Effect of anesthesia and surgery on plasma cytokine levels

Surgical stabilization of rib fractures is associated with improved survival but increased acute respiratory distress syndrome

Background

How the surgical stabilization of rib fractures after trauma affects the development of acute respiratory distress syndrome and impacts survival has yet to be determined in a large database. We hypothesized that surgical stabilization of rib fractures would not decrease the incidence of acute respiratory distress syndrome.

Methods

The National Trauma Data Bank was queried for all traumatic rib fractures in 2016. Patients were divided into groups with single rib fractures, multiple rib fractures, and flail chest. Nonoperative therapy was compared with stabilization of rib fractures of 1 to 2 ribs or 3+ ribs.

Results

There were 114,972 total patients with rib fractures meeting inclusion criteria, with 5,106 (4.4%) having flail chest, 24,726 (21.5%) having single rib fractures, and 85,140 (74.1%) having multiple rib fractures. Those with flail chest (15.9%) were most likely to get rib plating in comparison to multiple rib fractures (0.9%) and single rib fractures (0.2%); P < .001. On logistic regression, surgical stabilization of rib fractures 1 to 2 ribs (odds ratio: 0.17, 95% confidence interval: 0.10–0.28) or 3+ ribs (odds ratio: 0.17, 95% confidence interval: 0.11–0.28), with nonoperative therapy as the reference was associated with survival. Variables associated with mortality included increasing age, male sex, increasing injury severity score, decreased Glasgow coma scale, requirement of transfusions, and hypotension on admission. Surgical stabilization of rib fractures 3+ ribs (odds ratio: 2.30, 95% confidence interval: 1.58–3.37) was associated with acute respiratory distress syndrome but not 1 to 2 ribs (odd ratio: 1.55, 95% confidence interval: 0.97–2.48). On logistic regression of only patients with flail chest, stabilization of rib fractures was associated with decreased mortality but not increased risk of acute respiratory distress syndrome.

Conclusion

The increased risk of acute respiratory distress syndrome should be considered in the preoperative assessment for stabilization of rib fractures.

Effects of general and spinal anesthetic techniques on endothelial adhesion molecules in cesarean section

Background

The aim of this study was to investigate the effects of anesthetic techniques used during general anesthesia (GA) and spinal anesthesia (SA) on endothelial adhesion molecules in the fetal circulation of healthy parturients undergoing elective cesarean section.

Methods

Patients were randomly assigned to either the general anesthesia (n = 20) or spinal anesthesia (n = 20) group. Maternal and cord blood neopterin, sE-selectin, and sL-selectin levels were measured in both groups.

Results

Cord blood neopterin concentrations in the SA group were not different from those in the GA group, but maternal neopterin levels in the SA group were different from those in the GA group. Maternal blood levels of sE-selectin and sL-selectin were not different between the two groups. Similarly, the cord blood levels of sE-selectin and sL-selectin were not different between the two groups. We found an increased inflammatory process in the fetal circulation depending on the anesthetic method used.

Conclusions

These results indicate the effects of general and spinal anesthetic techniques on serum sL-selectin, sE-selectin, and neopterin levels in neonates and parturients undergoing elective cesarean section. sE-selectin and neopterin concentrations and leukocyte counts were higher in the fetal circulation than in the maternal circulation during both GA and SA.

[Postoperative cognitive dysfunction (POCD): strategy of prevention, assessment and management]

The femoral neck fracture is a major cause of morbidity and mortality in the elderly. The etiology of cognitive impairment observed in this population of aged patient seems to be multifactorial. In the strategy of prevention, elderly patient must have the clearer information dealing with the postoperative cognitive dysfunction. This would reduce the incidence of POCD and some cognitive complaints, which often reflect the anxiety of the elderly patient facing the possibility of cognitive impairment. During the anaesthesia consultation, it seems important to assess the cognitive function of this elderly patient (like using neuropsycholgical scale as the MMSE) and to identify associated risk factors of cognitive dysfunction. The management of cognitive disorders should be multidisciplinary, the anesthesiologist being the main referent, in collaboration with the geriatrician and the surgeon. In the clinical setting of femoral neck fracture in the elderly, this multimodal management (pain, nutrition, functional rehabilitation to make these patients autonomous as quickly as possible), seems to improve the functional prognosis and to have the observed POCD decreased.

