Diagnosis and treatment of cannula-related intravenous sepsis in burn patients

Septic Pulmonary Emboli From Peripheral Suppurative Thrombophlebitis: A Case Report and Literature Review

BACKGROUND:

We report the case of a 90-year old woman who presented with septic pulmonary emboli due to suppurative thrombophlebitis at an old peripheral intravenous site.

METHODS:

After unsuccessful treatment with antibiotics, the patient was taken to the operating room for excision and drainage of the purulent superficial vein.

RESULTS:

We review the literature and discuss the presentation, risk factors, treatment options, and complications of this often-overlooked disease entity.

CONCLUSIONS:

Suppurative thrombophlebitis is a rare but morbid disease that requires a high level of clinical suspicion to diagnose.

Staphylococcus epidermidis Bacteremia Associated With Vascular Catheters: An Important Cause of Febrile Morbidity in Hospitalized Patients

Seventeen episodes of persistent Staphylococcus epidermidis bacteremia (one to nine days) occurred in 16 patients with vascular catheters during a 26-month period. Cases were statistically more likely to have a longer hospitalization (54 v 7.6 days, p < .0005), longer duration of antibiotic therapy (22 v 2.5 days, p = .002), presence of a central venous pressure (CVP) catheter (14 v 2, p < 3 × 10-8), and presence of an arterial catheter (4 v 1, p = 0.037) than randomly selected hospitalized patients matched for age, sex, and date of admission. However, when cases were compared with similarly matched non-bacteremic patients having CVP catheters, these characteristics were not significantly different in the two groups. Furthermore, exposure to total parenteral nutrition (TPN) and duration of TPN were not significantly different between cases and controls. Hence, the presence of a CVP catheter appeared to be the major risk factor for 5. epidermidis bacteremia. In 16 episodes, patients had temperature > 38.6°C without another identifiable cause, and the average white cell count for the case group was 19,400/mm. Seven patients also had diaphoresis, confusion, hypotension, or oliguria. Temperatures returned to normal in 13 within 24 hours after catheter removal, and all patients were afebrile and symptom-free within 72 hours. Thus, vascular catheter-associated S. epidermidis bacteremia was an important case of febrile morbidity in these patients.

Burn wound infections

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.

Burn wound infections

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.

Damage limitation in burn surgery

Burn injury differs from other types of trauma in the apparent lack of urgency for treatment. We argue that in order to limit physiological damage and the development of multi-organ failure, management of the burn wound must be immediate and aggressive. Supportive fluid treatment should be judicious in order to prevent excessive oedema causing wound extension. Some potential strategies utilising oral fluid resuscitation are discussed, and potential pharmacological interventions. When associated with other trauma, major burn injury has a detrimental effect on morbidity and mortality, and surgical management of both aspects of a patient's injuries are altered.

Cannula related suppurative thrombophlebitis in the burned patient

Suppurative thrombophlebitis is a well recognised and potentially fatal complication of intravenous cannulation in burns patients. We report a case of an Afro-Caribbean patient with noninsulin-dependent diabetes who developed signs of systemic sepsis two weeks after a 14% total body surface area flame burn. Despite an initial paucity of clinical signs at the cannulation site, exploratory venotomy revealed frank suppuration within the long saphenous vein from the ankle to the groin. This was treated successfully by total excision of the vein and its tributaries and delayed wound closure. Following this, a retrospective analysis of the measured clinical parameters and blood tests revealed no obvious, missed pointers to the impending sepsis other than a dramatic increase in the overall daily insulin requirement. This had doubled over a 48-h period, preceding the clinical diagnosis by three days. The relevant literature and guidelines for management are reviewed.

Long-term outcome of continuous 24-hour deferoxamine infusion via indwelling intravenous catheters in high-risk β-thalassemia

