Peripheral venous access

Peripheral venous cannulation in pediatric cardiac patients can usually be accomplished with few complications. Ideally, a large cannula is inserted into a large vein of the arm or leg, but if this is anticipated as initially difficult, another practical approach can be adopted. A small superficial vein at any site is cannulated with a small catheter (24 or 22 gauge [ga]) before induction or during inhalation induction of anesthesia. Once the airway is secured and the patient immobile, larger‐bore venous access can be attempted. Cannula sizes appropriate for intraoperative use are selected according to the patient’s weight as follows: <3 kg, 24 ga; 3–10 kg, 22 ga; 11–20 kg, 20 ga; 21–30 kg, 18 ga; > 30 kg, 16 ga. Typical locations for peripheral venous access include tributaries of the cephalic and basilic veins and dorsal metacarpal veins at the dorsum of the hands; basilic, cephalic, and median cubital veins of the forearm; the great saphenous vein at the ankle; the dorsal venous arch of the foot; and the lateral malleolus vein of the lower extremities.

Once the patient is cannulated and in the surgical position, it is important to make sure that each intravenous (IV) line is functioning without abnormal flow resistance before draping is commenced. If flow of the infused fluid in the line is in some way affected by body position (e.g. wrist flexion or extension), cautious monitoring of the catheter during surgery is necessary to avoid extravasation. Only a large‐bore, short catheter in a large vein with flow unaffected by positional change should be used for rapid infusion of more viscous colloids or packed red blood cells [1]. Extravasation of these fluids can lead to compartment syndrome and the need for fasciotomy and permanent loss of limb function in severe cases.

Commonly selected locations for this purpose include the saphenous vein at the ankle, the cephalic or basilic vein of the forearm, and the external jugular vein (EJV). When the vein can be successfully punctured but advancement of the catheter to its full length is impossible, a spring‐wire guidewire 0.018″ (for 22 ga) or 0.015″ in size may be used to facilitate cannulation [2].

Peripheral vein cannulation in pediatric patients is not always an easy task; therefore, sufficient planning and preparation often help to overcome anticipated difficulties. One of the useful tools for prediction is the difficult intravenous access (DIVA) score, which consists of four variables to which numbered scores are assigned: three points are given for prematurity; three for age less than 1 year and one point for age 1–2 years; two points for vein not palpable; and two for vein not visible. One study has shown that the first attempt at IV line placement is unsuccessful in more than 50% of children with a DIVA score of 4 or more [3]. The DIVA score has been refined and validated, and three predictors, including history of stay in the newborn intensive care unit (ICU), operator’s inexperience, and skin color, have been incorporated [4]. Recognition of a child with a high DIVA score should warn anesthesiologists and prompt them to prepare a backup plan for anticipated difficult peripheral venous access. In the face of unanticipated DIVA, calling for the help of an experienced and skilled anesthesiologist, if available, is far more important than multiple attempts and hope for successful cannulation. Each consecutive puncture and failed cannulation increase difficulty of subsequent attempts and risk of complications.

New technologies have been developed in the past several years to facilitate venous access in children, with variable results [5–9]. Among them, ultrasound and illumination techniques are promising, particularly in children with anticipated cannulation difficulties. Ultrasound‐guided methods for peripheral IV access will be discussed in detail later in this chapter. With respect to illumination techniques, a few commercially available vein locator devices can be used. The AccuVein^® AV300 or AV400 (AccuVein Inc., Huntington, NY, USA) is a vein illumination device that operates by projecting infrared light, which is absorbed by hemoglobin, and making the veins visible through a viewfinder. The VeinViewer^® (Luminetx Corp., Memphis, TN, USA) uses near‐infrared light and projects a real‐time image of the vein pattern directly onto the patient’s skin. Neither obesity [5] nor skin color [6] interferes with vein visibility. Although the efficacy and use of these devices under routine and anticipated difficult IV access conditions have not been validated in large‐scale studies of pediatric patients, further evaluation would be beneficial because they are easy to operate, non‐invasive, and portable.

Technique. Venipuncture is simple and common for all peripheral veins. For veins of the dorsum of the hand, holding the hand in place with the wrist fully flexed while stretching the dorsum of the hand with one’s thumb and index finger makes the dorsal metacarpal veins easier to cannulate (Figure 13.1A). If the vein is visible or palpated, the puncture is straightforward. If the vein is not visible or cannot be palpated, blind insertion attempts have traditionally been made based on typical anatomic locations. However, new devices, such as the VeinViewer, may visualize the vessel and facilitate successful cannulation (Figure 13.1B, C). Even if blood flow is not observed in the cannula, it may be advanced into the vessel and cannulation can be confirmed by an infusion trial with a small amount of infusate. Lack of signs of local extravasation indicates successful cannulation.

