Effects of different anaesthetic agents on immune cell function in vitro

The Impact of Different Anesthetics on the Distribution and Cytotoxic Function of NK Cell Subpopulations: An In Vitro Study

Only some subpopulations of natural killer (NK) cells have cytotoxic functionality, and the effects of anesthetics on these subpopulations are unknown. This study aimed to evaluate the in vitro effects of various anesthetics, both alone and in combination, on the distribution and cytotoxic function of NK cells and their subpopulations. Peripheral blood mononuclear cells (PBMCs) from eight healthy volunteers were treated for 4 h in vitro with dexmedetomidine, remifentanil, lidocaine, propofol, sevoflurane, and combinations in clinically relevant concentrations or left untreated. Flow cytometry was used to quantify the percentage of sampled NK cells and evaluate their distribution (CD56brightCD16neg, CD56brightCD16dim, CD56dimCD16neg, CD56dimCD16bright, and CD56negCD16bright) and cytotoxicity (Granzyme B (GrzB) and perforin) of NK cell subpopulations. Although the percentage of total NK cells did not change following exposure to anesthesia, the most important cytotoxic subpopulation (CD56dimCD16bright NK cells) decreased after exposure to both propofol (-3.58%, p = 0.045) and sevoflurane (-16.10%, p = 0.008) alone, and most combinations, especially in combination with lidocaine (propofol with lidocaine (-9.66%, p = 0.002) and sevoflurane with lidocaine (-21.90%, p < 0.001)). Dexmedetomidine and remifentanil had no effect on CD56dimCD16bright NK cells. Furthermore, no anesthetic regimen or combination altered the expression of GrzB and perforin in NK cells or NK cell subpopulations. In short, propofol and sevoflurane suppressed the highly cytotoxic phenotype (CD56dimCD16bright) of NK cells, with those exposed to sevoflurane combinations showing greater reductions. Immunosuppression was intensified with the inclusion of lidocaine in the anesthetic regimen.

Comparison between sevoflurane and propofol on immunomodulation in an in vitro model of sepsis

Introduction

Patients with sepsis often require sedation and/or anesthesia. Although the immunomodulatory effects of anesthetics have been increasingly recognized, the molecular mechanisms require better elucidation. We compared the effects of sevoflurane with propofol on the expression of pro- and anti-inflammatory biomarkers released by monocytes/macrophages and blood/bronchoalveolar lavage fluid (BALF) neutrophils, the phagocytic capacity of monocytes/ macrophages, and neutrophil migration, as well as mediators associated with alveolar epithelial and endothelial cells obtained from rats with sepsis.

Methods

Polymicrobial sepsis was induced by cecal ligation and puncture in nine male Wistar rats. After 48 h, animals were euthanized and their monocytes/alveolar macrophages, blood and BALF neutrophils, as well as alveolar epithelial and endothelial cells were extracted, and then exposed to (1) sevoflurane (1 minimal alveolar concentration), (2) propofol (50 μM), or (3) saline, control (CTRL) for 1 h.

Results

Sevoflurane reduced interleukin (IL)-6 mRNA expression in monocytes and alveolar macrophages (p = 0.007, p = 0.029), whereas propofol decreased IL-6 mRNA only in alveolar macrophages (p = 0.027) compared with CTRL. Sevoflurane increased IL-10 expression (p = 0.0002) in monocytes compared with propofol and increased IL-10 mRNA and transforming growth factor (TGF)-β mRNA (p = 0.037, p = 0.045) compared with CTRL. Both sevoflurane and propofol did not affect mRNA expression of IL-10 and TGF-β in alveolar macrophages. The phagocytic capacity of monocytes (p = 0.0006) and alveolar macrophages (p = 0.0004) was higher with sevoflurane compared with propofol. Sevoflurane, compared with CTRL, reduced IL-1β mRNA (p = 0.003, p = 0.009) and C-X-C chemokine receptor 2 mRNA (CXCR2, p = 0.032 and p = 0.042) in blood and BALF neutrophils, and increased CXCR4 mRNA only in BALF neutrophils (p = 0.004). Sevoflurane increased blood neutrophil migration (p = 0.015) compared with propofol. Both sevoflurane and propofol increased zonula occludens-1 mRNA (p = 0.046, p = 0.003) in alveolar epithelial cells and reduced Toll-like receptor 4 mRNA (p = 0.043, p = 0.006) in alveolar endothelial cells compared with CTRL. Only propofol reduced surfactant protein B mRNA (p = 0.028) in alveolar epithelial cells.

Discussion

Sevoflurane, compared with propofol, increased anti-inflammatory biomarkers in monocytes, but not in alveolar macrophages, enhanced monocyte/alveolar macrophage phagocytic capacity and increased neutrophil migration in in vitro experimental sepsis. Both propofol and sevoflurane protected lung epithelial and endothelial cells.

General Anesthesia in Early Childhood Significantly Reduces Asthma Incidence and Clinical Visits: A Nationwide Population-Based Cohort Study

Few studies have focused on the consequence of exposure to general anesthesia (GA) in children’s early life with the risk of asthma and disease outcomes. The present study examines the correlation between exposure to GA under three years old and the subsequent course of asthma in a nationwide population-based cohort study. Our cases were acquired from Taiwan’s National Health Insurance Research Database (NHIRD). Children under three years old with either GA exposure or not during in-patient treatment from 1997 to 2008 were included. The study group was age- and sex-matched with a ratio of 1:2 to create the control group for comparison. The cohort included 2261 cases with GA and 4522 cases without GA as a control group. The incidence of asthma onset was significantly reduced in patients with GA exposure under 3 three years old (hazard ratio 0.64 (95% confidence interval 0.57~0.72), p < 0.001). In addition, regardless of whether the asthmatic clinical visits were before or after GA exposure, asthma onset patients before GA exposure have significantly fewer clinical visits than those without GA exposure (both p < 0.001, respectively). Using the Kaplan–Meier method, we also demonstrated that GA exposure was associated with favorable clinical visits in patients with asthma, whether their asthma was onset before GA (p = 0.0102) or after GA exposure (p = 0.0418) compared to non-GA-exposed controls. In the present study, we demonstrated that children with early GA exposure under three years old were at a reduced risk of developing asthma compared to the general population. Furthermore, we first reported that GA exposure significantly reduced clinical visits in patients with asthma regardless of whether their asthma onset was before or after GA exposure. It is indicated that GA exposure at a younger age could have potential clinical benefits for asthma than non-GA-exposed controls.

