Fig. 19.1
Pre-procedural US screening to detect anatomical variants. (a) Normal anatomy, (b) abnormal internal jugular vein (V) position (median to the carotid artery), (c) abnormal surrounding structure (*, ganglion), (d) abnormal patency (IJV thrombosis)
USG of the needle brings the needle tip in the lumen of the vessel without damaging surrounding structures (artery, nerve, pleura), helps the catheterization of the vessel, and, for central venous access, places the needle tip in an optimal position to insert the guide wire (GW) (Fig. 19.2).
Fig. 19.2
Role of ultrasound guidance during vascular puncture. (a) (1) Guide the needle in the middle of the vein, (2) avoid transfixion, (3) avoid puncturing surrounding structures, and (b) (4) catheterize the vessel and place the needle tip in an optimal position to insert the guide wire
Post-procedural screening is used to confirm the correct migration of the GW and eventually to detect potential life-threatening complications (severe hematoma, pneumothorax, hemopericardium) (Fig. 19.3).
Fig. 19.3
Post-procedural US screening. (a) Confirmation of the correct migration of the guide wire (arrow) in the brachiocephalic vein. (b) Detection of a severe carotid hematoma (arrows). (c) Left: absence of pneumothorax: positive lung sliding sign in 2D-mode (*, rib); right: seashore sign in M-mode (arrow, pleural line). (d) Absence of hemopericardium (*, ** empty spaces; RV, LV right and left ventricles)
For vascular access, USG has shown an increase in final success rate and in success rate at first attempt and a reduction in complication rate (mainly inadvertent arterial punctures) and in a number of attempts needed to succeed. These factors are extremely important in young children and infants where multiple attempts will lead to potential complications, time consumption, and possible instability (hypothermia, hypotension).
19.1.2 Limitations of Ultrasound Guidance
The availability of the equipment and the learning curve are the two main limitations. The cost of the US machine and the disposable probe covers is consequent but should be balanced with the cost of more complications and sometimes longer procedures with blind landmark techniques. The learning curve is short for US screening but can be much longer for USG and placement of CVC in neonates.
In children, structures are usually superficial offering a nice view of both vessels and needle. The limit of resolution can however be reached in case of very small vessels (radial artery in neonates).
Only few pathological situations, like subcutaneous emphysema, may hamper the use of US.
19.1.3 Guidelines for Ultrasound Guidance During Vascular Access
Different societies in different countries and continents do recommend the use of US for vascular access [2–6]. Table 19.1 summarizes their opinion regarding central and peripheral venous access and arterial access. US screening alone can be useful but is evaluated as insufficient and thus not recommended. For some techniques like the subclavian vein puncture, no comparative study is currently found in the literature, making guidelines impossible or very cautious.
Table 19.1
Guidelines for ultrasound-guided vascular access in children
PVA | ART | PICC | IJV | SCV | FEM | |
|---|---|---|---|---|---|---|
NICE – UK – 2002 [2] | n/a | n/a | n/a | +++ | + | + |
ASA – USA – 2012 [3] | n/a | n/a | n/a | +++ | + | + |
ASEcho – USA – 2012 [4] | no | + D | +++ | +++ | no | + |
International – 2012 [5] | + D | ++ | +++ | +++ | +++ | +++ |
SFAR – France – 2014 [6] | + D | + D | n/a | +++ | no | +++ |
19.1.4 Ultrasound Equipment
High-quality US machines are needed to offer sufficient resolution of small vessels and a correct view of the nerves. Doppler and Zoom functions are mandatory to identify thrombosis and to differentiate or puncture very small vessels. Image storage, diffusion, and sharing should be possible to complete the chard of the patient.
High-frequency (>10 MHz) probes are used because of the usual superficiality of the vascular structures in children (Fig. 19.4). Linear probes (giving a rectangular image) are preferred over the curvilinear probes (lower frequency and resolution, distortion of the image). Small-footprint probes (25 mm) are mandatory to treat infants and neonates; they give more room for the placement of the needle (the “hockey stick” probe gives as much space as possible). If the US equipment is limited to a standard adult linear probe (38 mm footprint) and the child is young, at least US screening should be used (Fig. 19.5). Sterile US probe covers and sterile gel are needed and disposed with the US machine.
