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Venous Access Preoperative, Operative, and Postoperative DilemmasJeffrey A. Lowell, MD,* and Albert Bothe, Jr, MDt *Staff, Department of General Surgery, Lahey Clinic Medical Center, Burlington, Massachusetts; and Clinical Instructor of Surgery, Harvard Medical School, Boston, Massachusetts tAssociate Chairman of Surgery, Department of Surgery, New England Deaconess Hospital; and Associate Professor of Surgery, Harvard Medical School, Boston, Massachusetts Surgical Clinics of North America 1991;71(6):1231-1246. Aubaniac5 in 1952 described his 10-year experience with the use of subclavian vein catheters for the rapid infusion of resuscitation fluids in military casualties. This was the first reported use of the central venous catheter.5, 14 Use of the central venous catheter did not begin to gain widespread popularity until the article by Wilson et al115 in 1962 on the advantages of measurement of central venous pressure. It was landmark papers by Dudrick and associates36, 37 on the development of total parenteral nutrition in 1968 that led to the rapid development and wide use of central venous catheters. Broviac et al24 and Hickman et al56 described the use of the tunneled Silastic catheter. Bothe et al6 and Neiderhuber et al83 subsequently reported on the development of a totally implantable central venous access system. It has been estimated that in 1986 approximately 500,000 patients received total parenteral nutrition and that 2.75 million central venous catheters were used.2 100 Today, central venous access is used not only for total parenteral nutrition but also for long-term administration of intravenous antibiotics, delivery of chemotherapeutic agents, parenteral fluid therapy in patients without peripheral venous access or in patients who require rapid volume resuscitation, measurement of hemodynamic pressures and delivery of cardiovascular pressor agents, placement of temporary or permanent pacemakers, access for temporary or permanent hemodialysis, and shunting of various body fluids, such as ventriculoatrial shunts for hydrocephalus or peritoneoatrial shunts for ascites. The use of central venous catheters continues to increase as the number of patients being treated for solid tumors and leukemias as well as for acquired immunodeficiency syndrome increases.110 Morbidity associated with the use of central venous catheters includes pneumothorax; chylothorax, hemothorax, or hydrothorax; air embolism; catheter embolism; infection; injury to great vessels; thrombosis; malposition; osteomyelitis of the clavicle; injury to the brachial plexus; and injury to the phrenic nerve.14 15 17 20 21 23 27 30 40 41 44 55 63 65 72 80 84 85 88 92 97 100 102 103 108 110 Today, surgeons are faced with the responsibility of placing central venous catheters not only in patients who are sick enough to justify the risks associated with placement and ongoing use of central venous catheters but also in patients who have survived catastrophic illnesses or in patients whose chronic diseases may continue to require central venous access. This latter group of patients typically has alterations in normal venous anatomy, diminished ability to combat infections, or abnormal coagulation. These patients are also at highest risk for, but can least well tolerate complications from, insertion and subsequent use of central venous catheters. [NOTE: The portion of this article on infections will be covered in a future issue of Meditheses.] The role for tunneling the central venous catheter placed for short-term use is uncertain.17 66 Tunneling the catheter is an option, however, when the proximity of the exit site of the central venous catheter to an area of burn, infection, tracheostomy, or other source of potential infection makes the risk of contamination high. In patients with a central venous catheter placed into the internal jugular vein, inability to maintain an occlusive dressing, considerable discomfort, and torticollis may also be indications for creation of a subcutaneous tunnel.9 The main problem in the treatment of patients with catheter-related sepsis is that the diagnosis is best made retrospectively. Clinical criteria for the diagnosis of catheter-related sepsis and empiric removal of catheters are associated with an 85% false-positive rate.l7 19 87 97 Removal of a catheter in a patient whose care mandates use of the central venous catheter will subject the patient to the risks associated with reinsertion. To wait for the results of diagnostic bacteriologic tests that are more specific for catheter-related sepsis carries the risks inherent with delay of treatment. Treatment. In the patient with a nontunneled central venous catheter placed for short-term use, clinically suspected catheter-related sepsis warrants exchange of the catheter over a guide wire as a method of bacteriologic sampling. This technique has been shown to be both safe and effective.l7 l9 90 The treatment of presumed or actual catheter-related sepsis in patients with tunneled Silastic catheters or venous infusion ports is more complicated. The administration of antibiotics through the central venous catheter has been effective in the treatment of patients with catheter-related sepsis with permanent Silastic catheters in place.l7 28 99 Infection with coagulase-negative staphylococcus is the most common cause of catheter-related sepsis, and this infection is usually treated by intracatheter administration of vancomycin (Vancocin) for a course of 7 to 14 days.28 Polymicrobial infections and infections with more virulent bacteria or fungi rarely respond to this method of treatment and typically require removal of the catheter with systemic antimicrobial therapy and replacement of the catheter in a new site when the risk associated with secondary seeding has passed.8 l7 28 In the high-risk patient with limited or no remaining central venous access, the surgeon should consider the exchange of the tunneled catheter or venous infusion port during continued antibiotic treatment....73 Tunnel infections respond to antibiotic treatment alone in only 25% of patients and usually require removal of the catheter. A much greater likelihood of successful treatment for infections at the exit site is with combined local treatment and systemic antibiotic therapy that permit salvage of the central venous catheter in about 70% of patients.8 28 Patients with catheter-related sepsis whose infection does not respond promptly to antibiotic therapy may have some degree of unrecognized catheter thrombosis. One series99 described a treatment protocol in which a contrast study was obtained through the central venous catheter in patients whose infection failed to respond to antibiotic therapy. When catheter thrombosis was identified, the addition of thrombolytic therapy through the catheter was successful.
