Journal
of Hospital
Infection
(1991)
19, 257-262
Infective complications associated with the Quinton ‘Permcath’ for long-term vascular access in haemodialysis M. S. Dryden*,
A. Samson?, H. A. Ludlam**, I. Phillips*
the use of central
A. J. Wing?
and
*Departments of Microbiology and TRenal Medicine, UMDS and St Thomas’ Hospital, London SE1 7EH and **Department of Microbiology, St Bartholomew’s Hospital, London EClA 7BE Accepted for publication 20 September 1991 Summary:
The major complication of central venous catheterization for immediate access for haemodialysis is infection. The Quinton Permcath is a tunnelled, double lumen, flexible silastic catheter with a Dacron cuff, and is claimed to be associated with a low rate of infection. In a two-year study we have monitored all complications including catheter-associated infection related to this device in haemodialysis patients while following a simple aseptic programme for the care of the catheter exit wound. Thirty four Permcaths were inserted in 30 patients for a mean duration of 6.2 months (SD f 5.7; range 2 days to 23 months). Catheter use amounted to a total of 197 months. Of twenty-seven catheter wound infections, 6 (22%) were caused by Staphylococcus aureus, and 15 (56%) by coagulase-negative staphylococci or corynebacteria. These occurred in 19 patients, giving an exit site infection rate of one episode per 7.4 catheter months. Catheter-associated septicaemia occurred in three patients (two S. aureus, one S. epidermidis), at a rate of one episode per 66 months. It was possible to correlate three episodes of infection with breakdown in aseptic care. This study confirms the low rate of infection associated with the use of the Permcath, and we conclude that the design of the device and aseptic care of the catheter and its wound contribute to this. Keywords:
Infection;
haemodialysis;
central
vascular
access.
Introduction The provision of vascular access (central or femoral vascular cannulation, or arteriovenous shunts) for immediate haemodialysis in renal failure remains a problem which is fraught with complications including trauma, infection, Although central venous cannulation thrombosis and haemorrhage.‘-2 permits dialysis, while sparing peripheral vessels, the catheter may be required to be in place for a long period of time, and the risk of infection increases with the length of time the catheter is in situ.3,4 Correspondence 01954701/92/120257+06
to: Dr M. S. Dryden. 8 1991 The Hospital
$03.0010
257
Infection
Society
258
M. S. Dryden
et al.
Recent reports describing the use of a double-lumen, tunnelled silastic catheter bearing a dacron cuff (‘Permcath’, Quinton Instrument Company, Seattle) have suggested that this device has a lower rate of complications than other temporary catheters. ‘3~ However, there have been few reported details of methods of catheter maintenance, and of the infections associated with this device. We have used the Permcath in our Renal Unit in patients where central haemodialysis access has been necessary for a period of greater than 6 weeks. For two years we have recorded all complications, including infection, while maintaining a simple antiseptic programme for the care of catheters and their wounds.
Methods
Patients Over a 2-year period we studied all patients with chronic end-stage renal failure in whom Permcaths were inserted. These were patients in whom central venous access was required for haemodialysis for a minimum of 6 weeks. The patients were awaiting definitive renal replacement therapy: maturation of peripheral arterio-venous fistulae, insertion of a Tenckhoff tube for continuous ambulatory peritoneal dialysis, or renal transplantation. In a few cases all alternative dialysis methods were exhausted, and central venous cannulation was the final means of access. Central venous catheters The Quinton Permcath is a 28 cm silicone rubber, double-lumen catheter with dual extension ports, closed by sealing caps. There is a Dacron felt cuff 19 cm from the proximal tip. The catheters were inserted with full aseptic precautions under general anaesthesia by a single surgical team. They are tunnelled for c. 4 cm beneath the anterior chest wall before passing over the clavicle and entering the internal jugular vein, with the tip positioned just inside the right atrium. Prophylactic antibiotics were not used. Catheter and wound care After insertion the Permcath was held in position with a skin stitch for 10 days until the tunnelling was healed. The site was covered with an occlusive dressing (‘Mepore’, Molnlycke Ltd., Dunstable, UK). Patients presented to the Renal Unit twice or three times a week for haemodialysis. Before dialysis, the dressing was removed and the state of the entry site assessed. Attending nurses were trained in the aseptic care of the catheter and its wound. The nurses’ hands were first disinfected with 0.5% chlorhexidine in 70% isopropyl alcohol (‘Hibisol’, ICI Pharmaceuticals, UK), and the dressing removed. Sterile latex gloves were worn, the exit site cleaned with alcoholic povidone-iodine (‘Betadine’, Napp Laboratories Ltd., Cambridge, UK), and a fresh dressing applied. The nurse changed gloves and thoroughly wiped each limb of the Permcath with alcoholic
