End Of Extracorporeal Circulation Research Articles

Uni-ventricular palliation vs. bi-ventricular repair: differential inflammatory response

BackgroundTo examine whether uni-ventricular palliation (UVP) and bi-ventricular repair (BVR) result in a different pattern of systemic inflammatory response to pediatric cardiac surgery with extra-corporeal circulation (ECC).MethodsIn 20 children (median age 39.5 months) undergoing either UVP (n = 12) or BVR (n = 8), plasma levels of the inflammatory cytokines TNF-α, IL-6, IL-10, and IL-12 and of procalcitonin (PCT), were measured before, during and after open cardiac surgery up to postoperative day (POD) 10.ResultsEpidemiologic, operative- and outcome variables were similar in both groups but post-operative central venous pressure that was higher in UVP. In the whole cohort, the inflammatory response was characterized by an early important, significant and parallel increase of IL-6 and IL-10 that reached their peak values either at the end of ECC (IL-10) or 4 h postoperatively (IL-6), respectively and by a significant and parallel decrease of TNF-α and IL-12 levels after connection to ECC, followed by a bi-phasic significant increase with a first peak 4 h after ECC and a second at POD 10, respectively. Patients after UVP showed a shift of the cytokine balance with lower IL-6- (p = 0.01) after connection to ECC, lower early post-operative TNF-α - (p = 0.02) and IL-12- (p = 0.04) concentrations and lower TNF-α/IL-10-ratio (p = 0.03) as compared with patients with BVR. Levels of PCT were similar in both groups.ConclusionsUVP is associated with an anti-inflammatory shift of the inflammatory response to cardiac surgery that might be related to the particular hemodynamic situation of patients with UVP.

Low-body-perfusion via an arterial sheath reduces inflammation after aortic arch reconstruction surgery

Pediatric cardiac surgeries involving aortic arch reconstruction are complex and require long cardiopulmonary bypass (CPB) times with deep hypothermic circulatory arrest (DHCA). Selective perfusion techniques have been developed to prevent the deleterious consequences of DHCA associated hypoperfusion. The effectivity of low body perfusion through cannulation of the femoral artery with an arterial sheath remains to be elucidated. We compared perfusion and inflammation in patients receiving selective antegrade cerebral perfusion (ACP) only to low body perfusion (LBP) in addition to ACP during DHCA for aortic arch reconstruction surgery. There was no difference in patient characteristics, cardiac pathologies, or performed procedures between ACP and LBP groups. Lactate levels increased after cardiac arrest in both groups. However, lactate levels were lower after 1 h reperfusion, at the end of extracorporeal circulation (ECC), and after surgery in LBP group compared to ACP only. Furthermore, creatinine was increased in ACP group on postoperative day 1 compared to LBP group but no acute kidney injury was observed in any group. IL-6 concentration increased in ACP group, while remained unchanged in LBP group compared to pre surgical values and were significantly lower compared to ACP group on postoperative days 1 and 2. LBP via an arterial sheath during cardiac arrest for aortic arch reconstruction surgery in addition to ACP, improves post ECC tissue perfusion as indicated by lower lactate levels and reduces creatinine levels suggesting milder kidney injury. LBP seems to prevent postoperative inflammation through a reduction in procedural duration or enhanced perfusion and thereby improves the outcome after aortic arch reconstruction surgery.

Platelet-leukocyte aggregates – a predictor for acute kidney injury after cardiac surgery