Updated meta-analysis on intraoperative inspired fraction of oxygen and the risk of surgical site infection in adults undergoing general and regional anesthesia

This updated meta-analysis aims at exploring whether the use of systematic high vs low intraoperative oxygen fraction (FiO2) may decrease the incidence of postoperative surgical site infection during general (GA) or regional anesthesia (RA). PubMed, Cochrane CENTRAL, ClinicalTrials.gov databases were searched from January 1st, 1999 and July, 1st 2022, for randomized and quasi-randomized controlled trials that included patients in a high and low FiO2 groups and reported the incidence of SSI. The meta-analysis was conducted with a DerSimonian and Laird random-effects model. Thirty studies (24 for GA and 6 for RA) totaling 18,055 patients (15,871 for GA and 2184 for RA) were included. We have low-to-moderate-quality evidence that high FiO2 (mainly 80%) was not associated with a reduction of SSI incidence compared to low FiO2 (mainly 30%) in all patients (RR 0.90, 95%CI 0.79-1.03). Moderate inconsistency existed between studies (I2 = 38%). Subgroup analyses showed a moderate protective effect in patients undergoing GA (RR 0.86, 95%CI 0.75-0.99) (low level of evidence), while high FiO2 was not associated with a reduction of SSI in patients undergoing RA (RR 1.17, 95%CI 0.90-1.52) (moderate level of evidence). Sensitivity analyses restricted to patients ventilated without nitrous oxide (n = 20 studies), to patients operated from abdominal surgeries (n = 21 studies), and to patients suffering from deep SSI (n = 13 studies), all showed the absence of any significant effect of high FiO2. As a conclusion there is no compelling evidence that high FiO2 can improve postoperative patient's outcome on its own when good SSI prevention practices are properly applied. Recent well-designed and adequately powered randomized controlled trials add further weight to these results.

Effect of Inhalation Anesthetics on Tumor Metastasis

Many factors affect the prognosis of patients undergoing tumor surgery, and anesthesia is one of the potential influencing factors. In general anesthesia, inhalation anesthesia is widely used in the clinic because of its strong curative effect and high controllability. However, the effect of inhalation anesthetics on the tumor is still controversial. More and more research has proved that inhalation anesthetics can intervene in local recurrence and distant metastasis of tumor by acting on tumor biological behavior, immune response, and gene regulation. In this paper, we reviewed the research progress of diverse inhalation anesthetics promoting or inhibiting cancer in the critical events of tumor recurrence and metastasis, and compared the effects of inhalation anesthetics on patients' prognosis in clinical studies, to provide theoretical reference for anesthesia management of patients undergoing tumor surgery.

Anesthetic care influences long-term outcomes: What is the evidence?

Despite advances in cancer therapy surgery remains one of the most important treatments for solid tumors; however, even with the development of better and less invasive surgical techniques, surgery is characterized by the increased risk of tumor metastasis, accelerated growth of pre-existing micrometastasis and cancer recurrence. Total intravenous anesthesia (TIVA) and regional anesthesia have been proposed to improve long-term outcomes after cancer surgery by different mechanisms, including attenuation of the neuroendocrine response, immunosuppression, decreased opioid requirements (opioids promote angiogenesis and tumor growth) and avoidance of volatile inhalational agents. Much of the data that support these ideas originate from laboratory studies, while there is no clear consensus from the retrospective cohort studies to date. Several randomized controlled trials (RCTs) are in progress and may provide a better understanding regarding the role of the anesthesiologist in cancer surgery. The purpose of this review is to summarize the experimental and human data regarding the effect of anesthesia agents and anesthesia techniques on cancer outcomes.

Anesthetics or anesthetic techniques and cancer surgical outcomes: a possible link

As of 2018 cancer is responsible for almost 9.6 million deaths annually and, with an aging population, the incidence of cancer is expected to continue to rise. Surgery is an important treatment modality for patients with solid organ cancers. It has been postulated that, due to potentially overlapping processes underlying the development of malignancy and the therapeutic pathways of various anesthetic agents, the choice of anesthetic type and method of administration may affect post-operative outcomes in patients with cancer. This is a literature review of the most recent evidence extracted from various databases including PubMed, EMBASE, and the Cochrane, as well as journals and book reference lists. The review highlights the pathophysiological processes underpinning cancer development and the molecular actions of anesthetic agents, pre-clinical and retrospective studies investigating cancer and anesthetics, as well as ongoing clinical trials. Overall, there are conflicting results regarding the impact of regional vs. general anesthesia on cancer recurrence, whilst the majority of data suggest a benefit of the use of intravenous propofol over inhalational volatile anesthetics. The biological changes associated with the surgical inflammatory response offer a unique opportunity to intervene to counteract any potentially cancer-promoting effects.

Sedating Mechanically Ventilated COVID-19 Patients with Volatile Anesthetics: Insights on the Last-Minute Potential Weapons

Coronavirus Disease 2019 (COVID-19) has spread globally with the number of cases exceeding seventy million. Although trials on potential treatments of COVID-19 Acute Respiratory Distress Syndrome (ARDS) are promising, the introduction of an effective therapeutic intervention seems elusive. In this review, we explored the potential therapeutic role of volatile anesthetics during mechanical ventilation in the late stages of the disease. COVID-19 is thought to hit the human body via five major mechanisms: direct viral damage, immune overactivation, capillary thrombosis, loss of alveolar capillary membrane integrity, and decreased tissue oxygenation. The overproduction of pro-inflammatory cytokines will eventually lead to the accumulation of inflammatory cells in the lungs, which will lead to ARDS requiring mechanical ventilation. Respiratory failure resulting from ARDS is thought to be the most common cause of death in COVID-19. The literature suggests that these effects could be directly countered by using volatile anesthetics for sedation. These agents possess multiple properties that affect viral replication, immunity, and coagulation. They also have proven benefits at the molecular, cellular, and tissue levels. Based on the comprehensive understanding of the literature, short-term sedation with volatile anesthetics may be beneficial in severe stages of COVID-19 ARDS and trials to study their effects should be encouraged.

Effects of Desflurane and Sevoflurane anesthesia on regulatory T cells in patients undergoing living donor kidney transplantation: a randomized intervention trial

BACKGROUND

Volatile anesthetic agents used during surgery have immunomodulatory effects which could affect postoperative outcomes. Recognizing that regulatory T cells (Tregs) plays crucial roles in transplant tolerance and high peripheral blood Tregs associated with stable kidney graft function, knowing which volatile anesthetic agents can induce peripheral blood Tregs increment would have clinical implications. This study aimed to compare effects of desflurane and sevoflurane anesthesia on peripheral blood Tregs induction in patients undergoing living donor kidney transplantation.

METHODS

A prospective, randomized, double-blind trial in living donor kidney transplant recipients was conducted at a single center, tertiary-care, academic university hospital in Thailand during August 2015 - June 2017. Sixty-six patients were assessed for eligibility and 40 patients who fulfilled the study requirement were equally randomized and allocated to desflurane versus sevoflurane anesthesia during transplant surgery. The primary outcome included absolute changes of peripheral blood CD4⁺CD25⁺FoxP3⁺Tregs which measured by flow cytometry and expressed as the percentage of the total population of CD4⁺ T lymphocytes at pre-exposure (0-h) and post-exposure (2-h and 24-h) to anesthetic gas. P-value < 0.05 denoted statistical significance.

RESULTS

Demographic data were comparable between groups. No statistical difference of peripheral blood Tregs between desflurane and sevoflurane groups observed at the baseline pre-exposure (3.6 ± 0.4% vs. 3.1 ± 0.4%; p = 0.371) and 2-h post-exposure (3.0 ± 0.3% vs. 3.5 ± 0.4%; p = 0.319). At 24-h post-exposure, peripheral blood Tregs was significantly higher in desflurane group (5.8 ± 0.5% vs. 4.1 ± 0.3%; p = 0.008). Within group analysis showed patients receiving desflurane, but not sevoflurane, had 2.7% increase in peripheral blood Treg over 24-h period (p < 0.001).

