Chronic postsurgical pain in patients 5 years after cardiac surgery: A prospective cohort study.

BACKGROUND: Chronic postsurgical pain (CPSP) is a common complication after many surgical procedures, including cardiac surgery. The prevalence of CPSP after cardiac surgery ranges from 9.5% to 56%. Most studies on CPSP after cardiac surgery are retrospective and long-term prospective studies are scarce. The aim of this study was to follow CPSP and health-related quality of life (HRQOL) prospectively in a cohort of patients, emphasizing the prevalence from 12 months to 5 years. METHODS: A total of 534 patients (23% ≥75 years, 67% men) were consecutively included before surgery. Study-specific questionnaires and the Brief Pain Inventory (BPI) were used to measure CPSP at baseline, 12 months and 5-year follow-up. Short-Form Health Survey (SF-36) was used to measure HRQOL. RESULTS: Among 458 patients who were alive after 5 years, 82% responded (n = 373). The majority, 89.8% (335/373), did not report CPSP, neither 12 months nor 5 years after surgery. Among the 38 patients who reported CPSP after 12 months, 24 (63%) patients did not report CPSP after 5 years. The overall prevalence of CPSP after 5 years was 3.8% (14/373). Patients reporting CPSP and resolved CPSP had lower scores on HRQOL and more pain preoperatively than patients who did not report CPSP. CONCLUSIONS: The prevalence of CPSP was lower in this study than previously reported. Among the patients reporting CPSP at 12 months, 63% did not report CPSP after 5 years. Hence, the observed decline in CPSP is in line with studies evaluating CPSP in noncardiac surgery. SIGNIFICANCE: The prevalence of chronic postsurgical pain (CPSP) at 5 years after surgery of 3.8% is lower than previously reported. The majority of patients reporting CPSP after 12 months did not report CPSP after 5 years.

Genetic variation influences the risk of bleeding after cardiac surgery: novel associations and validation of previous findings.

BACKGROUND: Severe post-operative bleeding in cardiac surgery is associated with increased morbidity and mortality. We hypothesized that variation in genetic susceptibility contributes to post-operative bleeding in addition to clinical factors. METHODS: We included 1036 adults undergoing cardiac surgery with cardiopulmonary bypass. Two different endpoints for excessive post-operative bleeding were used, either defined as blood loss exceeding 2 ml/kg/h the first 4 h post-operatively or a composite including bleeding, transfusions, and reoperations. Twenty-two single nucleotide polymorphisms (SNPs) central in the coagulation and fibrinolysis systems or in platelet membrane receptors were genotyped, focusing on replication of earlier non-replicated findings and exploration of potential novel associations. Using logistic regression, significant SNPs were added to a model with only clinical variables to evaluate whether the genetic variables provided additional information. RESULTS: Univariate tests identified rs1799809 (located in the promoter region of the PROC gene), rs27646 and rs1062535 (in the ITGA2 gene), rs630014 (in the ABO gene), and rs6048 (in the F9 gene) as significantly associated with excessive post-operative bleeding (P < 0.05, P-values confirmed by permutation). The SNPs were significant also after adjustment with clinical variables, showing almost unchanged odds ratios except for rs1799809 (P = 0.06). Addition of the genetic covariates to a logistic regression model with clinical variables significantly improved the model (P < 0.01). CONCLUSION: We identified five SNPs associated with post-operative bleeding after cardiac surgery, of which two validated previously published associations. Addition of genetic information to models with only clinical variables improved the models. Our results indicate that common genetic variations significantly influence post-operative bleeding after cardiac surgery.

Genetic and clinical risk factors for fluid overload following open-heart surgery.

