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An evaluation of two methods for chronic central venous access device placement
An Evaluation of Two Methods for Chronic Central Venous Access Device Placement Honnie Bermas, MD, Roxie M. Albrecht, MD, Diana Vogt, MD, Albuquerque, New Mexico
BACKGROUND: Chronic venous access devices (CVADs), placed for phlebotomy and the administration of medications and nutrition, require fluoroscopy to confirm correct catheter position. Long-term central venous catheters placed using an electromagnetic catheter locating system (EMCLS) could result in decreased radiation exposure and decreased cost without compromising accuracy of position. METHODS: Charts of patients who underwent placement of CVADs at University of New Mexico (UNM) Hospital or UNM Cancer Center were reviewed. Inclusion criteria included age >20 years and placement of a central CVAD utilizing fluoroscopy (group 1) or the EMCLS (group 2). Radiation exposure, complications, cost, and accuracy of placement were determined for each technique. RESULTS: Between June 1996 and June 1998, 196 patients underwent placement of CVADs. Complete data sets were available for 46 patients in each group. There were no statistically significant differences in age, gender, complications, or operating room times (P ⴝ 0.26). Fluoroscopy and EMCLS were equally accurate for the correct placement of the tip of the line (P ⴝ 0.12). Mean patient radiation exposure was EMCLS, 30 mRem, and fluoroscopy, 771 mRem. EMCLS significantly decreased cost (P ⴝ 0.025) when compared with fluoroscopic assisted catheter placement. CONCLUSIONS: The use of EMCLS for CVAD placement reduces radiation exposure and cost without compromising the accuracy of placement when compared with standard fluoroscopic-assisted placement. Am J Surg. 1999;178:560 – 563. © 1999 by Excerpta Medica, Inc.
N
umerous patients require chronic venous access devices (CVADs) for the administration of medications or nutrition or for the purpose of phlebotomy. Since these catheters are designed to remain in situ for several months to years, appropriate positioning of the
From the Department of Surgery, University of New Mexico, Albuquerque, New Mexico. Requests for reprints should be addressed to Roxie M. Albrecht, MD, Department of Surgery, University of New Mexico, 2211 Lomas Boulevard, NE, 2ACC, Albuquerque, New Mexico 87131. Presented at the 51st Annual Meeting of the Southwestern Surgical Congress, Coronado, California, April 18 –21, 1999.
560
© 1999 by Excerpta Medica, Inc. All rights reserved.
catheter tip in the central venous system is essential. Most of these central venous catheters are placed in the operating room or a designated minor procedure room in order to adhere to an aseptic environment and strict sterile technique. Intraoperative fluoroscopy is often used to guide the catheter into the correct position. The disadvantages of utilizing fluoroscopy include radiation exposure and the cost of the x-ray equipment and personnel in the operating room (OR). Additionally, the necessary lead shielding devices are cumbersome for the surgeon and OR personnel. Recently, electromagnetic catheter locator systems have been introduced as alternatives to fluoroscopy.1–7 These systems consist of a hand-held device that generates highfrequency magnetic fields and sensors placed in the tips of the guidewires and catheters. The tip of the CVAD may be positioned correctly with the use of this hand-held instrument, which makes an audible noise and flashes a light when it is held directly above the guidewire tip or the catheter stylet. Several authors have reported on the efficacy of these catheter locator systems for the insertion of peripherally implanted CVADs.1– 6 In 1997, Frank et al7 studied an EMCLS for the placement of standard chest wall subcutaneous CVAD. By using this system, cost and radiation exposure were reduced. Ninety-eight percent of the catheters were positioned correctly using the electromagnetic catheter locating device. We sought to determine whether the EMCLS could be used to accurately place CVADs while reducing complications, radiation exposure and cost. We tested our hypothesis by comparing catheters placed using EMCLS to those placed under fluoroscopic guidance.
