Pediatric emergency medicine trisk 1167

Procedures that can be accomplished by the generalist or ED personnel include
establishing access, performing phlebotomy, and infusing fluids or medications.
The general procedure for establishing access and patency is similar for both
tunneled and totally implanted devices ( Table 135.6 ). Aseptic technique is
mandatory. Because tincture of iodine solution can damage Silastic catheters, 2%
chlorhexidine gluconate or povidone-iodine solution is used to clean the site.
Recent studies have demonstrated lower bloodstream infection rates with the use
of 2% tincture of chlorhexidine and chlorhexidine-impregnated dressings.
Antimicrobial locks, including ethanol locks, and antibiotic/antifungal locks are
often instilled daily in patients with long-term CVCs who have limited venous
access and a history of recurrent central line infections, and those who are a
highest risk of severe sequelae from an infection. Locks dwell from 4 to 24 hours.
Ethanol locks are highly recommended for at-risk patients, but can only be
instilled into silicone catheters due to risk of degradation of polyurethane, in
which case, and antibiotic lock may be ordered.
Clamps or hemostats with teeth should not be used, as these instruments can
damage the external portion of the catheter. In addition, smaller (less than 3 mL)
syringes can generate too much pressure inside the catheter, causing catheter
breakage. Therefore, 5- or 10-mL syringes are recommended to flush the system;
never force flush against resistance. Fluid or medications should never be infused
until patency is established because the risk of administering these solutions into
a nonvascular space is high. To prevent air emboli, all clamps must remain closed
when any part of the circuit is open. For accurate blood test results, the amount of
blood that needs to be withdrawn and discarded prior to obtaining a laboratory
sample is 3 mL from a tunneled CVC and 5 mL from a totally implanted CVC.
Recent literature has demonstrated that compared with heparin, tissue-type
plasminogen activator (tPA) is more successful in reducing the chances of clot
formation in central venous hemodialysis catheters. However, further research on
other types of catheters and cost analyses remain to be performed to determine if
tPA should replace heparin in this regard.

TABLE 135.6
TIPS FOR THE ROUTINE USE OF INDWELLING VENOUS ACCESS
DEVICES
Aseptic technique
Do not use clamps or hemostats with teeth for external catheters
Flush entire intravenous circuit before accessing system
Always close clamps when any part of the circuit is open
Clean the needleless cap for 15 seconds and allow to dry prior to every entry
into the cap
Do not infuse fluids or medications until patency is established
Flush the catheter/port with 5–10 mL of saline between medications
Flush cap or port with heparin when procedure is complete
When a tunneled CVC is accessed, these steps should be followed:
1. Before accessing the system, prime the intended IV circuit, including connection
tubing, with saline to remove air. Clamp the IV tubing closed.
2. Clamp any external portions of central catheter on the protected area near the
hub.
3. Clean the cap on the end of the system using at last 15 seconds of mechanical
friction, preferentially with a device, such as Site-Scrub, that contains alcohol,
povidone iodine, or chlorhexidine. Allow the solution to dry. Repeat cap
cleaning prior to each entry.
4. Flush the system with 3 to 5 mL of saline in a 5- to 10-mL syringe and then
aspirate 3 to 5 mL of blood to check patency; do not use this as a blood sample
—discard. Absence of blood return may indicate the formation of fibrin sheath
on internal catheter tip or malpositioning of the tip. If no blood returns, consider
treatment with tPA if a fibrin sheath is suspected. If not successful after two
doses, consider a dye study and do not use the catheter for vesicant infusion.
5. Draw off blood needed for laboratory analysis and administer medications or
fluids as needed. Flush again with saline and then either flush the device with

heparin or connect the IV tubing to the needleless cap using Luer lock
connections.
6. If the catheter is to be heparin-locked, clamp the line prior to removal of the
flush syringe; this maneuver is not necessary for the saline-flushed Groshong
device.
7. If the needleless cap is removed, discard the old needleless cap and replace it
with a new one using sterile technique.


