Thromboembolic complications with silicone elastomer subclavian catheters

Long-term stable modifications of silicone elastomer for improved hemocompatibility

Silicone elastomers are well established in medical engineering and particularly in blood-contacting applications such as catheters and medical tubing. Still, their intrinsic surface properties have potential for improvement. For example, hydrophobicity reduction can be a way to provide better hemocompatibility. In this study, several bulk and surface modifications of silicone elastomers using polyethylene glycol (PEG) were investigated. All modifications induced long-term (2 months), stable wettability of the surface. Moreover, cytotoxicity testing demonstrated their suitability as implant material. Hemocompatibility was investigated through a thrombin generation assay as well as a platelet adhesion study combining an enzymatic assay and a scanning electron microscope analysis. That the hemocompatibility of silicone was considerably improved thanks to the PEG modifications could be shown. The study introduces easily processable, cost-efficient, and long-term stable hydrophilic modifications of silicone elastomer for improved hemocompatibility.

Central Venous Catbeterization: A Comprehensive Review, Part II

In Part I of this article, the indications and contraindica tions of central venous catheterization were reviewed, and the antecubital, external jugular, and femoral vein routes discussed. In Part II, the internal jugular and sub clavian vein routes for central venous catheterization are reviewed, and an overview of catheter maintenance and infection control presented. The internal jugular vein and subclavian vein are the two most useful sites for central venous access. There is greater experience with the subclavian vein, and it is largely because of a perceived high complication rate associated with this approach that the internal jugular vein was cultivated as an access route in adults. The debate remains as to which route is preferable. In reality, each method has advantages in a given clinical situation.

Low-dose warfarin does not decrease the rate of thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy, radiation, and erythropoeitin

OBJECTIVES

We had previously reported an association between the use of recombinant human erythropoietin (rHuEPO) and thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy and radiation. We hypothesized that low-dose warfarin would be effective prevention for thromboembolic events in this setting.

METHODS

A retrospective analysis of patients with cervical or vulvo-vaginal carcinoma receiving chemoradiation and rHuEpo was performed. Thirty-two patients received rHuEpo alone, and 24 received warfarin (1-2 mg) and rHuEpo. The primary endpoint was objectively proven symptomatic venous thrombosis.

RESULTS

There was no difference in the baseline characteristics (e.g. age, stage, body mass index, mean and peak hemoglobin, WBC and platelet counts, and number of transfusions) between these two groups. The rate of thrombosis also was not statistically different (P = 0.62). Nine of 24 patients had a symptomatic deep vein thrombosis (DVT) while receiving warfarin compared to 10 of 32 patients not on warfarin. There was no difference between the two groups in the percentage of patients with upper extremity DVT (P = 0.83) or lower extremity DVT (P = 0.64).

CONCLUSION

Daily low-dose warfarin did not alter the incidence of symptomatic DVT in patients with cervical or vulvo-vaginal cancer who received rHuEpo in conjunction with chemoradiation.

Prophylaxis of central venous catheter-related thrombosis with minidose warfarin in patients treated with high-dose chemotherapy and peripheral-blood stem-cell transplantation: retrospective analysis of 228 cancer patients

Patients with a central venous catheter (CVC) undergoing high-dose chemotherapy (HDC) followed by peripheral-blood stem-cell transplantation (PBSCT) for malignancies are at high risk of thrombosis, but the use of anti-coagulant prophylaxis remains debatable in this setting of patients. We analyzed the efficacy and the safety of minidose warfarin in 228 patients in whom CVCs had been placed and who had received 292 HDC courses of therapy. The catheters remained in place for a mean of 173 (range 40-298) days. All patients received prophylactic oral warfarin in the fixed dose of 1 mg/day starting on the day of CVC insertion. Prophylaxis was interrupted during aplasia when platelet counts fell below 50,000/dL. There were no toxic deaths related to the prophylaxis. Overall there were 4 thrombotic events. Three occurrences were directly related to the catheter, while the remaining event was a deep saphenous-vein thrombosis. A number of potential predictive factors were analyzed for their impact on thrombotic events without finding any significant correlation. Four episodes of bleeding occurred, with each of these individuals having a normal INR but a platelet count below 50,000/dL. Minidose warfarin is effective and safe to use for preventing thrombotic events in this setting of patients.

Prevalence of inherited prothrombotic abnormalities and central venous catheter-related thrombosis in haematopoietic stem cell transplants recipients

In this prospective study, we assessed the incidence of central venous catheter (CVC)-related thrombosis in haematopoietic stem cell transplant (HSCT) recipients. We determined the contribution of inherited prothrombotic abnormalities in blood coagulation to CVC-related thrombosis in these patients. The study was conducted between May 2002 and September 2004. CVCs were externalized, nontunneled, polyurethane double lumen catheters. Before catheter insertion, laboratory prothrombotic markers included factor V Leiden, the prothrombin gene Gly20210A mutation, plasma antithrombin levels, and protein C and S activity. All patients were systematically examined by ultrasonography just before, or <24 h after, catheter removal, and in case of clinical signs of thrombosis. A total of 171 patients were included during the 28-month study period. Five (2.9%) and three (1.7%) patients had evidence of protein C and protein S deficiency, respectively. Only one patient had an antithrombin deficiency (0.6%). In total, 10 patients (5.8%) were heterozygous for the factor V Leiden mutation, and one patient had heterozygous prothrombin G20210A mutation (0.6%). We observed a CVC-related thrombosis in 13 patients (7.6%). Thrombosis was diagnosed in four out of 20 patients (20%) with a inherited prothrombotic abnormality compared to nine of 151 patients (6%) who did not have a thrombophilic marker (relative risk 3.3 CI 95% 1.1-9.9). Our results suggest that inherited prothrombotic abnormalities contribute substantially to CVC-related thrombosis in HSCT recipients. In view of physicians' reluctance to prescribe prophylactic anticoagulant treatment in these patients, a priori determination of inherited prothrombotic abnormalities may form a basis to guide these treatment decisions.