A dynamic view of trauma/hemorrhage-induced inflammation in mice: principal drivers and networks

BACKGROUND

Complex biological processes such as acute inflammation induced by trauma/hemorrhagic shock/ (T/HS) are dynamic and multi-dimensional. We utilized multiplexing cytokine analysis coupled with data-driven modeling to gain a systems perspective into T/HS.

METHODOLOGY/PRINCIPAL FINDINGS

Mice were subjected to surgical cannulation trauma (ST) ± hemorrhagic shock (HS; 25 mmHg), and followed for 1, 2, 3, or 4 h in each case. Serum was assayed for 20 cytokines and NO(2) (-)/NO(3) (-). These data were analyzed using four data-driven methods (Hierarchical Clustering Analysis [HCA], multivariate analysis [MA], Principal Component Analysis [PCA], and Dynamic Network Analysis [DyNA]). Using HCA, animals subjected to ST vs. ST + HS could be partially segregated based on inflammatory mediator profiles, despite a large overlap. Based on MA, interleukin [IL]-12p40/p70 (IL-12.total), monokine induced by interferon-γ (CXCL-9) [MIG], and IP-10 were the best discriminators between ST and ST/HS. PCA suggested that the inflammatory mediators found in the three main principal components in animals subjected to ST were IL-6, IL-10, and IL-13, while the three principal components in ST + HS included a large number of cytokines including IL-6, IL-10, keratinocyte-derived cytokine (CXCL-1) [KC], and tumor necrosis factor-α [TNF-α]. DyNA suggested that the circulating mediators produced in response to ST were characterized by a high degree of interconnection/complexity at all time points; the response to ST + HS consisted of different central nodes, and exhibited zero network density over the first 2 h with lesser connectivity vs. ST at all time points. DyNA also helped link the conclusions from MA and PCA, in that central nodes consisting of IP-10 and IL-12 were seen in ST, while MIG and IL-6 were central nodes in ST + HS.

CONCLUSIONS/SIGNIFICANCE

These studies help elucidate the dynamics of T/HS-induced inflammation, complementing other forms of dynamic mechanistic modeling. These methods should be applicable to the analysis of other complex biological processes.

IL-10 deficiency augments acute lung but not liver injury in hemorrhagic shock

In hemorrhagic shock and trauma, patients are prone to develop systemic inflammation with remote organ dysfunction, which is thought to be caused by pro-inflammatory mediators. This study investigates the role of the immuno-modulatory cytokine IL-10 in the development of organ dysfunction following hemorrhagic shock. Male C57/BL6 and IL-10 KO mice were subjected to volume controlled hemorrhagic shock for 3h followed by resuscitation. Animals were either sacrificed 3 or 24h after resuscitation. To assess systemic inflammation, serum IL-6, IL-10, KC, and MCP-1 concentrations were measured with the Luminex multiplexing platform; acute lung injury (ALI) was assessed by pulmonary myeloperoxidase (MPO) activity and lung histology and acute liver injury was assessed by hepatic MPO activity, hepatic IL-6 levels, and serum ALT levels. There was a trend towards increased IL-6 and KC serum levels 3h after resuscitation in IL-10 KO as compared to C57/BL6 mice; however this did not reach statistical significance. Serum MCP-1 levels were significantly increased in IL-10 KO mice 3 and 24 h following resuscitation as compared to C57/BL6 mice. In IL-10 KO mice, pulmonary MPO activity was significantly increased 3 h following resuscitation and after 24 h histological signs of acute lung injury were more apparent than in C57/BL6 mice. In contrast, no significant differences in any liver parameters were detected between IL-10 KO and C57/BL6 mice. Our data indicate that an endogenous IL-10 deficiency augments acute lung but not liver injury following hemorrhagic shock.

The role of fracture-associated soft tissue injury in the induction of systemic inflammation and remote organ dysfunction after bilateral femur fracture

OBJECTIVES

The storage of preformed cytokines in soft tissue as well as the immunocompetence of adipocytes has been reported. We hypothesized that fracture-associated soft tissue injury plays a pivotal role in the induction of systemic inflammation and remote organ dysfunction after fracture.