Fig. 19.4
High-frequency probes for vascular access. (a) Adult linear, (b) linear small footprint, (c) linear pediatric “hockey stick” (*, more room for needle handling), (d) curvilinear transfontanellar probe (lower resolution and image distortion)
Fig. 19.5
Comparison of adult and pediatric equipment in young children. Adult probes are limited to US screening while small-footprint pediatric probes can be used for both US screening and US needle guidance
Recent new developments in US technology are:
Enhanced needle visualization systems (US beam steering)
Incorporated teaching course in US machines
Wireless US probes facilitation sterile handling (Acuson™ – Siemens®)
GPS needle guidance allowing to predict needle track even before skin puncture (eZGuide™ – eZono®)
19.1.5 Puncture Techniques (Fig. 19.6)
Fig. 19.6
Possible ultrasound-guided puncture techniques for vascular access. By combining two different views of the vessel (SAX and LAX) and two different needle approaches (OOP and IP), four techniques are formed to puncture vessels
Vessels can be visualized by US in two different planes or “views”: the short-axis view or SAX shows a round structure and the long-axis view or LAX a long tubular structure. Patent vessels are anechoic (black) and thrombosed vessels iso- or hyperechoic (from grey to white). Veins are easily compressible, their size varies with respiration, and they may content valves. Arteries are pulsatile and more difficult to compress.
US needle guidance can be performed with two different needle-to-probe alignments or “approaches”: the out-of-plane approach or OOP when the needle is inserted perpendicular to the US beam and is seen as a hyperechoic (white) dot and the in-plane approach or IP when the needle is inserted strictly into and parallel to the US beam and is seen as a hyperechoic (white) line.
With OOP approaches, the vessel is placed in the middle of the screen to lie under the middle part of the probe. The needle is inserted at a distance corresponding to the vessel depth with a flat angle (<45°) to appear in the soft tissues above the vessel (Fig. 19.7). The needle tip is followed by sliding or tilting movements of the probe (Fig. 19.8). Sliding movements, requiring gel on the skin, are used if the site offers enough room for movement. Tilting movements are used if room for probe movement is limited (more frequently in infants and neonates). Probe movements should always precede needle movements because the appearance of the hyperechoic needle tip on the screen is the most obvious pattern recognized by our eyes.
Fig. 19.7
The middle of the screen is the middle of the probe. With OOP needle approaches, placing the vessel exactly in the middle of the screen facilitates the puncture. The needle is inserted with a flat angle (α) under the middle part of the probe to appear above the vessel (*)
Fig. 19.8
To follow the needle tip during OOP approaches, sliding (left side) or tilting (right side) movements of the probe are used. Tilting movements more often used in young children when room for probe movement is limited
With IP approaches, the probe remains in a stable immobile position while the needle is inserted exactly parallel and under the length of the probe (Fig. 19.9). Perfectly inserted, the needle is seen as a bright hyperechoic line. If the needle moves away from this position, it can disappear completely or partially. Needle (or probe) position is corrected to have a constant view of the needle tip and shaft.
Fig. 19.9
To follow the needle during IP approaches, the needle is precisely inserted parallel and centered under the length of the probe. The needle is seen as an hyperechoic line (a). When completely lost, the needle can be retrieved by small sliding movements of the probe (b). If the needle disappears partially during its progression, right-to-left movement of the needle will re-center the needle under the probe (c)
Four combinations of vein “views” and needle “approaches” are used in clinical practice depending on the type and size of the vein, the age of the child, and the preference of the operator:
SAX view with OOP approach: used frequently for peripheral venous and arterial accesses; for jugular, femoral, and axillary access; and for peripherally inserted central catheters (PICCs) insertions.
SAX view with IP approach: used for the access to the internal jugular vein (IJV) by a posterior approach.
LAX view with OOP approach: rarely used, only for the infraclavicular access to the subclavian vein in older children.
LAX view with IP approach: used for the supraclavicular and infraclavicular accesses to the brachiocephalic, subclavian, and axillary veins and can also be used for peripheral accesses when veins are big enough.