Background Acute kidney injury (AKI) is one of the most common complications after cardiac surgery. However, effective biomarker used for early diagnosis of AKI has not been identified. Platelet-leukocyte aggregates (PLAs) participate in inflammation and coagulation, leading to vascular lesions and tissue destruction. We designed a prospective study to assess whether PLAs can serve as a good biomarker for early diagnosis of AKI after cardiac surgery. Methods Patients with rheumatic heart disease scheduled to undergo valve replacement surgery were enrolled. Blood samples were collected at five timepoints as follows: (a) At baseline. (b) At the end of extracorporeal circulation. (c) Arrival at intensive care unit (ICU). (d) Four-hours after the admission to ICU. (e) Twenty hours after the admission to ICU. After collection, the samples were immediately used for PLAs measurement by flow cytometry. Results A total of 244 patients were registered, and 15 of them were diagnosed with AKI according to the serum creatinine of KDIGO guidelines. The PLAs levels in AKI group were significantly increased 20 h after surgery (two-way repeated measure analysis of variance, p < 0.01) compared with that at baseline. Patients whose preoperative PLAs were higher than 6.8% showed increased risk of developing AKI (multivariate logistic regression; p = 0.01; adjusted odds ratio, 1.05; 95% confidence interval, 1.01–1.09). Conclusion PLAs is an independent risk factor for AKI after valve replacement among patients with rheumatic heart disease.

Effects of dexmedetomidine on stress hormones in patients undergoing cardiac valve replacement: a randomized controlled trial

BackgroundStress response always occurs in cardiac valve replacement patients undergoing cardiopulmonary bypass (CPB).Methods60 patients undergoing cardiac valve replacement were recruited and randomized into control and Dex groups. Dex group received 1.0 μg·kg-1 of Dex for 10 min intravenously before anesthesia, followed by 0.5 μg·kg-1·h-1 of Dex, steadily administered throughout the procedure. And controlled group received the identical velocity of saline as Dex group. Plasma level of cortisol (Cor), epinephrine (E), norepinephrine (NE), and serotonin (5-HT) were evaluated at four timepoints: Before administration (T0), sawn sternum (T1), end of extracorporeal circulation (T2), and 24 h post operation (T3). General data of operation and recovery such as heart rate (HR), mean arterial pressure (MAP), intraoperative bispectral index (BIS), and hospitalization time in the intensive care unit (ICU) were also compared.ResultsIncrease of Cor, E, NE, and 5-HT for the Dex group was significant lesser than that in the control group (P < 0.05), and ICU hospitalization time and ventilator support time was significantly shorter in the Dex group. The proportion of patients discharged from the hospital with better prognosis was significantly higher than that in the control group, while there were no significant differences in hospitalization costs and vasoactive drugs use between the two groups.ConclusionsDex reduces plasma Cor, E and NE elevations in patients after CPB, alleviates the stress reaction of the body, shortens the hospitalization time and ventilator support time in ICU, and plays a positive role in the rehabilitation of patients undergoing cardiac valve replacement.Trial registrationChina Clinical Trial Registry (No. ChiCTR-IPR-17010954) March 22rd, 2017.

Pharmacokinetic characteristics and microbiologic appropriateness of cefazolin for perioperative antibiotic prophylaxis in elective cardiac surgery

ObjectiveAdequate levels of perioperative antibiotic prophylaxis are essential for prevention of surgical site infections. We examined pharmacokinetic details of 2 g cefazolin administered during induction of anesthesia with repeat dosing shortly after initiation of cardiopulmonary bypass (CPB) in cardiac surgery. MethodsTo identify the microbiologic flora targeted with prophylaxis, pre-, and postoperative swabs were taken from sternal skin. Blood samples for measurement of cefazolin were obtained in 24 patients. Drug levels were used for population pharmacokinetic modeling using Nonmem software (Icon Development Solutions, San Antonio, Tex). ResultsMore than 90% of bacteria on sternal skin were sensitive to cefazolin, indicating minimal inhibitory concentrations <8 mg/L. All serum levels of cefazolin were above 8 mg/L and might thus effectively prevent infection. Pharmacokinetic modeling in a 1-compartment model predicted a population mean clearance (CL) of 5.23 L/h and a volume of distribution (Vd) of 15.8 L. CPB increased Vd from 14.4 L to 22.1 L with a consecutive reduction to 18 L after the end of extracorporeal circulation. The final model implemented interindividual variability on CL and Vd, incorporating the covariates CPB and albumin on Vd and creatinine clearance on CL. Goodness-of-fit calculations showed that this model adequately describes the data derived from our clinical cohort. ConclusionsTwo grams of cefazolin at induction of anesthesia with a repeat dose after initiation of CPB ensures adequate drug levels to target a majority of pathogens of surgical site infections. Pharmacokinetic modeling demonstrated a significant influence of CPB on the volume of distribution and elimination of cefazolin. Other influences on pharmacokinetic parameters were albumin, protein, and creatinine clearance.

