Central venous lines are essential tools in the care of complicated patients, both on inpatient wards and in the emergency department and intensive care unit. They may provide access for phlebotomy, facilitate central administration of fluids and medications, and allow direct measurement of cardiac filling pressures. Unfortunately, central lines are associated with serious complications, including nosocomial bloodstream infections. Recent data suggest that of the more than 200,000 such infections each year, 90% are due to central lines. One can minimize patient risk by practicing proper sterile technique during line insertion, maintaining adequate occlusive dressings, and removing all unnecessary lines as soon as possible. The three main approaches used to place central lines are the internal jugular, subclavian, and femoral. Watch the femoral way here http://youtu.be/ybCpeb2E0dU ANATOMY Internal jugular vein The internal jugular vein is not visible or palpable, and thorough understanding of its anatomy is crucial for successful completion of the procedure. The internal jugular exits the skull at the jugular foramen, anteromedial to the mastoid. It courses inferiorly between the two heads of the sternocleidomastoid (SCM) muscle and joins the subclavian vein medial to the head of the clavicle.3 The internal jugular may be as large as 2.5 cm in diameter distal to the cricoid ring.4 However, its size may vary because it is a distensible vessel; the vessel may partially collapse if the patient is hypovolemic, but it will also distend if the patient is placed in the Trendelenburg position.3,4 The internal jugular vein travels with the carotid artery and vagus nerve in the carotid sheath. The internal jugular always lies anterior and lateral to the carotid artery, thus making palpation of the carotid artery essential in determining the location of the vein. The right internal jugular is preferable to the left because it lies almost directly above the SVC and provides direct access to the heart should transvenous pacing or pulmonary artery catheterization be required. In addition, cannulation of the right internal jugular is more ergonomic for right-handed clinicians. INDICATIONS -Administration of agents into the central vasculature Central venous access is required to administer certain medications, including most vasoactive and/or inotropic agents (i.e., vasopressors such as dopamine and norepinephrine). In addition to expediting delivery of these drugs to the heart and arterial system, central administration decreases the risk of damaging peripheral tissue from the vasoconstrictive effects of the medications. Patients requiring total parenteral nutrition also require central access because the osmolarity of the mixture exceeds what can safely be administered into the peripheral circulation. Other hyperosmolar agents that are optimally infused through a central line include concentrated potassium solutions, hypertonic saline solutions, certain chemotherapeutic agents, and calcium chloride. Central circulation and intracardiac access Measurement of central venous filling pressure within the right atrium can be helpful in determining the volume status of a patient and can readily be transduced via a central venous catheter in the internal jugular or subclavian position. Specialized pulmonary artery (i.e., Swan-Ganz) catheters can be used to measure pulmonary capillary wedge pressure, a means of approximating left-sided filling pressure. Blood drawn from a central catheter can allow the measurement of mixed venous (or central venous) oxygen saturation, often used to estimate cardiac output. Temporary transvenous pacemakers can be inserted through central venous catheters (more specifically, sheath introducer catheters) to provide a more reliable and comfortable means of pacing than the transcutaneous route. Maintenance of venous access In acutely unstable patients, peripheral venous access may be inadequate. Patients requiring multiple medications in drip formulation can quickly run out of access points. This problem is compounded in a chronically ill patient, who oftentimes has insufficient peripheral access because of frequent blood draws and peripheral intravenous (IV) line placement. Central venous catheters provide reliable access for drawing blood and administering medication until either peripheral access can be obtained or less venous access is required. Hemodialysis and plasmapheresis Emergency or short-term dialysis and plasmapheresis can be performed via special central venous catheters (e.g., Quinton catheter).

• published: 07 Oct 2013
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