Coagulation factor XIII reduces postoperative bleeding after coronary surgery with extracorporeal circulation.

BACKGROUND: One cause of diffuse bleeding after cardiac operations may be a low plasma concentration of coagulation Factor XIII, which is essential for coagulation but is not covered by standard coagulation monitoring. PATIENTS AND METHODS: In a prospective, randomized, double blinded study, 2500 units, 1250 units, and a placebo were administered in groups of 25 patients each, immediately after administration of protamine. Postoperative amount of blood loss and blood transfusion was recorded. RESULTS: Patients were not statistically different with respect to the course of plasma levels of Factor XIII until administration of the study drug. In all groups Factor XIII fell from preoperative normal values to subnormal values after extracorporeal circulation. After administration of the study drug, Factor XIII increased to 71 %, 85 %, 103 % in the placebo, 1250 units, and 2500 units group, respectively, and these differences were statistically significant ( p < 0.05). Postoperative blood loss was lowest in the 2500 units group and highest in the placebo group, however this was not significantly different. There was also no significant difference in the amount of blood transfusion. After differentiating all patients according to their post medication Factor XIII level into two groups with levels of < 70 % and > or = 70 %, postoperative blood loss was found to be significantly higher in the < 70 % group as was the amount of blood transfusions. CONCLUSIONS: Factor XIII administration reduces postoperative blood loss and the extent of blood transfusion after coronary surgery, however administration is only helpful if plasma levels are below the normal value. Measurement of plasma levels is recommended before Factor XIII substitution.

The CardioOP-Data Clas (CDC). Development and application of a thesaurus for content management and multi-user teleteaching in cardiac surgery.

OBJECTIVES: Self-directed and customized medical education programs are gaining importance in health care instruction. We prototypically implemented a repository-driven online computer system (CardioOP) for teleteaching in Heart Surgery. It supports authoring and multiple re-use of multimedia data for different user groups in different instructional applications and therefore requires a process of content management. METHODS: We defined objectives for a terminological system to support semantic, cross-media type annotation and retrieval of learning objects: domain completeness, German (natural) language processing, multi-user concepts, extensibility and maintenance, content based annotation and technical implementation. Existing terminologies (ICD10, READ V3, Snomed III, UMLS 1997, MESH) have been analysed according to these objectives. RESULTS: We found that the analysed terminologies did not meet our criteria sufficiently. Therefore, we developed a domain-specific thesaurus, the CardioOP-DataClas (CDC). The application of the CDC within a database-driven authoring process using specifically developed tools is reported. CONCLUSIONS: Metadata play an important role in the effective discovery and search, access, integration and management of educational multimedia data in medicine but so far, there is no terminology to support content management for instructional multimedia. We prototypically designed and applied a thesaurus for the CardioOP educational system. Additional work is needed to evaluate the system in terms of user-friend-liness, concept coverage and information retrieval performance.

Accuracy of beat-to-beat cardiac output monitoring by pulse contour analysis in hemodynamical unstable patients.

BACKGROUND: Continuous determination of cardiac output (CO) by transpulmonary thermodilution calibrated pulse-contour analysis is gaining clinicical acceptance. However there is doubt, whether this method is reliable in hemodynamic instable patients. We compared pulse-contour analysis to thermodilution in patients with profound changes of CO. MATERIAL AND METHODS: 24 patients were investigated. CO was measured by thransthoracic thermodilution and pulse-contour analysis in intervals of 60 min during study periods of 8-44 h without recalibration of the pulse-contour computer. Results of 517 measurements were compared by regression, structural regression and Bland-Altman analyses. RESULTS: Mean change of CO was 40 +/- 27% (range 20-139%), range of systemic vascular resistance was 450 dyn x s/cm(-5) - 2360 dyn x s/cm(-5). Correlation of pulse-contour analysis CO to thermodilution CO was r=0.88 with p=0.0001, bias was 0.2 l/min with 1.2 l/min standard deviation. Mean CO by pulse-contour analysis did not differ significantly from CO by thermodilution during the study period. There were no influences of heart rate or arterial pressure on the difference between both methods. CONCLUSIONS: CO measurement by arterial pulse-contour analysis is reliable even in patients with profound changes of CO or during hemodynamic instability.