Central venous access

Central venous access is often necessary during surgery for congenital heart defects to measure central venous pressure (CVP), deliver vasoactive drugs or high‐osmolarity solutions into the central circulation, and to repeatedly sample blood to monitor venous oxygen saturation and other metabolic parameters. To achieve these goals, multi‐lumen catheters are recommended. The largest distal lumen should be used for pressure monitoring, whereas proximal lumen(s) should be used for other purposes including administration of vasoactive medications. Because large‐size catheters in small vessels are associated with higher rates of thrombosis, the size of the catheter should be the smallest acceptable.

In patients with single‐ventricle physiology who have undergone palliative cavopulmonary anastomosis surgery, a catheter inserted via the upper limb or neck veins [10] can be used to measure pulmonary artery pressure, which may be important to assess. If access is required only for inotrope infusion, it would be prudent to insert the line elsewhere because thrombosis or occlusion of the superior vena cava (SVC) would limit pulmonary blood flow [11, 12]. Catheters inserted from below the diaphragm should reach the inferior vena cava (IVC) for accurate assessment of atrial pressure [13]. In patients with single‐ventricle physiology and adequate atrial septectomy, monitored pressure reflects systemic ventricular diastolic pressure. If complete atrial or ventricular mixing is observed, line flushing or bolus administration of drugs should be performed with care, because clots or inadvertent air infusion can result in paradoxical systemic embolism.

Percutaneous central venous access

Among various available approaches to central venous access, the percutaneous approach has become standard practice at many institutions. This has been particularly true because of the development and widespread use of portable ultrasound devices for ultrasound‐guided catheter insertion (see later). Common sites for percutaneous central venous access include the internal jugular, subclavian, and femoral veins. Various central catheters are commercially available. Recommended sizes and lengths for each insertion site are listed in Table 13.1.

Full barrier precautions are mandatory upon catheter placement. Sterile technique with gowns and wide draping should be applied during all percutaneous central cannulations to reduce the risk of catheter‐associated infection. After sterile skin preparation with chlorhexidine‐containing solution or iodine, wide draping is performed, preferably with a clear, fluid‐impermeable, adhesive and aperture drape so that the underlying anatomy is clearly visible. The Seldinger technique is the standard approach. The basic principle is to place a guidewire into the target vessel and then thread a large‐bore catheter over the guidewire. For guidewire placement, either an introducer needle or an angiocatheter (catheter‐over‐needle) may be used. The authors’ preference is to use an angiocatheter in infants weighing less than 10 kg (see Figure 13.2). In these patients, a 4 Fr central catheter is routinely used. A 0.015″ or 0.018″ guidewire should be used for cannulation. The wire is first threaded into a 24 ga catheter to enter the vessel. Using this small, 24 ga angiocatheter to puncture the vessel may minimize hematoma formation should inadvertent artery puncture occur, and reduce damage of the vessel should the needle penetrate its posterior wall. Once the catheter is placed in the vein, a short extension tube can be attached and used as a manometer to verify venous access. This verification is extremely important in patients with cyanotic lesions, because the color of blood aspirated from the catheter is not a reliable indicator of correct venous placement. One advantage of an introducer needle is that threading the outer catheter over the inner needle is not necessary. Disadvantages include the necessity to use a large needle (20 ga for a 0.018″ or 0.021″ guidewire) and the possibility of damaging the guidewire if improperly inserted, which can lead to serious complications. Because the tip of the needle may damage the structure of the thin guidewire, attention should be paid not to retract the guidewire through the needle while it is still in the vessel if there is any resistance at all; they should be removed simultaneously to avoid breaking the guidewire and a fragment being retained intravascularly. Guidewires with straight, slightly curved (angled), or J‐shaped tips are available. The shape of the tip may be one of the causes of unsuccessful threading [14], particularly in neonates or small infants. The radius of the curvature of the wire’s J‐shaped tip is often identical to or larger than the diameter of the infant’s vessel (~5 mm) [15, 16]. Our preference is to use the straight end of the guidewire in this patient population (see Figure 13.2). After the desired vein is punctured, the guidewire is carefully advanced into the SVC. The resistance to the wire’s passage should be minimal; if any resistance is encountered, the wire must be carefully withdrawn. Forcing a guidewire in the presence of resistance can lead to significant complications. The electrocardiogram (ECG) should be observed carefully as the guidewire is slowly advanced. Premature atrial contractions (PACs) are usually observed as the first guidewire‐induced dysrhythmias, signifying atrial location. If no PACs occur, the guidewire is most likely not in the atrium. Premature ventricular contractions, especially if multifocal in nature and occurring as the first observed dysrhythmia, indicate that the guidewire is probably in the ventricle and should be immediately withdrawn. Insertion of a transesophageal echocardiography (TEE) probe before attempting central venous access may facilitate visualization of the guidewire and confirmation of its correct location [17].