BACKGROUND: Post-operative fluid overload following cardiac surgery is associated with increased morbidity and mortality. We hypothesised that genetic variations and pre-operative clinical factors predispose some patients to post-operative fluid overload. METHODS: Perioperative variables were collected prospectively for 1026 consecutive adults undergoing open-heart surgery at St. Olavs University Hospital, Norway from 2008-2010. Post-operative fluid overload was defined as a post-operative fluid balance/kg ≥ the 90th percentile of the study population. Genotyping was performed for 31 single-nucleotide polymorphisms related to inflammatory/vascular responses or previously associated with complications following open-heart surgery. Data were analysed using logistic regression modelling, and the findings were internally validated by bootstrapping (n = 100). RESULTS: Homozygous carriers of the common G allele of rs12917707 in the UMOD gene had a 2.2 times greater risk of post-operative fluid overload (P = 0.005) after adjustment for significant clinical variables (age, duration of cardiopulmonary bypass, and intraoperative red cell transfusion). A genetic risk score including 14 single-nucleotide polymorphisms was independently associated with post-operative fluid overload (P = 0.001). The number of risk alleles was linearly associated with the frequency of fluid overload (odds ratio per risk allele 1.153, 95 % confidence interval 1.056-1.258). Nagelkerke's R(2) increased with 7.5% to a total of 25% for the combined clinical and genetic model. Hemofiltration did not reduce the risk. CONCLUSION: A common variation in the UMOD gene previously shown to be related to renal function was associated with increased risk of post-operative fluid overload following cardiac surgery. Our findings support a genetic susceptibility to disturbed fluid handling following cardiac surgery.

Pre-operative and intraoperative determinants for prolonged ventilation following adult cardiac surgery.

BACKGROUND: Prolonged ventilation is a serious complication after cardiac surgery, but few risk prediction models exist. Our objectives were to develop a specific risk prediction model based on pre-operative variables, to identify whether selected intraoperative variables could improve prediction, and to compare our model with the EuroSCORE. METHODS: Data from 5027 patients undergoing open-heart surgery in 2000-2007 were used for logistic regression model development. Internal validation was performed by bootstrapping. Discrimination and calibration were assessed with areas under the receiver operating characteristic curve (AUC) and the Hosmer-Lemeshow test. Our pre-operative model was compared with predictions based on the additive and logistic EuroSCORE. RESULTS: Age, previous cardiac surgery, peripheral arterial disease, left ventricular hypertrophy, chronic pulmonary disease, renal insufficiency, pre-operative hemoglobin concentration, urgent or emergency operation, and operation other than isolated coronary artery bypass grafting were identified as pre-operative predictors for prolonged ventilation (model I). Discrimination and accuracy were excellent (AUC: 0.848 and shrinkage factor: 94%). Calibration was good (Hosmer-Lemeshow test: P = 0.43). Inclusion of a few intraoperative variables somewhat improved the model, increasing shrinkage factors (96%) and discrimination ability (AUC model II = 0.870 and model III = 0.875 for two alternative such models). Our pre-operative model showed better performance than the logistic or additive EuroSCORE. CONCLUSIONS: The pre-operative risk prediction model for prolonged ventilation with easily obtainable variables in routine clinical work performed well and was only slightly improved by inclusion of intraoperative variables. Performance was better than with the EuroSCORE.

Mortality risk prediction in cardiac surgery: comparing a novel model with the EuroSCORE.

BACKGROUND: Several models for prediction of early mortality after open-heart surgery have been developed. Our objectives were to develop a local mortality risk prediction model, compare it with the European System for Cardiac Operative Risk Evaluation (EuroSCORE), and investigate whether the addition of intra-operative variables could enhance the accuracy of risk prediction. METHODS: All 5029 patients undergoing open-heart surgery in 2000-2007 were included in the study. Logistic regression with bootstrap methods was used to develop a pre-operative risk prediction model for in-hospital mortality. Next, several intra-operative variables were added to the pre-operative model. Calibration and discrimination were assessed, and the model was internally validated for prediction in future datasets. We thereafter compared the pre-operative model with the additive and logistic EuroSCOREs. RESULTS: Our pre-operative model included eight risk factors that are routinely registered in our department: age, gender, degree of urgency, operation type, previous cardiac surgery, and renal, cardiac, and pulmonary dysfunction. The model estimated mortality accurately throughout the dataset except in the 1% of patients at extremely high risk, in which mortality was somewhat overestimated. The estimated shrinkage factor was 0.930. The areas under the receiver operating characteristic curve for our pre-operative model and the logistic EuroSCORE were 0.857(0.823-0.891) and 0.821(0.785-0.857) (P=0.02). There was no significant difference in performance between the pre-operative and the intra-operative model (P>0.10). CONCLUSION: Our pre-operative model was simple and easy to use, and showed good predictive ability in our population. Internal validation indicated that it would accurately predict mortality in a future dataset.

