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

Abstract

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 (ScvO₂), lactate levels, and non-invasive cerebral oxygenation (rSO₂), 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 ScvO₂ 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-ScvO₂ (the difference between means post-operative and intra-operative) was associated with post-operative delirium (p = 0.043). Post-operative lactate and rSO₂ variables were not associated with delirium.

Conclusions: Our pilot study suggests an association between delta ScvO₂ and post-operative delirium, and a tendency to lower post-operative ScvO₂ in patients who developed delirium. Further studies are necessary to elucidate this association.

Keywords: Central venous oxygen saturation; Cerebral oxygenation; Delirium; Delírio; Global perfusion; Hipotensão; Hypotension; Lactate; Lactato; Oxigenação cerebral; Perfusão global; Saturação venosa central de oxigênio.