The optimal regimen of intravenous deferoxamine for iron overload in high-risk homozygous β-thalassemia is unknown because only short-term follow-up has been described in small patient groups. We report the outcome over a 16-year period of a continuous 24-hour deferoxamine regimen, with dose adjustment for serum ferritin, delivered via 25 indwelling intravenous lines for 17 patients. Treatment indications were cardiac arrhythmias, left ventricular dysfunction, gross iron overload, and intolerability of subcutaneous deferoxamine. Cardiac arrhythmias were reversed in 6 of 6 patients, and the left ventricular ejection fraction improved in 7 of 9 patients from a mean (± SEM) of 36 ± 2% to 49 ± 3% (P = .002, n = 9). The serum ferritin fell in a biphasic manner from a pretherapy mean of 6281 ± 562 μg/L to 3736 ± 466 μg/L (P = .001), falling rapidly and proportionally to the pretreatment ferritin (r2 = 0.99) for values &gt;3000 μg/L but falling less rapidly below this value (at 133 ± 22 μg/L/mo). The principal catheter-related complications were infection and thromboembolism (1.15 and 0.48 per 1000 catheter days, respectively), rates similar to other patient groups. Only one case of reversible deferoxamine toxicity was observed (retinal) when the therapeutic index was briefly exceeded. An actuarial survival of 61% at 13 years with no treatment-related mortality provides evidence of the value of this protocol.

Femoral venous access is safe in burned children: an analysis of 224 catheters

OBJECTIVE

To document the incidence of septic and mechanical complications associated with femoral venous catheters in a subgroup of patients thought to be at particularly high risk of both: young children with large burns.

DESIGN

An analysis of data collected prospectively on all femoral venous catheters placed during a 4-year period at a regional pediatric burn facility.

RESULTS

There were 224 femoral catheters placed in 86 children with an average age of 5.3 +/- 5.1 years and an average burn size of 38% +/- 23%. Catheters were left in place for a mean duration of 5.7 days. Catheter-related sepsis occurred with 4.9% of the catheters, and mechanical complications occurred in 3.5% of the patients. There was no statistically significant association between the risk of catheter sepsis and the placement of catheters through burned versus unburned skin. Similarly, the risk of sepsis was equivalent between lines placed over a guide wire and those placed of a new site.

CONCLUSION

Femoral venous catheters are safe in burned children and are associated with a low incidence of infectious and mechanical complications.

Femoral catheters increase risk of infection in total parenteral nutrition patients

Central venous access for the administration of total parenteral nutrition is usually achieved via the subclavian or internal jugular veins. Although a high incidence of complications has been reported with the use of femoral catheters for central venous access, this route has been used when traditional central venous access is contraindicated. We retrospectively reviewed 171 patients who received total parenteral nutrition via a central venous triple-lumen catheter and compared the rates of infections in femoral vs nonfemoral access. A literature review was performed to identify associated complications of and appropriate indications for femoral catheter use. In the 171 patients studied, 355 triple-lumen catheters were placed; these included 331 nonfemoral catheters and 24 femoral catheters. Femoral catheters were placed in nine patients. Femoral catheters had a greater incidence of positive tips (42% vs 6.9%, p < .001) and related bacteremia (16.7% vs 1.8%, p = .002) than did nonfemoral catheters. The organisms most commonly isolated from the blood and catheter tips of both catheter access sites were methicillin-resistant Staphylococcus epidermidis and Candida. The use of femoral catheters for central venous access for total parenteral nutrition administration results in an increased risk of infectious complications.

Prospective comparison of two management strategies of central venous catheters in burn patients

OBJECTIVE

Central venous catheters (CVCs) are associated with sepsis in burn patients. This study was undertaken to compare two strategies of CVC management in patients with major burn injuries.

DESIGN

Forty-two burn patients with major burn injuries were randomly assigned to undergo site change every 48 hours of the CVC or to undergo wire guide exchange of the CVC every 48 hours at the same site.

MATERIALS AND METHODS

Catheter insertion site, distance from the burn wound, cultures of catheter tips, and blood cultures were obtained from all patients in a prospective manner.

MEASUREMENTS AND MAIN RESULTS

There was no difference in the incidence of CVC sepsis between the two groups studied. CVCs inserted less than 5 cm from the burn wound developed bacterial contamination at an earlier time than CVCs inserted more than 5 cm from the burn wound.

CONCLUSIONS

There was no advantage to changing the CVC insertion site every 48 hours. Changing the CVC using the wire guide technique did not prevent, nor predict, CVC bacterial contamination.

