise the risk of contamination. On discontinuing the infusion, the giving set was sent to the laboratory for culture of the fluid. The distal end of the epidural catheter tip was cultured using the Maki roll technique aerobically and anaerobically on a 7% blood agar plate. The fluid from the distal end of the epidural set was capped off to maintain sterility and sent to the laboratory for culture using an enrichment broth. Positive catheter tip cultures were categorised into three groups, 1570 colony forming units (cfu), 71-200 cfu or greater than 200 cfu. The exit site was observed for local signs of inflammation and graded accordingly: • • • •
Statistical analysis The Spearman rho non-parametric correlation coefficient was used in the data analysis since the
15-70
CFU 71-200
>200
Total +ve
2
4
9
15 29.4%
1
1
3
5
13.1%
Table 1: Distribution of S.epidermidis between male~female patients
126
Results Eighty-eight epidural catheter tips (EC) and eightynine fluid samples from the infusion set were received for microbiological investigation.
Characteristics o f the study group The mean duration of epidural analgesia was 4.33 days (SD 1.65, range 1-8 days). Sixty-five patients continued to have the infusion in progress on or after day four. Forty-six patients did not require a bag change. Forty-three patients had a single bag change and two patients had two bag changes. One patient had three bag changes during the study period. Epidural fluid culture Four epidural fluid cultures were positive, three with S.epidermidis in the single bag change group and one positive with S. viridans from the group without a bag change.
Epidural tip culture The
bacteria most f r e q u e n t l y isolated was S.epidermidis, most probably skin flora, either from the patient or practitioner on removal of the device. If there was greater than 15 cfu this was accepted as colonisation rather than contamination.
Epidural site infection/inflammation
Satisfactory Slight redness Inflamed Discharge
Males n=51 Females n=38
categorisation criteria for determining positive cultures does not satisfy the criteria for a parametric statistical analysis.
There were no cases of epidural site infections/ inflammation on visual inspection at removal of the catheters indicating that the bacterial growth was probably due to colonisation of the catheter, There was no significant correlation between colonisation of the epidural catheter tips and the number of days the infusion was in progress (Spearman correlation 0.10). One of the limitations of the study was that no record was kept of the type and duration of antibiotic therapy given. The results show that 15.2% of patients from the no bag change group had epidural tips colonised with S.epidermidis, compared with 30.2% in the bag change group. An interesting finding was that EC tips from men were more likely to grow S.epidermidis than tips from women, See Table 1 for distribution details.
Volume 2 (3)September 1999
Acute Pain
Bag contamination in continuous epidural infusion Madeo et al
Organism isolated
15-70
<4 days 71-200 >200cfu
Gm negatives Coliforms (unsp) Citrobacter Acinetobacter spp
15-70
>4 days 71-200 >200 cfu 1
1
2
t
Gm positives 1 MRSA
S.aureus S.viridans Diptheroids S.epidermidis S. faecalis
2
1 3
1 3
1 1 2 11 1
2
3
Table 2: Total organisms cultured from E C tips
Colonisation of the EC tips appears to occur within the first four days of use (Table 2). This supports the finding that there is no correlation between colonisation of the epidural catheter and the duration of the infusion. Discussion
Continuous epidural infusions lasting several days are now an accepted means of delivering postoperative analgesia. It has been shown to provide excellent analgesia as well as to promote early recovery of bowel function and reduce the incidence of patients requiring postoperative ventilation. Bacterial c o n t a m i n a t i o n during epidural administration of analgesia has similar risk factors as intravenous infusions. Colonisation of epidural catheters may arise from the patient's skin at the exit site, by haematogenous spread from another focus or by intraluminal contamination from injectate/ infusate. The study showed that the majority of positive cultures from epidural catheter tips grew organisms usually found on the skin. One tip grew M R S A and on further investigation this patient was found to be heavily colonised, raising the question as to whether patients u n d e r g o i n g this p r o c e d u r e should be screened preoperatively. Five tips grew acinetobacter spp, w h i c h may possibly have been related to the surgical procedure involving the gastrointestinal tract or from environmental contamination. Four patients had a positive epidural fluid specimen, three of the cases (after more than 4 days duration of infusion) cultured staphylococci and one case grew S.viridans (less than 4 days duration of
