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Peripherally Inserted Central CathetersPeripherally Inserted Central Catheters: Bigger Is Not Necessarily Better FREE TO VIEW

Samuel Z. Goldhaber, MD, FCCP
Author and Funding Information

From Cardiovascular Medicine Division, Venous Thromboembolism Research Group, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School.

Correspondence to: Samuel Z. Goldhaber, MD, FCCP, Harvard Medical School and the Cardiovascular Division, Venous Thromboembolism Research Group, Brigham and Women’s Hospital, 75 Francis St, Boston MA 02115; e-mail: sgoldhaber@partners.org

Financial/nonfinancial disclosures: The author has reported to CHEST the following conflicts of interest: Dr Goldhaber has received grant support from Sanofi-Aventis, EKOS, Bristol-Myers Squibb, Boehringer Ingelheim, and J&J, and has been a consultant to Boehringer Ingelheim, Bristol-Myers Squibb, Eisai, Sanofi-Aventis, EKOS, and Medscape.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).

© 2011 American College of Chest Physicians

Chest. 2011;140(1):6-7. doi:10.1378/chest.11-0257
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As a cardiologist caring for hospitalized patients, I frequently order the placement of peripherally inserted central catheters (PICCs). This approach is safer than using the jugular, subclavian, or femoral vein for venous access, and the procedures for line placement are standardized and routine. Our hospital, like many others, has a nursing team that specializes in the insertion of these indwelling central venous catheters. Their expertise, honed by years of experience and aided by improvements in catheter/needle kit technology, maximizes the likelihood of successful line placement and minimizes the chance of complications such as fluid infiltration into surrounding tissues or catheter infection. PICCs are especially useful for the prolonged infusion of IV amiodarone and pressor agents. And when patients recover from the cardiovascular crisis that required hospitalization, PICCs are vital for hospital discharge planning, to facilitate extended courses of antibiotics such as vancomycin.

Although I have a special interest in venous thrombosis, including upper extremity thrombosis, I have not previously considered the implications of catheter size vs vein size when ordering a PICC. My major concern has been to avoid the complications of fluid infiltration, infection, and thrombosis. I have favored brisk flow of fluids through the PICC and, therefore, have gravitated toward the largest lumen catheter that is practical for a particular patient’s vein size. My clinical focus has centered on the inner lumen diameter size of the catheter, rather than the overall internal plus external size of the catheter. Brisk flow through the internal lumen of the catheter makes it unlikely that the infusion pump alarm will sound a warning that the ordered amount of fluid cannot be infused. However, a large PICC is susceptible to the paradoxical effect of slow flow due to venous obstruction. Under these circumstances, flow slows presumably because the catheter tip is at least partially obstructed. Such a catheter must be causing at least some trauma to the vein wall. Thus, despite the best of intentions, conditions for a “perfect storm” can arise and predispose the patient to upper extremity venous thrombosis.

The article by Nifong and McDevitt1 in this issue of CHEST (see page 48) is intriguing and thought provoking. These authors force us to ponder the competing three issues of blood and fluid flow, catheter size, and vein size. Where do we begin to weigh the relative importance of catheter size vs blood flow rates? There are no randomized controlled trials, nor are there large observational studies to guide us. The problems posed have not been adequately dealt with. Nifong and McDevitt’s mechanical and mathematical modeling is based on physical principles and provides new groundwork to use scientific methods to tackle an important practical clinical problem. Figure 2 of their article illustrates the experimental apparatus that they constructed to simulate annular flow in a vein with a catheter. In Figure 1, they profile the velocity of laminar flow with a centrally placed obstruction. Figure 3 shows that fluid flow is markedly decreased by a centrally located obstruction.

What are the practical implications of this pioneering work? First, the authors have introduced the cardiopulmonary community to the complexities of venous blood flow rates and catheter to vein ratio “tradeoffs.” Their work should encourage more modeling to be undertaken. Second, we need to begin observational studies in normal volunteers and in hospitalized patients in which we quantitate vein size, catheter size, and blood flow rates. Ultrasound provides a useful bedside tool for measuring vein size. Determining venous blood flow rates accurately and noninvasively will be more difficult. Third, after sufficient preliminary data are gathered, we should begin clinical trials among hospitalized patients requiring PICCs to optimize blood flow and minimize vein trauma and central catheter obstruction. Optimal alignment of catheter size to vein size will be the key to success.

These steps will take time and require patience. In the meantime, what can we do as clinicians caring for our hospitalized patients? I intend to spend more time discussing catheter size and catheter selection with our PICC nursing team. For the patients for whom I am attending physician, I will begin to examine venous sites for PICCs, assess vein size and body habitus, and consider whether the distal end of the catheter might be vulnerable to physiologic or anatomic central obstruction. I will become more involved in PICC selection with regard to catheter length and diameter. Nifong and McDevitt have made a convincing case for paying more attention to these issues, which were wrongly considered mundane but which, in fact, are pertinent themes to maximize patient safety.

The immediate lesson for us clinicians is that one size of a PICC does not fit all. We have to individualize catheter selection. I would consider using a larger catheter when a power port is necessary to inject contrast or when multiple lumens are required. But bigger is not necessarily better. To avoid obstruction at the distal tip of the catheter, I will choose a smaller lumen catheter whenever the smaller size will suffice, thus optimizing venous blood flow because of a more favorable catheter to vein ratio.


Nifong TP, McDevitt TJ. The effect of catheter to vein ratio on blood flow rates in a simulated model of peripherally inserted central venous catheters. Chest. 2011;1401:48-53. [CrossRef] [PubMed]




Nifong TP, McDevitt TJ. The effect of catheter to vein ratio on blood flow rates in a simulated model of peripherally inserted central venous catheters. Chest. 2011;1401:48-53. [CrossRef] [PubMed]
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