Impact of deep hypothermic circulatory arrest on the BIS index

Study Objective To investigate the influence of duration of deep hypothermic circulatory arrest (DHCA) on recovery of the bispectral index (BIS). Design Prospective cohort study. Setting Operating room of university teaching hospital. Patients 30 adult, ASA physical status III and IV patients scheduled for cardiac surgery with extracorporeal circulation (ECC) and DHCA. Interventions There were no study-specific interventions undertaken with the study patients. Measurements After induction of anesthesia, propofol and sufentanil were used for maintenance. Duration until BIS values reached indices of 10, 20, and 30 after DHCA was measured. ΔBIS was defined as the difference between BIS before the start of ECC and after DHCA at the same nasopharyngeal body temperature. Data are means ± SD (ranges). Main Results Duration of DHCA was 24 ± 15 min (8-71 min). The deepest nasopharyngeal temperature was 20.1 ± 2.7°C at the end of DHCA. BIS reduction was 1.8/°C. At the end of DHCA, BIS was 2 ± 6 and at the end of ECC, BIS was 33 ± 11. Duration until BIS reached a value of 10 (BIS10) was 23 ± 21 min (0-83 min); until BIS reached 20 (BIS20): 36 ± 36 min (0-140 min); and until BIS reached 30 (BIS30): 43 ± 29 min (1-130 min). Regression analysis between duration of DHCA and BIS10 was R = 0.76; BIS20: R = 0.67; and BIS30: R = 0.54. Conclusion Deep hypothermia influences BIS linearly. In addition, there appears to be a reasonable correlation between recovery of BIS values and duration of DHCA.

Relationship between N-terminal pro-B-type natriuretic peptide (Nt-proBNP) and cardiac cycle efficiency in cardiac surgery

N-terminal pro-B-type natriuretic peptide (Nt-proBNP) is a peptide released from myocardium in response to ventricular wall stress and dysfunction. Nt-proBNP plasma levels are elevated in a variety of cardiovascular disorders and are largely used for diagnosis and treatment of cardiac diseases. The cardiac cycle efficiency (CCE) is a haemodynamic variable that represents the left ventricle wall stress and the heart's effort to maintain an adequate blood flow to tissues. We investigated the relationship between Nt-proBNP and CCE values in patients undergoing cardiac surgery. Twenty-five patients undergoing aortic valve replacement were studied. Plasma Nt-proBNP concentrations were performed by electroluminescence immunoassay before starting surgery (t0), at the end of extracorporeal circulation (t1) and 3 hours after surgery (t2). CCE measurements were acquired at the same intervals and correlations with Nt-proBNP levels were calculated. Nt-proBNP plasma concentration was 1430 ± 341 pg/ml at t0, peaked significantly at t1 (2129 ± 561 pg/ml, p < 0.001) and moderately decreased at t2 (1924 ± 477 pg/ml, p < 0.05). A direct correlation between Nt-proBNP measured at t0 and t1 was found ( r = 0.91, p < 0.001). Overall, a negative correlation between CCE and proBNP values was found ( r = −0.89, p < 0.01). Correlations between CCE and Nt-proBNP were −0.91, −0.83 and −0.88, at t0, t1 and t2, respectively ( p < 0.01). Nt-proBNP levels reflect the severity of left ventricle dysfunction in patients undergoing cardiac surgery. CCE correlated well with serum Nt-proBNP levels and seems to be a useful variable to monitor the left ventricular stress and recovery during the various phases of surgery.