Less invasive, continuous hemodynamic monitoring during minimally invasive coronary surgery.

BACKGROUND: Minimally invasive coronary surgery has gained more and more clinical acceptance. A clear contrast to the minimally invasive idea is the highly invasive pulmonary artery catheter used for hemodynamic monitoring during the operation. We evaluated a less invasive device which calculates cardiac output (CO) and hemodynamics based on arterial pulse-contour analysis. METHODS: In 20 patients revascularized by the off-pump technique with the octopus system, agreement of CO by pulse-contour was compared to pulmonary arterial and femoral arterial thermodilution and hemodynamic alterations during the operation were recorded. Pulse-contour CO is computed by measuring the area under the arterial pressure waveform and dividing it by aortic impedance. Aortic impedance is determined by an arterial thermodilution at the onset of the system. RESULTS: Correlation of pulmonary arterial and arterial thermodilution CO to pulse-contour CO was 0.91 and 0.90 respectively (both p<0.01). Coefficients of variations were 6.2% and 6.7%. The bias was 0.1 L per minute and standard deviations were 0.42 L per minute and 0.55 L per minute. Hemodynamic changes during the operations were seen mainly during the distal anastomosis of the first diagonal branch; only slight changes occurred during the anastomosis of the left anterior descending coronary artery. CONCLUSIONS: Arterial pulse-contour analysis is easy to use and minimally invasive, thus qualifies as a reliable routine monitoring tool during minimally invasive coronary surgery with tissue stabilizers.

Surgical versus medical care for postoperative cardiac surgical patients at the general ward.

OBJECTIVES: To shorten hospital stay after cardiac surgery, several risk factors have been defined to identify patients who can be discharged early. These risk factors are dependant on the patient; no studies exist on the influence of the treating physician himself on postoperative patient stay. METHODS: In a university affiliated cardiac surgical clinic we investigated patients who were postoperatively treated either on medical wards with no cardiac surgeon's presence or on a cardiac surgical ward; at both types of wards physicians had several years experience with cardiac surgical patients. Taking several risk factors for postoperative morbidity into account, postoperative length of stay and incidence of wound healing complications have been compared. RESULTS: Within a 3-month period, 84 patients were treated at the cardiac surgical ward, 102 patients at the medical wards. Risk factors for postoperative morbidity were present in 87% of patients, statistically independent of postoperative wards. Although demographic data and median ICU-stay of both patient groups was comparable, the median post-ICU stay was 9 days at the surgical and 13 days at the medical wards (P < 0.0001). Incidence of wound healing complication was higher (19.6%) at the medical wards than at the surgical ward (10.7%), without reaching statistical significance. CONCLUSION: As patients at the respective wards were statistically not different, the difference in post-ICU stay, infection and costs must depend on the treating physicians. As a consequence, postoperative care for cardiac surgical patients in all cases should include direct cardiac surgical participation.

Concept of and preliminary trial protocol for adjuvant treatment of mediastinitis with immunoglobulins after cardiac surgery (ATMI): response to comments and criticism.

During the consensus-based process of protocol development external experts were invited to comment on a proposal for a trial protocol on adjuvant immunotreatment of patients with wound infection after median sternotomy (ATMI). Controversies and arguments can be divided into five main areas: 1) rationale and objectives; 2) criteria for patient selection; 3) adjuvant treatment; 4) measures of efficacy; and 5) course and timetable of the study. We present and summarise the experts comments and criticism as well as the result of the final discussion of the study group with respect to these areas.

Continuous, less invasive, hemodynamic monitoring in intensive care after cardiac surgery.

