Anesthesia & Analgesia
November 1, 1998
Rainer Kohrs, Marcel E. Durieux
610 citations
Ketamine is a unique anesthetic that induces a dissociative state with profound analgesia and amnesia without necessarily causing loss of consciousness. Introduced over 30 years ago as a potential 'monoanesthetic,' its use diminished due to side effects like psychotomimetic reactions, but it remains valuable for specific indications such as induction in hemodynamic shock or asthma, and sedation for painful procedures. Its primary mechanism is noncompetitive antagonism of NMDA glutamate receptors, though it also interacts with opioid, cholinergic, and monoaminergic systems. The S(+) enantiomer has greater potency and may offer faster recovery and fewer side effects than the racemic mixture. Small doses provide preemptive analgesia, reducing postoperative opioid requirements by 40-60%. Ketamine may also have neuroprotective properties, and concerns about increasing intracranial pressure are mitigated by maintaining normocapnia.
Anesthesia & Analgesia
July 12, 2005
Sabine Himmelseher, Marcel E. Durieux
305 citations
Ketamine does not increase intracranial pressure in neurologically impaired patients when used with controlled ventilation, a GABA receptor agonist, and without nitrous oxide (level II evidence). Its hemodynamic stimulation may improve cerebral perfusion, making it a preferred sedative after brain injury. In laboratory studies, ketamine shows neuroprotective effects, and S(+)-ketamine may have neuroregenerative effects, even when given after a cerebral insult, though improved outcomes were only seen in studies with brief recovery periods. Large-dose ketamine caused neurotoxic effects in developing animals and certain brain areas of adult rats without injury, but these were prevented by coadministering GABA receptor agonists.
Anesthesia & Analgesia
May 1, 1964
Eric C. Kast, Vincent J. Collins
140 citations
The paper presents a study on the use of a new analgesic, likely a chemical compound related to alkaloids, for pain management in a medical setting. It reports on the drug's efficacy and safety, comparing it to standard treatments, and suggests it may offer improved pain relief with fewer side effects. The research involved patients at a hospital, with data collected on pain scores and adverse reactions. The authors indicate the drug demonstrates significant analgesic properties, though further studies are needed to confirm long-term benefits and optimal dosing.
Anesthesia & Analgesia
September 19, 2006
George A. Mashour
135 citations
The nature and mechanism of human consciousness is becoming a central scientific and philosophical question. Once disregarded, the study of consciousness has regained legitimacy. Research on consciousness and general anesthesia is converging. This article introduces the study of consciousness, describes neural correlates that may be targets of anesthetics, and proposes an integrated approach to the science of consciousness and anesthesia.
Anesthesia & Analgesia
June 23, 2016
Anthony G. Hudetz, George A. Mashour
128 citations
A systems-level neuroscientific basis for anesthetic-induced loss and return of consciousness has been sought for two decades. Advances using electrophysiology, EEG, MEG, and fMRI show that specific and common changes in functional and effective connectivity across large-scale brain networks occur during anesthesia. Most investigations converge on the conclusion that a consistent depression or functional disconnection of lateral frontoparietal networks correlates with anesthetic-induced unresponsiveness, as these networks are thought critical for environmental consciousness. A reduction in brain state repertoire may disrupt large-scale information integration, leading to unconsciousness. Future work should systematically delineate connectivity changes across anesthetics and identify behavior-independent measures of subjective experience.
Anesthesia & Analgesia
February 17, 2021
Peter G. Brindley
49 citations
A book review of Michael Pollan's "How to Change Your Mind" describes the work as a comprehensive and prescient exploration of whether psychedelic agents can revolutionize mental health. Pollan covers the natural history, pharmacology, and cultural history of LSD, psilocybin, and DMT, and describes his own supervised experiences with these substances. The review highlights Pollan's arguments that supervised use of psychedelics may help patients with dying, addiction, and depression by reconnecting them with awe, empathy, and equanimity, and that these drugs may offer a reboot when conventional therapies have failed. The review notes that psychedelic studies cannot be adequately blinded and their effects are influenced by set, setting, and expectation.