Update on anaesthesia and the immune response

Nonexperimental Xenobiotics: Unintended Consequences of Intentionally Administered Substances in Terrestrial Animal Models

Review of the use of nonexperimental xenobiotics in terrestrial animal models and the potential unintended consequences of these compounds, including drug-related side effects and adverse reactions.

General anesthesia might be associated with early periprosthetic joint infection: an observational study of 3,909 arthroplasties

Background and purpose - Periprosthetic joint infection (PJI) remains a devastating complication following total knee or total hip arthroplasty (TKA/THA). Nowadays, many studies focus on preventive strategies regarding PJI; however, the potential role of anesthesia in the development of PJI remains unclear.Patients and methods - All consecutive patients undergoing elective primary unilateral TKA or THA from January 2014 through December 2017 were included. Exclusion criteria included femoral fractures as the indication for surgery and previously performed osteosynthesis or hardware removal on the affected joint. Age, sex, BMI, ASA classification, type of arthroplasty surgery, type of anesthesia, duration of surgery, smoking status, and intraoperative hypothermia were recorded. Propensity score-matched univariable logistic regression analysis was used to control for allocation bias.Results - 3,909 procedures consisting of 54% THAs and 46% TKAs were available for analysis. 42% arthroplasties were performed under general anesthesia and 58% under spinal anesthesia. Early PJIs were observed in 1.7% of the general anesthesia group and in 0.8% in the spinal anesthesia group. The multivariable logistic regression model demonstrated an odds ratio for PJI of 2.0 (95% CI 1.0-3.7) after general anesthesia relative to the propensity score-matched patients who received spinal anesthesia.Interpretation - These results suggest a potential association between general anesthesia and early PJI. Future research using large-scale data is required to further elucidate this clinically relevant association.

Serum protein changes during cardiopulmonary bypass: implications for host defence

A reduction in host defence capability, with increased risks of infection, occurs after open-heart surgery to a greater degree than after nonbypass surgery. Our costs for postoperative infections are large, about 15% of the total cost of open-heart surgery; better understanding of factors contributing to infection might allow reduction in these costs. Disturbance of the mechanisms involved in the handling of haemoglobin and iron may be among such factors, since free iron is a facultative requirement for the growth of all micro-organisms. We evaluated the change in serum proteins, particularly haptoglobin, during cardiopulmonary bypass. This study, in eight patients undergoing uncomplicated aortocoronary bypass employing a bubble oxygenator with haemodilution, and without clinical evidence of haemolysis, showed that free, unbound haptoglobin, evaluated by agarose gel electrophoresis, disappeared and was replaced by haemoglobin-bound haptoglobin within minutes of going on bypass. Such changes were not seen in three control patients who underwent comparably extensive surgery without bypass or in-bypass controls, in whom blood was evaluated after dilution with oxygenator prime. The disappearance of free haptoglobin and the possible disturbance of iron transport may have implications for host defences after bypass.

Effects of Propofol and Midazolam on the Inflammation of Lungs after Intravenous Endotoxin Administration in Rats

OBJECTIVE

Pulmonary complications are important sepsis (such as ARDS, diffuse pneumonia). Acute respiratory distress syndrome (ARDS) is characterized by the extensive migration of neutrophils into alveoli of the lungs. Propofol and midazolam are the most widely used agents for sedation in intensive care units. Aimed to investigate the effects of anaesthesia with propofol and midazolam on measured hemodynamic variables and neutrophil migration induced by Escherichia Coli endotoxin (ECE) in pulmonary viscera.

MATERIALS AND METHODS

Forty Sprague Dawley male rats were randomly assigned to four groups: Thiopental Sodium 30 mg/kg was administered intraperitoneally to anesthetize the rats. They were ventilated via tracheotomy. Femoral artery was cannulated for the measurement of continuous blood pressure and gases. Group C was the control. After the administration of 1 mL/kg 0.9% NaCL, infusion began at 1 mL/kg/h rate. In Group E 15 mg/kg lipopolysaccharide derived from ECE was administered iv. In Group PE, after a bolus dose of 10 mg/kg propofol and 15 mg/kg ECE, 10 mg/kg/h infusion was applied. In Group ME, after 0.1 mg/kg midazolam bolus dose and 15 mg/kg ECE administration, 0.1 mg/kg/h infusion was administered iv. Rats were sacrified by iv potassium chloride. The lungs were then removed, fixed in 10% buffered formalin for 3 days and embedded in paraffin. They were graded on a scale of 0-3 according to the aggregation of neutrophils.

