Inter-rater Reliability of Ultrasonographic Measurements of Optic Nerve Sheath Diameter Performed by Emergency Nurses.

Introduction: We aimed to determine the inter-rater reliability of ultrasonographic optic nerve sheath diameter measurements performed by emergency nurses.

Methods: Point-of-care ultrasound of the optic nerve sheath diameter measurements were performed in B-mode using a 10 MHz linear probe. The emergency nurses had no previous experience in ultrasonography. Emergency nurses performed sonographic measurements on patients in groups of 2. First, 1 emergency nurse measured optic nerve sheath diameter in both the right and left eyes of the patient, and then the other emergency nurse measured optic nerve sheath diameter in the right and left eyes of the same patient. Thus, a total of 4 optic nerve sheath diameter measurements were made by 2 emergency nurses in both eyes of 1 patient. Four emergency nurses measured optic nerve sheath diameter in 25 separate patients. As a result, a total of 600 optic nerve sheath diameter values were obtained in 150 patients. Each emergency nurse recorded their results on data collection forms and was blinded to each other's measurements.

Results: The median optic nerve sheath diameter was 3.6 mm (interquartile range, 0.6). The median optic nerve sheath diameters of males and females were 3.7 mm (interquartile range, 0.6) and 3.5 mm (interquartile range, 0.6), respectively. The intraclass correlation coefficient was 0.89 (95% CI, 0.86-0.91). The intraclass correlation coefficient values for the optic nerve sheath diameter measurements of the right and left eyes were 0.89 (95% CI, 0.85-0.92) and 0.88 (95% CI, 0.83-0.91), respectively.

Discussion: There is good inter-rater reliability among emergency nurses with no previous experience in measuring the optic nerve sheath diameter with point-of-care ultrasound.