A pulse-contour-based method for continuous measurement of cardiac output (CO) and systemic vascular resistance (SVR) was tested and arterial thermodilution, used for calibration, was compared to pulmonary artery thermodilution. In 30 patients CO and SVR were measured by pulse contour analysis (COpc, SVRpc) 270 times in 24 h and compared to arterial (COart, SVRart) and pulmonary arterial (COpa, SVRpa) thermodilution measurements. The mean difference between COpa and COart was 0.26 L/min (3.6%) with a standard deviation (SD) of 0.7 L/min, the correlation coefficient was 0.96, and the coefficient of variation was 5.0% and 5.9% respectively. COpc did differ from COpa by 0.11 L/min (1.5%, SD = 0.6 L/min) and from COart by 0.15 L/min (2.1%, SD = 0.7 L/min). Correlation of COpc with COpa was 0.91, correlation of COpc with COart was 0.90. SVRpc did correlate with SVRpa, a coefficient of 0.94, and with SVRart, a coefficient of 0.92. Mean COpc and SVRpc did not differ significantly from COpa or COart and SVRpa or SVRart during the 24 h study period. It is concluded that COart correlates well with COpa and can be used to calibrate COpc. COpc and SVRpc agree with thermodilution-based CO and SVR without recalibration for 24 hours.

Procalcitonin as a marker of systemic inflammation after conventional or minimally invasive coronary artery bypass grafting.

Cardiac surgery using cardiopulmonary bypass (CPB) often induces a systemic inflammatory response syndrome (SIRS). The concept of minimally invasive direct coronary artery bypass (MIDCAB) eliminates cardiopulmonary bypass. We evaluated the perioperative time course of procalcitonin (PCT) to compare the inflammatory response due to these two different surgical procedures. 57 patients were studied: CABG with CPB (n = 30), MIDCAB without CPB (n = 27). The following data were measured preoperatively, after induction of anesthesia, after separation from CPB in the CABG group or after left internal mammary artery (LIMA)-to-left anterior descending artery (LAD) anastomosis in MIDCAB group, and every 3 hours for the first 42 hours in the ICU: PCT, C-reactive protein (CRP), body temperature, hemodynamic parameters, and the need for catecholamines. Leucocyte counts were measured daily. For statistical analyses the Friedmann, Wilcoxon, or Mann-Whitney U tests were used. PCT in the CABG group rose to a maximum of 2.0 ng/ml (median) at 15 hrs postoperatively. In the MIDCAB group maximal PCT concentration was 0.7ng/ml (median) (p < 0.05). CRP was elevated to 17.1 mg/dl in the CABG and 18.5mg/dl in the MIDCAB group (n.s.). The leucocyte counts were increased on day 2 in the CABG group (p < 0.05). In the CABG group about 25% of the patients needed noradrenaline, but in the MIDCAB group none (p < 0.05). Body temperature did not differ between both groups. The increase in PCT concentration was more pronounced after CABG, indicating a reduced inflammatory response after MIDCAB. CRP was increased after both procedures. PCT reflects the inflammatory response after cardiac bypass surgery with or without CPB.

Central venous pressure, pulmonary capillary wedge pressure and intrathoracic blood volumes as preload indicators in cardiac surgery patients.