MATERIALS AND METHODS Patient Selection and Demographics Charts of patients who underwent placement of CVADs at the UNM Hospital (UNMH) or UNM Cancer Center (UNMCC) between June 1996 and June 1998 were reviewed. Inclusion criteria included age ⬎20 years, utilization of fluoroscopy (group 1) or the EMCLS (group 2), and placement of a subcutaneous central venous port, Hickman (C.R. Bard, Inc. Salt Lake City, Utah), or Groshong (C.R. Bard, Inc. Salt Lake City, Utah) catheter. The EMCLS used for this study was the CathTrack Locator, Sensor Guidewire and Sensor Stylet (Catheter Locator System; Bard, Salt Lake City, Utah). Patients were excluded from the study if their charts did not contain complete data sets (age, gender, indication for the line, catheter type used, approach, OR time, fluoroscopy time, chest radiography results to confirm placement). 0002-9610/99/$–see front matter PII S0002-9610(99)00241-X
TWO METHODS FOR PLACING CHRONIC CENTRAL VENOUS ACCESS DEVICE/BERMAS ET AL
Implantation Procedure and Determination of Accuracy All CVADs were placed in an aseptic environment in the minor surgical OR or main OR at UNMH or in the ambulatory minor surgical suite in the UNMCC. The minor surgical OR rooms were equipped with standard conscious sedation monitoring equipment. The personnel in the minor surgical OR consisted of a nurse to monitor and administer sedation and an operating room technician. In the main OR an anesthesiologist or nurse anesthetist administered sedation and/or an anesthetic agent. In all areas, maximal sterile barrier technique was practiced. This included wide povidone-iodine skin preparation, sterile instruments, sterile gown, sterile gloves, mask, hat, and wide draping of the insertion site. The insertion side and approach, subclavian or internal jugular, were selected by the surgeon placing the catheter. Correct catheter tip positioning in the operating room was guided by the use of fluoroscopy or the EMCLS. All patients underwent postprocedure upright chest radiography (CXR) to verify correct positioning of the catheter and to identify insertionrelated complications. Accuracy of placement was determined by a radiologist’s interpretation of a postprocedure CXR. Correct catheter tip placement was defined as the location of the catheter tip within the superior vena cava (SVC) no less than 2 cm from the junction of the superior vena cava and right atrium (RA). If the tip of the catheter was in the RA, at the RA/SVC junction, or in a vessel other than the SVC, it was considered to be malpositioned. Determination of Complications, Cost, and Radiation Exposure Medical records were reviewed for intraoperative and postoperative complications. Cost analysis data was calculated from (1) the purchase cost of the catheters, (2) the purchase cost of the EMCLS instrument averaged over the number of EMCLS catheters included in the study, and (3) purchased hospital services. The purchased hospital services used for cost analysis included (1) the time used in the operating room, (2) the time used with the fluoroscopic equipment/personnel in the operating room, and (3) the standard postprocedure CXR. The professional fees of the surgeon, anesthesiologist, and radiologist were not evaluated. Radiation exposure was based on a CXR resulting in 30 mRem of exposure and fluoroscopy resulting in 16 mRem/sec.8 Statistical analysis was performed by the Anderson-Darling normality test, chi-square test, Fischer’s exact test, and the two-sample t test.
RESULTS One hundred and ninety-six patients underwent placement of CVAD by fluoroscopy or EMCLS between June 1996 and June 1998. Complete data sets were available for 46 patients in each group. The remaining patients had incomplete data sets and were excluded from the study. Patient Characteristics There were no statistically significant differences in age (P ⫽ 0.26; Table I), gender (P ⫽ 0.83; Table I), or site of insertion (P ⫽ 0.86; Table II). Indications for the catheters were statistically different with 100% of EMCLS
TABLE I Patient Demographics, Indications for Central Venous Access Device Placement
Age (mean ⫾ SEM) Gender Females Males Indications Intravenous medications Parenteral nutrition
Group 1 (n ⴝ 46)
Group 2 (n ⴝ 46)
48.5 ⫾ 2.7
52.2 ⫾ 1.8
30 16
29 17
34 12
46 0
P Value 0.26 0.83
⬍0.001*
* Fischer’s exact P value.
TABLE II Central Venous Access Device Insertion Sites Site
Group 1 (n)
Group 2 (n)
17 23 5 1
21 20 4 1
Right subclavian Left subclavian Right internal jugular Left internal jugular Fischer’s exact P value ⫽ 0.086.
TABLE III Complications of Central Venous Access Device
Complications Total Infection Pneumothorax Malposition Other
Group 1 (n ⴝ 46)
Group 2 (n ⴝ 46)
Fischer’s Exact P Value
19 7 1 9 2
17 11 1 3 2
0.83 0.43 1 0.12 1
patients (group 2) receiving the line for IV medications versus 74% of fluoroscopy patients (group 1): (P ⬍0.001; Table I). Accuracy of Placement Although not statistically different, there was a trend toward greater accuracy of placement using EMCLS (43 of 46, 94%) versus fluoroscopy (37 of 46, 80%; P ⫽ 0.12). In the EMCLS group, 2 catheters were malpositioned in the right atrium and 1 in the left subclavian vein. In an additional patient in this group, a catheter placed via a right subclavian approach was initially appropriately positioned in the mid-superior vena cava; however, a CXR at 1 month revealed that the catheter had migrated to the right internal jugular vein. In the fluoroscopy group, 6 catheters were malpositioned in the right atrium, 1 in the left subclavian vein, 1 in the internal mammary vein, and 1 in a persistent left superior vena cava (Table III, malposition). Complication Rates Complication rates were not statistically different (P ⫽ 0.83, Table III). Infection was the most common compli-
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TABLE IV Cost Analysis: Equipment and Placement Cost ⴞ SEM
Catheters Total Single Lumen Groshong Double Lumen Groshong Port Hickman
Group 1 (n)
Group 2 (n)
$1335.02 ⫾ 42.49 (46) $1359.46 ⫾ 67.18 (21) $1248.03 ⫾ 49.07 (19) $1735.00 ⫾ 98.04 (4) $1104.80 ⫾ 25.00 (2)
$1188.21 ⫾ 48.36 (46) $1077.62 ⫾ 46.48 (27) $1270.72 ⫾ 68.91 (13) $1590.39 ⫾ 147.99 (6) (0)
P Value* 0.025 0.001 0.791 0.439
* By t test.