RESULTS

There was intense neutrophil migration in Group E (grade 2, 3). However, although mild neutrophil migration was obtained in 70% of the rat lungs in Group ME (grade 1, 2), it was recorded in only 30% of Group PE (grade 1).

CONCLUSION

The sepsis model induced by ECE and compared with midazolam, propofol anaesthesia is associated with less neutrophil infiltration. In the light of the literature, propofol attenuate the free-radical-mediated lipid peroxidation and systemic inflammation in patients.

Anaesthetics modulate tumour necrosis factor alpha: effects of L-carnitine supplementation in surgical patients. Preliminary results

Both anaesthetics and surgical trauma could strongly affect the production of tumour necrosis factor alpha (TNFalpha). During in vitro experiments the authors found that anaesthetics modulate the production of TNFalpha by peripheral blood mononuclear cells. Notably, Pentothal strongly increased the production of the cytokine as compared to both lipopolysacchride treated and control mononuclear cells, whereas in supernatants from Leptofen driven mononuclear cells TNFalpha was strongly reduced. On the other hand, Pavulon did not significantly affect the cytokine production. In the in vivo study, in an attempt to ameliorate the metabolic response to surgical trauma, L-carnitine was administered to 20 surgical patients, then the circulating TNFalpha was measured. The results indicate that the levels of circulating TNFalpha were strongly increased following surgery and that L-carnitine administration resulted in a strong reduction of TNFalpha. Thus, the data suggest that L-carnitine could be helpful in protecting surgical patients against dysmetabolism dependent on dysregulated production of TNFalpha.

Immunization and anesthesia - an international survey

BACKGROUND

There is no direct evidence of any major interaction between immunization and commonly used anesthetic agents and techniques in children, but it is possible that immunosuppression caused by anesthesia and surgery may lead to decreased vaccine effectiveness or an increased risk of complications. In addition, diagnostic difficulty may arise if a recently immunized child suffers from postoperative pyrexia or malaise.

AIM

The aim of this study was to ascertain anesthetists' attitudes and practices regarding anesthesia and immunization.

METHODS

We conducted an international survey of members of the Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI) and the Society for Paediatric Anaesthesia of New Zealand and Australia (SPANZA).

RESULTS

Two hundred and ninety-six (52.1%) APAGBI and 86 (49.4%) SPANZA responses were analyzed. There was no consensus of approach to this theoretical risk among respondents. In total, 60% of respondents would anesthetize a child for elective surgery within 1 week of receiving a live attenuated vaccine, but 40% would not. Few hospitals have formal policies on this issue and government guidance is based on a lack of evidence for adverse events rather than positive evidence of safety.

CONCLUSIONS

There is a theoretical risk associated with anesthesia and surgery in recently immunized children. An international postal survey failed to find a consensus to this risk among pediatric anesthetists. From a risk management perspective, a review of the available evidence suggests that it would be prudent to adopt a cautious approach where the timing of elective surgery is discretionary. We therefore recommend that elective surgery and anesthesia should be postponed for 1 week after inactive vaccination and 3 weeks after live attenuated vaccination in children.

The effect of anaesthesia and surgery on plasma cytokine production

The aim of this study was to investigate cytokine production in response to anaesthesia [total intravenous anaesthesia (TIVA) with propofol, sufentanil and atracurium] and surgery (laparoscopic vs. open cholecystectomy). Forty adult patients, ASA I-II, undergoing elective laparoscopic (group 1) or open (group 2) cholecystectomy were studied. Venous blood samples for measurement of interleukin (IL)-1beta, IL-2, IL-4, IL-6, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were taken before the induction of anaesthesia, pre-incisionaly, at the end of anaesthesia and surgery and 24-h postoperatively. Pre-incisionaly, in both groups, IL-1beta, IL-4, IL-6, TNF-alpha and IFN-gamma did not show a significant change, whereas IL-2 showed a significant decrease (p < 0.005 in group 1 and p < 0.001 in group 2) compared with pre-induction levels. By the end of anaesthesia and surgery, IL-1beta, IL-2, IL-4, IL-6 and TNF-alpha showed a significant increase in group 2 (p < 0.005 for IL-1beta, IL-2 and IL-4, and p < 0.05 for IL-6 and TNF-alpha); while in group 1, only IL-2 showed a significant increase (p < 0.01) and IFN-gamma showed a significant decrease (p < 0.05) compared with pre-incisional levels. By 24-h postoperatively, IL-1beta, IL-4, IL-6 and TNF-alpha had decreased significantly in group 2 (p < 0.005 for IL-4 and p < 0.05 for the others); whereas in group 1, IL-2 and IFN-gamma showed a significant increase (p < 0.005) compared with the end of anaesthesia and surgery level. In conclusion, TIVA with propofol, sufentanil and atracurium does not seem to have a significant effect on IL-1beta, IL-4, IL-6, TNF-alpha and IFN-gamma release. IL-2 was the only cytokine to show a significant decrease due to the effect of anaesthesia alone in both groups. The cytokine response to open cholecystectomy stimulated both the pro-inflammatory (IL-1beta, IL-6 and TNF-alpha) and the anti-inflammatory (IL-4) components, while this response was absent in laparoscopic cholecystectomy.

