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Peripherally Inserted Central Catheter (PICC) Line Placement

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Last Update: January 10, 2024.

Continuing Education Activity

Peripherally inserted central catheters (PICCs) are a type of central venous catheter that offers long-term central venous access in inpatient and outpatient settings. PICCs are used to administer medications (eg, antibiotics, antifungals, vasoactive agents, and chemotherapy), total parenteral nutrition, fluids, and to collect blood samples. Depending on the patient's clinical condition, available resources, and the healthcare professional's preference, PICC line insertion can be performed with and without fluoroscopy. PICC line insertion under fluoroscopic guidance produces a continuous real-time Xxray image, allowing the clinician to ensure correct line placement. This technique works well for patients with small-diameter veins and unclear anatomy, reducing the risk of dangerous misplacement. PICCs are effective, but serious complications can occur during the line placement or while in use. This activity describes the indications, contraindications, and complications associated with PICC line placement and highlights the role of the interprofessional team in ensuring safe practice.

Participating clinicians will enhance their knowledge of the benefits of PICCs, including reduced intraprocedural complications, lower maintenance costs, outpatient functionality, and a decreased risk of catheter-related bloodstream infections. Additionally, clinicians will gain insights into using PICCs in neonatal care, where they have proven effective in increasing nutrient input, minimizing the need for frequent cannula/catheter insertions, and optimizing medical resource utilization. This review also emphasizes the importance of interprofessional teamwork in ensuring safe PICC line practices.

Objectives:

  • Identify the indications for PICC line placement.
  • Apply the steps for inserting a PICC line with and without utilizing fluoroscopy.
  • Assess the complications associated with PICC line placement.
  • Collaborate and coordinate amongst an interprofessional team to facilitate safe PICC line placement and improve patient outcomes.
Access free multiple choice questions on this topic.

Introduction

Peripherally inserted central catheters (PICCs) were introduced to establish central venous access for extended administration of medication and nutrition. Their widespread adoption into clinical practice as an alternative to central venous catheters (CVCs) inserted into the jugular vein is based upon their reduced risk of intraprocedural complications, maintenance cost, functionality in an outpatient setting, and a lower rate of catheter-related bloodstream infections (CRBSI).[1][2] 

Improvements in perinatal care have led to a significant increase in the survival of very low birthweight and extremely low birthweight infants. Using PICCs in neonates to deliver parenteral nutrition has been demonstrated to increase nutrient input, prevent the need for frequent cannula/catheter insertions, and conserve medical resources.[3]

A PICC may be inserted at the bedside by several practitioners or a radiologist who may opt for fluoroscopic guidance to ensure intraoperative safety and correct catheter positioning. A PICC is a 50 cm to 60 cm long catheter with up to 3 lumens, most commonly placed into a peripheral vein in the arm and terminates in proximity to the cavoatrial junction.[4] These catheters may be used and left in place for months before removal if appropriately maintained.[5]

Anatomy and Physiology

The right basilic vein’s size and proximity to the skin make it the attempted vein of choice for PICC placement.[6] The basilic vein is usually accessed between the axilla and the antecubital fossa. Originating from the dorsal venous network of the hand, the basilic vein travels on the medial aspect of the upper extremity. After combining with the brachial vein, the axillary vein is formed, which becomes the subclavian vein at the border of the first rib and continues centrally to become the brachiocephalic (innominate) vein.[7] The right and left innominate veins combine to form the superior vena cava. A right basilic venotomy location provides the least tortuous path toward the superior vena cava. This vein is thought to have the least number of valves and provides a more optimal access angle.[4] 

If the basilic vein is not accessible or occluded, an attempt at accessing the right brachial vein may be attempted.[4] There is a higher risk of accidental arterial puncture with this venous access location with the brachial artery nearby. Alternatively, the cephalic vein may be used for access. If the venous system of the right upper extremity is not accessible due to superficial infection, trauma, or obstruction, a left-sided approach may be attempted.

In neonates, head and neck veins, such as temporal and posterior auricular veins, can be used for PICC placement. Additionally, saphenous veins in the lower extremity are suitable for PICC line insertion.