MATERIALS AND METHODS

Male C57/BL6 mice sustained either severe soft tissue injury to both thighs (STI), bilateral femur fracture with minimal soft tissue injury (Fx), or the combination of both (Fx+STI) and were euthanized 6 hours after injury. Serum cytokine concentrations were measured using the Luminex multiplexing platform, and serum ALT levels were measured with the Vitros 950 Chemistry System. Hepatic myeloperoxidase activity, a marker for polymorphonuclear cell infiltration, and hepatic IL-6 levels were determined using ELISA kits. Hepatic permeability changes were assessed via measurement of edema formation.

RESULTS

STI as well as Fx both induced significantly elevated serum IL-6 and L-10 levels as compared with Sham animals (P < 0.05). Further, serum IL-6 and IL-10 levels were significantly higher after STI as compared with Fx (P < 0.05). Serum KC and MCP-1 levels were significantly elevated after STI but not after Fx (P < 0.05). STI as well as Fx resulted in significantly increased serum ALT levels and hepatic polymorphonuclear cell infiltration. The combination of both injuries resulted in further increased systemic inflammatory mediators as well as marked liver inflammation and dysfunction represented by significantly elevated serum ALT levels, hepatic polymorphonuclear cell infiltration, hepatic IL-6 concentrations, and hepatic edema formation as compared with Sham animals (P < 0.05).

CONCLUSIONS

Although STI and Fx both induced a systemic inflammatory response, this was more pronounced after STI. However, the combination of both injuries (Fx+STI) was required to induce marked liver dysfunction. Our data indicate that fracture-associated soft tissue injury is a major contributor to the systemic inflammatory response after bilateral femur fracture. This should be recognized especially in multiply injured patients, who are susceptible to systemic inflammation with remote organ dysfunction.

Expression and characterization of the recombinant swine interleukin-6

The swine interleukin-6 (SwIL-6) cDNA was cloned by RT-PCR and each expression system of recombinant SwIL-6 in Escherichia coli, insect cells, and mammalian cells was developed. Recombinant SwIL-6 produced in bacteria was applied for generation of the polyclonal antibodies. The rSwIL-6 was purified from supernatant of insect cells with a Q-sepharose or anti-SwIL-6 monoclonal antibody based immunoaffinity column. The antibodies showed that the molecular weight of rSwIL-6 was approximately 26kDa in E. coli, 25, 26, 30kDa in insect cells, and 26 and 30kDa in mammalian cells. These variations of molecular weight were probably due to the different modifications of glycosylation. All these recombinant proteins retained the antigenicity and biological activity on 7TD1 mouse cells.

Acute phase response in laparoscopic and open colectomy in colon cancer: randomized study

PURPOSE

All types of trauma to the organism produce a systemic response that is proportional to the severity of the lesion caused. The more rapid clinical recovery during the postoperative period of patients undergoing laparoscopic-assisted colectomy vs. patients receiving conventional surgery suggests that laparoscopic surgery produces less surgical trauma. The aim of this randomized, prospective study was to compare acute phase postoperative response in patients diagnosed with colon neoplasm undergoing open segmentary colectomy vs. laparoscopic-assisted colectomy.

METHODS

From June 1994 to July 1997 the results of 97 patients (58 submitted to open colectomy and 39 undergoing laparoscopic-assisted colectomy) were analyzed. Blood determinations of cortisol, prolactin, C-reactive protein and interleukin-6 were performed before surgery and at 4, 12, 24, and 72 hours after surgery.

RESULTS

The plasma levels of cortisol and prolactin were higher in the postoperative period with both surgical techniques with no significant differences being observed. The levels of interleukin-6 achieved a maximum peak at 4 hours after surgery, later showing a decrease and practically achieving basal levels at 72 hours in both groups. The levels of interleukin-6 were higher with significant differences at 4, 12, and 24 hours in the patients undergoing open colectomy. The plasma levels of C-reactive protein were significantly lower at 72 hours in patients receiving laparoscopic-assisted colectomy.

CONCLUSIONS

The results obtained in this randomized, prospective study suggest that acute phase systemic response is attenuated in patients undergoing laparoscopic-assisted colectomy in comparison with patients receiving open colectomy.