Immune alterations associated with epidural analgesia for labor and delivery

PURPOSE

Epidural analgesia is frequently used for the laboring woman and commonly regarded as safe. The association of epidural analgesia with fever, in the absence of infection, in this population can result in unnecessary sepsis workups in both neonates and mothers. Studies in other populations of patients have found that epidural anesthesia may be associated with alterations in white blood cell count parameters. This study was designed to determine if epidural analgesia is associated with alterations in immune profile or immune function in healthy afebrile postpartum women.

DESIGN

This prospective quasi-experimental study examined a convenience sample of normal afebrile postpartum women in two groups for differences in immune profile and immune function based on whether they received epidural analgesia during labor and delivery.

METHODS

Mothers who agreed to participate in the study and met inclusion criteria had blood drawn for immune profile and immune function studies within 24 hours of their delivery. This study looked at immune phenotypic profile, lymphocyte proliferative response, and NK lysis assays.

RESULTS

No differences in immune profile or immune function were found based on administration of epidural analgesia.

CLINICAL IMPLICATIONS

Nurses can be confident that the white blood cell count and other phenotypic measures of leukocytes are not affected by epidural analgesia. Thus the epidural analgesic technique appears not to alter immune measures of infection in postpartum women. In evaluating fever in postpartum mothers and neonates, nurses should consider prior receipt of epidural analgesia and measures of immune profile. In addition to fever and white blood cell counts, other signs and symptoms of infection should also be evaluated in postpartum women when infection is suspected.

Anaesthetic management of caesarean section in a patient with myelodysplastic syndrome

PURPOSE

This case report describes the anaesthetic management for Caesarean section in a patient with myelodysplastic syndrome.

CLINICAL FEATURES

A woman with myelodysplastic syndrome underwent Caesarean section on two occasions. The first Caesarean section was performed at age 20 yr using general anaesthesia with nitrous oxide-oxygen and fentanyl. In her second pregnancy at 25 yr, there was severe pancytopenia at 28-wk gestation with a leukocyte count 3.6 x 10(9).L-1, erythrocyte count 1.2 x 10(12).L-1, haemoglobin 50 g.L-1, haematocrit 14.7% and platelet count 51 x 10(9).L-1. Following leukocyte poor red cells and platelet transfusion, general anaesthesia was maintained with nitrous oxide-oxygen-sevoflurane and fentanyl. Both operations were uneventful and healthy infants were delivered.

CONCLUSION

It is important to have a team approach (anaesthetist, obstetrician and haematologist) for the perianaesthetic management of patients with myelodysplastic syndrome. An exact assessment of the haematological condition, the need for prophylactic treatment and anaesthetic management should be determined for each individual patient.

Halothane and isoflurane enhance melanoma tumour metastasis in mice

PURPOSE

To investigate the incidence of tumour metastasis from B16 melanoma tumour cells in experimental animals following exposure to equipotent concentrations of halothane or isoflurane, and to differentiate if exposure to one anaesthetic resulted in greater metastases than the other.

METHODS

Experimental animals (C57B1 mice), were randomized to receive 1.3 MAC hours of halothane or isoflurane anaesthesia. The control group of animals received oxygen alone under identical conditions. Fifteen minutes after completion of anaesthesia, control and experimental groups were given 1 x 10(5) B16 melanoma cells intravenously. After 21 days, all animals were autopsied, and the metastatic nodules in their lungs were counted. The difference in the numbers of metastatic nodules between control and experimental groups of animals was analyzed for significance by the Mann Whitney "U test".

RESULTS

More metastases were observed in the animals exposed to halothane (37.28 +/- 5.08, P < 0.0001), or isoflurane anaesthesia (28.24 +/- 4.07, P < 0.0014) than in the control animals (12.22 +/- 1.52).

CONCLUSION

Exposure to halothane or isoflurane anaesthesia increased the number of pulmonary metastases in C57B1 mice compared with the control groups but there was no difference in metastases among animals treated with halothane or isoflurane.