Indications

Due to their low infection rate, PICCs are indicated in patients who require intravenous (IV) therapy for lengths of time that range from weeks to months.[8]

Indications for PICC line placement include:

  • IV infusion of irritant medications (chemotherapy) [8]
  • Total parenteral nutrition (TPN) [9][8]
  • Long-term administration of medications (antibiotics, antifungals) [8]
  • Monitoring of interventions (central venous pressure and repeat blood sampling) [10]
  • Patients with poor peripheral access (reducing the number of needle punctures to the skin)
  • Multiple blood transfusions [11]
  • Desire to discontinue the use of umbilical catheters in neonates while maintaining central access
  • Aberrant central venous anatomy

Fluoroscopic PICC line placement is used in patients with challenging anatomy, providing real-time visualization for precise placement. 

Contraindications

There are no absolute contraindications to PICC placement. However, there are relative contraindications, and these include the following:

  • Skin infections
  • History of venous thrombosis at the insertion site
  • Trauma or burns at the insertion site [12][4]
  • Active bacteremia [13]
  • Allergic reactions to contrast material and elevated serum creatinine if the placement is guided by venography using iodinated contrast agents
  • Prior radical mastectomy with lymph node dissection of the side of PICC insertion
  • In patients with chronic kidney disease, those undergoing hemodialysis or in whom hemodialysis is anticipated (to minimize the potential for thrombosis-related loss of upper extremity veins associated with PICC placement) [14]   
  • Moderate to severe coagulopathy or thrombocytopenia
  • Patient agitation
  • Procedure refusal by the patient

Additionally, fluoroscopic procedures are contraindicated in pregnant patients unless the procedure is medically necessary for patient well-being. PICC placement can be performed using ultrasound without fluoroscopy in these patients.

Equipment

Commercially, several catheter designs with different catheter materials, such as silicone and polyurethane, are available. These designs also vary regarding catheter diameters and the number of lumens. Catheters are manufactured with 3 fundamental tip configurations: end hole, staggered tip, and valve-tipped. Valved catheters prevent backflow of blood into the catheter when the system is open.

The modified Seldinger technique is the most widely used method for PICC placement.

Most hospitals have kits that contain standard equipment for central venous access. Items needed for the procedure include:

  • Sterile draping material
  • Ultrasound and probe with sterile probe cover
  • Ultrasound gel
  • Sterile gown, gloves, and cap
  • Measuring tape
  • Chlorhexidine solution
  • Sterile saline flushes
  • Suture material
  • Dressing
  • Local anesthetic (1% lidocaine)
  • PICC catheter
  • Introducer needle
  • Guidewire
  • Dilator
  • Blade
  • Leaded glasses and apron for radiation protection

Personnel

Qualified physicians, registered nurses, or physician assistants can insert PICCs. Nevertheless, many institutions employ specialized teams of PICC nurses.

Preparation

The procedural risks and benefits must be discussed with the patient. The patient is connected to a cardiac monitor to detect arrhythmias that may occur as a result of wire access into the right atrium. The patient is placed supine with the arm abducted and externally rotated. Ultrasound is used to identify and select the appropriate vessel for access.

With the measuring tape, the distance from the antecubital fossa to the midclavicular line is measured, and the tape measure is turned to reach the third intercostal space at the right border of the sternum. This will be the approximate measurement of the catheter. PICCs in the lower extremity are measured from the venipuncture site along the course of the vein to the right of the umbilicus, extending up to the xiphoid.

The area is prepped with an antiseptic solution. The patient is draped with sterile draping material. The sterile cover is placed over the ultrasound probe. Supplies are arranged in a sterile and organized fashion for easy access. Items are in the center of the sterile field. All catheter lumens are flushed with normal saline and clamped shut. Sedation may be given for the procedure.

