Thoracic imaging in the ICU

Chest X ray

Muhammad AbdelmoneimFellow-Critical Care

Objectives• The debate of routine X ray in ICU• Recommendations for X ray in ICU • Rapid review of hardware assessment in CXR• How to identify Pulmonary edema in CXR• Vascular pedicle width (VPW)

References

Indian Journal of Radiology and Imaging, Vol. 21, No. 3, July-September, 2011, pp. 182-190 Chest Radiology, A pictorial essay: Radiology of lines and tubes in the intensive care unit Sanjay N Jain

When to do X ray chest for ICU patients?

Routine Vs On demand X ray chest?

Recommendation

Routine daily chest radiographs are not indicated for patients admitted to the ICU. In stable patients admitted for cardiac monitoring, or in stable patients admitted for extrathoracic disease only, an initial ICU admission radiograph is recommended; follow-up radiographs should be obtained only for specific clinical indications including clinical worsening and tube or line insertion.

ETT• Every tracheal intubation should be followed by CXR

• Carina T5 (±) vertebra in 95 %

• ETT should be 5-7 Cm above the carina

• Flexion and extension can displace it up to 2 Cm

• When the carina is not visible, the tip of the ET tube should be approximately at the level of the medial ends of the clavicle

The cuff should occupy all the lumen without distending the

wall

Left Lung or Right upper lobe atelectasis ,suction leads to mucosal injury at the carina , hyperinflation of the ipsilateral lung, or pneumothorax

Complications of deep ETT

Accidental Ex-tubation, aspiration and vocal cord injury

Complications of high ETT

physical examination predicted malpositioned tubes in 3% of patients, whereas the radiographs showed malpositioning in 14% of patients in one study and 28% in the other.

Recommendation

Very few malpositioned tubes are detected by physical examination. Radiographs immediately postintubation are indicated to ensure proper positioning.

Tracheostomy Tube

• Should run down parallel to the tracheal air column

• At least 2/3 of the strait portion inside the trachea

• The tip should be several meters above the carina, ( half way between the stoma and the carina),or D3

• Unlike the ET tube, its position is maintained with neck flexion and extension

Why do we perform X ray chest

post tracheostomy?

• Pneumothorax

• Pneumomediastinum

• Tube position

• Widened mediastinum ( hemorrhage)

• Mild cutaneous emphysema in the neck, and pneumomediastinum is insignificant

Central Venous Catheters

• Upper limito The tip of the line should be distal to the last venous valve

• Lower limito Not to enter the right atrium, otherwise dysrhythmia or injection of

undiluted toxic medications into the heart

Central Venous Catheters

Central Venous Catheters

Central Venous Catheters

• The optimal catheter tip position is controversial, and controlled studies are lacking.

• The distal tip of jugular catheters should lie in the lower superior vena cava

• To minimize the likelihood of cardiac complications, some guidelines recommend catheter tip position outside the right atrium and above the pericardial reflection.

• The right superior heart border on chest radiography is not a reliable determinant of right atrial position

• The carina and right tracheobronchial angle represent reliable landmarks for the pericardial reflection and right-sided catheters should generally be positioned above this point 

http://www.uptodate.com/contents/placement-of-jugular-venous-catheters

Feeding Tubes• A chest radiograph is warranted after initial nasogastric

tube insertion and before the first feeding

• A mal positioned feeding tube often produces no clinical signs but can be disastrous

• the tip should be 10 Cm distal to Gastroesophageal Junction

• The tip of a naso-gastric tube should also lie on the left. If it crosses the midline it has entered the duodenum

• Tube descends in the midline

• Tube bisects the carina

• Tube crosses the diaphragm in the midline

• The tip sits below the diaphragm

X ray After feeding tube insertion: What are the signs indicating right location?

NGT Mal Positions

pulmonary edema• Increased hydrostatic pressure oedema, two

pathophysiological and radiological phases are recognized in the development of pressure oedema o interstitial oedema o alveolar flooding or oedema

these phases are virtually identical for left-sided heart failure and fluid overload • Permeability oedema with diffuse alveolar damage (DAD)• Permeability oedema without diffuse alveolar damage • Mixed edema due to simultaneous increased hydrostatic

pressure and permeability changes

Cephalization

Interstitial edema

Peribronchial cuffing Kerley lines

• Specific to hydrostatic edema• If present in permeability edema

(1/3 of cases) means combined

• Septal lines almost never in permeability edema

Alveolar edema

• The vascular pedicle width (VPW) is the distance between parallel lines drawn from the point at which the superior vena cava intersects the right main bronchus an a line drawn at the take off of the left subclavian artery from the aorta. The mean vascular pedicle width is 38-58 mm on posteroanterior