Effects of anaesthesia based on high versus low doses of opioids on the cytokine and acute-phase protein responses in patients undergoing cardiac surgery

Thoracic Epidural Anesthesia in Cardiac Surgery: A Systematic Review, Meta-Analysis, and Trial Sequential Analysis of Randomized Controlled Trials

BACKGROUND

Research on fast-track recovery protocols postulates that thoracic epidural anesthesia (TEA) in cardiac surgery contributes to improved postoperative outcomes. However, concerns about TEA's safety hinder its widespread usage. We conducted a systematic review and meta-analysis to assess the benefits and risks of TEA in cardiac surgery.

METHODS

We searched 4 databases for randomized controlled trials (RCTs) assessing the use of TEA against only general anesthesia (GA) in adults undergoing cardiac surgery, up till June 4, 2022. We conducted random-effects meta-analyses, evaluated risk of bias using the Cochrane Risk-of-Bias 2 tool, and rated certainty of evidence via the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. Primary outcomes were intensive care unit (ICU), hospital length of stay, extubation time (ET), and mortality. Other outcomes included postoperative complications. Trial sequential analysis (TSA) was conducted on all outcomes to elicit statistical and clinical benefit.

RESULTS

Our meta-analysis included 51 RCTs (2112 TEA patients and 2220 GA patients). TEA significantly reduced ICU length of stay (-6.9 hours; 95% confidence interval [CI], -12.5 to -1.2; P = .018), hospital length of stay (-0.8 days; 95% CI, -1.1 to -0.4; P < .0001), and ET (-2.9 hours; 95% CI, -3.7 to -2.0; P < .0001). However, we found no significant change in mortality. TSA found that the cumulative Z-curve passed the TSA-adjusted boundary for ICU length of stay, hospital length of stay, and ET, suggesting a clinical benefit. TEA also significantly reduced pain scores, pooled pulmonary complications, transfusion requirements, delirium, and arrhythmia, without additional complications such as epidural hematomas, of which the risk was estimated to be <0.14%.

CONCLUSIONS

TEA reduces ICU and hospital length of stay, and postoperative complications in patients undergoing cardiac surgery with minimal reported complications such as epidural hematomas. These findings favor the use of TEA in cardiac surgery and warrant consideration for use in cardiac surgeries worldwide.

Characterizing Alterations in Cortisol Secretion During Cardiac Surgery

Cortisol is a neuroendocrine hormone of the hypothalamus-pituitary-adrenal (HPA) axis secreted from adrenal glands in response to stimulation by adrenocorticotropic hormone (ACTH) from the anterior pituitary and corticotropin releasing hormone (CRH) from the hypothalamus. Cortisol has multiple functionalities in maintaining bodily homeostasis - including anti-inflammatory influences - through its diurnal secretion pattern (which has been studied extensively); its secretion is also increased in response to major traumatic events such as surgery. Due to the adverse health consequences of an abnormal immune response, it is crucial to understand the effect of cortisol in modulating inflammation. To address this physiological issue, we characterize the secretion of cortisol using a high temporal resolution dataset of ten patients undergoing coronary arterial bypass grafting (CABG) surgery, in comparison with a control group not undergoing surgery. We find that cortisol exhibits different pulsatile dynamics in those undergoing cardiac surgery compared to the control subjects. We also summarize the causality of cortisol's relationship with different cytokines (which are one type of inflammatory markers) by performing Granger causality analysis.Clinical relevance- This work documents time-varying patterns of the HPA axis hormone cortisol in the inflammatory response to cardiac surgery and may eventually help improve patients' prognosis post-surgery (or in other conditions) by enabling early detection of an abnormal cortisol or inflammatory response and enabling patient specific remedial interventions.

Sparse Deconvolution and Causality Analysis of Inflammatory Markers During Cardiac Surgery

Major bodily trauma such as cardiac surgery elicits (in response to tissue injury and other exogenous surgical factors) a whole-body inflammation response during which specialized signaling proteins called cytokines are synthesized and invoke multiple defense mechanisms. Many proinflammatory and anti-inflammatory cytokines such as interleukins (IL) and tumor necrosis factor (TNF) are produced to initiate bodily repair. Due to the adverse health consequences, including mortality, of a maladaptive cytokine response, understanding their complex dynamics using system-theoretic modeling and analysis may pave the way for controlling the inflammatory response which may eventually improve medical outcomes for patients. To this end, we use clinical data from ten patients undergoing coronary arterial bypass graft surgery to study the response of four cytokines (IL6, IL8, IL10, TNFα) and the neuroendocrine hormone cortisol. We perform deconvolution to obtain the secretory pulses underlying their pulsatile production and analyze causal interactions, mathematically uncovering some interactive relationships found in previous experimental studies.Clinical relevance- This work is a first step towards a mechanistic inference of the inflammatory response to surgery that could eventually help control the inflammatory response and could inform medical interventions to improve patient outcomes.

Comparison of regional anesthetic techniques for postoperative analgesia after adult cardiac surgery: bayesian network meta-analysis

Background

Patients usually suffer acute pain after cardiac surgery. Numerous regional anesthetic techniques have been used for those patients under general anesthesia. The most effective regional anesthetic technique was still unclear.

Methods

Five databases were searched, including PubMed, MEDLINE, Embase, ClinicalTrials.gov, and Cochrane Library. The efficiency outcomes were pain scores, cumulative morphine consumption, and the need for rescue analgesia in this Bayesian analysis. Postoperative nausea, vomiting and pruritus were safety outcomes. Functional outcomes included the time to tracheal extubation, ICU stay, hospital stay, and mortality.

Results

This meta-analysis included 65 randomized controlled trials involving 5,013 patients. Eight regional anesthetic techniques were involved, including thoracic epidural analgesia (TEA), erector spinae plane block, and transversus thoracic muscle plane block. Compared to controls (who have not received regional anesthetic techniques), TEA reduced the pain scores at 6, 12, 24 and 48 h both at rest and cough, decreased the rate of need for rescue analgesia (OR = 0.10, 95% CI: 0.016-0.55), shortened the time to tracheal extubation (MD = -181.55, 95% CI: -243.05 to -121.33) and the duration of hospital stay (MD = -0.73, 95% CI: -1.22 to -0.24). Erector spinae plane block reduced the pain score 6 h at rest and the risk of pruritus, shortened the duration of ICU stay compared to controls. Transversus thoracic muscle plane block reduced the pain scores 6 and 12 h at rest compared to controls. The cumulative morphine consumption of each technique was similar at 24, 48 h. Other outcomes were also similar among these regional anesthetic techniques.

Conclusions

TEA seems the most effective regional postoperative anesthesia for patients after cardiac surgery by reducing the pain scores and decreasing the rate of need for rescue analgesia.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, ID: CRD42021276645.

A comparison of opioid-containing anesthesia versus opioid-free anesthesia using the Cortínez-Sepúlveda model on differential cytokine responses in obese patients undergoing gastric bypass surgery: a randomized controlled trial

Background

Opioid anesthetic agents can modulate the impaired immune response in obese patients through mechanisms that involve the expression and release of cytokines. For this reason, anesthetic care for obese patients remains controversial. Therefore, the aim of the study was to compare the effect of opioid-containing anesthesia (OCA) vs opioid-free anesthesia (OFA) using the Cortínez-Sepúlveda model on IL-6, IL-1β and TNF-α serum levels before and after surgery in obese patients undergoing bypass surgery.

Methods

This randomized cross-sectional study conducted among 40 unrelated obese adults was performed in the Civil Hospital of Guadalajara “Dr. Juan I. Menchaca”. Before undergoing laparoscopic Roux-en-Y gastric bypass, patients were randomly assigned to two anesthesia groups: OCA (n = 20) or OFA (n = 20). Fentanyl was the opioid used in the OCA group. The Cortínez-Sepúlveda pharmacokinetic model was used to characterize the disposition of intravenous propofol for the target-controlled infusion technique in obese patients. Body mass was determined to the nearest 0.05 kg using a balance scale (Seca 703; Seca, Hamburg, Germany). Blood samples were taken before and immediately after surgery and cytokine concentrations were determined by ELISA. Pain was assessed using a numerical pain rating scale. Adverse effects were collected within the first 24 h after surgery.