Central venous catheter sepsis with weekly catheter change in paediatric burn patients: an analysis of 221 catheters

To document the risk of catheter sepsis associated with central venous catheter changes every 7 days in paediatric burn patients, and analysis of data collected prospectively on 234 such catheters was performed. During an 18-month period there were 301 acutely burned children admitted to a regional paediatric burn facility of whom 53, with an average burn size of 42 per cent TBSA, required 234 central venous catheters. A central venous catheter management protocol was followed which included catheter changes every 7 days. If insertion sites were clean and uninflamed, catheters were replaced by guidewire and the original catheter tip was semiquantitatively cultured. Catheters were replaced to a new site if insertion sites appeared inflamed or catheter tips grew 15 or more colony forming units. Overall, 3.2 per cent (10.9 per cent by Centers for Disease Control definition) of central venous catheters were associated with sepsis. When catheters were replaced by guidewire from one to three times, catheter sites were used for a mean of 15.6 days without an increased rate of line sepsis. There was no difference in sepsis rates between catheters placed at a new site or replaced by guidewire. There were no deaths attributed to catheter-related sepsis. We conclude that a protocol allowing for catheter change to a new site, or replacement by guidewire, every 7 days was associated with a low risk of catheter sepsis in paediatric burn patients.

Serious complications of vascular catheter-related Staphylococcus aureus bacteremia in cancer patients

Over the period 1986 to 1989, 53 cancer patients were identified with catheter-related Staphylococcus aureus bacteremia at the University of Texas M.D. Anderson Cancer Center. Septic thrombosis was diagnosed in 12 (23%) patients and was suspected in another 3 (6%). Of the 12 patients, five developed deep-seated infections (septic emboli, endocarditis, meningitis, abscess), compared with 2 of the 38 other patients with no septic thrombosis (p < 0.01). Fever persisted for more than three days after antibiotic initiation in 52% of the patients with complications (septic thrombosis and/or deep-seated infections), compared with 19% of those without complications (p < 0.02). Of the three patients with complications who were treated for 14 days with intravenous antistaphylococcal antibiotics, two relapsed; in contrast, all of the nine patients with complications who were treated for more than 14 days (mean 4 weeks) were cured, and none relapsed (p < 0.05). Of the nine patients with complications who were treated with a long course of therapy, only one required surgery. The possibility of septic thrombosis and/or deep-seated infections should be considered in all cancer patients with catheter-related Staphylococcus aureus bacteremia, and if present, the condition should be treated with appropriate intravenous antibiotics for at least four weeks.

The changing epidemiology of infection in burn patients

Topical chemotherapy, prompt excision, and timely closure of the burn wound have significantly reduced the occurrence of invasive burn wound infection and its related mortality. Since wound protection is imperfect and invasive wound infection may still occur in patients with massive burns in whom wound closure is delayed, scheduled wound surveillance and biopsy monitoring are necessary to assess the microbial status of the burn wound and identify wound infections caused by resistant bacteria or non-bacterial opportunists at a stage when therapeutic intervention can control the process. As a reflection of the systemic immunosuppressive effects of burn injury, infection remains the most common cause of morbidity and mortality even though the occurrence of wound infections has been significantly decreased. Pneumonia is the most frequent infection occurring in burn patients today but the improvements in patient management, wound care, and infection control have made bronchopneumonia the most common form of this infection and gram-positive organisms the most common causative agents. The organisms causing bacteremia that exert a species specific effect on the mortality related to extent of burn injury and patient age have changed in concert with changes in wound flora. Infection control procedures, including scheduled surveillance cultures, utilization of cohort patient care methodology, strict enforcement of patient and staff hygiene, and patient monitoring have been effective in eliminating endemic resistant microbial strains, preventing the establishment of newly introduced resistant organisms, diagnosing infection in a timely fashion, instituting antibiotic and other necessary therapy in a prompt manner, and documenting the effectiveness of present day burn patient care and the improved survival of burn patients.

Duplex scanning of central vascular access sites in burn patients

Seventy-one burned patients requiring intensive care unit management underwent 570 central venous and 167 femoral arterial catheterizations. These patients were surveyed by repeated physical examinations and duplex scans for vascular-related complications. Catheter sites were rotated every 3 days. No arterial thrombi or occlusions were noted. Fourteen patients (19.6%) had 19 positive venous duplex scans. Five patients (7%) had symptomatic deep venous thrombosis (DVT) and nine (12.6%) had asymptomatic DVT. Mean number of venous cannulations before a positive scan was 4.3 (range 1 to 17). All five symptomatic patients had DVT that originated in the lower extremities. No patient had clinical evidence of a pulmonary embolus, or limb morbidity resulting from the DVT. Follow-up duplex scans in the five asymptomatic and three symptomatic patients showed complete resolution in each case. This study demonstrates the high incidence and natural history of central DVT in a group of critically ill burn patients.