Infection
of central
vascular
catheter
259
povidone-iodine before removing and discarding the limb caps. The ports were cleaned with alcoholic povidone-iodine before connection to the dialysis machine. After dialysis the catheter was disconnected from the dialysis machine and the limbs re-capped with full aseptic precautions. The Permcaths were used for haemodialysis access only. Catheter wound assessment Patients were instructed to return to the Unit if the catheter exit site became inflamed, painful or discharged pus. In addition, at each dressing change the state of the catheter wound was assessed. The presence of erythema, discharge of pus and pain were recorded. Clinical catheter wound infection was defined as the presence of a rim of erythema of 1 cm diameter or greater surrounding the catheter, or the discharge of pus with or without pain. If clinical infection was present a swab was collected from the wound for bacteriological culture. If catheter-associated septicaemia was suspected, at least two blood cultures were collected from peripheral vessels. IVlicrobiological methods Bacteria were identified by standard further characterized by phage typing.
methods,
and staphylococci
were
Results
Patients During the 2-year study period, 34 Permcaths were inserted in 30 patients, aged between 23 and 81 (mean 48) years for haemodialysis access. All patients had chronic renal insufficiency. Four of 30 were insulin-dependent diabetics and six were being treated with corticosteroids. Central cenous catheters Permcath use in the study patients amounted to 197 patient-months in total. The mean duration was 6.2 months (SD f 5.7), with a range of 2 days to 23 months. Six catheters remained in use at the end of the study. Two catheters were removed and replaced within 2 days of insertion because of lumen obstruction due to thrombosis. Twenty-three catheters were of alternative definitive removed for the following reasons: maturation dialysis access (14), renal transplantation (3), catheter-associated septicaemia (3), accidental removal (3). In addition three patients died during the study. Their deaths were unrelated to catheter use. Additional complications which did not result in the loss of the Permcath were wound haemorrhage (l), thrombosis (2) and blockage of lumen by broken limb cap (1). Catheter wound infection Twenty-seven episodes of clinical
catheter
wound
infection
occurred
in 19
260
M. S. Dryden
et al.
patients. The catheter wound infection rate was one episode per 7.39 catheter-months. Infections occurred between 1 and 32 weeks (mean 9.2 weeks) after insertion of the catheter. Three of four diabetic patients and five of seven patients receiving steroid therapy acquired catheter wound infections. There was no statistical difference in the rate of wound infection between those patients with diabetes or on steroid therapy and those without (P= 0.5). Patients presented with erythema and pain in nine cases, purulent discharge and pain in eight cases, erythema and pus in ten cases. Culture of clinically infected catheter wound sites yielded a variety of organisms: Staphylococcus aureus (6), coagulase-negative staphylococci (12), Corynebacterium spp. (9), and Enterococus faecalis (1). In six episodes the culture yielded a mixed growth. In three episodes of wound infection it was possible to elicit a clear history of breakdown in the aseptic procedure. In one episode a damaged limb cap necessitated excessive handling of the catheter, and in two others the Permcaths had remained in situ but unused and untended for several weeks following renal transplantation. Appropriate antibiotic therapy was prescribed in 19 of the infections, and no catheters were removed due to unresolving infection. Bacteria were recovered from blood Catheter-associated septicaemia. cultured from three patients with suspected septicaemia, equivalent to a rate of one episode of catheter-associated septicaemia every 66 catheter-months. In all three cases, isolates from the peripheral blood were indistinguishable from isolates recovered from the catheter wounds (two S. aureus and one S. epidermidis). Septicaemia occurred after use of the Permcath for 28 weeks in both cases of S. aureus infection, and after 3 weeks in the third case. All cases responded to parenteral antibiotic therapy, and the Permcaths were removed electively. Discussion