Patient height (cm)	Internal jugular/subclavian vein	Femoral vein
<60	20 ga, single lumen, 8 cm	20 ga, single lumen, 12 cm
	3–4 Fr, double lumen, 8 cm	3–4 Fr, double lumen 12 cm
60–80	4 Fr, double lumen, 8 cm	4 Fr, double lumen, 12 cm
80–130	4 Fr, double lumen, 12 cm	4 Fr, double lumen, 12–15 cm
130–160	5 Fr, double lumen, 12–15 cm	5 Fr, double lumen, 15 cm
160–170	7 Fr, double lumen, 15 cm	7 Fr, double lumen, 20 cm
>170	8 Fr, double lumen, 16 cm	8 Fr, double lumen 20 cm

After guidewire placement, a very small incision is made followed by careful dilation and catheter cannulation. Dilators included in prepackaged CVC kits are often one size larger than the catheters (e.g. a 5 Fr dilator for a 4 Fr catheter). This might not be optimal with small infants; passage of the catheter without dilation or use of a dilator of the same size as the catheter would be preferable. This allows for the smallest possible entry into the vein, to minimize bleeding and trauma to the vessel wall, both of which can lead to thrombosis or vascular insufficiency. In small infants, attention should be paid to blood loss during the catheterization procedure; direct compression of bleeding puncture sites with the heel of the non‐dominant hand should be applied while threading dilators or catheters. Difficult catheterization often requires more hands, and assistance should be requested accordingly. Once the catheter is advanced to the desired depth, it should be secured with sutures and dressing.

Internal jugular vein

The internal jugular vein (IJV) originates from the jugular foramen at the base of the skull. The right IJV is large and lateral to the common carotid artery (CCA) along most of its length (termed the carotid sheath) and is the most common site for central venous access in pediatric patients undergoing cardiac surgery. The IJV provides a direct route to the right atrium (RA) and is an optimal site for catheterization. In patients with supracardiac‐type total anomalous pulmonary venous return (TAPVR), the vertical vein draining blood from the common chamber to the brachiocephalic vein and the left IJV and left subclavian vein (SCV) usually contains oxygen‐rich blood. Oxygen‐rich blood can be drawn while puncturing the left IJV, and it is sometimes difficult to distinguish whether the blood is from an artery or a vein. We recommend use of a pressure transducer for confirmation. Some surgeons discourage the use of the left veins in TAPVR. The right IJV, right SCV, or femoral veins (FVs) can be used instead of the left IJV and/or SCV.

Some simulated models have shown that penetration of the posterior wall of the IJV is unavoidable [18, 19]. Inadvertent CCA puncture can occur unless its exact location is known. The CCA and IJV overlap area differs among studies from various countries and approaches [20–23]. Both the lower approach (at the junction of the two heads of the sternocleidomastoid muscle) and the higher approach (at the cricoid cartilage) provide a similar pattern of overlap (Table 13.2). The overlap between the IJV and the CCA increases with head rotation to either side [24]. In addition, the right IJV is preferred to the left because of a smaller overlap area with the CCA on the right side and its more lateral position [24]. Greater head rotation (more than 30°) to the left should be avoided, because this increases the right IJV and CCA overlap and risk of carotid puncture. Positive inspiratory pressure, but not the Trendelenburg position, can increase the cross‐sectional area of the IJV [25]. Use of combination of the Trendelenburg position, liver compression, and simulated Valsalva maneuver can effectively increase the diameter of the IJV [26]. Gentle skin traction can also improve the success rate of catheterization [27]. An anchoring maneuver using a pilot needle facilitates IJV catheterization at its entry in the majority of infants. If the pilot needle is left in the IJV, and the IV catheter (22 or 24 ga) is passed just posterior to the puncture point of the pilot needle to track the pilot needle path at a 10–20° angle to the skin, a natural tumbling movement of the pilot needle helps to anchor the anterior wall of the IJV and facilitate puncture with the catheter needle [28]. The bevel‐down approach to the right IJV may decrease the incidence of posterior venous wall damage and hematoma formation compared with the bevel‐up approach [29].

Higher approach (n = 130)	43.1%	43.8%	13.1%
Lower approach (n = 216)	35.2%	53.2%	11.6%

The CCA and IJV are at the cricoid cartilage in the higher approach and at the junction of the two heads of the sternocleidomastoid muscle in the lower approach. Schematic representation of CCA and IJV as imaged by ultrasound with operator standing at patient’s head. Results are combined from studies [19–22].

