A New Vascular Access Catheter for Hemodialysis

A New Vascular Access Catheter for Hemodialysis

A New Vascular Access Catheter for Hemodialysis Robert Uldall, MD, FRCP, FRCP(C), Michael DeBruyne, BSME, Marlene Besley, RN, Janice McMillan, RN, Mar...

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A New Vascular Access Catheter for Hemodialysis Robert Uldall, MD, FRCP, FRCP(C), Michael DeBruyne, BSME, Marlene Besley, RN, Janice McMillan, RN, Martin Simons, MD, BSc, FRCP(C) and Robert Francoeur, COP • A new vascular access catheter has been developed (Cook Critical Care, Bloomington, IN) that is suitable for both short-term and long-term hemodialysis. Designed primarily for the internal jugular vein, it emerges through a subcutaneous tunnel on the anterior chest wall. With parallel cylindrical lumens to provide blood flows of 400 mL/min, it is compressible during insertion and can be placed percutaneously in the vein through a 13-French peel-away sheath. This allows repeated insertions at different times in the same patient. In 80 catheter insertions, we have found one case of jugular vein thrombosis attributable to the catheter and no subclavian vein thrombosis. After 15 months of use, the bloodstream infection rate was one per 19.7 patient-months. Using this device, it should be possible to stop the subclavian vein damage and perforating injuries that have been the most important complications of semistiff, tapered, subclavian catheters. © 1993 by the National Kidney Foundation, Inc. INDEX WORDS: Vascular access catheter; hemodialysis.

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EMPORARY VASCULAR access for hemodialysis has for the last 10 years largely relied on percutaneously inserted dual-lumen, semistiff, tapered catheters inserted by the subclavicular approach to the subclavian veins. The advantages and especially the convenience of this method have been fully described elsewhere. 1,2 However, despite warnings in the literature on how to avoid injury to patients,3 there continue to be deaths from perforating injuries, a danger inherent in the catheter design. 4,5 More importantly, there continues to be a high incidence of subclavian vein thrombosis and stenosis. 6 A number of investigators have suggested that internal jugular cannulation may be safer than subclavian cannulation for both short-term7,8 and long-term vascular access,9,10 but up to now a catheter has not been available that is suitable for short-term or long-term percutaneous insertion in the jugular vein. Standard tapered dual-lumen catheters, which cannot be turned through 180 0 to be tunneled onto the anterior chest wall, have to be left protruding in the supraclavicular area of the neck. The Quinton PermCath (Quinton Instruments, Seattle, W A), a soft silastic catheter with two cyFrom The Toronto Hospital, Western Division University of Toronto, Toronto, Canada. Received August 21, 1992; accepted in revisedform November 19, 1992. Address reprint requests to Robert Uldall, MD, FRCP, FRCP(C), Nephrology Division, Wellesley Hospital, 160 Wellesley St E, Toronto, Ontario, M4Y 1J3 Canada. © 1993 by the National Kidney Foundation, 1nc. 0272-6386/93/2103-0005$3.00/0 270

lindricallumens and open-end apertures in a soft blunt tip, has proven extremely effective for longterm use in the jugular site, but suffers from the disadvantage that it requires skilled and timeconsuming surgical insertion. 10 Once removed, a PermCath is difficult to insert surgically in the same vein a second time. Thus, it is unsuitable for the majority of cases that require temporary vascular access. Our purpose has been to develop a catheter that would be suitable for percutaneous insertion in the jugular vein. Ideally, this device would have two cylindrical lumens and end apertures in a floppy, soft, blunt tip, which would be incapable of causing penetrating injuries to the superior vena cava or right atrium. The catheter should be capable of being turned through 180 0 over the top of the clavicle to emerge through a subcutaneous tunnel on the anterior chest wall. It should be suitable for short-term access in patients who require temporary periods of hemodialysis of a few weeks, and also for long-term access in patients in whom conventional vascular access has failed. It should provide blood flows of 400 mLI min to allow maximally efficient dialysis. We envisaged that such a catheter could also be used in the femoral vein, tunneled to emerge on the anterior aspect of the thigh. A highly flexible catheter, used in this way, could probably be left in the femoral site for several weeks or months, although the potential problems of thrombosis and infection at this site would have to be monitored closely. Preliminary experience with four patients who had femoral catheters for up to 23 months will be extended before it becomes the subject of a separate report.