In patients with chronic renal failure, central venous cannulation permits immediate haemodialysis while they are awaiting more permanent methods of renal replacement therapy, for example haemodialysis via peripheral arteriovenous fistulae, continuous ambulatory peritoneal dialysis or renal Conventional subclavian cannulation for haemodialysis transplantation. infection is one access has a lifespan of 2-3 weeks,6 and catheter-associated of the main reasons for failure of this technique with the incidence of septicaemia reported to range between one episode every 4.25 months to one every 22 catheter months.6 Since arteriovenous fistulae frequently take 8-12 weeks to mature, repeated subclavian catheter insertions may be necessary with the attendant complications of pneumoand haemothorax and subclavian vein thrombosis6 A number of studies have reported a low incidence of infection following
Infection
of central
vascular
catheter
261
central cannulation with the Quinton Permcath.5a6s9 The success of this device has been attributed to subcutaneous tunnelling and the presumed protective effect of a Dacron cuff. However, there has been little published detail of clinical presentation of Permcath-associated infection or the microbiological findings and little data on catheter care. In this study, we have observed the complications associated with Permcath use while applying simple aseptic care to the catheter and its wound. This was associated with an infection rate of one episode of exit site sepsis per 7.3 catheter months and one episode of septicaemia per 66 catheter months, confirming the low rate of infection associated with the use of the Permcath. It is difficult to compare this data with that of other studies, none of which give rates of infection. Schwab et nl. report 23 exit site infections and one bacteraemia following 80 Permcath insertions, with a mean catheter life of 8 weeks.6 In another study with a mean catheter life closer to the one in this study, three episodes of septicaemia occurred in a group of 57 patients with Permcaths.’ We conclude that the use of the Permcath in central venous cannulaton for haemodialysis has a low rate of associated infection. It is not possible to evaluate which factors make the greatest contribution to this. While it may in part be related to the design of the device, subcutaneous tunnelling and a Dacron cuff, the method of insertion and the aseptic care of the catheter wound is of undoubted importance in the prevention of infection, and for this to be achieved a trained and dedicated staff is a prerequisite.‘” Prophylactic antibiotics at the time of Permcath insertion would not further reduce infection, as all the catheter wound infections in this study occurred a week or more after insertion, and a recent double blind placebo-controlled trial of prophylactic vancomycin for central venous catheter insertion failed to reduce catheter-associated sepsis.” Aseptic catheter wound care in this study was basic. Stringent aseptic nursing care has been shown to reduce catheter-associated sepsis in a controlled study in studies of such rigorous patients receiving parenteral nutrition. lo Controlled care applied to central venous catheters for haemodialysis are indicated. References 1, Pourchez ‘I’, Moriniere P, Fournier A, Pietri J. Use of Permcath (Quinton) catheter in uraemic patients in whom the creation of conventional vascular access for haemodialysis is difficult. Nephron 1989; 53: 297-302. 2. Rello J, Campistol JR/I, Almirall J, Revert L. Vascular access for haemodialysis. Lancet 1989; 1: 379. 3, Elliott TS J. Intravascular device infections. J Med Microbial 1988; 27: 161-l 67. 4. Eykyn SJ. Infection and intravascular catheters. J Antimicrob Chemother 1984; 14: 203-208. 5. Bour ES, Weaver AS, Yang HC, Gifford RR. Experience with the double lumen Silastic catheter for haemoaccess. Sul;g Gynecol Obstet 1990; 171: 33-39. 6. Schwab SJ, Buller GL, McCann RL, Bollinger RR, Stickel DL. Prospective evaluation of a Dacron cuffed hemodialysis catheter for prolonged use. AmJ Kidney Dis 1988; 11: 166-169.
262
M. S. Dryden
et al.
7. Dahlberg PJ, Yutuc WR, Newcomver K. Subclavian hemodialysis catheter infections. Am J Kidney Dis 1986; 5: 421427. 8. Maki DG, Goldman DA, Rhame FS. Infection control in intravenous therapy. Ann Int Med 1973; 79: 867-887. 9. Chatelard P, Trolliet P, Gilly F, et al. Emergency vascular access in patients with renal failure. J Chir 1990; 127: 13-16. 10. Keohane PP, Jones BJM, Attrill H, et al. Effect of catheter tunnelling and a nutrition nurse on catheter sepsis during parenteral nutrition. A controlled trial. Lancet 1983; 2: 1388-1390. 11. Ranson MR, Oppenheim BA, Jackson A, Kamthan AG, Scarffe JH. Double-blind placebo controlled study of vancomycin prophylaxis for central venous catheter insertion in cancer patients. J Hasp Infect 1990; 15: 95-102.