Chronic pain after cardiac surgery: a prospective study.

BACKGROUND: Chronic pain is a complication of several surgical procedures. The prevalence of chronic pain reported after cardiac surgery varies from 18% to 61%. However, most studies are retrospective, do not use validated instruments for pain measurement or include only pain at the sternum site. The aim of the present study was to assess chronic pain and health-related quality of life (HRQOL) after cardiac surgery. METHODS: In a prospective, population-based study, we included 534 patients (413 males) and assessed chronic pain and HRQOL before, 6 months after, and 12 months after cardiac surgery. Pain was measured by the Brief Pain Inventory, while HRQOL was measured by the Short-Form 36 (SF-36). RESULTS: Five hundred and twenty-one patients were alive 12 months after surgery; 462 (89%) and 465 (89%) responded after 6 and 12 months, respectively. Chronic pain was reported by 11% of the patients at both measurements. Younger age was associated with chronic pain [odds ratio 0.7 (95% confidence interval: 0.5-0.9)] at 12 months. Patients with chronic pain reported lower scores on seven of eight SF-36 subscales. DISCUSSION: In conclusion, we observed a lower prevalence of chronic pain after cardiac surgery than in previous studies. Still, more than one out of 10 patients reported chronic pain after cardiac surgery. Chronic pain appears to affect HRQOL. Thus, given the large number of patients subjected to cardiac surgery, this study confirms that chronic pain after cardiac surgery is an important health care issue.

Sonoclot analysis in elderly compared with younger patients undergoing coronary surgery.

BACKGROUND: The Sonoclot analyzer is a point-of-care method for assessment of the clotting mechanism in whole blood. The results are available within 20 min. The aim of the present study was to investigate whether repeated Sonoclot analyses could identify peri-operative differences in hemostatic function between elderly and younger patients undergoing coronary artery bypass grafting (CABG). In addition, we investigated whether Sonoclot analyses could identify disturbances in hemostatic function leading to post-operative bleeding. METHODS: Twenty-five elderly and 25 younger patients undergoing CABG were included. Blood samples for Sonoclot analyses were drawn pre-operatively, during surgery, and during the first 20 post-operative hours. The Sonoclot variables sonACT, clot rate, time-to-peak, amplitude of the peak, and R3 were analyzed, and the results were compared between the two groups. Post-operative blood loss volumes were recorded and correlated to the Sonoclot variables. The Sonoclot variables were also correlated to previously reported results on various hemostatic variables measured in the same patient population. RESULTS: There was a significant difference in sonACT between the two groups (P=0.018). There were no differences between the groups in any of the other Sonoclot variables. There were no significant correlations between any of the Sonoclot variables and post-operative bleeding, or between the Sonoclot variables and other hemostatic variables. CONCLUSIONS: The difference in sonACT between the two groups indicates a reduced hemostatic function in the elderly patients. However, repeated Sonoclot analyses were not able to identify more specific disturbances in hemostatic function, and did not predict increased post-operative bleeding.

Rectal lactate levels in endoluminal microdialysate during routine coronary surgery.