The effect of halothane and isoflurane on plasma cytokine levels

The aim of this study was to investigate the effect of halothane vs. isoflurane on cytokine production during minor elective surgery. Forty adult patients, ASA I-II were randomly allocated to receive halothane or isoflurane. Venous samples for interleukin (IL)-1beta, IL-2, IL-6, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were taken before anaesthesia, before incision, at the end of anaesthesia and 24 h postoperatively. In both groups, IL-6 and TNF-alpha levels remained low throughout the study period. Before incision, in both groups IL-1beta and IFN-gamma showed a decrease (p<0.01 for IL-1beta in isoflurane group and p<0.05 for the others) compared with pre-induction. By the end of anaesthesia and surgery, IL-1beta had increased significantly (p<0.05) and IFN-gamma had decreased significantly (p<0.05) in both groups compared with pre-incisional levels. By 24 h postoperatively in both groups, IL-1beta had decreased significantly (p<0.05), whereas IFN-gamma had increased significantly (p<0.05) compared with the end of anaesthesia and surgery level. Pre-incisionally, IL-2 increased in the halothane group (p<0.01), whereas it decreased significantly in the isoflurane group (p<0.001) compared with the pre-induction level. By the end of anaesthesia and surgery and by 24 h postoperatively, IL-2 had decreased significantly in the halothane group (p<0.001), whereas it increased significantly in the isoflurane group (p<0.001) compared with pre-incision and end of anaesthesia and surgery levels, respectively.

Changes in plasma IL-1beta, TNF-alpha and IL-6 after total hip replacement surgery in general or regional anaesthesia

Different anaesthetic methods influence the neuro-immuno-endocrine biologic responses to surgery and may thus possibly interfere with the postoperative course and development of complications. The neuroendocrine system is closely related to the cytokine network. In this study, the effects of general anaesthesia (n=6) and regional spinal/epidural anaesthesia (n=6) on the cytokine response (IL-1beta, TNFalpha, IL-6) to uncemented total hip replacement surgery were evaluated. The postoperative clinical course was uneventful in every case. In both groups, only very low values of plasma IL-beta were measured perioperatively, whereas plasma IL-6 increased postoperatively with peak values 4 h after surgery. The changes in plasma TNF-alpha were not significant. No significant differences in plasma TNF-alpha or IL-6 were found between patients operated in general or in regional anaesthesia. This suggests minor influence of plasma cytokines on the possible beneficial effects of regional anaesthesia on the clinical course after surgery in low risk patients. There were slightly higher TNF-alpha and IL-6 levels after the operation and significantly lower cortisol levels during the operation in the regional anaesthesia group compared to the general anaesthesia group, giving rise to a significant inverse correlation between peak values of IL-6 and peak values of cortisol. This supports the theory that after surgery the inhibitory effect of cortisol on monocyte cytokine production overrides adrenergic stimulation.

Biphasic changes in left ventricular function during hyperdynamic endotoxemia

Cardiac contractility was studied in a clinically relevant conscious swine model simulating human hemodynamics during endotoxemia. The slope of the end-systolic pressure-volume relationship [end-systolic elastance (EES)] was used as a load-independent contractility index. Chronic instrumentation in 10 pigs included two pairs of endocardial ultrasonic crystals for measuring internal major and minor axial dimensions of the left ventricle, a micromanometer for left ventricular pressure measurement, and a thermodilution pulmonary artery catheter. After a 10-day recovery period, control measurements of cardiac hemodynamic function were obtained. The following week, Escherichia coli endotoxin (10 micrograms . kg-1. h-1) was administered intravenously for 24 h. EES increased 1 h after endotoxin infusion and decreased beyond 7 h. The later hemodynamic changes resembled human cardiovascular performance during endotoxemia more closely than the changes during the acute phase. EES decreased in the later phase. A similar biphasic response of EES has been reported during a tumor necrosis factor-alpha (TNF) challenge. Even though plasma TNF was highest at 1 h and declined thereafter in this study, no consistent relationship between TNF and EES was identified, and TNF levels did not correlate directly with the changes in EES.