cation, seen in 7 patients in group 1 and 11 patients in group 2. Additional complications included pneumothorax (1 patient in each group), arterial puncture (1 in each group), and subclavian vein thrombosis (1 in group 1). Three patients in the group 1 had more than one complication. Cost The calculated cost for each catheter placed via the EMCLS, $1188.21 ⫾ $48.36, was significantly less than catheters placed via fluoroscopy, $1335.02 ⫾ $42.49, (P ⫽ 0.025; Table IV). The purchased OR time was not statistically different with fluoroscopy (group 1) at 54 minutes and EMCLS (group 2) at 59 minutes (P ⫽ 0.30). The purchased radiology services was significantly higher in group 1 compared with group 2 (P ⬍0.001). This difference was due to the use of fluoroscopy personnel/time and a portable postprocedure CXR in group 1 compared with only a standard in-department CXR in group 2. The purchase cost of the single-lumen catheters was the same for both groups, whereas the EMCLS double-lumen catheters and ports had a higher purchase cost than the standard catheters. Radiation Exposure Radiation exposure per catheter using EMCLS was 30 mRem, which was significantly less than the radiation exposure per catheter (771 mRem) using fluoroscopy (P ⬍0.001; 95% confidence interval for mu between 552 mRem to 989 mRem using the Anderson-Darling normality test).
COMMENTS Catheter locator systems have many applications. In 1991, Finney et al2 demonstrated that catheter locator systems could be used accurately and safely at the bedside for the insertion of peripherally implanted CVAD. In 1995, Rubenstein et al3 demonstrated the safety and efficacy of training physician assistants to peripherally implant CVAD using one of these systems. Furthermore, since the hand-held electromagnetic device is portable and relatively inexpensive, it can be purchased by centers without fluoroscopic capabilities for the insertion of either peripheral or central CVADs. Similar to a prior study where the majority of catheters were placed by the right internal jugular,9 we have shown that catheters can be accurately placed from several central 562
venous approaches using the EMCLS. The sensor at the tip of the guidewire or catheter can be identified, even when in abnormal locations. In these situations, the hand-held detection device can be used to accurately reposition the catheter. The use of this system allows the operator to be free of exposure to radiation and the burdensome lead x-ray gowns. Radiation exposure may be significant to surgeons and personnel who are present for multiple catheter placements using fluoroscopy. Direct exposures to levels above 5,000 mRem are considered a risk factor for cancer.8 The exposure to the surgeon and operating room personnel within 1 m of the field is 1/10th of 1% the exposure to the patient.8 Although seemingly insignificant, with repeated cumulative events, radiation exposure can reach concerning levels. Electromagnetic catheter locator systems may eliminate the risk of cumulative radiation exposure to surgeons and OR personnel. Similar to prior studies,7 cost analysis in this study indicated a statistically significant cost reduction in catheters placed via EMCLS versus standard fluoroscopic techniques. Fluoroscopic equipment and personnel are not utilized with the EMCLS, resulting in radiology cost savings. The cost of the EMCLS includes the purchase of the hand-held electromagnetic detector and the EMCLS compatible catheters, which may have a higher cost than standard catheters. This may be the reason why cost reduction did not reach statistical significance in all subgroups. However, the device may be used for multiple catheter placements, allowing the initial purchase cost of the hand-held device to be distributed over many patients. Thus, as more catheters are placed we anticipate cost savings in all subgroups. The favorable results from this study has stimulated our institution to purchase a second EMCLS for use in our main operating area.
CONCLUSION The use of an electromagnetic catheter locator system for CVAD placement significantly reduces radiation exposure and cost without compromising the accuracy of placement or the complication rate when compared with standard fluoroscopic-assisted placement.
REFERENCES 1. Carre MC, Vega JML, Carles J, et al. Central venous brachial catheter (P.A.S. Port TM) and catheter scanning system (CathFinder TM). J Surg Oncol. 1994;55:190 –193.