Stability of plasma-treated silicone rubber and its influence on the interfacial aspects of blood compatibility

Medical-grade polydimethylsiloxane elastomer was subjected to low-powered plasma treatment in the presence of four different gases: O(2), Ar, N(2) and NH(3). Changes to the surface chemistry immediately after processing and the stability of the treatments following ageing in phosphate buffered saline or air for up to 1 month were investigated using X-ray photoelectron spectroscopy and dynamic contact angle analysis. Changes in surface morphology were assessed using optical microscopy and atomic force microscopy. All treatments resulted in an increase in wettability, attributed to major changes in chemistry combined with modest etching. Furthermore, the primary site of attack of the plasma species appeared to be dependent upon the feed gas implemented. The two main chemical changes observed after ageing were due to reactions with the storage media and relaxation processes resulting in further changes in wettability. The influence of the surface modifications on the blood compatibility of the materials was investigated by assessing contact phase activation using a partial thromboplastin time assay. It was demonstrated that the O(2) and Ar plasma treatments reduced the performance of the silicone but the N(2) and NH(3) treatments had a significantly beneficial effect on the activation of the coagulation cascade.

Vascular access for dialysis in the intensive care unit

Management of the vascular access (VA) for renal replacement therapy (RRT) in acute renal failure (ARF) patients is faced with a twofold problem: first, the creation of an angio-access that is adequate for RRT in the acute setting; second, the preservation of the patient's vascular network in order not to preclude further use of the vessel in the event of evolution to chronic renal failure. Central venous catheters are the preferred VA for RRT in the intensive care setting. Semi-rigid double-lumen polyurethane catheters may be considered for short-time use (up to 2-3 weeks). Soft silicone double-lumen or twin-catheters, preferably with subcutaneous tunnelling, are highly desirable for prolonged RRT (over 3 weeks). The femoral route is the first option in the presence of associated risk factors (respiratory failure, pulmonary oedema, bleeding...). The internal jugular route should be considered for mid-term use in order to facilitate the patient's mobilization and to reduce the risk of infection. The subclavian route should be avoided because of the risk of stenosis and/or thrombosis of the outflow vein. Catheter insertion must be performed by a trained physician with ultrasound guidance using either skin mapping or continuous vein guidance. Catheter handling and care should comply with best practice guidelines and should be part of a continuous quality improvement programme in order to reduce catheter-related morbidity. Preservation of the upper limb vascular network of the patient consists of sparing the native vessels (artery and vein) of the patient and preserving the functionality of the permanent VA in chronic renal failure patient. This 'lifeline' of chronic renal failure patients may be maintained by preventing inflammation, infection and thrombosis of the superficial vessels of the arm and forearm of patient.

Central venous catheter occlusion and thrombosis

Central venous catheters are widely used in children with critical illness and chronic disease. These devices are often essential in the delivery of medications and intravenous fluids and in hemodynamic monitoring. Central venous catheter occlusion and thrombosis are common problems in patients using these devices. This article reviews the background, pathophysiology, and incidence of catheter occlusion and catheter-related thrombosis. Diagnostic, preventive, and treatment strategies, along with future research directions, are addressed.

Upper-extremity deep vein thrombosis

Upper-extremity deep vein thrombosis (UEDVT) was an understudied disease until recently. Previously thought of as benign, UEDVT has been shown in recent studies to pose a significant risk for pulmonary embolus and death. This article reviews the epidemiology, risk factors, clinical features, diagnostic tests, treatment options, complications, and prevention strategies for patients with UEDVT.

Minidose warfarin prophylaxis for catheter-associated thrombosis in cancer patients: can it be safely associated with fluorouracil-based chemotherapy?

PURPOSE

The use of prophylactic low-dose oral warfarin in cancer patients with a central venous catheter (CVC) in place has an established role in the prevention of thrombotic complications and is associated with a low hemorrhagic risk. Despite the literature indicating an adverse interaction between warfarin and fluorouracil (FU), the frequency of this interaction and whether it occurs when minidose warfarin is used is unknown. We analyzed the incidence of alterations in the International Normalized Ratio (INR) and bleeding in cancer patients given minidose warfarin during treatment with continuous-infusion FU-based regimens.

PATIENTS AND METHODS

Between July 1999 and August 2001, 95 cancer patients were evaluated. Forty-one patients (43%) had liver metastases. Seventy-nine patients (83%) had a Groshong CVC (Bard Access System, Salt Lake City, UT), and 16 (17%) had a Port-a-Cath device (Bard Access System). All patients received oral warfarin at a dose of 1 mg/daily as prophylaxis beginning the day after the catheter was positioned. An INR of more than 1.5 was considered significantly elevated.

