Evaluation of infectious complications of the implantable venous access system in a general oncologic population

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1 Evaluation of infectious complications of the implantable venous access system in a general oncologic population Lilu Chang, RN, MSN Jir-Shiong Tsai, MD, FACP Shin-Ju Huang, RN Chiang-Ching Shih, MD Taipei, Taiwan, Republic of China Objectives: This study was conducted to evaluate the infectious morbidity associated with 2 common types of implantable port systems used in a cancer center in Taiwan. Methods: This study is retrospective and descriptive. Five hundred seventy-two patients who received implantable ports at the cancer center between January 1994 and December 1998 were included. The following 4 types of catheter-related infections were defined in this study: bloodstream, pocket, exit-site, and tunnel. Semiquantitative methods (rolling plate) were used for cultures of removed catheters. Results: The average duration for ports after placement in patients was 358 days (range, days), and the median duration was 242 days. The port-related infection rate was 5.6% in 586 ports and 0.15 per 1000 device-days. Our data indicate that when a port is in use, more frequent dressing changes of the needle exit site (every 3 days vs every 7 days) appear to have no significant impact on the catheter-related infection rate (5.2% vs 7.3%, P =.3). Our observation also indicates that if the catheter is used for total parenteral nutrition (TPN), the patient has a significantly increased chance of developing an infection from the Candida species (71% vs 8%, P =.005). Furthermore, the catheters associated with infections caused by the Candida species had a shorter catheter life (median, 44 days). Conclusions: Infection is the most common complication of venous port system use among cancer patients. According to our data, it is safe and cost-effective to change exit-site needles and transparent dressings every 7 days. It is clearly demonstrated by our study that patients with ports used for the administration of TPN had a significantly greater chance of developing infection from the Candida species. Further investigation is needed to compare the relative advantages of using ports versus other devices for the administration of TPN in cancer patients. (Am J Infect Control 2003;31:34-9.) The need for intravenous access devices for the administration of cancer therapy has increased proportionately with the increasing number of patients diagnosed with cancer. To have a reliable venous access for the delivery of therapeutic agents was particularly problematic until long-term venous devices From the Infection Control Committee, Koo-Foundation Sun,Yat-Sen Cancer Center. Reprint requests: Lilu Chang, RN, MSN, 125 Lih-Der Road, Pei-Tou District,Taipei,Taiwan, Republic of China. Copyright 2003 by the Association for Professionals in Infection Control and Epidemiology, Inc /2003/$ doi: /mic became available. 1,2 Most chemotherapy agents irritate the veins and may cause phlebitis and eventual obliteration of peripheral veins. If extravasation of vesicant agents occurs, the surrounding tissue may have a serious reaction, which may eventually lead to tissue damage and infection. The development of the implantable port has provided for a more reliable and convenient access for administering various therapeutic agents in cancer patients. 2-9 A further advantage of the implantable port is that it requires minimum care and maintenance when it is not in use. However, complications from the use of implantable ports do occur, with one of the most common being infection Numerous studies have focused on evaluating the short-term complications of the devices. However, the long-term complications, particularly 34

2 Chang et al February the infectious morbidity, have not been carefully evaluated. To prevent infections is essential in caring for cancer patients because most of them are immunocompromised during the disease course. Infections that develop during the course of treatment not only may result in longer hospital stays but also may increase health care costs. This study evaluates the infectious morbidity associated with 2 common types of implantable port systems used in our institution an established oncology center in Taiwan. PATIENTS AND METHODS This study is retrospective and descriptive. Five hundred seventy-two patients who received implantable ports for the management of cancer at the Sun Yat-Sen Cancer Center between January 1994 and December 1998 were included. Patients who were not treated or followed-up by our center were excluded. The χ 2 test was used to compare the difference between groups. The following 2 types of ports were used: (1) the Port-a-Cath (Pharmacia Implantable Access Systems, St. Paul, Minn), which is a stainless titanium portal with an internal volume of 0.5 ml that connects to a radiopaque silicone rubber catheter, and (2) the MRI port (Bard Access Systems, Salt Lake City, Utah), which is a plastic rubber portal with an internal volume of 0.5 ml and a silicone septum that is connected to a silicone Groshong catheter (a closed-system catheter with a 3-way valve that allows infusion and blood aspiration while reducing blood reflux and clotting). When ports were used, nurses adhered to our standard protocol for exit-site care, the transparent dressing of needle-insertion site, and