The Emerging Role of LHb CaMKII in the Comorbidity of Depressive and Alcohol Use Disorders.

Depressive disorders and alcohol use disorders are widespread among the general population and are significant public health and economic burdens. Alcohol use disorders often co-occur with other psychiatric conditions and this dual diagnosis is called comorbidity. Depressive disorders invariably contribute to the development and worsening of alcohol use disorders, and vice versa. The mechanisms underlying these disorders and their comorbidities remain unclear. Recently, interest in the lateral habenula, a small epithalamic brain structure, has increased because it becomes hyperactive in depression and alcohol use disorders, and can inhibit dopamine and serotonin neurons in the midbrain reward center, the hypofunction of which is believed to be a critical contributor to the etiology of depressive disorders and alcohol use disorders as well as their comorbidities. Additionally, calcium/calmodulin-dependent protein kinase II (CaMKII) in the lateral habenula has emerged as a critical player in the etiology of these comorbidities. This review analyzes the interplay of CaMKII signaling in the lateral habenula associated with depressive disorders and alcohol use disorders, in addition to the often-comorbid nature of these disorders. Although most of the CaMKII signaling pathway's core components have been discovered, much remains to be learned about the biochemical events that propagate and link between depression and alcohol abuse. As the field rapidly advances, it is expected that further understanding of the pathology involved will allow for targeted treatments.

Ketamine-A Narrative Review of Its Uses in Medicine.

One of the most fascinating drugs in the anesthesiologist's armament is ketamine, an N-methyl-D-aspartate receptor antagonist with a myriad of uses. The drug is a dissociative anesthetic and has been used more often as an analgesic in numerous hospital units, outpatient pain clinics, and in the prehospital realm. It has been used to treat postoperative pain, chronic pain, complex regional pain syndrome, phantom limb pain, and other neuropathic conditions requiring analgesia. Research has also demonstrated its efficacy as an adjunct in psychotherapy, as a treatment for both depression and posttraumatic stress disorder, as a procedural sedative, and as a treatment for respiratory and neurologic conditions. Ketamine is not without its adverse effects, some of which can be mitigated with certain efforts. Such effects make it necessary for the clinician to use the drug only in situations where it will provide the greatest benefit with the fewest adverse effects. To the best of our knowledge, none of the reviews regarding ketamine have taken a comprehensive look at the drug's uses in all territories of medicine. This review will serve to touch on its chemical data, pharmacokinetics and pharmacodynamics, medical uses, and adverse effects while focusing specifically on the drugs usage in anesthesia and analgesia.

Ropivacaine 0.1% versus 0.2% for continuous lumbar plexus nerve block infusions following total hip arthroplasty: a randomized, double blinded study.

OBJECTIVE: Continuous lumbar plexus blocks provide excellent analgesia for total hip arthroplasty (THA), but their utility has been questioned as they may increase motor weakness. The aim of this study was to compare the efficacy of two different concentrations of ropivacaine on both postoperative analgesia and motor function. METHODS: Thirty patients were examined in this prospective, single center, double-blinded, parallel group, comparative, randomized controlled trial in patients undergoing primary THA. Lumbar plexus catheters were inserted preoperatively. After surgery, patients were randomly assigned to receive an infusion of ropivacaine at a concentration of either 0.1% (group 0.1%) or 0.2% (group 0.2%) at a standardized volume of 7 mL per hour for 24 hours. Patients were also given free access to patient-controlled analgesia hydromorphone for 24 hours, supplemental intravenous (IV) opiates, and boluses of their assigned local anesthetic concentration via the lumbar plexus catheter. The primary endpoint was total hydromorphone consumption in 24 hours. Secondary endpoints included pain scores, sensory and motor function, and patient satisfaction. RESULTS: There was no significant difference in hydromorphone consumption in the first 24 hours postoperatively (mean [95% confidence interval]) between group 0.1% (8.02 mg [6.02-10.02]) and group 0.2% (8.21 mg [5.75-10.69], P = 0.90). The volume of local anesthetic received, pain scores, sensory and motor function, and patient satisfaction did not vary between groups. CONCLUSIONS: Following primary THA, lumbar plexus perineural infusion of 0.1% ropivacaine provided similar benefits for postoperative analgesia and functional recovery as 0.2% ropivacaine.