Improvement in catheter sepsis rate in burned children

Routine frequent central venous catheter (CVC) changes in burned patients (either change in insertion site or change over guidewires) has been advocated to decrease catheter-related sepsis. The need for this management has not been verified for children with burns. We reviewed our pediatric burn population with regard to CVC sepsis rate and individual CVC longevity to confirm this traditional policy. From 1978 to 1988, 70 children admitted to the Children's Hospital of Oklahoma Burn Unit required central venous access. Patients in whom CVCs were changed frequently (FC), (n = 10; no. of CVC, 46) were compared with those in whom CVCs were changed only for mechanical complications or sepsis (NFC), (n = 60; no. of CVC, 74). There were 10 septic CVCs in each group. The difference in mean length of individual CVC use between FC and NFC was significant (4.6 v 17.7 days; P less than .01). The difference in the number of septic CVCs per total number of catheter days in each group was highly significant (FC: 10 CVC/212 d. = 0.05; NFC: 10 CVC/1,112 d = 0.009; P less than .001). This study demonstrates a significant decrease in catheter-related sepsis when CVCs are not changed on a routine frequent basis.

Suppurative thrombophlebitis of the superior vena cava

A 22-year-old woman, a neurosurgical comatose patient developed suppurative thrombophlebitis of the superior vena cava due to Klebsiella pneumoniae, as a complication of catheterisation for parenteral nutrition. The diagnosis was established by gallium scan, computed tomography and digital vascular imaging. Conservative treatment with antibiotics and heparin resulted in the emergence of a resistant mutant of the causative agent. The infection could only be eradicated after surgical thrombectomy.

Morbidity and mortality of an endemic pathogen: methicillin-resistant Staphylococcus aureus

Over an 8-year period, two epidemics of methicillin-resistant Staphylococcus aureus (MRSA) occurred in a burn unit. Sources of sepsis were the burn wound and lung. Fourteen percent of the patients colonized with MRSA became bacteremic. The mean postburn day of bacteremia was 19 and the mortality rate was 5 percent. MRSA was introduced to the burn unit when a patient was transferred from another unit, on readmission of a previously infected patient, or heavy burn census when MRSA was epidemic in the hospital. Although the morbidity rate associated with MRSA infections was high, the mortality rate was low. Gram-negative sepsis has continued to be more lethal.

Central venous catheter infections

When used wisely, central venous catheters are capable of providing vital circulatory access in any patient with a remarkably low risk of infection or major complication. Tunneled silicone catheters are the route of choice for long-term or outpatient use, particularly for oncology or TPN patients; insertion of such a catheter should occur early in the hospitalization of a newly diagnosed patient on chemotherapy. The greatest experience has accrued with the cuffed silicone catheters (for example, Broviac), but the totally implantable devices (for instance, Port-a-cath) may become the device of choice in pediatric outpatients. For infants, small, percutaneously inserted noncuffed silicone catheters appear to offer the greatest safety. Among acute care patients, percutaneous plastic central venous catheters fulfill a vital role but represent an important source of infection. Scrupulous technique, the minimizing of manipulation, and a readiness to replace the catheter at any suggestion of trouble are important to achieving the best results. Within a given design, it is generally best to use the smallest diameter catheter capable of performing the desired tasks. However, on the basis of currently available data, there need be no hesitation to use a multilumen catheter if the care of the patient demands multiple access ports. The various silicone catheters can usually be left in place while infection is treated, although fungal and certain other infections are more likely to require catheter removal. Percutaneous plastic catheters should be removed or changed over a wire if infection is suspected; if tip culture of the removed catheter is positive, and the catheter was replaced over a wire, then the replacement catheter should be promptly removed.