19.1.6 Learning Curve
US needle guidance should be trained on gel models, not on patient. Different professional gel models exist that reliably simulate the puncture of small vessels but also the puncture of jugular, femoral, or subclavian veins in children (Fig. 19.10). After “in vitro” training, the first 5–10 punctures should be supervised by an experienced colleague. The variability of the learning curve is important depending on dexterity, three-dimensional orientation, and number of procedures done per week.
Fig. 19.10
Different gel models used for pediatric vascular access training sessions. (a) “Head and torso,” (b) “pediatric vessels,” and (c) “PICC insertion arm” from Blue Phantom® and (d) “vascular access child” from Simulab®
19.1.7 Sterile Setting and Ergonomics (Fig. 19.11)
Fig. 19.11
Sterility and ergonomy. (a) Long sterile drape and probe covers ensure maximal barrier precautions. (b) Hands and US screen are aligned in front of the operator to facilitate handling
Central venous catheter should be inserted by using maximal barrier precautions including cap, mask, sterile gloves, and gown and large sterile drapes and a long sterile probe cover. Transparent sterile drapes are useful to see the anatomy and the chest movements of the child.
The US machine should be placed in front of the operator allowing an alignment of hands and US scream.
19.2 Peripheral Venous Access
19.2.1 Indications
A peripheral venous access (PVA) is mandatory for every anesthesia. For elective surgeries most children will prefer inhalational induction of anesthesia. The PVA is then placed after the child is asleep but before any manipulation of his airway. The success rate of PVA in the operation room is high with a success at first attempt between 68 and 80 % and a rate of impossible access less than 0.5 %, which is 10 times lower than the failure rate in the ward (up to 5 %) [7].
The period between induction and the first intravenous access can be critical. Children with a possible difficult PVA should be detected during the preoperative evaluation to allow specific equipment and/or abilities to be prepared for the time of anesthesia [8] (Table 19.2). Allowing children to drink clear fluids 2 h before anesthesia will facilitate the PVA by limiting dehydration. In case a life-threatening condition occurs before the PVA is found (laryngospasm, major bradycardia or cardiac), the intraosseous route should be used without delay (see Intraosseous Route).
Table 19.2
Anticipating a difficult peripheral venous access is of major importance
Difficult PVA | Tips and technologies |
|---|---|
Young age (2 months–2 years) Former preterm children Prolonged illness Previous difficult iv access No veins seen or palpated preoperatively Obesity Black skin Vasoconstriction Dehydration | Experience in pediatric and neonatal anesthesia Push needle with the thumb (feel the “pop” or “click”) Fill the cannula with saline (faster venous flashback) Wet black skin (increase transparency) Warm up the skin Take EMLA® cream off 10 min before puncture Transillumination Near-infrared technology Ultrasonography |
Failed PVA after induction of anesthesia | |
Stable conditions: call for help, use advanced technologies (ultrasound), go to a CVA | |
Life-threatening condition: call for rapid help, use the intraosseous route | |
In case anesthesia has to be induced intravenously (emergencies, child with a full stomach, risk of malignant hyperthermia, etc.), a technique – or a combination of these techniques – should always be used to reduce pain and possible trauma related to “awake” PVA:
Application of topical anesthetics: EMLA® cream (lidocaine 2.5 %–prilocaine 2.5 %), Ametop® (tetracaine 4 %), or S-Caine® patch (lidocaine 7 %–tetracaine 7 %) can be used. The last two have the advantage to anesthetize the skin more rapidly (within 20–30 min) but have to be removed also earlier (within 30–45 min). EMLA® cream is applied under an occlusive dressing on two different visible veins 60–90 min before puncture. The maximal application time should never exceed 4 h. Optimal puncture conditions are obtained 5–10 min after wiping the cream of the skin (disappearance of the vasoconstriction induced by the prilocaine). In neonates, EMLA® is limited to 0.5 g with a maximal application time of 1 h.
Breathing a mixture of O2 and N2O (with a fraction of N2O between 50 and 70 %) for 3–5 min before puncture causes analgesia and some kind of amnesia.
Hypnosis techniques for school-age children: the Magic Glove, the Magic Pen, the on/off button, or the comfortable location can truly help seriously ill children in case of repeated procedures.
