Ketamine reduces mortality of severely burnt rats, when compared to midazolam plus fentanyl

Perioperative Ketamine and Cancer Recurrence: A Comprehensive Review

Cancer is a significant global health threat and a leading cause of death worldwide. Effective early-stage interventions, particularly surgery, can potentially cure many solid tumors. However, the risk of postoperative cancer recurrence remains high. Recent research highlights the influence of perioperative anesthetic and analgesic choices on the fate of residual cancer cells, potentially affecting recurrence risks. Among these agents, ketamine-a well-known anesthetic and analgesic-has garnered interest due to its antitumor properties, mainly through inhibiting the N-methyl-D-aspartate (NMDA) receptor found in various cancer tissues. Additionally, ketamine's potential immunomodulatory effects, given the expression of NMDA receptors on immune cells, suggest that it plays a significant role during the perioperative period. This review synthesizes current evidence on ketamine's impact on cancer cell biology, inflammation, immune modulation, and the role of the gut microbiota, proposing ketamine as a promising agent for enhancing oncological outcomes.

Acute (R,S)-Ketamine Administration Induces Sex-Specific Behavioral Effects in Adolescent but Not Aged Mice

(R,S)-ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist that was originally developed as an anesthetic. Most recently, (R,S)-ketamine has been used as a rapid-acting antidepressant, and we have reported that (R,S)-ketamine can also be a prophylactic against stress in adult mice. However, most pre-clinical studies have been performed in adult mice. It is still unknown how an acute (R,S)-ketamine injection influences behavior across the lifespan (e.g., to adolescent or aged populations). Here, we administered saline or (R,S)-ketamine at varying doses to adolescent (5-week-old) and aged (24-month-old) 129S6/SvEv mice of both sexes. One hour later, behavioral despair, avoidance, locomotion, perseverative behavior, or contextual fear discrimination (CFD) was assessed. A separate cohort of mice was sacrificed 1 h following saline or (R,S)-ketamine administration. Brains were processed to quantify the marker of inflammation Cyclooxygenase 2 (Cox-2) expression to determine whether the acute effects of (R,S)-ketamine were partially mediated by changes in brain inflammation. Our findings show that (R,S)-ketamine reduced behavioral despair and perseverative behavior in adolescent female, but not male, mice and facilitated CFD in both sexes at specific doses. (R,S)-ketamine reduced Cox-2 expression specifically in ventral CA3 (vCA3) of male mice. Notably, (R,S)-ketamine was not effective in aged mice. These results underscore the need for sex- and age-specific approaches to test (R,S)-ketamine efficacy across the lifespan.

Potential consequences of high-dose infusion of ketamine for refractory status epilepticus: case reports and systematic literature review

Our goal was to provide comprehensive data on the effectiveness of ketamine in refractory status epilepticus (RSE) and to describe the potential consequences of long-term ketamine infusion. Ketamine, an N-methyl D-aspartate (NMDA) receptor antagonist, blocks excitatory pathways contributing to ongoing seizure. While ketamine use is standard in anaesthetic induction, no definitive protocol exists for its use in RSE, and little is known about its adverse effects in long-term, high-dose administration. We present two cases of RSE that responded rapidly to ketamine infusion, both with fatal outcomes secondary to metabolic acidosis and cardiovascular collapse. We performed a systematic review of the application and consequences of ketamine use in RSE. PubMed, Ovid, MEDLINE and PMC were searched for articles describing ketamine treatment for RSE according to a predetermined search strategy and inclusion criteria. The systematic review revealed wide discrepancies in ketamine dosing (infusion maintenance dose range 0.0075-10.5 mg/kg/hour), but good outcomes in medically managed RSE (75% of studies reported moderate or complete seizure control in adults, 62.5% in paediatrics). Additionally, literature review elucidated a potentially causal relationship between prolonged ketamine infusion and both cardiovascular and metabolic dysregulation. Ketamine is effective in RSE by antagonising excitotoxic NMDA receptors. However, there is high variability in ketamine dosing and scarce data on its safety in long-term infusion. Metabolic acidosis and haemodynamic instability associated with the use of long-term, high-dose ketamine infusions must be of concern to clinicians administering ketamine to critically ill patients.

