Effect of Ephedrine versus Phenylephrine on Postoperative Delirium in Elderly Patients Undergoing Total Hip or Knee...

Postoperative delirium (POD) is a common complication in elderly patients. Since ephedrine and phenylephrine have different effects on cerebral perfusion and oxygenation, this randomized controlled trial aimed to compare the impact of these two drugs on the incidence of POD in elderly patients undergoing total hip or knee arthroplasty under general anesthesia.

A total of 142 elderly patients, aged 65 to 80 years, who underwent elective surgery for total hip or knee arthroplasty were randomly assigned to either the ephedrine group (Group E) or the phenylephrine group (Group P). POD was evaluated using the 3-minute Diagnostic Confusion Assessment Method (3D-CAM). The primary outcome was the incidence of POD within three days after surgery, while secondary outcomes included the subtypes of delirium, intraoperative hemodynamic changes, intraoperative analgesic consumption, and the occurrence of intraoperative and postoperative adverse events.

Delirium occurred in 5 out of 65 cases (7.7%) in Group E and in 15 out of 67 cases (22.4%) in Group P (relative risk [RR], 0.344; 95% confidence interval [CI], 0.132 to 0.891; p = 0.019). Compared to Group P, Group E exhibited a significantly lower incidence of intraoperative bradycardia (RR, 0.241; 95% CI, 0.114 to 0.508; p < 0.001). However, Group E also demonstrated a significantly higher consumption of intraoperative opioids (median difference [MD], 23.0; 95% CI, 2.0 to 25.0 mg; p = 0.020). Notably, despite the higher intraoperative opioid consumption in Group E, there was no statistically significant difference in postoperative pain scores between the two groups (p > 0.05). Additionally, there were no statistically significant differences between the two groups in other indicators, including intraoperative hemodynamic changes and the incidence of postoperative nausea and vomiting (p > 0.05).

In conclusion, among elderly patients undergoing hip or knee arthroplasty, the use of ephedrine to correct intraoperative hypotension was associated with a reduced incidence of POD within three days compared to phenylephrine. However, the absence of cerebral oxygen saturation monitoring and the limited follow-up period of only three days for POD assessment represent significant limitations. These factors should be carefully considered when interpreting our results.