Perioperative cytokine release during coronary artery bypass grafting in patients of different ages

Surgical interventions and cardiopulmonary bypass (CPB) induce a systemic inflammatory response with cytokine release. Ageing is perceived as a process of impaired immune functions: IL-1beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) secretion are increased while IL-2 release is reduced in advanced age. At present, little information is available about perioperative immune reactions at different stages of ageing. The aim of the present study was to compare IL-6, IL-1beta, TNF-alpha, IL-10 and soluble IL-2 receptor (sIL-2R) in younger and older patients undergoing cardiac surgery. Male patients (n = 14) undergoing elective coronary artery bypass grafting (CABG) surgery employing CPB with moderate hypothermia were divided into two groups according to their age: group 1 included seven patients < 50 years old, group 2 included seven patients > 65 years old. All patients received general anaesthesia using a balanced technique with sufentanil, isoflurane and midazolam. Blood samples were collected pre-operatively (T1); intra-operatively during CPB (T2); post-operatively on the day of surgery (T3); on the first post-operative day (T4). Blood concentrations of IL-6, IL-1beta, IL-10, TNF-alpha and sIL-2R were measured using commercially available ELISA kits and corrected for plasma cell volume. Statistical analysis was performed by non-parametric analysis of variance and Mann-Whitney U-test. Significance level was set to P<0.05. There were no statistically significant differences in the perioperative release of TNF-alpha, IL-6, IL-1beta, IL-10 and sIL-2R among the two groups. We conclude that the perioperative course of cytokine release in patients undergoing CABG surgery with CPB and comparable perioperative management does not significantly differ in the two age groups.

The nonspecific inflammatory response to injury

PURPOSE

The role of the nonspecific inflammatory response in causing injury related to surgery has become better understood over the last decade. There are complex interactions between neutrophils, cytokines and nitric oxide metabolites that may cause organ injury following surgery. The purpose of this review is to summarize some of the processes causing injury through these nonspecific pathways.

METHODS

A review of the medical and anaesthetic literature related to inflammation, neutrophils and pro-inflammatory cytokines were performed using Medline. Bibliographies of relevant articles were searched and additional articles were then selected and reviewed.

RESULTS

Pro-inflammatory cytokines, such as tumour necrosis factor, are released in response to a variety of noxious stimuli (e.g. burns, sepsis, or CABG surgery). These cytokines cause activation of neutrophils with increased upregulation of adhesion complexes on neutrophils and vascular endothelium. Nitric oxide synthase activity is also increased with a resultant increased production of nitric oxide. The increased nitric oxide concentration in the presence of superoxide free radicals secreted by activated neutrophils forms peroxynitrite, a more reactive and toxic molecule. Once this process is initiated, diffuse organ injury can result. Although some information related to specific anaesthetics is available, firm recommendations related to clinical practice cannot be made.

CONCLUSIONS

There is a complex interplay of inflammatory mediators that can cause injury. Although specific clinical applications for manipulating these pathways are not yet generally available, this area holds promise to develop new techniques to improve outcomes following surgery.

Evaluation of various cytokines (IL-6, IFN-alpha, IFN-gamma, TNF-alpha) as markers for acute bacterial infection in swine--a possible role for serum interleukin-6

A total of 64 specific pathogen free pigs were divided into eight experimental groups. Pigs in Group I served as non-infected controls while the other 56 pigs were infected intranasally with approximately 7 x 10(8) CFU of Actinobacillus pleuropneumoniae serotype 2 (strain 700/89) in 1 ml saline. When more than 25% of the infected animals showed clinical signs of disease, i.e. 20 h post infection, 48 of the infected pigs were treated with different antibiotics (8 pigs per group), leaving 8 infected animals untreated. Serum samples collected 0, 10, 20, 28 and 44 h, and 3, 4, 7, 13 and 17 days post infection were analysed for their content of interferon (IFN)-alpha, IFN-gamma, tumor necrosis factor (TNF)-alpha by immunoassays and interleukin-6 (IL-6) by a bioassay. In addition, the development of specific antibodies was determined in sera. Among the cytokines analysed, the experimental infection only induced detectable serum levels of IL-6. The appearance of IL-6 positive animals coincided with the onset of clinical signs of disease and increased body temperatures. Varying levels of IL-6 (range, 1-220 U ml-1) were detected in serum from a majority of the infected pigs (80%). In general, the highest levels of IL-6 were detected in serum collected for 10 or 20 h after infection. Among the animals not treated with antibiotics, the number of pigs displaying IL-6 in serum continued to increase until 28 h post infection and then declined. The duration of the IL-6 response varied between individuals and lasted from eight hours to three days. Treatment with antibiotics that ceased the infection also terminated the IL-6 production in most of the pigs. In a pilot field survey, IL-6 was detected in an approximately 30% of serum samples collected from conventional reared pigs before allocation to finishing units. Thus, serum IL-6 seems to be a potential marker for ongoing bacterial infections in swine.

