[Causes of postoperative delirium after abdominal surgery in elderly patients]

There are many causes for postoperative delirium in elderly patients. Hypotension is considered as one of the causes. In our retrospective study, hypotension during operation was not taken care of strictly. Slight hypotension was observed every so often. We recognized that the drop of cerebral blood flow due to hypotension and duration of hypotension were risk factors of postoperative delirium.

We did a retrospective study, covering the period between April 1, 2005 and March 31, 2006, in 30 elderly patients for elective laparotomy. We compared postoperative delirium group (D group) with no delirium group (ND group).

There were great differences in transfusion, fluid infusion, anesthesia time, operation time, blood loss, extreme hypotension and the duration of hypotension between the two groups.

Our results indicate that permissive hypotension induced the drop of cerebral blood flow and it can be a risk factor of postoperative delirium in elderly patients. To prevent extreme hypotension, to decrease duration of hypotension, and to raise the blood pressure quickly are very important to decrease postoperative delirium in elderly patients.