Effect of general anaesthesia and surgery on neutrophil function

The effects of general anaesthesia and surgical trauma on neutrophil function were studied in 60 female ASA 1 and 2 patients undergoing anaesthesia for gynaecological surgery. Patients were divided into three groups depending on the degree of trauma and duration of surgery. Group 1 (n = 15) were patients for dilatation and curettage (minor surgical trauma) and were given 2% halothane. Group 2 (n = 30) had laparoscopic surgery (moderate surgical trauma) and received either 0.5% halothane or 1% enflurane. Group 3 (n = 15) were those having hysterectomy (major surgical trauma) and received 0.5% halothane for a longer duration. Venous samples were taken 30 min before anaesthesia (control value), 10 min after induction of anaesthesia, 10 min after the start of surgery, 30 min after the end of anaesthesia and 24 h later. Phagocytic index, nitroblue tetrazolium reduction test, total leucocyte count, and differential leucocyte counts were performed on each sample. Data were analysed by paired t-test to compare findings in the same patient and by unpaired t-test for differences between groups. Anaesthesia with halothane 0.5% to 2% caused a dose-related depressant effect on leucocyte function which reversed. Enflurane 1% on the other hand caused significantly greater depression of leucocyte function compared with 0.5% halothane which persisted during the recovery period and recovered on the first postoperative day. Total leucocyte counts also showed a fivefold increase in the major surgery groups.

Anesthetic agents induce human mononuclear leucocytes to release cytokines

Studies were carried out on the ability of some anesthetic agents (Propofol, Dormicum, Ketalar and Penthotal) to induce the release of cytokines by human monocytes and lymphocytes in vitro. All anesthetic agents tested at hematic concentrations reached during anesthetic administration cause an increase in the production of Tumor necrosis factor (TNF) from human monocytes; the increase is 4-5 times greater than controls. The greatest Interleukin -1 alpha (IL-1 alpha) production increase was induced by Propofol. The release of Interleukin -6 (IL-6) is notably increased by Ketalar (about 10 times greater than controls). In the presence of different anesthetic agents, human lymphocytes release Interleukin -4 (IL-4) and Interferon gamma- (IFN-gamma). Penthotal and Ketalar increase IL-4 production which appears quite high compared to that obtained with Con A used as standard challenge. Propofol induce IL-4 release which is about the same as that seen with Con A. IFN-gamma is released in high quantities by lymphocytes treated with Propofol. Dormicum, Ketalar and Penthotal induce non-significant increase of IFN-gamma release. The results concern the choice of anesthetic, in relation to its action on host immune response. This aspect is particularly interesting in immunocompromised host.

Inhibition by halothane, but not by isoflurane, of oxidative response to opsonized zymosan in whole blood

In an attempt to clarify some apparent discrepancies in reports of the effects of anesthetic agents upon granulocyte function, we studied the effects of halothane and isoflurane, using techniques that allowed us to perform the assays in and in sealed vials to prevent volatile gas evolution: assay gas concentrations were measured, rather than inferred. Chemiluminescence, superoxide production, and hydrogen peroxide production were assessed after presentation of opsonized zymosan as a phagocytic stimulus. Incubation with halothane led to a highly statistically significant dose-related inhibition of chemiluminescence (maximum 66%), H2O2 production (67%) and .O2- production (61%), within the concentration range observed in blood from patients undergoing general anesthesia. In contrast, the presence of isoflurane led to no statistically significant changes in any of the functions measured. Cells harvested from patients undergoing elective halothane anesthesia showed the same functional inhibition, but for quantitative differences likely due to the inability to control for dilution effects in clinical samples. It has been suggested that halothane anesthesia may be associated with excess mortality in septic patients; although the results we report are readily reversible, their presence during a prolonged anesthesia could be harmful in a patient who is not immunologically normal and/or who is already infected. Careful clinical trials will be necessary to determine if isoflurane is a superior agent in this context.

Suppression of neutrophil migration and chemiluminescence is due to the sulphur atom in the thiobarbiturate molecule

In this study the hypothesis was tested that the substituent at the C 2 position of the barbiturate molecule is crucial for the obvious differences in inhibitory potencies between various barbiturates with respect to neutrophil functions in vitro. Using isolated neutrophils from healthy volunteers, the comparative effects of two pairs of sulphur or oxygen-substituted analogues on chemiluminescence, random and chemotactic migration were examined. Five other i.v. barbiturates were also tested in the chemiluminescence assay. The key observation with all the assay systems was that the oxybarbiturates proved ten to a hundredfold less suppressive than their sulphurated analogues or the other thiobarbiturates. Thus, enhanced inhibitory potency was dependent on the presence of the sulphur atom in the barbiturate molecule and could no longer be explained exclusively on the basis of divergent physicochemical features.