Multiorganizational consensus to define guiding principles for perioperative pain management in patients with chronic pain, preoperative opioid tolerance, or substance use disorder.

Significant knowledge gaps exist in the perioperative pain management of patients with a history of chronic pain, substance use disorder, and/or opioid tolerance as highlighted in the US Health and Human Services Pain Management Best Practices Inter-Agency Task Force 2019 report. The report emphasized the challenges of caring for these populations and the need for multidisciplinary care and a comprehensive approach. Such care requires stakeholder alignment across multiple specialties and care settings. With the intention of codifying this alignment into a reliable and efficient processes, a consortium of 15 professional healthcare societies was convened in a year-long modified Delphi consensus process and summit. This process produced seven guiding principles for the perioperative care of patients with chronic pain, substance use disorder, and/or preoperative opioid tolerance. These principles provide a framework and direction for future improvement in the optimization and care of 'complex' patients as they undergo surgical procedures.

A multisociety organizational consensus process to define guiding principles for acute perioperative pain management.

The US Health and Human Services Pain Management Best Practices Inter-Agency Task Force initiated a public-private partnership which led to the publication of its report in 2019. The report emphasized the need for individualized, multimodal, and multidisciplinary approaches to pain management that decrease the over-reliance on opioids, increase access to care, and promote widespread education on pain and substance use disorders. The Task Force specifically called on specialty organizations to work together to develop evidence-based guidelines. In response to this report's recommendations, a consortium of 14 professional healthcare societies committed to a 2-year project to advance pain management for the surgical patient and improve opioid safety. The modified Delphi process included two rounds of electronic voting and culminated in a live virtual event in February 2021, during which seven common guiding principles were established for acute perioperative pain management. These principles should help to inform local action and future development of clinical practice recommendations.

EXPAREL® (Long-Acting Liposomal Bupivacaine) Use for Popliteal Nerve Block in Postoperative Pain Control after Ankle Fracture Fixation.

EXPAREL® has been used successfully to prolong postoperative pain control when applied as a wound infiltrate. EXPAREL® has not yet been approved for use in regional anesthesia to prolong postoperative pain control. We conducted a clinical case series of 4 patients using EXPAREL® for sciatic blocks via the popliteal fossa approach. Our results suggested that there is a large degree of variability in response to the medication. These inconsistent results and the possibility of bimodal kinetics creating analgesic gaps as seen in two of our patients indicate that more studies with larger sample size are needed to better characterize these phenomena and determine if more consistent results can be obtained in a future clinical trial.

Steroid-Mediated Decrease in Blood Mesenchymal Stem Cells in Liver Transplant could Impact Long-Term Recovery.

Orthotopic liver transplant (OLT) remains the standard of care for end stage liver disease. To circumvent allo-rejection, OLT subjects receive gluococorticoids (GC). We investigated the effects of GC on endogenous mesenchymal stem (stromal) cells (MSCs) in OLT. This question is relevant because MSCs have regenerative potential and immune suppressor function. Phenotypic analyses of blood samples from 12 OLT recipients, at pre-anhepatic, anhepatic and post-transplant (2 h, Days 1 and 5) indicated a significant decrease in MSCs after GC injection. The MSCs showed better recovery in the blood from subjects who started with relatively low MSCs as compared to those with high levels at the prehepatic phase. This drop in MSCs appeared to be linked to GC since similar change was not observed in liver resection subjects. In order to understand the effects of GC on decrease MSC migration, in vitro studies were performed in transwell cultures. Untreated MSCs could not migrate towards the GC-exposed liver tissue, despite CXCR4 expression and the production of inflammatory cytokines from the liver cells. GC-treated MSCs were inefficient with respect to migration towards CXCL12, and this correlated with retracted cytoskeleton and motility. These dysfunctions were partly explained by decreases in the CXCL12/receptor axis. GC-associated decrease in MSCs in OLT recipients recovered post-transplant, despite poor migratory ability towards GC-exposed liver. In total, the study indicated that GC usage in transplant needs to be examined to determine if this could be reduced or avoided with adjuvant cell therapy.