Catheter- Related ThrombosisDefinition. Catheter-related thrombosis was first described in 1971 by McDonough and Altemeier.8l Early reports6 8l focused on the development of fatal intracardiac thrombi as extensions of the central vein thrombosis in children with central venous catheters placed for parenteral nutrition. Subsequently, physicians described many sequelae associated with catheter-related thrombosis, including pulmonary embolism, chronic upper-extremity edema, pain, pseudotumor cerebri, and, of perhaps more importance, loss of remaining central venous access. 3 39 8l 62 68 97 l05 Incidence. The incidence of catheter-related thrombosis ranges from 3% to 70%18 39 42 58 61 65 69 71 85 87 93 95 105 111 113 This large range reflects the difficulty in accurately defining and diagnosing catheter-related thrombosis. Catheter-related thrombosis may refer to the fibrin sheath that surrounds the central venous catheter, thrombosis in the catheter lumen, or central vein thrombosis. Reported incidences of catheter-related thrombosis may vary greatly based on whether the diagnosis is made on clinical grounds alone or on the results of various diagnostic tests. Investigations may also be performed prospectively or only when initiated based on symptoms. The sensitivity of the diagnostic tests also varies greatly. In order of increasing sensitivity, studies used to diagnose catheter-related thrombosis include venous plethysmography, duplex scanning, radionuclide studies, magnetic resonance contrast imaging, and venography ( Table 3 ). Duplex scanning and radionuclide scanning are associated with higher rates of false-negative results because extensive venous collateral flow may mask true central vein occlusion.58 89 Radionuclide studies carry the added benefit of baseline lung perfusion scanning, however, which is occasionally helpful in the further evaluation of patients with catheter-related thrombosis.80 l2 Conventional or digital subtraction contrast studies can be performed either through the catheter or through a peripheral vein. Studies performed through the catheter or through a peripheral vein. Studies performed through the catheter may miss partial vein thrombosis at the site of entry of the central catheter into the vein. Thrombogenicity is rarely controlled for in studies that investigate the incidence of catheter-related thrombosis. In decreasing order of thrombogenicity, catheters may be composed of polyvinyl chloride, polyethylene, polyurethane, and Silastic. Perhaps the most important variable is the underlying pathologic condition that prompts the use of the central venous catheter. Differing degrees of hypercoagulability or hypocoagulability can be expected among patients with leukemia, cirrhosis, malnutrition, chronic renal failure, or osteomyelitis. Clinical signs and symptoms of catheter-related thrombosis include ipsilateral swelling of the neck and arm, venous distention, and nonspecific pain in the neck and anterior chest wall.85 89 The range of clinically detectable catheter-related thrombosis is 0 to 4.8%25,78,87,97,105,111 ,112 A fibrin sleeve that envelops the catheter will develop in virtually all central venous catheters in place for more than 1 week.l 39 62 65 69 78 l05 The importance of the fibrin sleeve in relation to the development of central vein thrombosis (partial or complete), catheter lumen thrombosis, or catheter-related sepsis is not well understood. Some degree of catheter occlusion by thrombosis is also common, occurring in more than 90% of all patients with central venous catheters in place for any appreciable duration.l23
Several prospective series ll 25 43 58 have demonstrated partial or complete central vein thrombosis by venography in 28% to 54% of patients with central venous catheters. A small number of patients with positive results on venography have symptoms referable to the thrombus.