RESULTS

INR elevation occurred in 31 patients (33%), with 18 patients (19%) having an INR more than 3.0. Twelve (39%) of the 31 patients had liver metastases. Bleeding was observed in eight patients (8%); seven of these patients had elevated INR levels. We observed INR elevations in 12 of 21 patients treated with a FU, folinic acid, and oxaliplatin (FOLFOX) regimen, 11 of 40 treated with a de Gramont regimen (FU and folinic acid), and five of 19 treated with a FU, folinic acid, and irinotecan (FOLFIRI) regimen.

CONCLUSION

A high incidence of INR abnormalities was observed in our cohort of patients, especially those treated with FOLFOX regimen. Clinicians should be aware of this interaction and should regularly monitor the prothrombin time in patients receiving warfarin and FU.

Factor V Leiden in central venous catheter-associated thrombosis

Subclavian vein thrombosis is a well-recognized complication following central venous catheter insertion and is associated with significant morbidity. The factor V Leiden mutation is an important risk factor for deep venous thrombosis and pulmonary embolism. Whether this mutation also predisposes patients fitted with a central venous catheter to subclavian vein thrombosis is not known. The occurrence of central venous catheter-associated thrombosis was investigated in 277 consecutive patients receiving an allogeneic bone marrow transplantation. All patients received a tunnelled double or triple catheter positioned in the subclavian vein. Catheter-associated thrombosis was diagnosed on the basis of clinical signs of thrombosis, i.e. swelling and/or redness of the limb or venous engorgement and was confirmed with a colour-flow Doppler ultrasound. Thirteen patients were heterozygous for the factor V Leiden mutation. Seven of these patients had a subclavian vein thrombosis (54%), while this occurred in only 9% of the factor V Leiden-negative patients, corresponding with a relative risk of 7.7 (95% CI 3.3-17.9). Factor V Leiden is attributable for 17.3% of all thrombosis in patients with central venous catheters. The majority of patients with the factor V Leiden mutation with a central venous catheter will develop thrombosis. Patients with a factor V Leiden mutation should receive adequate thrombosis prophylaxis upon catheter introduction and the catheter should be removed immediately after the treatment. Based on this very high risk, we advise testing for factor V Leiden in all bone marrow transplantation patients receiving a central venous catheter.

No effect of nadroparin prophylaxis in the prevention of central venous catheter (CVC)-associated thrombosis in bone marrow transplant recipients

Complications of CVCs in 382 consecutive patients receiving a stem cell transplantation (SCT) were analysed. Early complications were pneumothorax (3.6%), haematothorax (0.5%), dislocation (3%) and dysfunction (3.6%). Eighty-seven-associated infections (22%) were observed, leading to removal of the CVC in 26 patients. More bacteraemias were associated with double- or triple-lumen CVCs, 19% vs 5% in single lumen CVCs (P < 0.0001). Coagulase-negative staphylococci were the predominant microorganisms in 72%. A special point of investigation was CVC-associated thrombosis and the prophylactic value of nadroparin. Two consecutive regimens with nadroparin were used and compared; 7 days 2850 IE nadroparin and 10 days 5700 IE nadroparin. The incidence of CVC-associated thrombosis was 6.9% in 382 patients with 390 catheters. The incidence was 8% in patients receiving one of the prophylactic nadroparin regimens compared to 6% in a comparable control group without prophylaxis. A short course of nadroparin was unable to prevent thrombotic complications after discontinuation.

Prevention of central venous catheter associated thrombosis using minidose warfarin in patients with haematological malignancies

Thrombosis is a well-recognized complication following insertion of central venous catheters and is associated with significant morbidity. In an attempt to reduce line-associated thrombosis, 108 consecutive patients with haematological malignancies were commenced on prophylactic 'minidose' warfarin, 1 mg/d, at the time of line insertion. This group of patients were compared with a historic group of 115 consecutive patients who had not received warfarin. Clinically-suspected venous thrombosis was confirmed by Doppler ultrasound or venography. Patients taking prophylactic warfarin had their prothrombin time measured three times per week with the aim of maintaining an INR <1.6. Five (5%) of the 108 patients who received minidose warfarin developed a thrombosis, at a median of 72 d (range 5-166) from the time of catheter insertion. In the 115 patients who were not anticoagulated 15 (13%) developed a catheter-associated thrombosis at a median of 16 d (range 1-35). There was a significant reduction in line-associated thrombosis in patients receiving warfarin (P=0.03). These data suggest that minidose warfarin reduces the incidence of central venous catheter related thrombosis in patients with haematological malignancies.

