Modulation of oxygen-free radicals from human leukocytes during halothane- and enflurane- induced general anesthesia

Effect of sevoflurane on the inflammatory response during cardiopulmonary bypass in cardiac surgery: the study protocol for a randomized controlled trial

Background

Recent experimental evidence shows that sevoflurane can reduce the inflammatory response during cardiac surgery with cardiopulmonary bypass. However, this observation so far has not been assessed in an adequately powered randomized controlled trial.

Methods

We plan to include one hundred patients undergoing elective coronary artery bypass graft with cardiopulmonary bypass who will be randomized to receive either volatile anesthetics during cardiopulmonary bypass or total intravenous anesthesia. The primary endpoint of the study is to assess the inflammatory response during cardiopulmonary bypass by measuring PMN-elastase serum levels. Secondary endpoints include serum levels of other pro-inflammatory markers (IL-1β, IL-6, IL-8, TNFα), anti-inflammatory cytokines (TGFβ and IL-10), and microRNA expression in peripheral blood to achieve possible epigenetic mechanisms in this process. In addition clinical endpoints such as presence of major complications in the postoperative period and length of hospital and intensive care unit stay will be assessed.

Discussion

The trial may determine whether adding volatile anesthetic during cardiopulmonary bypass will attenuate the inflammatory response.

Trial registration

ClinicalTrials.gov NCT02672345. Registered on February 2016 and updated on June 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-020-04809-x.

Sevoflurane prevents liver inflammatory response induced by lung ischemia-reperfusion

BACKGROUND

Transplants cause ischemia-reperfusion (IR) injury that can affect distant organs. Liver is particularly sensitive to IR injury. The present randomized experimental study was designed to investigate a possible protective effect of sevoflurane against liver inflammatory response to lung IR in a lung upper lobe left autotransplant model.

METHODS

Two groups (sevoflurane and control) of eight swines each were submitted to upper lobe left lung autotransplant. Hypnotic maintenance was performed with sevoflurane 3% or propofol 8 to 10 mg/kg per hr until pneumonectomy was done; then propofol was used for all animals. Blood and liver samples were taken in four different moments: prepneumonectomy, prereperfusion, 10 min postreperfusion and 30 min postreperfusion to measure levels of interleukin (IL)-1β, IL-10, tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1, nuclear factor (NF)-κB, C-reactive protein, ferritin and caspase 3. Non-parametric test was used to find statistical meaning.

RESULTS

Lung IR markedly increased the expression of TNF-α, IL-1β, MCP-1, NF-κB and caspase activity in control livers compared with basal levels, whereas liver IL-10 expression decreased 10 and 30 min post-reperfusion. Sevoflurane significantly decreased TNF-α, IL-1β, MCP-1, NF-κB liver expression and caspase 3 activity. Sevoflurane also reverted the lung IR-induced decrease in IL-10 expression.

CONCLUSIONS

The present results indicate that lung IR caused hepatic injury. Sevoflurane attenuated liver injury in a model of upper lobe left lung autotransplant in pigs.

Effects of desflurane, sevoflurane and propofol on phagocytosis and respiratory burst activity of human polymorphonuclear leucocytes in bronchoalveolar lavage

BACKGROUND AND OBJECTIVE

In polymorphonuclear leucocytes, phagocytosis and respiratory burst activity are mainly responsible for bacterial killing. We aimed to investigate the effects of anaesthesia with desflurane, sevoflurane and propofol on these functional activities of polymorphonuclear leucocytes in bronchoalveolar lavage fluid.

METHODS

Sixty patients scheduled to have tympanoplasty surgery were studied. The patients were divided into three groups (group D, desflurane; group S, sevoflurane; group P, propofol). Anaesthesia was induced with propofol, fentanyl and rocuronium in all groups. Anaesthesia was maintained with inhalation agent or propofol. Bronchoalveolar lavage was performed immediately after induction of anaesthesia and after surgical procedure by a fibreoptic bronchoscope. Leucocyte respiratory burst and phagocytic activity in bronchoalveolar lavage fluid were determined by flow cytometric analysis of gated leucocyte populations within 2 h after each bronchoalveolar lavage sample. Changes in leucocyte functions with time were expressed as mean fluorescence intensity.

RESULTS

There were no significant differences in phagocytic activity of polymorphonuclear leucocytes within and between the groups. The respiratory burst function of polymorphonuclear leucocytes showed a significant increase after surgery in group P (P < 0.05). When we compared the differences between the three groups, we found the difference in mean fluorescence intensity as statistically significant between group P and group S.

CONCLUSION

This study showed that propofol anaesthesia increased the respiratory burst function of polymorphonuclear leucocytes in bronchoalveolar lavage fluid.

Effects of Sevoflurane on Cytokine Balance in Patients Undergoing Coronary Artery Bypass Graft Surgery

OBJECTIVE

The effects of sevoflurane on proinflammatory cytokines related to ischemic-reperfusion injury are not clear. The hypothesis was tested that sevoflurane decreases myocardial ischemic-reperfusion injury by suppressing proinflammatory cytokines.

DESIGN

Prospective, randomized study.

SETTING

A medical university heart center.

PARTICIPANTS

Twenty-three patients undergoing coronary artery bypass surgery allocated randomly into 2 groups.