of Hospital
Infection
(1991)
19, 257-262
Infective complications associated with the Quinton ‘Permcath’ for long-term vascular access in haemodialysis M. S. Dryden*,
A. Samson?, H. A. Ludlam**, I. Phillips*
the use of central
A. J. Wing?
and
*Departments of Microbiology and TRenal Medicine, UMDS and St Thomas’ Hospital, London SE1 7EH and **Department of Microbiology, St Bartholomew’s Hospital, London EClA 7BE Accepted for publication 20 September 1991 Summary:
The major complication of central venous catheterization for immediate access for haemodialysis is infection. The Quinton Permcath is a tunnelled, double lumen, flexible silastic catheter with a Dacron cuff, and is claimed to be associated with a low rate of infection. In a two-year study we have monitored all complications including catheter-associated infection related to this device in haemodialysis patients while following a simple aseptic programme for the care of the catheter exit wound. Thirty four Permcaths were inserted in 30 patients for a mean duration of 6.2 months (SD f 5.7; range 2 days to 23 months). Catheter use amounted to a total of 197 months. Of twenty-seven catheter wound infections, 6 (22%) were caused by Staphylococcus aureus, and 15 (56%) by coagulase-negative staphylococci or corynebacteria. These occurred in 19 patients, giving an exit site infection rate of one episode per 7.4 catheter months. Catheter-associated septicaemia occurred in three patients (two S. aureus, one S. epidermidis), at a rate of one episode per 66 months. It was possible to correlate three episodes of infection with breakdown in aseptic care. This study confirms the low rate of infection associated with the use of the Permcath, and we conclude that the design of the device and aseptic care of the catheter and its wound contribute to this. Keywords:
Infection;
haemodialysis;
central
vascular
access.
Introduction The provision of vascular access (central or femoral vascular cannulation, or arteriovenous shunts) for immediate haemodialysis in renal failure remains a problem which is fraught with complications including trauma, infection, Although central venous cannulation thrombosis and haemorrhage.‘-2 permits dialysis, while sparing peripheral vessels, the catheter may be required to be in place for a long period of time, and the risk of infection increases with the length of time the catheter is in situ.3,4 Correspondence 01954701/92/120257+06
to: Dr M. S. Dryden. 8 1991 The Hospital
$03.0010
257
Infection
Society
258
M. S. Dryden
et al.
Recent reports describing the use of a double-lumen, tunnelled silastic catheter bearing a dacron cuff (‘Permcath’, Quinton Instrument Company, Seattle) have suggested that this device has a lower rate of complications than other temporary catheters. ‘3~ However, there have been few reported details of methods of catheter maintenance, and of the infections associated with this device. We have used the Permcath in our Renal Unit in patients where central haemodialysis access has been necessary for a period of greater than 6 weeks. For two years we have recorded all complications, including infection, while maintaining a simple antiseptic programme for the care of catheters and their wounds.
Methods
Patients Over a 2-year period we studied all patients with chronic end-stage renal failure in whom Permcaths were inserted. These were patients in whom central venous access was required for haemodialysis for a minimum of 6 weeks. The patients were awaiting definitive renal replacement therapy: maturation of peripheral arterio-venous fistulae, insertion of a Tenckhoff tube for continuous ambulatory peritoneal dialysis, or renal transplantation. In a few cases all alternative dialysis methods were exhausted, and central venous cannulation was the final means of access. Central venous catheters The Quinton Permcath is a 28 cm silicone rubber, double-lumen catheter with dual extension ports, closed by sealing caps. There is a Dacron felt cuff 19 cm from the proximal tip. The catheters were inserted with full aseptic precautions under general anaesthesia by a single surgical team. They are tunnelled for c. 4 cm beneath the anterior chest wall before passing over the clavicle and entering the internal jugular vein, with the tip positioned just inside the right atrium. Prophylactic antibiotics were not used. Catheter and wound care After insertion the Permcath was held in position with a skin stitch for 10 days until the tunnelling was healed. The site was covered with an occlusive dressing (‘Mepore’, Molnlycke Ltd., Dunstable, UK). Patients presented to the Renal Unit twice or three times a week for haemodialysis. Before dialysis, the dressing was removed and the state of the entry site assessed. Attending nurses were trained in the aseptic care of the catheter and its wound. The nurses’ hands were first disinfected with 0.5% chlorhexidine in 70% isopropyl alcohol (‘Hibisol’, ICI Pharmaceuticals, UK), and the dressing removed. Sterile latex gloves were worn, the exit site cleaned with alcoholic povidone-iodine (‘Betadine’, Napp Laboratories Ltd., Cambridge, UK), and a fresh dressing applied. The nurse changed gloves and thoroughly wiped each limb of the Permcath with alcoholic