Acute Pain
infusion). It is likely that contamination occurred during the addition of diamorphine to the pre-filled bupivacaine bag because of a failure in aseptic technique. It has been shown that epidural filters (Portex and Sterifix-Brann), used as part of an epidural infusion delivery system, function effectively for at least 60 days o f continuous use even when the injected solution is highly contaminated? In the entire study no patient developed any signs of local infection at the site of the epidural catheter insertion. This result is better than most other studies looking at the incidence of epidural catheter infection. We feel that though the risk of infection may be small, ideally all epidural infusions should be pre-prepared in the hospital pharmacy under laminar flow. Though the current study was limited in power because of a relatively small patient sample, the results concur with observations from larger investigations. Scott et aI5 studied 1,014 ward patients receiving epidural analgesia for 1 to 6 days and found no correlation between duration of analgesia and the incidence of local infections. However, de LeonCasasola et al, 6 in a study of 4,227 surgical cancer patients who received epidural infusions for postoperative analgesia for a mean duration of 6.3+2.6 days, reported a correlation between the duration of epidural catheterisation and infection in ward patients. Their 13 local infections (0.3%) all occurred after day seven. There were no cases of epidural abscesses detected in their study and interestingly they did not use antibacterial filters. The authors conclude that epidural catheters are a safe method of administering analgesia to the postoperative patient and the routine changing o f
Volume 2 (3) September 1999
127
Bag contamination in continuous epidural infusion Madeo et aI
epidural sets is not required in patients requiring short t e r m infusions. N o patients in this study developed signs o f local or systemic infection related to the device. It is recommended that the following good practice measures should be instituted w h e n managing or inserting an epidural device. •
D i s i n f e c t the patients' skin using i o d i n e or chlorhexidine based solution.
•
Insert the E C under strict aseptic conditions ideally in the operating theatre by an experienced practitioner using sterile gloves and sterile gown, a facemask and surgical drapes.
•
Use a sterile film dressing to aid observation o f the site.
•
Disinfect the area whenever a dressing is changed using an appropriate skin disinfectant.
•
Inspect the site at least daily.
•
Observe for local/systemic signs o f infection.
•
Maintain an intact system at all times - ideally u s e - p r e m i x e d bags or a laminar flow cabinet wherever possible.
•
Maintain a competent workforce in the care o f these devices by constantly reviewing practice based on current evidence.
128
References 1. R o y a l College of Surgeons and College o f Anaesthetists. Commission on the provision of surgical services. Report of the Working Party on Pain after Surgery. London: HMSO, 1990. 2. de Leon-Casasola OA, Parker B, Lema MJ, Harrison Massey J. Epidural analgesia versus intravenous patient-controlled analgesia: Differences in the post-operative course of cancer. Reg Anesth 1994, 19: 307-315. 3. King M. Spinal epidural abscess: An elusive diagnosis. South Medd 1994; 87: 288-289. 4. De Cicco M, Matovic M, Castellani GT, Basaglia G, et al. Time-dependent efficacy of bacterial filters and infection risk in l o n g - t e r m epidural catheterization. Anesthesiology 1995; 82. 765-771. 5. Scott DA, Beilby DSN, M c C l y m o n t C. Postoperative analgesia using epidural infusions of fentanyl with bupivacaine. Anesthesiology 1995; 83; 727-737. 6. de Leon-Casasola OA, Parker B, Lema MJ, Harrison Massey J. P o s t - o p e r a t i v e epidural bupivacaine-morphine therapy: Experience with 4,227 surgical cancer patients. Anesthesiology 1994 81: 368-375.
V o l u m e 2 ( 3 ) S e p t e m b e r 1999
Acute Pain