Results

A total of 6 men and 34 women were included (37.9 ± 10.6 years). Pre-surgery IL-6 and TNF-α serum levels were not detected in study subjects. However, IL-1β levels significantly decreased after surgery (49.58 pg/mL (18.50–112.20)-before surgery vs 13 pg/mL (5.43–22)-after surgery, p = 0.019). IL-6 concentrations were significantly higher in subjects who received OCA (with fentanyl) compared to subjects with OFA (224.5 pg/mL (186.3–262.8) vs 99.5 pg/mL (60.8–138.2), respectively, p < 0.001; adjusted by age, gender, and BMI). In addition, the use of opioids confers an increased risk for higher IL-6 levels in obese patients (OR = 2.95, 95% CI: 1.2–7.2, p = 0.010). A linear regression model showed that the operative time (in hours) of bypass surgery and anesthetic technique were positively correlated with IL-6 levels.

Conclusion

Anesthesia with opioids correlated positively with IL-6 serum levels in obese patients undergoing bypass surgery. This finding could have clinical relevance when an appropriate anesthetic management plan is selected for bariatric surgical patients.

Trial registration

The study was retrospectively registered at ClinicalTrials.gov Identification Number: NCT04854252, date 22/04/2021.

Effects of Depth of Anesthesia Monitored by IoC on Patients Undergoing Laparoscopic Radical Resection of Colorectal Cancer

Index of consciousness (IoC) consisting of IoC1 and IoC2, is a new analgesia monitoring indicator in anesthesia evaluation in the laparoscopic radical resection of colorectal cancer. Although the precise anesthetic dosage adjusted by IoC1 has been confirmed to enhance the recovery and reduce the complications of anesthesia, the most appropriate range of IoC2 during anesthesia remains unclear. To investigate the correlation between IoC2 and peri-operative indicators of patients during laparoscopic radical resection of colorectal cancer, the current randomized, controlled, and single-blinded clinical trial was performed. Participants were divided randomly into three groups with different anesthesia depth monitored by IoC2 during their laparoscopic radical resections. Primary outcomes included the dosage of remifentanil. Secondary outcomes included other physiological indexes and complications. The remifentanil dosage and the awakening time increased as IoC2 decreased. The incidences of hypotension and hypoxemia decreased with the elevated IoC2, but the risk of intra-operative awareness also increased. The impact caused by anesthesia to the immune system and health-related life quality of the patients descended with reduced anesthetic level. The IoC2 range of 35–45 could represent the most appropriate anesthetic depth during laparoscopic radical resection, which provides a new perspective for the clinical treatment of colon cancer.

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.

The effect of anesthesia on the postoperative systemic inflammatory response in patients undergoing surgery: A systematic review and meta-analysis

BACKGROUND

Surgical injury stimulates the systemic inflammatory response. The magnitude of the postoperative systemic inflammatory response has been shown to be significantly associated with short and long-term outcomes following surgery of varying severity. Different anesthetic techniques for surgery may have an impact on the postoperative systemic inflammatory response and on the rate of the postoperative infective complications.The aim of the present systematic review was to examine the relationship between perioperative anesthesia, the postoperative systemic inflammatory response and postoperative infective complications in patients undergoing surgery.

METHODS

This was carried out using PubMed and other established databases from 1987 up to March 2018. In particular, randomized controlled studies and systemic inflammation markers, interleukin 6 and C-reactive protein were examined.

RESULTS

Overall, 60 controlled, randomized clinical trials were included in the review. The mean or median values of both interleukin 6 and C-reactive protein were taken for each study and the mean value was calculated for each anesthetic group at sampling points of 12-24 and 24-72 hours for interleukin 6 and C-reactive protein respectively. When taking the magnitude of surgery into account, TIVA using propofol was significantly associated with a reduction in particular C-reactive protein (P = .04). However, there were no other specific anesthetic methods including general, regional and combined anesthetics that were associated with a reduction in either interleukin 6 or C-reactive protein.

CONCLUSION

There is some evidence that anesthetic regimens may reduce the magnitude of the postoperative systemic inflammatory response. However, the studies were heterogeneous and generally of low quality.Future, well conducted, adequately powered studies are required to clarify the effect of anesthesia on the postoperative systemic inflammatory response and infective complications.

Biomarkers for Evaluating the Inflammation Status in Patients with Cancer

Inflammation can be a causative factor for carcinogenesis or can result from a consequence of cancer progression. Moreover, cancer therapeutic interventions can also induce an inflammatory response. Various inflammatory parameters are used to assess the inflammatory status during cancer treatment. It is important to select the most optimal biomarker among these parameters. Additionally, suitable biomarkers must be examined if there are no known parameters. We briefly reviewed the published literature for the use of inflammatory parameters in the treatment of patients with cancer. Most studies on inflammation evaluated the correlation between host characteristics, effect of interventions, and clinical outcomes. Additionally, the levels of C-reactive protein, albumin, lymphocytes, and platelets were the most commonly used laboratory parameters, either independently or in combination with other laboratory parameters and clinical characteristics. Furthermore, the immune parameters are classically examined using flow cytometry, immunohistochemical staining, and enzyme-linked immunosorbent assay techniques. However, gene expression profiling can aid in assessing the overall peri-interventional immune status. The checklists of guidelines, such as STAndards for Reporting of Diagnostic accuracy and REporting recommendations for tumor MARKer prognostic studies should be considered when designing studies to investigate the inflammatory parameters. Finally, the data should be interpreted after adjusting for clinically important variables, such as age and cancer stage.

DEXAMETHASONE - INTRATHECAL MINIMISER OF SIMPLE HAEMATHOLOGIC STRESS BIOMARKERS IN HIP FRACTURE

Proximal femoral fractures are the most common cause of emergency admission to hospital with high postoperative morbidity. The hypothesis was that a single shot of intrathecal dexamethasone and levobupivacaine in anaesthesia for surgical correction of proximal femoral fracture in elderly patients reduces surgical stress with better quality hospitalisation. The study included sixty elderly patients with proximal femoral fracture, ASA status 2 and 3, randomised into two groups. The study group of thirty patients received 8 mg of dexamethasone and 12,5 mg of levobupivacaine 0,5% intrathecally, DLSA group, and the parallel group of thirty patients received 12,5 mg of levobupivacaine 0,5% intrathecally, LSA group. Plasma cortisol and glucose concentrations were assessed before and after anaesthesia, pain intensity was evaluated using Visual Analogue Scale score and hospitalisation was analysed. Results showed decreased cortisol concentrations, longer analgesia duration and shorter hospitalisation in the DLSA group. Glucose concentrations did not differ significantly between the patients in either group. Enlightening the study results collected, single shot of intrathecal administration of dexamethasone in spinal anaesthesia for surgical treatment of proximal femoral fractures reduces the stress response by decreasing plasma cortisol concentrations prolonging analgesia with better rehabilitation possibilities, hence shortening hospitalisation which explains this pattern of anaesthesia.

Epidural analgesia for adults undergoing cardiac surgery with or without cardiopulmonary bypass

BACKGROUND

General anaesthesia combined with epidural analgesia may have a beneficial effect on clinical outcomes. However, use of epidural analgesia for cardiac surgery is controversial due to a theoretical increased risk of epidural haematoma associated with systemic heparinization. This review was published in 2013, and it was updated in 2019.

