• 
• 

Three Part Question

In [patients with traumatic brain injury (TBI)] Is [the application of a cervical collar compared to no collar significant] At [maintaining intra cranial pressure (ICP)]

Clinical Scenario

You are on scene with a patient who has been assaulted via a blow to the head with an unknown object. The patient has a GCS 8 giving a preliminary diagnosis of serious traumatic brain injury. You also remain suspicious that they may also have a fracture cervical spine which is the case in 5% of patients with TBI. You wonder if the application of cervical collar will increase intracranial pressure (ICP)

Search Strategy

PubMed and Google Scholar (from2020) using search terms:
"Cervical collar" AND "ICP" - "Cervical collar" AND "Intracranial pressure" AND "traumatic brain injury"

Search Outcome

337 papers found, after critical appraisal 4 papers were relevant to the 3 part question and were subsequently used.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Rafael A Núñez-Patiño, Andres M Rubiano, Daniel Agustin Godoy 2020 Argentina	5 studies including 86 patients who were suffering from moderate to severe TBI	Systematic review and meta-analysis - CEBM 1a	The paper explores the impact of cervical collars on intracranial pressure in patient with traumatic brain injury	The paper rejects the null hypothesis and shows an overall increase in ICP after a cervical collar was applied p=<0.01 with a mean increase in 4.4mmHg. After removal of the collar, the ICP reduced by a mean of 3mmHg p=<0.02.	Small sample size. The angle of the patients was not considered a variable in the studies. The studies did not state how the ICP measurement was obtained. The correct fitting of the collar to the patient was not mention.
K. Hunt, S. Hallworth, M. Smith 2001	30 patients with severe traumatic brain injury in a neurosurgical intensive care unit	Random control trial - SEBM 1b	The paper explores the impact of cervical collars on intracranial pressure in patient with traumatic brain injury	Results showed a significant rise from baseline ICP with a mean 4.6mmHg p=<0.0001 in patients with cervical collar applied. The mean rise was greater in patients with a base line of >15mmHg p=<0.05. There was no change in cardiorespiratory parameters.	The study did not state how ICP was obtained, relatively small cohort of 30 patients. In hospital application of collar may be applied for shorter period of time compared to pre-hospital application.
Ralph J Mobbs, Marcus A Stoodley, John Fuller 2002	10 patients with head injury with a GCS<9 with ICP measurements taken before and after the application of cervical collar	Prospective Series - CEBM 2b	The paper explores the impact of cervical collars on intracranial pressure in patient with traumatic brain injury.	There was an observed mean rise in ICP of 4.4mmHg p=<0.05 after cervical collar was applied. Patients in group C had highest change in ICP but also had better outcomes. Pateint's with initially higher ICP had overall worse outcomes.	Small cohort of 10 participants, standardisation of fitting of the collar not documented. The angle of the patient not documented. In hospital application of collar may be applied for shorter period of time compared to pre-hospital application.
Bazaie , Naif. Alghamdi, Ibrahim. Alqurashi, Naif. Ahmed, Zubair 2021 UK	88 patients with traumatic brain injury arriving at hospital wearing cervical collar. 6 studies were included	Systematic Review and Meta-Analysis CEBM 1a	The paper explores the impact of cervical collars on intracranial pressure in patient with traumatic brain injury arriving at hospital wearing a cervical collar.	In all studies bar one there was a significant rise in ICP with a mean of 3.57mmHg p=<0.002 which returned to near normal after removal of cervical collar.	Small cohort, collars in place for small amount of time compared with pre-hospital where they could be in place for much longer. One paper in the study was not available for analysis.

Comment(s)

The studies that have explored the relationship between the application of cervical collar and intercranial pressure (IPC), all reject the null hypothesis that there is no change in measured ICP in adult patient with traumatic brain injury, who are wearing a cervical collar. All studies have concluded that, in adult patients with TBI, when a cervical collar is applied, there is an associated rise in ICP. The increase ranges from 3.57mmHg-4.6mmHg (mean 4.20mmHg). A study completed by (Mobbs et al., 2002) concluded that, a patient group with the highest observed ICP, post collar application, also had the best clinical outcome. It was also observed that the patient group with the highest initial ICP had the worst clinical outcome. This may demonstrate that the relationship between the increase in ICP from cervical collar, is not associated with adverse clinical outcomes. Instead, the primary injury and post injury bassline ICP, may be more relevant to the patient’s prognosis.

Clinical Bottom Line

Due to the observed risk of increasing ICP, the application of a cervical collar should be a caution in patients with a diagnosis or suspected diagnosis of TBI. If already high, the application of a collar could increase the ICP higher, putting patients at an increased risk of secondary brain injury, which is what we try to prevent in the management of TBI. If cervical collar has been applied, it would be beneficial to obtain imaging to clear the spine, enabling prompt removal to the cervical collar. Or were possible, utilise other mean of cervical stabilisation, such as head blocks or blanket rolls. More research needs to be conducted exploring the relationship between initial bassline ICP and patient outcomes.

References

1. Rafael A Núñez-Patiño, et al Impact of Cervical Collars on Intracranial Pressure Values in Traumatic Brain Injury: A systematic Review and Meta-Analysis of Prospective Studies PubMed 2020 - 469-477
2. K. Hunt, et al The effects of rigid collar placement on intracranial and cerebral perfusion pressures Anaesthesia 2001 - 511-513
3. Ralph J Mobbs, et al Effect of cervical hard collar on intracranial pressure after head injury PubMed 2002 - 1445-2197
4. Bazaie. N, et al The impact of a cervical collar on intracranial pressure in traumatic brain injury patients Trauma Care 2021 - 1-10