Infiltration of 0.2–0.5 ml of 1 % lidocaine subcutaneously through an insulin or intradermal needle will offer analgesia after a short massage of the skin. Somewhat painful, this technique is mostly used in adolescents.
19.2.2 The Choice of the Vein
The common challenges to find a PVA are encountered between 2 and 18 months of age (chubby babies) or in case of obesity or multiple previous attempts (blood sample or infusions). The most often used puncture sites are listed below and ranked in order of preference (Fig. 19.12):
Fig. 19.12
Different peripheral venous accesses used in children. (a) Dorsal side of the hand, the first choice; (b) external jugular vein, an alternative allowing blood samples (supraclavicular compression); (c) epicranial vein, here used during combined hand and foot syndactyly corrections in Ethiopia; (d) anterior aspect of the wrist, a last and temporary solution
The hand: the first choice in the operating room is a nice vein usually seen or discerned at the dorsal side of the hand between the fourth and the fifth metacarpal bones (sometime between the third and the fourth one) [7]. The second vein runs at the radial side of the wrist but is highly mobile in young children and therefore more difficult to puncture.
The forearm and the antecubital fossa: three major veins run along the forearm – the cephalic, the median antecubital, and the basilic vein. Veins at the forearm are difficult to see in young children due to the relatively high fat layer. At the antecubital fossa, veins can be punctured if they are clearly seen or palpated. Veins should be punctured rapidly under the skin and cannulated over a sufficient distance to avoid early dislodgment and delay recognition of extravasation. In difficult cases, USG should be used instead of blind attempts (risk of arterial puncture or medial nerve damage). At the arm level, basilic–brachial and cephalic veins can’t be seen or palpated anymore and have to be punctured under USG. At that level, longer catheter – like PICCs or midlines – has to be used to provide a sufficient catheterization length (see Peripherally Inserted Central Catheters).
The foot: the internal saphenous vein runs at the anterior border of the medial malleolus and is rarely absent. Ultrasound guidance can be used in case of a negative palpation. This vein is interesting in case of head and neck surgery when massive blood loss is expected (e.g., craniostenosis). Small veins at the dorsum of the foot or the external saphenous vein can also be cannulated.
The scalp: in neonates, branches of the temporal vein can be prominent on the frontoparietal aspect of the head. Digital compression is used to increase vein size and allow cannulation of a short catheter. Shaving the hair locally helps both puncture and fixation.
The neck: the external jugular vein is seen in the majority of children. Digital compression at the lower end of the vein close to the clavicle increases vein size and prevents the vein from collapsing during inspiration. To gain access, the child is placed head-down with a rolled towel under the shoulders and the head turned away from the puncture site. Ultrasound guidance can be used but is rarely needed. Infusion rate and blood flashback can fluctuate with head position and ventilation. Gentle traction on the skin after catheter fixation usually helps to get a blood sample during surgery (can be used as second PVA for this purpose).
The anterior aspect of the wrist: these tiny and superficial veins are sometimes the only vein seen in a chubby baby or an obese child. These veins are fragile and close to other functionally important structures (artery, nerve, tendons). They represent a last and temporary solution.
19.2.3 Standard Procedure
A rapid evaluation of the four limbs usually detects the most attractive site. A tourniquet is placed at the proximal end of the limb without pinching the skin or interrupting the arterial circulation (presence of distal pulse, no skin whitening). Compression and relaxation of the limb’s muscles (“milking”) can increase vein filling. In some cases, the vein can only be palpated but not seen. It is advised to start with distal attempts to allow rescue attempts at a more proximal level without risking leaks of infused fluid through prior puncture sites. Black skin is disinfected to increase light reflexion and visualization of superficial veins.
After disinfection, the skin is stretched and the vein immobilized by the nondominant hand. Pushing the needle with the thumb helps to feel the “pop” or “click” when the bevel pierces the wall of the vein. In neonates or hypovolemic children, venous flashback is sometimes not immediate and can take up to 4 s to appear. It is therefore important to wait long enough after having felt the “click.” To reduce the risk of future extravasation, only half of the length of the cannula should be used to find the vein, allowing the next half to be catheterized into the vein (Fig. 19.13). Filling the needle with saline can speed up slow blood flows in the needle hub. Once the flashback is recognized, the needle is pushed one or a few millimeters further to allow the cannula (shorter than the needle) to enter the vein. After having confirmed venous flashback into the fully inserted cannula, this one is carefully taped, a few milliliter of saline is injected manually, and the infusion bag is connected.