Technique or Treatment

Ultrasound-Guided Placement of a PICC

Position the arm at a 45-degree to 90-degree angle by the patient's side on an arm board, with the palm facing upward. Directly visualize the access vein with ultrasound and anesthetize the skin and subcutaneous tissue over the area of the vein with 1% lidocaine. Using the access needle, puncture the vein while directly visualizing the needle tip. Ultrasound will confirm the correct positioning of the needle within the vein, as will blood return from the needle. An axial view of the vessel with the ultrasound will allow visualization of the needle tip. Advance the guidewire through the needle. In case the guidewire is advanced too far, cardiac ectopy may be observed, and it is advisable to retract the guidewire. Remove the needle while keeping the wire in place. Using the scalpel, make a small nick in the skin to widen the needle tract to allow more room for the introducer. Thread the introducer and dilator over the wire, through the skin, and into the vein. Trim the catheter to the previously measured length using the scalpel in the PICC kit. Remove the wire and dilator while leaving the introducer in place. Place a finger over the opening of the introducer to avoid air aspiration during removal. Slowly insert the entire length of PICC with the obturator into the introducer sheath. If the catheter is advanced too far, cardiac ectopy may be observed. When employing the ECG-guided technique, the P wave will progressively increase in size as the tip approaches the cavoatrial junction. It will reach its peak and then invert after passing into the atrium. The optimal catheter tip position is achieved when the P wave is at its maximum height, aligning with the cavoatrial junction.[15] Snap open and pull the 2 wings of the sheath apart and alternate advancing catheter between pulls slightly. Aspirate and flush each lumen, checking for blood return. Remove the obturator and place caps on the PICC lumens. Secure the catheter to the skin using a locking device and cover it with dressings. A chest radiograph should be obtained to confirm the position of the catheter before the first use.

Fluoroscopically-Guided Placement of a PICC

The procedure is similar to the ultrasound-guided placement, except that contrast material is inserted into the veins before the needle is placed. The guidewire is advanced under fluoroscopic guidance until the tip reaches the cavoatrial junction. The PICC catheter is threaded over the guidewire, ensuring the tip is positioned correctly under fluoroscopic guidance. 

Pediatric Considerations

  • Sedation may be required in young patients.
  • Some small veins, less commonly accessed in adults, may be considered for PICC placement in pediatric patients. These include the superficial temporal, posterior auricular, greater and lesser saphenous, and popliteal veins.
  • When inserted from a lower extremity, the position of the catheter tip should be in the inferior vena cava and above the diaphragm.[16]

Postprocedure Care

The dressing and venotomy site should be inspected to check for bleeding and erythema. Dressings should be changed at least once weekly or per hospital policy and manufacturer guidelines. After each use, the PICC should be flushed with normal saline and heparin solution.

Complications

PICCs are generally inserted safely, but complications may arise relating to device insertion, functionality, or postprocedure infection. The common complications tend to be vascular.[17] Vascular complications such as accidental arterial puncture, bleeding, vasospasm, and pseudoaneurysm formation have been reported in the literature following PICC insertion.[18][19]

In addition to arterial injury, peripheral nerves and brachial nerve plexuses in the upper extremity may be damaged.[18] Although accessed peripherally, the central termination of the catheter has been reported to rarely cause cardiac tamponade, pneumothorax, air embolism, and thoracic duct injury due to incorrect terminal positioning.[18][17] Proper ultrasound training and fluoroscopic guidance to ensure proper catheter position can lower the chance of these complications.

Mechanical catheter occlusions can occur by either intraluminal or extraluminal causes. Intraluminal obstruction most commonly occurs from coagulated blood or infusion products that have precipitated. Extraluminal obstruction usually results from fibrin sheath formation, thrombus at the tip, or incorrect catheter positioning.[18] This may pose issues for patients requiring regular PICC use. Using a thrombolytic agent can lyse the fibrin sheath and restore the flow. Occlusion rates have drastically dropped with catheter design and product material usage advances.[20] 

A systemic review and meta-analysis of 64 studies, including 29,503 patients, demonstrated that PICCs are associated with a higher risk of deep vein thrombosis (DVT) than CVCs. The risk was higher in critically ill patients and with malignancy.[21] The risk of DVT is also higher in patients with a prior history of DVT, obesity, and other comorbidities such as diabetes mellitus. Increasing catheter size is significantly associated with increased risk and can be minimized by choosing a small-size catheter based on an appropriate catheter-to-vein ratio.[22]