OBJECTIVE: Monitoring of cardiac preload is mainly performed by measurement of central venous and pulmonary capillary wedge pressure in combination with assessment of cardiac output, applying the pulmonary arterial thermal dilution technique. However, the filling pressures are negatively influenced by mechanical ventilation and the pulmonary artery catheter is criticized because of its inherent risks. Measurement of right atria, right ventricular, global end diastolic and intrathoracic blood volume index by arterial thermal dye dilution utilizing the COLD-system may represent an alternative. METHODS: In 30 CABG patients with an uncomplicated postoperative course the mentioned parameters were measured 1, 3, 6, 12 and 24 h postoperatively to prove their qualification as preload indicators: As patients received no inotropic support, changes of cardiac index and stroke volume index must correlate to changes of presumably preload indicating parameters. RESULTS: When arterial and pulmonary arterial thermal dilution were compared, no differences were found; the correlation coefficient being 0.96, the bias 0.16 l/min per m2 (2.4%) and coefficients of variation did not exceed 7%. Changes of central venous pressure, capillary wedge pressure, right atrial end diastolic volume index and right ventricular end diastolic volume index did not correlate at all to changes of cardiac and stroke volume index (coefficients ranged from -0.01 to 0.28). In contrast, intrathoracic and global end diastolic blood volume indices with coefficients from 0.76 to 0.87, did show a good correlation to cardiac and stroke volume index. CONCLUSION: Central venous pressure, capillary wedge pressure, right atrial and right ventricular end diastolic volumes are no suitable preload parameters in cardiac surgery intensive care, compared to intrathoracic and global end diastolic blood volumes. The latter show a higher clinical value and can be obtained by less invasive methods, as no pulmonary artery catheter is required.

Reproducibility of double indicator dilution measurements of intrathoracic blood volume compartments, extravascular lung water, and liver function.

STUDY OBJECTIVE: Arterial thermal dye dilution (TDDart) with the COLD system (Munich, Germany) allows measurement of cardiac index (CI), partial blood volumes, lung water, and liver function. The aim of the study was to determine agreement of TDDart measurements with pulmonary artery thermal dilution measurements (TDpa) and to assess the reproducibility of TDDart parameters. DESIGN: Prospective study. SETTING: ICU of a university hospital department of cardiac surgery. PATIENTS: Thirty consecutive patients after coronary artery bypass grafting. MEASUREMENTS AND RESULTS: Triplicate measurements of TDDart parameters were performed 1, 3, 6, 12, and 24 h postoperatively and coefficients of variation (CVs) were computed. At the 3-h point, additional fivefold TDDart measurements were done and compared with TDpa measurements. The coefficient of correlation for CI from TDDart vs TDpa was 0.96 (p<0.001), and the mean difference was 0.16 L/min/m2 (2.4%). The CVs of the TDDart and TDpa CI measurement were 7.2% and 5.9%; the CVs of other TDDart parameters were 4.6% (cardiac function index), 8.3% (global end-diastolic volume), 7.0% (intrathoracic blood volume), 7.6% (total blood volume), 7.4% (right ventricular end-diastolic volume), 7.4% (right heart end-diastolic volume), 11.3% (left heart end-diastolic volume [LHEDV]), 12.0% (right to left heart volume proportion [R/LHV]), 8.8% (pulmonary blood volume), 10.8% (extravascular lung water), 16.4% (plasma disappearance rate of dye), and 19.8% (dye clearance). The CV did not depend on Glasgow coma scale or on body temperature. CONCLUSION: The CVs of LHEDV and R/LHV are influenced by asynchronous TDDart and TDpa variation. The CVs of plasma disappearance and dye clearance are increased as the half-life of the dye is longer than the measurement sequence. All other parameters derived from TDDart and TDpa show a clinically sufficient reproducibility.

Reduction of wound healing problems after median sternotomy by use of retention sutures.

Obese people have a higher risk of sternal wound dehiscence resulting from traction of suprasternal tissue. In such patients we recommend the use of retention sutures with extracorporeal plates to improve tissue connection and to disburden fascia and skin sutures. This augmented closure is simple and effective and, since 1996, has prevented wound healing problems in more than 50 patients with a body mass index greater than 27.

The effect of factor XIII on bleeding in coronary surgery.

