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Background Delirium is a critical postoperative complication in older patients. Based on the hypothesis that intraoperative dexmedetomidine sedation would lower postoperative delirium than propofol sedation would, the authors compared the incidence of postoperative delirium in older adults, using the mentioned sedatives. Methods This double-blinded, randomized controlled study included 748 patients, aged 65 yr or older, who were scheduled for elective lower extremity orthopedic surgery, between June 2017 and October 2021. Patients were randomized equally into two groups in a 1:1 ratio according to the intraoperative sedative used (dexmedetomidine vs. propofol). The postoperative delirium incidence was considered the primary outcome measure; it was determined using the confusion assessment method, on the first three postoperative days. The mean arterial pressure and heart rate were evaluated as secondary outcomes. Results The authors enrolled 732 patients in the intention-to-treat analyses. The delirium incidence was lower in the dexmedetomidine group than in the propofol group (11 [3.0%] vs. 24 [6.6%]; odds ratio, 0.42; 95% CI, 0.201 to 0.86; P = 0.036). During sedation, the mean arterial pressure (median [interquartile range] mmHg) was higher in the dexmedetomidine group (77 [71 to 84]) than in the propofol group (74 [69 to 79]; P < 0.001); however, it significantly fell lower (74 [68 to 80]) than that of the propofol group (80 [74 to 87]) in the postanesthesia care unit (P < 0.001). Lower heart rates (beats/min) were recorded with the use of dexmedetomidine than with propofol, both during sedation (60 [55 to 66] vs. 63 [58 to 70]) and in the postanesthesia care unit (64 [58 to 72] vs. 68 [62–77]; P < 0.001). Conclusions Dexmedetomidine showed a lower incidence of postoperative delirium than propofol in healthy older adults undergoing lower extremity orthopedic surgery. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

The present study aimed to investigate the incidence of preoperative ionized hypomagnesemia and compare with that of total hypomagnesemia.This prospective observational study included 536 patients aged20 years who were scheduled for elective surgery. Total and ionized magnesium levels were evaluated before and after the surgery. Based on these levels, patients were classified into the following groups: ionized hypo- (0.42 mmol/L), normo- (0.42-0.59 mmol/L) and hypermagnesemia (0.59 mmol/L), as well as total hypo- (1.9 mg/dL[0.78 mmol/L]), normo- (1.9-2.7 mg/dL[0.78-1.11 mmol/L]) and hypermagnesemia (2.7 mg/dL [1.11 mmol/L]). The primary objective was to establish the incidence of preoperative ionized hypomagnesemia.There was a marked difference between the incidence of preoperative ionized and total hypomagnesemia (28% vs. 19%; p0.001). The postoperative values of ionized magnesium, ionized calcium, and albumin were significantly lower than the respective preoperative values (p0.001 for all three variables).The incidence of hypomagnesemia, determined by ionized magnesium concentration, was higher than that determined by total magnesium concentration.