Technique. With a landmark approach, the location of the clavicle, sternocleidomastoid muscle, and cricoid cartilage should be confirmed by visually observing and palpating the neck. After disinfecting the insertion site, the skin is usually punctured midway between the mastoid process and the sternal notch in the “high” approach, at the junction of the two heads of the sternocleidomastoid muscle or at the level of the cricoid cartilage in the “middle” approach, or near the jugular notch in the “low” approach (Figure 13.3). After aspiration of dark‐colored blood from the punctured vessel, the Seldinger technique should be used for guidewire and catheter placement (described earlier). If the artery is inadvertently punctured, compress the puncture site for several minutes to ensure hemostasis. Ultrasound‐guided puncture will be discussed in detail later in the chapter.

Subclavian vein

Subclavian central venous catheterization is a relatively safe procedure, with minimal complications in pediatric patients [31–35]. The SCV is an extension of the axillary vein at the outer border of the first rib, lies under the clavicle, and runs in the subclavian groove on the first rib. The SCV joins the IJV to form the brachiocephalic vein. It lies anterior to the anterior scalene muscle, and the subclavian artery lies posterior to the anterior scalene muscle. Catheterization of the SCV has several advantages, including its relatively constant position in reference to surface landmarks in patients of all ages, comfort for the awake patient, and less tip migration and greater stability with patient movement. Disadvantages include risk of pneumothorax and the potential inability to dilate the space between the clavicle and the first rib. There is also a possibility that a subclavian catheter will enter the contralateral brachiocephalic vein or ipsilateral IJV instead of the SVC.

Technique. For right‐side subclavian venous puncture, positioning with the patient’s right upper arm abducted 0° maximizes clavicle and SCV overlap. In the 5°–10° head‐down tilt position, puncture the skin near the clavicle at the midpoint or just lateral to the clavicle. Advance the tip of the needle to contact the clavicle. The tip should then be advanced underneath the clavicle with the needle kept in the horizontal position to avoid puncturing the subclavian artery or the lung. When no blood return is obtained, withdraw the needle gently while pulling back the plug with the syringe attached to the angiocatheter. After obtaining dark‐colored blood return without pulsation, cautiously advance the guidewire and then the dilator.

External jugular vein (EJV)

The course of the EJV can be readily seen on either side of the patient’s neck. The EJV can also be used as a peripheral vein that provides rapid and easy vascular access. Inadvertent arterial puncture is extremely rare with this approach. Although the EJV is a viable site for central venous access with a low complication rate, the EJV has positional concerns because of its angle relative to entry to the SCV, which may hinder the passage of a guidewire into the SVC. This is particularly true in younger patients. Success rates of percutaneous central catheterization via the EJV vary from 54 to 90% [36–40].

Technique. With the patient’s head extended, the central portion of the EJV compressed, and the EJV stretched peripherally, puncture the skin with an angiocatheter (<10 kg, 22 ga; 10–20 kg, 20 ga; >20 kg, 18 ga) and insert a curve‐tipped guidewire after obtaining dark‐colored blood. A small incision with a 25–27 ga needle at the insertion point can aid angiocatheter insertion.

Femoral vein

Another major site of access to the central circulation is the FV. The FV is the most commonly accessed central route in pediatric patients outside the operating room (OR) because of the relatively high rate of success and low incidence of complications [41, 42]. Once thought to be associated with an increased risk of infection, studies have since concluded that cannulation of the FV is of no greater risk than other sites [43, 44]. Several studies [13] have reported that mean CVP measured in the IVC below the diaphragm is identical to that measured in the RA in patients with or without CHD (in the absence of increased intra‐abdominal pressure or IVC obstruction). Agreement of IVC and RA pressures in patients with an interrupted IVC with azygos vein continuation into the SVC, commonly seen in heterotaxy syndrome, have not been evaluated; however, the catheter can be used for other purposes such as drug or fluid infusion.

Technique. The patient should be positioned with a rolled towel placed under the hips to obtain moderate extension. The puncture site should be 1–2 cm inferior to the inguinal ligament and 0.5–1 cm medial to the femoral artery impulse, with the needle pointed toward the umbilicus. Ultrasound guidance is useful for identifying important anatomic structures to aid in successful, uncomplicated placement (see later). It is important to puncture the vessel below the inguinal ligament to minimize the risk of retroperitoneal bleeding. Once cannulated, the Seldinger technique should be used as for IJV cannulation. The tip of the catheter should be located in the mid‐IVC.

Tunneled percutaneous or intracardiac lines

In patients with difficult venous access and an anticipated prolonged postoperative course, a tunneled silicone catheter may be used to ensure long‐term central venous access. Hickman and Broviac are brands of single‐ and double‐lumen catheters that provide external access. These catheters can be placed percutaneously in standard fashion as mentioned in the previous section, or placed transthoracically into the SVC or RA, as with a standard transthoracic catheter but with a subcutaneous tunnel separating the skin exit several centimeters from the chest wall entry site. Compared with standard polyurethane transthoracic catheters, these catheters preserve other access sites for possible future interventions and are less thrombogenic.

