Authors: Wang Y et al.
Anesthesia & Analgesia, 2026.
Analytical Concerns Regarding the Association Between Neuromuscular Blockade and Its Reversal With Postoperative Delirium in Older Patients.
This letter to the editor discusses methodological concerns related to a recently published study examining the relationship between neuromuscular blockade (NMB), its pharmacologic reversal, and postoperative delirium (POD) in older surgical patients. The original study analyzed registry data and suggested possible associations between neuromuscular blockade strategies and delirium risk.
The authors of this correspondence acknowledge the importance of the original work and commend the investigators for performing a large registry analysis exploring modifiable anesthetic factors associated with postoperative delirium. However, they raise several concerns regarding the analytical framework and interpretation of results.
First, the authors highlight the absence of postoperative pain and analgesic management variables in the analysis. Postoperative pain and opioid exposure are well-established contributors to delirium, particularly in elderly patients. Failure to adjust for these factors could introduce residual confounding, making it difficult to determine whether neuromuscular blockade or pain management strategies are responsible for the observed association with delirium. The authors suggest that future analyses incorporate postoperative pain scores and analgesic medication data to better understand potential mediating pathways.
Second, the letter points out limitations in how delirium outcomes were characterized. In the referenced study, postoperative delirium was treated as a binary outcome—either present or absent. The authors argue that delirium is a heterogeneous condition that varies substantially in severity, duration, and clinical trajectory. For example, transient delirium and persistent delirium may have very different prognostic implications.
They recommend using validated delirium assessment tools that allow more granular outcome measures, such as:
• Confusion Assessment Method Severity (CAM-S)
• Memorial Delirium Assessment Scale (MDAS)
These tools capture delirium severity and could provide more clinically meaningful insights than simple binary classification.
The authors conclude that these methodological considerations highlight opportunities for future research to better integrate perioperative management strategies into analyses of neuromuscular blockade and delirium outcomes. Improved analytic approaches may enhance risk stratification and help identify preventive strategies for postoperative delirium in older adults.
Key Points
• A recent registry study examined the association between neuromuscular blockade, reversal agents, and postoperative delirium.
• This letter highlights potential methodological limitations in that analysis.
• Postoperative pain and opioid use were not included in the original study but are important delirium risk factors.
• Delirium was treated as a binary outcome rather than being stratified by severity or duration.
• Use of validated severity scales such as CAM-S or MDAS could improve clinical relevance of future research.
Thank you to Anesthesia & Analgesia for allowing us to summarize and share this article.