CONCLUSION

This study provides the clinical trial-based evidence that desflurane induced peripheral blood Tregs increment after 24-h exposure, which could be beneficial in the context of kidney transplantation. Mechanisms of action and clinical advantages of desflurane anesthesia based on Treg immunomodulation should be investigated in the future.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02559297 . Registered 22 September 2015 - retrospectively registered.

General Anesthetics on Immune System Cytokines: A Narrative Review Article

Context

According to the previous studies, general anesthesia influences the immune system. Evaluating such impacts on the immune system helps to improve the management of anesthesia.

Evidence Acquisition

The current review aimed to summarize the literature related to the effects of general anesthesia agents on the cytokines. Google Scholar, PubMed, and ISI/Web of Sciences databases were searched using the following keywords: cytokine, general anesthesia, immune response, intravenous anesthetics, volatile anesthetics, opioids, benzodiazepines, and controlled ventilation.

Results

Long-term administration of general anesthesia drugs, due to their effects on cytokines, can lead to disease progression in patients with immune deficiency. Due to the conflicting results of various studies and the increasing number of patients with immune deficiency, the choice of the appropriate general anesthesia agents facilitates achieving the more favorable function of the cytokines.

Conclusions

It seems that the effect of general anesthesia on the immune system in healthy patients and short-term surgeries is not considerable and changes in the immune system are related to surgical trauma, particularly in major surgery.

A review of the effects of the anesthetic gas nitrous oxide on the immune system; a starting point for future experiences

Nitrous oxide is a common gas used as an anesthetic agent and analgesic medication in operating rooms. The gas inhibits vitamin B₁₂ dependent-methionine synthase, which converts L-homocysteine and 5-methyltetrahydrofolate to L-methionine and tetrahydrofolate, respectively, via a methylation process. The immune system has been frequently reported to be suppressed in anesthetized subjects during the postoperative period. Although previous reviews have focused on the pathophysiologic role of nitrous oxide, none of them has considered the harmful effects of nitrous oxide on the Defense system of the host. In this article, the authors review current studies on the effects of nitrous oxide on the immune system of both patients undergoing surgery and occupational exposure, as well as preclinical studies. Moreover, this paper opens a new horizon for future studies in the context of underlying mechanisms of nitrous oxide actions on the immune system.

Combined anesthesia shows better curative effect and less perioperative neuroendocrine disorder than general anesthesia in early stage NSCLC patients

Objectives

We aimed to compare the effects of general anesthesia with combined epidural and general anesthesia in patients with early-stage non-small cell lung carcinoma (NSCLC).

Methods

Patients scheduled to undergo tumor resection with adjuvant chemoradiotherapy were eligible. Patients in the control group received general anesthesia during surgery, and those in the observation group received combined epidural and general anesthesia. The hemodynamic factors mean arterial pressure (MAP), heart rate, end-tidal carbon dioxide, and oxygen saturation were measured. Serum levels of pro-inflammatory cytokines interleukin (IL)-1, IL-8, high-sensitivity C-reactive protein (hs-CRP), and tumor necrosis factor (TNF)-α as well as β-endorphin were measured by enzyme-linked immunosorbent assay. Serum malondialdehyde (MDA) was measured using the thiobarbituric acid method.

Results

The incidence of specific adverse events was reduced and overall and disease-free survival were improved in the observation group compared with the control group. MAP was generally lower in the observation group compared with the control group, as were the serum levels of IL-1, IL-8, hs-CRP, TNF-α, and MDA.

Conclusions

Compared with general anesthesia, combined epidural and general anesthesia may inhibit the occurrence of short-term adverse events and improve long-term outcomes by inhibiting inflammatory responses in patients with early-stage NSCLC after tumor resection.

Breakdown of blood brain barrier as a mechanism of post-traumatic epilepsy

Traumatic brain injury (TBI) accounts for approximately 16% of acute symptomatic seizures which usually occur in the first week after trauma. Children are at higher risk for post-traumatic seizures than adults. Post-traumatic seizures are a risk factor for delayed development of epilepsy. Delayed, chronic post-traumatic epilepsy is preceded by a silent period during which therapeutic interventions may arrest, revert or prevent epileptogenesis. A number of recent review articles summarize the most important features of post-traumatic seizures and epilepsy; this review will instead focus on the link between cerebrovascular permeability, epileptogenesis and ictal events after TBI. The possibility of acting on the blood-brain barrier (BBB) and the neurovascular unit to prevent, disrupt or treat post-traumatic epilepsy is also discussed. Finally, we describe the latest quest for biomarkers of epileptogenesis which may allow for a more targeted intervention.

Effects of anesthetic interventions on breast cancer behavior, cancer-related patient outcomes, and postoperative recovery

This narrative review will summarize our current understanding of the effects of perioperative interventions on patients undergoing surgical removal of breast malignancies. It will focus on how different anesthetic agents and perioperative interventions might affect both breast cancer behavior and/or tumor recurrence as well as postoperative recovery. The main objective of this study will be to describe the evidence and critically analyze preclinical and clinical studies on the use of intravenous versus inhaled anesthetic agents, opioids, regional anesthetics, and anesthetic adjuncts in patients undergoing breast cancer resection. We will look both at the evidence regarding cancer-related outcomes and postoperative recovery. A search of PubMed, from inception to May 2017 was performed using Mesh terms Breast Neoplasms [Mesh] OR cancer AND breast AND Anesthesia [Mesh]; "Anesthetics"[Mesh] AND "Breast Neoplasms/surgery"[Mesh]. Although no optimal anesthetic combination has been identified for patients undergoing breast cancer resection, it should be noted that based on the available evidence, an ideal anesthetic in this patient population would involve a combination of TIVA (propofol), regional anesthesia (paravertebral block)), non opioid sedatives (clonidine or dexmedetomidine), and COX-2 inhibition (ketorolac). Based on the current evidence, this combination of anesthetic and analgesic agents has the best chance of improving cancer-related outcomes and postoperative recovery.

The Effect of Anesthesia on the Immune System in Colorectal Cancer Patients

Colorectal cancer (CRC) is the key leading cause of high morbidity and mortality worldwide. Surgical excision is the most effective treatment for CRC. However, stress caused by surgery response can destroy the body's immunity and increase the likelihood of cancer dissemination and metastasis. Anesthesia is an effective way to control the stress response, and recent basic and clinical research has shown that anesthesia and related drugs can directly or indirectly affect the immune system of colorectal cancer patients during the perioperative period. Thus, these drugs may affect the prognosis of CRC surgery patients. This review is intended to summarize currently available data regarding the effects of anesthetics and related drugs on perioperative immune function and postoperative recurrence and metastasis in CRC patients. Determining the most suitable anesthesia for patients with CRC is of utmost importance.

The oxidative/anti-oxidative effects of sevoflurane on reproductive system of females: An experimental study

Objective:

A permanent balance exists between the production and elimination of reactive oxygen species in all living organisms. The aim of this study was to evaluate the effects of sevoflurane possibly causing an imbalance in the equation of reactive oxygen species on the female rat reproductive system.