BACKGROUND: One cause of diffuse bleeding after cardiac operations may be a low plasma concentration of Factor XIII, which is essential for coagulation, but is not covered by standard coagulation monitoring. METHODS: In a prospective pilot study, Factor XIII levels before and after extracorporeal circulation were investigated, and drain volumes and blood transfusions of a control group of 11 patients were compared with a group of 11 patients who received 2500 units Factor XIII postoperatively. RESULTS: Factor XIII fell significantly from preoperative values of 96.1% and 88.7% (control) to 55.7% and 51.8% (control) postoperatively. By administration of Factor XIII, plasma level rose significantly from 55.7% to 103.1%; in the control group the value remained low. Drain volumes on the first and second postoperative day were significantly lower in the Factor XIII group. In the control group 1.9 units of red blood cells and 1.6 units fresh frozen plasma were administered, in the Factor XIII group 0.9 and 0.6 units were necessary. CONCLUSIONS: Factor XIII influences bleeding after coronary surgery and can reduce the need for blood transfusions. In patients with prolonged diffuse bleeding, we therefore recommend substitution of Factor XIII.

Platelet morphology in patients with mechanical circulatory support.

OBJECTIVE: Mechanical circulatory support is a therapy for patients with end stage cardiac insufficiency. The thromboembolic events are feared complications during support, due to the surface thrombogenicity of the implanted device. Activated blood platelets play a major role in this context. Consequently the platelet morphology of patients was investigated. METHODS: Platelets of eight patients were observed by means of scanning electron microscopy during the period of support with the Novacor left ventricular assist system N100. Blood was collected preoperatively and daily during the first week as well as weekly during the first 3 months. Samples were fixed with cacodylic-acid buffered glutaraldehyde. Platelet alterations were classified as non-activated, activated and aggregated, based on the so-called 'shape change' morphology. In addition, blood coagulation parameters were evaluated (e.g. activated partial thromboplastin time, prothrombin time, antithrombin III). RESULTS: Preoperatively, 15.0 +/- 4.6% (overall mean values) of activated platelets were found. Within the first postoperative week, the mean level of activated platelets increased to 32.8 +/- 8.0% (P < 0.05). Comparing short- (< 30 days; n = 4) vs. long-period (> 30 days; n = 4) support, a significant difference of activated platelets was evaluated (24.3 +/- 3.3% vs. 34.8 +/- 3.4%, P = 0.004). A correlation was found between the values of activated clotting time and activated platelets. Specific platelet deformations and damages appeared during support, which could not be found preoperatively. CONCLUSIONS: The platelet morphology showed alterations in all patients probably most strongly induced by the surface activation of the implanted device. These observations should be taken into consideration in management of postoperative anticoagulation therapy.

Thirty-year results of Starr-Edwards prostheses in the aortic and mitral position.

BACKGROUND: Between 1963 and 1977 a total of 415 patients admitted to the University Hospital Munich underwent an isolated valve replacement with a Starr-Edwards prosthesis in the aortic or mitral position. METHODS: A retrospective follow-up of 87.1% of the patients representing 4,254 patient-years was completed. Surviving patients were examined by means of echocardiography. RESULTS: Survival rates after 10, 20, and 30 years were 62.3%, 39.4%, and 19.9% after aortic valve replacement and 75%, 36.5%, and 22.6% after mitral valve replacement (operative mortality excluded). Freedom from all valve-related complications, reoperations, and valve-related death was 66.4%, 43.3%, and 23.8% after aortic valve replacement and 73.4%, 35.4%, and 14.3% after mitral valve replacement. Of the surviving patients, 82% and 76% who received aortic or mitral valves, respectively, are in New York Heart Association class I or II. The pressure gradients of the aortic valves were between 20 and 73 mm Hg; those of the mitral valves were between 9 and 30 mm Hg. Fifty-two percent of aortic and 68% of mitral valves show no echocardiographic peculiarities. The left ventricular function in both groups is normal in 64%. CONCLUSIONS: The long-term results together with the echocardiographic results show that after 30 years the Starr-Edwards valve represents a standard that still needs to be achieved by newer prostheses.

Thirty years survival after double valve replacement with Starr-Edwards prostheses in aortic and mitral position.

