Direct oxymetric peripheral tissue perfusion monitoring during open heart surgery with the use of cardiopulmonary bypass: preliminary experience.

BACKGROUND: Regional hypoperfusion has been associated with the development of postoperative organ dysfunction in cardiac surgery involving cardiopulmonary bypass (CPB). Direct tissue oxymetry is a potentially new method for monitoring the quality of the peripheral tissue perfusion during CPB. The aim of this study was to assess the effects of CPB in skeletal muscle oxygenation when measured in the deltoid muscle by direct oxymetry during perioperative period. METHOD: Seven patients underwent on-pump coronary artery bypass grafting. Direct oxymetry was performed by an optical cathether introduced into the deltoid muscle. Continuous measurement was made during the surgical procedure and the postoperative period. Mean arterial blood pressure, blood flow during CPB, laboratory markers of tissue hypoperfusion, blood gases and body temperature were also recorded. RESULTS: Interstitial muscle tissue oxygen tension (pO(2)) decreased after the introduction to anaesthesia and, more significantly, during CPB. After the disconnection from CPB at the end of the operation, the pO(2) returned to pre-anaesthetic values. During the first hours after admission of the patients to the intensive care unit, the pO(2) progressively decreased, reached a minimum value after four hours, and increased slowly thereafter. There was a significant correlation of pO(2) with mean arterial blood pressure and blood flow during that time. CONCLUSION: The result of this first measurement seems to demonstrate that the standard technique of conducting cardiopulmonary bypass produces low muscle oxygen tension and, thus, little perfusion of skeletal muscle. The data also indicate that both high mean arterial blood pressure and high flow are necessary during CPB to ensure skeletal muscle perfusion. The investigation is continuing.

[The effect of preoperative administration of heparin on the heparin resistance development]. / Vliv predoperacního podání heparinu na vznik heparinové rezistence.

BACKGROUND: Heparin resistance is relatively frequent problem in cardio surgery. We were try to determine real occurrence heparin resistance before operation. AIM OF THE STUDY: Purpose of the project--to find the real frequency of heparin resistance in patients who will undergo a cardio surgical operation. To find out the dependence between the pre-operational application of heparin and the development of heparin resistance. METHODS: We recorded pre-operative administration heparin in patients. If the dose of heparin was 5 mg/kg and more then we insert patients to the group heparin resistant. RESULTS: In our collection was heparin resistance in 203 patients from 624, it was 32.5%. Test agreement relative frequency with 22% was throw out--p < 0.001--heparin resistance in our group statistically different from 22% heparin resistance was higher than hypothesis. Heparin before operation was administrate 181 patients, which make to 29%. For administration of heparin was hypothesis of independence thrown (p < 0.001). CONCLUSION: Results of our works confirmed statistically significant occurrence of heparin resistance in patients that was administration heparin pre-operative. Heparin resistance occurred against presumption 22% in 32.5% in our group. It is statistic significant difference.

Scintigraphic detection of experimental myocardial infarction with 99mTc-heparin in the dog.

Experimental infarctions were produced in 12 dogs by ligation of the Ramus interventricularis anterior of the left coronary artery, and their uptake of 99mTc-heparin was measured 7, 24 and 48 h as well as 7 days thereafter by recording an in vivo chest scintigram 4 h after intravenous injection of the compound. The dogs were subsequently killed, the heart removed and an in vitro scintigram obtained. Finally, the uptake of the compound was measured in tissue samples. The results indicate that 99mTc-heparin is accumulated in lesions which are not older than 24 h. At the other points in time uptake is low but even 24-h old lesions cannot be demonstrated reliably. The results are impaired by the high blood activity on the cardiac chambers and by the background activity of the lungs. In general, 99mTc-heparin has less useful properties than the more frequently employed 99mTc-pyrophosphate so that a change of procedure is not to be recommended.

The pyrophosphate heart scintigram in children with progressive muscular dystrophy.

A pyrophosphate heart scintigram was obtained in 16 boys with progressive muscular dystrophy Duchenne. All of them showed pathological ECG findings and high plasma levels of CK, AST, ALT and LD. In 4 patients the scintigram was distinctly positive and in further 3 it reached borderline values. The remaining 9 boys had normal scintigraphic findings. Those with a positive heart scintigram had very high plasma levels of the enzymes under study which was suggestive of current progression of the disease. There was, however, no relation between heart scintigraphy and the affliction of the skeletal muscles expressed by means of an index.

