Determining influences of intraoperative s-ketamine on postoperative delirium and cognitive function: methodology is important.
Dan-Feng Wang, Fei Gao, Fu-Shan Xue
Journal of cardiothoracic surgery December 31, 2024 DOI: 10.1186/s13019-024-03242-4 via PubMed
Summary
AI-generated from the abstractThis letter raises methodological concerns about a study claiming that low-dose S-ketamine during thoracic surgery reduces postoperative delirium and cognitive dysfunction in older adults. The authors point out that the study lacked details on how often delirium was monitored each day, relied solely on the Confusion Assessment Method for screening, did not report factors contributing to delirium in the ICU, and used a non-standard definition for cognitive impairment. They note inconsistencies with a recent randomized trial and argue these issues need clarification before accepting the conclusions.
Study at a glance
| Characteristics | Letter to the editor Randomized Peer reviewed |
|---|---|
| Topics | Ketamine |
| Keywords | Anesthesia Cognitive function Surgical outcomes Brain health |
| Key finding | The letter identifies several methodological flaws in a retrospective study on low-dose S-ketamine, including inadequate delirium monitoring, sole use of the Confusion Assessment Method, and non-standard cognitive impairment definitions, which undermine the claimed neuroprotective effect. |
Abstract
The letter to the editor was written in response to the recent article by Wang et al. "The influence of low-dose s-ketamine on postoperative delirium and cognitive function in older adults undergoing thoracic surgery", which is published in Journal of Cardiothoracic Surgery. 2024; 19(1):324. This article concludes that intravenous low-dose S-ketamine during thoracic surgery in older patients significantly reduces the incidences of postoperative delirium and cognitive dysfunction, indicating a potential neuroprotective effect of intraoperative low-dose S-ketamine. In view to the retrospective nature of this study and their inconsistent findings with the results of a recent randomized controlled trial performed in patients undergoing non-cardiac thoracic surgery, we believe that several methodological issues and potential confounders in this study deserve further clarification and discussion before accepting their conclusions. Our main concerns include lacking the times and number of delirium monitoring per postoperative day, alone use of the Confusion Assessment Method form for delirium screening, not providing the factors related to the occurrence of postoperative delirium in the ICU stay, and application of a non-standard definition for postoperative cognitive impairment. We believe that clarification of these issues is useful for improving the transparency of their methodology and facilitating the interpretation of their results.