Ascertainment of correct position of upper body central catheters

Proper placement of CVCs is necessary to prevent complications and to provide accurate CVP measurements. Some experts recommend that the CVC tip should be in the SVC, above the pericardial reflection, to make sure that it is located outside the pericardium. This will minimize the risk of cardiac tamponade should perforation occur. If the CVC tip is located in the more proximal SVC, the risk of thrombosis increases, and the catheter could migrate into other vessels such as the azygos vein, where pressure monitoring will no longer represent CVP. Others recommend that the CVC tip be positioned in the SVC, just above the SVC–RA junction. This will reduce the risk of thrombosis, malposition, and tip perforation and increase the longevity of the catheter. Various methods have been proposed to determine proper placement and will be discussed below. In the OR setting, TEE‐guided catheter tip positioning is a reliable and safe method and thus can be considered the gold standard [17].

Echocardiography

Transesophageal echocardiography is used for many congenital heart operations. Catheter tips and guidewires are easily imaged with TEE, and one study using TEE‐guided CVC placement demonstrated a 100% success rate for correct placement in the SVC when TEE was used, as compared with 86% when surface anatomical landmarks were used in infants and children undergoing congenital heart surgery [17]. The TEE probe is placed before CVC attempts are made, and the SVC–RA junction in the 90° plane is imaged. When the vessel is punctured and the guidewire passed, it should be visualized passing from the SVC into the RA. Then the catheter is passed to its full length, the guidewire removed, and the tip of the CVC identified. Flushing the CVC with saline creates an easily visible stream of contrast which identifies the tip. The CVC is then pulled back until it is above the RA, in the distal SVC 1–2 cm above the crista terminalis. Using this technique, immediate, accurate confirmation of placement is obtained before final securing, and before the surgery. The proximal SVC, which is more than 2 cm above the RA, is difficult to image using TEE, so this method is most accurate in placing CVC in the distal SVC. Also, the commonly accepted radiographic SVC–RA junction is often higher than the SVC–RA junction noted by TEE [17].

Transthoracic echocardiography can also be utilized for SVC catheter placement. Park et al. reported 106 right IJV catheter placements in 2‐ to 12‐month‐old infants undergoing cardiac surgery [52]. TTE was 96.2% successful at identifying the crista terminalis and allowing placement of the CVC tip within 10 mm above this structure. A 4–10 MHz wide band linear echo probe with standard cardiac ultrasound machine was used in transverse plane at the right second, third or fourth intercostal space. Cross‐sectional images of the ascending aorta, PA, and SVC were obtained, and then the probe was rotated 90° clockwise to obtain images of the SVC–RA junction. The catheter tip was advanced to the desired location, with saline flush aiding in identifying the tip. Two‐thirds of the catheters could be visualized using the longitudinal view; the others could be visualized using the transverse short axis view with the catheter identified as a white dot in the SVC, and placed at the level of the PA bifurcation.

Radiography

The chest radiograph is still considered the gold standard to confirm proper placement of the catheter [53]; however, post‐insertion chest radiography before surgical incision merely to confirm placement of the catheter tip may not be justified in the OR in terms of time, cost, and radiation exposure to the patient. A chest radiograph should be routinely obtained immediately after surgery to reconfirm catheter tip location; the catheter tip should be seen in the area from the level of the first rib to above the pericardial reflection. Based on studies on embalmed and fresh cadavers, the carina is an easily recognizable radiographic landmark in pediatric patients and can be used to confirm that the catheter tip is outside the cardiac chamber [54]. The caveat is that the commonly accepted radiographic SVC–RA junction is often higher than that noted by TEE [55]. Therefore, the catheter tip located within the atrial silhouette on the chest radiograph can be outside the atrium as documented by TEE. Furthermore, an SVC catheter directed posteriorly down the azygos vein may not be detected by anteroposterior chest radiography alone.

Electrocardiographically guided placement

Intravascular ECG may be used in children to guide correct CVC placement [56, 57]. A normal or hyperosmolar (3%) saline‐filled lumen with a special ECG adaptor or a guidewire within the lumen attached to a sterile alligator clip serves as an exploratory electrocardiographic electrode. Prepackaged CVC sets are commercially available to allow intracardiac ECG monitoring [58]. A sudden increase in P‐wave size (P atriale) occurs as the catheter enters the RA. The catheter tip can then be pulled back 1–2 cm to the desired position within the SVC. Because this method requires special equipment not always available in the OR, TEE can be used as a sufficient substitute.

