- While looking at the patient, an imaginary line should be drawn across the top of the shoulders and another across the bottom of the chin.
- Measure the space/distance between the two imaginary lines using your fingers. Note how many fingers wide this space is.
- Select a collar. The distance between the sizing post (black fastener) and the lower edge of the rigid plastic should match the distance of the finger widths previously measured. If not, select another size of collar until a size matches. Be aware that different manufacturers may use different measuring points. Note that some patients anatomically will not fit into a c-collar. In this situation towels or a blanket roll may be used.
- After selecting the appropriate sized collar, slide the c-collar up the chest wall into place. The chin should rest on the chin piece. The chin must not be able to retract into the chin piece (this may cause airway issues if not fixed).
- Pull the remainder of the collar around the neck and secure the Velcro. Once the Velcro has been fastened, the collar should be snug around the neck. If properly applied, the patient will not be able to move head forward and backward and/or left and right.
- Recheck the position of the head. Head should still be in the neutral position and aligned straight. If not, adjust or select a different size c-collar.
Most cervical collars have an opening at the anterior neck, which allows for only limited examination. Therefore, the neck must be thoroughly assessed prior to the application of the cervical collar.
Cervical collars do not accommodate an angulated or rotated head. Therefore, DO NOT attempt to apply a cervical collar if the head is not in an in-line position.
Cervical collars DO NOT “immobilize” the neck. They allow for 25-30% of motion by flexion and extension and up to 50% for other types of motion.
A unique function of the cervical collar is to rigidly maintain a minimum distance between the head and neck to eliminate intermittent compression of the cervical spine.
An incorrectly sized cervical collar may cause hyper-flexion, hyperextension, or compression of airway and great vessels.
A cervical collar that hinders the mouth from opening may lead to aspiration if the patient vomits.
Improperly sized cervical collars may result in complications if:
- too loose it is ineffective and can cover the anterior chin, mouth, and nose resulting in airway obstruction.
- too tight it can compress the carotid arteries and neck veins.
- too short it will not protect the cervical spine from compression and allows for significant flexion.
- too tall it will cause hyperextension of the head.
There are times when a patient’s neck cannot be properly fitted with a cervical collar at all. In these cases, improvised devices must be used (towel roles, trauma dressings, rolled blankets) in an attempt to restrict the movement of the patient’s head and neck.