Interleukin-6 and stress hormone responses after uncomplicated gasless laparoscopic-assisted and open sigmoid colectomy

PURPOSE

Laparoscopic colectomy has increasingly been advocated as an option for treatment of colonic disease. The purpose of this study was to compare effects of laparoscopic-assisted sigmoid colectomy (LAS) and conventional open colectomy (OPEN) on postoperative cytokine and stress hormone responses.

METHODS

Fourteen patients with sigmoid colon cancer, apparently free of preoperative complications, were analyzed. Patients in both groups underwent sigmoid colectomy with lymphadenectomy. LAS was performed by the gasless abdominal wall-lifting method. A 5 cm incision was placed at the beginning of the operation. Blood samples were taken preoperatively and postoperatively for measurement of interleukin-6, glucagon and C-reactive protein. Urinary catecholamine excretions were also determined postoperatively.

RESULTS

The two groups of patients were similar with respect to age (61 +/- 7 for LAS vs. 64 +/- 9 for OPEN) and sex. Intraoperative blood loss did not differ significantly between groups (112 +/- 97 ml for LAS vs. 366 +/- 380 ml for OPEN). Operative times for LAS tended to be longer than those for OPEN (231 +/- 67 vs. 169 +/- 45 minutes; P = 0.08). Similar time courses of postoperative interleukin-6, C-reactive protein, and stress hormone responses were observed in both groups. No significant differences were observed in the magnitude of changes except that the serum interleukin-6 level on day of surgery (postoperative day 0) was significantly higher in LAS patients than in those receiving OPEN. In addition, interleukin-6 levels showed a significant positive correlation with operative duration (r = 0.582; P < 0.05).

CONCLUSIONS

Data suggest that stress responses after sigmoid colectomy, in patients undergoing LAS, are comparable with those of patients receiving OPEN and that the early interleukin-6 response after surgery appears to be associated with operative time.

Acute phase is the only significantly reduced component of the injury response after laparoscopic cholecystectomy

The objective demonstration of improved postoperative recovery suggests that the surgical injury response induced by the laparoscopic approach is less intensive than that after open surgery. Twenty-five patients diagnosed as having noncomplicated gallstones were studied prospectively. They were operated by laparoscopy (group I, n = 12) or open surgery (group II, n = 13). Analgesia requirements (p < 0.026) and postoperative stay (p < 0.001) were significantly less in group 1. Cholecystectomy performed by either technical options induced a significant increase over basal values of glucose, lactate, white blood cell count, prolactin, ACTH, cortisol, interleukin 6, C-reactive protein, and PCO2. Both surgical procedures induced a significant reduction of total proteins, albumin, prealbumin, free fatty acids hemoglobin, hematocrit, and pH. There were no differences between the levels of growth hormone, insulin, glucagon, or PO2 during any of the periods studied. Comparison of the results of the two cholecystectomy techniques showed that laparoscopic cholecystectomy induced a significantly less intensive acute-phase response (area under the curve) of interleukin 6 (17 +/- 17 versus 47 +/- 26 pg/ml x hr x 10(2); p < 0.003), C-reactive protein (16 +/- 12 versus 35 +/-16 mg/dl x hr x 10; p < 0.004), and prealbumin (16 +/- 2.7 versus 13.8 +/- 2.3 mg/dl x hr x 10(2); p < 0.05). The surgical injury response after laparoscopic cholecystectomy is similar to that after open cholecystectomy, but the aeute-phase response component is less intense. This finding may be a consequence of the reduced size of the operative wound with laparoscopic cholecystectomy.

Elevation of plasma interleukin-6 level in patients undergoing oral and maxillofacial surgery

OBJECTIVE

The purpose of this study was to evaluate the response of peripheral interleukin-6 associated with oral and maxillofacial surgery.

STUDY DESIGN

Fifteen patients undergoing elective oral and maxillofacial surgery were studied. We investigated the change in plasma interleukin-6 level during and after surgery and the correlation between plasma interleukin-6 level and surgical procedure. Plasma interleukin-6 levels were measured by enzyme-linked immunosorbent assay. Statistical significance was determined by nonparametric methods.

