Venous cannulation is the most common procedure performed in a pediatric hospital. It is indicated for administering therapeutic drugs and intravenous fluids to the infant or child for whom oral therapy is inadequate or contraindicated. In infants, favored sites for placing peripheral intravenous lines include scalp, external jugular, hand, antecubital, foot, and saphenous veins. In older children and adolescents, catheter placement in the lower extremities generally is avoided so that ambulation is not hindered. In infants, 22- and 24-gauge catheters are large enough for most purposes. Larger-bore catheters are used in children and adolescents. Care should be taken not to compromise the patient’s airway when restricting patient movements during the placement of scalp or external jugular catheters. Preparation of the site is dictated by the patient’s immune status and the purpose for the placement of the peripheral catheter. If the patient is immunocompromised or the catheter is needed for the administration of total parenteral nutrition fluids, site preparation should include swabbing with a povidone-iodine solution or other antiseptic that is allowed to air dry. For the routine short-term administration of fluids and medications, or when emergency venous access is required, preparation of the skin with denatured alcohol is considered adequate. The dressing should not impede inspection of the cannula and the surrounding area. In children with right-to-left intracardiac shunts, intravenous lines ordinarily are equipped with microfilters inserted distally to all administered fluids, to reduce the risk of systemic air and particulate matter embolization.

Hypertonic medications and solutions should not be given through peripheral catheters. However, if the emergency administration of hypertonic medications is absolutely necessary, and a central venous line access is unavailable, the peripheral catheter can be used. In such situations, the peripheral catheter should flush easily, and the skin must be observed for any evidence of extravasation over the catheter site. Peripheral catheters used to deliver hypertonic drugs or solutions should be replaced by central venous access, when feasible, to avoid the risk of a subsequent occurrence of extravasation. In situations in which an adrenergic agonist extravasates, subcutaneous dilute phentolamine mesylate is injected into the site through the extravasated catheter and to the leading edges of the extravasation. Risks associated with peripheral venous catheter placement are related to the patient’s underlying illness, to difficulty in making the insertion, and to the duration of cannulation. A patient with an underlying coagulopathy is at risk for the formation of a hematoma, which can be life-threatening. Such a case could occur after jugular venous punctures, with the development of a hematoma in the neck, which could impinge on the airway. Sepsis can occur from peripheral venous catheters; this complication is seen more commonly in children who are immunocompromised or have an untreated systemic infection before the catheter is placed. Catheter-related infections can be reduced if the catheter is removed when it no longer is needed medically or when the site is erythematous or tender. In many infants and children, the need for a peripheral catheter can be longer than 2 or 3 days and, therefore, the catheter should be inserted in a sterile fashion, and meticulous attention should be paid to the site.

Arterial catheter placement is used in the neonatal and pediatric intensive care units (ICUs) for continuous systemic blood pressure monitoring and arterial blood gas sampling. The most frequent indications are labile blood pressure and hemodynamic instability and for frequent monitoring of gas exchange in children with respiratory insufficiency or failure.

One should avoid cannulating an artery in a limb that has a compromised arterial supply. Examples include limbs affected
by arteritis, coarctation of the aorta, or previous arterial cutdowns and any arm that has had a classic Blalock-Taussig shunt on the same side. The preferred sites of arterial cannulation in newborns are the umbilical and radial arteries. In children, the radial, posterior tibial, and dorsalis pedis arteries are used because of the collateral circulation supplied by the ulnar, dorsalis pedis, and posterior tibial arteries, respectively. The femoral artery is an alternative site used in children and adolescents. The brachial artery has limited collateral circulation and is used only in those situations in which other sites are not available. Any limb that has an arterial catheter in place should be observed for evidence of compromised arterial supply, with extra attention given to an arm with a brachial arterial line. Catheters are inserted using a sterile percutaneous or direct cutdown technique; the percutaneous technique is used most frequently. To decrease the obstruction of arterial blood flow by the catheter itself, the smallest-bore catheter that allows easy sampling and gives a good pressure waveform is used. A 24-gauge cannula is adequate in the extremities of premature infants, a 22-gauge cannula in full-term infants, and a 20-gauge catheter in children weighing more than 10 kg.

The placement of central venous lines (CVLs) is indicated for the management of hypovolemic shock, septic shock, and myocardial failure or cardiogenic shock. Other indications are for the administration of hypertonic solutions or drugs such as 3% normal saline solution, mannitol, calcium chloride infusions, total parenteral nutrition fluids, and inotropic agents. Also, a CVL usually is used for placing a transvenous pacing wire within the heart. The placement of CVLs also may be needed in those children in whom peripheral access is impossible to obtain.