Demystifying the Central Line

Roger, a 51-year-old with lung cancer, was well known by our EMS service. For more than a year, he had steadily declined from the ravages of cancer and chemotherapy. This time, when EMS arrived on scene, Roger was responding to verbal stimuli. His wife reported he had been vomiting and had diarrhea for 12 hours. He was obviously volume-depleted and needed a fluid bolus and transport to the hospital.

The paramedics knew from previous experience that Roger was a difficult IV start. They had been unsuccessful many times in the field and had watched ED nurses and physicians also struggle to gain venous access. As the lead paramedic began searching for a peripheral IV site, Roger's wife reported that, since his last visit, a PORT-A-CATH® had been surgically inserted into Roger's chest wall for delivering IV fluids and medications.

Central Venous Catheter
An increasing number of patients like Roger are being sent home with their central venous catheters (or central lines) still in place. Patients who traditionally remained in the hospital for weeks or months now go home in a few days, but require continuing medical care after discharge, including intravenous fluid and/or medication administration. As a result, EMS providers have a fairly good chance of encountering a patient with a central venous catheter.

In nearly every case, it is acceptable to access these devices to administer parenteral fluids or medications. Although central lines are fairly simple to access and monitor, lack of familiarity with the equipment, fear of the unknown or fear of harming the patient might prevent EMS from considering the use of such devices.

Reasons for a Central Line
Patients have central lines for many reasons, the most common being for long-term medication administration, like chemotherapy for cancer or blood transfusion in chronic anemics. TPN (total parenteral nutrition)-a combination of carbohydrates, proteins, lipids, electrolytes and trace elements-is administered through a central line to patients who are unable to eat normally. Another group includes patients who receive intermittent doses of vaso-irritating medications, such as antibiotics for Lyme disease or postoperative osteomyelitis. Some patients have poor venous access and, due to their underlying medical history, require frequent hospitalization. Some of these patients may have some sort of central venous access device.

Similarly, there are patients with medical conditions that require intermittent venous access for blood sampling, fluid administration or drugs who are not hospitalized frequently. An example might be a brittle diabetic with poor veins who has frequent hypoglycemic events. Such a patient may be treated in the home by paramedics and released, providing there is a responsible adult in the home to feed and monitor the diabetic.

Renal or kidney failure patients on dialysis have implanted central venous catheters. It is generally unacceptable to access the renal patient's catheter because of the medications used to flush the line to prevent clotting. A central line with gauze wrapped around the ports or with a medication sticker should not be accessed unless there is no doubt that the catheter is used for purposes other than dialysis.

Important Points for ALS Providers
Following are several key points common to each line that you encounter:

• When using needleless caps, povidone-iodine is the preferred cleansing agent. Let it dry completely, or to 90 seconds, as this is how it works effectively.
• If you are unable to aspirate or flush, it may be a positional problem or external kinking.
• Use the methods described earlier to enhance flow. If these measures don't work, consider alternative methods for venous access.
• Make sure clamps are closed, except when aspirating, flushing or infusing.
• Always aspirate before flushing or infusing. This prevents embolization of any clots that may have formed in or around the catheter, as well as any air bubbles.
• Aspirating prevents inadvertent bolusing of the patient with heparin or other medication.
• Run the IV as per protocol. If protocols allow provider discretion, run the IV at a rate appropriate to the patient's condition, or at a TKO rate if only administering medications and the patient's fluid status is adequate.
• Access a central line only if a patient needs fluid infusion or medication administration.
• Not all catheters contain anti-reflux valves.
• Do not delay transport of a critically ill or injured patient to access a central line catheter on-scene.

Central Line Types/Placement
All central lines end in the same place: a major blood vessel like the superior vena cava. Central lines are inserted in several locations-usually in the antecubital fossa of either arm or somewhere on the patient's chest. EMTs and paramedics may expect to see three general types of central catheters in the field: peripherally inserted central catheters (PICC lines), HICKMAN® catheters and BROVIAC® catheters, and PORT-A-CATHs®.

Peripherally Inserted Central Catheters (PICC Lines)
PICC catheters, which are usually used in patients receiving antibiotics for extended periods of time, are inserted in the antecubital fossa of an arm by a specially trained nurse or radiologist. Venapuncture is initially accomplished with a standard peripheral catheter. Once venous access is gained, the central catheter is inserted through the peripheral catheter and threaded to a predetermined length based on pre-procedure measurements. The distal tip of the catheter usually lies in the superior vena cava; however, it may be inserted to the subclavian vein or just up to a mid-brachial point. PICC lines are extremely flexible, thereby affording the patient nearly unlimited use of the arm. The lines contain a positive-negative flow valve at the proximal tip, which, if left uncapped, does not allow air to enter or fluid to escape. In most cases, PICC lines must be removed after three months of dwelling time in the vein.

