Patient Factors and Subanesthetic Ketamine in PACU: Clinical Insights

Patient Factors Associated With Subanesthetic Ketamine in PACU

The September 2026 PubMed study (PMID: 42773015) identifies specific patient characteristics that correlate with the use of subanesthetic-dose ketamine infusions in the postanesthesia care unit (PACU). This research provides actionable data for clinicians considering ketamine for perioperative pain or mood management, highlighting which patients are most likely to receive ketamine in real-world hospital settings. The study, conducted in a large academic medical center, analyzed perioperative records to determine demographic and clinical predictors of ketamine administration at subanesthetic doses during the immediate postoperative period.

Mechanisms and Clinical Context for Ketamine Use

Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has established roles in anesthesia, but its subanesthetic use for pain and mood modulation is increasingly common in perioperative settings. The study found that younger age, higher preoperative pain scores, opioid tolerance, and certain psychiatric comorbidities (such as depression or anxiety) were independently associated with receiving subanesthetic ketamine in the PACU. These findings suggest that clinicians are selectively targeting patients with higher risk profiles for difficult postoperative pain or mood disturbances, leveraging ketamine’s dissociative and analgesic properties. Importantly, the study also notes that institutional protocols and provider preferences significantly influence patient selection, a factor often underappreciated in previous literature.

Policy and Research Implications

The identification of patient factors linked to subanesthetic ketamine use has several implications for clinical practice, research design, and hospital policy. For clinicians, these data support more nuanced risk stratification and patient selection, potentially improving outcomes and resource allocation. For researchers, understanding real-world prescribing patterns can inform the design of future randomized controlled trials (RCTs), ensuring that study populations reflect those most likely to benefit or experience adverse effects. Hospitals and health systems may use these findings to refine perioperative pain protocols, standardize ketamine administration criteria, and develop targeted safety monitoring strategies. Notably, the study’s methodology—leveraging large-scale electronic health record (EHR) data—demonstrates a scalable approach for ongoing pharmacovigilance and protocol optimization, a detail often overlooked in policy discussions.

Risks, Unknowns, and Safety Considerations

While subanesthetic ketamine is generally well-tolerated, its use in vulnerable populations raises important safety questions. The study reports that patients with psychiatric comorbidities and opioid tolerance—groups at higher risk for adverse events—are more likely to receive ketamine, underscoring the need for vigilant monitoring. Known risks include dissociation, hemodynamic instability, and emergence phenomena. Long-term neuropsychiatric effects remain insufficiently studied, particularly in perioperative and repeated-use contexts. The absence of standardized dosing protocols across institutions further complicates safety assessments. The authors highlight that, despite growing off-label use, robust data on optimal dosing, patient selection, and monitoring are still lacking, and recommend that future trials incorporate stratified safety endpoints based on the identified risk factors.

Looking Forward: Toward Evidence-Based Perioperative Ketamine Protocols

This study advances the field by providing concrete, data-driven guidance for perioperative ketamine use, but also reveals persistent gaps in evidence and standardization. As ketamine’s therapeutic applications expand beyond anesthesia, institutions and regulators will need to balance innovation with patient safety, particularly for high-risk groups. Future research should prioritize prospective trials that stratify by the identified patient factors, and health systems should consider integrating EHR-driven decision support tools to guide ketamine administration. Ultimately, translating these findings into practice will require collaboration between clinicians, researchers, and policymakers to ensure that the benefits of subanesthetic ketamine are realized without compromising patient safety.

How we research: This article was written and reviewed by Dr. Alex R. Kim, MD, MPH, clinical pharmacologist and policy analyst, on 2026-09-25. Primary source: PubMed PMID: 42773015.