American Journal of Kidney Diseases, Vol 21, No 3 (March), 1993: pp 270-277

VASCULAR ACCESS CATHETER

By avoiding the use of the subclavian vein for temporary vascular access, it should be possible to prevent almost entirely the disability caused by subclavian vein thrombosis and stenosis. This report describes the features and performance of the catheter we have developed to fulfill the aims described above. We report initially our experience with the catheter in the jugular site.

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a

METHODS

Description of the New Catheter The new catheter (Cook Critical Care, Bloomington, IN), constructed from soft white radio-opaque silastic, has two equal cylindrical lumens situated side by side and is designed to provide blood flows of 400 mL/min with arterial and venous pressures less than 250 mm Hg. The unique feature of the catheter is the design of the distal section. This section may vary in length from 9 to 15 cm depending on the total length of catheter required for the individual patient. The distal section is designed to be collapsible so that it can be passed easily through a 13-French Cook peel-away sheath. The arteriallumen is thick-walled to provide resistance to negative pressure, and the venous lumen is thin-walled, but strong enough to withstand positive pressure (Fig la). To pass the distal portion of the catheter through the peel-away sheath, the thin-walled venous lumen can be compressed against the side of the thickwalled lumen and the catheter will slide through the sheath in its collapsed state (Fig I b). Once the catheter is through the sheath, the sheath can be peeled away and the catheter returns to its former shape. The upper or proximal section of the catheter, which is 17 cm in length, has basically the same cross-sectional shape as the PermCath (Fig Ic). This proximal section is tapered down onto the distal section so that once the distal section is in the vein, the proximal section can follow by gentle dilatation. The thick-walled negative pressure lumen is mounted on a relatively stiff obturator. This serves to keep the catheter stretched out straight while it goes through the sheath. Once the catheter is fully into the vein, the obturator is simply removed together with the guidewire. Finally, in contrast to conventional catheters in which the arterial lumen stops short of the venous (the venous return being somewhat longer to reduce recirculation), in our catheter, arterial blood is extracted through the thick-walled lumen that protrudes beyond the venous. Venous blood is ejected through the thin-walled lumen at a level I cm higher than the arterial (Fig 2). Logically, this configuration should discourage accumulation of thrombus in the angle between the two lumens. The potential disadvantage is a higher rate of recirculation. We felt that a reduced rate of thrombus obstruction was more important than a slight difference in recirculation rate. Although the thin-walled lumen has been designed for a positive pressure venous return, it is still possible to reverse the flows and use it as a negative-pressure arterial outflow. In practice, a negative pressure greater than 350 mm Hg is required before the thin-walled lumen collapses. Blood is extracted from the patient through whichever lumen gives the best flow. The catheter is available in different lengths from 26 cm, in 2-cm increments, to 32 cm. A 26-cm catheter is

b

c Fig 1. (a) Cross-sectional shape of the distal end of the Cook catheter. (b) Catheter is compressed to go through the peel-away sheath. (c) Cross-sectional shape of the proximal part of the catheter.

most commonly used on the right side and a 30-cm catheter on the left. With a lO-cm subcutaneous tunnel and the hub of the catheter close to the exit site on the chest wall, the tip will usually lie just inside the entrance to the right atrium. The longer catheter on the left side allows for the greater distance required to travel to reach the entrance to the right atrium. The catheter is not suitable for and should not be used for subclavian cannulation.

The Internal Jugular Site The internal jugular site is probably the site of choice in patients in whom the catheter is being planned as a permanent access because of inability to create an arteriovenous fistula. In this situation, it has replaced the PermCath in our program. Advantages over the PermCath are ease of introduction by the percutaneous technique and the ability to use the same site again if and when the catheter is removed and left out. This is difficult with the PermCath. With the Cook Catheter, we have performed repeated cannulations in the same internal jugular vein, as many as four separate insertions in one vein. In the internal jugular site, the position of the catheter is the same as with the PermCath. The main difference is the

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routine practice to use Doppler ultrasound to demonstrate the patency and exact location of the internal jugular vein in relation to the surface markings before starting the procedure. A vertical mark is made on the neck over the vein above the clavicle while the head is turned to the opposite side. If possible, the operator is in attendance during this process. 2. Making the tunnel. Once the entry position to the vein is known, the subcutaneous tunnel is made slightly lateral to this so that the catheter coming up through the tunnel can be turned gently medially to enter the vein between the two heads of the sternomastoid. The tunnel goes downwards to a skin exit site approximately 10 cm below the clavicle (Fig 3). The site of the tunnel is first infiltrated with local anaesthetic. The tunneling is done in the deep subcutaneous tissue using a curved hemostat, (mosquito forcep) starting inside the incision and bringing the tips of the curved hemostat out through the skin. 3. Bringing the catheter up through the tunnel. Each catheter is provided with a semistiff obturator, which, after being lubricated with the sterile water-soluble lubricant provided, should be inserted and locked into the arterial (redcoded) limb of the catheter to stiffen it during its passage through the Cook peel-away sheath. The catheter is soft and fragile and cannot simply be pulled through the tunnel with a curved artery forcep. Instead the catheter is drawn up through the tunnel inside a 13-French, 15-cm Cook peel-away sheath. When this sheath is pulled through the tunnel, the catheter slides through with it, without being damaged. A clamp is now placed across the venous (blue-coded) clamping limb of the catheter. This prevents unnecessary blood loss through the venous lumen when the catheter first enters the vein. 4. Anchoring the catheter. The catheter does not have a fixed Dacron cuff. Instead it has a grommet that is slid onto the catheter after it has been brought up through the tunnel and can be moved into any position on the catheter. This is done by moving it along the catheter until it is lying on the

Fig 2. Intended direction of blood flow for the new Cook catheter. Blood is drawn in through the longer thickwalled lumen and discharged through the shorter thinwalled lumen. In practice, the flows can be reversed so as to use whichever lumen delivers the best flow.

ease of the percutaneous technique compared with the considerable technical difficulty of the surgical technique.

The Steps in the Percutaneous Technique 1. Preparing to enter the vein. This requires an incision not less than 3 cm in length. For the internal jugular insertion, it is just above the clavicle and at right angles to the sternomastoid muscle. Entrance to the jugular vein is in the gap between the two heads of the sternomastoid. It is now our

Fig 3. Position of the Cook catheter in place in the right internal jugular vein. The grommet anchors the catheter under the incision above the clavicle.

VASCULAR ACCESS CATHETER catheter level with the incision. The grommet grips the catheter rather like a tennis wristband. It has narrow wings with holes in them for anchoring to the soft tissues. An encircling ligature around each end of the grommet holds it securely on the catheter so that the catheter cannot slide out of it (Fig 4). The idea is to fix the grommet to the soft tissues under the incision before the incision is finally closed, thus preventing the catheter from sliding in or out. If it is always positioned under the incision, it can always be released by opening the same incision. This avoids the necessity for an extra incision (often needed to locate a Dacron cuff). 5. Introducing the guidewire. We recommend that a 21gauge needle be used to locate the vein first. Then a 2-in gauge 18 Cook Seldinger needle is used to enter the vein. It is important to avoid puncturing the vein too close to the upper border of the clavicle. This is because there is some tough ligamentous fascia in this area through which it will be hard to pass the soft catheter. Even half a centimeter above the clavicle, the tissues part easily to allow entry of the catheter. A standard 0.038 J-tipped guidewire, 70 cm in length, is introduced and passed down into the right atrium. We have learned previously that straight soft-tipped guidewires can perforate the heart." J-tipped guidewires do not perforate the heart or vein walls, and the depth to which they are inserted is not critical as long as the tip enters at least as far as the right atrium. 6. Inserting the catheter in the vein. This is done with a separate 13-French Cook peel-away sheath. The sheath is provided with each catheter and is 8 cm in length. The peel-away sheath is mounted on a dilator and provided with a valve to be placed at its proximal end to prevent bleeding when the dilator is removed. This allows the operator to perform the whole procedure single-handedly. The patient must be head down during the short time it takes to insert the catheter; otherwise there is a danger of air embolus through the wideopen sheath. A deep inspiration performed while the sheath is open could theoretically lower intrathoracic pressure enough to draw air into the vein. It is therefore wise to ask a cooperative patient to hold his breath in inspiration during the period when the sheath is open. First, the dilator and sheath with its valve are passed down into the vein over the guidewire. When the sheath can go no further, the dilator is removed over the guidewire, leaving the valve and guidewire in place. As the dilator is removed, the valve closes over the guidewire and occludes the proximal end of the sheath to prevent back-bleeding from the vein. Now the operator can use both hands to thread the proximal end of the guidewire down through the thick-walled lumen ofthe catheter, which contains the obturator. Once the guidewire emerges through the arterial limb, it can be clamped to prevent it from slipping back in. The distal end of the catheter can now be passed through the valve and through the sheath into the vein. Once the catheter is through the sheath as far as the junction with the proximal smooth section, the valve can be removed and the peel-away sheath can be peeled off. Care is taken not to let the catheter slip out as the sheath is being peeled off. In practice, it works best if the operator alternately peels away the sheath, then advances the catheter, until the sheath is peeled away completely.

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Fig 4. Method for anchoring the grommet on the Cook catheter with a suture tied round each end and the grommet secured to the adjacent soft tissues.

Once the sheath is gone, the catheter can be slid all the way into the vein. The circumference of the catheter will stretch the aperture in the vein wall and no bleeding will occur. The guidewire and then the obturator can then be pulled back out of the catheter. Both lumens of the catheter are aspirated and flushed. 7. Positioning the catheter tip. Whether the catheter is being inserted from the left or the right, the ideal position for the tip is just inside the entrance to the right atrium. If it is too far above the right atrium, the flow is less reliable. If it is too far into the right atrium, it may interfere with the tricuspid valve. The position should therefore be checked after insertion, either by fluoroscopy or by x-ray. Insertion under fluoroscopy makes positioning easy, but most nephrologists do not have easy access to fluoroscopy. If the operator is not confident of the position, the final fixation may be delayed until the Xray has been taken. With practice, one learns to judge the right position for the catheter tip in the majority of cases without x-ray or fluoroscopy, simply confirming the position with a chest x-ray when the procedure is over. A 26-cm catheter is appropriate for the right internal jugular vein in an average person if a 10-cm subcutaneous tunnel is made.

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8. Fixation and closure. The holes in the wings of the grommet should be sutured to the sternomastoid muscle with 3-0 black silk (Fig 4). When the catheter has to be removed, it can be done by simply pulling it out as with any temporary catheter. The intention is that the sutures will tear out of the wings and the grommet will slide out with the catheter. Black silk sutures left behind when an uninfected catheter was removed have not caused any problems. If the grommet remains behind, it can be removed later. Care is always taken to remove infected catheters totally. Closure of the incision is best done with two or three subcutaneous absorbable sutures followed by a continuous 4-0 skin suture. The dressing is with the double OP-SITE technique, I using any of the approved transparent sterile dressings. The wound should be covered with gauze and another transparent dressing to keep the gauze in place.

Heparinization The internal dead space of each limb of the commonly used 26-cm catheter is just over 1.4 mL. Each limb should be filled immediately after insertion with 5,000 U heparin contained in a total volume just less than this to avoid spilling heparin into the general circulation. Thereafter, we use a volume of 1.5 mL after each dialysis. Longer catheters have a slightly greater internal volume. The internal volume of the dead space is marked on each catheter tray.

Maintenance of Patency As with our previous experience with PermCaths, we use warfarin to prevent thrombus obstruction in patients whose catheters tend to clot. We have also used intravenous bolus doses of urokinase 250,000 U to reestablish blood flow in cases where flow was inadequate. '2

Recirculation Studies Recirculation studies were performed in a number of patients, within 15 minutes of the beginning of dialysis, at 300 mL/min and 400 mL/min. These were performed during conventional flow using the thick-walled lumen for outflow and the thin-walled lumen for venous return. They were also done with the flows reversed whenever possible. Blood samples for urea estimation were taken simultaneously from the arterial and venous blood lines and from a peripheral vein. Recirculation was calculated using the formula: ([P - A]/[P - V]) X 100 = % recirculation, where A is the urea concentration in the arterial line, V is the urea concentration in the venous line, P is the urea concentration in the peripheral vein.

were administered and the catheter was removed as soon as possible.

Checking for Thrombosis and Stenosis of Veins All patients have had serial Doppler ultrasound studies to monitor the patency of the cannulated veins. Seventeen patients also had enhanced computed tomographic (CT) scans of the neck to confirm patency of the internal jugular vein.

RESULTS

During 15 months between the end of November 1990 and the end of February 1992, 80 catheters were inserted by one operator (R.D.) into 65 patients with end-stage renal failure in four different hospitals, 67 into the right and 13 into the left internal jugular vein. Five patients had catheters at different times in both jugular veins. The same vein was cannulated more than once in six patients, and one vein was successfully cannulated on four different occasions without jugular vein thrombosis. The indications for insertion are shown in Table 1. The duration of the insertions was up to 15 months, with a total of 243 patient-months. The patients ranged in age from 21 to 87 years, with a mean of 55.3 years. All insertions have been technically successful except in three instances in which the internal jugular vein was found to have been previously thrombosed and one patient who was found to have an anomalous left-sided superior vena cava. During the course of the 80 catheter insertions, there were five occasions when the patient had to be moved from the hemodialysis procedure room to an angiography suite in the x-ray department to allow the guidewire to be manipulated correctly into the right atrium. There have been two traumatic complications. One patient sustained a small traumatic pneuTable 1. Percutaneous Jugular Catheters: Indications For Insertion No. of No. of Patients Catheters

Eradication of Infection As with the PermCath, we administer an appropriate antibiotic and change the catheter over a guidewire to eradicate bloodstream infection in patients who have a clean exit site. 13 For exit-site infections without septicemia, we administer antibiotics and change the catheter later once the infection is clinically eradicated. Our experience has shown that after an exit-site infection has cleared, the catheter itself may reinfect the tunnel unless it is changed for a new one. When septicemia occurred in the presence of pus at the exit site, antibiotics

Permanent access Refractory vascular access Inability to tolerate a high-flow fistula Other (refused fistula) Temporary access While waiting for creation or repair of peripheral access Total

43

55 1

2 20 65

22

80

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mothorax that required no treatment during an attempt to cannulate the internal jugular vein, which was later found to be absent. A preliminary ultrasound examination had not been performed. A second patient sustained a small mediastinal bleed as a result of perforating the innominate vein with a dilator during an attempt to dilate the passage into the jugular vein. This was the case that taught us not to attempt cannulation too close to the upper border of the clavicle. One catheter slipped out during the first night due to failure of adequate fixation and one was pulled out during the first night by the patient. Seven other catheters have been pulled out by patients. Bleeding was minimal in all of these cases. If these cases are excluded, the duration of insertion has ranged between 0.3 and 15 months in the 50 patients for whom we have detailed records. The same internal jugular vein has been cannulated twice in six patients, three times in two patients, and four times in one patient. No difficulty was encountered during repeated cannulations. Blood flows of 400 mL/min with arterial and venous pressures less than 250 mm Hg have been achieved with all of the catheters, but not necessarily at every dialysis. Warfarin has been used to assist the maintenance of patency in 18 of a total of25 patients dialyzed at the Toronto Western Hospital as of December 31, 1991. Bolus doses of intravenous urokinase 250,000 U have been administered to 18 of the 43 patients who were monitored over a IS-month period at the Toronto Western Hospital.

Recirculation Studies The results of recirculation studies on patients monitored at Toronto Western Hospital are shown in Table 2. Recirculation averaged 17.5% at 300 mL/min and 20.7% at 400 mL/min using the longer lumen for arterial outflow. Recirculation averaged 11.9% at 300 mL/min and 12.6% at 400 mL/min using the shorter lumen for arterial outflow. No correlation could be found between recirculation and the position of the catheter in relation to the vein wall or the right atrium.

Injection Changing the catheter over a guidewire during antibiotic therapy has been used in six cases to

275 Table 2. Recirculation in Cook Catheters Blood Pump Speed 300 mL/min

Direction of Flow

Blood removed through longer lumen Blood removed through shorter lumen

400 mL/min

No. of Percent No. of Percent Tests Recirculation Tests Recirculation

19

17.5

19

20.7

24

11.9

19

12.6

eradicate bloodstream infection and in four cases to eradicate an exit-site infection. Eleven catheters have had to be removed completely. Five of these were for exit-site infection that failed to respond to antibiotic therapy. Six catheters were removed when septicemia was accompanied by pus at the exit site. The bloodstream infection rate during the 15month experience was one per 19.7 patientmonths. One patient developed a pyogenic arthritis of the left shoulder during the course of septicemia, which settled when the catheter was removed and antibiotics were administered.

Results of Radiologic Imaging Studies Doppler ultrasound studies performed on 25 patients who received jugular catheters at Toronto Western Hospital found one case of internal jugular vein thrombosis. This was confirmed by an enhanced CT scan of the neck. Two other patients had an apparent stenosis of the jugular vein at a site other than that of insertion. These three patients all underwent magnetic resonance imaging (MRI) to look for evidence of intracerebral venous thrombosis. All of the MRI studies were negative. There appeared to be no intracerebral venous thrombosis. DISCUSSION

The first 15 months' experience with this device show that the aims have been achieved to a large extent. A new catheter has been designed, manufactured, and tested and found to be suitable for percutaneous insertion in the internal jugular vein. Eighty catheters have been inserted with only two minor traumatic complications

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and no catheter-related deaths. With our present knowledge, both of these complications could have been prevented. In contrast to the experience with semistiff, tapered catheters, which have caused delayed perforating injuries long after the insertion procedure,4,5 this blunt-tipped catheter has not caused nor seems likely to cause any trauma. We believe that successful cannulation has been assisted by the use of preliminary ultrasound guidance. Denys et al in a controlled trial of the use of ultrasound versus surface markings showed a 95% success rate in first-attempt cannulation compared with 33% using surface markings only.14 Nine catheters have either slipped out or been pulled out by confused patients, but in every case blood loss was minimal, probably because of the long subcutaneous tunnel. The same vein can be cannulated repeatedly and without difficulty for separate insertion episodes. Infection rates are clearly superior to those seen with temporary subclavian catheters 15 and are comparable to the best reported series with longterm jugular catheters. 16 Blood flows of 350 to 400 mL/min can be obtained at nearly every dialysis provided that thrombosis formation around the catheter can be prevented. Whenever the blood flow was less than this, the problem was correctable by administration of intravenous urokinase 250,000 U. In patients who require urokinase on more than one occasion, we have usually resorted to warfarin therapy for prevention of thrombus formation. 12 Despite the unconventional configuration of the arterial and venous end-apertures, the opposite of normal, the recirculation rates have generally been acceptable. Although the longest duration of insertion (the first of these catheters to be inserted) is, at the time of submitting this report, still only 23 months, it seems unlikely that the catheter will function any less well for long-term use than the PermCath. It may turn out that the most important advantage of this device is that it does not cause subclavian vein damage. In the limited experience of 80 catheters placed during the first 15 months, there has been no evidence of subclavian vein thrombosis attributable to the catheter and only one case of internal jugular vein thrombosis so far. Stenosis of the internal jugular vein cannot be ruled out by enhanced CT scans of the neck

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or by ultrasound. It is possible that stenosis would be discovered by internal jugular venograms, but these are technically difficult to perform as we have discovered in a previous study (as yet unpublished). Nevertheless, these initial results tend to confirm our previous experience and that of others that jugular catheters cause little damage to jugular veins. I? Whether this percutaneously inserted catheter causes less jugular vein damage than those which are surgically inserted seems likely, but further long-term observation will be required to confirm whether this is so. The new Cook catheter has replaced the PermCath in our program for patients in whom conventional vascular access was no longer possible, the main advantages being ease of insertion by operators other than vascular surgeons, and the ability to insert the catheter just as easily a second time for a separate cannulation episode if the first catheter has to be completely removed. Our prediction is that the insertion and catheterchanging procedures will, in most centers, be most frequently performed by interventional radiologists with easy access to fluoroscopy. We are also now advocating the use of the catheter for all patients with end-stage renal failure who do not have a working fistula. It will provide immediate and continuing access until a fistula can be constructed and has time to mature. By avoiding subclavian cannulation, it should be possible to avoid completely subclavian vein thrombosis and stenosis, which are proving to be such a disability in patients with a fistula in the ipsilateral arm. For the same reasons, it would be logical to use it during all episodes of temporary fistula failure until a new fistula can be constructed or an occluded fistula can be repaired. The slightly increased time and effort required to insert the catheter, compared with subclavian cannulation, can be justified if one can thereby avoid permanent subclavian vein damage. Other indications are patients on long-term peritoneal dialysis who need temporary hemodialysis to rest the peritoneal cavity during treatment of peritonitis. Such patients may need hemodialysis in the future and there is an obligation to avoid damage to their subclavian veins. Whether the catheter has any role in the management of acute, reversible renal failure is less clear. In such cases, vascular access is usually re-

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quired for only 2 to 3 weeks, and subclavian vein damage is less serious in a patient who will not need hemodialysis in the future. Vascular access for acute renal failure is often required at short notice and at times when more skilled operators are not available. For such indications, conventional subclavian or femoral cannulation may be considered quicker and easier. In this clinical setting, a jugular catheter with a soft blunt tip may still justify itself in the long-term because of reduced danger of perforating injuries of the wall of the superior vena cava. ACKNOWLEDGMENT The authors wish to thank all the nursing staff at The Toronto Western Hospital for their dedicated help in the introduction of this new technique. We are also grateful to Victoria Moniz and Irene Cadonic for preparation of the manuscript.

REFERENCES I. Uldall PR, Dyck RF, Woods F, Merchant N, Martin

GS, Cardella CJ, Sutton D, deVeber G: A subclavian cannula for temporary vascular access for haemodialysis and plasmapheresis. Dial Transplant 8:963-968, 1979 2. Uldall PR: Subclavian cannulation for hemodialysis: The present state of the art. ArtifOrgans 6:73-76, 1982 3. Tapson JS, U1dall PR: Avoiding deaths from subclavian cannulation for haemodialysis. Int J ArtifOrgans 6:227-230, 1983 4. Barton BR, Hermann G, Weil R: Cardiothoracic emergencies associated with subclavian hemodialysis catheters. JAMA 250:2600-2662, 1983 5. Tapson JS, Uldall PR: Fatal hemothorax caused by a subclavian hemodialysis catheter. Arch Intern Med 144:16851687, 1984 6. Brady HR, FitzCharies B, Goldberg H, Huraib S, Richardson T, Simons M, Uldall PR: Diagnosis and management

277 of subclavian vein thrombosis occurring in association with subclavian cannulation for haemodialysis. Blood Purif7:210217,1989 7. Watson AR, Bahoric A, Wesson D: A central venous (WBW) catheter for multipurpose vascular access in children. ArtifOrgans 10:59-61, 1986 8. Canaud B, Beraud JJ, Joyeux H, Mion C: Internal jugular vein cannulation using two silastic catheters. Nephron 43: 133-138, 1986 9. Donnelly PK, Hoenich NA, Lennard TWJ, Proud G, Taylor RMR: Surgical management of long-term central venous access in uraemic patients. Nephrol Dial Transplant 3: 57-65, 1988 10. Blake PG, Huraib S, WuG, Uldall PR: The use of dual lumen jugular venous catheters as definitive long-term access for haemodialysis. Int J ArtifOrgans 13:26-31, 1990 11. Blake PG, Uldall PR: Cardiac perforation by a guidewire during subclavian catheter insertion. Int J Artif Organs 2:111-113, 1989 12. Uldall PR, Besley ME, Thomas A, Salter A, Nuezca LA, Vas M: Maintaining the patency of double-lumen silastic jugular catheters for hemodialysis access. Int J Artif Organs 15:12-15,1993 13. Carlisle E, Blake PG, McCarthy F, Vas S, Uldall PR: Septicemia in long-term jugular haemodialysis cathetersEradicating infection by changing the catheter over a guidewire. Int J ArtifOrgans 14:150-153, 1991 14. Denys BG, Uretsky BF, Reddy PS, Ruffner RJ, Sandhu JS, Breishlatt WM: An ultrasound method for safe and rapid central venous access. N Eng! J Med 324:566,1991 (letter) 15. Levin A, Mason AJ, Jindal KK, Fong IW, Goldstein MB: Prevention ofhaemodialysis subclavian vein catheter infections by topical povidone-iodine. Kidney Int 40:934-938, 1991 16. Shusterman NH, Kloss K, Mullen JL: Successful use of double-lumen, silicone rubber catheters for permanent haemodialysis access. Kidney Int 35:887-890, 1989 17. Cimochowski GE, Woley E, Rutherford WE, Sartain J, Blondin J, Harter H: Superiority of the internal jugular over the subclavian access for temporary dialysis. Nephron 54:151-161, 1990