The aim of this prospective study was to determine the feasibility of intestinal endoluminal microdialysis as a new method for clinical monitoring of the adequacy of splanchnic perfusion in the large bowel. A microdialysis catheter for continuous lactate, glycerol, glucose and pyruvate measurements attached to a tonometric catheter was placed into the lumen of the recto-sigmoid junction prior to surgery in 13 patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB). Lactate was also measured in blood and muscle. CPB was associated with a 10-fold increase in luminal lactate from 0.16 (0.01) to 1.67 (0.38) mmol x l(-1) (p < 0.001). Muscular lactate increased from baseline levels 1.20 (0.21) to 1.77 (0.36) mmol x l(-1) during CPB (p = 0.01), but the muscular lactate-pyruvate ratio remained unchanged. Arterial lactate increased only slightly from 0.9 (0.05) to 1.1 (0.06) mmol x l(-1) (p = 0.027) during CPB. Increased lactate concentrations in the large bowel during CPB are suggestive of local lactate production consistent with impaired oxygen delivery. Intestinal endoluminal microdialysis is a potential clinically applicable method for monitoring intestinal metabolism. Combined with tonometry, microdialysis provides the opportunity to monitor both circulation and metabolism in the rectal mucosa.

Frequent sampling allows detection of short and rapid surges of exhaled ethane during cardiac surgery.

During cardiopulmonary bypass (CPB), hypoperfusion and reperfusion may cause oxidative stress and lipid peroxidation that generates ethane. The aim of this pilot study was to assess the feasibility of frequent sampling of exhaled ethane during cardiac surgery. After approval of the Research Ethics Committee, 10 patients undergoing combined aortic valve and coronary artery bypass surgery were enrolled. Breath samples were drawn in the perioperative period and analyzed by a rapid, sensitive and validated gas-chromatographic method. Increased exhaled ethane was regularly seen following sternotomy, after the start of CPB and after aortic clamp removal, whereas no change was seen after termination of bypass. In one patient, the maximum increase in exhaled ethane was 30-fold. Peak durations lasted only 2-4 min. This study demonstrates that frequent sampling of breath ethane is feasible in a clinical setting, allowing detection of rapid ethane surges of short duration.

Spinal fluid dynamics during thoracic- and thoracoabdominal aortic surgery.

AIM: The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits. METHODS: Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded. RESULTS: Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure. CONCLUSIONS: A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.

Post-operative myocardial dysfunction does not affect the physiological response to early mobilization after coronary artery bypass grafting.

BACKGROUND: An acute increase in oxygen demand can be compensated for either by increased cardiac index (CI) or increased oxygen extraction, resulting in reduced mixed venous oxygen saturation (SvO2). We tested the hypothesis that post-operative cardiac dysfunction may explain why oxygen extraction alone is increased during early mobilization after cardiac surgery. METHODS: Twenty patients with a pre-operative ejection fraction > 50% were included in an open prospective observational study comparing the changes in SvO2 and hemodynamics during mobilizations immediately prior to surgery and on the first post-operative morning. RESULTS: Mobilization induced an absolute reduction in SvO2 of 17.7 +/- 7.4% pre- and 19.0 +/- 5.5% post-operatively (NS). ANOVA for a series of measurements throughout the mobilization sequence identified no different effect on SvO2 between pre- and post-operative mobilizations (P = 0.567). The SvO2 level was reduced post-operatively resulting in a SvO2 during standing exercise of 55% before and 49% after the surgery (P < 0.01). Mobilization increased the heart rate (HR) and decreased the stroke volume index (SVI), leaving CI unchanged. This response was similar pre- and post-operatively (NS). Compared with pre-operative measurements, CI and HR increased post-operatively while SVI remained unchanged despite elevated cardiac filling pressures and reduced systemic vascular resistance. The left ventricular stroke work index was reduced, indicating reduced myocardial performance. CONCLUSION: Myocardial function was reduced on the first morning after coronary artery bypass grafting (CABG), but during post-operative mobilization this reduction did not significantly influence the changes in CI or SvO2.