Materials and Methods:

A total of 30 adult female Wistar-albino rats were placed into an anesthesia chamber to administer sevoflurane. Rats were randomly divided into six groups, each group consisting of five rats: the control group received 2 L/min O₂ 18 min/day for seven days; the first group received 1 minimum alveolar concentration (MAC) of sevoflurane and 2 L/min O₂ 18 min/day for seven days; the second group received 1 MAC of sevoflurane and 2 L/min O₂ 18 min/day for seven days with no treatment for the next seven days; the third group received 1 MAC of sevoflurane and 2 L/min O₂ 18 min/day for 14 days; the fourth group received 1 MAC of sevoflurane and 2 L/min O₂ 18 min/day for 14 days with no treatment for the next seven days; and the fifth group received 1 MAC of sevoflurane and 2 L/min O₂ 18 min/day for 14 days with no treatment for the next 14 days. Bilateral ovaries were subsequently removed for biochemical analysis of tissue anti-oxidative enzyme levels.

Results:

Slight fluctuations were detected in mean nitric oxide, prostaglandin E2, prostaglandin F2-alpha, superoxide dismutase, glutathione peroxidase, malondialdehyde, alginate dialdehyde, and xanthine oxidase levels between the groups; however, the differences were not significant (p>0.05).

Conclusion:

Sevoflurane has no effect on the activity of anti-oxidant systems in the rat ovary.

Immune Modulation by Volatile Anesthetics

Volatile general anesthetics continue to be an important part of clinical anesthesia worldwide. The impact of volatile anesthetics on the immune system has been investigated at both mechanistic and clinical levels, but previous studies have returned conflicting findings due to varied protocols, experimental environments, and subject species. While many of these studies have focused on the immunosuppressive effects of volatile anesthetics, compelling evidence also exists for immunoactivation. Depending on the clinical conditions, immunosuppression and activation due to volatile anesthetics can be either detrimental or beneficial. This review provides a balanced perspective on the anesthetic modulation of innate and adaptive immune responses as well as indirect effectors of immunity. Potential mechanisms of immunomodulation by volatile anesthetics are also discussed. A clearer understanding of these issues will pave the way for clinical guidelines that better account for the impact of volatile anesthetics on the immune system, with the ultimate goal of improving perioperative management.

Can anesthetic-analgesic technique during primary cancer surgery affect recurrence or metastasis?

PURPOSE

Mortality among cancer patients is more commonly due to the effects of metastasis and recurrence as opposed to the primary tumour. Various perioperative factors have been implicated in tumour growth, including anesthetic agents and analgesia techniques. In this narrative review, we integrate this information to present a summary of the best available evidence to guide the conduct of anesthesia for primary cancer surgery.

SOURCE

We conducted a search of the PubMed database up to May 31, 2015 to identify relevant literature using the search terms "anesthesia and metastases", "anesthetic drugs and cancer", "volatile anesthetic agents and cancer", and "anesthetic technique and cancer".

PRINCIPAL FINDINGS

There is conflicting evidence regarding volatile agents; however, the majority of studies are in vitro, suggesting that these agents are associated with enhanced expression of tumourigenic markers as well as both proliferation and migration of cancer cells. Nitrous oxide has not been shown to have any effect on cancer recurrence. Local anesthetic agents may reduce the incidence of cancer recurrence through systemic anti-inflammatory action in addition to direct effects on the proliferation and migration of cancer cells. Nonsteroidal anti-inflammatory drugs affect cancer cells via inhibition of cyclooxygenase 2 (COX-2), which leads to reduced resistance of the cancer cell to apoptosis and reduced production of prostaglandins by cancer cells. Nonsteroidal anti-inflammatory drugs also suppress the cancer cell growth cycle through effects independent of COX-2 inhibition. Opioids have been shown to inhibit the function of natural killer cells and to stimulate cancer cell proliferation through effects on angiogenesis and tumour cell signalling pathways. Supplemental oxygen at the time of surgery has a proangiogenic effect on micrometastases, while the use of perioperative dexamethasone does not affect overall rates of cancer survival.

CONCLUSIONS

Current laboratory research suggests that perioperative interventions may impact recurrence or metastasis through effects on cancer cell signalling, the immune response, or modulation of the neuroendocrine stress response. Further evidence is awaited from prospective randomized-controlled trials. Meanwhile, with limited data upon which to make strong recommendations, anesthesiologists should seek optimal anesthesia and analgesia for their patients based on individual risk-benefit analysis and best available evidence on outcomes other than cancer recurrence.

General anesthesia exposure in early life reduces the risk of allergic diseases: A nationwide population-based cohort study

General anesthesia (GA) has been used for second line treatment strategy for status asthmaticus in pediatric patients. The association between GA in children and risk of followed-up allergic diseases is unclear. This study aims to assess the risk of allergic diseases after GA in children.We did a nationwide retrospective cohort study by analyzing data from the National Health Insurance Research Database (NHIRD) in Taiwan. The subsequent risks for allergic diseases, including asthma (ICD-9: 493.X), allergic rhinitis (AR; ICD-9 CM code 477.X), and atopic dermatitis (AD; ICD-9-CM code 691.X), were compared between exposure to GA and none before 1 year of age throughout the follow-up period using the Cox proportional hazards model.Insurance claims data for 32,742 children younger than 1 year old from all insured children in the NHIRD. Of those, 2358 subjects were exposed to GA; 414 and 1944 children exposed to mask and intubation ventilation, respectively, served as the study cohort, whereas the remaining 30,384 children made up the comparison cohort. Children in the GA group were at a lower risk of developing asthma, AR and AD, with adjusted hazard ratios of 0.67 (0.62-0.72, 95%CI), 0.72 (0.68-0.77, 95%CI), 0.60 (0.56-0.64, 95%CI), respectively.Children who were exposed to GA in early life before 1 year of age had reduced risk of subsequently developing allergic diseases such as asthma, AD, and AR, when compared with general population.

Effects of propofol and isoflurane on haemodynamics and the inflammatory response in cardiopulmonary bypass surgery

Cardiopulmonary bypass (CPB) causes reperfusion injury that when most severe is clinically manifested as a systemic inflammatory response syndrome. The anaesthetic propofol may have anti-inflammatory properties that may reduce such a response. We hypothesised differing effects of propofol and isoflurane on inflammatory markers in patients having CBR Forty patients undergoing elective CPB were randomised to receive either propofol or isoflurane for maintenance of anaesthesia. CRP, IL-6, IL-8, HIF-1α (ELISA), CD11 and CD18 expression (flow cytometry), and haemoxygenase (HO-1) promoter polymorphisms (PCR/electrophoresis) were measured before anaesthetic induction, 4 hours post-CPB, and 24 hours later. There were no differences in the 4 hours changes in CRP, IL-6, IL-8 or CD18 between the two groups, but those in the propofol group had higher HIF-1α (P = 0.016) and lower CD11 expression (P = 0.026). After 24 hours, compared to the isoflurane group, the propofol group had significantly lower levels of CRP (P < 0.001), IL-6 (P < 0.001) and IL-8 (P < 0.001), with higher levels CD11 (P = 0.009) and CD18 (P = 0.002) expression. After 24 hours, patients on propofol had increased expression of shorter HO-1 GT(n) repeats than patients on isoflurane (P = 0.001). Use of propofol in CPB is associated with a less adverse inflammatory profile than is isofluorane, and an increased up-regulation of HO-1. This supports the hypothesis that propofol has anti-inflammatory activity.