OBJECTIVES

To determine the impact of perioperative epidural analgesia in adults undergoing cardiac surgery, with or without cardiopulmonary bypass, on perioperative mortality and cardiac, pulmonary, or neurological morbidity.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase in November 2018, and two trial registers up to February 2019, together with references and relevant conference abstracts.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) including adults undergoing any type of cardiac surgery under general anaesthesia and comparing epidural analgesia versus another modality of postoperative pain treatment. The primary outcome was mortality.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

We included 69 trials with 4860 participants: 2404 given epidural analgesia and 2456 receiving comparators (systemic analgesia, peripheral nerve block, intrapleural analgesia, or wound infiltration). The mean (or median) age of participants varied between 43.5 years and 74.6 years. Surgeries performed were coronary artery bypass grafting or valvular procedures and surgeries for congenital heart disease. We judged that no trials were at low risk of bias for all domains, and that all trials were at unclear/high risk of bias for blinding of participants and personnel taking care of study participants.Epidural analgesia versus systemic analgesiaTrials show there may be no difference in mortality at 0 to 30 days (risk difference (RD) 0.00, 95% confidence interval (CI) -0.01 to 0.01; 38 trials with 3418 participants; low-quality evidence), and there may be a reduction in myocardial infarction at 0 to 30 days (RD -0.01, 95% CI -0.02 to 0.00; 26 trials with 2713 participants; low-quality evidence). Epidural analgesia may reduce the risk of 0 to 30 days respiratory depression (RD -0.03, 95% CI -0.05 to -0.01; 21 trials with 1736 participants; low-quality evidence). There is probably little or no difference in risk of pneumonia at 0 to 30 days (RD -0.03, 95% CI -0.07 to 0.01; 10 trials with 1107 participants; moderate-quality evidence), and epidural analgesia probably reduces the risk of atrial fibrillation or atrial flutter at 0 to 2 weeks (RD -0.06, 95% CI -0.10 to -0.01; 18 trials with 2431 participants; moderate-quality evidence). There may be no difference in cerebrovascular accidents at 0 to 30 days (RD -0.00, 95% CI -0.01 to 0.01; 18 trials with 2232 participants; very low-quality evidence), and none of the included trials reported any epidural haematoma events at 0 to 30 days (53 trials with 3982 participants; low-quality evidence). Epidural analgesia probably reduces the duration of tracheal intubation by the equivalent of 2.4 hours (standardized mean difference (SMD) -0.78, 95% CI -1.01 to -0.55; 40 trials with 3353 participants; moderate-quality evidence). Epidural analgesia reduces pain at rest and on movement up to 72 hours after surgery. At six to eight hours, researchers noted a reduction in pain, equivalent to a reduction of 1 point on a 0 to 10 pain scale (SMD -1.35, 95% CI -1.98 to -0.72; 10 trials with 502 participants; moderate-quality evidence). Epidural analgesia may increase risk of hypotension (RD 0.21, 95% CI 0.09 to 0.33; 17 trials with 870 participants; low-quality evidence) but may make little or no difference in the need for infusion of inotropics or vasopressors (RD 0.00, 95% CI -0.06 to 0.07; 23 trials with 1821 participants; low-quality evidence).Epidural analgesia versus other comparatorsFewer studies compared epidural analgesia versus peripheral nerve blocks (four studies), intrapleural analgesia (one study), and wound infiltration (one study). Investigators provided no data for pulmonary complications, atrial fibrillation or flutter, or for any of the comparisons. When reported, other outcomes for these comparisons (mortality, myocardial infarction, neurological complications, duration of tracheal intubation, pain, and haemodynamic support) were uncertain due to the small numbers of trials and participants.

AUTHORS' CONCLUSIONS

Compared with systemic analgesia, epidural analgesia may reduce the risk of myocardial infarction, respiratory depression, and atrial fibrillation/atrial flutter, as well as the duration of tracheal intubation and pain, in adults undergoing cardiac surgery. There may be little or no difference in mortality, pneumonia, and epidural haematoma, and effects on cerebrovascular accident are uncertain. Evidence is insufficient to show the effects of epidural analgesia compared with peripheral nerve blocks, intrapleural analgesia, or wound infiltration.

Regional Anesthesia in Cardiac Surgery: A Friend or A Foe?

Escalating costs and change in the profile of patients presenting for cardiac surgery requires modification of perioperative management strategies. Regional anesthesia has played an integral part of many fast-track anesthesia protocols across North America and Europe. This review suggests that for patients undergoing coronary artery bypass graft surgery, the risk-to-benefit ratio is in favor of epidural and spinal anesthesia, provided there are no specific contraindications and the guidelines for the use of regional techniques in cardiac surgery are followed. Patients managed with regional techniques seem to benefit from superior postoperative analgesia, shorter postoperative ventilation, reduced incidence of supraventricular arrhythmia, and lower rates of perioperative myocardial infarction. The results of this analysis suggest that for each episode of neurologic complication, 20 myocardial infarctions and 76 episodes of atrial fibrillation would be prevented, thus, we would consider the regional anesthesia and analgesia to be an effective strategy that improves perioperative morbidity. However, other treatment modalities such as the addition of calcium channel blockers, aspirin, and beating heart surgery, are also suggested to be beneficial in cardiac surgical patients and may impose less risk than the use of regional techniques. We believe that the results presented in this review are encouraging enough to permit continued investigation. A prospective, randomized, controlled multicenter trial needs to be adequately powered to answer important clinical questions and allow for a long-term follow-up.

Pulmonary complications of cardiopulmonary bypass

Pulmonary complications after the use of extracorporeal circulation are common, and they range from transient hypoxemia with altered gas exchange to acute respiratory distress syndrome (ARDS), with variable severity. Similar to other end-organ dysfunction after cardiac surgery with extracorporeal circulation, pulmonary complications are attributed to the inflammatory response, ischemia-reperfusion injury, and reactive oxygen species liberated as a result of cardiopulmonary bypass. Several factors common in cardiac surgery with extracorporeal circulation may worsen the risk of pulmonary complications including atelectasis, transfusion requirement, older age, heart failure, emergency surgery, and prolonged duration of bypass. There is no magic bullet to prevent or treat pulmonary complications, but supportive care with protective ventilation is important. Targets for the prevention of pulmonary complications include mechanical, surgical, and anesthetic interventions that aim to reduce the contact activation, systemic inflammatory response, leukocyte sequestration, and hemodilution associated with extracorporeal circulation.

The tryptophan kynurenine pathway, neopterin and IL-6 during vulvectomy and abdominal hysterectomy

Background

Surgery has wide ranging immunomodulatory properties of which the mechanism is poorly understood. In order to investigate how different types of surgery influence inflammation, we designed a longitudinal observational study investigating two inflammatory profiles of two separate patient groups undergoing gynaecological operations of differing severity. In addition to measuring the well known inflammatory markers neopterin and IL-6, we also determined the kynurenine/tryptophan ratio.

This study was a prospective, single center, two-armed observational study involving 28 female patients. Plasma levels of tryptophan, kynurenine, neopterin and IL-6 were determined from samples taken at: 24hrs pre-operative, prior to induction, ten minutes before the operation was expected to end, and at 24 and 96 hours post operative in patients undergoing abdominal hysterectomy and vulvectomy.

Results

There were 15 and 13 patients included in the vulvectomy and abdominal hysterectomy groups, respectively. In this study we show that anesthesia and surgery significantly increases the enzyme activity of indoleamine 2, 3 dioxygenase (IDO) as measured by the kynurenine/tryptophan ratio (P=0.003), while maintaining stable neopterin levels. However, abdominal hysterectomy causes a considerable IL-6 increase (P<0.001).

Conclusion

Surgery and associated anesthesia cause a significant tryptophan level decrease while significantly increasing IDO activity. Both types of surgery produce nearly identical neopterin time curve relationships, with no significant change occurring in either group. However, even though neopterin is unaffected by the severity of surgery, IL-6 responded to surgical invasiveness by revealing a significant increase during abdominal hysterectomy.

Epidural analgesia for cardiac surgery

BACKGROUND

A combination of general anaesthesia (GA) with thoracic epidural analgesia (TEA) may have a beneficial effect on clinical outcomes by reducing the risk of perioperative complications after cardiac surgery.