Infection
of central
vascular
catheter
259
povidone-iodine before removing and discarding the limb caps. The ports were cleaned with alcoholic povidone-iodine before connection to the dialysis machine. After dialysis the catheter was disconnected from the dialysis machine and the limbs re-capped with full aseptic precautions. The Permcaths were used for haemodialysis access only. Catheter wound assessment Patients were instructed to return to the Unit if the catheter exit site became inflamed, painful or discharged pus. In addition, at each dressing change the state of the catheter wound was assessed. The presence of erythema, discharge of pus and pain were recorded. Clinical catheter wound infection was defined as the presence of a rim of erythema of 1 cm diameter or greater surrounding the catheter, or the discharge of pus with or without pain. If clinical infection was present a swab was collected from the wound for bacteriological culture. If catheter-associated septicaemia was suspected, at least two blood cultures were collected from peripheral vessels. IVlicrobiological methods Bacteria were identified by standard further characterized by phage typing.
methods,
and staphylococci
were
Results
Patients During the 2-year study period, 34 Permcaths were inserted in 30 patients, aged between 23 and 81 (mean 48) years for haemodialysis access. All patients had chronic renal insufficiency. Four of 30 were insulin-dependent diabetics and six were being treated with corticosteroids. Central cenous catheters Permcath use in the study patients amounted to 197 patient-months in total. The mean duration was 6.2 months (SD f 5.7), with a range of 2 days to 23 months. Six catheters remained in use at the end of the study. Two catheters were removed and replaced within 2 days of insertion because of lumen obstruction due to thrombosis. Twenty-three catheters were of alternative definitive removed for the following reasons: maturation dialysis access (14), renal transplantation (3), catheter-associated septicaemia (3), accidental removal (3). In addition three patients died during the study. Their deaths were unrelated to catheter use. Additional complications which did not result in the loss of the Permcath were wound haemorrhage (l), thrombosis (2) and blockage of lumen by broken limb cap (1). Catheter wound infection Twenty-seven episodes of clinical
catheter
wound
infection
occurred
in 19
260
M. S. Dryden
et al.
patients. The catheter wound infection rate was one episode per 7.39 catheter-months. Infections occurred between 1 and 32 weeks (mean 9.2 weeks) after insertion of the catheter. Three of four diabetic patients and five of seven patients receiving steroid therapy acquired catheter wound infections. There was no statistical difference in the rate of wound infection between those patients with diabetes or on steroid therapy and those without (P= 0.5). Patients presented with erythema and pain in nine cases, purulent discharge and pain in eight cases, erythema and pus in ten cases. Culture of clinically infected catheter wound sites yielded a variety of organisms: Staphylococcus aureus (6), coagulase-negative staphylococci (12), Corynebacterium spp. (9), and Enterococus faecalis (1). In six episodes the culture yielded a mixed growth. In three episodes of wound infection it was possible to elicit a clear history of breakdown in the aseptic procedure. In one episode a damaged limb cap necessitated excessive handling of the catheter, and in two others the Permcaths had remained in situ but unused and untended for several weeks following renal transplantation. Appropriate antibiotic therapy was prescribed in 19 of the infections, and no catheters were removed due to unresolving infection. Bacteria were recovered from blood Catheter-associated septicaemia. cultured from three patients with suspected septicaemia, equivalent to a rate of one episode of catheter-associated septicaemia every 66 catheter-months. In all three cases, isolates from the peripheral blood were indistinguishable from isolates recovered from the catheter wounds (two S. aureus and one S. epidermidis). Septicaemia occurred after use of the Permcath for 28 weeks in both cases of S. aureus infection, and after 3 weeks in the third case. All cases responded to parenteral antibiotic therapy, and the Permcaths were removed electively. Discussion