A recently published study exploring the PICC-related complications in 3,285 patients reported that central line-associated bloodstream infection (CLABSI) and symptomatic DVT were the most common complications. Most of the CLABSIs were monomicrobial and caused by gram-positive bacteria.[23] A study by Nasia et al concluded that the PICC-associated bloodstream infection rate was 2.4% or 2 to 5 per 1000 catheter days.[24] This rate was similar in another study on ICU patients comparing CVCs with PICCs. PICCs were associated with an infection rate of 2.2 per 1000 catheter days versus 6 per 1000 catheter days for CVCs.[25] These rates were significantly higher than patients with a PICC receiving outpatient care at 0.4 per 1000 catheter days.[24] 

Recent studies support the fact that PICC carries less risk for the development of infection than CVCs.[26] When comparing PICC and tunneled CVCs for TPN administration, PICC was associated with a significantly lower rate of CRBSI.[27] The primary pathway for infection is the migration of skin organisms at the insertion site into the cutaneous catheter tract, leading to the colonization of the catheter tip. Infection can also occur due to contamination of the infusate or the catheter hub.

Clinical Significance

CVCs have proven to be a secure and effective means for long-term medication and fluid administration in hospitalized patients, especially in intensive care, surgical, and oncological units. Over time, their utility has expanded to include outpatient settings.

PICC usage has increased significantly since the advent of central venous access. However, PICCs do have advantages over other types of catheters for central venous access, some of which include:

  • Ability to use in an outpatient setting [28]
  • Lower risk of infection in inpatient settings
  • Ability to remain in for months at a time for long-term treatments and diagnostics [29]

Fluoroscopic PICC line placement is becoming more commonly used in clinical practice. The use of fluoroscopic guidance eliminates the need for a postprocedure chest x-ray. Real-time fluoroscopic guidance allows the practitioner to confidently place the PICC and ensure that they have inserted the catheter into the correct vessel, ensure the line does not have any kinks or coils, and that the tip terminates in the correct anatomical location.

Fluoroscopically guided PICC placement is not without caveats. Only some facilities can perform fluoroscopically guided procedures. Critically ill patients, like those in the ICU, may face challenges traveling to the radiology department for the procedure. Ultrasound-guided procedures without fluoroscopy would have to be performed at the bedside in these patients. In addition, pregnant patients would be better suited to performing the procedure without fluoroscopic guidance to avoid unnecessary excess radiation to the fetus. Fluoroscopic guidance can aid in cases of PICC placement in patients with tortuous anatomy. Improving healthcare professional's knowledge and exposure to this technique will ultimately improve patient outcomes and reduce the risk of infection, hemorrhage, and vascular injury.

Enhancing Healthcare Team Outcomes

A collaborative and well-coordinated approach among physicians, advanced practitioners, nurses, pharmacists, and other health professionals is essential for providing patient-centered care, optimizing outcomes, ensuring patient safety, and enhancing team performance related to PICC line management. Clear communication, shared responsibilities, and ongoing education are critical components of a successful interprofessional team caring for patients with PICC lines.

The medical team responsible for caring for the patient must consider the indications, weigh the risks and benefits, and make an informed decision regarding PICC line placement and whether the patient would benefit from fluoroscopic guidance for the procedure. Radiologists either carry out the fluoroscopic PICC placement or oversee the procedure while a skilled physician assistant performs it. Following the line placement, the nursing staff provides the aftercare. Nurses are responsible for day-to-day care, education, and monitoring of patients with PICC lines, reporting any concerns promptly. Pharmacists are responsible for ensuring accurate and safe medication administration through PICC lines, providing expertise in drug selection and dosing.

Careful monitoring and maintenance of these lines are paramount in preventing procedural complications. If a complication should arise, effective communication of the entire multidisciplinary team will aid in treating the complication and preventing occurrences in the future. In addition, many healthcare facilities also have teams of infectious disease staff to monitor the number and root cause of catheter-associated bloodstream infections. This data aids in the institutional protocol changes to provide a safer service for patients needing care. Joint educational sessions enhance mutual understanding of each professional's role and responsibilities regarding PICC line care. 

