[The correlation between optic nerve sheath diameter and volume status in patients after cardiac surgery]

Objective: To investigate the relationship between optic nerve sheath diameter (ONSD) and volume status of patients after cardiac surgery. Methods: A total of consecutive 56 patients who were treated in Critical Care Unit in Peking Union Medical College Hospital after open heart surgery from January to August 2015 were screened in this study. Central venous pressure (CVP) and 72 h net fluid balance were monitored. ONSD and diameter of inferior vena cava (IVC) were measured by ultrasound. Results: A total of 44 patients were finally included in the study. The postoperative baseline ONSD was (5.31±1.96)mm, compared to (5.07±1.77)mm after 72 h treatment, with ΔONSD(0.22±0.21)mm. Baseline and post-treatment at 72 h CVP were (11.98±4.09)mmHg and (8.95±4.02)mmHg respectively. IVC dropped from (19.75±4.12)mm to (17.11±4.68)mm. ΔONSD and ΔCVP were significantly correlated (r=0.422, P<0.05), ΔONSD and net fluid balance (NFB) at 72 h were significantly correlated (r=-0.388, P<0.05). While ΔONSD were significantly correlated with ΔIVC (r=0.423, P<0.05), ΔCVP and ΔIVC were also significantly correlated (r=0.391, P<0.05). Conclusion: The change of ONSD in patients after cardiac surgery is related to the change of volume status. Therefore ONSD is helpful to estimate brain edema, not only could be a potential index to evaluate volume status, but also be used to guide improving prognosis after cardiac surgery.