Height‐ and weight‐based formulae

In the absence of TEE guidance or intravascular ECG, CVC tip position may not be confirmed until postoperative chest radiography, allowing for any potential malpositioning to persist undetected. One study proposed formulae to predict the depth of CVC insertion, with the aim of preventing inadvertent catheter tip placement in the RA [30]. Using a large database of CVC placement data in children, the following formulas were developed for catheter insertion via the right IJV or SCV, with the targeted location of the catheter tip at the radiographically determined SVC–RA junction:

The authors also provided a weight‐based formula for length of CVC insertion via the right IJV or SCV. Use of these formulae should result in CVC placement in the mid‐SVC in more than 95% of patients. Caveats of these simplified formulae are that for the IJV, the puncture site is high, precisely midway between the mastoid process and the sternal notch. For the SCV, the puncture site is 1–2 cm lateral to the clavicle midpoint. The formulae must be adjusted if different puncture sites are desired. In addition, the formulae were developed for targeting of the catheter tip to the radiographic SVC–RA junction. As mentioned earlier, the radiographic SVC–RA junction is usually higher than the TEE‐confirmed SVC–RA junction. A more recent study [53] used a smaller number of pediatric patients to provide height‐based formulae for determining the depth of the right internal jugular catheter (Table 13.3). They used TEE or intracardiac ECG to precisely guide the catheter tip to slightly above the SVC–RA junction and measured the depth of the CVC at the site of right internal jugular catheterization. The formulas listed here have not been validated for accuracy in a prospective fashion and therefore should be used with caution.

	Andropoulos et al. [30]	Yoon et al. [53]
Formula	(Ht/10 − 1) cm if Ht ≤ 100 (Ht/10 − 2) cm if Ht > 100	(0.07 × Ht) + 1.7
Ht (cm)	IJV/SCV	IJV
40	3.0	4.5
50	4.0	5.2
60	5.0	5.9
70	6.0	6.6
80	7.0	7.3
90	8.0	8.0
100	8.0	8.7
110	9.0	9.4
120	10.0	10.1
130	11.0	10.8
140	12.0	11.5
150	13.0	–
160	14.0	–
170	15.0	–

Ht, height; IJV, internal jugular vein; SCV, subclavian vein.

In two‐lumen catheters, the second orifice is usually at 1.5–2 cm from the tip of the catheter. Catheters should be placed more than 4.5–5 cm from the skin. Insertion points differ among patients, especially in the IJV; thus, it is necessary to adjust 0.5–1 cm from the standard lengths.

Peripherally (percutaneously) inserted central catheters

Given its safety and reliability as a method to efficiently obtain central access, the peripherally inserted central catheter (PICC) has emerged as a favorable percutaneously inserted central line in pediatric patients with acute or chronic illness. The PICC line is a thin, soft, and long catheter that can be used for long‐term IV antibiotics, nutrition or medications, and blood draws. In use for more than a decade [59], PICCs are routinely used in newborns expected to require prolonged venous access. The complication rate for these catheters is very low [60, 61], and they are generally easy to insert into the central circulation via the antecubital, saphenous, hand, axillary, or wrist veins. Because of the increased popularity of PICCs for IV access in children, many institutions have adopted a team approach for pediatric PICC placement. Most important for successful placement is early access, before the large, visible, superficial veins are exposed to injury from attempts at peripheral IV placement. In critically ill newborns with CHD, it is best to insert a PICC line soon after hospital admission. Commercially available PICCs are 1–5 Fr, single or double lumen, 6–65 cm, and made from polyurethane or silicone. For a newborn, a 2 or 3 Fr PICC line is often used [62]. Centrally delivered medications or fluids are administered through a PICC line; however, these are often inadequate as the sole pre‐bypass access for cardiac surgery. Despite the primary intention of PICCs to be placed centrally, only half are successful; however, non‐centrally (mid‐clavicle and more distal) placed PICCs can still be used safely and reliably for the administration of medications and isotonic fluids. Insertion of PICCs should follow the techniques described for peripheral venous access and central line insertions.

Radial artery

This is the most commonly accessible location for initial arterial cannulation in most infants and children. Before cannulation, the Allen’s test can be considered to verify sufficient collateral ulnar circulation [64]. Cannulation ipsilateral to an existing or planned systemic‐to‐PA shunt should be avoided.