Review Questions

References

1.
Amerasekera SS, Jones CM, Patel R, Cleasby MJ. Imaging of the complications of peripherally inserted central venous catheters. Clin Radiol. 2009 Aug;64(8):832-40. [PubMed: 19589422]
2.
Johansson E, Hammarskjöld F, Lundberg D, Arnlind MH. Advantages and disadvantages of peripherally inserted central venous catheters (PICC) compared to other central venous lines: a systematic review of the literature. Acta Oncol. 2013 Jun;52(5):886-92. [PubMed: 23472835]
3.
Ainsworth S, McGuire W. Percutaneous central venous catheters versus peripheral cannulae for delivery of parenteral nutrition in neonates. Cochrane Database Syst Rev. 2015 Oct 06;2015(10):CD004219. [PMC free article: PMC9250057] [PubMed: 26439610]
4.
Gonzalez R, Cassaro S. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Sep 4, 2023. Percutaneous Central Catheter. [PubMed: 29083596]
5.
Kwon S, Son SM, Lee SH, Kim JH, Kim H, Kim JY, Kim JI, Moon IS. Outcomes of bedside peripherally inserted central catheter placement: a retrospective study at a single institution. Acute Crit Care. 2020 Feb;35(1):31-37. [PMC free article: PMC7056959] [PubMed: 32131579]
6.
Jeon EY, Cho YK, Yoon DY, Hwang JH. Which arm and vein are more appropriate for single-step, non-fluoroscopic, peripherally inserted central catheter insertion? J Vasc Access. 2016 May 07;17(3):249-55. [PubMed: 26847734]
7.
Nguyen JD, Duong H. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 14, 2023. Anatomy, Shoulder and Upper Limb, Veins. [PubMed: 31536282]
8.
Cheung E, Baerlocher MO, Asch M, Myers A. Venous access: a practical review for 2009. Can Fam Physician. 2009 May;55(5):494-6. [PMC free article: PMC2682308] [PubMed: 19439704]
9.
Botella-Carretero JI, Carrero C, Guerra E, Valbuena B, Arrieta F, Calañas A, Zamarrón I, Balsa JA, Vázquez C. Role of peripherally inserted central catheters in home parenteral nutrition: a 5-year prospective study. JPEN J Parenter Enteral Nutr. 2013 Jul;37(4):544-9. [PubMed: 22898795]
10.
Sanfilippo F, Noto A, Martucci G, Farbo M, Burgio G, Biasucci DG. Central venous pressure monitoring via peripherally or centrally inserted central catheters: a systematic review and meta-analysis. J Vasc Access. 2017 Jul 14;18(4):273-278. [PubMed: 28665469]
11.
Hashimoto Y, Fukuta T, Maruyama J, Omura H, Tanaka T. Experience of Peripherally Inserted Central Venous Catheter in Patients with Hematologic Diseases. Intern Med. 2017;56(4):389-393. [PMC free article: PMC5364190] [PubMed: 28202859]
12.
Linenberger ML. Catheter-related thrombosis: risks, diagnosis, and management. J Natl Compr Canc Netw. 2006 Oct;4(9):889-901. [PubMed: 17020667]
13.
Hicks MA, Popowicz P, Lopez PP. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): May 26, 2023. Central Line Management. [PubMed: 30969633]
14.
Vascular Access 2006 Work Group. Clinical practice guidelines for vascular access. Am J Kidney Dis. 2006 Jul;48 Suppl 1:S176-247. [PubMed: 16813989]
15.
Pittiruti M, Bertollo D, Briglia E, Buononato M, Capozzoli G, De Simone L, La Greca A, Pelagatti C, Sette P. The intracavitary ECG method for positioning the tip of central venous catheters: results of an Italian multicenter study. J Vasc Access. 2012 Jul-Sep;13(3):357-65. [PubMed: 22328361]
16.
Wu Y, Yan J, Tang M, Hu Y, Wan X, Li X, Chen Q, Li X. A review of neonatal peripherally inserted central venous catheters in extremely or very low birthweight infants based on a 3-year clinical practice: Complication incidences and risk factors. Front Pediatr. 2022;10:987512. [PMC free article: PMC9659812] [PubMed: 36389348]
