[Delirium after vascular surgery interventions. Intermediate-term results of a prospective study]

Postoperative delirium is a common psychic disturbance occurring acutely after various surgical procedures and typically presenting with a fluctuating course. These patients' recovery takes longer. In this study we analyze the incidence of postoperative delirium in patients undergoing vascular surgery and try to identify risk factors for its development.

Patients undergoing elective arterial operations were included. Their medical history, the specific vascular diagnosis and operation performed, the medication and laboratory data were monitored. Additionally the patients were preoperatively interviewed by a psychiatrist. Intraoperatively the drugs, infusions, possible transfusions, blood gases and pressures were monitored, as were the times of surgery and anesthesia. Postoperatively patients were seen daily by the psychiatrist and the surgeon for at least 7 days. Postoperative delirium was diagnosed according to DSM IV criteria, and mild, moderate and severe delirium were distinguished.

Fifty-four patients entered the study. Twenty-one (38.9%) developed postoperative delirium (11 mild, 2 moderate, 8 severe). Patients with aortic operations developed delirium more frequently than those with non-aortic procedures(55.5 vs 22.2%, n = 27 each). Some preexisting diseases (hearing disturbance) increased the probability of postoperative delirium, while age was not identified as a risk factor. General psychopathological and depressive disturbances increased the likelihood of postoperative delirium. Patients who had a severe intraoperative course developed postoperative delirium more frequently. This was not seen in the absolute time of surgery or anesthesia nor in the intraoperative development of blood pressure or intraarterial gases, which did not differ between patients with and without postoperative delirium. More reliable parameters were an increased intraoperative need for crystalloid volume, intra- or postoperatively decreased hemoglobin values (Hb < 10 g/dl) and the development of acidosis that had to be treated. Patients with delirium had serious complications more often (8/21 = 38.1% vs 6/33 = 18.2%) and needed Intensive Care treatment longer (2.7 vs 2.1 days, only aortic surgery 3.2 vs 2.4 days).

Postoperative delirium after vascular surgery is frequent. Patients undergoing aortic surgery, with specific concomitant medical disease, psychopathological disturbances and a severe intraoperative course, are at risk of developing postoperative delirium.