Combined hemorrhage/trauma models in pigs-current state and future perspectives

The majority of injury combinations in multiply injured patients entail the chest, abdomen, and extremities. Numerous pig models focus on the investigation of posttraumatic pathophysiology, organ performance monitoring and on potential treatment options. Depending on the experimental question, previous authors have included isolated insults (controlled or uncontrolled hemorrhage, chest trauma) or a combination of these injuries (hemorrhage with abdominal trauma, chest trauma, traumatic brain injury, and/or long-bone fractures). Combined trauma models in pigs can provide a high level of clinical relevance, when they are properly designed and mimicking the clinical situation. Most of these models focus on the first hours after trauma, to assess the acute sequel of traumatic hemorrhage. However, hemorrhagic shock and the associated mass transfusion are also major causes for organ failure and mortality in the later clinical course. Thus, most models lack information on the pathomechanisms during the late posttraumatic phase. Studying new therapies only during the early phase is also not reflective of the clinical situation. Therefore, a longer observation period is required to study the effects of therapeutic approaches during intensive care treatment when using animal models. These long-term studies of combined trauma models will allow the development of valuable therapeutic approaches relevant for the later posttraumatic course. This review summarizes the existing porcine models and outlines the need for long-term models to provide real effective novel therapeutics for multiply injured patients to improve organ function and clinical outcome.

Ketamine and peripheral inflammation

The old anesthetic ketamine has demonstrated interactions with the inflammatory response. This review intends to qualify the nature and the mechanism underlying this interaction. For this purpose, preclinical data will be presented starting with the initial works, and then, the probable mechanisms will be discussed. A summary of the most relevant clinical data will be presented. In conclusion, ketamine appears as a unique "homeostatic regulator" of the acute inflammatory reaction and the stress-induced immune disturbances. This is of some interest at a moment when the short- and long-term deleterious consequences of inadequate inflammatory reactions are increasingly reported. Large-scale studies showing improved patient's outcome are, however, required before to definitively assert the clinical reality of this positive effect.

Pro-con debate: etomidate or ketamine for rapid sequence intubation in pediatric patients

When caring for critically ill children, airway management remains a primary determinant of the eventual outcome. Airway control with endotracheal intubation is frequently necessary. Rapid sequence intubation (RSI) is generally used in emergency airway management to protect the airway from passive regurgitation of gastric contents. Along with a rapid acting neuromuscular blocking agent, sedation is an essential element of RSI. A significant safety concern regarding sedatives is the risk of hypotension and cardiovascular collapse, especially in critically ill patients or those with pre-existing comorbid conditions. Ketamine and etomidate, both of which provide effective sedation with limited effects on hemodynamic function, have become increasingly popular as induction agents for RSI. However, experience and clinical investigations have raised safety concerns associated with both etomidate and ketamine. Using a pro-con debate style, the following manuscript discusses the use of ketamine versus etomidate in RSI.

Cardiac arrest following ketamine administration for rapid sequence intubation

Given their relative hemodynamic stability, ketamine and etomidate are commonly chosen anesthetic agents for sedation during the endotracheal intubation of critically ill patients. As the use of etomidate has come into question particularly in patients with sepsis, due to its effect of adrenal suppression, there has been a shift in practice with more reliance on ketamine. However, as ketamine relies on a secondary sympathomimetic effect for its cardiovascular stability, cardiovascular and hemodynamic compromise may occur in patients who are catecholamine depleted. We present 2 critically ill patients who experienced cardiac arrest following the administration of ketamine for rapid sequence intubation (RSI). The literature regarding the use of etomidate and ketamine for RSI in critically ill patients is reviewed and options for sedation during endotracheal intubation in this population are discussed.