Central venous dialysis catheter dysfunction

Central venous catheter dysfunction is a limiting factor in regard to renal replacement therapy efficiency and can thus influence patient morbidity. Early catheter dysfunction is frequently due to mechanical problems such as inadequate positioning, kinking, or constriction, but early fibrin deposition can develop soon after insertion. Delayed dysfunction usually results from thrombus formation, either within the lumen, around the catheter ("fibrin sleeve"), or in the host vein. Catheter dysfunction is suspected clinically or documented by simple imaging studies. It is usually evident and manifested by failure to aspirate blood from the lumen(s), inadequate blood flow and/or high resistance pressures during hemodialysis. However, a more subtle dysfunction may lead to a high recirculation of dialyzed blood and be overlooked if dialysis adequacy is not monitored regularly. Local instillation of a fibrinolytic agent is usually successful in restoring catheter patency. Central venous dialysis catheters present intrinsic limitations consequent to their composition and design, whereas extrinsic limitations result from site of insertion, blood properties and anatomic particularities of a given individual. These characteristics largely determine overall catheter performances. Performance parameters to consider include maximal consistently achievable blood flow rate, resistance to blood flow indicated by arterial and venous pressures during hemodialysis, and blood recirculation rate. Catheter longevity is an important consideration for cuffed catheters implanted for long-term use. The tolerated blood recirculation within central venous dialysis catheters should be below 10% to 15%, and is ideally between 3% to 7% in most clinical settings. Several recent studies confirm that short femoral catheters recirculate significantly more than is desirable. Well functioning and nonreversed internal jugular and subclavian venous catheters have, in general, recirculation rates less than 5%. With regard to various performance criteria, the TwinCath (Medcomp, Harleysville, PA) appears particularly advantageous. In any case, a good catheter maintenance program is of critical importance for the prevention and the early detection of catheter dysfunction.

Thrombotic, infectious, and procedural complications of the jugular bulb catheter in the intensive care unit

OBJECTIVE

An assessment of the thrombotic, infectious, and technical complications of continuous jugular bulb catheter monitoring in the intensive care unit (ICU) was made.

METHODS

Over a 1-year period, 44 patients suffering from traumatic brain injury, subarachnoid hemorrhage, or stroke received jugular bulb catheter monitoring in the ICU. They were followed for catheter insertion complications and the development of bacteremia. In 20 patients chosen randomly, an ultrasonographic evaluation was performed after removal of the catheter for an assessment of internal jugular vein thrombosis.

RESULTS

Of the 44 patients, 1 became bacteremic; the source was identified as a thoracostomy site. Among the complications related to the 44 catheter insertions, there were 2 instances of carotid artery puncture (4.5%), 1 misplaced catheter (thoracic placement), and 1 clinically insignificant hematoma. Of the 20 patients investigated with ultrasonography, 8 (40%) had nonobstructive, subclinical internal jugular vein thrombi after jugular bulb catheter monitoring (95% confidence interval, 19-61%). The median monitoring duration was 3 days (range, 1-6 d). No clinical factor was identified to be associated with thrombus formation.

CONCLUSION

We conclude the following: 1) the risk of bacteremia related to the jugular bulb catheter was negligible; 2) complications related to catheter insertion were rare and clinically insignificant; and 3) the incidence of subclinical internal jugular vein thrombosis after jugular bulb catheter monitoring is considerable. Although it is worthy to note this complication, no patient with a thrombus became symptomatic in the present series. The risk-benefit assessment of this monitoring technique must include consideration of subclinical thrombosis.

Normal saline versus heparin flush for maintaining central venous catheter patency during apheresis collection of peripheral blood stem cells (PBSC)

Thrombotic occlusion is frequently a complication of central venous catheters (CVCs). The original designers and producers of CVCs recommended heparin flush regimens to prevent thrombosis and maintain patency. This has become standard practice although no studies have demonstrated a relationship between heparin flushing and reduction of catheter thrombosis. Many consider the routine use of heparin flushing innocuous. However, serious complications including drug interactions and heparin induced thrombocytopenia and thrombosis syndrome (HITS) have been reported in association with heparin flushing. Numerous studies comparing heparin to saline flushing in peripheral devices suggest equal rates of thrombotic occlusions. The purpose of this study was to examine the incidence of thrombotic occlusions in CVCs using heparin compared to saline flushing. The study involved 78 cancer patients undergoing apheresis collection for peripheral blood stem cells; 29 received saline flushes and 49 received heparin (100 U/ml of saline) flushes. Study endpoints included slow apheresis flow rate (< 50 ml/min), urokinase use for thrombolysis, and radiographic evidence of catheter thrombosis. No significant differences were found for any endpoint between the two groups. These findings suggest saline may be as effective as heparin for maintaining patency of CVCs.

[Venous thrombosis on central catheters in oncology]

Central venous catheters have considerably improved the comfort and safety of chemotherapy in cancer patients. However complications as thrombosis could occur and their incidence vary from 3.7 to 42% in oncology. Catheter placement induces modifications of vascular system with formation of a fibrin sleeve and/or a mural thrombus. Thrombosis origin is linked with catheter itself, its position and the biomaterial used. Hypercoagulable state in cancer results from the perturbation of blood flow, the composition of blood itself and the vessel wall, and increases the iatrogenic effects of indwelling catheters. Finally chemotherapy used in the treatment of cancer has been associated with an increased incidence of thromboembolic events, suggesting the proposal of an antithrombotic prophylaxis in cancer patients receiving chemotherapeutic agents through indwelling catheter.

Comparison of vascular access devices

OBJECTIVE

To provide an overview of venous access device designs and methods of insertion and removal.

CONCLUSIONS

Venous access devices are indicated for many patients who require reliable long-term venous access. Three types of venous access devices are available including nontunneled, tunneled, and implanted ports. Since their introduction into clinical practice, the widespread use of these devices has had an enormous impact on cancer treatment by decreasing the overuse of peripheral veins while allowing for more flexibility and choice of the type of device used. Although numerous devices are available, each offers unique designs and performance expectations. Each type of device has similar features and can be used for intravenous drug and nutritional therapy, administration of blood products, and withdrawal of blood.