Does pharmacotherapy influence the inflammatory responses during cardiopulmonary bypass in children?

Cardiopulmonary bypass (CPB) induces a systemic inflammatory response syndrome (SIRS) by factors such as contact of the blood with the foreign surface of the extracorporeal circuit, hypothermia, reduction of pulmonary blood flow during CPB and endotoxemia. SIRS is maintained in the postoperative phase, co-occurring with a counter anti-inflammatory response syndrome. Research on the effects of drugs administered before the surgery, especially in the induction phase of anesthesia, as well as drugs used during extracorporeal circulation, has revealed that they greatly influence these postoperative inflammatory responses. A better understanding of these processes may not only improve postoperative recovery but also enable tailor-made pharmacotherapy, with both health and economic benefits. In this review, we describe the pathophysiology of SIRS and counter anti-inflammatory response syndrome in the light of CPB in children and the influence of drugs used on these syndromes.

[Plasma levels of interleukin-10 and nitric oxide in response to two different desflurane anesthesia flow rates]

OBJECTIVE

This study investigated interleukin-10 and nitric oxide plasma levels following surgery to determine whether there is a correlation between these two variables and if different desflurane anesthesia flow rates influence nitric oxide and interleukin-10 concentrations in circulation.

MATERIALS AND METHODS

Forty patients between 18 and 70 years and ASA I-II physical status who were scheduled to undergo thyroidectomy were enrolled in the study.

INTERVENTIONS

Patients were allocated into two groups to receive two different desflurane anesthesia flow rates: high flow (Group HF) and low flow (Group LF).

MEASUREMENTS

Blood samples were drawn at the beginning (t0) and end (t1) of the operation and after 24h (t2). Plasma interleukin-10 and nitric oxide levels were measured using an enzyme-linked-immunosorbent assay and a Griess reagents kit, respectively. Hemodynamic and respiratory parameters were assessed.

RESULTS

There was no statistically significant difference between the two groups with regard to interleukin-10 levels at the times of measurement. Interleukin-10 levels were increased equally in both groups at times t1 and t2 compared with preoperative concentrations. For both groups, nitric oxide circulating concentrations were significantly reduced at times t1 and t2 compared with preoperative concentrations. However, the nitric oxide value was lower for Group HF compared to Group LF at t2. No correlation was found between the IL-10 and nitric oxide levels.

CONCLUSION

Clinical usage of two different flow anesthesia forms with desflurane may increase interleukin-10 levels both in Group HF and Group LF; nitric oxide levels circulating concentrations were significantly reduced at times t1 and t2 compared with preoperative concentrations; however, at 24h postoperatively they were higher in Group LF compared to Group HF. No correlation was detected between interleukin-10 and nitric oxide levels.

Comparison of effects of low-flow sevoflurane and desflurane anesthesia on neutrophil and T-cell populations

BACKGROUND

Numerous transient effects of anesthesia on postoperative immune status have been documented in the literature.

OBJECTIVE

This study was performed to test the hypothesis that the effects on neutrophil and T-cell populations differ with use of low-flow sevoflurane- and desflurane-induced anesthesia during abdominal surgery.

METHODS

Fifty adult patients (American Society of Anesthesiologists physical status I or II) aged 20 to 60 years were recruited for the study. Patients were randomly assigned to one of two study groups. Anesthesia was induced using fentanyl, propofol, and vecuronium. After intubation, patients in group 1 received sevoflurane, oxygen, and nitrous oxide at a flow rate of 6 L/min, and those in group 2 received desflurane, oxygen, and nitrous oxide at a flow rate of 6 L/min. Ten minutes after induction of anesthesia, the flow rate was decreased to 1 L/min in both groups. Total leukocyte, lymphocyte, and neutrophil counts, percentage of T helper lymphocytes (CD4), cytotoxic T lymphocytes (CD8), natural killer lymphocytes, and active T lymphocyte, CD4/CD8 ratio, and plasma cortisol values were assessed before and at 2 and 24 hours after induction of anesthesia.

RESULTS

In the desflurane group, at 2 hours after induction of anesthesia, a significant decrease was observed in the lymphocyte count, percentage of CD4 cells, and CD4/CD8 ratio, and a significant increase was noted in the neutrophil count and percentage of CD8 cells (P < 0.05). At 24 hours after induction of anesthesia, a significant increase was observed in the leukocyte and neutrophil counts, percentage of CD4 cells, and CD4/CD8 ratio (P < 0.05). There was no change in the other parameters studied. In the sevoflurane group, a significant decrease was observed in the lymphocyte count and percentage of natural killer cells. In addition, a significant increase was noted in the leukocyte and neutrophil counts at 24 hours after induction of anesthesia (P < 0.01). The increase in the neutrophil count in the desflurane group compared with that in the sevoflurane group was statistically significant (P < 0.05).

CONCLUSIONS

With use of the low-flow anesthesia technique, compared with desflurane, sevoflurane exerts minimal effects on neutrophil and T-cell populations, which supports our hypothesis.

Inflammatory pathways of seizure disorders

Epilepsy refers to a cluster of neurological diseases characterized by seizures. Although many forms of epilepsy have a well-defined immune etiology, in other forms of epilepsy an altered immune response is only suspected. In general, the hypothesis that inflammation contributes to seizures is supported by experimental results. Additionally, antiepileptic maneuvers may act as immunomodulators and anti-inflammatory therapies can treat seizures. Triggers of seizure include a bidirectional communication between the nervous system and organs of immunity. Thus, a crucial cellular interface protecting from immunological seizures is the blood-brain barrier (BBB). Here, we summarize recent advances in the understanding and treatment of epileptic seizures that derive from a non-neurocentric viewpoint and suggest key avenues for future research.

The perioperative use of nitrous oxide: renaissance of an old gas or funeral of an ancient relict?

PURPOSE OF REVIEW

Conflicting reports about adverse events following nitrous oxide (N(2)O) application have spurred a discussion whether N(2)O should be abandoned from clinical practice. Concurrently, N(2)O is increasingly used as a single anesthetic agent in medical procedures. This article reviews and discusses reports about the present use of N(2)O.

RECENT FINDINGS

Multiple publications demonstrate an increasing use of N(2)O as a procedural analgesic and sedative. Results from the Evaluation of Nitrous Oxide in the Gas Mixture for Anesthesia trial have been contrasted by recent studies reporting no increased risk for perioperative complications, particularly related to the cardiovascular and cerebrovascular system. Recent studies show that electroencephalogram-based anesthesia depth monitoring is not compatible with the use of N(2)O because of its distinct influence on electroencephalogram wave patterns. The clinical relevance of the proposed neurotoxicity, immunosuppression and influence on methionine metabolism remains unclear. Recently, its acute and long-term analgesic potency has been proven. Occupational exposure might pose a relevant health hazard.

SUMMARY

Based on the present literature, abolishment of N(2)O is controversial. When avoided in patients at risk for adverse events, N(2)O is still a valuable supplement to general anesthesia and a potent procedural analgesic drug. In the latter, its use by nonanesthesiologists should be discouraged.

