The Preventive Effect of Dexmedetomidine Against Delirium in Patients with Aortic Dissection: A Retrospective Cohort Study

Background: Dexmedetomidine (DEX) is often used to reduce the incidence of delirium in intensive care unit (ICU) patients. However, it was found in our clinical practice that the incidence of delirium in some patients with aortic dissection (AD) remained high even after using DEX. The aim of the present study was to clarify whether the protective effects of DEX against delirium were different between Stanford type A and B AD patients during ICU stay. Methods: Data of patients with Stanford type A or B AD who were treated in the ICU of our hospital between 2015 and 2018 retrospectively were reviewed. They were divided into four groups: A1 group (Stanford type A AD patients using DEX), A2 group (Stanford type A AD patients without using DEX), B1 group (Stanford type B AD patients using DEX), and B2 group (Stanford type B AD patients without using DEX). Patients in A1 and B1 groups received intravenous administration of DEX within 1 h admission to the ICU and after surgery or stent implantation at a loading dose of 1 µg/kg, followed by continuous infusion of 0.2–0.7 µg/(kg·h) for >24 h. The mortality rate, delirium incidence, length of ICU stay, and drug administration were compared between the four groups. Results: After intravenous administration of DEX, the delirium incidence in B1 group was reduced significantly compared with that in B2 group (2.8% vs. 17.8%, P = 0.04), while there was no significant difference between A1 and A2 group (20.8% vs. 24.3%, P = 0.7). However, DEX administration significantly reduced the use of anti-hypertensive drugs (P = 0.04) and morphine (P = 0.02) in Stanford type A AD patients. Conclusion: The use of DEX reduced the incidence of delirium in Stanford type B AD patients during ICU stay, therefore reducing the risk of medical accidents and risk of rupture of the aortic dissecting aneurysm. The preventive effect of DEX against delirium in Stanford type A AD patients was not obvious, and whether increasing the dosage of DEX could enhance the therapeutic efficacy in this group of patients needs to be further observed in future studies.