Increase in plasma free haemoglobin during cardiopulmonary bypass in heart valve surgery: assessment of renal dysfunction by RIFLE classification

Heart valve surgery carries a high risk of renal insufficiency as an independent risk factor due to prolonged cardiopulmonary bypass. Multiple causes of cardiopulmonary bypass-associated renal damage have been described, and haemoglobin-induced renal injury is presently being investigated. Forty-three patients scheduled for heart valve surgery (mostly combined) were enrolled in the prospective study. Plasma free haemoglobin (PFH) levels were evaluated by photocolorimetric measurement at the start of procedures (t(0)) and before the end of extracorporeal circulation (t(1)). A statistically significant increase in PFH levels during cardiopulmonary bypass was detected [median values (interquartile range) - t(0): 62.0 (53.4) mg/L, t(1): 320.4 (352.2) mg/L], P < 0.001. A significant regression relationship between the duration of cardiopulmonary bypass and the increased PFH was found (Spearman's correlation coefficient 0.628, P < 0.001). In some elderly patients, the tendency towards a high release of PFH during cardiopulmonary bypass was more pronounced, but the overall association between age and PFH levels was of borderline significance (P = 0.077). The correlation between PFH and post-operative serum creatinine was low and non-significant, but the latter correlated highly with the pre-operative serum creatinine values (Spearman's correlation coefficient reached values of 0.6-0.7, P < 0.001). Patients were classified according to the Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal failure (RIFLE) classification for acute renal dysfunction during post-operative days 1 - 4; the influence of PFH levels at t(1) on the consequent RIFLE classification was not proven (P=0.648), but 4 patients in the Injury category had shown a higher median value of PFH (433.6 mg/L) in comparison with the others (29 patients with no acute renal dysfunction - 313.7 mg/L, 10 patients at Risk - 330.1 mg/L).

Alterations in plasma soluble vascular endothelial growth factor receptor-1 (sFlt-1) concentrations during coronary artery bypass graft surgery: relationships with post-operative complications

BackgroundPlasma concentrations of sFlt-1, the soluble form of the vascular endothelial growth factor receptor (VEGF), markedly increase during coronary artery bypass graft (CABG) surgery with extracorporeal circulation (ECC). We investigated if plasma sFlt-1 values might be related to the occurrence of surgical complications after CABG.MethodsPlasma samples were collected from the radial artery catheter before vascular cannulation and after opening the chest, at the end of ECC just before clamp release, after cross release, after weaning from ECC, at the 6th and 24th post-operative hour. Thirty one patients were investigated. The presence of cardiovascular, haematological and respiratory dysfunctions was prospectively assessed. Plasma sFlt-1 levels were measured with commercially ELISA kits.ResultsAmong the 31 investigated patients, 15 had uneventful surgery. Patients with and without complications had similar pre-operative plasma sFlt-1 levels. Lowered plasma sFlt-1 levels were observed at the end of ECC in patients with haematological (p = 0.001, ANOVA) or cardiovascular (p = 0.006) impairments, but not with respiratory ones (p = 0.053), as compared to patients with uneventful surgery.ConclusionThese results identify an association between specific post-CABG complication and the lower release of sFlt-1 during ECC. sFlt-1-induced VEGF neutralisation might, thus, be beneficial to reduce the development of post-operative adverse effects after CABG.

Monitoring of oxidative and metabolic stress during cardiac surgery by means of breath biomarkers: an observational study