Effects of autotransfusion of mediastinal shed blood on biochemical markers of myocardial damage in coronary surgery.

BACKGROUND: Previous studies have shown conflicting results regarding the effect of autotransfusion of mediastinal shed blood after coronary artery bypass grafting (CABG) on the serum levels of myocardial band (MB) isoenzymes of creatine kinase (CK-MB) and cardiac troponins. The effect of autotransfusion on serum levels of human heart fatty acid binding protein (H-FABP), another marker of myocardial necrosis, has not been studied. The aim of the present study was to investigate the effects of autotransfusion of mediastinal shed blood on the serum levels of CK-MB, cardiac troponin T (cTnT), and H-FABP after uncomplicated primary CABG. METHODS: Fifty patients were randomized to post-operative autotransfusion of mediastinal shed blood or no autotransfusion. Blood samples for the analysis of the biochemical markers of myocardial damage were drawn pre-operatively and 1, 4, 12, 24, 48, and 72 h after the termination of cardiopulmonary bypass. Samples from the mediastinal shed blood were collected after 1 and 4 h. RESULTS: The levels of the biochemical markers of myocardial injury were all markedly elevated in mediastinal shed blood. Autotransfusion did not significantly affect the serum levels of cTnT or H-FABP. However, during the early post-operative hours, there was a trend towards a higher level of cTnT and H-FABP in the autotransfusion group. During the first 24 h after surgery, the autotransfusion group had a significantly higher serum level of CK-MB. CONCLUSION: Post-operative autotransfusion of mediastinal shed blood may contribute to elevated serum levels of biochemical markers of myocardial injury.

Mixed venous oxygen desaturation during early mobilization after coronary artery bypass surgery.

BACKGROUND: Early postoperative mobilization induces a marked reduction in mixed venous oxygen saturation (S(v)O(2)) after aortic valve replacement. We investigated whether a similar desaturation occurs among coronary artery bypass grafting (CABG) patients, and if the desaturation was related to the preoperative ejection fraction (EF). METHODS: Thirty-one CABG patients with a wide range in EF were included in an open observational study. We recorded hemodynamic and oxygenation variables during mobilization on postoperative day 1 and day 2 using a pulmonary artery catheter. RESULTS: Patients with an EF ranging from 24 to 87% were mobilized without clinical problems. S(v)O(2) at rest was 65.4 +/- 4.9% (mean +/- SD) on day 1 and 64.3 +/- 5.8% on day 2 (NS). During mobilization, cardiac index and oxygen delivery were reduced while oxygen consumption was increased (P-values: 0.000, 0.007 and 0.000, respectively). Consequently, oxygen extraction increased, resulting in a marked reduction in S(v)O(2)-42.9 +/- 8.3% on day 1 and 47.4 +/- 8.5% on day 2 (P = 0.025 between days). Several pre-, intra- and postoperative factors were tested as possible predictors for S(v)O(2) during mobilization. No factor contributed substantially. CONCLUSION: Patients with CABG exhibit a marked desaturation during early postoperative mobilization. Preoperative ejection fraction did not affect S(v)O(2) during exercise. The clinical consequences and underlying mechanism require further investigation.

Changes in hemodynamics and acid-base balance during cross-clamping of the descending thoracic aorta. A study in patients operated on for thoracic and thoracoabdominal aortic aneurysm.