The procedure differs slightly when accessing a totally implanted CVC or port.
Because intact skin is penetrated, the use of a topical anesthetic cream before
access should be considered when feasible. After leaving the topical anesthetic on
for the manufacturers’ recommended time, it should be wiped off and the skin
should be cleansed with 2% chlorhexidine gluconate, alcohol, or povidone-iodine.
Povidone-iodine should not be cleaned off with alcohol. Using a sterile technique,
triangulate the port body with three fingers, and insert a Huber needle through the
skin directly into the reservoir diaphragm when resistance is met at the back of
the reservoir. The needle should be secured in place and patency should be
confirmed with aspiration and flushing. After use, the totally implanted device
must be flushed using 3 to 5 mL of heparin (10 units/mL). When the port is not
being used, patency is maintained with 3 to 5 mL of 100 units/mL flush on a
monthly basis.
Complications resulting from accessing CVCs include occlusion, air embolus,
catheter breakage or displacement, and infection. Although most of these
complications can be avoided if care is taken to maintain aseptic technique, the
clinician should be aware of their diagnosis and management.

Clinical Findings/Management
Catheter Occlusion
Difficulty drawing blood or infusing fluid through a CVC can be the result of

catheter malposition or occlusion. The catheter may be positioned against a vessel
wall, or fibrin or blood may clot in the lumen. In addition, various precipitates
can occlude the lumen of the catheter. Waxy precipitates can result when
parenteral nutrition solutions contain combinations of fat, protein, and
carbohydrate, and particulate precipitates can result from the poor solubility of
calcium and phosphorus. IV phenytoin (especially when administered in a
glucose-containing solution) and diazepam can also precipitate.
Children who require IV medications or fluids at home may present for shortterm management of catheter occlusions.
Increasing the venous pressure gradient along the catheter can facilitate
phlebotomy. These maneuvers include having the patient hold his or her arms
above the head, cough or perform Valsalva maneuver, and placing the patient in
Trendelenburg position. If blood still cannot be drawn, 3 mL of saline should be
used to gently irrigate the CVC. Never flush against resistance as the pressure can
force a clot into the bloodstream or rupture the catheter, particularly if the
practitioner uses too much force or too small a syringe. Care should be taken to
observe the catheter for a balloon “aneurysm,” a sign of impending rupture.


Totally implanted systems are much less likely to clot than are tunneled
catheters. This situation is fortunate because irrigating the clot is more difficult to
perform on a totally implanted system.
Specific agents may help dissolve precipitates or clots. For waxy precipitates,
70% ethanol should be used. For particulate precipitates, 0.1N hydrochloric acid
(HCl) or 8.4% sodium bicarbonate should be used depending on the pH of the
drugs/solutions infusing prior to the precipitate formation. Fibrinolytic agents
such as tPA (up to 2 mg, dependent on catheter size) may dissolve a blood clot,
and similar to HCl, may be used up to two times in 24 hours if necessary. Ethanol
should be used only one time per episode. tPA infusions may be started at the
suggestion of the surgical or interventional radiology consultants, who should be
involved in the treatment plan if initial attempts are unsuccessful.

Air Embolism
Failure to maintain a closed system during manipulation of indwelling venous
catheters can result in embolism of air into the chambers of the heart. Passage of
the embolus to the systemic or pulmonary circulation can result in severe and
irreversible tissue damage.
Air embolus can cause a patient to experience sudden onset of tachypnea,
tachycardia, hypotension, or loss of consciousness. Other diagnoses that should
be considered in patients with these symptoms are pneumothorax, liberation of
septic emboli, and direct cardiac insult. If an air embolus is suspected, the patient
should be placed in the left-sided Trendelenburg position and oxygen should be
administered. In addition, the indwelling catheter should be clamped and remain
unused as other peripheral access is obtained.
Catheter Breakage
The family members and physicians caring for the child with a tunneled catheter
may have considered the nightmare of catheter breakage and subsequent
exsanguination. Although catheter breakage is a distinct possibility, most events
occur during routine care rather than during playtime and therefore the blood loss
is easily apparent and correctable. A tunneled catheter can acquire a small hole
from inadvertent needle puncture or even ordinary wear and tear. Totally
implanted catheters, in contrast, are less susceptible to local events or wear and
tear. However, trauma to the area can result in detachment of the proximal portion
of the catheter from the implanted port.
Leakage of blood or fluid from the externalized portion of a tunneled catheter
is easily noticed. Externalized catheters must be immediately clamped proximal