BackgroundVolatile breath biomarkers provide a non-invasive window to observe physiological and pathological processes in the body. This study was intended to assess the impact of heart surgery with extracorporeal circulation (ECC) onto breath biomarker profiles. Special attention was attributed to oxidative or metabolic stress during surgery and extracorporeal circulation, which can cause organ damage and poor outcome.Methods24 patients undergoing cardiac surgery with extracorporeal circulation were enrolled into this observational study. Alveolar breath samples (10 mL) were taken after induction of anesthesia, after sternotomy, 5 min after end of ECC, and 30, 60, 90, 120 and 150 min after end of surgery. Alveolar gas samples were withdrawn from the circuit under visual control of expired CO2. Inspiratory samples were taken near the ventilator inlet. Volatile substances in breath were preconcentrated by means of solid phase micro extraction, separated by gas chromatography, detected and identified by mass spectrometry.ResultsMean exhaled concentrations of acetone, pentane and isoprene determined in this study were in accordance with results from the literature. Exhaled substance concentrations showed considerable inter-individual variation, and inspired pentane concentrations sometimes had the same order of magnitude than expired values. This is the reason why, concentrations were normalized by the values measured 120 min after surgery. Exhaled acetone concentrations increased slightly after sternotomy and markedly after end of ECC. Exhaled acetone concentrations exhibited positive correlation to serum C-reactive protein concentrations and to serum troponine-T concentrations. Exhaled pentane concentrations increased markedly after sternotomy and dropped below initial values after ECC. Breath pentane concentrations showed correlations with serum creatinine (CK) levels. Patients with an elevated CK-MB (myocardial&brain)/CK ratio had also high concentrations of pentane in exhaled air. Exhaled isoprene concentrations raised significantly after sternotomy and decreased to initial levels at 30 min after end of ECC. Exhaled isoprene concentrations showed a correlation with cardiac output.ConclusionOxidative and metabolic stress during cardiac surgery could be assessed continuously and non-invasively by means of breath analysis. Correlations between breath acetone profiles and clinical conditions underline the potential of breath biomarker monitoring for diagnostics and timely initiation of life saving therapy.

Performance at 10 years of the CarboMedics ‘Top-Hat’ valve. Postclamping time is a predictor of mortality

The CarboMedics "Top-Hat" supraannular prosthesis was designed to permit the implantation of a larger prosthesis. We evaluated the outcome at 10 years in patients with this prosthesis. Between June 1993 and May 2001, 269 patients (average age, 63.9 years) received a CarboMedics "Top-Hat" supraannular aortic prosthesis. Primary valve replacement was performed on 203 patients (75.5%) and repeat valve replacement on 66 (24.5%). The duration of myocardial ischemia was 70.2+/-31.4 min, cardiopulmonary bypass 96.1+/-48.3 min, and postclamping time (time between release of aortic clamp and the end of extracorporeal circulation) 22.1+/-41.3 min. The mean follow-up was 82.3+/-17.8 months. Follow-up was 97.6% complete. The hospital mortality was 5.9%. It was 1% when the duration of postclamping time was <15 min, 2.8% between 15 and 29 min, 13.2% between 30 and 44 min, and 26.9% >44 min. In the multivariate analysis, postclamping time, urgent surgery, and body mass index were statistically significant risk factors for hospital mortality. The late mortality was 17.1%. Cardiac-related mortality showed a linearized rate of 18.1% per 1000 patients-year. The Kaplan-Meier estimates for cardiac-related mortality was 75.0% at 10 years. Postclamping time, aortic valve gradient, age over 70 years, and BMI were statistically significant risk factors for cardiac-related late mortality. The incidence of paravalvular leak in the "Top-Hat" aortic prosthesis was 1.7% per 1000 patients-year. Using the CarboMedics supraannular prosthesis allows implantation of a larger prosthesis without increasing valve-related complications. Postclamping time appears as a strong predictor of both hospital mortality and late cardiac-related death.

Alterations in plasma angiogenic growth factor concentrations after coronary artery bypass graft surgery: relationships with post-operative complications.

To determine whether angiogenic growth factor levels are altered during and after cardiac surgery, plasma concentrations of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and transforming growth factor beta1 (TGFbeta1) were measured in 32 patients undergoing coronary artery bypass graft (CABG) surgery with extracorporeal circulation (ECC). EGF levels significantly decreased during ECC and remained low until the 24th post-operative hour with no difference between complicated and uncomplicated patients. TGFbeta1 and bFGF concentrations significantly increased at the end of ECC and after cross-clamp release, and returned to pre-operative values at the 6th post-operative hour suggesting that the source of these elevations are the lungs and heart. After cross-clamp release bFGF levels but not TGFbeta1 ones were higher in patients with respiratory impairments. VEGF values increased significantly at the 6th and 24th post-operative hours. At the 24th post-operative hour plasma VEGF levels were higher in patients with cardiovascular and hematological impairments. In conclusion, these results highlight that the angiogenic network is profoundly altered in patients undergoing cardiopulmonary bypass as previously demonstrated for lipidic, cytokine and haematopoietic growth factor ones and identify an association between specific post-CABG complications and systemic release of bFGF and VEGF.

