Clinical utility of an automated pupillometer for assessing and monitoring recipients of liver transplantation

Abstract

Pupil examination has been used as a basic measure in critically ill patients and has great importance for the prognosis and management of disease. An automated pupillometer is a computer-based infrared digital video system by which the accuracy and precision of the pupil examination are markedly improved. We conducted an observational study of pupil assessment with automated pupillometry in clinical liver transplantation settings, including pretransplant evaluations and posttransplant surveillance. Our results showed that unconscious patients (grade 4 hepatic encephalopathy) had a prolonged latency phase (left side: 283 +/- 80 milliseconds; right side: 295 +/- 96 milliseconds) and a reduced pupillary constrictive ratio (left direct response: 0.23 +/- 0.10; left indirect response: 0.21 +/- 0.07; right direct response: 0.20 +/- 0.08; right indirect response: 0.21 +/- 0.08) in comparison with normal and conscious patients. After liver transplantation, the recovery of pupillography in these patients was slower than that in conscious patients. However, the surviving recipients without major complications all had a gradual recovery of pupillary responses, which occurred on the first or second posttransplant day. We also reported 4 cases of futile LT in the absence of pretransplant pupillary responses and other pupillary abnormalities revealed by automated pupillometry in our study. In conclusion, patients with grade 4 hepatic encephalopathy had a sluggish pupil response and a delayed recovery pattern after LT. An automated pupillometer is potentially a supplementary device for pretransplant screening and posttransplant monitoring in patients undergoing LT, but further prospective studies are required.