Although PICC lines do not require heparinization (flushing with the anti-clotting drug heparin) after each use, it is required in some hospitals. Therefore, never assume a PICC line was flushed with saline after its last use. Flushing the line after each use helps to prevent formation of blood clots either in the catheter or at its tip in the vein. Inadvertently flushing a line rather than aspirating prior to use might result in bolusing the patient with heparin or any other medication that may be in the catheter line, resulting in serious consequences for the patient.

Due to the length of the catheter and the internal lumen, PICC lines are not optimal for rapid fluid resuscitation, as in trauma or massive external bleeding. In most cases, fluids may be infused at a fairly rapid rate without harm to the catheter. Using a pressure bag will augment the fluid flow.

Accessing a PICC Line
Accessing the PICC line requires a few pieces of equipment. Use at least a 12 mL syringe, although 20 mL or larger is preferable. The larger the syringe, the less back pressure is applied to the catheter, thus preventing collapse if you inadvertently aspirate too quickly.

If you are simply accessing the line for infusion of fluids, you will only need one syringe; if you wish to obtain blood samples, you will need more than one. You will need a prefilled saline syringe to flush the line after your initial aspiration.

Since most PICC lines have a needleless cap on the end, you will need either povidone-iodine or alcohol swabs and nonsterile gloves.

Following are steps required to access a PICC line:

• Wash your hands and apply nonsterile gloves.
• Using three povidone-iodine swabs, cleanse the end of the catheter and allow to dry. If povidone-iodine swabs are not available, use three alcohol swabs.
• If the cap is needleless, attach the syringe to the cap. If it is not, remove the cap and, without touching the end of the catheter to any surface, quickly attach the syringe. You need not save the cap, as all hospitals have replacement caps.
• Attach additional syringes to obtain blood samples.
• Unlock the clamp prior to aspirating.

Using gentle, even back pressure, withdraw a minimum of 10 mL of blood from the catheter. This will help aspirate any small clots that may have formed at the distal tip of the catheter. Also, if the catheter was flushed with any medications, such as heparin, this step helps to prevent bolusing the patient with the medication. It is safe practice on any central line to close all clamps between steps, since you cannot be positively sure that the catheter has an anti-reflux valve in the line.

After aspiration, flush the catheter gently with 10 mL of sterile normal saline. If you encounter any difficulties aspirating or flushing, inspect the catheter for kinks. You might ask the patient to cough, take a deep breath, shrug his shoulders or turn his head to one side or the other. If you still encounter difficulty aspirating or flushing after using these techniques, it is advisable not to use the catheter. If the line is patent, attach the IV line, unlock the clamp and begin infusing at the prescribed rate of flow.

BLS Assists
As stated earlier, it is highly unusual for a BLS provider to access a central line. If you are assessing, treating and transporting a patient with a central line, consider an ALS intercept if the patient:

• Has ABC life threats
• Has altered mental status or is V, P or U on the AVPU scale
• Is hypovolemic-in shock
• Has unstable vital signs
• Has overdosed
• Is experiencing chest pain or signs/symptoms of stroke.

Some EMS systems pair a BLS with an ALS provider.
In these systems, the EMT-Basic plays a critical role in assisting the paramedic with complex procedures like fluid infusion and medication administration. Become familiar with the equipment used for central line access and the steps where an EMT-Basic can assist a paramedic or critical care transport nurse with central line access.

HICKMAN® catheters and BROVIAC® catheters
HICKMAN® catheters and BROVIAC® catheters are single or multilumen catheters that are surgically inserted into the upper chest by a physician. The catheter's distal tip is then tunneled through the chest to the superior vena cava.

It is unlikely that EMS providers will encounter this device, but patients are occasionally discharged home with one. HICKMAN® catheters are usually not used for ambulatory patients because the free-hanging lumens may become entangled in clothing or other material, with a risk of catheter dislodgement or removal.

HICKMAN® catheters and BROVIAC® catheters do not have anti-reflux valves like PICC lines, so care must be taken to keep the clamps closed except when fluid is actually being removed or infused through the catheter.

