Recognizing the Correct Placement of Lines and Tubes

Chapter 10 Recognizing the Correct Placement of Lines and Tubes

Critical Care Radiology

image Patients in the critical or intensive care units (ICU) are monitored on a frequent basis with portable chest radiography both to check on the position of their multiple assistive devices and to assess their cardiopulmonary status.
• Diseases commonly seen in critically ill patients are discussed in other chapters (Table 10-1).
image In this chapter, you’ll get practical advice for evaluating the successful (or not so successful) insertion and ultimate position of multiple tubes, lines, catheters, and other supportive apparatus used in the ICU.
image Most times, a conventional radiograph is obtained after the insertion or attempted insertion of one of these devices to check on its position and to rule out any unintended complications.
image Therefore, for each tube or device, you’ll learn:
• Why they are used.
• Where they belong when properly placed.
• Where such devices can be malpositioned and what complications may occur from the device.

TABLE 10-1 COMMON DISEASES IN CRITICALLY ILL PATIENTS

Finding or Disease Discussed in
Adult respiratory distress syndrome Chapter 9
Aspiration Chapter 7
Atelectasis Chapter 5
Congestive heart failure (pulmonary edema) Chapter 9
Pleural effusion Chapter 6
Pneumomediastinum Chapter 8
Pneumonia Chapter 7
Pneumothorax Chapter 8
Pulmonary thromboembolic disease Chapter 12

Endotracheal and Tracheostomy Tubes

Endotracheal Tubes (ETT)

image Why they are used
• Assist ventilation
• Isolate the trachea to permit control of the airway
• Prevent gastric distension
• Provide a direct route for suctioning
• Administer medications
image Correct placement of an ETT (Box 10-1)
• Endotracheal tubes are usually wide-bore tubes (about 1 cm) with a radioopaque marker stripe and no side holes. The tip is frequently diagonally shaped.
• With the patient’s head in the neutral position (i.e., bottom of mandible is at the level of C5-C6), the tip of ETT should be 3-5 cm from the carina.
• This is roughly half the distance between the medial ends of clavicles and the carina (Fig. 10-1).
• Ideally the diameter of the ETT should be one half to two thirds the width of the trachea.
• An inflated cuff (balloon), if present, may fill—but shouldn’t distend—the lumen of the trachea (Fig. 10-2).

Box 10-1 Endotracheal Tubes

The tip should be about 3-5 cm above the carina.
The inflated cuff should not distend the lumen of the trachea.
They are most commonly malpositioned in the right main or right lower lobe bronchi.
If positioned with their tip in the neck, damage to vocal cords can occur.
image

Figure 10-1 Endotracheal tube in satisfactory position.

Endotracheal tubes are usually wide-bore tubes (about 1 cm) with a radioopaque marker stripe (solid white arrow) and no side holes. The tip is frequently diagonally angled (dotted black arrow). With the patient’s head in the neutral position, the tip of ETT should be 3-5 cm from the carina (solid black arrow), which is roughly half the distance between the medial ends of clavicles (dotted white arrows) and the carina.

image

Figure 10-2 Endotracheal tube with cuff overinflated.

Ideally the diameter of the endotracheal tube (solid black arrow) should be one third to one half the width of trachea. An inflated cuff (balloon), if present, may fill—but shouldn’t distend—the lumen of the trachea. Here the inflated balloon (solid white arrows) is wider than the diameter of the trachea and was subsequently deflated. Prolonged compression on the tracheal wall by an overinflated cuff can result in necrosis of the wall and tracheal stenosis.

imageHow to find the carina on a frontal chest radiograph

• Follow the right or left main bronchus backward until it meets the opposite main bronchus. The carina projects over the T5, T6, or T7 vertebral bodies in 95% of people.
• Movement of tip with flexion and extension
• Neck flexion may cause 2 cm of descent of the tube tip. This is why the tip should be 3-5 cm from the carina.
• Neck extension from neutral may cause 2 cm of ascent of the tip.
image Incorrect placement and complications of an ETT
• Most common malposition: because of the shallower angle and wider diameter of the right main bronchus or bronchus intermedius, the tip of the ETT will tend to slide into the right-sided bronchial tree preferentially to the left.
• This can lead to atelectasis (especially of the nonaerated right upper lobe and left lung) (see Fig. 5-13).
• Intubation of the right main bronchus could also lead to a right-sided tension pneumothorax.
• Inadvertent esophageal intubation will produce a grossly dilated stomach.
• The tip of the tube should not be positioned in the larynx or pharynx—the tip should be at least 3 cm distal to level of vocal cords; otherwise, the tube can damage the vocal cords or lead to aspiration (Fig. 10-3).
image

Figure 10-3 Endotracheal tube too high.

The tip of the tube (solid white arrow) should not be positioned in the larynx or pharynx. The tip should be at least 3 cm distal to the level of the vocal cords so that damage to the vocal cords and aspiration do not occur. The medial ends of the clavicles are marked by the solid black arrows.

