Value of optic nerve sheath area determined by ultrasound in assessing intracranial pressure of craniocerebral trauma patients

Objective To investigate the validity and feasibility of optic nerve sheath area (ONSA) determined by ultrasound in evaluating intracranial pressure (ICP) of craniocerebral trauma patients. Methods This was a prospective clinical trial. Thirty-six patients with craniocerebral trauma who were hospitalized in intensive care unit (ICU) of Changshu No.1 People’s Hospital from June 2015 to June 2018 were selected as research objects. On 1, 3 and 5 days postoperatively, bedside ultrasound was used to measure diameter of the optic nerve sheath 3 mm behind the eyeball. The optic nerve sheath long diameter (ONSLD) and optic nerve sheath vertical diameter (ONSVD) were measured in the horizontal axis and the sagittal position, respectively. The ONSA was calculated according to ONSLD and ONSVD. At the same time, ICP values were monitored. Results ONSLD, ONSVD and ONSA determined by ultrasound were significantly correlated with ICP (r=0.493, 0.507, 0.551; P=0.000, 0.000, 0.000). The correlation between ONSA and ICP was higher than ONSLD and ONSVD. Optimal cut-off values of ONSLD, ONSVD and ONSA for detection of elevated ICP(>20 mmHg, 1 mmHg=0.133 kPa)were 5.6 mm, 5.75 mm, 26.52 mm2, with sensitivity of 73.7%, 73.7%, 73.7%, specificity of 86.5%, 91.1%, 92.1%. Conclusions ONSLD, ONSVD and ONSA have good correlations with ICP and higher predictive value for increased intracranial. But ONSA has a closer correlation with ICP and has clinical application value. Key words: Ultrasound; Optic nerve sheath; Area; Intracranial pressure