AIM OF THE STUDY: In the clinical situation there is discrepancy between various investigations regarding the cardiac response of thoracic aortic cross-clamping. The aim was therefore to investigate the hemodynamic response and blood gases during proximal aortic cross-clamping (XC) in patients operated for descending thoracic and thoracoabdominal aortic aneurysm without circulatory support. PATIENTS AND METHODS: Altogether 51 patients operated on for thoracoabdominal (n=31) or descending thoracic aortic aneurysm (n=20) were included in the investigation. All patients were operated with aortic XC, but no circulatory support was applied. Hemodynamic variables and blood gases were recorded before and during XC. RESULTS: A significant increase in cardiac output during XC from 4.7 to 6.0 liters/min was observed (p<0.01). There was a similar percentual increase in heart rate and also the proximal systolic blood pressure increased. A metabolic acidosis occurred during XC. CONCLUSION: Cardiac output was significantly increased during XC in patients operated on for thoracoabdominal or descending thoracic aneurysm using direct aortic XC without circulatory support. Simultaneously, the heart rate was increased and there was a hyperdynamic circulatory state proximal to the aortic clamp. Redistribution of the blood volume in addition to catecholamine release may be responsible for the observed changes. These observations may influence the selection of operative strategy for some of these patients.

Supplemental remifentanil during coronary artery bypass grafting is followed by a transient postoperative cardiac depression.

BACKGROUND: The pharmacokinetic properties of the short-acting micro opioid receptor-agonist remifentanil makes it possible to give cardiac surgical patients a deep intraoperative anesthesia without experiencing postoperative respiratory depression and a prolonged stay in the intensive care unit (ICU). However, previous investigations have shown that patients who received remifentanil required additional analgesia during the early postoperative period as compared to patients who received fentanyl. The aim of the present study therefore was to investigate the effects of supplementing remifentanil to a standard fentanyl-based anesthesia in coronary artery bypass grafting (CABG). METHODS: The study was prospective, randomized, double-blind, and placebo-controlled. Twenty male patients aged 55-70 years were included. All patients received a standard fentanyl and isoflurane-based anesthesia. In addition, the patients were randomized to receive either remifentanil 0.5 micro g kg(-1) min(-1) or placebo during surgery. Hemodynamic recordings and measurements of blood glucose and plasma adrenaline and noradrenaline were performed intra- and postoperatively. RESULTS: Remifentanil reduced the hemodynamic and metabolic response to surgical stress compared to the standard fentanyl-based anesthetic regimen. However, the patients in the remifentanil group had a lower cardiac output (CO), left ventricular stroke work index (LVSWI), and mixed venous oxygen saturation (SvO(2)), and a higher central venous pressure (CVP) than the patients in the placebo group during the early postoperative phase, indicating a postoperative cardiac depression in the remifentanil group. CONCLUSION: In CABG, remifentanil reduces the hemodynamic and metabolic responses during surgery but seems to give a cardiac depression in the early postoperative phase.

Effects of thoracic epidural analgesia on pulmonary function after coronary artery bypass surgery.

OBJECTIVE: A substantial reduction in lung volumes and pulmonary function follows cardiac surgery. Pain may prevent effective breathing and coughing, and as thoracic epidural analgesia may reduce postoperative pain, we investigated the effect of epidural analgesia on pulmonary function. METHODS: Fifty-four male patients, under 65 years and with an ejection fraction of more than 0.5, were randomized into two groups: a control group receiving high-dose fentanyl anaesthesia and an epidural group receiving low-dose fentanyl anaesthesia + thoracic epidural analgesia. Time to awakening and time to extubation were recorded. Further, spirometric data, arterial oxygenation, pulmonary shunt, haemodynamics, use of vasoactive drugs and fluid balance were followed for up to 6 days postoperatively. RESULTS: Patients with low-dose fentanyl and epidural analgesia awoke (1.6 vs 3.6 h) and were extubated (5.4 vs 10.8 h) significantly earlier than control group patients. A 50-70% reduction in forced vital capacity, forced expiratory volume in 1 s (FEV1.0) and peak expiratory flow rate (PEFR) was seen after surgery, but higher FEV1.0 and PEFR on days 2 and 3 were seen in the epidural group than in the control group. Pulmonary shunt and alveolo-arterial oxygen difference increased similarly in both groups, whereas oxygen delivery and mixed venous oxygen saturation were higher in the epidural group. Epidural analgesia gave better control of the postoperative hyperdynamic circulation. CONCLUSIONS: Thoracic epidural analgesia yields a slight, but significant, improvement in pulmonary function, most likely due to a more profound postoperative analgesia.