IMPLICATIONS FOR NURSING PRACTICE

Even if only a single device is used in a given setting, the nurse must have a basic understanding of all types of venous access devices. It is imperative that the nurse be fully cognizant of the anatomic position and structure of the major vessels associated with the central venous system, especially for the insertion of peripheral central catheters. Understanding the venous system and venous access design can assist in preventing or assessing potential complications.

Prolonged barbiturate therapy in a patient with closed head injury and jugular venous thrombosis

The case of a patient who sustained a severe closed head injury complicated by jugular venous thrombosis is presented. Early problems with intracranial pressure were related to bifrontal intracerebral contusions. Jugular vein thrombosis became manifest clinically late in the patient's course and was verified by Doppler ultrasonography. Late problems with intracranial hypertension were presumed to be due to decreased cerebral outflow secondary to the thrombosis. The patient required 4 weeks of a high-dose regimen of pentobarbital to control his intracranial pressure. This is an exceptionally long period of time for a patient to be in barbiturate coma for a closed head injury and still make a satisfactory recovery. The incidence, etiology, prevention, and treatment of upper extremity and jugular venous thrombosis are discussed. The ramifications of jugular venous thrombosis in neurosurgical patients are discussed.

Superior vena caval obstruction in patients with gut failure receiving home parenteral nutrition

Clinical suspicion and venographic conformation were used to diagnose 15 cases of superior vena caval obstruction (SVCO) in 107 home parenteral nutrition (HPN) patients over 379 cumulative years of HPN (3.9 cases/100 patient-years). Patients with SVCO had been on HPN a mean of 51.5 months and had used 6.2 (range 1-50) central catheters, including short- and long-term, before SVCO was diagnosed. The frequency of inflammatory bowel disease (IBD) with SVCO was approximately the same as that in our general HPN population. Positive blood cultures were present immediately preceding the diagnosis of SVCO in 40% (six of 15) of cases. Atypical line placements were noted in two cases. The most common management strategies employed were conversion to enteral feedings in five patients and placement of a new catheter directly into the right atrium by thoracotomy in another five patients. Two of the five with right atrial catheters experienced a postpericardiotomy syndrome (fever, pericardial rub, and pulmonary infiltrates) that responded promptly to indomethacin. The most significant long-term sequela of SVCO was the need for a left jugular vein to right atrial appendage bypass in one patient with chronic venous congestion from her SVCO. Once the SVCO is confirmed, systemic heparinization provides immediate antithrombotic effect and minimizes the risk of pulmonary embolism. The use of streptokinase may result in rapid thrombolysis.

Hickman catheter-induced thoracic vein thrombosis. Frequency and long-term sequelae in patients receiving high-dose chemotherapy and marrow transplantation

One hundred sixty-eight bone marrow transplant recipients and 49 patients who received high-dose chemotherapy were evaluated for symptomatic thrombosis after Hickman catheter placement. The timing of thrombotic complications was different between these two groups, with the transplant group having a significantly lower thrombus-free survival by 28 days after catheter placement. By 100 days after placement the thrombus-free survival rates of the two groups were similar. The platelet count at time of catheter placement was significantly lower in the nontransplant group, and the thrombus-free survival was longer in patients whose catheter was placed when their platelet count was less than 150,000, suggesting that thrombocytopenia delays thrombotic complications. Placement of two Hickman catheters resulted in a 12.9% thrombosis rate (21 of 162 patients) and was significantly more likely to be associated with thrombosis than placement of one catheter. Long-term follow-up evaluation of patients treated without successful fibrinolytic therapy showed no residual symptoms of venous obstruction. In those patients presenting with concomitant catheter obstruction resulting from thrombosis, low-dose fibrinolytic therapy was successful in restoring catheter function 70% of the time. Placement of two Hickman catheters is associated with an inordinate incidence of thrombosis. Thrombocytopenia at the time of catheter placement may delay this complication. Thrombotic catheter obstruction can be treated successfully with low-dose fibrinolytic therapy. Even without fibrinolytic therapy, catheter-induced subclavian vein thrombosis rarely causes long-term disability.

Deep venous thrombosis of the upper extremity: diagnosis and treatment

Deep vein thrombosis of the upper extremity was long thought to be a benign disease, rarely complicated by pulmonary embolism and associated with minimal long-term morbidity. More recent observations have demonstrated however, that a significant number of patients will continue to have disabling symptoms after treatment with conservative measures and standard anticoagulation therapy, and that pulmonary embolism can occur in the course of the disease. Because of its significant morbidity and increasing incidence, an aggressive emergency department approach to diagnosis and early consideration of fibrinolytic therapy are recommended.

Early detection and simplified management of obstructed Hickman and Broviac catheters

Thrombotic occlusion of Hickman and Broviac central venous catheters is a serious obstacle to their long-term use. Because resistance to flow (R) through a catheter of lumen radius, r, is proportional to 1/r4, we hypothesized that measurement of R would provide an objective and sensitive monitor for partial occlusions. Our measurements showed that median R at a flow of 17 mL/min was 0.7 cmH2O/mL/min in normally functioning Hickman catheters, and 4.1 cmH2O/mL/min in Broviac catheters. In obstructed catheters, which by subjective standards resisted flushing or blood withdrawal, median R was 3.0 cmH2O/mL/min for Hickman and 5.6 cmH2O/mL/min for Broviac catheters, representing significant increases. In a series of obstructed lines in which urokinase was administered, R decreased from 7.7 to 4.5 in Hickman catheters and from 5.6 to 4.2 in obstructed Broviac catheters. The elevated resistance in Hickman catheters after urokinase suggested that residual catheter obstruction was present even though catheter function returned to normal. Elevated R was seen with abnormal venograms in seven of 13 patients. Four patients had normal R values and abnormal venograms, and two patients had elevated R values with normal venograms. Measurement of resistance in Hickman and Broviac catheters provides a simple technique that can supplement or replace venography in the serial assessment and treatment of partial obstruction.

Mortality in patients on home parenteral nutrition

Fifty out of 228 patients recorded on the U.K. Home Parenteral Nutrition Register have died. The earliest to die was at 10 days following the commencement of home parenteral nutrition (HPN), and the longest to die was after 5 1/2 years. Half of the patients who died, did so within 6 months of commencing HPN. Sixty % died of their underlying disease. Most patients with scleroderma or an underlying malignancy are dead within a year of commencing HPN. In contrast, patients with Crohn's disease or the short bowel syndrome due to volvulus do well. In only 14 patients was death attributable to the administration of HPN. In this group the main causes were septicemia, SVC thrombosis, and hepatic failure. Our study suggests that HPN should be used in patients with malignancy and scleroderma only in exceptional circumstances and that further work is necessary for the prevention of SVC thrombosis.

[Tolerance of femoral vein catheterization]

The femoral vein is a convenient venous access site which has remained relatively neglected since earlier reports of major complications. However, over the last 10 years, its beneficial use for various purposes (mainly haemodialysis) justifies a reexamination of the value of femoral venous catheterization. The ease of femoral catheterization and its complications were prospectively studied in 92 intensive care patients. Of the 113 attempts made by physicians, 75% of whom were inexperienced, 103 (91.2%) were successful. Insertion resulted in 17 (15%) arterial punctures and 5 local hematomas. Seventy catheters were left in place for an average of 8.8 days. No clinical manifestations of thrombosis were observed. Bilateral phlebography was carried out before removal of the catheter in 70 cases; 45 (64%) of these controls were normal. Of the remaining 25 pathological phlebograms, there were 11 (15.7%) fibrin sleeves, 2 (2.8%) partial thromboses of the common femoral vein which could be directly linked to the venous cannulation, and various abnormalities not directly due to the catheterization (superficial femoral vein thrombosis (4), thrombosis of calf or popliteal veins (18]. One case of catheter septicaemia occurred. Microorganisms were present in 15 (18.3%) of 82 catheter cultured tips. Percutaneous catheterization of the femoral vein might therefore be considered as a good venous access route. It can be successfully used by inexperienced physicians. There is no serious risk of injury to surrounding structures and the risks of thrombosis and infection are acceptable in comparison with other routes.

Complications of intravenous feeding catheters

Complications of intravenous nutrition are uncommon but may prove problematic in patients requiring long-term nutritional support. This article reviews the complications associated with intravenous catheters with particular emphasis on problems associated with insertion, catheter-related sepsis, venous thrombosis, catheter occlusion, endocarditis and intracardiac thrombus formation.

Silicone rubber catheter venography using standard angiographic techniques

Single- and double-lumen silicone rubber central venous catheters were subjected to in vitro destructive testing. Using this data we devised a clinical technique for the detection of central venous thrombosis incorporating mechanical injection of the catheters, serial filming, and magnification radiography. In 20 patients studied, thrombosis was detected in 12 and extravasation in 3. Two partially occluded catheters burst during forceful injection. Our technique demonstrated the presence and extent of thrombosis at the catheter tip more clearly than did other venographic methods and has been especially useful in assessing the results of thrombolytic therapy.

Thrombotic complications of indwelling central catheters used for chronic hemodialysis

A new double-lumen silicone-rubber dialysis catheter, designed to be placed surgically in central veins, is now available. There is little published data concerning the long-term use of this catheter for hemodialysis, but a review of the literature suggests that pericatheter thrombus formation with or without occlusion of major veins has been a complication of chronic central venous catheterization with a variety of catheters, in both dialysis and nondialysis settings. We had this catheter placed in four diabetic patients who had severe problems related to maintenance of adequate vascular access. Two of the four patients underwent venography within 3 months of catheter placement because of impaired catheter function and were found to have thrombi on the outside of their catheters. These thrombi could not be dissolved with fibrinolytic agents, and the catheters were removed surgically without incident. The other two patients have no radiologic evidence of thrombus formation 4 and 7 months, respectively, after catheter placement. We suggest that proper selection of patients for this type of vascular access should be the subject of future studies and that patients with malfunctioning catheters undergo venography to rule out the presence of significant catheter related thrombosis.