Analgo-sedation of patients with burns outside the operating room

Following the initial resuscitation of burn patients, the pain experienced may be divided into a 'background' pain and a 'breakthrough' pain associated with painful procedures. While background pain may be treated with intravenous opioids via continuous infusion or patient-controlled analgesia (PCA) and/or less potent oral opioids, breakthrough pain may be treated with a variety of interventions. The aim is to reduce patient anxiety, improve analgesia and ensure immobilization when required. Untreated pain and improper sedation may result in psychological distress such as post-traumatic stress disorder, major depression or delirium. This review summarizes recent developments and current techniques in sedation and analgesia in non-intubated adult burn patients during painful procedures performed outside the operating room (e.g. staple removal, wound-dressing, bathing). Current techniques of sedation and analgesia include different approaches, from a slight increase in background pain therapy (e.g. morphine PCA) to PCA with rapid-onset opioids, to multimodal drug combinations, nitrous oxide, regional blocks, or non-pharmacological approaches such as hypnosis and virtual reality. The most reliable way to administer drugs is intravenously. Fast-acting opioids can be combined with ketamine, propofol or benzodiazepines. Adjuvant drugs such as clonidine or NSAIDs and paracetamol (acetaminophen) have also been used. Patients receiving ketamine will usually maintain spontaneous breathing. This is an important feature in patients who are continuously turned during wound dressing procedures and where analgo-sedation is often performed by practitioners who are not specialists in anaesthesiology. Drugs are given in small boluses or by patient-controlled sedation, which is titrated to effect, according to sedation and pain scales. Patient-controlled infusion with propofol has also been used. However, we must bear in mind that burn patients often show an altered pharmacokinetic and pharmacodynamic response to drugs as a result of altered haemodynamics, protein binding and/or increased extracellular fluid volume, and possible changes in glomerular filtration. Because sedation and analgesia can range from minimal sedation (anxiolysis) to general anaesthesia, sedative and analgesic agents should always be administered by designated trained practitioners and not by the person performing the procedure. At least one individual who is capable of establishing a patent airway and positive pressure ventilation, as well as someone who can call for additional assistance, should always be present whenever analgo-sedation is administered. Oxygen should be routinely delivered during sedation. Blood pressure and continuous ECG monitoring should be carried out whenever possible, even if a patient is undergoing bathing or other procedures that may limit monitoring of vital pulse-oximetry parameters.

Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine

BACKGROUND

The Institute of Medicine calls for the use of clinical guidelines and practice parameters to promote "best practices" and to improve patient outcomes.

OBJECTIVE

2007 update of the 2002 American College of Critical Care Medicine Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock.

PARTICIPANTS

Society of Critical Care Medicine members with special interest in neonatal and pediatric septic shock were identified from general solicitation at the Society of Critical Care Medicine Educational and Scientific Symposia (2001-2006).

METHODS

The Pubmed/MEDLINE literature database (1966-2006) was searched using the keywords and phrases: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation (ECMO), and American College of Critical Care Medicine guidelines. Best practice centers that reported best outcomes were identified and their practices examined as models of care. Using a modified Delphi method, 30 experts graded new literature. Over 30 additional experts then reviewed the updated recommendations. The document was subsequently modified until there was greater than 90% expert consensus.

RESULTS

The 2002 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and AHA sanctioned recommendations. Centers that implemented the 2002 guidelines reported best practice outcomes (hospital mortality 1%-3% in previously healthy, and 7%-10% in chronically ill children). Early use of 2002 guidelines was associated with improved outcome in the community hospital emergency department (number needed to treat = 3.3) and tertiary pediatric intensive care setting (number needed to treat = 3.6); every hour that went by without guideline adherence was associated with a 1.4-fold increased mortality risk. The updated 2007 guidelines continue to recognize an increased likelihood that children with septic shock, compared with adults, require 1) proportionally larger quantities of fluid, 2) inotrope and vasodilator therapies, 3) hydrocortisone for absolute adrenal insufficiency, and 4) ECMO for refractory shock. The major new recommendation in the 2007 update is earlier use of inotrope support through peripheral access until central access is attained.

CONCLUSION

The 2007 update continues to emphasize early use of age-specific therapies to attain time-sensitive goals, specifically recommending 1) first hour fluid resuscitation and inotrope therapy directed to goals of threshold heart rates, normal blood pressure, and capillary refill 70% and cardiac index 3.3-6.0 L/min/m.

