2025/09/02 by Byung‐Moon Choi · 1 voice
Medicine · #Cardiac, Anesthesia and Surgical Outcomes #Enhanced Recovery After Surgery #Intensive Care Unit Cognitive Disorders
paper · pdf · doi:10.1111/anae.16766
openalex publication_date 2025/09/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
We thank Wang et al. [1] and Xue et al. [2] for their thoughtful comments on our recent study [3]. It is important to account for the many factors that may influence the development of postoperative delirium. As described in our Methods, patients with psychiatric conditions such as depression or neurological disorders were not studied. Pre-operative variables such as anxiety, sleep quality and educational level were not assessed. However, because block randomisation was used, it is unlikely that these unmeasured factors differed significantly between the two groups. The incidence of postoperative nausea and vomiting differs based on the type of surgery, so a homogeneous surgical population was selected to minimise potential confounders. In South Korea, due to the nationwide health insurance system and government-supported biennial screening endoscopy for individuals aged > 40 years, a high proportion of patients undergo gastrectomy at an early stage of gastric cancer. As a result, the need for nasogastric tube insertion due to gastric outlet obstruction is uncommon in clinical practice. While regional blocks are an effective analgesic method following gastrectomy, they are not used commonly because of institutional limitations. Given that the primary objective of this study was to compare the incidence of postoperative delirium between remimazolam and propofol, and considering that both groups received an identical postoperative analgesic protocol, it is unlikely that postoperative pain exerted a significant differential effect on delirium incidence. Although individualised intra-operative blood pressure adjustment is ideal, it is not standard practice. Since our study did not focus primarily on haemodynamic stability, we managed blood pressure according to usual protocols. Instead of comparing vasopressor doses, we assessed how well systolic blood pressure was maintained, providing raw data (see online Supporting Information Figure S1 in [3]) and normalised AUC comparisons. No significant difference was found between groups, suggesting minimal impact on delirium incidence. We re-analysed our data to explore the potential influence of anaemia, hypoalbuminaemia and chronic renal failure on the incidence of postoperative delirium. Anaemia was defined according to World Health Organization criteria, that is, haemoglobin < 130 g.l-1 in men and < 120 g.l-1 in women, and hypoalbuminaemia as serum albumin < 35 g.l-1. Chronic renal failure was defined as an estimated glomerular filtration rate of < 60 ml.min-1.1.73 m-2. The prevalence did not differ significantly between groups: anaemia (remimazolam n = 89, propofol n = 78, χ2 test, p = 0.323); hypoalbuminaemia (remimazolam n = 28, propofol n = 40, χ2 test, p = 0.146); and chronic kidney disease (remimazolam n = 33, propofol n = 26, χ2 test, p = 0.401). Although it is desirable to assess for delirium repeatedly due to its fluctuating nature, there is no universally accepted standard for the optimal frequency of daily assessments. This issue was acknowledged as a limitation in the Discussion section of our study [3]. In addition to the formal confusion assessment method (CAM) postoperatively, we also reviewed patients' medical records to capture any documented signs of delirium. Importantly, the 24-h CAM assessment was not limited to evaluating a single time point but was intended to reflect the presence of delirium throughout the entire 24-h postoperative period. Therefore, we believe the likelihood of underdiagnosing delirium was low. Regarding the timing of quality of recovery assessment, we selected the 24-h postoperative time-point based on the pharmacokinetics of remimazolam, which has a terminal elimination half-life of approximately 37–53 min [4]. It is generally accepted that a drug is effectively cleared from the body after four to five times its elimination half-life. Thus, we considered 24 h to be a clinically appropriate interval for assessing recovery. Whether routine evaluation of recovery quality at 48 h is necessary for short-acting drugs such as remimazolam remains uncertain.