Plasma levels of interleukin-10 and nitric oxide in response to two different desflurane anesthesia flow rates

OBJECTIVE

This study investigated interleukin-10 and nitric oxide plasma levels following surgery to determine whether there is a correlation between these two variables and if different desflurane anesthesia flow rates influence nitric oxide and interleukin-10 concentrations in circulation.

MATERIALS AND METHODS

Forty patients between 18 and 70 years and ASA I-II physical status who were scheduled to undergo thyroidectomy were enrolled in the study.

INTERVENTIONS

Patients were allocated into two groups to receive two different desflurane anesthesia flow rates: high flow (Group HF) and low flow (Group LF).

MEASUREMENTS

Blood samples were drawn at the beginning (t0) and end (t1) of the operation and after 24h (t2). Plasma interleukin-10 and nitric oxide levels were measured using an enzyme-linked-immunosorbent assay and a Griess reagents kit, respectively. Hemodynamic and respiratory parameters were assessed.

RESULTS

There was no statistically significant difference between the two groups with regard to interleukin-10 levels at the times of measurement. Interleukin-10 levels were increased equally in both groups at times t1 and t2 compared with preoperative concentrations. For both groups, nitric oxide circulating concentrations were significantly reduced at times t1 and t2 compared with preoperative concentrations. However, the nitric oxide value was lower for Group HF compared to Group LF at t2. No correlation was found between the IL-10 and nitric oxide levels.

CONCLUSION

Clinical usage of two different flow anesthesia forms with desflurane may increase interleukin-10 levels both in Group HF and Group LF; nitric oxide levels circulating concentrations were significantly reduced at times t1 and t2 compared with preoperative concentrations; however, at 24h postoperatively they were higher in Group LF compared to Group HF. No correlation was detected between interleukin-10 and nitric oxide levels.

Cytokine profile in patients undergoing minimally invasive surgery with balanced anesthesia

Patients undergoing surgical procedure develop an inflammatory response due to surgical trauma that may be modulated by anesthetics. The aim of this study was to investigate the cytokine profile in the plasma of adult patients who underwent minimally invasive surgery with balanced anesthesia with propofol, fentanyl, and sevoflurane. The study included 15 healthy patients scheduled for tympanoplasty or septoplasty under balanced anesthesia. Blood samples were drawn at four time points: before anesthesia, before surgery, 120 min after anesthesia induction, and on the first postoperative day. Plasma interleukin (IL)-1β, -2, -4, -6, -8, -10, -12, TNF-α, and INF-γ levels were assessed by flow cytometry. IL-6 levels were elevated on the day after the surgery (p < 0.001). All other cytokines did not change either during or after balanced anesthesia (p > 0.05). In conclusion, balanced anesthesia with propofol, fentanyl, and sevoflurane anesthesia is not associated with intraoperative changes in the plasma cytokines in healthy patients undergoing minimally invasive otorhinological surgeries. Considering IL-6 results, a postoperative inflammatory response may have occurred due to surgical stress.

Leukocyte DNA Damage and Wound Infection after Nitrous Oxide Administration

Background:

Nitrous oxide inactivates methionine synthase and may lead to DNA damage and wound infection. By using single-cell gel electrophoresis (comet assay), the authors determined the effect of nitrous oxide on DNA damage in circulating leukocytes.

Methods:

In this double-blind, randomized controlled trial, 91 patients undergoing major colorectal surgery were randomized to receive 70% nitrous oxide (n = 31) or nitrous oxide-free anesthesia using 30 (n = 30) or 80% (n = 30) oxygen. Venous blood was collected before and 24 h after surgery. The primary outcome was extent of DNA damage, quantified as the percentage of DNA staining intensity in the comet tail using digital fluorescence microscopy. Incidence of postoperative wound infection was also recorded.

Results:

Nitrous oxide exposure was associated with a two-fold increase in the percentage of DNA intensity in tail (P = 0.0003), but not in the 30 (P = 0.181) or 80% oxygen groups (P = 0.419). There was a positive correlation between the duration of nitrous oxide exposure and extent of DNA damage, r = 0.33, P = 0.029. However, no correlation was observed in nitrous oxide-free patients. The proportions of postoperative wound infection, using the Centers for Disease Control and Prevention criteria, were 19.4% (6 of 31) in the 70% nitrous oxide group and 6.7% (2 of 30) in both the 30 and 80% oxygen groups, P = 0.21. An increase in DNA damage was associated with a higher risk of wound infection, adjusted odds ratio (95% CIs): 1.19 (1.07–1.34), P = 0.003.

Conclusions:

Nitrous oxide increased DNA damage compared with nitrous oxide-free anesthesia and was associated with postoperative wound infection.

Comparative effects of flurbiprofen and fentanyl on natural killer cell cytotoxicity, lymphocyte subsets and cytokine concentrations in post-surgical intensive care unit patients: prospective, randomized study

PURPOSE

The purpose of this study was to compare the effect of the long-term administration of flurbiprofen and fentanyl in the intensive care unit on natural killer cell cytotoxicity (NKCC), lymphocyte subsets and cytokine levels.

METHODS

In this prospective study, patients scheduled for at least 48 h sedation after neck surgery were randomly assigned to two groups called group N and group F. Group N patients were sedated with propofol and flurbiprofen after surgery (n = 12), while group F patients were sedated with propofol and fentanyl (n = 13). The NKCC, lymphocyte subsets, and plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-10 were measured before and at the end of surgery, on postoperative day (POD) 1 and POD2.

RESULTS

The NKCC was significantly higher on POD1 in group N than in group F (14.5 ± 11.2 versus 6.3 ± 4.1%, p < 0.05), the difference between the groups disappearing on POD2. Lymphocyte subsets and plasma levels of cytokines were not significantly different between the two groups during the study period.

CONCLUSIONS

Transient suppressive effects on NKCC were observed in the fentanyl group as compared to the flurbiprofen group. This suggests that when choosing postoperative analgesics, physicians should bear in mind the potential immunosuppressive effects of these agents in patients requiring prolonged sedation in the intensive care unit.

Applications of nitrous oxide for procedural sedation in the pediatric population

OBJECTIVE

The objective of this review was to provide a general descriptive account of the physical properties, end-organ effects, therapeutic applications, and delivery techniques of nitrous oxide (N2O) as used in the arena of procedural sedation.

DATA SOURCE

A computerized bibliographic search regarding the applications of nitrous for provision of sedation and analgesia during procedures with an emphasis on the pediatric population was performed.