Relação das pressões atriais com o peptídio natriurético atrial e seus efeitos na diurese e natriurese durante operação cardíaca com circulação extracorpórea

Objective: To study the variations of the atrial natriuretic peptide (ANP) introduced by extracorporeal circulation (ECC) during cardiac surgery, and to test the hypothesis that there is a correlation between the ANP plasma levels, right atrial pressure (RAP), left atrial pressure (LAP), diuresis and natriuresis. Method: Study of a cohort of 15 patients submitted to myocardial revascularization using ECC. The intervals of the observation times were: t 0 = 10 minutes before ECC (control value); t 1 = 10 minutes after total flow in ECC; t 2 =30 minutes into total flow in ECC; t 3 = end stage of ECC at a nasopharingeal temperature of 36o C; and t 4 = 30 minutes after ECC has ended. Results: The ANP, LAP and RAP values varied significantly (p<0.001). The ANP dropped from t 0 to t 1 (NS), and then rose progressively until t 4 (p<0.001). The LAP and RAP were reduced (p <0.001) between t 0 and t 1 , rising progressively until t 4 (p<0.001). The urinary Na + rose between t 0 and t 3 (p<0.001) with a drop at t 4 . The diuresis increased progressively at all times considered (p<0.001). A significant correlation was found between ANP and the diuresis volume at t 0 , correlation coefficient of 0.535 (p=0.040) and at the time equal to t 2 between ANP and RAP, a correlation coefficient of 0.590 (p=0.021). Conclusion: The ANP concentrations present variations during revascularization surgery with ECC, favoring the idea that they are related to atrial pressures and, at the end of ECC, they have an important function in sodium excretion and the volume of diuresis.

Neuron-specific enolase increases in plasma during and immediately after extracorporeal circulation

Background. Minor cerebral complications are common after cardiac surgery. Several biochemical markers for brain injury are under research; one of these is neuron-specific enolase (NSE). The purpose of this study was to investigate the release of this enzyme into the blood during and immediately after extracorporeal circulation and to evaluate the effect of hemolysis on this release.Methods. Sixteen patients scheduled for elective heart surgery were included in the study. Blood samples for analysis of NSE and free hemoglobin in plasma were drawn before, during, and up to 48 hours after the end of extracorporeal circulation. The release of NSE from erythrocytes and its correlation to the release of free hemoglobin was studied by serial dilution and hemolysis in vitro.Results. The peri- and postoperative course was uneventful in all patients. Extracorporeal circulation initiated a release of NSE that reached a maximum 6 hours after the end of perfusion. Thereafter, the levels declined with an estimated t1/2 of 30 hours. The concentration of free hemoglobin increased during the perfusion, with maximum levels at the end of perfusion, after which they fell rapidly to normal values. The in vitro study showed a strong linearity between the release of NSE and free hemoglobin after induced hemolysis.Conclusions. The increased levels of enolase at the end of cardiopulmonary bypass can, to a major part, be explained by the release from hemolysed erythrocytes. The value of NSE as a marker for brain injury in these situations is therefore doubtful.

Recovery from lymphocytopenia following extracorporeal circulation: simple indicator to assess surgical stress.