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2. Finney R, Albrink MH, Hart MB, Rosemurgy AS. A cost effective peripheral venous port system placed at the bedside. J Surg Res. 1992;53:17–19. 3. Rubenstein EB, Fender A, Rolston KV, et al. Vascular access by physician assistants: evaluation of an implantable peripheral port system in cancer patients. J Clin Oncol. 1995;13:1513–1519. 4. Morris P, Buller R, Kendall S, Anderson B. A Peripherally implanted permanent central venous access device. Obstet Gynecol. 1991;78:1138 –1142. 5. Pullyblank AM, Pearce SZ, Tanner AG, et al. Comparison between peripherally implanted ports and externally sited catheters
for long-term venous Access. Ann R Coll Surg England. 1994;76: 33–38. 6. Schuman E, Ragsdale J. Peripheral ports are a new option for central venous access. J Am Coll Surg. 1995;180:456 – 460. 7. Frank JL, Halla B, Garb JL, Reed WP. Fluoroscopy-free placement of standard chest wall subcutaneous chronic venous access devices. Ann Surg Oncol. 1997;4:597– 602. 8. Mettler FA, Upton AC. Medical Effects of Ionizing Radiation. 2nd ed. Philadelphia: WB Saunders; 1995. 9. Starkhammar H, Bengtsson M, Kay DA, Shapiro AR. Central venous catheter placement using electromagnetic position sensing: a clinical evaluation. Biomed Instrument Technol. 1996;30:164 –170.
DISCUSSION
small study size, yet you go on to conclude that the use of electromagnetically guided catheters resulted in a cost reduction. How did you come to this conclusion? Edward Nelson, MD (Salt Lake City, Utah): You said that this technique is as accurate or more accurate than fluoroscopy. The way I’ve always used fluoroscopy, the catheter is either in the right position or I know that it’s not. In other words, the accuracy should be essentially 100%. In your fluoroscopy group, do you use a small amount of dye to document position? I’ve never accepted leaving the OR suite using fluoroscopy guidance unless I knew the catheter position was right, or in a patient who had a central thrombosis or other anatomic problem, I was willing to accept it being not correctly placed.
Ronald A. Squires, MD (Oklahoma City, Oklahoma): This study retrospectively reviews the efficacy and the utility of using an electromagnetic probe to direct the placement of central venous catheters, thereby avoiding the need for fluoroscopy. The data are consistent with several similar articles in the literature, as has been outlined for you. This technology does seem to offer several advantages over traditional imaging techniques in terms of cost, convenience, and safety. Eliminating the need for fluoroscopy could greatly reduce the radiation exposure to our patients as well as to our surgical teams. In addition, intraoperative delays and scheduling conflicts could be potentially avoided when fluoroscopy is required simultaneously in multiple procedural suites. Finally, cost could be reduced not only by the direct elimination of fluoroscopy itself, but also by allowing the access placement to be performed in minor surgical suites not designated for fluoroscopic use. After reviewing the manuscript, I would like to ask the authors the following questions: First, did you identify any patients who failed electromagnetic positioning attempts who subsequently required fluoroscopic guidance? If so, were there any risk factors identified such as numerous previous central lines or central vein thromboses that would suggest the patient needed fluoroscopic assistance from the beginning? Second, the manuscript states that this technique was used for ports, Hickman’s, and Groshong catheters. What size catheters were placed? Although we are all reasonably comfortable inserting small introducers blindly using Seldinger technique, our institution has found it to be safer to insert the larger and quite stiff 12.5-French dilators under direct fluoroscopic visualization. You appear to be using patient retail cost for the calculation of catheters, x-ray, and fluoro time, while using hospital wholesale cost when figuring the expense of the electromagnetic wand. This can create a cost bias against fluoroscopy within your study. Do you charge a patient for the use of the wand within the procedure room? Also, I did not identify any cost difference noted in your study between the catheters with built-in electromagnetic sensor wires and standard catheters. In our institution, electromagnetic catheters are more expensive than their traditional counterparts. Finally, you noted in your paper that the cost difference analysis did not reach statistical significance owing to your
CLOSING Honnie Bermas, MD: To answer whether we had to convert to fluoroscopic placement of any lines, we found that most of the problems were technical. For some reason, our EMCLS device didn’t function correctly. Most of the time the batteries needed to be changed, and we needed to send it back to the manufacturer. We didn’t really run into any other difficulties in terms of needing to convert. We didn’t use any 12.5-French catheters. The largest that we used was an 8. We usually used a single- or a doublelumen catheter. We haven’t used this technique for vast cath or anything larger. There is a cost difference between these catheters and standard catheters, which we did take into account in calculating our cost differential. We found that the cost reduction wasn’t statistically significant, but we feel that since so many more catheters can be placed using this device, the cost of the device can be averaged over the number of catheters. Our feeling is that over time as you inserted more catheters, you would save money in the long run. In terms of the accuracy of the placement, we did find that the fluoroscopy group was outside of the range of the SVC and the RA in a greater proportion of patients, and I can’t explain why that is the case. Regarding the last question, I think physicians feel a little bit more confident with fluoroscopy, since they’re looking right at the catheter, but the learning curve for this machine is quite speedy, and once you learn to use the device over the chest wall, you can gain quite a bit of confidence in your technique.