OBJECTIVES

The objective of this review was to determine the impact of perioperative epidural analgesia in cardiac surgery on perioperative mortality and cardiac, pulmonary or neurological morbidity. We performed a meta-analysis to compare the risk of adverse events and mortality in patients undergoing cardiac surgery under general anaesthesia with and without epidural analgesia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 12) in The Cochrane Library; MEDLINE (PubMed) (1966 to November 2012); EMBASE (1989 to November 2012); CINHAL (1982 to November 2012) and the Science Citation Index (1988 to November 2012).

SELECTION CRITERIA

We included randomized controlled trials comparing outcomes in adult patients undergoing cardiac surgery with either GA alone or GA in combination with TEA.

DATA COLLECTION AND ANALYSIS

All publications found during the search were manually and independently reviewed by the two authors. We identified 5035 titles, of which 4990 studies did not satisfy the selection criteria or were duplicate publications, that were retrieved from the five different databases. We performed a full review on 45 studies, of which 31 publications met all inclusion criteria. These 31 publications reported on a total of 3047 patients, 1578 patients with GA and 1469 patients with GA plus TEA.

MAIN RESULTS

Through our search (November 2012) we have identified 5035 titles, of which 31 publications met our inclusion criteria and reported on a total of 3047 patients. Compared with GA alone, the pooled risk ratio (RR) for patients receiving GA with TEA showed an odds ratio (OR) of 0.84 (95% CI 0.33 to 2.13, 31 studies) for mortality; 0.76 (95% CI 0.49 to 1.19, 17 studies) for myocardial infarction; and 0.50 (95% CI 0.21 to 1.18, 10 studies) for stroke. The relative risks (RR) for respiratory complications and supraventricular arrhythmias were 0.68 (95% CI 0.54 to 0.86, 14 studies) and 0.65 (95% CI 0.50 to 0.86, 15 studies) respectively.

AUTHORS' CONCLUSIONS

This meta-analysis of studies, identified to 2010, showed that the use of TEA in patients undergoing coronary artery bypass graft surgery may reduce the risk of postoperative supraventricular arrhythmias and respiratory complications. There were no effects of TEA with GA on the risk of mortality, myocardial infarction or neurological complications compared with GA alone.

The effect of robenacoxib on the concentration of C-reactive protein in synovial fluid from dogs with osteoarthritis

Background

Robenacoxib is a novel and highly selective inhibitor of COX-2 in dogs and cats and because of its acidic nature is regarded as being tissue-selective. Thirty four dogs with stifle osteoarthritis secondary to failure of the cranial cruciate ligament were recruited into this study. Lameness, radiographic features, synovial cytology and C-reactive protein concentrations in serum and synovial fluid were assessed before and 28 days after commencing a course of Robenacoxib at a dose of 1 mg/kg SID.

Results

There was a significant reduction in the lameness score (P < 0.01) and an increase in the radiographic score (P < 0.05) between pre- and post-treatment assessments. There was no difference between pre- (median 1.49 mg/l; Q1-Q3 0.56-4.24 mg/L) and post – (1.10 mg/L; 0.31-1.78 mg/L) treatment serum C-reactive protein levels although synovial fluid levels were significantly reduced (pre- : 0.44 mg/L; 0.23-1.62 mg/L; post- : 0.17 mg/L; 0.05-0.49 mg/L) (P < 0.05). There was no correlation between C-reactive protein concentrations in serum and matched synovial fluid samples.

Conclusions

Robenacoxib proved effective in reducing lameness in dogs with failure of the cranial cruciate ligament and osteoarthritis of the stifle joint. The drug also reduced levels of C-reactive protein in the synovial fluid taken from the affected stifle joint. Robenacoxib appears to reduce articular inflammation as assessed by C-reactive protein which supports the concept that Robenacoxib is a tissue-selective non-steroidal anti-inflammatory drug.

Effects of spray-dried animal plasma on serous and intestinal redox status and cytokines of neonatal piglets

The study investigated the effects of dietary supplementation with spray-dried animal plasma (SDAP) on growth performance, intestinal morphology, as well as serum and intestinal cytokines and antioxidant indicators of artificially reared neonatal piglets. Three diets, 1) control (a fish meal basal diet), 2) SDAP (containing 10% SDAP), and 3) autoclaved SDAP (auSDAP; containing 10% auSDAP), were fed to 36 weaned piglets (3 d old), which were randomly allotted to 3 groups. At 21 d of age, blood and intestinal mucosal samples were collected from all piglets after they were slaughtered. Compared with the control, both SDAP and auSDAP improved ADFI and duodenal villus height of piglets (P < 0.05), whereas SDAP increased ADG and duodenal villus height to crypt depth ratio (P < 0.05). Piglets fed SDAP and auSDAP had reduced malondialdehyde (MDA) content in mucosa (P < 0.05). The concentration of serum MDA was decreased and mucosal catalase (CAT) activities were increased in piglets fed SDAP diet than those fed the control diet (P < 0.05). In the mucosa, both SDAP and auSDAP decreased tumor necrosis factor α, IL-6, transforming growth factor β, and soluble IL-2 receptor contents (P < 0.05). Mucosal IL-1β was decreased in SDAP compared with auSDAP and control groups (P < 0.05). The SDAP and control groups had increased mucosal IL-2 compared with auSDAP group (P < 0.05). The cytokines in serum were not affected by SDAP and auSDAP. The results indicate that both SDAP and auSDAP improved the growth performance of neonatal piglets, whereas the SDAP had a greater effect. The benefits of SDAP probably resulted from the promotion of the intestinal development, which were accompanied by the increased antioxidant capacity and the decreased production of inflammatory factors in the intestinal mucosa.

Epidural analgesia improves outcome in cardiac surgery: a meta-analysis of randomized controlled trials

OBJECTIVE

The authors conducted a review of randomized studies to determine whether there were any advantages for clinically relevant outcomes by adding epidural analgesia in patients undergoing cardiac surgery under general anesthesia.

DESIGN

Meta-analysis.

SETTING

Hospitals.

PARTICIPANTS

A total of 2366 patients from 33 randomized trials.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

DATA SOURCES AND STUDY SELECTION

PubMed, BioMedCentral, CENTRAL, EMBASE, Cochrane Central Register of Controlled Trials, and conference proceedings were searched (updated January 2008) for randomized trials that compared general anesthesia with an anesthetic plan including general anesthesia and epidural analgesia in cardiac surgery. Two independent reviewers appraised study quality, with divergences resolved by consensus. Overall analysis showed that epidural analgesia reduced the risk of the composite endpoint mortality and myocardial infarction (30/1125 [2.7%] in the epidural group v 64/1241 [5.2%] in the control arm, odds ratio [OR] = 0.61 [0.40-0.95], p = 0.03 number needed to treat [NNT] = 40), the risk of acute renal failure (35/590 [5.9%] in the epidural group v 54/618 [8.7%] in the control arm, OR = 0.56 [0.34-0.93], p = 0.02, NNT = 36), and the time of mechanical ventilation (weighted mean differences = -2.48 hours [-2.64, -2.32], p < 0.001).

CONCLUSIONS

This analysis suggested that epidural analgesia on top of general anesthesia reduced the incidence of perioperative acute renal failure, the time on mechanical ventilation, and the composite endpoint of mortality and myocardial infarction in patients undergoing cardiac surgery.

Assessment of cardiac troponin I and C-reactive protein concentrations associated with anesthetic protocols using sevoflurane or a combination of fentanyl, midazolam, and sevoflurane in dogs

OBJECTIVE

To report serum cardiac troponin I (cTnI) and C-reactive protein (CRP) concentrations in dogs anesthetized for elective surgery using two anesthetic protocols.

STUDY DESIGN

Prospective, randomized clinical study.

ANIMALS

Twenty client-owned dogs presenting for elective ovariohysterectomy or castration.

