CVC and Deep S…

A systematic approach to the assessment of the chest radiograph is required. A simple structure takes the following approach:

1. Summary
2. Technical aspects
3. Lungs & pleural cavity
4. Heart & mediastinum
5. Bones
6. Soft tissues
7. Indwelling devices

This is an AP film of a supine patient. The most striking finding is the presence of extensive ‘hardware’:

• L) subclavian and R) IJ central lines, tips appropriately placed
• Endotracheal tube
• Thoracic spinal fixation
• Thoracic aortic stent
• Surgical staples
• ECG leads

Additionally:

Technical aspects:

• Film is minimally rotated, adequately exposed
• All aspects of interest are located within the field

Lungs and pleural cavity:

• Prominent horizontal fissure (right)
• Mild alveolar opacification in the left lower lobe, consistent with possible pulmonary contusion, given the mechanism of injury

Heart and mediastinum:

• Cardiothoracic ratio is ~50%, although that can be accounted for by the AP projection
• Right and left mediastinal contours appear normal
• Thoracic aortic stent, extending to the level of the left subclavian artery

Bones:

• Bilateral rib fractures
• Thoracic spinal fusion

Soft tissues:

• Normal diaphragmatic outlines
• Absence of deep sulcus sign

The most striking finding is the presence of a ‘deep sulcus sign’ on the left, with hyperlucency and absence of lung markings, consistent with a left pneumothorax.

Other findings include:

• Left rib fractures
• Possible tracheal deviation to the right (difficult to determine given the presence of metalwork and the patient’s positioning)
• Hardware: ETT, L) internal jugular CVC, thoracic spinal fusion, pelvic external fixation and ECG leads

The deep sulcus sign is an indirect sign of a pneumothorax, found on supine chest radiographs. It is caused by the non-dependent distribution of intrapleural air, producing abnormal anterior diaphragmatic lucency, and thus a deepening of the costophrenic angle, as air tracks latero-caudally.²

Pneumothorax is a common complication of CVC insertion, representing up to 30% of mechanical adverse events. The likelihood of mechanical complications is largely determined by three categories of factors;¹

1. Patient-related factors (underlying disease, co-morbidity, anatomy, compromised procedural settings, patient restlessness or lack of co-operation, previous operations/trauma/radiotherapy).
2. Catheter-related factors (site, catheter type).
3. Clinical factors (Operator experience, previous catheterizations, catheterization attempts, emergency vs. elective situation).

Pneumothorax is the most likely mechanical complication associated with subclavian vein cannulation (see below).¹

Table from Tsotsolis, N. et al (2015)

CVC-associated pneumothorax can be prevented or rapidly managed through the following:

• Recognition of risk factors for difficult catheterization
• Use of a standard method of CVC insertion
• Assistance from an experienced clinician,
• Use of ultrasound guidance
• Early recognition of the presence of pneumothorax
• Use of a standardized treatment algorithm.

The rationale for each of these interventions is outlined in the table below;¹

From Tsotsolis et al (2015)