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BACKGROUND: Chronic venous access devices (CVADs), placed for phlebotomy and the administration of medications and nutrition, require fluoroscopy to confirm correct catheter position. Long-term central venous catheters placed using an electromagnetic catheter locating system (EMCLS) could result in decreased radiation exposure and decreased cost without compromising accuracy of position. METHODS: Charts of patients who underwent placement of CVADs at University of New Mexico (UNM) Hospital or UNM Cancer Center were reviewed. Inclusion criteria included age >20 years and placement of a central CVAD utilizing fluoroscopy (group 1) or the EMCLS (group 2). Radiation exposure, complications, cost, and accuracy of placement were determined for each technique. RESULTS: Between June 1996 and June 1998, 196 patients underwent placement of CVADs. Complete data sets were available for 46 patients in each group. There were no statistically significant differences in age, gender, complications, or operating room times (P ⴝ 0.26). Fluoroscopy and EMCLS were equally accurate for the correct placement of the tip of the line (P ⴝ 0.12). Mean patient radiation exposure was EMCLS, 30 mRem, and fluoroscopy, 771 mRem. EMCLS significantly decreased cost (P ⴝ 0.025) when compared with fluoroscopic assisted catheter placement. CONCLUSIONS: The use of EMCLS for CVAD placement reduces radiation exposure and cost without compromising the accuracy of placement when compared with standard fluoroscopic-assisted placement. Am J Surg. 1999;178:560 – 563. © 1999 by Excerpta Medica, Inc.
N
umerous patients require chronic venous access devices (CVADs) for the administration of medications or nutrition or for the purpose of phlebotomy. Since these catheters are designed to remain in situ for several months to years, appropriate positioning of the
From the Department of Surgery, University of New Mexico, Albuquerque, New Mexico. Requests for reprints should be addressed to Roxie M. Albrecht, MD, Department of Surgery, University of New Mexico, 2211 Lomas Boulevard, NE, 2ACC, Albuquerque, New Mexico 87131. Presented at the 51st Annual Meeting of the Southwestern Surgical Congress, Coronado, California, April 18 –21, 1999.
560
© 1999 by Excerpta Medica, Inc. All rights reserved.
catheter tip in the central venous system is essential. Most of these central venous catheters are placed in the operating room or a designated minor procedure room in order to adhere to an aseptic environment and strict sterile technique. Intraoperative fluoroscopy is often used to guide the catheter into the correct position. The disadvantages of utilizing fluoroscopy include radiation exposure and the cost of the x-ray equipment and personnel in the operating room (OR). Additionally, the necessary lead shielding devices are cumbersome for the surgeon and OR personnel. Recently, electromagnetic catheter locator systems have been introduced as alternatives to fluoroscopy.1–7 These systems consist of a hand-held device that generates highfrequency magnetic fields and sensors placed in the tips of the guidewires and catheters. The tip of the CVAD may be positioned correctly with the use of this hand-held instrument, which makes an audible noise and flashes a light when it is held directly above the guidewire tip or the catheter stylet. Several authors have reported on the efficacy of these catheter locator systems for the insertion of peripherally implanted CVADs.1– 6 In 1997, Frank et al7 studied an EMCLS for the placement of standard chest wall subcutaneous CVAD. By using this system, cost and radiation exposure were reduced. Ninety-eight percent of the catheters were positioned correctly using the electromagnetic catheter locating device. We sought to determine whether the EMCLS could be used to accurately place CVADs while reducing complications, radiation exposure and cost. We tested our hypothesis by comparing catheters placed using EMCLS to those placed under fluoroscopic guidance.
