Dissociative and analgesic properties of ketamine are independent and unaltered by sevoflurane general anesthesia
Eunice Y. Hahm, Shubham Chamadia, J. Locascio, J. Pedemonte, Jacob Gitlin, Jennifer Mekonnen, R. Ibala, Breanna R. Ethridge, Katia Colon, J. Qu, O. Akeju
PAIN Reports June 3, 2021 DOI: 10.1097/pr9.0000000000000936 via Semantic Scholar
Summary
Ketamine given during general anesthesia reduces pain intensity by 3 points and increases dissociation scores by 17.8 points, but these two effects are independent: the pain reduction does not depend on dissociation. This suggests that ketamine's analgesic and dissociative properties involve separate brain circuits, even under general anesthesia, and that ketamine might be developed into a more targeted pain treatment without causing dissociation.
Study at a glance
| Characteristics | Randomized controlled cross-over study Open-label Peer reviewed |
|---|---|
| Sample size | 12 |
| Population | Healthy subjects |
| Keywords | Medicine |
| Citations | 6 |
| Key finding | Ketamine's analgesic and dissociative effects are separable under general anesthesia, as dissociation did not mediate the reduction in pain intensity or quality. |
Abstract
Ketamine-induced dissociation and analgesia are independent and robust to general anesthesia neural circuit alterations, suggesting that ketamine can be refined into a targeted pain therapeutic. Abstract Introduction: Ketamine, an anesthetic adjunct, is routinely administered as part of a balanced general anesthetic technique. We recently showed that the acute analgesic and dissociation properties of ketamine are separable to suggest that distinct neural circuits underlie these states. Objective: We aimed to study whether this finding is robust to the substantial neural circuit alterations associated with general anesthesia. Methods: We conducted a single-site, open-label, randomized controlled, cross-over study of sevoflurane and sevoflurane-plus-ketamine (SK) general anesthesia in healthy subjects (n = 12). Before and after general anesthesia, we assessed precalibrated cuff pain intensity and nociceptive pain quality as well as dissociation using the Clinician-Administered Dissociative States Scale (CADSS). For statistical inference, we ran a variation of backward elimination repeated-measures analysis of covariance. Models with CADSS as a covariate term were used to assess whether dissociation mediated the effect of ketamine on pain intensity and quality. Results: Sevoflurane-plus-ketamine general anesthesia was associated with a significant (P = 0.0002) pain intensity decline of 3 (SE, 0.44). There was an order effect for dissociation such that SK was associated with a significant (P = 0.0043) CADSS increase of 17.8 (3.2) when the SK treatment came first. When the pain intensity model was reanalyzed with CADSS as an additional covariate, the effect of CADSS was not significant. These results were also conserved for pain quality. Conclusions: Our findings suggest that the analgesic and dissociation properties of ketamine remain separable despite general anesthesia. Thus, ketamine may be used as a probe to advance our knowledge of dissociation independent pain circuits.