METHODS

The dogs were randomized into two groups. All dogs were premedicated with glycopyrrolate (0.011 mg kg(-1)) and hydromorphone (0.1 mg kg(-1)) i.m. approximately 30 minutes prior to induction of anesthesia. Anesthesia in dogs in group 1 was induced with propofol (6 mg kg(-1)) i.v. to effect and in dogs in group 2 with diazepam (0.2 mg kg(-1)) i.v. followed by etomidate (2 mg kg(-1)) i.v. to effect. For maintenance of anesthesia, group 1 received sevoflurane (adjustable vaporizer setting 0.5-4%) and group 2 received a combination of fentanyl (0.8 microg kg(-1) minute(-1)) and midazolam (8.0 microg kg(-1) minute(-1)) i.v. plus sevoflurane (adjustable vaporizer setting 0.5-4%) to maintain anesthesia. Serum cTnI and CRP concentrations were measured at baseline and 6, 18, and 24 hours post-anesthetic induction. Biochemical analysis was performed at baseline. Lactate was obtained at baseline and 6 hours post-anesthetic induction. Heart rate and mean arterial blood pressure were measured intra-operatively.

RESULTS

Baseline serum cTnI and CRP concentrations were comparable between groups. A significant difference in serum cTnI or CRP concentrations was not detected post-operatively between groups at any time point. Serum CRP concentrations were significantly increased post-anesthetic induction in both groups, which was attributed to surgical trauma.

CONCLUSIONS AND CLINICAL RELEVANCE

There was no significant difference in serum cTnI and CRP concentrations between anesthetic protocols. Further investigation in a larger number of dogs is necessary to confirm the current findings.

The effects of sevoflurane on systemic and pulmonary inflammatory responses after cardiopulmonary bypass

OBJECTIVE

During reperfusion after cardiopulmonary bypass, leukocytes are retained in the lungs. The purpose of this study was to examine the effect of sevoflurane on the inflammatory responses of the lungs after cardiopulmonary bypass.

DESIGN

A prospective, randomized clinical investigation.

SETTING

A university hospital.

PARTICIPANTS

Thirty patients undergoing valve replacement surgery using cardiopulmonary bypass.

INTERVENTIONS

Fifteen patients in whom anesthesia was maintained with sevoflurane and the priming solution was saturated with sevoflurane were randomly assigned to the sevoflurane group. Similarly, 15 patients in whom anesthesia was maintained with sufentanil and the priming solution was mixed with sufentanil were randomly assigned to the sufentanil group

MEASUREMENTS AND MAIN RESULTS

After induction, an arterial blood sample was obtained for the baseline leukocyte count. Blood was collected from the pulmonary artery (PA) and vein (PV) before cardiopulmonary bypass and 10 minutes after the restoration of heart beats. The leukocyte count, levels of interleukin-6, interleukin-8, interleukin-10, and tumor necrosis factor-alpha were measured. The PV/PA ratio of each parameter was determined for the assessment of inflammatory response of the lung. The leukocyte counts and plasma levels of cytokines increased more in the sufentanil group than the sevoflurane group. The PV/PA ratio of neutrophils decreased after the restoration of heart beats in the sufentanil group but was unchanged in the sevoflurane group. The PV/PA ratio of IL-6 was higher in the sufentanil group. The PV/PA ratio of interleukin-8 and interleukin-10 increased after the restoration of the pulmonary circulation in the sufentanil group but decreased in the sevoflurane group. The PV/PA ratio of tumor necrosis factor alpha increased in the sufentanil group but remained unchanged in the sevoflurane group.

CONCLUSIONS

Sevoflurane attenuates the pulmonary sequestration of neutrophil and leukocytes and also preserves the pulmonary consumption of cytokines at the time of early pulmonary reperfusion. Sevoflurane attenuates the systemic inflammatory response induced by cardiopulmonary bypass.

Heat stroke and cytokines

Heat stroke is a life-threatening illness that affects all segments of society, including the young, aged, sick, and healthy. The recent high death toll in France (Dorozynski, 2003) and the death of high-profile athletes has increased public awareness of the adverse effects of heat injury. However, the etiology of the long-term consequences of this syndrome remains poorly understood such that preventive/treatment strategies are needed to mitigate its debilitating effects. Cytokines are important modulators of the acute phase response (APR) to stress, infection, and inflammation. Current data implicating cytokines in heat stroke responses are mainly from correlation studies showing elevated plasma levels in heat stroke patients and experimental animal models. Correlation data fall far short of revealing the mechanisms of cytokine actions such that additional research to determine the role of these endogenous substances in the heat stroke syndrome is required. Furthermore, cytokine determinations have occurred mainly at end-stage heat stroke, such that the role of these substances in progression and long-term recovery is poorly understood. Despite several studies implicating cytokines in heat stroke pathophysiology, few studies have examined the protective effect(s) of cytokine antagonism on the morbidity and mortality of heat stroke. This is particularly surprising since heat stroke responses resemble those observed in the endotoxemic syndrome, for which a role for endogenous cytokines has been strongly implicated. The implication of cytokines as mediators of endotoxemia and the presence of circulating endotoxin in heat stroke patients suggests that much knowledge can be gained from applying our current understanding of endotoxemic pathophysiology to the study of heat stroke. Heat shock proteins (HSPs) are highly conserved proteins that function as molecular chaperones for denatured proteins and reciprocally modulate cytokine production in response to stressful stimuli. HSPs have been shown repeatedly to confer protection in heat stroke and injury models. Interactions between HSPs and cytokines have received considerable attention in the literature within the last decade such that a complex pathway of interactions between cytokines, HSPs, and endotoxin is thought to be occurring in vivo in the orchestration of the APR to heat injury. These data suggest that much of the pathophysiologic changes observed with heat stroke are not a consequence of heat exposure, per se, but are representative of interactions among these three (and presumably additional) components of the innate immune response. This chapter will provide an overview of current knowledge regarding cytokine, HSP, and endotoxin interactions in heat stroke pathophysiology. Insight is provided into the potential therapeutic benefit of cytokine neutralization for mitigation of heat stroke morbidity and mortality based on our current understanding of their role in this syndrome.

Inflammatory response and cardioprotection during open-heart surgery: the importance of anaesthetics

Open-heart surgery triggers an inflammatory response that is largely the result of surgical trauma, cardiopulmonary bypass, and organ reperfusion injury (e.g. heart). The heart sustains injury triggered by ischaemia and reperfusion and also as a result of the effects of systemic inflammatory mediators. In addition, the heart itself is a source of inflammatory mediators and reactive oxygen species that are likely to contribute to the impairment of cardiac pump function. Formulating strategies to protect the heart during open heart surgery by attenuating reperfusion injury and systemic inflammatory response is essential to reduce morbidity. Although many anaesthetic drugs have cardioprotective actions, the diversity of the proposed mechanisms for protection (e.g. attenuating Ca(2+) overload, anti-inflammatory and antioxidant effects, pre- and post-conditioning-like protection) may have contributed to the slow adoption of anaesthetics as cardioprotective agents during open heart surgery. Clinical trials have suggested at least some cardioprotective effects of volatile anaesthetics. Whether these benefits are relevant in terms of morbidity and mortality is unclear and needs further investigation. This review describes the main mediators of myocardial injury during open heart surgery, explores available evidence of anaesthetics induced cardioprotection and addresses the efforts made to translate bench work into clinical practice.

Comparison of the Modulatory Effects of Four Different Fast-Track Anesthetic Techniques on the Inflammatory Response to Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVES

To test the hypothesis that the choice of anesthesia technique for coronary artery surgery influences the degree and magnitude of the subsequent inflammatory response and its consequences.

DESIGN

Prospective, randomized, comparative study.

SETTING

Major university teaching hospital.

PARTICIPANTS

Sixty patients undergoing elective surgery.

INTERVENTIONS

Patients were randomized into an alfentanil group, a high-dose remifentanil group, a low-dose remifentanil group, or a thoracic epidural group, in combination with a propofol target-controlled infusion. The study was blinded for the opioid, except in the epidural group. Tight control of perioperative hemodynamic parameters was maintained, and the postoperative management was strictly standardized. Bactericidal permeability-increasing protein as an indicator of the polymorphonuclear neutrophil response, interleukin-6 as an inducer of the acute-phase response, and lipopolysaccharide-binding protein and C-reactive protein as parameters of the acute phase response were determined at regular intervals. Ventilator dependency and analgesia were evaluated as clinical outcome measures.