In patients with chronic renal failure, central venous cannulation permits immediate haemodialysis while they are awaiting more permanent methods of renal replacement therapy, for example haemodialysis via peripheral arteriovenous fistulae, continuous ambulatory peritoneal dialysis or renal Conventional subclavian cannulation for haemodialysis transplantation. infection is one access has a lifespan of 2-3 weeks,6 and catheter-associated of the main reasons for failure of this technique with the incidence of septicaemia reported to range between one episode every 4.25 months to one every 22 catheter months.6 Since arteriovenous fistulae frequently take 8-12 weeks to mature, repeated subclavian catheter insertions may be necessary with the attendant complications of pneumoand haemothorax and subclavian vein thrombosis6 A number of studies have reported a low incidence of infection following
Infection
of central
vascular
catheter
261
central cannulation with the Quinton Permcath.5a6s9 The success of this device has been attributed to subcutaneous tunnelling and the presumed protective effect of a Dacron cuff. However, there has been little published detail of clinical presentation of Permcath-associated infection or the microbiological findings and little data on catheter care. In this study, we have observed the complications associated with Permcath use while applying simple aseptic care to the catheter and its wound. This was associated with an infection rate of one episode of exit site sepsis per 7.3 catheter months and one episode of septicaemia per 66 catheter months, confirming the low rate of infection associated with the use of the Permcath. It is difficult to compare this data with that of other studies, none of which give rates of infection. Schwab et nl. report 23 exit site infections and one bacteraemia following 80 Permcath insertions, with a mean catheter life of 8 weeks.6 In another study with a mean catheter life closer to the one in this study, three episodes of septicaemia occurred in a group of 57 patients with Permcaths.’ We conclude that the use of the Permcath in central venous cannulaton for haemodialysis has a low rate of associated infection. It is not possible to evaluate which factors make the greatest contribution to this. While it may in part be related to the design of the device, subcutaneous tunnelling and a Dacron cuff, the method of insertion and the aseptic care of the catheter wound is of undoubted importance in the prevention of infection, and for this to be achieved a trained and dedicated staff is a prerequisite.‘” Prophylactic antibiotics at the time of Permcath insertion would not further reduce infection, as all the catheter wound infections in this study occurred a week or more after insertion, and a recent double blind placebo-controlled trial of prophylactic vancomycin for central venous catheter insertion failed to reduce catheter-associated sepsis.” Aseptic catheter wound care in this study was basic. Stringent aseptic nursing care has been shown to reduce catheter-associated sepsis in a controlled study in studies of such rigorous patients receiving parenteral nutrition. lo Controlled care applied to central venous catheters for haemodialysis are indicated. References 1, Pourchez ‘I’, Moriniere P, Fournier A, Pietri J. Use of Permcath (Quinton) catheter in uraemic patients in whom the creation of conventional vascular access for haemodialysis is difficult. Nephron 1989; 53: 297-302. 2. Rello J, Campistol JR/I, Almirall J, Revert L. Vascular access for haemodialysis. Lancet 1989; 1: 379. 3, Elliott TS J. Intravascular device infections. J Med Microbial 1988; 27: 161-l 67. 4. Eykyn SJ. Infection and intravascular catheters. J Antimicrob Chemother 1984; 14: 203-208. 5. Bour ES, Weaver AS, Yang HC, Gifford RR. Experience with the double lumen Silastic catheter for haemoaccess. Sul;g Gynecol Obstet 1990; 171: 33-39. 6. Schwab SJ, Buller GL, McCann RL, Bollinger RR, Stickel DL. Prospective evaluation of a Dacron cuffed hemodialysis catheter for prolonged use. AmJ Kidney Dis 1988; 11: 166-169.
262
M. S. Dryden
et al.
7. Dahlberg PJ, Yutuc WR, Newcomver K. Subclavian hemodialysis catheter infections. Am J Kidney Dis 1986; 5: 421427. 8. Maki DG, Goldman DA, Rhame FS. Infection control in intravenous therapy. Ann Int Med 1973; 79: 867-887. 9. Chatelard P, Trolliet P, Gilly F, et al. Emergency vascular access in patients with renal failure. J Chir 1990; 127: 13-16. 10. Keohane PP, Jones BJM, Attrill H, et al. Effect of catheter tunnelling and a nutrition nurse on catheter sepsis during parenteral nutrition. A controlled trial. Lancet 1983; 2: 1388-1390. 11. Ranson MR, Oppenheim BA, Jackson A, Kamthan AG, Scarffe JH. Double-blind placebo controlled study of vancomycin prophylaxis for central venous catheter insertion in cancer patients. J Hasp Infect 1990; 15: 95-102.
