A commentary on "Effect of intraoperative dexmedetomidine on postoperative mental health in cardiac surgery: a randomized controlled trial".

Dear Editor, By conducting a randomized controlled trial in 200 adult participants who underwent elective cardiac surgery, Hao et al[1] demonstrated that intraoperative dexmedetomidine with a loading dose of 0.6 μg/kg within 10 min followed by continuous infusion at a rate of 0.4 μg/kg/h significantly decreased the rates of depression, anxiety, delirium, sleep disturbance, and pain at postoperative day 7, with an improved quality of life. Given that postoperative mental disorders can significantly delay function recovery, worsen outcomes, increase healthcare costs, and decrease patient satisfaction following cardiac surgery, their findings have potentially clinical implications. As a randomized controlled trial determining the effects of an intervention on postoperative mental health and clinical benefits of cardiac surgical patients, however, we have several questions about the methodology and results of this study that need further discussion with the authors. First, postoperative depression, anxiety, and sleep disturbance were assessed by the recognized rating scales, such as the Patient Health Questionnaire-9 (PHQ-9) scale, Generalized Anxiety Disorder-7 (GAD-7) scale, Pittsburgh Sleep Quality Index (PSQI), and others. Hao et al[1] did not provide the preoperative values of these scores, although participants with a history of psychiatric/neurological disorders were excluded from the study. Available evidence indicates that preoperative insomnia determined by the PSQI, and clinically relevant depressive and anxiety symptoms assessed by the PHQ-9 and GAD-7 scales are common among patients undergoing cardiac and non-cardiac surgery and these mental disorders before surgery can frequently be worsened after surgery[2–4]. Furthermore, most of the participants suffered from many preoperative comorbidities such as diabetes, hypertension, and coronary heart disease. The incidence of each comorbidity was not significantly different between groups, but Hao et al[1] did not clearly describe if total comorbidity burden assessed by the recognized scoring tools, for example, the Charlson comorbidity index, was comparable between groups. It has been shown that an increased preoperative comorbidity burden is associated with the occurrence of new-onset depression following surgery[5]. Thus, we are concerned that any significant imbalance in the above-mentioned preoperative factors would have biased the primary and secondary outcomes of this study. Second, it was unclear why pain assessment was started only at postoperative day 3. Importantly, the rate of severe pain at rest was up to 18–27% at postoperative day 3 and 14–24% at postoperative day 7, which were significantly increased in the Placebo group. However, in the methods, Hao et al[1] did not provide the details of the postoperative analgesia scheme and did not clearly describe whether the same postoperative pain management scheme and analgesia objective were conducted in two groups. It must be noted that postoperative pain not only can cause sleep disorders[6,7] and decrease patients’ mobility, self-care ability, and usual activities[8], but also may facilitate the occurrence of depression, anxiety, and delirium after surgery[9,10]. In fact, pain/discomfort, mobility, self-care ability, usual activities, and anxiety/depressive symptom all are the scoring items of the EQ-5D-5L Scale used in this study, a most commonly used scoring system assessing postoperative quality of life[11]. Accordingly, we argue that poor postoperative pain control in the Placebo group should be attributable to increased rates of depression, anxiety, delirium, and sleep disturbance and worsened quality of life in the early postoperative period. Third, most of the depression and anxiety attacks at postoperative day 7 were actually mild. Both the rates of mild depression and anxiety, and sleep disturbance at postoperative day 7 and delirium at postoperative day 1 were evidently reduced with intraoperative dexmedetomidine, but two groups were comparable with respect to the rates of moderate and severe depression and anxiety at postoperative day 7 and the rates of depression, anxiety, and sleep disorders at postoperative day 30. Unfortunately, Hao et al[1] did not report the duration of observed postoperative mental disorders and their related treatment needs, albeit only moderate or severe postoperative mental disorders with a long duration or treatment needs are generally considered as clinically significant. Especially, there were no statistically significant differences in the clinically important endpoints, including time to extubation, ICU duration, rates of postoperative complications, and length of hospital stay. In these cases, it is a dilemma for the readers in determining if intraoperative dexmedetomidine can really benefit cardiac surgical patients by decreasing delirium, mild depression, and anxiety attacks and improving sleep quality in the early postoperative period. Finally, we ensure that our article is compliant with the TITAN Guidelines 2025, as shown in the TITAN Guideline Checklist 2025[12].