Ketamine-based total intravenous anesthesia versus isoflurane anesthesia in a swine model of hemorrhagic shock

BACKGROUND

Inhalational anesthetics can cause profound hemodynamic effects including decreases in systemic vascular resistance and cardiac inotropy. Although widely used in uncontrolled hemorrhagic shock (UHS), their consequences compared with other anesthetic regimens are not well-studied. Ketamine-based total intravenous anesthesia (TIVA) may produce less profound cardiovascular depression, and has been used during elective surgery but rarely during traumatic shock. The purpose of this study was to compare the effects of isoflurane (ISO) and TIVA regimens in a swine grade V liver injury model. We hypothesized that TIVA would result in less hypotension and dysfunctional inflammation than ISO.

METHODS

Twenty swine were randomized blindly to receive either 1% to 3% ISO, or intravenous ketamine, midazolam, and buprenorphine for maintenance anesthesia. Six animals acted as controls. After sedation and intubation, randomized anesthesia was initiated and monitored by an independent animal technician. Invasive lines were placed followed by celiotomy and splenectomy. Baseline mean arterial pressure (MAP) was documented and a grade V liver injury created. After 30 minutes of UHS, animals were resuscitated with 8 mL of Ringer's lactate per milliliter blood loss at 165 mL/min. MAP and tissue oxygen saturation (StO2) were continuously recorded. The animals were sacrificed 120 minutes after injury and lung tissue was harvested. Serum cytokines (interleukin-6 [IL-6], IL-8, and tumor necrosis factor-alpha [TNF-alpha]) were quantified with enzyme-linked immunosorbent assay. Lung cytokine mRNA levels were quantified with real time reverse transcriptase polymerase chain reaction.

RESULTS

Animal weight, liver injury pattern, and blood loss were similar (p > 0.1). The ISO group had a lower MAP at baseline (p = 0.02), at injury (p = 0.004), and study completion (p = 0.001). After resuscitation, MAP decreased in the ISO group but remained stable in the TIVA group. StO2 was significantly higher in the TIVA group immediately after injury (p = 0.004), but similar between groups throughout the remainder of the study. Animals who received TIVA trended toward higher levels of lactate and lower pH throughout the study, reaching significance at 30 minutes postinjury (p = 0.037 and 0.043). Inflammatory cytokine (IL-6, IL-8, and TNF-alpha) production did not differ between groups, however TNF-alpha mRNA production was significantly lower in the TIVA group (p = 0.04).

CONCLUSION

Although a TIVA regimen produced less pronounced hypotension in a swine model of UHS than did ISO, end-organ perfusion with TIVA appeared to be equivalent or inferior to ISO. In circumstances of limited resources, such as those experienced by forward Army surgical teams, a ketamine-based TIVA regimen may be an option for use in UHS.

Effects of nebulized ketamine on allergen-induced airway hyperresponsiveness and inflammation in actively sensitized Brown-Norway rats

Since airway hyperresponsiveness (AHR) and allergic inflammatory changes are regarded as the primary manifestations of asthma, the main goals of asthma treatment are to decrease inflammation and maximize bronchodilation. These goals can be achieved with aerosol therapy. Intravenous administration of the anesthetic, ketamine, has been shown to trigger bronchial smooth muscle relaxation. Furthermore, increasing evidence suggests that the anti-inflammatory properties of ketamine may protect against lung injury. However, ketamine inhalation might yield the same or better results at higher airway and lower ketamine plasma concentrations for the treatment of asthma. Here, we studied the effect of ketamine inhalation on bronchial hyperresponsiveness and airway inflammation in a Brown-Norway rat model of ovalbumin(OVA)-induced allergic asthma. Animals were actively sensitized by subcutaneous injection of OVA and challenged by repeated intermittent (thrice weekly) exposure to aerosolized OVA for two weeks. Before challenge, the sensitizened rats received inhalation of aerosol of phosphate-buffered saline (PBS) or aerosol of ketamine or injection of ketamine respectivity. Airway reactivity to acetylcholine (Ach) was measured in vivo, and various inflammatory markers, including Th2 cytokines in bronchoalveolar lavage fluid (BALF), as well as induciable nitric oxide synthase (iNOS) and nitric oxide (NO) in lungs were examined. Our results revealed that delivery of aerosolized ketamine using an ultrasonic nebulizer markedly suppressed allergen-mediated airway hyperreactivity, airway inflammation and airway inflammatory cell infiltration into the BALF, and significantly decreased the levels of interleukin-4 (IL-4) in the BALF and expression of iNOS and the concentration of NO in the inflamed airways from OVA-treated rats. These findings collectively indicate that nebulized ketamine attenuated many of the central components of inflammatory changes and AHR in OVA-provoked experimental asthma, potentially providing a new therapeutic approach against asthma.