This study investigated whether the lymphocyte count is a useful indicator to assess surgical damage following extracorporeal bypass. In Study 1, to investigate the correlation between extracorporeal circulating time (ECCT) and lymphocyte counts, 40 elective CABG patients were studied retrospectively. The lymphocyte recovery ratio (LRR), which represented the actual lymphocyte count divided by the preoperative lymphocyte count, was determined preoperatively, and on postoperative day (POD) 1, POD 3, and POD 5. In Study 2, the correlation between the interleukin-8 (IL-8) level and LRR was examined prospectively in elective CABG patients (n = 20). We measured the LRR and serum IL-8 levels preoperatively and during extracorporeal circulation (ECC) at 5 min, at the end of ECC, and 1, 3, and 12 h following ECC termination. Study 1 showed that the LRR decreased until POD 1 and gradually increased thereafter. The LRR had a negative correlation with the ECCT. In Study 2, the IL-8 level demonstrated a time course opposite to that of the LRR; it increased until 3 h after ECC termination and declined thereafter. There was a significant negative correlation between the LRR on POD 3 and the IL-8 level at 3 h after ECC termination. In summary, long-term ECC induced significant and prolonged lymphocytopenia. The LRR had a negative correlation with IL-8. These results indicated that the LRR may represent the degree of surgical stress following ECC; therefore, the counting of lymphocytes can be a quite useful bedside monitor to assess surgical damage and prognosis.

Significance of Serum S100 Release After Coronary Artery Bypass Grafting

Background. S100 protein has been suggested to be a serum marker for cerebral complications after cardiac operation and extracorporeal circulation. The aim of this study was to characterize the S100 release pattern after extracorporeal circulation in 515 consecutive patients undergoing coronary artery bypass grafting. Methods. Clinical variables and outcome were prospectively registered. The cerebral outcome was determined by clinical examination. S100 was measured at the end of extracorporeal circulation, and after 5, 15, and 48 hours. Results. After operation, 13 patients had stroke, 12 had delayed awakening, and 17 had encephalopathy. Early S100 release, immediately after extracorporeal circulation, was associated with age and perfusion time, but not with cerebral outcome. However, S100 release after 5 to 48 hours was associated with cerebral complications and risk factors for such outcome. Patients with stroke had higher S100 levels after 15 to 48 hours. A subset of patients with renal failure had overall higher S100 levels at 5 hours. Conclusions. Early and late S100 release indicate different mechanisms for release and emphasizes the potential power of this new biochemical marker for cerebral damage.

Comparison of Clinical Outcome Between Histidine-Triptophan-Ketoglutalate Solution and Cold Blood Cardioplegic Solution in Mitral Valve Replacement

This study was conducted to compare the effect of histidine-triptophan-ketoglutalate solution (HTK) with that of cold blood cardioplegic solution (CBC) in mitral valve surgery. Forty-six patients who underwent mitral valve replacement between January 1994 and December 1996 were enrolled in this study. Twenty patients received HTK (HTK group), while 27 patients had CBC (CBC group) as myocardial protection. HTK was given as a single high dose, whereas CBC was used in the usual multidose format. The doses of inotropic agent at the end of extracorporeal circulation did not differ between the HTK group and the CBC group. Creatine kinase values (units) on day 1 and day 2 were 1140+/-412, 921+/-436 for the HTK group and 904+/-335, 816+/-420 for the CBC group, respectively (p = NS). Spontaneous defibrillation occurred in 26% of the CBC group and 90% of the HTK group (p < 0.05). Pacing was temporarily used in 20% of the HTK group and 44% of the CBC group after extracorporeal circulation (p < 0.05). These results suggest that HTK provided more adequate myocardial protection in mitral valve surgery.

Cytokine and lipid mediator blood concentrations after coronary artery surgery.