Fig. 19.13
Venous access at the dorsal side of the hand. The left hand stretches the skin to immobilize the vein; the needle is pushed by the thumb to feel the “click.” Only half of the needle length is used to find the vein allowing the next half to be catheterized into the vein (reduced risk of extravasation)
In case of difficult access (vein not seen, not palpated), specific technique can be used:
Transillumination: by bringing light into the tissues, superficial veins are visualized as black lines in a pink environment. This technique showing the track but not the depth of the vein increases success rate in neonates and children less than 3 years old [9]. Depending on the thickness of the limb, the light-emitting diode (LED) is placed under or at the side of the vein (Veinlite Pedi®, Vein Finder®, Wee Sight®). Short application times should be used to prevent potential burns in neonates.
Near–infrared technology: hemoglobin absorbs more infrared light than the surrounding tissues. Portable devices have been developed to detect superficial veins and project their position in real time (VeinViewer®, AccuVein®). Unfortunately the theoretical thickness of skin analyzed (8 mm) seems overstated. Deep unpalpable veins are currently not detected by these devices (Fig. 19.14). The efficacy of these devices remains thus controversial with a possible benefit for black skin [10, 11].
Fig. 19.14
Near-infrared technology. Superficial are clearly shown (a), but more profound veins are not pointed out (b)
Ultrasound guidance (USG): ultrasound allows to detect veins that cannot be seen or palpated. It shows their position, depth, track and patency and can guide the needle into their lumen. Real-time USG reduces the procedure time and the number of attempts needed and increases the success rate in case of difficult PVA [12, 13]. This technique is recommended in these circumstances by different societies [5, 6]. Some experience is needed in young children to bring the needle tip in the lumen of such small vessels. USG is much easier in the operating room after inhalational induction of anesthesia than in the ward when children are awake. The usual sites for USG peripheral access are the ankle with the internal saphenous vein (Fig. 19.15) and the antecubital fossa with the basilic or brachial veins (Fig. 19.16).
Fig. 19.15
Ultrasound-guided internal saphenous vein puncture. SAX view of the vein, OOP needle approach. The skin of the ankle is stretched by a tape to immobilize the vein. *, vein; med mall, medial malleolus
Fig. 19.16
Ultrasound-guided basilic vein puncture at the antecubital fossa. SAX view of the vein, OOP needle approach. Note the proximity of the medial nerve (N) and the brachial artery (A). V basilic vein
19.2.4 Complications
19.2.4.1 Phlebitis
Phlebitis is caused by mechanical or chemical irritation of the venous endothelium. Contributing factors include the material of the cannula (polyurethane is less phlebogenic than teflon), the nature of the solution (pH, tonicity, and composition), the site of insertion (upper limb less prone to phlebitis), and the duration of catheterization.
19.2.4.2 Extravasation
Depending on the nature, concentration, and volume of fluid injected, extravasation can lead to a temporary swelling, compartment syndrome, necrosis, or even delayed limb deformation. It should be prevented by a careful insertion technique (sufficient length of vein catheterization) and surveillance. In the absence of blood return, correct cannulation of the vein is confirmed by a manual injection of saline or by a free flow of the infusion bag placed at a height of 90 cm and this without any subcutaneous swelling detected.
19.2.4.3 Injection of a Residual Anesthetic Medication
Medication injected at a distance of the cannula can remain in the infusion tubing if it is not flushed enough. The fact that anesthetic medication (opiates, muscular relaxant) could remain in the tubing even outside the operating room can be dramatic. The next injection through the same infusion site will bring the medication into the bloodstream with dramatic consequences (apnea, muscular relaxation). It is therefore advised to flush every medication with a volume corresponding to twice the volume of both tubing and cannula.
19.2.4.4 Specific Complications
When puncturing vein at the scalp, care must be taken to avoid accidental catheterization of a branch of the superficial temporal artery. Skin whitening around the site of insertion after a saline test injection is an early sign. The cannula should be removed immediately and a few minutes of compression applied.