Ketamine Improves Survival in Burn Injury Followed by Sepsis in Rats

Ketamine was reported to decrease cytokine production and improve survival after Escherichia coli-induced sepsis. We examined whether ketamine decreased interleukin (IL)-6 production and improved survival after 1) burn injury or 2) burn injury combined with sepsis (E. coli) at 24 h. Ketamine (10 mg/kg) or saline was given at 1 h after burn injury (G 1, 2, 5, 6), 24 h after burn injury (G 3, 4), or at E. coli inoculation (G 7, 8). Mortality was recorded for 7 days and IL-6 was measured in serum at 6 h after burn (G 1-2), 30 h after burn (G 3-4), or 6 h after sepsis (30 h after burn) (G 5-8). Burn injury only: Ketamine given immediately (1 h) after burn injury but not 24 h after, decreased the burn-induced increase of IL-6 but did not improve survival. Burn injury + sepsis: Ketamine given immediately after burn injury did not significantly decrease the sepsis-induced increase of IL-6 or improve survival. In contrast, ketamine given immediately after sepsis significantly improved survival (46.1% versus 13.3%, P = 0.008) and decreased IL-6 production (72,640 +/- 40,990 vs 332,300 +/- 32,300 pg/mL, P = 0.008). We conclude that ketamine therapy improves survival in burn injury followed by sepsis. This beneficial effect is probably achieved through interference with the inflammatory cascade, as evidenced by attenuation of the proinflammatory marker IL-6.

Reducing the global burden of sepsis in infants and children: a clinical practice research agenda

OBJECTIVE

Sepsis remains a predominant cause of mortality and morbidity in children in the developing and industrialized world. This review discusses a clinical practice research agenda to reduce this global burden.

DESIGN

Summary of the literature with analysis by experts.

RESULTS

Many interventions have been proven effective in decreasing sepsis. Heterologous immunization with attenuated Bacillus Camille Guerin vaccine reduces all-cause mortality, and specific immunizations further reduce morbidity and mortality from many specific microbes. Antepartum antibiotics reduce the prevalence of cerebral palsy and mortality in infants. Administration of antibiotics to neonates with signs of sepsis reduces all-cause mortality five-fold and can also reduce mortality in the big four killers of children: severe pneumonia, diarrhea, malaria, or measles. Immunonutrition with zinc and vitamin A can further reduce morbidity in diarrhea and pneumonia and reduce mortality in measles. First-hour rapid intravenous fluid resuscitation achieves 100% survival in dengue shock, and time-sensitive fluid resuscitation and inotropic support reduces mortality ten-fold in meningococcal septic shock. Multiple organ failure occurs when late or inadequate resuscitation results in systemic thrombosis or when infection is not eradicated because of immunosuppression or inadequate source control.

CONCLUSIONS

The global burden of sepsis can be reduced by 1) prevention with improved heterologous or specific vaccines and vitamin or mineral supplement programs; 2) early recognition and treatment with appropriate antibiotics, intravenous fluid resuscitation, and inotropic support in organized healthcare-delivery systems; and 3) development of new diagnostics and therapeutics that reduce systemic thrombosis, improve immune function, and kill resistant organisms.