MATERIALS AND METHODS Patient Selection and Demographics Charts of patients who underwent placement of CVADs at the UNM Hospital (UNMH) or UNM Cancer Center (UNMCC) between June 1996 and June 1998 were reviewed. Inclusion criteria included age ⬎20 years, utilization of fluoroscopy (group 1) or the EMCLS (group 2), and placement of a subcutaneous central venous port, Hickman (C.R. Bard, Inc. Salt Lake City, Utah), or Groshong (C.R. Bard, Inc. Salt Lake City, Utah) catheter. The EMCLS used for this study was the CathTrack Locator, Sensor Guidewire and Sensor Stylet (Catheter Locator System; Bard, Salt Lake City, Utah). Patients were excluded from the study if their charts did not contain complete data sets (age, gender, indication for the line, catheter type used, approach, OR time, fluoroscopy time, chest radiography results to confirm placement). 0002-9610/99/$–see front matter PII S0002-9610(99)00241-X
TWO METHODS FOR PLACING CHRONIC CENTRAL VENOUS ACCESS DEVICE/BERMAS ET AL
Implantation Procedure and Determination of Accuracy All CVADs were placed in an aseptic environment in the minor surgical OR or main OR at UNMH or in the ambulatory minor surgical suite in the UNMCC. The minor surgical OR rooms were equipped with standard conscious sedation monitoring equipment. The personnel in the minor surgical OR consisted of a nurse to monitor and administer sedation and an operating room technician. In the main OR an anesthesiologist or nurse anesthetist administered sedation and/or an anesthetic agent. In all areas, maximal sterile barrier technique was practiced. This included wide povidone-iodine skin preparation, sterile instruments, sterile gown, sterile gloves, mask, hat, and wide draping of the insertion site. The insertion side and approach, subclavian or internal jugular, were selected by the surgeon placing the catheter. Correct catheter tip positioning in the operating room was guided by the use of fluoroscopy or the EMCLS. All patients underwent postprocedure upright chest radiography (CXR) to verify correct positioning of the catheter and to identify insertionrelated complications. Accuracy of placement was determined by a radiologist’s interpretation of a postprocedure CXR. Correct catheter tip placement was defined as the location of the catheter tip within the superior vena cava (SVC) no less than 2 cm from the junction of the superior vena cava and right atrium (RA). If the tip of the catheter was in the RA, at the RA/SVC junction, or in a vessel other than the SVC, it was considered to be malpositioned. Determination of Complications, Cost, and Radiation Exposure Medical records were reviewed for intraoperative and postoperative complications. Cost analysis data was calculated from (1) the purchase cost of the catheters, (2) the purchase cost of the EMCLS instrument averaged over the number of EMCLS catheters included in the study, and (3) purchased hospital services. The purchased hospital services used for cost analysis included (1) the time used in the operating room, (2) the time used with the fluoroscopic equipment/personnel in the operating room, and (3) the standard postprocedure CXR. The professional fees of the surgeon, anesthesiologist, and radiologist were not evaluated. Radiation exposure was based on a CXR resulting in 30 mRem of exposure and fluoroscopy resulting in 16 mRem/sec.8 Statistical analysis was performed by the Anderson-Darling normality test, chi-square test, Fischer’s exact test, and the two-sample t test.
RESULTS One hundred and ninety-six patients underwent placement of CVAD by fluoroscopy or EMCLS between June 1996 and June 1998. Complete data sets were available for 46 patients in each group. The remaining patients had incomplete data sets and were excluded from the study. Patient Characteristics There were no statistically significant differences in age (P ⫽ 0.26; Table I), gender (P ⫽ 0.83; Table I), or site of insertion (P ⫽ 0.86; Table II). Indications for the catheters were statistically different with 100% of EMCLS
TABLE I Patient Demographics, Indications for Central Venous Access Device Placement
Age (mean ⫾ SEM) Gender Females Males Indications Intravenous medications Parenteral nutrition
Group 1 (n ⴝ 46)
Group 2 (n ⴝ 46)
48.5 ⫾ 2.7
52.2 ⫾ 1.8
30 16
29 17
34 12
46 0
P Value 0.26 0.83
⬍0.001*
* Fischer’s exact P value.
TABLE II Central Venous Access Device Insertion Sites Site
Group 1 (n)
Group 2 (n)
17 23 5 1
21 20 4 1
Right subclavian Left subclavian Right internal jugular Left internal jugular Fischer’s exact P value ⫽ 0.086.
TABLE III Complications of Central Venous Access Device
Complications Total Infection Pneumothorax Malposition Other
Group 1 (n ⴝ 46)
Group 2 (n ⴝ 46)
Fischer’s Exact P Value
19 7 1 9 2
17 11 1 3 2
0.83 0.43 1 0.12 1
patients (group 2) receiving the line for IV medications versus 74% of fluoroscopy patients (group 1): (P ⬍0.001; Table I). Accuracy of Placement Although not statistically different, there was a trend toward greater accuracy of placement using EMCLS (43 of 46, 94%) versus fluoroscopy (37 of 46, 80%; P ⫽ 0.12). In the EMCLS group, 2 catheters were malpositioned in the right atrium and 1 in the left subclavian vein. In an additional patient in this group, a catheter placed via a right subclavian approach was initially appropriately positioned in the mid-superior vena cava; however, a CXR at 1 month revealed that the catheter had migrated to the right internal jugular vein. In the fluoroscopy group, 6 catheters were malpositioned in the right atrium, 1 in the left subclavian vein, 1 in the internal mammary vein, and 1 in a persistent left superior vena cava (Table III, malposition). Complication Rates Complication rates were not statistically different (P ⫽ 0.83, Table III). Infection was the most common compli-
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TABLE IV Cost Analysis: Equipment and Placement Cost ⴞ SEM
Catheters Total Single Lumen Groshong Double Lumen Groshong Port Hickman
Group 1 (n)
Group 2 (n)
$1335.02 ⫾ 42.49 (46) $1359.46 ⫾ 67.18 (21) $1248.03 ⫾ 49.07 (19) $1735.00 ⫾ 98.04 (4) $1104.80 ⫾ 25.00 (2)
$1188.21 ⫾ 48.36 (46) $1077.62 ⫾ 46.48 (27) $1270.72 ⫾ 68.91 (13) $1590.39 ⫾ 147.99 (6) (0)
P Value* 0.025 0.001 0.791 0.439
* By t test.