Scintigraphic myocardial imaging with 99mTc-labelled gluconate of experimentally produced cardiomyopathy in dogs.

In 10 dogs experimental cardiomyopathy was produced using high intravenous doses of adrenaline and theophylline. The possibility of scintigraphic detection of this non-ischaemic damage was tested by means of 99mTc-gluconate. In 5 dogs the scintigraphic examination was carried out 4 hrs following the production of the damage. In all 5 cases a marked positivity of the heart scan was observed. The finding was confirmed by the radioactivity of tissue samples from all sections of the heart. In 3 out of 5 dogs the histological examination of the myocardium (PAS and HBFP staining) was positive. In the remaining 5 dogs the scan was performed 24 hrs following the development of the damage. A positive scintigraphic finding was observed in 4 cases, the degree of accumulation being lower than at 4 hrs. The radioactivities of tissue samples were also significantly lower as compared with the 4-hr values. In contrast, the histological findings were markedly positive in all 5 dogs. It follows that 99mTc-gluconate is capable of detecting in addition to infarctions non-ischaemic damages to the myocardium, too. The normalization of the finding is very quick. This experimental finding appears to be of importance in clinical practice.

Scintigraphic detection of experimental myocardial infarction with 99mTc-2,3-dimercaptosuccinic acid.

Acute myocardial infarctions were produced by ligature of the left frontal descending coronary artery in 9 dogs. The possibility of scintigraphic imaging with 99mTc-DMSA 4 hrs after intravenous administration was studied. The infarctions were 4, 24 and 48 hrs old. The in vivo scan was positive in only one dog with a 4-hr old infarction. The in vivo scans were confirmed by the analysis of the radioactivity in tissue samples. The accumulation of the radiopharmaceutical increased slightly in 48-hr old lesions; however, this increase was not sufficient for a positive scintigraphic finding. Thus, we do not recommend 99mTc-DMSA for clinical use in acute lesions.

[Scintigraphic diagnosis of experimentally induced pericarditis in dogs using 99mTc-labelled pyrophosphate (author's transl)]. / Szintigraphische Diagnostik der experimentellen Perikarditis des Hundes mittels 99mTc-Pyrophosphat.

In the present paper the possibilities of scintigraphic diagnosis of experimental pericarditis are discussed. Pericarditis was induced by either talc or formaldehyde intrapericardially. In all animals the administration of talc as well as formaldehyde produced inflammatory changes which were more serious after formaldehyde. The scan of the talc pericarditis was carried out on the 7th day after operation and of the formaldehyde pericarditis on the 3rd, 7th or 14th days. No positive scintigraphic finding was made in any of the experimental animals, apart from a massive incorporation in the operation scars. The counting of radioactive impulses after the exstirpation of the tissue samples confirmed the scintigraphic findings. Statistical evaluation did not reveal any essential difference between the accumulation of the radiopharmaceutical into the pericarditis as well as into the pericardial bag in comparison with the control animals. Although our model does not exactly reflect the situation of patients suffering from pericarditis it may be assumed that pyrophosphate scintigraphy is not suitable for the diagnosis of acute pericarditis in clinical practice.

Scintigraphic myocardial imaging with 99mTC-labelled pyrophosphate of experimentally produced cardiomyopathy in dogs.

Scintigraphic examination of the myocardium using 99mTc-labelled pyrophosphate was carried out in 10 dogs with experimentally produced cardiomyopathy. This was brought about by intravenous administration of high doses of adrenalin and theophylline. The scan was positive in 8 out of 10 dogs. "Hot" foci were very extensive. The degree of accumulation was however low (2+). Histological examination of the myocardium using the light microscope showed only scarcely distinguishable damage to the tissue without the presence of necrosis. ECG examinations were normal in all cases. By means of 99mTc-labelled pyrophosphate even very small myocardial disorders can thus be detected. This fact may be of clinical importance for an early diagnosis of heart lesions.

Pyrophosphate scan of the temporarily ischemized dog myocardium.