Extravasation or hematoma in the neck area can have major (respiratory) consequences. Therefore, a high degree of suspicion should be kept during the (short) use of external jugular vein accesses.
At the anterior aspect of the wrist, the medial nerve can be damaged directly by the needle or indirectly by a hematoma.
19.3 Central Venous Access
19.3.1 Indications
The risk of complications related the central venous catheter (CVC) insertions is higher in children than in adults. The benefit/risk balance should therefore be analyzed before every CVC placement. Indications for CVC placement in children are:
Extensive surgery with potential massive blood loss or hemodynamic instability
The need to measure the central venous pressure
Infusion of inotropes
Infusion of antibiotics or chemotherapy inducing phlebitis (osmolality >500 mOsm, pH <5 or >9)
Postoperative parenteral nutrition
Hemodialysis, plasmapheresis
Neurosurgery is a sitting position (rapid aspiration of air bubbles)
Lack of peripheral venous access
The experience of the operator and the proper use of USG can, by reducing risks, increase the benefit/risk balance and allow children to access the CVCs for broader indications.
19.3.2 General Aspects
19.3.2.1 Equipment and Technique of Insertion
Skin preparation for CVC placement should be done with chlorhexidine (>0.5 %) with alcohol in children [14]. There is however no consensus for skin disinfection in a neonate younger than 44 gestational weeks. A Seldinger insertion technique is usually used during CVCs insertion: small puncture needle, insertion of a soft metallic guide wire (GW), skin incision, dilation, and introduction of the catheter over the GW. In neonates and infants, the use of a peripheral intravenous (IV) cannula can facilitate the puncture: by having smaller and sharper inner needle tips, they limit depression of the anterior wall of the vein. Whatever the needle used, a syringe should always be connected to increase handling, avoid any blood loss, and prevent air embolism in spontaneous breathing children. In children, it is advised to insert the GW by its J-shaped end. We know however that the diameter of the J-shaped end (close to 4 mm) can exceed the diameter of an infant’s veins. Therefore, the soft straight tip can be used with precaution and under some conditions: gentle insertion without any force and ideally under fluoroscopy. Before any dilation or insertion of large-bore catheter, the correct migration of the GW into the chosen vein should be verified by US or fluoroscopy. US is also used to mobilize and redirect the GW in real time if an aberrant migration is detected (Fig. 19.17). Dilators are introduced over the GW till a “click” is felt (passage of the wall of the vein) but not further. If any resistance is felt during dilation, in-and-out movements of the GW are used to detect immediately any unintentional bending of the GW.
Fig. 19.17
Ultrasound detection and guidance of the guide wire (GW). (a) Anatomy before puncture (RBCV–LBCV right and left brachiocephalic veins, SVC superior vena cava, Ao aortic arch). (b) Migration of the GW (arrows) from the right subclavian to the LBCV. (c) Withdrawal of the GW till the J-shaped tip is seen. (d) Insertion of the GW downwards in the SVC
CVCs are in polyurethane or silicone and have single or multiple lumens. Catheters should be radiopaque and have centimeter graduations and a distal conical soft end. The size of the CVC depends on the site of insertion and the age/weight of the child (Table 19.3). The diameter of double-lumen (4 F) catheters is large compared to the veins of neonates or preterm infants and should therefore be used only if one lumen is insufficient.
Table 19.3
Size of central venous catheters used depending on the weight, age, and vein size
<1.5 kg | Newborn | 6 m–4 years | 4–10 years | >10 years | |
|---|---|---|---|---|---|
Single-lumen CVC | 2 F (22 ga) | 3 F (20 ga) | 3 F (20 ga) | 4 F (18 ga) | 5 F (16 ga) |
Double-lumen CVC | /a | 4 F | 4 F | 5 F | 7 F |
PICC | 1 F (28 ga) | 2 F (23 ga) | 3 F (vein > 3 mm) | 4 F (vein > 4 mm) | 5 F (vein > 5 mm) |
Umbilical catheters | 3.5 F | 5 F | / | / | / |
The optimal length of insertion depends on the child (age, weight, length), the approach (site, side, low or high approach), and the mediastinal anatomy (angle and length of the brachiocephalic vein). Some tables and calculation have been made, but the data over left-sided approaches are rare [15]. Whatever the insertion site, verifying the catheter tip position is mandatory.
