Measurement of the optic nerve sheath with the usual measurement method and the CLOSED protocol. Concordance study among the doctors of the intensive care unit of the General Teaching Hospital of Ambato

Introduction: measuring the diameter of the optic nerve sheath is a widely used procedure for neuromonitoring, since it is a fairly reliable indicator of the state of intracranial pressure. Objective: To establish the degree of correlation and concordance between the traditional measurements and with the CLOSED protocol of the diameter of the optic nerve, among the doctors of the Intensive Care Unit of the General Teaching Hospital of Ambato Methods: A descriptive, cross-sectional, agreement study was carried out. Fifteen general practitioners residing in the ICU of the General Teaching Hospital of Ambato were included. A healthy volunteer was selected for optic nerve sheath diameter measurement. Measurements were made with the usual technique and, following the CLOSED protocol with ultrasound. Agreement was determined using the Bland-Altman method. Results: Traditional method: right sheath (x̄: 0.442; SD: 0.111); left sheath (x̄: 0.486; SD: 0.0995). CLOSED protocol: right sheath (x̄: 0.411; SD: 0.0128); left sheath (x̄: 0.445; SD: 0.00834). Pearson's correlation coefficient: right sheath: r= 0.190 (p= 0.499); left sheath: r= 0.024 (p= 0.932). Concordance coefficient: right sheath (53.3%; 95% CI: 52.3%-54.3%), left sheath (46.7%; 95% CI: 45.7%-47.7%). Conclusions: There is a weak correlation and moderate agreement between the traditional measurements and with the CLOSED protocol of the diameter of the optic nerve among the doctors of the Intensive Care Unit of the General Teaching Hospital of Ambato. This shows the need to reinforce continuous training activities and the learning curve with these doctors.