Dexmedetomidine Attenuates Neurotoxicity Induced by Prenatal Propofol Exposure.

BACKGROUND: Anesthetic agents (eg, isoflurane, propofol) may cause neurodegeneration in the developing brains and impair animals' learning ability. Dexmedetomidine (DEX), a selective alpha 2-adrenoreceptor agonist, has antiapoptotic properties in several brain injury models. Here, we tested whether DEX can protect the brain from neurodegeneration in rats exposed to propofol in utero. MATERIALS AND METHODS: Fetal rats of embryonic day 20 were exposed in utero for 1 hour to propofol anesthesia with DEX or saline, or no anesthesia (control). The fetal brains were harvested 6 hours later. Cleaved caspase-3 levels and the relative number of ionized calcium-binding adaptor molecule 1 (IBA1)-positive cells were assessed by Western blot and immunohistochemistry. Learning and memory functions of the offspring in a separate cohort were assessed at postnatal day 35 by using an 8-arm radial maze. RESULTS: Propofol anesthesia in pregnant rats augmented caspase-3 activation by 217% in the brain tissues of fetal rats and increased the number of IBA1-positive cells in the cortex by 40% and in the thalamus by 270%. Juvenile rats exposed prenatally to propofol were not different than controls on spontaneous locomotor activity, but made more errors of omission and took longer to complete visiting all 8 arms on days 1, 2, and 3 across a 5-day test in the radial arm maze. This neurocognitive deficit was prevented by administration of DEX (5.0 µg/kg, IP), which also significantly inhibited propofol-induced caspase-3 activation and microglial response in the fetal brains. CONCLUSIONS: DEX attenuates neuronal injury induced by maternal propofol anesthesia in the fetal brains, providing neurocognitive protection in the offspring rats.

Role of ketamine in acute postoperative pain management: a narrative review.

OBJECTIVES: The objective of this narrative review was to examine the usage of ketamine as a postoperative analgesic agent across a wide variety of surgeries. DESIGN: A literature search was performed using the phrases "ketamine" and "postoperative pain." The authors analyzed the studies that involved testing ketamine's effectiveness at controlling postoperative pain. Effectiveness was assessed through various outcomes such as the amount of opiate consumption, visual analog scale (VAS) pain scores, and persistent postoperative pain at long-term follow-up. RESULTS: While many different administration protocols were evaluated, delivering ketamine both as a pre- or perioperative bolus and postoperative infusion for up to 48 hours appeared to be the most effective. These effects are dose-dependent. However, a number of studies analyzed showed no benefit in using ketamine versus placebo for controlling postoperative pain. While ketamine is a safe and well-tolerated drug, it does have adverse effects, and there are concerns for possible neurotoxicity and effects on memory. CONCLUSIONS: In a number of limited situations, ketamine has shown some efficacy in controlling postoperative pain and decreasing opioid consumption. More randomized controlled trials are necessary to determine the surgical procedures and administrations (i.e., intravenous, epidural) that ketamine is best suited for.

Development of phantom limb pain after femoral nerve block.

Historically, phantom limb pain (PLP) develops in 50-80% of amputees and may arise within days following an amputation for reasons presently not well understood. Our case involves a 29-year-old male with previous surgical amputation who develops PLP after the performance of a femoral nerve block. Although there have been documented cases of reactivation of PLP in amputees after neuraxial technique, there have been no reported events associated with femoral nerve blockade. We base our discussion on the theory that symptoms of phantom limb pain are of neuropathic origin and attempt to elaborate the link between regional anesthesia and PLP. Further investigation and understanding of PLP itself will hopefully uncover a relationship between peripheral nerve blocks targeting an affected limb and the subsequent development of this phenomenon, allowing physicians to take appropriate steps in prevention and treatment.