Effects of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass surgery.

OBJECTIVE: A possible influence of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass grafting was investigated. DESIGN: The study was prospective and randomized. SETTING: The study was performed in a university hospital. PARTICIPANTS: Thirty male patients less than 65 years of age and with ejection fraction greater than 0.5 participated. They were randomized into 3 groups: the high fentanyl (HF) group receiving high-dose fentanyl (55 micrograms/kg) anesthesia, the HF + thoracic epidural analgesia (TEA) group receiving the same general anesthesia plus thoracic epidural analgesia, and the low-fentanyl (LF) + TEA group receiving low-dose fentanyl (15 micrograms/kg) anesthesia plus thoracic epidural analgesia. INTERVENTIONS: A thoracic epidural catheter, a peripheral and central venous catheter, a radial artery catheter, a thermodilution pulmonary artery catheter, and a coronary sinus reverse thermodilution catheter were inserted. MEASUREMENTS AND MAIN RESULTS: Coronary circulatory parameters, myocardial oxygenation, and myocardial substrate utilization were investigated before bypass and for 9 hours after bypass. Before bypass, the most striking finding was a reduction in myocardial lactate extraction in all groups, but also coronary flow and myocardial oxygen consumption decreased compared with baseline. After bypass, the only significant finding was a lower coronary vascular resistance early postoperatively in the epidural groups, but coronary blood flow was adequate in all groups. Myocardial metabolism was essentially unchanged both with and without epidural analgesia after bypass. CONCLUSION: With regard to the coronary circulation and myocardial metabolism, no hard data supporting the use of thoracic epidural analgesia in coronary artery bypass grafting were found.

Haemodynamic effects of thoracic epidural anaesthesia during proximal aortic cross-clamping in pigs.

Cross-clamping (XC) of the thoracic aorta induces a hyperdynamic circulation proximal to the aortic clamp. In this investigation, the effects of thoracic epidural anaesthesia (TEA) on the haemodynamic response to XC were studied in pigs. Seventeen pigs were anaesthetized with ketamine, and the thoracic aorta was cross-clamped for 30 minutes. In eight of the animals (TEA-group) a thoracic epidural block (3 ml 0.5% bupivacaine) was added to the general anaesthesia. Prior to XC there was a lower heart rate (HR), cardiac output (CO) and mixed venous oxygen saturation (SvO2) in the TEA-group compared to the nine animals with general anasthesia only (control-group). During XC there was an increase in HR, CO, SvO2 and proximal aortic blood pressure (PPROX) in both groups, without differences between groups. Following aortic declamping central venous pressure (CVP), pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCWP) increased in both groups. Fifteen minutes after declamping, one animal in each group died. It was concluded that in this experimental model, TEA combined with general anaesthesia did not modify the haemodynamic response to XC of the thoracic aorta.

Thoracic epidural analgesia in aortocoronary bypass surgery. II: Effects on the endocrine metabolic response.

Thoracic epidural analgesia (TEA) may offer haemodynamic benefits for patients with coronary heart disease going through major surgery. This may-in part-be secondary to an effect on the endocrine and metabolic response to surgery. We therefore investigated the effect of TEA on the endocrine metabolic response to aortocoronary bypass surgery (ACBS). Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 micrograms.kg-1) anaesthesia, the HF+TEA group with the same fentanyl dose+TEA with 10 ml bupivacain 5 mg.ml-1, followed by 4 ml every hour, and the LF+TEA group receiving fentanyl 15 micrograms.kg-1 + TEA. Adrenalin, noradrenalin, systemic vascular resistance (SVR), glucose, cortisol, lactate and free fatty acids were followed during the operation and for 20 h postoperatively. A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and cortisol was noticed in all groups, but the increase was delayed in the epidural groups. Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone.