Impact of hypotension and global hypoperfusion in postoperative delirium: a pilot study in older adults undergoing open colon surgery

BACKGROUND: Post-operative delirium is a serious complication in patients undergoing major abdominal surgery. It remains unclear whether peri-operative hemodynamic and perfusion variables affect the risk for postoperative delirium. The objective of this pilot study was to evaluate the association between perfusion and hemodynamics peri-operative with the appearance of post-operative delirium. METHODS: Prospective cohort study of adults 60 years or older undergoing elective open colon surgery. Multimodal hemodynamic and perfusion variables were monitored, including central venous oxygenation (ScvO(2)), lactate levels, and non-invasive cerebral oxygenation (rSO(2)), according to a standard anesthesia protocol. Fisher's exact test or Student's t-test were used to compare patients who developed post-operative delirium with those who did not (p < 0.05). RESULTS: We studied 28 patients, age 73 ± 7 years, 60.7% female. Two patients developed post-operative delirium (7.1%). These two patients had fewer years of education than those without delirium (p = 0.031). None of the peri-operative blood pressure variables were associated with incidence of post-operative delirium. In terms of perfusion parameters, postoperative ScvO(2) was lower in the delirium than the non-delirium group, without reaching statistical significance (65 ± 10% vs. 74 ± 5%; p = 0.08), but the delta-ScvO(2) (the difference between means post-operative and intra-operative) was associated with post-operative delirium (p = 0.043). Post-operative lactate and rSO(2) variables were not associated with delirium. CONCLUSIONS: Our pilot study suggests an association between delta ScvO(2) and post-operative delirium, and a tendency to lower post-operative ScvO(2) in patients who developed delirium. Further studies are necessary to elucidate this association.