If you encounter a HICKMAN® catheter, you must evaluate whether it is used for hemodialysis, as it is similar in appearance to dialysis catheters. If it is a true dialysis catheter, do not use it. Dialysis catheters are always flushed with large doses of heparin after each use and require special flushing techniques.

Accessing HICKMAN® catheters and BROVIAC® catheters
The steps for accessing the HICKMAN® catheters and BROVIAC® catheters are the same as for the PICC line. Several key points apply to this catheter. First, there are only rare instances when it is not flushed with heparin; therefore, you must always remember to aspirate a minimum of 10 mL from each port. Second, it is occasionally positional, which would impede aspiration.

If you encounter difficulty aspirating, ask the patient to turn his head to one side and then the other, shrug his shoulders or take a deep breath. These actions may facilitate aspiration.

The last key point is that these catheters rarely have anti-reflux valves, so it is prudent to close the clamps whenever you are not aspirating, flushing or infusing.

PORT-A-CATH®
The PORT-A-CATH® is a common type of implanted venous access port that resembles a small pacemaker generator in size. It lies subcutaneously (just under the skin), usually in the upper right, but sometimes upper left chest. Like HICKMAN® catheters and BROVIAC® catheters, its distal tip also lies in the superior vena cava. A Huber needle is used to access either a single- or double-lumen PORT-A-CATH®. The advantage of the PORT-A-CATH® is that no external devices emerge from the skin except when the actual infusion occurs.

PORT-A-CATHs® are always heparinized and work well for fluid resuscitation. One major drawback is that PORT-A-CATHs® are sometimes "positional," so the patient may need to move his head to one side or take a deep breath for the catheter to work successfully.

Accessing a PORT-A-CATH®
As previously mentioned, the PORT-A-CATH® is implanted below the surface of the skin, usually in the upper right side of the chest. Since it is subcutaneous, a special needle (Huber needle) must be used to access this catheter. The Huber is a rigid needle with a slight bend at the end and approximately four inches of tubing attached to the needle.

Due to its placement, the steps for accessing the PORT-A-CATH® are slightly different from the other two catheters.

Wash your hands before starting the procedure. Next, assemble all of your supplies; open packages prior to applying gloves, since sterile glove use is preferable for this catheter. Of course, if the situation is critical, simply apply clean procedure gloves.

With the PORT-A-CATH®, you must prepare the skin with povidone-iodine swabs. Locate the catheter on the chest. It usually looks and feels like a raised, silver-dollar-shaped and -sized bulge on the upper right or left side of the chest.

Using the first swab, start at the center of the catheter and, in a circular fashion, swab outward to a distance of about four inches. Repeat this procedure with the second and third swabs. Allow the solution to dry for 90 seconds, as povidone-iodine exerts its antimicrobial effects by the drying process. Time permitting, you may wipe away the povidone-iodine solution from the skin with alcohol, but you must wait the prescribed time.

After skin preparation, the ALS provider will access the port. Remove the needle guard from the Huber needle, holding the needle in your dominant hand. Next, gently stabilize the catheter with your non-dominant hand. This is easily done using the thumb and forefinger and grasping the catheter with the fingers opposite each other. Using the dominant hand, insert the needle through the skin-at a 90-degree angle to the skin-at the center of the catheter until the needle stops. When you hit the bottom of the catheter with the needle, you may need to pull back 1/16" to 1/8". This will depend upon whether you are able to aspirate initially after needle insertion. In some patients, the pull-back step would not be necessary.

After accessing the PORT-A-CATH®, stabilize the needle by placing either a pre-cut 2 x 2 gauze dressing under the wings of the needle or using several small gauze dressings. Cover the dressings with a bio-occlusive dressing or several pieces of tape. This helps prevent movement or removal of the needle while you complete the subsequent steps. The gauze not only stabilizes, but also minimizes irritation of the patient's skin.

Next, aspirate a minimum of 10 mL of blood. Since Ports are heparinized, this step prevents bolusing of the patient with heparin, aids in assuring patency, prevents embolization of any microthrombi in the catheter, and removes air from the Huber needle and tubing. Obtain any ordered blood samples. Flush the line with 10 mL sterile normal saline.

Attach the IV line and run at the prescribed rate. Tape the IV tubing to the patient's chest.

An important step to remember is that the clamp on the Huber needle tubing must always be closed when you are not aspirating, flushing or infusing, as these catheters do not contain anti-reflux valves. If you forget to clamp, you will quickly learn that blood often flows easily out of these catheters.

Although central line catheters are strong and flexible, they occasionally break. If this happens, move the clamp as close to the insertion site as possible and close.

