Author’s Response to Letter to the Editor: Noninvasive Intracranial Pressure Assessment in Acute Liver Failure
We would like to thank Dr. De Bernardo and colleagues for their insights into the use of optic nerve sheath diameter (ONSD) measurement for the detection of elevated intracranial pressure (ICP). As demonstrated in our manuscript, there is reason to be concerned about the clinical value of this technique to detect elevated ICP, especially in the setting of critically ill patients with acute liver failure (ALF). We believe that there are several potential explanations for this inaccuracy, as noted in the discussion. The use of amplitude scanning (A-scan) to assess ONSD is certainly an interesting proposal. However, it would be difficult to obtain all of the proposed measurements in ALF patients who are typically unable to cooperate with a clinical exam. In order to determine if the data obtained using an A-scan probe are superior to that obtained using a B-scan probe (which produces a cross-sectional view of the eye and orbit), both measurements would need to be conducted simultaneously and compared to the gold standard of concomitant invasive ICP monitoring. We believe such validation is essential, before ocular sonography of any kind is routinely utilized to assess ICP in ALF.
Venkatakrishna Rajajee, MD; Craig A. Williamson, MD; Robert J. Fontana, MD; Anthony J. Courey, MD; Parag G. Patil, MD, PhD
Source of support
There was no funding associated with this study.
Conflicts of Interest
None of the authors have any conflicts of interest to disclose.