Part 3: Catheter Maintenance Protocols

1. Flushing Protocols

1.1 General Principles

Flushing maintains catheter patency, prevents intraluminal occlusion, and clears the lumen of incompatible medication residues. Every CVAD lumen must be flushed according to a defined protocol. An occluded lumen should never be left untreated simply because another lumen remains functional — prolonged fibrin formation within untreated lumens constitutes a risk factor for catheter-associated bloodstream infection.¹²³

Standard Flushing Solution:

Preservative-free 0.9% sodium chloride (normal saline) is the standard flushing solution for all CVADs. Multiple studies and meta-analyses have demonstrated that normal saline alone is equivalent to heparin-containing solutions for maintaining patency of valved catheters, and accumulating evidence supports saline-only flushing for non-valved devices as well.²³⁴

Flushing Technique — Pulsatile (Push-Pause) Method:

The pulsatile or “push-pause” flush technique generates turbulent flow within the catheter lumen that is more effective at removing protein deposits, fibrin, and medication residues than continuous laminar flow:²³

Connect a prefilled 10 mL normal saline syringe to the needleless connector
Inject 1–2 mL of saline in a brief, firm push
Pause briefly (approximately 1 second)
Repeat the push-pause cycle until the full flush volume has been delivered
Maintain positive pressure while disconnecting (technique varies by connector type — see Section 4)

Syringe Size Requirement:

A minimum syringe barrel size of 10 mL should be used for all CVAD flushing to limit the pressure generated within the catheter lumen. Smaller syringes (e.g., 3 mL or 5 mL) generate higher intraluminal pressures that may exceed the burst pressure of the catheter, risking catheter rupture or damage. This is particularly important for silicone catheters, which have lower burst pressure tolerance than polyurethane catheters.²³

Exception: When instilling thrombolytic agents or catheter-clearance agents, the specific volume required may necessitate a smaller syringe. In these situations, gentle pressure must be applied; excessive force should never be used.

1.2 Flushing Volumes and Frequency by Device Type

Device Type	Flush Volume (0.9% NaCl)	Frequency	Additional Notes
Implanted port — in active use	≥10 mL before and after each infusion	Each treatment session	Flush all lumens; verify blood return before use
Implanted port — between treatment cycles	≥10 mL	At each access (typically q4–8 weeks)	See maintenance flushing interval discussion below
Implanted port — not in active treatment	10 mL NaCl + 3–5 mL heparin 100 units/mL	Every 4–12 weeks	Evidence supports extending to q3 months⁴⁵
PICC — in active use	≥10 mL before and after each infusion	Each use and every 12–24 hours if not infusing	Daily when accessed but not actively infusing
PICC — between uses	≥10 mL NaCl	Every 7 days (minimum)	Flush at each dressing change
Tunneled catheter — in active use	≥10 mL before and after each infusion	Each use and every 12–24 hours	Per lumen
Tunneled catheter — between uses	≥10 mL NaCl ± heparin lock	Every 7 days (minimum)	Per institutional protocol
Nontunneled CVC	≥10 mL before and after each infusion	Every 8–12 hours when not infusing	Per lumen

Pediatric Adjustments:

For pediatric and neonatal patients, flush volumes should be adjusted based on catheter priming volume and patient size. Typical pediatric flush volumes range from 3 to 5 mL of 0.9% sodium chloride. For neonates and patients with fluid restrictions, the flush volume should equal at least twice the internal catheter volume.³⁶

1.3 Maintenance Flushing Intervals for Implanted Ports

The optimal maintenance flushing interval for implanted ports not in active treatment has been an area of evolving evidence. Traditional practice called for flushing every 4 weeks. Current evidence and guideline recommendations allow more flexibility:⁴⁵

Extending maintenance flushing intervals to every 3 months (12 weeks) using 10 mL of 0.9% sodium chloride followed by 3 to 5 mL of heparin at a concentration of 100 units per milliliter has demonstrated safety and efficacy for maintaining adequate port patency while reducing patient burden.
Some institutions have adopted intervals of every 8 to 12 weeks based on institutional data.
Patients should be counseled that longer intervals between port flushes are acceptable and do not compromise device function, to reduce unnecessary clinic visits and improve quality of life for cancer survivors retaining ports.
Research indicates that 0.9% sodium chloride alone may be equally effective as heparin-containing solutions for maintaining port patency in some contexts, though combined saline-heparin protocols remain the prevailing standard for maintenance of deaccessed ports.