Defatting catheter insertion sites in total parenteral nutrition is of no value as an infection control measure. Controlled clinical trial

Defatting the skin with acetone or ether is widely used in the regimen for disinfection of insertion sites of central venous catheters in total parenteral nutrition. The fatty acids secreted by normal skin play an important role in regulation of the cutaneous microbial ecosystem, and it can be questioned whether application of a solvent might paradoxically promote colonization by pathogenic microorganisms. The clinical value of defatting catheter insertion sites was prospectively studied in a controlled, randomized trial: 100 subclavian catheters inserted for total parenteral nutrition were given identical site care except that with one half of the catheters, the site was defatted with acetone prior to catheter insertion and as part of the every-other-day site care regimen. Cutaneous colonization was found in only 130 (24.5 percent) of 531 site cultures in both groups, but was strongly predictive of concordant colonization of the catheter (relative risk, 22.1, p less than 0.001) and catheter-related septicemia (all four cases). No significant differences were observed between the two groups in cutaneous colonization of sites (22.7 percent and 27.0 percent), in colonization of catheters on removal (four catheters [8 percent] in each group) or in catheter-related septicemia (two catheters [4 percent] in each group). However, pain or inflammation of the insertion site was twice as frequent in the acetone group (80 percent versus 35 percent, p less than 0.001). Defatting with acetone as part of the regimen for cutaneous disinfection does not improve microbial removal or reduce the incidence of catheter-related infection, but increases cutaneous inflammation and patient discomfort.

Nutritional considerations for the burned patient

The metabolic response to injury is one of marked catabolic hormonal predominance resulting in hypermetabolism and protein wasting. Energy expenditure increases with increasing severity of injury, but reaches a maximum of twice resting energy expenditure when 50 per cent TBSA is burned. We agree with the nutritional recommendations of the group at the Boston Shriner's Burn Institute and the Massachusetts General Hospital. These include providing calories at twice the resting energy expenditure, as predicted by the Harris-Benedict equations, for patients with greater than 30 per cent BSAB; protein is provided at 2.5 gm per kg per day based on ideal body weight. It is important to recognize that these are optimal goals, but their attainment must be governed by safety considerations for the patient. It is probably safe to supplement intake with a multivitamin and vitamin C, as well as zinc, but our understanding of micronutrient therapy for stressed patients is rudimentary.

Suppurative thrombophlebitis: correlation between pathogen and underlying disease

We identified 29 episodes of suppurative thrombophlebitis in 27 patients admitted to a large general hospital between May 1980 and May 1984. In 25 patients, the intravenous cannulae had been in place for more than 3 days. Streptococcus faecalis, Pseudomonas aeruginosa or one of the Enterobacteriaceae were implicated in 14 patients. All these patients had recently undergone abdominal surgery or had a major intra-abdominal inflammatory process at the time they developed thrombophlebitis. The remaining 13 patients were infected with Staphylococcus aureus, other gram-positive cocci or Candida species. Only two of these had an active abdominal process at the time of their infection (chi 2 = 16.08, P less than 0.001). There is an apparent association between phlebitis caused by enteric organisms and active intra-abdominal pathology. There were two deaths related to delayed or deferred surgery. Suppurative thrombophlebitis is a lethal, preventable nosocomial infection that requires urgent surgical intervention.

Improved burn center survival of patients with toxic epidermal necrolysis managed without corticosteroids

Fifteen consecutive patients with toxic epidermal necrolysis or the Stevens-Johnson syndrome managed without corticosteroids after transfer to the burn center (group 2) are compared to a previous consecutive group of 15 who received high doses of these drugs (group 1). Group 2 had a 66% survival, which was a significant improvement compared to the 33% survival in group 1 (p = 0.057). In group 1, mortality was associated with loss of more than 50% of the body surface area skin. In group 2, mortality was related to advanced age and associated diseases. Age, extent of skin loss, progression of skin loss after burn center admission, incidence of abnormal liver function tests, and the incidence of septic complications were not significantly different in the two groups (p greater than 0.10). The incidence of detected esophageal slough was similar in both groups. Nonsteroid (group 2) management was associated with a decreased incidence of ulceration of gastrointestinal columnar epithelium, Candida sepsis, and an increased survival after septic complications. The combined experience of these 30 patients suggests that corticosteroids are contraindicated in the burn center management of toxic epidermal necrolysis and the Stevens-Johnson syndrome.

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.