Technique. Secure the patient’s hand gently to an armboard, with the wrist slightly dorsiflexed and with a small roll underneath it (Figure 13.4). Prepare the skin with antiseptic solution. Use palpation to identify the artery. Alternatively, audio Doppler or ultrasound guidance can be helpful if the pulse is weak. Lighter anesthesia during catheterization may provide a stronger pulse and increase the success rate. Use a 24 or 22 ga angiocatheter flushed with heparinized saline to optimize the flow of blood into the needle hub. The first attempt offers the greatest chance of success; therefore, conditions, such as lighting, positioning, and vessel identification should be optimized. Puncture of the artery is indicated by brisk flashback. Advance the needle and catheter 1–2 mm into the artery to ensure intraluminal placement and attempt to thread the catheter over the needle its full length into the artery. Alternatively, the artery can be transfixed, the needle pulled back, and the cannula gently withdrawn until brisk flashback is observed (Figure 13.4D). The cannula can then be advanced into the artery (Figure 13.4F, G) or a small 0.015″ intravascular guidewire can be inserted into the artery and the cannula advanced over the wire. Either way, minimal resistance signifies successful threading. If the first attempt is unsuccessful, additional attempts can be made at the same site or slightly proximal to it, to avoid areas of arterial spasm, thrombosis, or dissection. Circulation distal to the catheter should be determined by inspection of the color and capillary refilling time of the fingertips and nailbeds and pulse quality as determined by pulse oximetry. We recommend that the catheter be secured with clear adhesive dressing and tape, to ensure that the insertion site and catheter hub are visible.

Femoral artery

The common or superficial femoral artery is large and easily accessible in most patients and is a logical choice when radial arterial access is not available. Our practice is to avoid the femoral artery for prolonged catheterization, when alternative sites are available, because of potential vascular damage of the involved leg. However, if the patient experiences extreme hypotension or peripheral vasoconstriction when no other major vessels are easily palpable, the femoral artery may represent the only viable choice for arterial catheterization. Left‐sided femoral artery catheterization is preferred if future cardiac catheterization is anticipated.

Technique. Place a small towel under the patient’s hips to extend the leg slightly to a neutral position. Positioning can be aided by slight external rotation with the knees restrained by taping to the bed. After sterile preparation and draping, palpate the course of the superficial femoral artery and puncture the vessel 1–2 cm inferior to the inguinal ligament to avoid puncturing the artery above the pelvic brim, where a retroperitoneal hematoma could form. Audio Doppler or ultrasound can be used to identify the course of the vessel if the pulse is weak. Various puncture techniques are available: direct puncture with an angiocatheter; an introducer needle supplied with a commercially prepackaged kit; or a 21 ga butterfly needle with the extension tube removed. The needles should be flushed with heparinized saline to increase flashback. Use a small, flexible, 0.015″ or 0.018″ guidewire. Threading a polyethylene catheter over the guidewire can often be done without making a skin incision. Importantly, a dilator should not be used because it could cause arterial spasm, dissection, or bleeding if the puncture site is large. Secure the catheter by suturing around the entry site and suturing wings around the hub. Distal perfusion should be assessed immediately, and a pulse oximetry probe should be placed on the foot for continuous monitoring and early warning of poor arterial perfusion.

Brachial artery

The brachial artery has been used successfully as an arterial access site in neonates and small children [65]. However, this site may have theoretical concerns because it has poor collateral circulation compared with the radial, femoral, and axillary arteries, though this has not been proved by any studies to date. The present consensus is that the brachial artery should be reserved for situations when other options are limited, for example, when a right upper‐extremity arterial line is necessary to monitor pressure during cross‐clamping for repair of coarctation of the aorta, CPB for aortic arch hypoplasia, or interruption.

Technique. A 24 ga catheter should be used in patients weighing less than 5 kg. Restrain the arm in a neutral position on an armboard, and identify the arterial pulse above the elbow crease, above the bifurcation into the radial and ulnar arteries. The method of cannulation is the same as for radial arterial catheterization. Again, distal perfusion should be monitored continuously by pulse oximetry. The catheter should be replaced postoperatively with a catheter at a site that has better collateral circulation as soon as possible.

Axillary artery

The axillary artery is large and well collateralized. Several studies have shown this artery to be a viable option for critically ill children when other sites are not accessible [66–68]. In addition, the complication rate is low. However, given the potential for arm and hand ischemia and intrathoracic bleeding, the axillary artery should be a site of last resort when other options are not available.

Technique. Abduct the arm 90° and extend it slightly at the shoulder. Palpate the artery high in the axilla, puncture with an angiocatheter, and exchange over a guidewire for a longer catheter. A short catheter may be pulled out of the vessel with shoulder extension. Therefore, longer catheters (e.g., 5 cm) are recommended. As with the brachial artery, distal perfusion should be assessed and carefully monitored for potential upper‐extremity ischemia. Catheter tip position located outside the first rib should also be confirmed by chest radiography. Because the axillary artery is close to the brachiocephalic artery, it is imperative to flush the catheter gently by hand after blood draws, thereby preventing air bubbles or clots from being introduced into the circulation and minimizing the risk of retrograde cerebral embolization.