1.4 Flushing Between Incompatible Medications

Between administration of incompatible solutions or medications through the same lumen, flush with a minimum of 10 mL of preservative-free 0.9% sodium chloride. This removes residual medication from the catheter lumen and prevents precipitation or chemical reaction within the catheter.¹²

When compatibility between two medications is unknown or unconfirmed, they should be treated as incompatible and the lumen should be flushed between administrations. If multiple incompatible infusions are required simultaneously, separate catheter lumens should be used when available.¹

2. Locking Protocols

2.1 Heparin Lock

Heparin locking remains the traditional standard for maintaining patency of non-valved CVADs between uses:²³

Standard Heparin Lock Protocol:

Parameter	Adult	Pediatric
Concentration	10–100 units/mL	10 units/mL (most common)
Volume	3–5 mL per lumen	Volume equal to 110% of catheter priming volume
After flushing with	≥10 mL 0.9% NaCl	≥3 mL 0.9% NaCl (adjusted to patient size)
Frequency	After each use; per maintenance interval if not in use	Same

Considerations for Oncology Patients:

Heparin-induced thrombocytopenia (HIT) is a recognized complication of heparin exposure. While the risk from low-dose catheter locking is very small, clinicians should maintain awareness, particularly in patients with prior HIT history.
For patients with confirmed or suspected HIT, saline-only locking should be used. Alternative locking solutions such as 4% sodium citrate may be considered per institutional protocol.
When heparin lock is prescribed, use preservative-free heparin to minimize potential toxicity from cumulative benzyl alcohol exposure.

2.2 Normal Saline Lock

Accumulating evidence supports the use of 0.9% sodium chloride alone (without heparin) for locking valved CVADs (e.g., Groshong catheters) and increasingly for non-valved devices:²³⁴

Multiple randomized controlled trials have found no significant difference in catheter patency between saline and heparin locking for PICCs
Saline locking eliminates the risk of heparin-related adverse effects
Institutional protocols should define whether saline-only or saline-plus-heparin locking is used, based on device type and local outcomes data

2.3 Antimicrobial Lock Therapy

Antimicrobial lock therapy (ALT) involves instilling a concentrated antimicrobial solution into the catheter lumen and allowing it to dwell for an extended period (typically 8–24 hours). ALT is used for two purposes in oncology:⁷⁸

Prophylactic ALT: May be considered for patients with recurrent CLABSI or those at very high infection risk (e.g., prolonged neutropenia, patients on long-term TPN). The most commonly studied agents include:

Ethanol (70%)
Taurolidine-citrate
Minocycline-EDTA
Vancomycin-heparin

Routine prophylactic ALT for all oncology CVADs is not universally recommended but may be appropriate in selected high-risk populations per institutional protocol.⁷

Therapeutic ALT: Used as adjunctive therapy for catheter-related bloodstream infection when catheter salvage is attempted (see Part 4 for full CLABSI management).

3. Port Access and Deaccess Procedures

3.1 Pre-Access Assessment

Before accessing an implanted port, the clinician must conduct a thorough assessment:⁴⁵⁹

Visual inspection and palpation of the port site for swelling, tenderness, erythema, drainage, or skin breakdown
Assessment for venous collaterals on the chest wall, which may indicate underlying venous occlusion
Evaluation of overlying skin integrity for erosion of the port body through tissue
Assessment for signs of catheter-associated DVT including unilateral limb swelling, pain, or discoloration
Review of treatment plan to confirm the port is the appropriate access device for the prescribed therapy

Contraindications to Port Access:

When any of the following are present, the port should not be accessed and clinical evaluation should be sought:

Signs of port pocket infection (erythema, swelling, fluctuance, drainage, tenderness)
Skin erosion over the port body
Signs suggesting venous thrombosis (new venous collaterals, ipsilateral arm edema)
Suspected port malfunction based on prior access difficulties

3.2 Port Access Procedure

Equipment Required:

Noncoring (Huber) needle — appropriate gauge and length
Sterile gloves
CHG-alcohol skin antiseptic
10 mL prefilled 0.9% sodium chloride syringes (2–3)
Heparin lock solution (if indicated by protocol)
TSM dressing and needle securement materials
CHG-impregnated dressing (if infusion duration >4–6 hours)
Extension set with needleless connector (if not integrated into the needle)

Noncoring Needle Selection:

Parameter	Guidance
Gauge	Smallest gauge accommodating the prescribed therapy; 22-gauge for standard chemotherapy; 19–20 gauge for blood product transfusion, apheresis, or power injection
Length	Must reach the bottom of the port reservoir; assess subcutaneous tissue depth by palpation; lengths typically range from 0.75 to 1.5 inches
Safety features	Safety-engineered needles with retractable mechanism required
Power injection	Only power-injectable noncoring needles for contrast injection procedures

Step-by-Step Access Technique:

Perform hand hygiene
Explain the procedure to the patient; address pain management
Apply topical anesthetic if indicated (EMLA or LMX cream, applied 30–60 minutes prior) — standard in pediatric oncology; offered to adult patients based on preference
Prepare equipment on a sterile field
Palpate the port to identify the portal body and septum; locate the center of the septum
Cleanse the skin over the port with CHG-alcohol using back-and-forth friction for ≥30 seconds; allow to dry completely
Don sterile gloves
Prime the noncoring needle and extension tubing with 0.9% sodium chloride
Stabilize the port body between the thumb and first two fingers of the nondominant hand by grasping the edges of the port through the skin
With the dominant hand, insert the noncoring needle perpendicular to the port septum in a single firm motion until the needle tip contacts the back of the port reservoir (a distinct “click” or resistance is felt)
Orient the needle bevel away from the outflow channel (opposite to the catheter attachment point) for optimal flushing efficacy⁵
Aspirate to confirm blood return
Flush with 10 mL of 0.9% sodium chloride using pulsatile technique; assess for ease of flush and absence of swelling or pain
Secure the needle with sterile tape strips or stabilization device
Apply CHG-impregnated dressing if indicated
Apply TSM dressing over the entire site
Label dressing with date of access and initials
Connect infusion or lock per protocol

Blood Return Assessment:

Presence of blood return should be confirmed at each access and before initiating any infusion
Blood return confirms that the catheter tip is intravascular and the device is patent
If blood return is absent, troubleshoot per the algorithm in Section 3.5 before initiating vesicant chemotherapy
Critical safety point: Vesicant chemotherapy should never be initiated through a port without confirmed blood return, unless alternative patency confirmation (e.g., radiographic dye study) has been obtained³⁹

3.3 Noncoring Needle Replacement

The frequency of noncoring needle replacement during continuous port use should follow institutional protocol. When continuous infusion is ongoing:⁴⁵

Replace noncoring needles per institutional policy, typically every 7 days when a continuous infusion is running
Current evidence is insufficient to establish a definitive maximum dwell time for noncoring needles
Inspect the needle insertion site and reassess needle stability at each dressing change
Replace the needle immediately if dislodgement, leaking, or signs of infection are noted

3.4 Port Deaccess Procedure

Stop all infusions
Flush with 10 mL of 0.9% sodium chloride using pulsatile technique
If heparin locking is indicated: instill heparin lock solution (3–5 mL of 100 units/mL) while maintaining positive pressure
Stabilize the port body with the nondominant hand
Remove the noncoring needle in a single, smooth motion perpendicular to the skin
Engage the safety mechanism on the noncoring needle immediately upon removal
Apply a small adhesive bandage over the needle puncture site
Dispose of the needle in a sharps container
Document the deaccess procedure, flush volumes, and any concerns

3.5 Troubleshooting Absent Blood Return

When blood return cannot be obtained from a CVAD, a systematic approach is required before concluding the device is malfunctioning:¹²³

Step 1: Assess External Factors

Check the entire infusion system from the connector to the insertion site
Ensure all clamps are open
Assess the needleless connector for obstruction or malfunction — remove and replace if suspect
For ports: confirm the needle is fully seated (palpate for contact with the port base)
For PICCs/tunneled catheters: check external catheter length for evidence of migration

Step 2: Attempt Patient Repositioning

Have the patient raise the ipsilateral arm above the head
Ask the patient to cough or perform Valsalva maneuver
Change patient position (sit up, turn to side, slight Trendelenburg)
These maneuvers alter intrathoracic pressure and may shift the catheter tip away from a vessel wall or valve

Step 3: Attempt Gentle Aspiration

Attach a syringe directly to the catheter hub (bypassing extension tubing)
Use a 10 mL syringe and apply gentle aspiration
Alternate gentle aspiration with gentle instillation of small saline volumes

Step 4: If Blood Return Remains Absent but Catheter Flushes Freely

This pattern suggests a “withdrawal occlusion” — possibly caused by a fibrin tail, fibrin sheath, or catheter tip position against the vessel wall
Consider thrombolytic therapy (alteplase) per institutional protocol (see Part 4)
Obtain imaging to evaluate catheter tip position if thrombolysis is unsuccessful

