Increasing alveolar ventilation enhances anaesthetic elimination and accelerates short-term recovery in obese patients.

Dexmedetomidine (DEX) was widely used in clinical work. However, the effectiveness of DEX on postoperative cognitive dysfunction (POCD) was still need to be confirmed. The aim of this meta-analysis was to explore whether DEX can reduce the incidence of POCD on the first day and seventh postoperative day. The results showed that lower incidence of POCD associated with DEX treatment on the first (odds ratio [OR]: 0.41; 95% confidence interval [CI]: 0.31-0.54) or seventh postoperative day (OR: 0.53; 95% CI: 0.36-0.77). Mini-Mental State Examination scores on the first (mean difference [MD]: 4.67; 95% CI: 1.72-7.63) and seventh postoperative days (MD: 3.71; 95% CI: 2.51-4.90) were higher in DEX use group than that in physiological saline group. Meanwhile, neuron-specific enolase (NSE; MD: −3.99; 95% CI: −6.20 to −1.78) and interleukin 6 (IL-6) levels (MD: −17.53; 95% CI: −21.51 to −13.54) on the first postoperative day in DEX group were lower than that in the physiological saline group. This meta-analysis suggested that DEX use could reduce the risk of POCD and the reduction in levels of NSE and IL-6 can improve long-term cognitive dysfunction and anti-inflammation.

Postoperative cognitive dysfunction (POCD), also named as postoperative neurocognitive disorder (NCD) (Evered, Silbert, & Knopman, 2018), is a highly prevalent disorder, especially in elderly patients, characterized by acute or persistent deficits in attention, concentration, learning, and memory following surgery, which can be detected by a battery of neuropsychological tests (Skvarc, Berk, & Byrne, 2018). POCD can prolong hospital stay, reduce quality of life, increase mortality, and aggravate the burden of public health, leading