CVCs are carefully secured to the skin with skin stitches: the goal is to avoid any catheter withdrawal or kinking without damaging the skin (loose skin stitches are used and hard plastic clips avoided) (Fig. 19.18).
Fig. 19.18
Securing central venous catheters in young children. Loose skin stitches avoid catheter withdrawal without damaging the skin. (a) Fully inserted right subclavian catheter. (b) Partially inserted left subclavian catheter; the hard plastic clip is not used to avoid excessive pressure on the skin
19.3.2.2 Complications Common to All Sites
CVC-related complications can be classified in immediate, intermediary, or late complications (Table 19.4). Specific complications linked to the access of the superior or inferior vena cava (SVC or IVC) will develop late.
Table 19.4
Classification of central venous catheter-associated complications
Common complications | ||
Immediate | Intermediary | Late |
Hemorrhage, hematoma Arterial puncture Arrhythmia Extravascular GW migration Air embolism | Tamponade Extravascular fluid infusion | Catheter occlusion Thrombosis Infection Catheter rupture Arteriovenous fistula |
Specific complications | ||
Access to the SVC | Access to the IVC | |
Pneumothorax Hemothorax Chylothorax | Peritoneal fluid infusion Perimedullar catheter migration Lower limb ischemia Portal thrombosisa | |
Immediate Complications
Arterial puncture is the most frequent complication. Consequences are hematoma, subsequently difficult or impossible punctures, respiratory difficulties, or development of an arteriovenous fistula.
Air embolism occurs mainly at the time of insertion in the spontaneously breathing child.
Extravascular GW migration is more frequent in neonates (fragility of veins and soft tissues) and/or when the GW is inserted by its straight end.
Intermediary Complications
Tamponade can have atypical presentations in children. It should be suspected in case of sudden hemodynamic deterioration after CVC placements.
Vessel perforation and extravascular fluid infusion will have consequences depending on the structure involved, the size of the hole, and the infusion rate. Repeated contact of the catheter against the vessel wall is a risk factor and should be avoided by an optimal catheter tip placement.
Late Complications
Catheter occlusion is limited by placing catheters with the lowest number of lumens required at an optimal insertion depth. Lumens are flushed with saline after every blood sample or infusion and between infusion of two incompatible medications. Positive pressure connectors are placed on any lumen that is only intermittently used. CVC occlusion is treated by instillation of alteplase, a recombinant tissue plasminogen activator, during 2 h in the occluded catheter lumen [16]. Alteplase is diluted in a volume of saline corresponding to 110 % of the priming volume of the lumen at the weight-adapted dose of:
0.5 mg till 10 kg
1 mg from 10 to 30 kg
2 mg above 30 kg
The incidence of CVC-related thrombosis is probably underestimated because the signs are often subclinical. Risk factors in children are:
Sepsis
Intracardiac surgery
Congenital thrombophilia: protein C, protein S, or antithrombin III deficiency, Factor V Leiden, hyperhomocysteinemia
Acquired thrombophilia: nephrotic syndrome, varicella, cyanogenic cardiopathy
Prolonged parenteral nutrition
The usual treatment of CVC-related thrombosis is the removal of the catheter combined with administration of heparin or fibrinolytic drugs. In some cases, the catheter can be left in place to provide local thrombolysis and avoid potential clot dislodgment.
The risk of catheter-related infection and sepsis is inversely proportional to gestational age (in neonates) and directly proportional to the duration of catheterization, the use of parenteral nutrition, or mechanical ventilation. Prevention can be divided into an optimal placement (maximal barrier precautions, low number of attempts, and limited duration for placement) and meticulous care for the catheter (sterility, limited manipulations, renewal of dressing, and infusion tubing). Routine change of CVCs after a period of time is not advised if no local or systemic infection signs can be found. Differentiation between catheter infection and contamination is often difficult: peripheral and central blood cultures and catheter tip culture may clarify the diagnostic. If fever persists despite catheter change and antibiotics, endocarditis should be excluded.
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