Step 5: If Catheter Cannot Be Flushed

Do NOT force flush against significant resistance — this risks catheter rupture
Consider thrombolytic therapy for suspected thrombotic occlusion
Assess for chemical occlusion if incompatible medications were recently administered
Obtain imaging and consult vascular access specialist or interventional radiology

4. Needleless Connector Management

4.1 Types and Selection

Needleless connectors are mandatory components of all CVAD administration systems, eliminating sharps exposure during routine catheter access:²³

Types:

Neutral displacement: Neither refluxes blood into the catheter tip nor displaces fluid during connection/disconnection; no specific clamping sequence required
Positive displacement: Displaces a small volume of fluid forward upon disconnection, designed to minimize blood reflux into the catheter tip
Negative displacement: Draws a small volume of fluid backward upon disconnection; requires clamping before disconnection to prevent blood reflux

Clamping Sequence by Connector Type:

Connector Type	Sequence When Disconnecting
Neutral displacement	Clamp at any time during disconnection; no specific sequence required
Positive displacement	Disconnect first, then clamp (to allow positive fluid displacement)
Negative displacement	Clamp first, then disconnect (to prevent blood reflux)

4.2 Connector Change Frequency

Needleless connectors should be changed:²³

At minimum every 96 hours (4 days)
Whenever removed for any reason
When blood or debris is visible within the connector
When integrity is compromised
Per manufacturer recommendations if these specify shorter intervals
At each tubing change

4.3 Connector Disinfection (“Scrub the Hub”)

Before every access of a needleless connector, the connector membrane must be disinfected:²⁷⁸

Scrub with 70% isopropyl alcohol using friction for ≥5–15 seconds (institutional protocols vary; some specify up to 15 seconds)
Allow to dry completely before accessing (approximately 10–30 seconds)
Alternatively, use a commercial passive disinfection cap that remains attached to the connector between accesses
Passive disinfection caps containing 70% isopropyl alcohol have demonstrated CLABSI reduction in multiple studies and should be used when feasible, particularly in oncology patients⁷⁸

5. Blood Sampling Through CVADs

5.1 General Principles

Blood sampling through CVADs reduces venipuncture burden in oncology patients, who typically require frequent laboratory monitoring. However, attention to technique is essential to ensure specimen integrity:²³

Discard Method:

Pause all infusions running through the catheter for at minimum 1–2 minutes before drawing the sample (longer for specific medication levels)
Disinfect the needleless connector
Aspirate and discard a volume of blood equal to 1.5–2 times the catheter priming volume (typically 3–5 mL for adult CVADs) to clear the lumen of flush solution and any infusing medications
Draw the required laboratory specimens
Flush the catheter with 10–20 mL of 0.9% sodium chloride after sampling

Push-Pull (Mixing) Method:

Aspirate 5–6 mL of blood into a syringe
Reinfuse the blood into the catheter
Repeat this push-pull cycle 3–5 times to clear the lumen
On the final aspiration, draw the sample
This method conserves blood volume, which is particularly valuable in anemic oncology patients and pediatric patients
Flush the catheter with 10–20 mL of 0.9% sodium chloride after sampling

5.2 Special Considerations for Oncology Laboratory Draws

Laboratory Test	Special Requirement
Blood cultures	Draw from CVAD AND peripheral site for paired cultures when CLABSI is suspected; differential time to positivity helps identify catheter as infection source
Drug levels (aminoglycosides, vancomycin)	Pause the specific drug infusion for adequate washout time before sampling through the same lumen (varies by drug; typically 1–4 hours); draw from a lumen not used for the drug infusion when possible
Coagulation studies (PT/INR, PTT)	Ensure adequate discard volume; heparin contamination from lock solution can falsely elevate PTT; draw from a non-heparin-locked lumen if available
Tumor markers	Adequate discard volume essential; no specific CVAD-related interference known
Blood typing and crossmatch	May be drawn from CVAD per institutional policy; some blood banks require peripheral venipuncture for type and screen

5.3 Blood Sampling Through Implanted Ports

Blood sampling through implanted ports follows the same general principles as other CVADs:⁵⁹

Access the port with an appropriate noncoring needle
Confirm blood return
Use the discard or push-pull method
Flush thoroughly after sampling (minimum 10 mL normal saline)
If the port was accessed solely for blood draw and no infusion is planned, deaccess after flushing and locking