Prevention of nosocomial infections in marrow transplant patients: a prospective randomized comparison of systemic antibiotics versus granulocyte transfusions

One hundred twelve patients with hematologic malignancies underwent marrow transplantation from HLA-matched sibling donors and were randomized to receive either prophylactic granulocyte transfusions (PG, 67 patients) or prophylactic systemic antibiotics (PSA, 45 patients) as prophylaxis against nosocomial infections. Patients were treated in conventional hospital rooms and studied until day 100 post-transplant. For the entire study period, 26 patients (39%) in the PG group developed septicemia compared to 15 patients (33%) in the PSA group. Twenty-eight patients (42%) in the PG group developed local major infections compared to 19 patients (42%) in the PSA group. Ten patients (15%) in the PG group developed viral interstitial pneumonitis compared to 6 patients (13%) in the PSA group. None of these differences were statistically significant. There was no difference in the incidence of bacterial or fungal infections or viral interstitial pneumonitis between the two groups during the granulocytopenic or post-engraftment period. There was no difference in the incidence and severity of graft-versus-host-disease (GVHD). Inability to carry out the prophylaxis was frequent in the PG group, with complications necessitating discontinuance of transfusion in 24% of the recipients and 13% of the donors. The use of PG as an infection prophylaxis modality in marrow transplantation is not supported by this study, as it is difficult to carry out and because PG did not show any advantage over the use of PSA in preventing nosocomial infections.

Internal jugular vein cannulation with two silicone rubber catheters: a new and safe temporary vascular access for hemodialysis. Thirty months' experience

Temporary and immediately usable vascular access is a vital need in treating uremic patients. Subclavian vein cannulation, although a major progress, has been associated with significant morbidity and mortality. Accordingly, for the last 2.5 years the authors have been developing an alternative technique consisting of internal jugular vein cannulation (IJVC) with two silicone rubber catheters with a long-term, proved biocompatibility. One hundred sixty-five pairs of cannulas were inserted in 153 patients. Mean duration of use was 57 days (1 day to 17 months). More than 3,000 high-performance hemodialysis sessions were performed. IJVC handling and care were easily managed by nurses. A low incidence of complications was observed: two thrombosis episodes, four skin infections with three septicemia, one air embolism, and one anaphylactoid reaction. No death was related to the technique itself. IJVC offers a new, safe, and reliable temporary vascular access immediately usable for all kinds of extracorporeal treatment.

Unusual case of central vein thrombosis and sepsis

A patient with Crohn's disease who required placement of a right external jugular vein central catheter for total hyperalimentation is presented. Catheter-induced thrombosis and catheter-associated bacteremia and sepsis subsequently developed. Following the description of the case is a brief discussion of the complications inherent in central line placement, the mechanisms by which thrombosis and sepsis occur, and the measures that can be taken to decrease the incidence of thrombosis and sepsis in central line placement. The management of central venous thrombosis and sepsis is medical and not surgical in nature, and consists of catheter removal, antibiotics, and anticoagulation.

Treatment of silastic catheter-induced central vein septic thrombophlebitis

Two patients with surgically implanted right atrial silastic catheters for home hyperalimentation developed central vein septic thrombophlebitis. Initial treatment including removal of the catheter and antibiotic therapy was unsuccessful and both patients had persistent fever and bacteremia. A clinical and microbiologic response occurred when anticoagulation therapy with heparin was added to the treatment regimen. Although a surgical approach has been emphasized in patients with peripheral vein suppurative thrombophlebitis, anticoagulation therapy may be a useful alternative in the treatment of patients with central vein infection.

Major venous thrombosis in patients with indwelling venous access catheters

Two patients with Hickman catheters that were used for long-term venous access developed major venous thrombosis, one with superior vena caval and the other with subclavian vein thrombosis. This represented an incidence of 9% of all Hickman catheters that were inserted over two years in The St George Hospital. Staphylococcus epidermidis was cultured from blood that was sampled through the Hickman catheter in both patients; the organism was also cultured from the tip of the removed catheter in one patient. Transverse thoracic computerized tomographic scanning diagnosed the presence and the site of thrombosis as well as excluding the presence of a mediastinal tumour that was causing extrinsic compression. The catheter had to be removed in one patient; in the other patient, heparinization without removal resulted in the resolution of symptoms.

Central venous access with occlusive superior central venous thrombosis

Thrombotic occlusion of the entire superior central venous system is a rare complication of central venous catheterization. Three patients are presented with complete occlusion of the superior vena cava secondary to prolonged central venous catheterization. Thrombotic occlusion of the superior vena cava precludes central venous access by conventional techniques. Thoracotomy with direct catheterization of the right atrium and inferior vena cava cannulation represent alternative approaches but may be associated with significant morbidity. The present report describes a unique combined angiographic/operative technique designed to obtain central venous access with low morbidity in patients with occlusive thrombosis of the superior central venous system.

Long term central venous access catheters: review of 134 catheters inserted in 100 patients

The first 100 patients at Westmead Centre who received long term central venous access catheters were reviewed. The indication for insertion in 77% of the patients was administration of chemotherapy, 15% had insertion for parenteral nutrition and 8% for blood product administration or anti-microbial therapy. Catheter manipulations were carried out under strict aseptic conditions by a limited group of nursing staff. Of the catheters, 73.1% functioned satisfactorily and were removed electively or were functioning at death or time of review. The main reason for removal was suspected infection, but this was proven in only 4.5% although strongly suspected in another 5.2%. The infection rate was 13 episodes per 13 987 catheter days. The duration of function of catheters was analysed by the life table method, demonstrating a 50% catheter survival rate of 300 days.