administration set change. If ports were used at home, the home care nurse adhered to the same protocol for care and maintenance of the ports. Data, therefore, were stratified into the 2 following groups according to different protocols developed during the study period for comparing infection rate: the first group included patients whose ports were removed between January 1994 and July 1995 and whose access needles and intravenous administration sets were changed every 3 days, and the second group included patients whose ports were removed between August 1995 and December 1998 and whose access needles and intravenous administration sets were changed every 7 days. The site of needle insertion was dressed with transparent dressing (Tegaderm; 3M Health Care, St. Paul, Minn) in both groups. The dressing was changed when the needles and intravenous administration sets were replaced or whenever dressings were wet or soiled. The unused ports were flushed with 5 ml of normal saline containing 250 units of heparin (50 units/1 ml normal saline) every 4 weeks. The following 4 types of catheter-related infections were defined in our study according to Centers for Disease Control and Prevention guidelines 15 : 1. Bloodstream infection (BSI): isolation of the same organism from a blood culture drawn from the portal and from the peripheral vein of a patient with accompanying clinical symptoms of BSI and no other apparent source of infection. 2. Pocket infection: induration, erythema, and tenderness of the skin over the site of port placement or purulent exudate in the subcutaneous pocket containing the port. 3. Exit-site infection: erythema, tenderness, induration within 2 cm of port surface needle access site, or purulence at the port surface needle access site. 4. Tunnel infection: erythema, tenderness, and induration in the tissues overlying the catheter and more than 2 cm from the exit site. All catheter-related infections in our study were categorized according to these definitions. However, few infections were not proved by cultures but were a physician s clinical diagnosis. We categorized infections as BSI if patients had clinical signs of BSI and had no other sources of infections and the infectious signs subsided after removing the catheter. In our center, the indication to remove an infectious port is determined by the type, severity, and organisms of infections. Infected ports were removed immediately in the following circumstances: (1) when infections were recognized as pocket infections, tunnel infections, or exit-site infections with a large quantity of pus; (2) when infections were associated with septic emboli or infectious endocarditis; and (3) when infections were identified from blood cultures of port reservoirs as being from the Staphylococcus, Candida, Pseudomonas, Bacillus, and the Corynebacterium jeikeium. In our study, few of the catheters were removed on the basis of only the decision of the primary physicians. All catheters removed were sent to the laboratory for cultures, and semiquantitative methods (rolling plate) were used for those cultures. RESULTS Between January 1994 and December 1998, a total of 586 ports were placed in 572 patients. Among

3 36 Vol. 31 No. 1 Chang et al Table 1. Microbiologic isolation Total BSI Organisms No. (%) No. (%) Fig 1. Disease distribution. these patients, 12 received 2 ports, and 1 of them received 3 insertions. As shown in Fig 1, the disease most frequently encountered among patients in this study was breast cancer (195/572), followed by colorectal cancer (148/572) and other gastrointestinal tract cancer (64/572). Two hundred thirty-nine Port-a-Cath ports (Pharmacia) and 347 MRI ports (Bard) were used in patients during the study period. All of these ports were single lumen and placed in the operating room. The placement of a port was indicated in either of 2 following circumstances: when patients had poor venous access or when they needed long-term continuous intravenous infusion therapy. The average duration for a port to remain in place was 358 days (range, days), and the median duration was 242 days. The total accrued sum of device-days for the 586 ports studied was 209,694 days. In total, 205 ports (35%) remained in place until the patients died, 277 ports (47.3%) were still in use at the time the data were reviewed, and 50 ports (8.5%) were removed electively because treatment was completed during the study period. In addition, 54 ports (9.2%) were removed because of complications. Of these, 29 catheters (53.7%) were removed because of infectious complications, and 25 (46.3%) were removed because of noninfectious complications. The median interval for removing catheters because of complications was 122 days (range, days). Catheter occlusions that necessitated removal occurred in 18 of the 586 ports inserted (3%) and was the major cause of catheter removal among the noninfectious complications. However, infectious complications were the major reason for premature removal of catheters and were also the major complications associated with catheters in our study. NFGNB* 9 (.30) 6 (.20) Pseudomonas aeruginosa 4 (.13) 3 (.10) Acinetobacter baumannii 2 (.07) 1 (.03) Stenotrophomonas maltophilia 2 (.07) 1 (.03) Burkholderia cepacia 1 (.03) 1 (.03) Yeast 7 (.23) 6 (.20) Candida albicans 6 (.20) 5 (.17) Other Candida species 1 (.03) 1 (.03) Skin flora 11 (.37) 5 (.17) CoNS 6 (.2) 4 (.13) Corynebacteria 1 (.03) 0 (0) Staphylococcus aureus 3 (.10) 0 (0) Bacillus species 1 (.03) 1 (.03) Entero bactericeae 3 (.10) 2 (.07) Klebsiella pneumoniae 1 (.03) 1 (.03) Escherichia coli 1 (.03) 1 (.03) Serratia marcescens 1 (.03) 0 (0) NFGNB, Nonglucose fermentative gram-negative bacilli; CoNS, Coagulase-negative Staphylococcus. Twenty-nine of 33 catheter-related infections (94%) resulted in the removal of the catheters. Of these 33 infections, the majority were BSI (n = 21, 66%). The incidence of exit-site infections (n = 6, 19%) and pocket infections (n = 5, 15%) was lower. The estimated number of total infections per 1000 device-days was Overall, approximately 50% of infections occurred within 100 days after implantation of the catheter. The median interval from the time of port insertion to the time when device-related infection was detected was 80 days (range, days). Microbiologic data of port-related infections are summarized in Table 1. The most common micro-organism isolated from port cultures was that of the Candida species (n = 7), followed by the coagulase-negative Staphylococcus species (n = 6) and Pseudomonas aeruginosa (n = 4). Among 21 catheter-related BSI episodes, the most common micro-organism isolated from the patients also was of the Candida species (n = 6), followed by the coagulase-negative Staphylococcus species (n = 4) and P aeruginosa (n = 3). In a total of 7 infections resulting from the Candida species, 71% (n = 5) were associated with total parenteral nutrition (TPN) (Table 2). Although a higher infection rate (7.7% vs 4.5%) was noted in male groups, it was not statistically significant (P =.1). Patients with nonsolid tumors had higher infection rates compared with patients with solid tumors (10.3% vs 5.4%); however, the differ-

4 Chang et al February Table 2. Comparisons of yeast infection with and without TPN ence was not statistically significant (P =.2) and may be due to the small number of nonsolid tumors in our patient population. There was a similar infection rate between Pharmacia and Bard ports (5.4% vs 5.8%, P = 1.0). Younger patients in our study (< 40 years) appeared more likely to develop catheterrelated infection (9.9% vs 4.2%, P =.009) (Table 3). Incidences of infection were higher in the group for whom access needles and administration sets were changed every 3 days compared with the group for whom they were changed every 7 days (7.3% vs 5.2%, P =.3) (Table 4). All patients with catheter-related infections in our study responded to catheter removal and (or) antibiotic therapy. Most of the catheters (94%) were removed promptly once catheter-related infections were suspected. DISCUSSION Total With TPN Without TPN n n (%) n (%) Candida infection 7 5 (71%) 2 (29%) Bacterial infection 26 2 (8%) 24 (92%) P =.005; χ 2. Table 3. Comparisons of patients with and without infection With Without Total infection infection P Variables n n (%) n (%) value Sex Man (7.7%) 191 (92.3%).1 Woman (4.5%) 362 (95.5%) Tumor Solid (5.4%) 527 (94.6%).2 Nonsolid 29 3 (10.3%) 26 (89.7%) Port type Pharmacia (5.4%) 226 (94.6%) 1.0 Bard (5.8%) 327 (94.2%) Age (9.9%) 137 (90.1%).009 > (4.2%) 416 (95.8%) χ 2. Table 4. Infection comparison between different frequencies of port access needle change (every 3 days vs every week) Total With TPN Without TPN n n (%) n (%) Every 3 days (7.3%) 114 (92.7%) Every week (5.2%) 439 (94.8%) P =.3; χ 2 test. Infections are the most common and feared complications of long-term indwelling catheters. It was previously reported that implanted subcutaneous venous ports have a lower risk of infections and can be maintained in-site longer than other venous devices. 5-9 The infection rate of indwelling venous catheters has been reported to range between 2.4% to 16%. 1,2,4,5,8,9,11,12 It also was reported that the average infection rate in cancer patients with longterm central venous catheters is 1 to 2 per 1000 device-days. 13 The overall infection rate observed in our hospital was similar to that reported by other investigators (5.6% vs 2.4%-16%). However, among cancer patients, the infection rate is lower in our institution (0.12 vs 1-2 per 1000 device-days). The 4 major risk factors associated with catheter-related infections were identified as host factors, catheter type, duration of use, and catheter maintenance and management. 13 Although we are located in a hot and humid tropical and semitropical area, the catheter-related infection rate is similar to or even better than that of patients who live in drier geographic locations. We believe that our standards of care and maintenance are chiefly responsible for the low infection rate. In our study, the younger patients (< 40 years) were more prone to having catheter-related infections and shorter duration of the device in place. Our results are similar to Memorial Sloan-Kettering Cancer Center s report in Since this study was limited to retrospective investigation, the cause of higher infection rate in these younger patients is unclear. The gender of the patients and pathologic findings of the tumor did not relate to the incidence of infection. However, it has been reported that male patients and patients with nonsolid tumors are more likely to have port-related infections. 10 Our study has shown that the infection rate among patients with closed-end Groshong catheters (MRI port; Bard Access System) and those with open-ended catheters (Port-a-Cath; Pharmacia Implantable Access System) is similar. Thus far, there is no safety standard or consensus in practice indicating how long the access needles can be left in-site. Hempsey et al 14 compared the rate of infection between 2 groups of patients whose access