Blood hemoglobin: a possible predictor of central venous catheter-related thrombosis in parenteral nutrition

The biochemical records of 43 patients given nutritional support via a central venous catheter (CVC) for between 7 and 111 days (mean 28 days) without anticoagulant therapy were reviewed. On completion of the parenteral nutrition, phlebography was performed via the CVC. Patients developing CVC-related thrombosis (22/43, 51%) were assigned to group I and those without this phlebographic finding (21/43, 49%) to group II. The blood (B-) hemoglobin concentration before catheterization was higher in group I than in group II, the values being 121 +/- 16 (mean +/- SD) and 106 +/- 13 g/liter, respectively. An initial B-hemoglobin level above 127 g/liter showed a high positive accuracy of prediction for CVC-related thrombosis and on this basis 89% (8/9) of the patients were correctly assigned to group I, whereas an initial B-hemoglobin level below 111 g/liter showed a lower accuracy of prediction for a normal phlebographic status and on this basis 71% (12/17) of the patients were correctly assigned to group II. The specificity of the test criteria--B-hemoglobin greater than 127 and less than 111 g/liter--was high, with values of 95% (20/21) and 77% (17/22), respectively, whereas the sensitivity was low; only 36% (8/22) of group I had an initial B-hemoglobin above 127 g/liter and in group II 57% (12/21) recorded a value below 111 g/liter. It is concluded that if a patient has an initial B-hemoglobin concentration of more than 127 g/liter there is a high risk that CVC-related thrombosis will develop during parenteral nutrition lasting 1 wk or more.

Subclavian venous thrombosis due to indwelling catheters: a prospective study on 52 patients

Clinical occurrence of subclavian venous thrombosis due to indwelling catheters is rare, but there is some evidence that subclinical thrombosis frequently occurs. It is purpose of this study to report the results of a prospective investigation in patients with subclavian vein catheters. Fifty-two patients admitted to the Istituto Nazionale Tumori of Milan and candidate to infraclavicular percutaneous catheterization of the subclavian vein were evaluated. There were 26 polyvinyl chloride and 26 rubber silicone catheters, which were correctly positioned in the superior vena cava-atrium. Average duration of the intravenous stay was 12.8 days. Asymptomatic thrombosis was venographically demonstrated in 46.1% of the polyvinyl chloride catheters and in 11.5% of the silicone ones (p = 0.005). The average age of catheters with or without thrombosis was 10.8 and 13.8 days, respectively. Addition of heparin to the infusate (1 U/ml) did not reduce the thrombosis rate in polyvinyl chloride or in silicone catheters, but risk of thrombosis was significantly higher (p = 0.03) in polyvinyl chloride catheters without heparin in comparison to the silicone ones. Osmolarity of the infusional fluid, manipulation during the cannulation, colonization of the catheter tip, and duration of the intravenous stay of the catheter apparently did not influence the rate of thrombosis. Since the natural history of the thrombotic subclavian veins is not known, some caution must be paid to repeat the percutaneous cannulation of the same vein and the change the catheter over a guidewire.

Prevention and treatment of central venous catheter sepsis by exchange via a guidewire. A prospective controlled trial

A new approach for preventing and treating sepsis due to central venous catheter (CVC) has been devised at the Istituto Nazionale Tumori of Milan. A prospective protocol has been developed that includes the weekly exchange of the CVC via a guidewire as well as its exchange when a CVC-related sepsis is suspected. Growth of microorganisms on the tip of the CVC is defined as contamination if peripheral blood culture is negative and as sepsis if it is positive for the same microorganism. Colonization simply means growth of microorganism independently of the results of peripheral blood culture. Two hundred seven CVCs (64 polyvinyl chloride and 143 rubber silicone) were evaluated in 62 patients, for a total of 170 exchanges. The incidence of colonization and sepsis was 33.8% and 4.8%, respectively, a rate which is not significantly different from the values found in 81 historical controls (30.8% and 11.1%). However, it is noteworthy that the sepsis rate was reduced strongly during the first month of observation (0% vs. 11.9%; p = 0.01), whereas in the second month, it was similar in both groups (15% vs. 7.1%). Moreover, it should be noted that three-fourths of the colonized CVCs became negative after the first exchange, and virtually all were negative at the fourth exchange. All of the episodes of sepsis resolved spontaneously with the CVC exchange. The study, therefore, concludes that this procedure: 1) is without risk for CVC cross contamination, 2) is effective in the treatment of contaminated CVCs and of septic patients without any interruption of total parenteral nutrition, and 3) can reduce the incidence of CVC sepsis during the first month of total parenteral nutrition. One must be cautious about the possible onset of pulmonary embolism in patients with subclavian venous thrombosis, since a transient pulmonary embolism occurred in one of the patients. With the use of silastic CVCs, which are less thrombogenic than polyvinyl ones, the rate of pulmonary embolism due to blind exchange (without previous venography) is estimated to be 0.1% to 0.2%.