cation, seen in 7 patients in group 1 and 11 patients in group 2. Additional complications included pneumothorax (1 patient in each group), arterial puncture (1 in each group), and subclavian vein thrombosis (1 in group 1). Three patients in the group 1 had more than one complication. Cost The calculated cost for each catheter placed via the EMCLS, $1188.21 ⫾ $48.36, was significantly less than catheters placed via fluoroscopy, $1335.02 ⫾ $42.49, (P ⫽ 0.025; Table IV). The purchased OR time was not statistically different with fluoroscopy (group 1) at 54 minutes and EMCLS (group 2) at 59 minutes (P ⫽ 0.30). The purchased radiology services was significantly higher in group 1 compared with group 2 (P ⬍0.001). This difference was due to the use of fluoroscopy personnel/time and a portable postprocedure CXR in group 1 compared with only a standard in-department CXR in group 2. The purchase cost of the single-lumen catheters was the same for both groups, whereas the EMCLS double-lumen catheters and ports had a higher purchase cost than the standard catheters. Radiation Exposure Radiation exposure per catheter using EMCLS was 30 mRem, which was significantly less than the radiation exposure per catheter (771 mRem) using fluoroscopy (P ⬍0.001; 95% confidence interval for mu between 552 mRem to 989 mRem using the Anderson-Darling normality test).
COMMENTS Catheter locator systems have many applications. In 1991, Finney et al2 demonstrated that catheter locator systems could be used accurately and safely at the bedside for the insertion of peripherally implanted CVAD. In 1995, Rubenstein et al3 demonstrated the safety and efficacy of training physician assistants to peripherally implant CVAD using one of these systems. Furthermore, since the hand-held electromagnetic device is portable and relatively inexpensive, it can be purchased by centers without fluoroscopic capabilities for the insertion of either peripheral or central CVADs. Similar to a prior study where the majority of catheters were placed by the right internal jugular,9 we have shown that catheters can be accurately placed from several central 562
venous approaches using the EMCLS. The sensor at the tip of the guidewire or catheter can be identified, even when in abnormal locations. In these situations, the hand-held detection device can be used to accurately reposition the catheter. The use of this system allows the operator to be free of exposure to radiation and the burdensome lead x-ray gowns. Radiation exposure may be significant to surgeons and personnel who are present for multiple catheter placements using fluoroscopy. Direct exposures to levels above 5,000 mRem are considered a risk factor for cancer.8 The exposure to the surgeon and operating room personnel within 1 m of the field is 1/10th of 1% the exposure to the patient.8 Although seemingly insignificant, with repeated cumulative events, radiation exposure can reach concerning levels. Electromagnetic catheter locator systems may eliminate the risk of cumulative radiation exposure to surgeons and OR personnel. Similar to prior studies,7 cost analysis in this study indicated a statistically significant cost reduction in catheters placed via EMCLS versus standard fluoroscopic techniques. Fluoroscopic equipment and personnel are not utilized with the EMCLS, resulting in radiology cost savings. The cost of the EMCLS includes the purchase of the hand-held electromagnetic detector and the EMCLS compatible catheters, which may have a higher cost than standard catheters. This may be the reason why cost reduction did not reach statistical significance in all subgroups. However, the device may be used for multiple catheter placements, allowing the initial purchase cost of the hand-held device to be distributed over many patients. Thus, as more catheters are placed we anticipate cost savings in all subgroups. The favorable results from this study has stimulated our institution to purchase a second EMCLS for use in our main operating area.
CONCLUSION The use of an electromagnetic catheter locator system for CVAD placement significantly reduces radiation exposure and cost without compromising the accuracy of placement or the complication rate when compared with standard fluoroscopic-assisted placement.
REFERENCES 1. Carre MC, Vega JML, Carles J, et al. Central venous brachial catheter (P.A.S. Port TM) and catheter scanning system (CathFinder TM). J Surg Oncol. 1994;55:190 –193.