We report about a patient who underwent double valve replacement with two Starr-Edwards prostheses in aortic and mitral position 30 years ago. Under anticoagulation medication he survived 28 years without any valve-related events. In the 29th year he sustained a cerebral infarction from which he recovered, having only a residual left arm paresis. His NYHA functional class today is II-III. Chest X-ray shows a mildly enlarged configuration of the heart, echocardiography reveals no irregularities of the implanted prostheses. We conclude, that the Starr-Edwards valve presents an outstanding standard concerning durability in mechanical valve replacement.

[On-site laboratory monitoring on the intensive care unit. Blood gas, electrolyte, glucose, hemoglobin and lactate determination with the CIBA Corning 865 Analysis System]. / Stationsbezogenes Labor-Monitoring auf der Intensivstation. Blutgas-, Elektrolyt-, Glucose-, Hämoglobin- und Lactat-Bestimmungen mit dem CIBA-Corning 865 Analyse-System.

INTRODUCTION: For decision-making in the ICU, rapid and accurate analysis of vital laboratory parameters is essential. The industry provides devices which analyse these parameters on a decentralised setting and which are designed for use by non-laboratory personnel. We investigated whether accuracy and handling of a new analyser (Ciba-Corning 865, Chiron Diagnostics, Medfield, USA) are good enough for basing clinical decisions on the measured parameters. MATERIALS AND METHODS: The Ciba-Corning 865 allows measurement of blood gases, electrolytes, haemoglobin, glucose and lactate by use of photometric, ion-selective, enzymatic and electrochemical sensors in less than 18 microliters of whole blood. In a cardiac surgical intensive-care unit the accuracy of the device was tested by comparison to 61 measurements of quality control reagents, 48 tonometered blood samples and 536 parallel measurements in the clinical laboratory. Besides a 10-minute instruction, the participating personnel had no formal training with the device. RESULTS: The differences between measurements in quality control reagents and tonometered blood and the expected value were lower than 5%. The comparison with clinical laboratory measurements showed correlation coefficients from 0.94 (sodium) to 0.99 (glucose, lactate). The biases in Bland-Altman analyses were below 5%, the limits of agreement were found to be in a clinically acceptable range for all parameters. During the test period no technical problems occurred with the analyser and good acceptance by the personnel was found. CONCLUSIONS: The measured parameters were accurate enough to be used for therapeutic decisions in acute care medicine. Although it should not be a complete alternative to the clinical laboratory, because of rapid analyses, small sample volumes and easy handling the use of the Ciba-Corning 865 is advantageous for patients and users.

25 years follow-up of patients after replacement of the aortic valve with a Smeloff-Cutter prosthesis.

Thirty years ago the Smeloff-Cutter double-caged ball prosthesis was developed for aortic valve replacement. Between 1967 and 1977 a total of 46 patients admitted to the University Hospital Munich underwent an isolated aortic valve replacement with the Smeloff-Cutter prosthesis. Postoperatively all patients received anticoagulation treatment with phenprocoumon (Marcumar). A retrospective follow-up of 95.6% of patients, representing 842 patient years, was completed. The corresponding actuarial survival rates after 10, 20, and 25 years were 69.1%, 47.4%, and 31.4%. The actuarial freedom rates from either valve-related complications, reoperations, or death were 72.9%, 47.4%, and 20.3%. Thromboembolism occurred in 1.41% per patient year, bleeding in 1.90%. The rates of valvular dysfunction, reoperation, and endocarditis were 1.16%, 1.16%, and 0.2% per patient-year. Today, of the surviving patients 81% are in NYHA Class I or II, 19% in NYHA Class III. No surviving patient deteriorated over the reported time in his or her functional NYHA classification. After 25 years the Smeloff-Cutter valve has proved to be a reliable prosthesis for aortic valve replacement and-together with the Starr-Edwards prosthesis-it has set a standard in longterm durability by which all other valve designs will have to be measured.