MEASUREMENTS AND MAIN RESULTS

Interleukin-6 levels increased in all groups. Plasma levels in the epidural group were significantly higher at all time points than in the other groups. The increase in the plasma levels of bactericidal permeability-increasing protein, lipopolysaccharide-binding protein, and C-reactive protein showed the same pattern in all groups, and no significant differences among the 4 groups were observed.

CONCLUSIONS

Supplementation of a fast-track anesthetic technique with epidural analgesia preserves hemodynamic stability and is associated with faster extubation times (p = 0.003) and less postoperative pain (p = 0.045). Thoracic epidural analgesia was associated with significantly higher levels of IL-6 throughout the study period as compared with the total intravenous anesthesia groups. The exact clinical relevance of this finding remains unclear.

Growth hormone prevents acute liver injury induced by cardiopulmonary bypass in a rat model

OBJECTIVE

Cardiopulmonary bypass-induced acute liver injury is a life-threatening complication thought to be associated with the inflammatory response and the acute-phase response. Recombinant human growth hormone can modulate the acute-phase response and inflammatory response. We tested the protective effect of growth hormone on cardiopulmonary bypass-induced liver injury in the rat.

METHODS

Adult male Sprague-Dawley rats (group G received 2.5 mg/kg recombinant human growth hormone intramuscularly at 8 am every 24 hours for 3 days and just before the initiation of cardiopulmonary bypass; group C served as a control group) underwent cardiopulmonary bypass (120 minutes, 120 mL x kg(-1) x min(-1), 34 degrees C) and were killed 3 hours after the termination of cardiopulmonary bypass.

RESULTS

Administration of recombinant human growth hormone markedly increased serum insulin-like growth factor and insulin-like growth factor-binding protein 3 levels compared with those seen in group C. Group G showed significantly lower serum concentrations of alanine aminotransferase and total bilirubin after cardiopulmonary bypass termination. Those receiving recombinant human growth hormone demonstrated a significant increase in serum prealbumin and transferrin levels and a marked decrease in serum amyloid A and C-reactive protein levels. Recombinant human growth hormone significantly decreased serum tumor necrosis factor alpha and interleukin 1beta levels, whereas no changes were found for serum interleukin 6 and interleukin 10 levels. Recombinant human growth hormone significantly increased total liver protein content and hepatocyte proliferation and decreased hepatocyte apoptosis versus values seen in group C.

CONCLUSIONS

These results suggest that growth hormone prevents cardiopulmonary bypass-induced acute liver injury in a rat model through decreases in acute-phase proteins, proinflammatory cytokines tumor necrosis factor alpha and interleukin 1beta, and hepatocyte apoptosis, which is associated with increases in constitutive hepatic proteins, total liver protein content, and hepatocyte proliferation. This strategy of pretreatment with growth hormone might be a prospective management for preventing acute liver injury when major cardiac surgery with cardiopulmonary bypass is performed.

The Effects of Morphine and Fentanyl on the Inflammatory Response to Cardiopulmonary Bypass in Patients Undergoing Elective Coronary Artery Bypass Graft Surgery

BACKGROUND

Experimental data suggest that morphine has unique antiinflammatory properties. We hypothesized that morphine, when compared with fentanyl, would attenuate the perioperative inflammatory response to cardiopulmonary bypass (CPB) when administered as part of a balanced anesthetic technique.

METHODS

Thirty patients undergoing elective coronary artery bypass graft surgery were randomized to receive, in a double-blind manner, either morphine (40 mg) or fentanyl (1000 microg) as part of a standardized opioid-isoflurane anesthetic. Serum concentrations of interleukin (IL)-6 and IL-8 and expression of neutrophil surface adhesion molecules (CD 11a, CD 11b, CD 11c, and CD 18) were measured perioperatively as indicators of the inflammatory response to surgery. Core temperatures were monitored in the intensive care unit to determine the incidence of postoperative hyperthermia (temperature >38.0 degrees C).

RESULTS

IL-6 and IL-8 concentrations increased in all patients after CPB. The increase in serum IL-6 levels was significantly attenuated in the morphine group compared to the fentanyl group at 3 and 24 h post-CPB (P < 0.05). Reductions in expression of neutrophil adhesion molecules were observed in both groups 15 min and 3 h post-CPB; however, a significantly larger reduction in CD 11b and CD 18 expression was noted in patients receiving morphine (P < 0.05). The incidence of postoperative hyperthermia was more frequent in the fentanyl group (73%) compared to the morphine group (0%, P < 0.05).

CONCLUSIONS

Compared with fentanyl, the administration of morphine as part of balanced anesthetic technique suppressed several components the inflammatory response (IL-6, CD 11b, CD 18, postoperative hyperthermia) to cardiac surgery and CPB.

The Release of Systemic Inflammatory Mediators Is Independent of Cardiopulmonary Bypass Temperature

OBJECTIVE

The aim of this study was to investigate the effect of systemic CPB temperature on the production of the key mediators of the systemic inflammatory response to coronary artery bypass graft (CABG) surgery.

DESIGN

Randomized clinical study.

SETTING

University hospital.

PARTICIPANTS

Thirty patients undergoing first-time CABG surgery.

INTERVENTIONS

The patients were randomized to hypothermic (32 degrees C, n = 15) or normothermic (36 degrees C, n = 15) CPB.

MEASUREMENTS AND MAIN RESULTS

Plasma interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP), cortisol, and neutrophils were measured the day before operation, at closure of the sternum, and 4, 16, and 44 hours later. The cytokine, CRP, cortisol, and neutrophil responses were independent of temperature during CPB with peak concentrations of IL-10 at closure of the sternum followed by IL-6, IL-8, cortisol, neutrophils, and finally CRP. A correlation between maximal plasma concentrations of IL-10 and cortisol was seen in both groups after surgery (p = 0.02). Drainage after surgery was lower after normothermic CPB (p=0.02), with no difference in the requirement for blood transfusion. All patients were discharged from the intensive care unit within 24 hours after surgery.

CONCLUSIONS

The release of systemic inflammatory mediators after cardiac surgery was independent of mild hypothermia (32 degrees C) versus normothermia (36 degrees C) during CPB.

Remifentanil or sufentanil for coronary surgery

BACKGROUND AND OBJECTIVE

High-dose opioid anaesthesia contributes to decreasing metabolic and hormonal stress responses in patients undergoing cardiac surgery. However, the increase in context-sensitive half-life of opioids given as a high-dose regimen can affect postoperative respiratory recovery. In contrast, remifentanil can be given in high doses without prolonging context-sensitive half-life due to its rapid metabolism. Therefore, we performed a prospective, randomized trial to compare anaesthesia consisting of propofol/remifentanil or propofol/sufentanil with regard to postoperative respiratory function and outcome.

METHODS

Patients undergoing coronary artery bypass grafting were randomized to a propofol/remifentanil (0.5-1.0 microg kg(-1) min(-1)) or propofol/sufentanil (30-40 ng kg(-1) min(-1)) based anaesthetic. Carbon dioxide response, forced expiratory volume in one second, vital capacity, and functional residual capacity were measured 1 day prior to the operation, 1 h before extubation, 1, 24 and 72 h after extubation. In addition, the incidence of atelectasis, pulmonary infiltrates, intensive care unit and postoperative length of stay were compared. Patients and physicians were blinded to the treatment group.

RESULTS

Twenty-five patients in each treatment group completed the study. There was no difference between patients of the treatment groups regarding demographics, risk- or pain scores. In all patients, carbon dioxide response, forced expiratory volume in one second, vital capacity and functional residual capacity were decreased postoperatively compared to baseline. Patients randomized to remifentanil had less depression of carbon dioxide response, less atelectasis and shorter postoperative length of stay (12 d vs. 10 d) than after sufentanil (P < 0.05).