RESULTS

The end-organ effects of N2O have been well described in the operating room setting. Aside from its effects on the central nervous system of sedation and analgesia, N2O may alter intracerebral dynamics and alter cerebral blood flow and intracranial pressure especially in patients with altered intracranial compliance. Effects on ventilation include a dose-related depression of ventilatory function and control of upper airway patency. These effects are generally limited in the absence of comorbid diseases and potentiated by other sedative and analgesic agents. The more clinically significant respiratory effect of N2O on ventilatory function is a dose-dependent depression of the ventilatory response to hypoxemia. Hemodynamic effects include a mild direct depressant effect on myocardial function, which in the absence of comorbid cardiac disease is generally compensated by stimulation of the sympathetic nervous system. Nitrous oxide may potentially aggravate pulmonary hypertension. Additional physiologic effects on neurologic and hematologic function may result in inactivation of the enzyme, methionine synthetase. Recent concern has also been raised regarding the potential effects of N2O on immune function and its relationship to perioperative surgical site infections. Given differences in the solubility, N2O will diffuse into and significantly expand gas-filled cavities. Chronic exposure of health care works to N2O is also a concern. Although there are limited data in the literature to clearly substantiate concerns regarding the reproductive toxicity of occupational exposure to N2O, appropriate scavenging and use of other techniques are mandatory. Nitrous oxide has been shown to be effective for a variety of minor surgical procedures such as venipuncture, intravenous cannula placement, lumbar puncture, bone marrow aspiration, laceration repair, dental care, and minor dermatologic procedures. It is generally as effective as midazolam, with several studies demonstrating it to be more effective. However, its utility is not as great in severely painful procedures such as fracture reduction. Demonstrated advantages to parenteral sedation include a more rapid onset and a shorter recovery time with the majority of patients preferring it to over other agents or agreeing to its use for subsequent procedures. The literature also suggests increased success rates with simple procedures such as intravenous cannula placement when compared with placebo. In general, life-threatening adverse events have not been reported. Most common adverse effects include dysphoria and vomiting. For more painful procedures, combination with another agent may be used, and in all cases, topical or infiltrative local anesthesia is recommended.

CONCLUSIONS

In general, N2O is a useful adjunct for procedural sedation. Given the variety of procedures performed in the pediatric patient, ongoing research is required to identify the most appropriate and effective use of this agent. This may be particularly relevant when evaluating its use for procedures associated with significant pain. In these scenarios, the combination of N2O with other agents needs to be evaluated. Given the potential for adverse effects, strict adherence to published guidelines regarding procedural sedation and monitoring is suggested.

Thoracic epidural analgesia inhibits the neuro-hormonal but not the acute inflammatory stress response after radical retropubic prostatectomy

BACKGROUND

Epidural anaesthesia and analgesia has been shown to suppress the neuro-hormonal stress response, but its role in the inflammatory response is unclear. The primary aim was to assess whether the choice of analgesic technique influences these processes in patients undergoing radical retropubic prostatectomy.

METHODS

Twenty-six patients were randomized to Group P (systemic opioid-based analgesia) or Group E (thoracic epidural-based analgesia) perioperatively. Induction and maintenance of anaesthesia followed a standardized protocol. The following measurements were made perioperatively: plasma cortisol, glucose, insulin, C-reactive proteins, leucocyte count, plasma cytokines [interleukin (IL)-6, tumour necrosis factor (TNF)-α], and pokeweed mitogen-stimulated cytokines [interferon (IFN)-γ, IL-2, IL-12p70, IL-10, IL-4, and IL-17]. Other parameters recorded were pain, morphine consumption, and perioperative complications.

RESULTS

Plasma concentration of cortisol and glucose were significantly higher in Group P compared with Group E at the end of surgery, the mean difference was 232 nmol litre(-1) [95% confidence interval (CI) 84-381] (P=0.004) and 1.6 mmol litre(-1) (95% CI 0.6-2.5) (P=0.003), respectively. No significant differences were seen in IL-6 and TNF-α at 24 h (P=0.953 and 0.368, respectively) and at 72 h (P=0.931 and 0.691, respectively). IL-17 was higher in Group P compared with Group E, both at 24 h (P=0.001) and 72 h (P=0.018) after operation. Pain intensity was significantly greater in Group P compared with Group E (P<0.05) up to 24 h.

CONCLUSIONS

In this small prospective randomized study, thoracic epidural analgesia reduced the early postoperative stress response but not the acute inflammatory response after radical retrobupic prostatectomy, suggesting that other pathways are involved during the acute phase reaction.

Sevoflurane reduces clinical disease in a mouse model of multiple sclerosis

Background

Inhalational anesthetics have been shown to influence T cell functions both in vitro and in vivo, in many cases inducing T cell death, suggesting that exposure to these drugs could modify the course of an autoimmune disease. We tested the hypothesis that in mice immunized to develop experimental autoimmune encephalomyelitis (EAE), a well established model of multiple sclerosis (MS), treatment with the commonly used inhalational anesthetic sevoflurane would attenuate disease symptoms.

Methods

C57Bl6 female mice were immunized with myelin oligodendrocyte glycoprotein (MOG) peptide residues 35 to 55 to induce a chronic demyelinating disease. At day 10 after immunization, the mice were subjected to 2 h of 2.5% sevoflurane in 100% oxygen, or 100% oxygen, alone. Following treatment, clinical scores were monitored up to 4 weeks, after which brain histology was performed to measure the effects on astrocyte activation and lymphocyte infiltration. Effects of sevoflurane on T cell activation were studied using splenic T cells isolated from MOG peptide-immunized mice, restimulated ex vivo with MOG peptide or with antibodies to CD3 and CD28, and in the presence of different concentrations of sevoflurane. T cell responses were assessed 1 day later by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for proliferation, lactate dehydrogenase (LDH) release for cell death, and inflammatory activation by production of interleukin (IL)-17 and interferon (IFN)γ.

Results

Clinical scores in the oxygen-treated group increased until day 28 at which time they showed moderate to severe disease (average clinical score of 2.9). In contrast, disease progression in the sevoflurane-treated group increased to 2.1 at day 25, after which it remained unchanged until the end of the study. Immunohistochemical analysis revealed reduced numbers of infiltrating leukocytes and CD4⁺ cells in the CNS of the sevoflurane-treated mice, as well as reduced glial cell activation. In splenic T cells, low doses of sevoflurane reduced IFNγ production, cell proliferation, and increased LDH release.

Conclusions

These results are the first to show attenuation of EAE disease by an inhaled anesthetic and are consistent with previous reports that inhaled anesthetics, including sevoflurane, can suppress T cell activation that, in the context of autoimmune diseases such as MS, could lead to reduced clinical progression.

The association between nitrous oxide and postoperative mortality and morbidity after noncardiac surgery

BACKGROUND

Nitrous oxide (N2O) has been widely used in clinical anesthesia for >150 years. However, use of N2O has decreased in recent years because of concern about the drug's metabolic side effects. But evidence that routine use of N2O causes clinically important toxicity remains elusive. We therefore evaluated the relationship between intraoperative N2O administration and 30-day mortality as well as a set of major inpatient postoperative complications (including mortality) in adults who had general anesthesia for noncardiac surgery.

METHODS

We evaluated 49,016 patients who had noncardiac surgery at the Cleveland Clinic between 2005 and 2009. Among 37,609 qualifying patients, 16,961 were given N2O ("nitrous," 45%) and 20,648 were not ("nonnitrous," 55%). Ten thousand seven hundred fifty-five nitrous patients (63% of the total) were propensity score-matched with 10,755 nonnitrous patients. Matched nitrous and nonnitrous patients were compared on 30-day mortality and a set of 8 in-hospital morbidity/mortality outcomes.