5 38 Vol. 31 No. 1 Chang et al needles were changed with different frequency (1 vs 2 weeks). Although the result of their study was inconclusive, the authors reported that leaving needles in situ for 2 weeks was just as safe as leaving them there for only 1 week. There is also no CDC recommendation for the frequency of dressings change on central catheter sites. 15 Our study suggested that when ports are in use, less frequent changes of access needles and dressings (every 7 days vs every 3 days) result in lower incidence of infection (5.2% vs 7.3%, P =.3). It is reasonable to suggest that in cancer patients with implantable ports, it is probably acceptable and safe to change access needles and dressings every 7 days. In our study, most port infections occurred after 1 month of implantation. Furthermore, 67% of the infectious organisms isolated were identified as skin flora and nonglucose fermentative gram-negative bacilli. These figures imply that rigorous care of the site of port insertion is the most important factor in preventing catheter-related infections. Establishing a centralized standard of care and maintenance has been shown to reduce catheter-related infection rates significantly. 16 Although all the care at our institution was not centralized, it was standardized. Maintenance of sterility and patency of the ports in our cancer patients was performed by well-trained nurses in accordance with standard protocols. We believe that diligent nursing care contributed to the low catheter-related infection rate among our cancer patients. Staphylococcus, the predominant species found on human skin, are the most common organisms to cause catheter-related infections. 13,16 Infection caused by the Candida species is more commonly isolated from the immunocompromised host. 17 The Staphylococcus and Candida species bind well to host protein and adhere better to silicone catheters. 13 In our study, these pathogens also were commonly isolated from the intravenous devices of patients who developed infections. Five of 7 catheters (71%) used for TPN caused infection from the Candida species. However, only 2 of 26 catheters (8%) not used for TPN were associated with Candida infections (P =.005). It should be noted that in patients who developed Candida infections, the median number of days to infection was 44. This interval, which is significantly shorter than that of infections caused by other organisms (44 days vs 126 days), indicates that ports used for TPN are prone to developing fungal infections. Several similar observations of a high incidence of fungal infections among patients receiving TPN indicate that the TPN solution may play a role in fungal infection Certain types of catheters may further increase the incidence of fungal infection when they are used for TPN. Clinicians, therefore, carefully need to select the appropriate catheter for TPN. The results of our study suggest that the intravenous line for TPN should be used with special caution and imply that the port may not be a good choice for delivering TPN in cancer patients. CONCLUSIONS Our observations are similar to those reported by the other investigators: infection is the most common complication in the use of venous port systems among cancer patients. Some catheter-related infections are difficult to prevent due to the general condition of the patient, some types of treatments, and the nature of invasive procedures. However, the infection rate can be significantly lowered by appropriate preventive strategies and by good patient care performed by a well-trained nursing staff. For debilitated and immunocompromised cancer patients, diligent aseptic care is even more important in reducing catheter-related infections. According to our data, it is safe and cost-effective to change exit-site needles and transparent dressings every 7 days. Because most of the infectious organisms are commonly colonized on the skin and in the fluids, it is most important to sterilize and maintain cleanliness of the exit-site area. Finally, our study clearly demonstrates that ports used for the administration of TPN results in the patient having a significantly greater chance of developing infection from the Candida species. The advantages of using ports for chemotherapy in cancer patients have been well documented; however, further investigation is needed to compare the relative advantages of using ports versus other devices for the administration of TPN in cancer patients. We are grateful to Cosi Long for her help and support in preparing this manuscript. References 1. Lambert ME, Chadwick GA, McMahon A, Scarffe JH. Experience with the Port-a-Cath. Hematol Oncol 1988;6: May GS, Davis C. Percutaneous catheters and totally implantable access systems: a review of reported infection rates. J Intravenous Nurs 1988;11(2): Strum B, McDermed J, Korn A, Joseph C. Improved methods for venous access: the Port-a-Cath, a totally implanted catheter system. J Clin Oncol 1986;4(4): Carde P, Cosset-Delaigue MF, Laplanche A, Chareau I. Classical external indwelling central venous catheter versus totally

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