CONCLUSIONS

Intraoperative use of high-dose remifentanil for coronary artery bypass grafting may be associated with improved recovery of pulmonary function and shorter postoperative hospital length of stay than sufentanil.

Anaesthesia and the acute phase protein response in children undergoing circumcision

Concentrations of acute phase proteins (CRP: C-reactive protein, albumin) change during surgery. We investigated the acute phase response to circumcision and the effects of anaesthesia on this response. The children were divided into four groups; group 1 (intratracheal general anaesthesia, n=40), group 2 (general anaesthesia with mask, n=20), group 3 (ketamine, n=20), group 4 (local anaesthesia, n=35). Blood samples were obtained, 24 hours before circumcision, after premedication, and 24 hours after circumcision. CRP and albumin before circumcision were comparable for all groups. There was no increase in CRP, and albumin remained steady throughout the study. No difference was observed among the groups, and related to anaesthesia. No responsiveness may be explained with the size of injured tissue or anatomical and histological type of preputium.

High thoracic epidural anesthesia and coronary artery disease in surgical and non-surgical patients

PURPOSE OF REVIEW

Even though high thoracic epidural anesthesia has been shown to be highly efficacious in the control of symptoms in refractory angina, its general use is still restricted. In patients who undergo coronary revascularization, however, the technique is becoming more and more popular. The present review outlines the use of high thoracic epidural anesthesia in patients with ischemic heart disease who underwent coronary revascularization in order to further reveal high thoracic epidural anesthesia's low complication rate and to analyze why physicians still refrain from using it more frequently.

RECENT FINDINGS

The incidence of severe hemodynamic complications after high thoracic epidural anesthesia is low in patients with coronary artery disease. The main advantage would be a myocardial sympathectomy leading to an improvement in the oxygen input-demand relationship. Likewise, a decrease in mortality due to respiratory complications could not be shown. In patients undergoing myocardial revascularization with full anticoagulation there is an increased risk of epidural hematoma formation. Its precise risk is difficult to evaluate. There is an overall low rate of epidural hematomas as a result of high thoracic epidural anesthesia. With the available data, the incidence has been estimated at between 1/1500 and 1/10,000.

SUMMARY

Epidural anesthesia does not decrease mortality or the incidence of myocardial infarction after coronary artery bypass grafting. It reduces the incidence of arrhythmias and respiratory complications and improves the quality of analgesia. High thoracic epidural anesthesia has been shown to be a safe and efficient technique for refractory angina that reduces the frequency of ischemic events and improves the clinical condition of patients.

An analysis of oxygen consumption and oxygen delivery in euthermic infants after cardiopulmonary bypass with modified ultrafiltration

BACKGROUND

The balance between systemic oxygen consumption (VO2) and delivery (DO2) is impaired after cardiopulmonary bypass (CPB) and is related to systemic inflammatory response syndrome. We sought to assess VO2 and DO2 and their relationship with proinflammatory cytokines after CPB with the use of modified ultrafiltration (MUF) in infants.

METHODS

Sixteen infants, aged 1-11.5 months (median, 6.3 months), undergoing hypothermic CPB with MUF were studied during the first 12 hours after arrival in the intensive care unit (ICU). The central temperature was maintained at 36.8-37.1 degrees C using external cooling or warming. VO2 was continuously measured using respiratory mass spectrometry. Arterial blood samples for the tumor necrosis factor (TNF), interleukin-6 (IL-6), and interleukin-8 (IL-8) were taken and DO2 was calculated using the Fick principle on arrival at the ICU, and 2, 4, 8, and 12 hours postoperatively. Cytokines were additionally measured after induction of anesthesia and at the end of MUF.

RESULTS

VO2 significantly decreased by 18.8% during the study period. DO2 was depressed throughout this period and reached a nadir at 8 hours (357.1 +/- 136.2 ml x min(-1) x m(-2)). The decrease in cytokines was accompanied with the decrease in VO2 despite varied relationships between the levels of each of the cytokines and VO2 measurements.

CONCLUSIONS

Our data indicate an unusual continuous decrease in VO2 during the first 12 hours after CPB in infants. Control of body temperature to maintain euthermia in addition to the use of MUF may be beneficial to the balance between VO2 and DO2 in the early postoperative period.

Effects of general anaesthesia on inflammation

General anaesthesia accompanied by surgical stress may influence the inflammatory responses that are essential for maintaining the homeostatic state during the postoperative course. Severe dysregulation of the inflammatory process may provoke or aggravate postoperative complications, e.g. increased susceptibility to infections, inadequate stress reactions and hypercatabolism. Anaesthetics have been suspected of impairing various functions of the immune system either directly, by disturbing the functions of immune-competent cells, or indirectly by modulating the stress response. In the past, conflicting data on the possible immunological side effects of anaesthetics have been published. Potential reasons for these controversial findings include heterogeneous patient study groups with diverse pre-existing diseases, lack of standardisation of surgical procedures, major differences in the length and severity of surgical tissue injury and a small number of randomised studies. Although the immunological effects are of minor consequence in subjects with normal immune functions, the suppression of cellular and humoral immunity following surgery and general anaesthesia may be relevant in patients with pre-existing immune disorders.

Blood pressure and heart rate variability changes during cardiac surgery with cardiopulmonary bypass

This study investigated patients undergoing elective cardiac surgery to evaluate the effects of cardiopulmonary bypass (CPB) on the spontaneous variability of mean arterial pressure (MAP) and heart rate (HR). Forty-one adult patients receiving different cardiovascular system drugs were included in the study. Patients were divided into three groups: no preoperative pharmacological cardiovascular treatment (n = 12), beta-blocker (BB) (n = 13), and angiotensin-converting enzyme inhibition (ACEI) (n = 16). MAP was recorded before anaesthesia until the end of surgery. MAP and HR variability was analysed in very low- (VLF), low- (LF) and high-frequency bands. The LF spectral component of MAP was observed to decrease in patients under ACEI (-92%) or BB (-87%) following induction of anaesthesia. In addition, during CPB, VLF power decreased in BB group (-67%), and LF power decreased in ACEI group (-77%). Concerning HR, VLF spectral power decreased following anaesthesia in BB group (-74%). In addition, after CPB, VLF power reached lower value in ACEI group than in BB group (P < 0.05). LF spectral power of HR showed a large decrease after CPB in ACEI group (-89%). This study showed that MAP variability did not change during CPB in patients with no preoperative pharmacological cardiovascular treatment, suggesting an unaltered vascular control of MAP. Moreover, the change in LF spectral power of MAP in ACEI and BB groups, suggests that both the renin-angiotensin and sympathetic systems participate to the genesis of LF variability of MAP.

Plasma cytokines do not reflect expression of pro- and anti-inflammatory cytokine mRNA at organ level after cardiopulmonary bypass in neonatal pigs

BACKGROUND

Plasma concentrations of inflammatory markers are increased in response to the trauma of cardiac surgery and cardiopulmonary bypass (CPB). It is, however, unknown whether the plasma cytokine levels and cytokine mRNA expression at organ level reflect each other.

METHODS

Twenty-six piglets (17-19 days) were allocated to the sham-group (sternotomy only, n = 13) or to the CPB-group (sternotomy, 120 min CPB procedure with 60-min aortic cross-clamp, n = 13). The pigs were observed for 0.5 h or 4 h post-CPB. Plasma levels of IL-1beta, IL-6, IL-8 and IL-10 and mRNA expression of TNF-alpha, IL-1beta, IL-6, IL-8, IL-10 and iNOS in organs were registered with concomitant changes in oxygenation index (OI) and expiratory nitric oxide (NO).

RESULTS

In pigs killed 0.5 h post-CPB there was a significant increase in IL-10 mRNA in the lungs and kidneys compared with the sham-group. IL-1beta mRNA was detectable in the kidneys and lungs of the CPB-pigs, while IL-6 mRNA was up regulated only in lungs. In pigs killed 4 h post-CPB a significantly higher IL-6 mRNA was found in heart tissue and a lower IL-10 mRNA was found in lungs of CPB pigs compared with the sham-group. There was a concomitant significant increase in OI and increased plasma IL-8 and IL-10 concentrations in the CPB-pigs compared with the sham-pigs.