This study investigates whether increased levels of cytokines and lipid mediators may be associated with complications after coronary artery bypass grafting (CABG) with extracorporeal circulation (ECC). Hemodynamic measurements and blood samples were obtained in 32 patients before and after the end of ECC and at the 6th and the 24th postoperative hours. Coagulation and pulmonary and cardiovascular functions were specifically assessed postoperatively at the same time. Patients with cardiovascular dysfunction had higher interleukin 8 (IL-8) levels. Higher platelet-activating factor (PAF) and decreased PAF acetylhydrolase activity (AHA, the enzyme that inactivates PAF) levels were found in patients with moderate cardiovascular dysfunction. Interleukin 6 (IL-6), IL-8, and AHA levels correlated with most hemodynamic parameters and creatine phosphokinase myocardial band levels obtained after surgery. Patients with severe lung injury had lower PAF, 6-keto prostaglandin (Pg)F1alpha, and PgE2 levels and higher thromboxane (Tx) B2 concentrations compared with patients without lung injury. Increased IL6 levels were only associated with moderate lung injury. Impaired hemostasis was associated with higher IL6 levels. AHA, IL-6, and IL-8 seem to be associated with cardiovascular dysfunction. The IL-6 blood levels and the ratio of TxB2/6 keto-PgF1alpha blood levels are increased during post-CABG lung injury. These results identify an association between specific post-CABG complications and the systemic inflammatory response. The clinical significance of this association remains to be evaluated. Patients with pulmonary, cardiovascular, or hemostasis dysfunction after cardiopulmonary bypass demonstrate aberrancies in a variety of cytokines and lipid mediators in arterial blood or plasma. The relationship between these findings and inflammatory response-induced complications remains to be determined.

Plasma macrophage colony‐stimulating factor levels during cardiopulmonary bypass with extracorporeal circulation

Leukocytosis and thrombocytopenia occur during cardiopulmonary bypass (CPB) with extracorporeal circulation (ECC). Elevated circulating concentrations of macrophage colony-stimulating factor (M-CSF) are reported during thrombocytopenia and leukopenia of different origins. We have assessed M-CSF concentrations in 40 patients undergoing CPB with ECC. Plasma M-CSF concentrations were stable during ECC and increased at the 6th (7.3 ± 0.7 IU/μg protein) and 24th (8.6 ± 0.8 IU/μg protein) postoperative hour compared with pre-ECC values (4.9 ± 0.5 IU/μg protein). A deep thrombocytopenia was found during ECC and until the 24th postoperative hour. A drop of leukocyte counts was found during ECC followed by an increase after ECC weaning. While no correlation was found between M-CSF concentrations and the leukocyte counts, M-CSF values were positively correlated with platelet counts only before and during ECC. Thus, M-CSF is not implicated in the thrombocytopenia and the leukopenia generated during CPB with ECC. However the elevated levels of M-CSFa few hours after the end of ECC might play a role in the inflammatory process often observed after CPB.

Continuous blood density measurements and volume changes during extracorporeal circulation in patients undergoing cardiac surgery.

The changes of blood volume and transcapillary fluid shifts during extracorporeal circulation (ECC) was examined using continuous measurements of blood density by the mechanical oscillator technique. Sixteen patients (1 female, 15 male) with a mean age of 61.4 years (+/- 7.6 years, 47-70 years) undergoing coronary artery bypass surgery were included in this study. The equipment for continuous measurement of the blood density (DPRT by Paar/Austria) was installed at the arterial line of the heart-lung bypass. Higher-precision discrete measurements of some parameters used the DMA 55 equipment produced by the Paar company. Measurements were taken at 37 degrees C. In 11 patients the transcapillary volume loss (difference of total volume between beginning and end of ECC) during heart-lung bypass (mean observation period of 55 min (+/- 16 min, 28-82 min) was found to be 870 ml/m2 body surface area (BSA) (+/- 360 ml, 290-1560 ml/m2) by the dilution method using the priming solution at the beginning and 500 ml lactated Ringer's solution added at the end of the ECC. The calculated volume shift using the "double density method", which takes into account blood density, plasma density, and hematocrit, amounted to 830 ml/m2 BSA (+/- 200 ml, 450-1210 ml/m2). The density of the transcapillary volume loss into the interstitial layer was calculated and found to be 1.0026 g/ml (+/- 0.0017 g/ml, 1.0003-1.0063 g/ml). A significant difference of transcapillary volume shift correlated with the administered catecholamine (dopamine, dobutamine) dosage postoperatively. Without catecholamine this difference was 260 ml/m2 BSA, with 3 microns/kg/min dopamine it rose to > 500 ml/m2 BSA.(ABSTRACT TRUNCATED AT 250 WORDS)