Acute changes in plasma sodium concentration are not related to intracranial pressure in patients with fulminant hepatic failure

We proposed a relationship between plasma sodium concentration ([Na]) and intracranial pressure (ICP) in patients with fulminant hepatic failure (FHF). We identified from our database patients admitted to our hospital with FHF between 2000 and 2005 in whom ICP monitoring was performed. We obtained [Na] at admission to the referring hospital, and on admission to our hospital, from the database. We then performed a retrospective case- note review, and recorded ICP, cerebral perfusion pressure, body temperature, partial pressure of CO2, partial pressure of O2, arterial hydrogen ion concentration, and the temporally closest [Na] at two time points – the time at which the ICP monitor was inserted, and the time at which the highest ICP was recorded. We found no linear relationship between [Na] and ICP at either point.
We proposed that acute change in [Na] might be more relevant, and calculated the change in [Na] from admission to hospital to the times of ICP monitor insertion (DifBolt) and highest ICP (DifHigh). Mean DifBolt was -3±5.9 mmol l-1, and mean DifHigh was
-3±6.2mmol l-1. Again, we could determine no linear relationship between acute change in [Na] and ICP.
We conclude that we have found no evidence for a link between acute change in plasma
sodium and ICP in a subset of patients admitted to our facility with FHF. A prospective
study is planned.