CONCLUSION

The cytokine mRNA expression pattern was very different for the pigs killed already 0.5 h after the CPB procedure compared with the pigs killed 4 h post-CPB. The plasma cytokine levels poorly reflected mRNA expression of the pro- and anti-inflammatory cytokines.

The effects of anesthetic techniques on acute phase response at delivery (anesthesia and acute phase response)

OBJECTIVES

To investigate the effects of anesthetic techniques and delivery types on stress response during uncomplicated delivery.

DESIGN AND METHODS

Forty pregnant women at term were divided into four groups. Group-I, cesarean section with general anesthesia; Group-II, section with spinal anesthesia; Group-III, section with epidural anesthesia; and Group-IV, vaginal delivery with epidural analgesia. C-reactive protein and albumin were measured on hospital admission, immediately after delivery and 24 h later.

RESULTS

Albumin and CRP levels decreased significantly in Group-II and Group-III, just after delivery. CRP increased significantly in all groups at the 24(th) hour of delivery. The effect of hemodilution on CRP and Albumin, due to volume loading, during spinal and epidural anesthesia disappeared after 24 h.

CONCLUSION

We found no influence of anesthetic techniques on acute phase response except hemodilution effect. In the view of delivery types, vaginal delivery caused less stress response than section.

Tumor necrosis factor and clinical and metabolic courses after cardiac surgery in children

OBJECTIVE

This study was undertaken to determine the relationship between plasma tumor necrosis factor concentrations and hemodynamic and metabolic parameters during the postoperative clinical course in children undergoing cardiac surgery.

METHODS

Tumor necrosis factor levels of 10 consecutive children undergoing surgery for repair of congenital heart defects were analyzed in blood samples drawn at predetermined time points during surgery and up to 24 hours thereafter. Clinical data were collected at these times for correlation to tumor necrosis factor levels.

RESULTS

All the patients survived. Tumor necrosis factor was detected in all 10 children. Tumor necrosis factor levels declined after induction of general anesthesia (201 +/- 65 pg/mL) steadily decreasing during surgery, reaching 80 +/- 50 pg/mL at 24 hours after the operation. Tumor necrosis factor levels were found to be inversely correlated with mean blood pressure values and indicators of acidosis (bicarbonate levels and base excess, P <.03). They were not correlated with the durations of cardiopulmonary bypass and aortic crossclamping.

CONCLUSIONS

Tumor necrosis factor released into the circulation during and after pediatric cardiac surgery under cardiopulmonary bypass may be related to the hemodynamic and acid-base changes observed after cardiac surgery. Elucidation of the relationship between tumor necrosis factor and patient outcome in high-risk patients awaits further studies.

Common promoter variant in cyclooxygenase-2 represses gene expression: evidence of role in acute-phase inflammatory response

OBJECTIVE

Cyclooxygenase (COX)-2 is a key regulatory enzyme in the synthesis of prostanoids associated with trauma and inflammation. We investigated the COX-2 gene for functional variants that may influence susceptibility to disease.

METHODS AND RESULTS

The promoter of COX-2 was screened for variants in healthy subjects by use of polymerase chain reaction-based methods. Promoter activity was investigated by using reporter expression experiments in human lung fibroblasts. Patients undergoing coronary artery bypass graft surgery, with measurements of plasma markers linked to COX-2 activity, were genotyped for association studies. A common COX-2 promoter variant, -765G>C, was found and shown to be carried by >25% of a group of healthy UK subjects. The -765C allele had significantly lower promoter activity compared with -765G, basally (28+/-3% lower, P<0.005) and in serum-stimulated cells (31+/-2% lower, P<0.005). In patients subjected to coronary artery bypass graft surgery, the magnitude of rise in levels of C-reactive protein (CRP) was strongly genotype dependent. Compared with -765G homozygotes, patients carrying the -765C allele had significantly lower plasma CRP levels at 1 to 4 days after surgery (14% lower at the peak of CRP levels on day 3, P<0.05 for all time points).

CONCLUSIONS

For several acute and chronic inflammatory diseases, -765G>C may influence the variability of response observed.

Ketamine attenuates neutrophil activation after cardiopulmonary bypass

Surgery is associated with activation of neutrophils and their influx into affected tissue. The pathogenic role of superoxide production generated by activated neutrophils has been documented repeatedly. Ketamine suppresses neutrophil oxygen radical production in vitro. In the present study, we compared the effect of adding small-dose ketamine to opioids during the induction of general anesthesia on superoxide production by neutrophils after coronary artery bypass grafting (CABG). Thirty-five patients undergoing elective CABG were randomized to one of two groups and prospectively studied in a double-blinded manner. The patients received either ketamine 0.25 mg/kg or a similar volume of saline in addition to large-dose fentanyl anesthesia. Blood samples were drawn before the operation, immediately after cardiopulmonary bypass, 24 and 48 postoperative h, and on postoperative Days 3-6. Functional capacity of neutrophils was assessed by superoxide generation after stimulation with phorbol 12-myristate 13-acetate, opsonized zymosan, or formyl-methionyl-leucyl-phenylalanine. The addition of small-dose ketamine to general anesthesia attenuates increased production of the superoxide anion (O2-) by neutrophils without chemical stimulation and after stimulation with phorbol 12-myristate 13-acetate, formyl-methionyl-leucyl-phenylalanine, and opsonized zymosan for 4-6 days after CABG. In addition, ketamine attenuated the percentage of neutrophils on postoperative Days 2-6. In the Control group, superoxide production significantly increased compared with the baseline value. By contrast, in the Ketamine group, this difference was not significant.

IMPLICATIONS

In a randomized, double-blinded, prospective clinical study, we compared the effect of adding small-dose ketamine to opioids during general anesthesia on superoxide production and showed that ketamine suppressed the increase of superoxide anion production by neutrophils after coronary artery bypass grafting.

Neutrophils and platelets accumulate in the heart, lungs, and kidneys after cardiopulmonary bypass in neonatal pigs

OBJECTIVE

Cardiac surgery with cardiopulmonary bypass elicits a systemic inflammatory response. An exaggerated response is associated with organ dysfunction and increased morbidity and mortality.

DESIGN

The aim of the present study was to investigate whether the cardiopulmonary bypass procedure in itself results in accumulation of isotope-labeled platelets, polymorphonuclear neutrophils, and fibrinogen at organ levels in neonatal pigs and to monitor changes in organ function.

SETTING

Pediatric cardiopulmonary bypass setup with 60 mins of aortic cross-clamp time and 120 mins of hypothermic cardiopulmonary bypass time.

SUBJECTS

Thirty piglets were allocated to sternotomy alone (sham group, n = 15) or to sternotomy and cardiopulmonary bypass (n = 15).

MEASUREMENTS AND MAIN RESULTS

Isotope-labeled autologous polymorphonuclear neutrophils, platelets, and commercially available fibrinogen were infused, and the specific accumulation at organ level was measured in a gamma counter 4 hrs after termination of cardiopulmonary bypass. Concomitant changes in oxygenation index and cardiac output were registered. Animals exposed to cardiopulmonary bypass showed a significantly higher technetium-99m-polymorphonuclear neutrophil accumulation in the lungs and kidneys, whereas indium-111-platelets accumulated in the heart and kidneys compared with the sham group. There was a significantly larger increase in oxygenation index and significantly larger decrease in cardiac output between the pre- and postcardiopulmonary bypass period in the cardiopulmonary bypass group compared with the sham group.

CONCLUSIONS

The cardiopulmonary bypass procedure without cardiac surgery elicits organ dysfunction in terms of impaired respiratory and hemodynamic function. Platelets and polymorphonuclear neutrophils were entrapped in the heart, lungs, and kidneys of cardiopulmonary bypass animals, indicating that cell accumulation may contribute to the developing organ dysfunction.