17.
Franklin I, Gilmore C. Placement of a peripherally inserted central catheter into the azygous vein. J Med Radiat Sci. 2015 Jun;62(2):160-2. [PMC free article: PMC4462988] [PubMed: 26229681]
18.
Hertzog DR, Waybill PN. Complications and controversies associated with peripherally inserted central catheters. J Infus Nurs. 2008 May-Jun;31(3):159-63. [PubMed: 18496060]
19.
Soto E, Ananthasekar S, Passman MA, Myers RP. Microsurgical management of a brachial artery pseudoaneurysm in a 41-day-old infant. J Vasc Surg Cases Innov Tech. 2021 Mar;7(1):133-136. [PMC free article: PMC7921195] [PubMed: 33718684]
20.
Smith JR, Friedell ML, Cheatham ML, Martin SP, Cohen MJ, Horowitz JD. Peripherally inserted central catheters revisited. Am J Surg. 1998 Aug;176(2):208-11. [PubMed: 9737634]
21.
Chopra V, Anand S, Hickner A, Buist M, Rogers MA, Saint S, Flanders SA. Risk of venous thromboembolism associated with peripherally inserted central catheters: a systematic review and meta-analysis. Lancet. 2013 Jul 27;382(9889):311-25. [PubMed: 23697825]
22.
Evans RS, Sharp JH, Linford LH, Lloyd JF, Tripp JS, Jones JP, Woller SC, Stevens SM, Elliott CG, Weaver LK. Risk of symptomatic DVT associated with peripherally inserted central catheters. Chest. 2010 Oct;138(4):803-10. [PubMed: 20923799]
23.
Wan R, Gu L, Yin B, Cai S, Zhou R, Yang W. A six-year study of complications related to peripherally inserted central catheters: A multi-center retrospective cohort study in China. Perfusion. 2023 May;38(4):689-697. [PubMed: 35236188]
24.
Safdar N, Maki DG. Risk of catheter-related bloodstream infection with peripherally inserted central venous catheters used in hospitalized patients. Chest. 2005 Aug;128(2):489-95. [PubMed: 16100130]
25.
Velissaris D, Karamouzos V, Lagadinou M, Pierrakos C, Marangos M. Peripheral Inserted Central Catheter Use and Related Infections in Clinical Practice: A Literature Update. J Clin Med Res. 2019 Apr;11(4):237-246. [PMC free article: PMC6436570] [PubMed: 30937113]
26.
Pitiriga V, Bakalis J, Theodoridou K, Kanellopoulos P, Saroglou G, Tsakris A. Lower risk of bloodstream infections for peripherally inserted central catheters compared to central venous catheters in critically ill patients. Antimicrob Resist Infect Control. 2022 Nov 09;11(1):137. [PMC free article: PMC9647909] [PubMed: 36352414]
27.
Hon K, Bihari S, Holt A, Bersten A, Kulkarni H. Rate of Catheter-Related Bloodstream Infections Between Tunneled Central Venous Catheters Versus Peripherally Inserted Central Catheters in Adult Home Parenteral Nutrition: A Meta-analysis. JPEN J Parenter Enteral Nutr. 2019 Jan;43(1):41-53. [PubMed: 30035806]
28.
Mielke D, Wittig A, Teichgräber U. Peripherally inserted central venous catheter (PICC) in outpatient and inpatient oncological treatment. Support Care Cancer. 2020 Oct;28(10):4753-4760. [PMC free article: PMC7447660] [PubMed: 31970514]
29.
Matsuzaki A, Suminoe A, Koga Y, Hatano M, Hattori S, Hara T. Long-term use of peripherally inserted central venous catheters for cancer chemotherapy in children. Support Care Cancer. 2006 Feb;14(2):153-60. [PubMed: 15999262]

Disclosure: Matthew Montanarella declares no relevant financial relationships with ineligible companies.

Disclosure: Ankit Agarwal declares no relevant financial relationships with ineligible companies.

Disclosure: Brian Moon declares no relevant financial relationships with ineligible companies.

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