Cervical Collar-Induced Increased Intracranial Pressure
The nurse should observe for compression of jugular veins due to cervical collar tightness, which is a well-documented cause of increased ICP in head-injured patients.
Mechanism of ICP Elevation from Cervical Collars
The application of cervical collars causes a measurable and clinically significant increase in intracranial pressure through external compression of the jugular veins, creating a "venous tourniquet" effect that impedes venous drainage from the brain 1. This mechanism has been demonstrated across multiple studies:
Cervical collars increase ICP by approximately 4.4 mmHg on average (95% CI: 1.70-7.43 mmHg), with this elevation being statistically significant across pooled data from 86 patients 1, 2
ICP decreases by approximately 3 mmHg after collar removal, confirming the direct causal relationship between collar application and elevated ICP 2
Interface pressures beneath cervical collars frequently exceed 10 mmHg, with individual readings reaching 30 mmHg—sufficient to cause jugular venous obstruction 3
Increased jugular vein cross-sectional area has been documented with collar application (MD: 0.19; 95% CI: 0.05-0.33), indicating venous compression and impaired drainage 1
Clinical Significance in Head-Injured Patients
This ICP elevation is particularly dangerous in head-injured patients like this skier, where intracranial compliance is already reduced 4. The 2015 International Consensus on First Aid Science specifically identified increased intracranial pressure as a critical complication of cervical collar use, noting this as a key reason to suggest against routine collar application by first aid providers 1.
In patients with co-existing head injury (present in up to one-third of cervical spine trauma cases), the collar-induced ICP elevation can worsen outcomes and contribute to secondary neurological injury 1, 4.
Why Other Options Are Incorrect
Hyperemia due to jugular vein dilation: This is backwards—the problem is venous compression (not dilation), which causes venous congestion and secondary ICP elevation 3
Compression of parenchyma due to decreased BP: Decreased blood pressure would reduce cerebral perfusion pressure but not directly cause ICP elevation through the collar mechanism 5
Pressure on back of head due to lack of movement: While prolonged immobilization causes multiple complications (pressure sores, pneumonia, thromboembolic events), direct pressure on the occiput is not the primary mechanism of ICP elevation from cervical collars 1
Nursing Monitoring Priorities
The nurse should specifically assess for:
Signs of elevated ICP: Deteriorating level of consciousness, pupillary changes, worsening headache, vomiting, or new neurological deficits 5
Collar fit and tightness: Ensuring the collar is not excessively tight, particularly around the anterior neck where jugular compression occurs 3
Timing of complications: ICP-related complications from collars can develop rapidly, unlike pressure sores which typically appear after 48-72 hours of immobilization 1
Critical Caveat
The evidence suggests cervical collars may not effectively stabilize unstable cervical injuries and can cause paradoxical movement at the craniocervical and cervicothoracic junctions—the two most common injury sites 1. However, in this acute trauma setting with suspected cervical spine injury, the collar remains in place pending definitive clearance, making vigilant monitoring for ICP complications essential 1.