Etiology. The various causes of catheter-related thrombosis can be distilled to the etiologic triad that Virchow outlined first, namely, local trauma, stasis, and altered coagulability. The difficulty of insertion; the duration of use; and the size, flexibility, and composition of the central venous catheter might all be considered important factors that contribute to the local traumatic effects on the central vein.18 42 58 69 85 ll4 The composition of the infusate may also be an important component of ongoing trauma to the vein, such as chemotherapeutic drugs that are particularly sclerosing and solutions with extremes of pH or osmolarity.42 47 58 85 ll4 As previously discussed, a frequent association between catheter-related thrombosis and catheter-related sepsis exists, although a casual relationship has yet to be proved.60 64 l08 ll4 Venous stasis may predispose to catheter-related thrombosis. Many patients with central venous catheters are ill and frequently are confined to bed. Some patients who require cardiovascular monitoring have some degree of hypotension, dehydration, or heart failure. In patients with a head and neck or pulmonary tumor, external compression of the great veins may develop 38 39 42 60 85 Alteration in normal coagulability is common in patients with malignant processes, septicemia, or inflammatory conditions. This alteration may in part be caused by low levels of serum antithrombin III, a potent thrombin inhibitor and heparin cofactor.l0 ll 42 64 69 7l 85 In patients prospectively studied by the sensitive von Kaulla assay of antithrombin III activity, catheter-related thrombosis developed in 52% of patients with accelerated assays versus 13.6% in patients with normal results on assay.10 A partial thromboplastin time that is shorter than the control value also appears to be an independent risk factor for thrombosis.ll Treatment. Treatment of patients with catheter-related thrombosis includes several combinations of thrombolytic therapy, anticoagulation, and removal of the catheter. The treatment should be guided by the severity of the symptoms and the need for ongoing use of the central venous catheter. Low-dose local administration of thrombolytic agents to treat thrombotic occlusion of catheter lumens is highly successful. Streptokinase, urokinase, and tissue plasminogen activator have been used, with catheter patency restored in more than 95% of attempts.23 48 50 5l 59 6l 96 l04 l07 The treatment of partial or complete central vein thrombosis ranges from simple removal of the catheter to full systemic anticoagulation, depending on the severity of symptoms. 23 35 78 85 In patients with long-term needs for central venous catheterization or limited central venous access, we recommend systemic heparinization followed by a period of therapeutic sodium warfarin (Coumadin) therapy while the catheter is left in place (Table 4). Local or systemic thrombolytic therapy in patients with catheter-related thrombosis, especially patients with superior vena cava syndrome, has had variable results. 35 57 6l 63 67 78 85 95 l04
Prevention. Preventive measures to lower the incidence of central vein thrombosis have focused primarily on decreasing the effects of local trauma on the great veins and altering the relative hypercoagulability seen in many patients who require placement of a central venous catheter. Catheters should be Silastic whenever the expected duration of therapy is long. Catheter-associated infections should be minimized by excellent care of the catheter by experienced specialized nurses. Early identification and treatment of infections should also reduce the incidence of catheter-related thrombosis. 90 Efforts to decrease the effects of hypercoagulability (as measured by depressed levels of antithrombin III and an acceleration of the partial prothromboplastin time) have centered on two methods. The first is the use of heparin in continuous parenteral nutrition solutions (3000 U/L) administered through central venous catheters. In one prospective study, 67 the rate of catheter-related thrombosis as demonstrated by radionuclide venography decreased from 32% to 8% in the group receiving continuous heparin infusion. This result has been confirmed by other investigators. 22 60 The second method to reduce coagulability involves the use of low-dose warfarin in patients with Silastic central venous catheters. This has been shown ll l2 to reduce appreciably the likelihood of the development of catheter-related thrombosis in high-risk patients without prolonging the prothrombin time or partial prothromboplastin time. In one series, l2 patients received 1.0 mg of warfarin daily, beginning 3 days before placement of the Silastic central venous catheter. Patients were prospectively studied using digital subtraction venography. At 90 days, catheter-related thrombosis developed in 50% of patients in the control group, most of whom were symptomatic, whereas catheter-related thrombosis developed in only 11% of patients who received low-dose warfarin. ll 12
SummaryThe past two decades have seen a tremendous increase in the use of central venous catheters and its associated complications. The increased sophistication that physicians now have with regard to nutritional and metabolic needs has escalated the use of central venous catheters. As the acquired immunodeficiency syndrome epidemic grows, so too will the number of patients with infections and metabolic complications, many of whom will have conditions severe enough to benefit from the use of central venous catheters to deliver antimicrobial drugs and other supportive intravenous therapy. Our ability to sustain patients with short-bowel syndrome also relies critically on central venous access. Likewise, treatment of patients with leukemias and certain solid tumors frequently requires placement of these catheters. Central venous catheters are essential for bone marrow transplantation. Efforts to minimize the risks associated with placement of a central venous catheter by more frequent use of catheter exchange rather than another venipuncture should be encouraged when possible. Techniques to prevent arrhythmia during overinsertion of guide wires are also important. Vigilant searches for, and prompt treatment of, catheter-related sepsis and central vein thrombosis are critical. Better prophylaxis against the development of catheter-related sepsis and catheter-related thrombosis is also needed. Further prospective investigations should be performed, however, to define precisely cost-effective methods of detection and duration of therapy for patients with both catheter-related sepsis and catheter-related thrombosis. Further advances in the technology and management of catheters need to continue to meet these ongoing challenges. Reprinted with permission from the Surgical Clinics of North America 1991;71(6): 1231-1246.
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