6. Administration Set Management

6.1 Tubing Change Intervals

Administration set change intervals are a key component of CLABSI prevention:²⁷⁸

Infusion Type	Tubing Change Interval
Standard continuous IV fluids	No more frequently than every 96 hours but at least every 7 days
Intermittent (secondary) infusions	Replace with each new dose or every 24 hours, whichever comes first
Blood and blood product administration	Replace after each unit or at completion of transfusion
Lipid-containing solutions (including TPN with lipids)	Every 24 hours
Lipid emulsions alone (e.g., propofol)	Every 12 hours (propofol) or per manufacturer
Chemotherapy administration sets	Per institutional protocol; typically changed with each treatment session

6.2 Chemotherapy Administration Set Considerations

For cytotoxic chemotherapy administration:

Use Luer-lock connections throughout the infusion system to prevent accidental disconnection and hazardous drug exposure
Closed-system transfer devices (CSTDs) are recommended during chemotherapy preparation and may be used during administration per institutional hazardous drug handling policy
Administration sets used for vesicant chemotherapy should allow close monitoring of the infusion site
All chemotherapy administration sets should be handled as hazardous waste per institutional and regulatory requirements

7. Patency Assessment Summary

A CVAD is considered patent when the clinician can successfully flush all catheter lumens without encountering resistance, following confirmation of blood return from each lumen.¹²

Patency Assessment Protocol (Recommended at Each CVAD Use):

Disinfect the needleless connector
Aspirate for blood return (present = patent; absent = troubleshoot per Section 3.5)
Flush with ≥10 mL 0.9% sodium chloride using pulsatile technique
Assess for resistance during flushing (none = patent; resistance = investigate per Part 4)
Assess for swelling, leaking, or patient pain during flushing (any present = stop and evaluate)
If the device is patent, proceed with prescribed therapy or lock per protocol

References

Gorski LA. Phillips’s Manual of IV Therapeutics: Evidence-Based Practice for Infusion Therapy. 8th ed. FA Davis; 2023. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Gorski LA, Hadaway L, Hagle ME, et al. “Infusion therapy standards of practice.” J Infus Nurs, 44(1S), S1-S224, 2021. Infusion Nurses Society (INS). doi:10.1097/NAN.0000000000000396 ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Hawes ML, Sochor A, Davis LN, McGlauflin W, eds. “AVA Adult Clinical Practice Guidelines.” Journal of the Association for Vascular Access (JAVA), 31(Suppl), 2026. Association for Vascular Access (AVA). ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Chou P-L, Jui-Ying F, Chia-Hui C, et al. “Current port maintenance strategies are insufficient: view based on actual presentations of implanted ports.” Medicine, 98(44), 1-9, 2019. doi:10.1097/MD.0000000000017757 ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Schulmeister L. “Implanted venous ports.” In: Camp-Sorrell D, Matey L, eds. Access Device Standards of Practice for Oncology Nursing. Oncology Nursing Society (ONS); 2017:65-73. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Giordano P, Saracco P, Grassi M, et al. “Recommendations for the use of long-term central venous catheter (CVC) in children with hemato-oncological disorders: Management of CVC-related occlusion and CVC-related thrombosis.” Annals of Hematology, 94(11), 1765-1776, 2015. doi:10.1007/s00277-015-2481-1 ↩︎
Buetti NM, Marschall J, Drees M, et al. “Strategies to prevent central line-associated bloodstream infections in acute-care hospitals: 2022 Update.” Infect Control Hosp Epidemiol, 43(5), 553-569, 2022. Society for Healthcare Epidemiology of America (SHEA). doi:10.1017/ice.2022.87 ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Schiffer CA, Mangu PB, Wade JC, et al. “Central venous catheter care for the patient with cancer: American Society of Clinical Oncology clinical practice guideline.” J Clin Oncol, 31(10), 1357-1370, 2013. American Society of Clinical Oncology (ASCO). doi:10.1200/JCO.2012.45.5733 ↩︎ ↩︎ ↩︎ ↩︎
Guiffant G, Durussel JJ, Flaud P, Vigier JP, Merckx J. “Flushing ports of totally implantable venous access devices, and impact of the Huber point needle bevel orientation: experimental tests and numerical computation.” Med Devices (Auckl), 5(1), 31-37, 2012. doi:10.2147/mder.s30029 ↩︎ ↩︎ ↩︎