Infection control during parenteral nutrition therapy

Parenteral nutrition therapy can achieve an anabolic state in patients who are unable to maintain normal nitrogen balance; however, it may be associated with infectious complications. Infections may be related to contamination of the cannula and the cannula wound, of the infusate, or of other parts of the parenteral nutrition system. A variety of microorganisms has been associated with these infections. The exact mechanisms that initiate cannula-related infection are poorly understood. Susceptibility of the host, the method and site of cannula insertion, colonization of parenteral nutrition cannulas, use of parenteral nutrition systems for multiple purposes, cannula material, and other factors may all play some role. Controlling infections depend on many factors, including quality control processes to ensure sterility of parenteral nutrition solutions, attention to aseptic technique during cannula insertion, procedures to prevent in-use contamination, proper care of the cannula insertion site, and proper management of other parts of the parenteral nutrition system. In addition, infectious complications appear to be reduced by an organized team that follows infection control protocols. Many facets of parenteral nutrition therapy are based on data from uncontrolled clinical investigations. Well-designed, controlled clinical trials may provide data that will further minimize the risks associated with parenteral nutrition therapy.

Left innominate vein stenosis as a late complication of central vein catheterization

A patient was seen for acute exercise-induced left superior limb swelling. Phlebography disclosed left innominate vein stenosis and the lack of subclavian vein thrombosis. Ten months earlier, the patient underwent repeated and prolonged central vein catheterization procedures. No other cause of central vein stenosis was evidenced. Emphasis is placed on the symptomatic presenting event, the very late discovery, and the site of stenosis.

Nutritional therapy in advanced cancer. Setting realistic goals

Cancer cachexia is a complex syndrome resulting from metabolic disturbances, mechanical obstacles, and behavioral alterations. Assessments of the potential benefits of nutritional support for an individual patient must reflect the cancer stage and prognosis, the patient's expressed wishes, and the impact of treatment on the family unit. Enteral or parenteral alimentation may preserve body mass during aggressive, potentially curative therapy of early cancer. Palliation may be provided for the more advanced patient whose major problem is not being able to eat. In terminal illness, feeding may no longer be therapeutic--it may briefly prolong life with considerable morbidity and expense. At each stage, decisions should be based on realistic assessments of possible gains and losses to the patient's life and overall well-being.

Central venous access for long-term haemodialysis

Long-term central venous catheterization has been used as the sole method of vascular access in nine chronic dialysis patients with severe access difficulties. The catheters were inserted into the right atrium via external or internal jugular veins by a simple operative technique and have remained in situ for 1-33 months. Although three catheters required replacement for incorrect positioning (two patients) and catheter-associated thrombosis (one patient) no patient failed with the technique. Catheter-related complications were infrequent. The study demonstrates that it is possible to undertake adequate and safe haemodialysis through a permanently indwelling central venous catheter in patients in whom conventional methods of vascular access, and other modes of renal replacement therapy, have failed repeatedly.

The delivery of nutritional support. A potpourri of new devices and methods

With continued interest and increasing awareness of nutritional support to patients, both hospitalized and at home, many new developments in the field of devices and methods of delivering nutritional support have occurred. The indications, methods of use, and the associated complications related to feeding via nasogastric tube, tube esophagostomy, gastrostomy, and jejunostomy in the light of new devices and methods are outlined. The authors' experience shows that postoperative enteral feeding is a reliable and efficient method of providing supportive nutrition, provided the appropriate patients are selected. Home enteral nutritional support via gastrostomy allows stable cancer patients to maintain their nutritional status and enjoy life independent of the hospital setting for an extended period of time. When feeding via the gastrointestinal tract is neither feasible nor desirable, for both short-term and long-term nutritional support, access to the central venous system becomes necessary because peripheral vein feeding has limited cost-effectiveness. Delivery of nutrients into the superior vena cava by long antecubital catheters has been advocated, and the use of Hickman/Broviac catheters, instead of conventional subclavian catheters, is becoming an increasingly common practice. Experience with the use of arteriovenous fistulae and the Infuse-A-Port (Infusaid Corp.) are reviewed; the method used for declotting infected and thrombosed catheters is outlined. Current trends in the use of three-liter bags containing a fat emulsion with glucose and amino acids are mentioned.

Mechanical complications from insertion of subclavian venous feeding catheters: comparison of de novo percutaneous venipuncture to change of catheter over guidewire

Since a percutaneous catheter insertion into the subclavian vein can be tedious, time consuming, and risky, we have compared the morbidity of 137 de novo subclavian catheter insertions to that of 93 reinsertions over guidewire. Mechanical complications were significantly higher (p less than 0.03) in those with catheter insertions (8.8%) than in those with the guidewire insertions (2.2%). These included pneumothorax (4), arterial puncture (4), catheter-size bleed (3), and hemothorax (1) in the catheter insertion group and local bleeding (1) and hydrothorax (1) in the guidewire insertion group. The difference in complications between methods is probably inherent in the techniques. Operator experience was not a factor: 55% of the physicians in each group had previously done less than 26 subclavian venous catheterizations. Preliminary analysis indicates that the infection rate, as determined by semiquantitative, cultures, is the same in each group. When considering the equal potential for infection, we conclude that change over a guidewire is an acceptable alternative to contralateral de novo percutaneous subclavian venipuncture for feeding catheter insertion. In view of fewer mechanical complications and greater ease of insertion, change of subclavian feeding catheters by guidewire is probably the method of choice.