RESULTS

Inhalation of N2O intraoperatively was associated with decreased odds of 30-day mortality (odds ratio [OR]: 97.5% confidence interval, 0.67, 0.46-0.97; P = 0.02). Furthermore, nitrous patients had an estimated 17% (OR: 0.83, 0.74-0.92) decreased odds of experiencing major in-hospital morbidity/mortality than nonnitrous (P < 0.001). Among the individual morbidities, intraoperative N2O use was only associated with significantly lower odds of having pulmonary/respiratory morbidities (OR, 95% Bonferroni-adjusted CI: 0.59, 0.44-0.78).

CONCLUSIONS

Intraoperative N2O administration was associated with decreased odds of 30-day mortality and decreased odds of in-hospital mortality/morbidity. Aside from its specific and well-known contraindications, the results of this study do not support eliminating N2O from anesthetic practice.

Xenon anesthesia reduces TNFα and IL10 in bariatric patients

BACKGROUND

Anesthesia is able to modulate the balance between proinflammatory and anti-inflammatory cytokine production during surgery. The aim of this study is to assess the effect of three anesthesia approaches, total intravenous anesthesia (TIVA), inhalation anesthesia, and xenon anesthesia, on sieric levels of nitric oxide (NO), IL6, IL10, and TNFα in obese patients undergoing Roux-en-Y laparoscopic gastric bypass.

METHODS

Thirty adult morbidly obese patients (BMI > 35) scheduled for Roux-en-Y laparoscopic gastric bypass were randomly recruited and allocated to TIVA (N = 10), inhalation anesthesia (SEV, N = 10), and xenon anesthesia (XE, N = 10). Exclusion criteria were ASA IV, age <18 or >60 years, and Mallampati IV. Opioid dosage and ventilation parameters were standardized. Sieric levels of NO, IL6, IL10, and TNFα were assessed at T0 (before induction of anesthesia), T1 (end of surgery), and T2 (12 h after the end of surgery). We compared the relative cytokine level variations (delta) at T1 and T2 and the cytokine exposure levels calculated as the area under the curve (AUC) between T0 and T2 in the XE and non-XE (SEV + TIVA) groups.

RESULTS

At T1, we found a significant ΔIL10 (reduction) and ΔTNFα (reduction) between XE and SEV (p < 0.05) and XE and TIVA (p < 0.05) groups. At T2, ΔIL10 was still significant. Furthermore, we found a reduced AUC value for TNFα in the XE group.

CONCLUSIONS

Xenon anesthesia seems able to inhibit postoperative proinflammatory cytokine imbalance in morbidly obese patients undergoing Roux-en-Y laparoscopic gastric bypass; the reduced ΔTNFα at T1 and the reduced global exposition to TNFα in the XE group may explain the reduced ΔIL10 at T1 and T2.

FOXP3+ CD4+ Tregs lose suppressive potential but remain anergic during transient inflammation in human

Tregs are crucial in controlling inflammation. Although the transcription factor FOXP3 is the most applicable phenotype marker of Tregs, it does not indisputably characterize suppressive function during T-cell activation in vitro. A question that remains is: what is the functionality of FOXP3(+) T cells during inflammation in vivo? We studied FOXP3(+) T cells in a human model of acute inflammation due to cardiac surgery. Twenty-five children who underwent cardiac surgery for correction of a septum defect were included. Following surgery, we observed a transient systemic inflammatory response accompanied by an increased proportion of CD25(bright) T cells with sustained Treg phenotype. During this transient immune activation, both the percentage of CD4(+) FOXP3(+) cells and the level of expression of FOXP3 in the CD4(+) CD25(bright) CD127(low) population increased. While Tregs remained present during systemic inflammation and continued to be anergic, the capacity to suppress effector T cells was reduced. The reduced suppressive state of Tregs could be induced in vitro by plasma obtained during the peak of inflammation after surgery. These data show that inflammation inhibits Treg function through soluble factors present in plasma. These results underscore the functional role of FOXP3(+) Tregs during inflammation in vivo.

Genotoxicity, cytotoxicity and gene expression in patients undergoing elective surgery under isoflurane anaesthesia

There are numerous studies reporting on the effects of inhalation anaesthesia in cells of exposed individuals but not much is known about the ability of isoflurane (ISF) to induce oxidative DNA damage. However, surgery is often associated with a temporary perioperative immunological alteration, and some volatile anaesthetics seem to contribute to a transient lymphocytopenia after surgery. We conducted a study to evaluate a possible genotoxic effect, including oxidative DNA damage, and apoptosis in peripheral lymphocytes of 20 patients American Society of Anaesthesiologists physical status I undergoing minor elective surgery lasting at least 120 min, under anaesthesia with ISF. We also investigated the expression of several genes in blood cells. Blood samples were collected at three time points: before anaesthesia (T(1)), 2 h after the beginning of anaesthesia (T(2)) and on the first post-operative day (T(3)). General DNA damage and oxidised bases (Fpg and endo III-sites) in blood lymphocytes were evaluated using the comet assay. Lymphocytes were phenotyped and apoptosis was evaluated by flow cytometry. In addition, expressions of hOGG1 and XRCC1, genes involved in DNA repair, and BCL2, a gene related to apoptosis, were assessed by quantitative real-time polymerase chain reaction. Results showed no statistically significant difference in the level of DNA damage and oxidised bases among the three sampling times. Anaesthesia with ISF did not increase the percentage of cells in early or late apoptosis in cytotoxic or helper T lymphocytes. Lower hOGG1 and BCL2 expressions were detected at T(3) in comparison to the other two previous time points, and there was significantly lower expression of XRCC1 at T(3) in relation to T(2). In conclusion, the exposure to ISF did not result in genotoxicity and cytotoxicity in lymphocytes and in toxicogenomic effect in leukocytes, although DNA repair and apoptosis-related genes were down-regulated on the first post-operative day.

Effect of anaesthesia maintained with sevoflurane and propofol on surgical site infection after elective open gastrointestinal surgery

Perioperative increase in oxidative activity in surgical patients reportedly prevents postoperative surgical site infection (SSI). Several clinical studies have shown that oxidative activity under sevoflurane anaesthesia was higher than that under propofol anaesthesia. Therefore, we hypothesised that sevoflurane anaesthesia would discourage SSI compared with propofol anaesthesia. To examine the effect of anaesthesia maintained with sevoflurane and propofol on SSI, a total of 265 consecutive adult patients, with American Society of Anesthesiologists physical status 1-3, who underwent elective open gastrointestinal surgery under general anaesthesia, were surveyed for SSI between January 2007 and December 2008. Sevoflurane or propofol was selected to maintain anaesthesia in 95 and 170 patients, respectively. A propensity score was used for pairwise matching of these patients to avoid selection biases between the two methods of anaesthesia. Propensity matching yielded 84 pairs of patients. We compared standardised infection ratios (SIRs), i.e. the quotient of the number of SSI cases observed and the number of SSI cases expected, calculated using data from the National Nosocomial Infection Surveillance, between sevoflurane and propofol anaesthesia. After propensity matching, SIR after sevoflurane anaesthesia was 1.89 [95% confidence interval (CI): 1.46-2.32], which was significantly lower than after propofol anaesthesia (4.78; 95% CI: 4.30-5.27) (P=0.02). This study suggests that sevoflurane tends to suppress SSI after elective open gastrointestinal surgery compared with propofol.