RESULTS

Elevation of plasma interleukin-6 level was detected at 2 to 6 hours after incision and observed to reach a peak level within 6 hours after the end of surgery. There were significant correlations between plasma interleukin-6 level and duration of surgery or response of C-reactive protein.

CONCLUSION

The results suggested that interleukin-6 would be released by surgical injury and elevation of plasma interleukin-6 level would be associated with magnitude of tissue damage in oral and maxillofacial surgery.

Toward a theory regarding the pathogenesis of the systemic inflammatory response syndrome: what we do and do not know about cytokine regulation

OBJECTIVES

The systemic inflammatory response syndrome (SIRS) is the massive inflammatory reaction resulting from systemic mediator release that may lead to multiple organ dysfunction. The objective of this review article is to analyze the roles of cytokines, cytokine production, and the relationship of cytokine production to the development of SIRS.

DATA SOURCES

Previous research and clinical studies related to cytokines and their relationship to SIRS.

STUDY SELECTION

From the studies reviewed, three critical questions are addressed. First, what is the definition of increased cytokine concentrations? Second, what other systemic illnesses besides sepsis can alter cytokine concentrations? Third, what are the right cytokines to measure?

DATA SYNTHESIS

This article postulates a three-stage development of SIRS, in which stage 1 is a local production of cytokines in response to an injury or infection. Stage 2 is the protective release of a small amount of cytokines into the body's circulation. Stage 3 is the massive systemic reaction where cytokines turn destructive by compromising the integrity of the capillary walls and flooding end organs.

CONCLUSIONS

While cytokines are generally viewed as a destructive development in the patient that generally leads to multiple organ dysfunction, cytokines also protect the body when localized. It will be necessary to study the positive effects of cytokines while also studying their role in causing SIRS. It will also be important to investigate the relationship between cytokines and their blockers in SIRS.

Leukocyte activation by isolated hyperthermic liver and limb perfusion due to malignancy

Fourteen patients with liver tumor malignancy and sixteen patients with malignant melanoma localized to one limb were studied regarding leukocyte activation with the release of polymorphonuclear neutrophilic (PMN) elastase and of neopterin and formation of cytokines (TNF-alpha and IL-6) during the surgical treatment. Patients undergoing liver resection (n = 10), abdominal hysterectomy (n = 10), or hip replacement surgery (n = 10) served as control groups. Isolated hyperthermic liver perfusion was performed with cytostatic-containing perfusate (melphalan and cisplatinum). Patients with recurrent malignant melanoma confined to one limb underwent isolated hyperthermic limb perfusion with cytostatic-containing perfusate (melphalan). Blood samples for determination of PMN elastase, neopterin, TNF-alpha, and IL-6 were drawn from the patients preoperatively, 1 minute before the start of the perfusion, 60 and 120 minutes after the start of the perfusion, and 24 hours postoperatively. Samples from the perfusate were drawn 60 minutes after the start of the perfusion. High concentration of plasma PMN elastase were found in both patients undergoing liver and limb perfusion and in patients undergoing liver resection surgery. Elevated concentrations of IL-6 were found in the patients undergoing liver perfusion and in patients undergoing liver resection. In none of the patients were there increased concentrations of neopterin or TNF-alpha. The perfusate contained high concentrations of PMN elastase, neopterin, and IL-6. This study also demonstrated that major surgery leads to elevated concentrations of PMN elastase and IL-6. An increase of PMN elastase and IL-6 was seen in response to perfusion and to surgical trauma.

New aspects concerning the regulation of the post-operative acute phase reaction during cardiac surgery

During a cardio-pulmonary bypass, as well as post-operatively, high levels of endotoxin, interleukin-6 (Il-6) and C-reactive protein (CRP) were measured in 30 patients. A significant increase in endotoxin plasma level occurred during surgery, culminating in a peak during reperfusion. Plasma levels of endotoxin continued to be slightly raised until the fifth day after surgery, whereas those of Il-6 rose at the time the operation came to an end and were at their highest 6 h later. CRP levels were also high, post-operatively, and were markedly raised on day 2. A definite, statistically significant correlation between the plasma levels of endotoxin and Il-6 during the operation was established, leading us to conclude that the endotoxin liberated during cardiac surgery acts as the main trigger in the release of Il-6 and thus induces the post-operative acute phase reaction. There was no evidence of a correlation between CRP and endotoxin or Il-6 plasma levels.