Research Article: Dexmedetomidine for the prevention of postoperative delirium in elderly patients undergoing noncardiac surgery: A meta-analysis of randomized controlled trials

Date Published: August 16, 2019

Publisher: Public Library of Science

Author(s): Hai Zeng, Zunjiang Li, Jianbin He, Wenbin Fu, Wisit Cheungpasitporn.


Postoperative delirium (POD) among the elderly population that undergoes noncardiac surgery is significantly associated with adverse clinical outcomes. We conducted this meta-analysis to evaluate the effectiveness and safety of dexmedetomidine for the prophylaxis of POD among the elderly population after noncardiac surgery.

We searched Embase, PubMed, and the Cochrane Library from inception date to March 2019 for randomized controlled trials (RCTs) that compared dexmedetomidine and placebo for the prevention of POD and evaluated the major cardiovascular outcomes among elderly people after noncardiac surgery. Two authors independently screened the studies and extracted data from the published articles. The main outcome was the incidence of POD. The secondary outcomes included the occurrence of bradycardia, hypotension, hypertension, tachycardia, myocardial infarction, stroke, hypoxaemia, and all-cause mortality.

A total of 6 RCTs with 2102 participants were included. Compared with placebo, dexmedetomidine significantly reduced the prevalence of POD (RR = 0.61, 95% CI 0.34–0.76, P = 0.001, I2 = 66%), and the risk of tachycardia (RR = 0.48, 95% CI 0.30–0.76, P = 0.002, I2 = 0%), hypertension (RR = 0.59, 95% CI 0.44–0.79, P < 0.001, I2 = 20%), stroke (RR = 0.22, 95% CI 0.06–0.76, P = 0.02, I2 = 0%), and hypoxaemia (RR = 0.50, 95% CI 0.32–0.78, P = 0.002, I2 = 0%) in elderly patients who underwent noncardiac surgery. However, dexmedetomidine accelerated the occurrence of bradycardia (RR = 1.36, 95% CI 1.11–1.67, P = 0.003, I2 = 0%). Furthermore, no significant differences were observed in the incidence of hypotension, myocardial infarction, and all-cause mortality between the dexmedetomidine and placebo groups. Among elderly patients after noncardiac surgery, the prophylactic use of dexmedetomidine, compared with the use of placebo, was related to a decline in the incidence of POD.

Partial Text

Delirium is usually characterized as a multifactorial syndrome of acute attention and cognitive disorders; delirium is also a common, serious, underrecognized, and even lethal condition, especially for geriatric patients [1]. Delirium is associated with an elevated risk of mortality, complication morbidity, and dementia, an extended length of hospital stay, and a worsening in health-related quality of life [2–6]. The prevalence of postoperative delirium (POD) in elderly patients after noncardiac surgery is approximately 13% to 50% [1]. To decrease the incidence and adverse outcomes associated with delirium, multicomponent nonpharmacologic approaches that help control multiple risk factors of delirium are recommended [7, 8]. However, to date, the use of pharmacologic intervention to prevent delirium remains controversial [1, 8–11].

The meta-analysis was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria [17]. The protocol of our review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (registration no. CRD42018105508).

The meta-analysis incorporated six RCTs [27–32] that met the inclusion criteria and included 2102 elderly patients in total. The main conclusion of this review was that elderly patients who underwent noncardiac surgery and received dexmedetomidine intervention had a significantly lower occurrence of POD than those who received placebo. Even though dexmedetomidine could increase the risk of bradycardia, the drug might reduce the occurrence of tachycardia, hypertension, stroke, and hypoxaemia; no significant differences were discovered in the incidence of hypotension, myocardial infarction, and all-cause mortality between the dexmedetomidine and placebo groups.

In summary, the results of our review indicated that perioperative prophylactic intervention with dexmedetomidine, compared with placebo, could significantly reduce the prevalence of POD, tachycardia, hypertension, and hypoxaemia in elderly patients following non-cardiac surgery. However, the use of dexmedetomidine was associated with an elevated risk of bradycardia. Additional high-quality, large-scale multicenter RCTs are still warranted for the purpose of exploring the optimal dose and timing of dexmedetomidine on POD prevention among the elderly population after noncardiac surgery.