INTERVENTIONS

Anesthesia for 23 patients undergoing coronary artery bypass surgery was maintained using either fentanyl (30 microg/kg) with propofol (2-8 mg/kg/h) in the control group (n = 10) or fentanyl (30 microg/kg) with 0.5% to 1.0% sevoflurane in the sevoflurane group (n = 13).

MEASUREMENTS AND MAIN RESULTS

Interleukin (IL)-6, IL-8, IL-10, and IL-1 receptor antagonist (IL-1ra) were measured by enzyme-linked immunosorbent assay. Troponin-T and creatine kinase-MB isoenzyme (CK-MB) were measured by enzyme immunoassay and ultraviolet absorption spectrophotometry, respectively. Serum IL-6 and IL-8 concentrations in both groups increased significantly over baseline from 60 minutes after declamping the aorta (p < 0.001). The increases were greater in the control group than in the sevoflurane group (p < 0.05). Serum IL-10 and IL-1ra concentrations in both groups increased significantly over baseline from 60 minutes after declamping the aorta (p < 0.001). There were no differences between the two groups. Serum troponin-T and CK-MB concentrations increased significantly in both groups from 60 minutes after declamping the aorta (p < 0.001); the increases were greater in the control group (p < 0.05).

CONCLUSION

Sevoflurane suppressed the production of IL-6 and IL-8, but not IL-10 and IL-1ra. Changes in the balance between pro- and anti-inflammatory cytokines may be one of the most important mechanisms of myocardial protection caused by sevoflurane.

Free radicals, antioxidants, and neurologic injury: possible relationship to cerebral protection by anesthetics

Oxygen-centered free radicals cause brain injury associated with trauma and stroke. These reactive oxygen species may be detoxified by endogenous antioxidants, but cell death occurs after antioxidants become depleted. General anesthetics penetrate into brain parenchyma, where they may abrogate oxidative injury to neurons by several mechanisms that prevent the initiation of free radical chain reactions or terminate the propagation of highly reactive radicals. First, general anesthetics may inhibit free radical generation because these drugs slow cerebral utilization of oxygen and glucose, inhibit oxidative metabolism in neutrophils, and prevent redox changes in hemoglobin. Second, antioxidant anesthetics, such as thiopental and propofol, directly scavenge reactive oxygen species and inhibit lipid peroxidation. Finally, anesthetics may prevent the elevation of extracellular glutamate concentration and inhibit the activation of excitatory glutamatergic receptors that augment oxidative stress after ischemia.

Spinal anaesthesia but not general anaesthesia enhances neutrophil biocidal activity in hip arthroplasty patients

The purpose of this study was to compare neutrophil cidal activity during general or spinal anaesthesia. Assays were performed on neutrophils extracted from the blood of patients after surgery had been under way for one hour. First, the ability of the neutrophils to kill a standard laboratory strain of S. aureus was examined. Neutrophils extracted from the blood during surgery in the spinal anaesthetic group and incubated with the staphylococci for one hour killed twice as many bacteria than those from two groups of patients that received halothane or isoflurane general anaesthesia (P < 0.05). This effect persisted, to a lesser extent, in the spinal group neutrophils after two hours of incubation with the bacteria. Second, neutrophils from patients under the same conditions of surgery and anaesthesia were tested to examine the effect of the different anaesthetic techniques on neutrophil biocidal mechanisms. Neutrophils extracted during surgery in the spinal group released more superoxide in response to phorbol-12-myristate-13-acetate (PMA) than those from both groups of patients that received general anaesthesia (P < 0.05). It is concluded that there is an increased state of reactivity of the neutrophil cell membrane NADPH oxidase system in patients receiving spinal anaesthesia than in patients receiving general anaesthesia.

[Do halogenated anesthetics protect from ischemic and reperfusion myocardial injuries?]

Ischaemia and reperfusion of the myocardium are associated with cellular injuries leading to a decrease of contractile function and the occurrence of arrhythmias. As reperfusion of an ischaemic heart results in an intracellular overload of calcium, a calcium blocking agent pretreatment has been shown to exert a protective effect. By altering myocardial calcium fluxes, volatile anesthetics might also protect the myocardium from ischaemic damage and reperfusion injuries. A beneficial effect of volatile anesthetics on the ischaemic myocardium has been shown in numerous studies. These agents decrease the severity of ischaemia as well as the incidence of reperfusion arrhythmias and improve recovery of myocardial mechanics during reperfusion. They also preserve myocardial energetics and protect from oxygen-derived free radicals injury. However, some studies do not support these protective effects. The wide discrepancy between the various protocols might explain the discrepancy of the results. Enflurane and halothane seem to be more efficient than isoflurane. This cannot only be explained by different cardiovascular effects, but also by a specific effect on myocardial cells. Halothane and enflurane mainly decrease intracellular calcium availability by a direct effect on sarcoplasmic reticulum, while isoflurane only decreases the transsarcolemnal calcium entry. Enflurane and halothane have more beneficial effects than isoflurane on free radicals induced myocardial injuries. In conclusion, despite a wide diversity between the different studies, halothane and enflurane have better protective properties against ischaemia and reperfusion myocardial injuries than isoflurane.