Umbilical artery

The umbilical artery can be cannulated in a newborn during the first 72 hours of life and is the site of choice in newborns requiring surgery within a week after birth. Umbilical artery catheterization entails potential risks regardless of the position of the catheter; placement of the catheter with its tip at the seventh to eighth thoracic segment may be associated with fewer complications than placement at lower positions [69, 70]. Umbilical arterial lines have an uncertain link with necrotizing enterocolitis. A neonate with ductus‐dependent circulation, low diastolic pressure, and subsequent systemic steal can be at increased risk of this complication. Umbilical catheters are generally inserted in the delivery room or in the neonatal ICU shortly after birth. Lower‐extremity emboli, vascular insufficiency, and renal artery thrombosis have been reported with this site; however, the overall risk is low, and the site is highly desirable because it is a large central artery, which allows for accurate pressure monitoring throughout surgery, while preserving other sites for potential future arterial access.

Technique. Prepare the umbilical stump in a sterile manner and transect. Two small muscular‐walled arteries and a larger thin‐walled vein are easily identified on the umbilical cord cutoff. Insert a 3.5 Fr catheter blindly into the artery after dilating the vessel. The catheter tip should be placed at the level of the diaphragm or low in the descending aorta, and its position should be confirmed radiographically as soon as possible.

Temporal artery

The superficial temporal artery was widely used, particularly in premature babies. However, it is now avoided because of potentially severe cerebral thromboembolic complications [71, 72]. The exception is when brachiocephalic pressure must be measured during surgery for an aberrant subclavian artery (e.g., corrections for coarctation of the aorta, aortic arch interruption or hypoplasia with an aberrant right subclavian artery arising distal to the obstruction); the only way to measure pressure during cross‐clamping or bypass is via direct aortic pressure. This site should be used only during surgery, and the catheter must be removed immediately after operation.

Technique. Use a 24 ga catheter for newborns. Palpate the artery just anterosuperior to the tragus of the ear, just superior to the zygomatic arch. The artery should be approached with a very superficial approach angle (e.g., 10°–15°). Cannulation is performed in the same manner as with the radial artery.

Dorsalis pedis/posterior tibial arteries

Peripheral vasoconstriction and vasomotor instability during the early post‐CPB period make the superficial arteries in the lower extremities less suitable as sites for arterial cannulation than the radial artery. An accurate arterial pressure waveform cannot be obtained during the early post‐bypass period. These arteries may be indicated for non‐bypass surgeries or for continuous pressure monitoring in the ICU.

Technique. For the dorsalis pedis artery, position the foot in slight plantar flexion to straighten the course of the artery, which can be palpated between the second and third metatarsals. For the posterior tibial artery, dorsiflex the foot to expose the artery between the medial malleolus and Achilles tendon. The artery is often deep to the puncture site and may require a steeper puncture angle. Fix the patient’s ankle with the arterial line to a board (3) so that the line is not accidentally removed as it is covered by surgical drapes (Figure 13.5).

Ulnar artery

The ulnar artery is only considered when attempts with the radial artery have been unsuccessful or the vessel has thrombosed due to past interventions. It should be used as the last resort, when other options are not available. There is a high risk of ischemia of the hand if both radial and ulnar artery perfusions are severely compromised. However, one study of 18 ulnar artery catheters in a pediatric ICU reported an ischemia rate of 5.6%, no different from those associated with radial and femoral artery catheters [73].

Arterial cutdown

Cutdown of the radial artery is a reliable and efficient method for establishing arterial access during congenital heart surgery. This method is used as the first and primary method of securing arterial access in some institutions, whereas others only resort to it when all other attempts fail. Despite the speed and ease of access for cutdown, the existing literature indicates that a percutaneous approach is favorable to cutdown in terms of complications (e.g., bleeding, infection, failure, distal ischemia, long‐term vessel occlusion).

Technique. Position the arm as for percutaneous radial catheterization. After preparation and draping for surgery, make an incision at the proximal wrist crease, between the styloid process and the flexor carpi radialis tendon. Isolate the exposed artery with a heavy silk suture, vessel loop, or right‐angle forceps. It is no longer considered necessary to ligate the artery distally to prevent bleeding; the artery can remain patent after cutdown if not distally ligated. The simplest technique is to directly cannulate the exposed artery with an angiocatheter, in the same manner as for placement of a percutaneous radial artery catheter. Suture the catheter to the skin at its hub and close the incision with nylon sutures on either side of the catheter. To remove, cut the suture at the hub of the catheter, remove the catheter, and apply pressure for a few minutes until bleeding stops. The remaining skin sutures can be removed later.