As with HICKMAN® catheters and BROVIAC® catheters, if you encounter difficulty aspirating or flushing, it may be due to the patient's position. Ask the patient to take a deep breath or move his head to one side or the other to facilitate flow. If, despite these measures, you are unable to aspirate or flush, the catheter may be blocked and should not be used.

Central Line Complications
When used properly, the central line catheter may be safely accessed and monitored by a paramedic; however, even with adherence to a stringent protocol and medical control oversight, complications may ensue.

Depending on the patient's position, the central line catheter can occasionally be pinched between the clavicle and first rib as it passes through the subclavian vein, which may compromise fluid infusion. Having the patient shrug his shoulders or lean forward will reduce pressure on the subclavian vein.

Although the central line catheter tip lies in a major vein with flowing blood, microthrombi may form around the distal tip. Introduction of free-flowing fluid may embolize these small clots, resulting in potentially serious complications such as stroke, coronary event, pulmonary embolism or thrombosis in the extremities. To avoid complications, always aspirate at least 10 mL of fluid from the catheter prior to introducing medications or intravenous fluids.

Although unlikely, there may be small amounts of air in the internal lumen of the catheter. Careful priming of all tubing prior to infusion will help eliminate the potential for introduction of air emboli. Again, it is prudent that you aspirate at least 10 mL of fluid prior to infusion in order to withdraw not only fluids in the line but also air.

Important Points for BLS Providers
As you consider the need for an ALS intercept for a patient with a central line, remember these key points:

• Access a central line only if a patient needs fluid infusion or medication administration.
• If the catheter breaks, use the clamp to move it as close to the insertion site as possible, then close.
• Do not delay transport of a critically ill or injured patient to access a central line catheter on-scene.

In most jurisdictions, prehospital central line access is a skill restricted to critical care transport nurses and paramedics. Work with your medical director to write a protocol that meets local, regional or state EMS regulations for central line access.

Contamination or Infection
All catheters should have a protective cap at the end. If the cap in place is needleless and you choose to attach your tubing to the cap, you must swab the cap with a povidone-iodine solution three times and allow it to dry prior to attaching the end of the infusion tubing.

Since most institutions stock a supply of protective caps, it may be more advantageous for you to remove the cap immediately prior to initial aspiration, taking care not to touch anything to the open end. This would be at your medical control's discretion and dependent on provider experience. Just remember to have the clamp closed whenever the cap is off the catheter.

There is a risk that catheters which do not contain anti-reflux valves may allow blood to flow back when they're unclamped and the end cap is off. Unless this goes unnoticed, there should not be great concern for massive bleeding, although it may happen. Again, it is always prudent to keep the clamps closed except when aspirating or infusing.

Catheter Complications
Most catheters are constructed of material that is pliable and fairly resistant to breakage. Prior to accessing, always inspect the catheter for tears or breaks, and with the initial aspiration, check for leakage from the exposed catheter tubing.

Always check for visible kinks. If you have difficulty aspirating, consider the possibility of internal kinking or blockage from a clot. You may need to find alternative peripheral venous access.

Bleeding around the site or difficulty aspirating may be indicative of catheter dislodgement. When moving or transferring the patient, especially one in whom you've already established an infusion, there is a risk of catheter dislodgement. Ensure there is adequate tubing length and that the catheter itself is not caught on cot side rails, sheets or other objects prior to transferring the patient.

Some catheters are sutured into place and are quite stable; however, there is a remote possibility of dislodgement even if sutured to the skin. If a catheter is accidentally removed, place firm pressure on the site for at least 10 minutes with several 4 x 4s, fluffs or a trauma dressing to control bleeding.

Summary
In the prehospital setting, you are most likely to encounter a PICC line, PORT-A-CATH® or HICKMAN® catheter. Others exist, but your chances of seeing them in the field are rare. The basic steps outlined in this article are an introduction to using central lines. I strongly recommend a hands-on session with a knowledgeable instructor who is intimately familiar with the use of these devices.

Joe Redding, RN, BS, BSN, CCRN, CEN. works as a registered nurse in air and ground critical care transport. He previously worked in an emergency department and in medical/surgical intensive care. In addition to nursing, he has taught continuing education courses for paramedics, continues to teach BLS, ACLS and PALS, and works as an independent education consultant/author. He is board-certified in emergency nursing and critical care nursing.

HICKMAN® and BROVIAC® are registered trademarks of C.R. Bard, Inc., and its related company, BCR, Inc.