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2. Finney R, Albrink MH, Hart MB, Rosemurgy AS. A cost effective peripheral venous port system placed at the bedside. J Surg Res. 1992;53:17–19. 3. Rubenstein EB, Fender A, Rolston KV, et al. Vascular access by physician assistants: evaluation of an implantable peripheral port system in cancer patients. J Clin Oncol. 1995;13:1513–1519. 4. Morris P, Buller R, Kendall S, Anderson B. A Peripherally implanted permanent central venous access device. Obstet Gynecol. 1991;78:1138 –1142. 5. Pullyblank AM, Pearce SZ, Tanner AG, et al. Comparison between peripherally implanted ports and externally sited catheters
for long-term venous Access. Ann R Coll Surg England. 1994;76: 33–38. 6. Schuman E, Ragsdale J. Peripheral ports are a new option for central venous access. J Am Coll Surg. 1995;180:456 – 460. 7. Frank JL, Halla B, Garb JL, Reed WP. Fluoroscopy-free placement of standard chest wall subcutaneous chronic venous access devices. Ann Surg Oncol. 1997;4:597– 602. 8. Mettler FA, Upton AC. Medical Effects of Ionizing Radiation. 2nd ed. Philadelphia: WB Saunders; 1995. 9. Starkhammar H, Bengtsson M, Kay DA, Shapiro AR. Central venous catheter placement using electromagnetic position sensing: a clinical evaluation. Biomed Instrument Technol. 1996;30:164 –170.
DISCUSSION
small study size, yet you go on to conclude that the use of electromagnetically guided catheters resulted in a cost reduction. How did you come to this conclusion? Edward Nelson, MD (Salt Lake City, Utah): You said that this technique is as accurate or more accurate than fluoroscopy. The way I’ve always used fluoroscopy, the catheter is either in the right position or I know that it’s not. In other words, the accuracy should be essentially 100%. In your fluoroscopy group, do you use a small amount of dye to document position? I’ve never accepted leaving the OR suite using fluoroscopy guidance unless I knew the catheter position was right, or in a patient who had a central thrombosis or other anatomic problem, I was willing to accept it being not correctly placed.
Ronald A. Squires, MD (Oklahoma City, Oklahoma): This study retrospectively reviews the efficacy and the utility of using an electromagnetic probe to direct the placement of central venous catheters, thereby avoiding the need for fluoroscopy. The data are consistent with several similar articles in the literature, as has been outlined for you. This technology does seem to offer several advantages over traditional imaging techniques in terms of cost, convenience, and safety. Eliminating the need for fluoroscopy could greatly reduce the radiation exposure to our patients as well as to our surgical teams. In addition, intraoperative delays and scheduling conflicts could be potentially avoided when fluoroscopy is required simultaneously in multiple procedural suites. Finally, cost could be reduced not only by the direct elimination of fluoroscopy itself, but also by allowing the access placement to be performed in minor surgical suites not designated for fluoroscopic use. After reviewing the manuscript, I would like to ask the authors the following questions: First, did you identify any patients who failed electromagnetic positioning attempts who subsequently required fluoroscopic guidance? If so, were there any risk factors identified such as numerous previous central lines or central vein thromboses that would suggest the patient needed fluoroscopic assistance from the beginning? Second, the manuscript states that this technique was used for ports, Hickman’s, and Groshong catheters. What size catheters were placed? Although we are all reasonably comfortable inserting small introducers blindly using Seldinger technique, our institution has found it to be safer to insert the larger and quite stiff 12.5-French dilators under direct fluoroscopic visualization. You appear to be using patient retail cost for the calculation of catheters, x-ray, and fluoro time, while using hospital wholesale cost when figuring the expense of the electromagnetic wand. This can create a cost bias against fluoroscopy within your study. Do you charge a patient for the use of the wand within the procedure room? Also, I did not identify any cost difference noted in your study between the catheters with built-in electromagnetic sensor wires and standard catheters. In our institution, electromagnetic catheters are more expensive than their traditional counterparts. Finally, you noted in your paper that the cost difference analysis did not reach statistical significance owing to your
CLOSING Honnie Bermas, MD: To answer whether we had to convert to fluoroscopic placement of any lines, we found that most of the problems were technical. For some reason, our EMCLS device didn’t function correctly. Most of the time the batteries needed to be changed, and we needed to send it back to the manufacturer. We didn’t really run into any other difficulties in terms of needing to convert. We didn’t use any 12.5-French catheters. The largest that we used was an 8. We usually used a single- or a doublelumen catheter. We haven’t used this technique for vast cath or anything larger. There is a cost difference between these catheters and standard catheters, which we did take into account in calculating our cost differential. We found that the cost reduction wasn’t statistically significant, but we feel that since so many more catheters can be placed using this device, the cost of the device can be averaged over the number of catheters. Our feeling is that over time as you inserted more catheters, you would save money in the long run. In terms of the accuracy of the placement, we did find that the fluoroscopy group was outside of the range of the SVC and the RA in a greater proportion of patients, and I can’t explain why that is the case. Regarding the last question, I think physicians feel a little bit more confident with fluoroscopy, since they’re looking right at the catheter, but the learning curve for this machine is quite speedy, and once you learn to use the device over the chest wall, you can gain quite a bit of confidence in your technique.
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