Tracheostomy Tubes

image Why they are used
• In patients with airway obstruction at or above level of larynx
• In respiratory failure requiring long-term intubation (>21 days)
• For airway obstruction during sleep apnea
• When paralysis of the muscles affects swallowing or respiration
image Correct placement of a tracheostomy tube (Box 10-2)
• The tip should be about halfway between the stoma in which the tracheostomy tube was inserted and the carina. This is usually around the level of T3 (Fig. 10-4).
• Unlike an ETT, the placement of the tip of a tracheostomy tube is not affected by flexion and extension of the head.
• The width of the tracheostomy tube should be about two thirds the width of trachea.
image Incorrect placement and complications of a tracheostomy tube
• Immediately after insertion, look for signs of inadvertent perforation of the trachea, such as:
• Pneumomediastinum
• Pneumothorax
• Subcutaneous emphysema
• If the tracheostomy tube is equipped with a cuff, the cuff should generally be inflated to a diameter that fills but does not distend the normal tracheal contour.
• Long-term complication of tracheostomies:
• Tracheal stenosis is the most common late-occurring complication of a tracheostomy tube and can occur at the entrance stoma, level of the cuff, or at the tip of tube, but is most common at the stoma.

Box 10-2 Tracheostomy Tubes

The tip should be halfway between the entrance stoma and the carina.
If so equipped, the cuff is generally not inflated to a size greater than the tracheal lumen.
Short-term complications may include perforation of trachea.
Tracheal stenosis is the most common long-term complication, usually at the site of the entrance stoma.
image

Figure 10-4 Tracheostomy tube in correct position.

The tip (solid black arrow) should be about halfway between the stoma in which the tracheostomy tube was inserted (dotted white arrow) and the carina (solid white arrow). This is usually around the level of T3. Unlike the tip of an endotracheal tube, the placement of the tip of a tracheostomy tube is not affected by flexion and extension of the neck.

Intravascular Catheters

Central Venous Catheters (CVC)

image Why they are used
• For venous access to instill chemotherapeutic and hyperosmolar agents not suitable for peripheral venous administration
• Measurement of central venous pressure
• To maintain and monitor intravascular blood volume
image Correct placement of CVCs (Box 10-3)
• CVCs are small (3 mm) and uniformly opaque without a marker stripe.
• They are usually inserted either by the subclavian or internal jugular route. The internal jugular veins join the subclavian veins to form the brachiocephalic (innominate) veins, which, in turn, drain into the superior vena cava. The junctions of the subclavian and brachiocephalic veins generally occur posterior to the medial ends of the clavicles.
• A CVC should reach the medial end of clavicle before descending, and its tip should lie medial to the anterior end of the 1st rib.
• The catheter should descend lateral to the spine, and the tip should lie in the superior vena cava (Fig. 10-5).
• You should be able to recognize the indentation of the cardiac contour that marks the junction between the superior vena cava and the right atrium (see Fig. 2-1).
• All bends in the catheter should be smooth curves, not sharp kinks.
image Incorrect placement and complications of CVCs
• CVCs, more frequently those placed by the subclavian route, can be malpositioned.
• They are most often malpositioned with their tips in the right atrium or internal jugular vein (if inserted via the subclavian vein) (Fig. 10-6).
• In the right atrium, they can produce cardiac arrhythmias.
• When CVCs are malpositioned, they may provide inaccurate central venous pressure readings.
• Pneumothorax can occur in up to 5% of CVC insertions, more often with the subclavian approach than the internal jugular route.
• Occasionally CVCs may perforate the vein and lie outside of the blood vessel. Look for sharp bends in the catheter as a clue to a possible perforation.
• Sometimes, they may be inadvertently inserted in the subclavian artery rather than the subclavian vein.
• Suspect arterial placement if the flow is pulsatile and the course of the catheter parallels the aortic arch or fails to descend to the right of the spine (Fig. 10-7).

Box 10-3 Central Venous Catheters

The tip should lie in the superior vena cava.
All bends in the catheter should be smooth curves, not sharp kinks.
Most common malpositions are in the right atrium and internal jugular vein (for subclavian inserted catheters).
Always check for pneumothorax after successful or unsuccessful insertion attempt.
image

Figure 10-5 Subclavian central venous catheter in correct position.

Central venous catheters are small (3 mm) and uniformly opaque without a marker stripe (solid white arrow). The subclavian vein joins the brachiocephalic vein behind the medial end of the clavicle. A central venous catheter should reach the medial end of the clavicle (dotted black arrow) before descending. The catheter should descend to the right of the thoracic spine, and the tip should be in the superior vena cava (solid black arrow).

image

Figure 10-6 Central venous catheter malpositioned in internal jugular vein.

Central venous catheters, especially those placed by the subclavian route (dotted white arrow), are often malpositioned. They are most often malpositioned with their tips in the right atrium or internal jugular vein (solid white arrow). In the right atrium, they can produce cardiac arrhythmias. When central venous catheters are malpositioned, they may provide inaccurate central venous pressure measurements.

image

Figure 10-7 Arterial placement of central venous catheter.

Sometimes central lines may be inadvertently inserted in the subclavian artery rather than the subclavian vein. This catheter does not reach the medial end of the clavicle (dotted white arrow) before descending, and its tip (black circle) is oriented over the spine, directed away from the superior vena cava (solid white arrow). Suspect arterial placement if the flow is pulsatile.

Related posts:

Recognizing the Imaging Findings of Trauma Recognizing Pneumonia Recognizing the Normal Abdomen Computed Tomography Recognizing Some Common Causes of Neck and Back Pain Ultrasonography

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Mar 2, 2016 | Posted by in GENERAL RADIOLOGY | Comments Off on Recognizing the Correct Placement of Lines and Tubes

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