Objective: To investigate the effect of the fluid challenge test on the optic nerve sheath diameter (ONSD) change.
Study design: Quasi-experimental study.
Place and duration of study: Department of Anesthesiology and Reanimation, Ondokuz Mayis University Hospital, Samsun, Turkey, from January to November 2021.
Methodology: A fluid challenge was defined as a 500 mL crystalloid infusion administered over 10 minutes, and fluid responsiveness was defined as a subsequent increase in stroke volume of at least 15% administered to the ICU patients. The ONSD and hemodynamic variables were measured by ultrasonography before (T0), at the end (T1), and 30 min after the fluid challenge (T2). The primary outcome of the study was the change in ONSD measurements associated with the fluid challenge, and the secondary outcome was the relationship between fluid responsiveness and the change in ONSD.
Results: A total of 60 patients were included. The ONSD (mm) value was significantly higher at T1 compared to T0 (mean ± standard deviation: 5.12±0.30 mm vs. 5.10±0.32 mm; p=0.011). However, at T2, the ONSD was similar to that at T0 (5.10±0.31 mm vs. 5.10±0.32 mm; p=0.662). The stroke volume (mL) was also significantly higher at T1 and T2 compared to T0 [median IQR 60 (6) mL vs. 60 (4.7) mL vs. 52 (5) mL, respectively, p <0.01]. No significant relationship was found between the ONSD and the change in fluid responsiveness (p=0.621).
Conclusion: The fluid challenge test increases ONSD and may cause an increase in intracranial pressure.
Key words: Fluid therapy, Stroke volume, Intracranial pressure, Ultrasonography, Optic nerve sheath diameter.