The Influence of Cervical Collar Immobilization on Optic Nerve Sheath Diameter

Effect of a cervical collar on optic nerve sheath diameter in trauma patients

BACKGROUND

As advocated in advanced trauma life support and prehospital trauma life support protocols, cervical immobilization is applied until cervical spine injury is excluded. This study aimed to show the difference in optic nerve sheath diameter (ONSD) between patients with and without a cervical collar using computed tomography (CT).

METHODS

This was a single-center, retrospective study examining trauma patients who presented to the emergency department between January 1, 2021, and December 31, 2021. The ONSD on brain CT of the trauma patients was measured and analyzed to determine whether there was a difference between the ONSD with and without the cervical collar.

RESULTS

The study population consisted of 169 patients. On CT imaging of patients with (n=66) and without (n=103) cervical collars, the mean ONSD in the axial plane were 5.43 ± 0.50 mm and 5.04 ± 0.46 mm respectively for the right eye and 5.50 ± 0.52 mm and 5.11 ± 0.46 mm respectively for the left eye. The results revealed an association between the presence of a cervical collar and the mean ONSD, which was statistically significant (P<0.001) for both the right and left eyes.

CONCLUSION

A cervical collar may be associated with increased ONSD. The effect of this increase in the ONSD on clinical outcomes needs to be investigated, and the actual need for cervical collar in the emergency department should be evaluated on a case-by-case basis.

Current status of point of care ultrasonography for the perioperative care of trauma patients

PURPOSE OF REVIEW

The incorporation of point of care ultrasound into the field of anesthesiology and perioperative medicine is growing at rapid pace. The benefits of this modality align with the acuity of patient care and decision-making in anesthetic care of a trauma patient.

RECENT FINDINGS

Cardiac ultrasound can be used to diagnose cardiac tamponade or investigate the inferior vena cava to assess volume status in patients who may suffer from hemorrhagic shock. Thoracic ultrasound may be used to rapidly identify pneumothorax or hemothorax in a patient suffering chest wall trauma. In addition, investigators are exploring the utility of ultrasonography in traumatic airway management and elevated intracranial pressure. In addition, the utility of gastric ultrasound on trauma patients is briefly discussed.

SUMMARY

Incorporation of point of care ultrasound techniques into the practice of trauma anesthesiology is important for noninvasive, mobile and expeditious assessment of trauma patients. In addition, further large-scale studies are needed to investigate how point of care ultrasound impacts outcomes in trauma patients.

Diagnostic utility of point of care ultrasound in identifying cervical spine injury in emergency settings

Introduction

The evaluation of cervical-spine in a major trauma patient needs a bedside efficient tool to rule out cervical spine injury as the role of X-ray and Computed Tomography (CT) in this setting is limited. Point of care ultrasonography (POCUS) is being used as an adjunct during trauma resuscitation. The aim of this study was to evaluate the use of POCUS for identifying cervical spine injuries.

Methods

We recruited 84 cases with cervical spine injury based on CT scan after taking consent. POCUS was used as per the operational definition of study methods while maintaining manual in-line stabilisation. Statistical analysis was done by using STATA version 14.

Results

Normal cervical anatomy was visible through anterior approach in POCUS except for the 1^st and 2^nd cervical vertebrae. The sensitivity and specificity of POCUS vs CT scan for vertebral body listhesis were 84.52% (95% CI of 0.65-0.95) and 89.66% (95% CI 0.78-0.96) with p-value <0.0001. Sensitivity and specificity of POCUS vs CT for vertebral body fracture were 40.91% (95% CI of 0.20-0.63) and 96.77% (95% CI of 0.88-0.99) with p-value <0.0001. The overall sensitivity and specificity of POCUS were 45.83% and 83.33% (p = 0.06) and excluding isolated posterior column injuries, sensitivity and specificity were 70.21% and 83.33% (p < 0.05).

Conclusion

POCUS identified injuries such as fracture and listhesis. Because of high rate of missed injuries, ultrasound at present cannot be used as a screening or diagnostic tool for decision-making in cervical spine injury.

Effect of 5 different cervical collars on optic nerve sheath diameter: A randomized crossover trial

BACKGROUND

There is considerable evidence that prolonged use of cervical collars potentially cause detrimental effects including increase in optic nerve sheath diameter (ONSD) among healthy volunteers. Different types of cervical collars immobilize cervical spine variably well and may presumably differently influence the venous compression and hence the intracranial pressure. We therefore aimed to evaluate the influence of cervical spine immobilization with 5 different types of cervical collars on ONSD measured noninvasively by ultrasound on healthy volunteers.

METHODS

We conducted a randomized crossover trial including 60 adult healthy volunteers. Control assessment of the optic nerve sheath thickness was performed in both sagittal and transverse planes. Patient was placed supine on a transport stretcher, cervical collar was placed, and ONSD measurement was performed after 5 and 20 minutes. During the next days, the procedure was repeated with random allocation of participants and random cervical collar.

RESULTS

Sixty healthy volunteers were included in our study. ONSD left diameter [mm] for the baseline was 3.8 [interquartile range (IQR): 3.65-3.93)] mm. Using AMBU after 5 min, ONSD was changed up to 4.505 (IQR 4.285-4.61; P < .001) mm. The largest change at 5 minutes and 20 minutes was using Philly 4.73 (IQR: 4.49-4.895; P < .001) and 4.925 (IQR: 4.65-5.06; P < .001), respectively. Necklite reported the lower change in ONSD: 3.92 (IQR: 3.795-4; P = 1.0) mm in 5 minutes and 3.995 (IQR: 3.875 - 4.1; P = 1.0) mm in 20 minutes. ONSD right diameter [mm] for the baseline was 3.8 (IQR 3.675-3.9) mm. Using AMBU after 5 minutes, ONSD was changed up to 4.5 (IQR 4.21-4.6) mm. The largest change at 5 minutes and 20 minutes was using Philly 4.705 (IQR 4.455-4.9) and 4.93 (IQR 4.645-5.075), respectively. Necklite reported the lower change in ONSD -33.9 (IQR 3.795-3.99) mm in 5 minutes and 3.995 (IQR 3.86-4.09) mm in 20 minutes.

CONCLUSION

We report significant increase of ONSD from the baseline after cervical collar placement among healthy volunteers at 5 minutes and 20 minutes interval. In addition, no significant difference was noted between ONSD measurements at 5 and 20 minutes. Clinicians should take proactive steps to assess the actual need of cervical collar case by case basis. Nonetheless, when needed, Necklite moldable neck brace seems to be a reasonable option.Registration: ClinicalTrials database (www.clinicaltrials.gov, NCT03609879).