In 9 dogs a transient myocardial ischemia was provoked using complete occlusion of the ramus interventricularis anterior of the left coronary artery. The occlusion was removed after 5, 10 or 15 min. Four hrs after removal of the occlusion a scan of the myocardium was carried out using 99mTc-labelled pyrophosphate. In 7 out of 9 dogs under study the scan was markedly positive, in 2 dogs negative. ECG demonstrated ischemic changes practically in all dogs; the changes became normal after removal of the occlusion, namely in 5 to 35 min. The histological examination of the tissue demonstrated in all 9 dogs only a slight impairment of the myocardium.

Pyrophosphate scintigraphy and other non-invasive methods in the detection of cardiac involvement in some systemic connective tissue diseases.

Thirteen patients with systemic lupus erythematosus, 8 patients with polymyositis, and 6 patients with spondylitis ankylopoetica (Bechterew's disease) underwent clinical cardiologic examination and scintigraphy of the myocardium (99mTc-pyrophosphate), ECG, echocardiography, polygraphy, and their blood pressure was taken. The aim of the study was to ascertain how such a combination of non-invasive examinations can help in recognizing a cardiac involvement. In systemic lupus erythematosus cases one or more positive findings were revealed in 9 patients (69%), in 4 patients all examinations were negative (31%). Four patients (50%) with polymyositis had positive findings. In patients with spondylitis ankylopoetica positive findings occurred in 2 cases (33%). The study has shown that a combination of non-invasive cardiologic methods increases the probability of detecting cardiac involvement in systemic connective tissue diseases.

A modified technique for the production of an arterio-venous shunt in sheep, allowing a comparison of biocompatibility of synthetic materials.

Polytetrafluorethylene (PTFE) prostheses were implanted in 12 sheep as a shunt between the carotid artery and the jugular vein using an end-to-side anastomosis technique. This technique allows repeated tests of the pharmacological and toxicological safety of artificial kidney units after both single and multiple administration. Furthermore, it enables the investigation of detoxification of compounds via dialysis, thus contributing to drug safety. Implantation of the prosthesis was uncomplicated. Connection to the extracorporeal circulation was achieved via catheters and maintained using a pump with an output of up to 300 ml/min. This enabled maintenance of extracorporeal circulation for several hours without clinical impairment to the animals. The AV-shunts remained functional for between 8 and 253 days (mean 112.3 days).

How long can the previously assembled cardiopulmonary bypass circuit stay sterile?

The sterility of previously assembled cardiopulmonary bypass circuits was investigated for 100 extracorporeal circuits. The closed circuits were assembled using aseptic technique and remained in the pump room until time of use. The mean time from point of setup to point of priming for the 100 consecutive circuits was 32 hours, with a range of 19 to 89 hours. Circuits were primed with the calculated volume of priming solution, circulated for 5 minutes and tested for microbial contamination by withdrawing 20 ml of the priming solution and 10 days incubated in Thioglycolate and Sabouraud culture mediums. All were found to be free of microbial contamination. The results of this investigation demonstrate that the sterility of the extracorporeal circuit, pre-assembled in advance of actual priming, can be maintained over an extended interval when standard aseptic technique is used. This allows the utilization of a pre-assembled circuit for emergency cardiopulmonary support.

Changes of the serum antibiotic levels during open heart surgery (ceftazidim, ciprofloxacin, clindamycin).

BACKGROUND: Wound, mediastinal and intracardiac infections are still very serious complications of open-heart surgery. The incidence of it is still in the range of 0.4%-5%. The aims of our study were to assess the adequacy of regimen using ceftazidim (CTZ), ciprofloxacin (CPF) and clindamycin (CLIN) as prophylactic antibiotics and to verify whether cardiopulmonary bypass (CPB) can modify the time of antibiotic serum concentrations. That is why the serum levels of them were measured during open heart procedures. METHODS: The prospective study comprised 75 consequent coronary patients randomized in to three groups receiving 1 g of CTZ or 400 mg of CPF or 900 mg of CLIN i.v. with anesthesia induction. Routine coronary surgery with left internal mammary artery harvesting, moderate body hypothermic (30 degrees C) CPB with crystaloid cardioplegia was performed. Serum antibiotic levels were determined before application, with skin incision, prior CPB induction, after cardioplegia infusion, every 20 minutes of CPB, prior end of CPB, in time of chest closure. Conventional cylinder-plate microbiological assay was used for antibiotic level measurement. RESULTS: All serum antibiotic concentrations showed a sharp decrease immediately after starting CPB and lasted until CPB ended. After initiating of CPB after cardioplegia administration serum concentrations of CTZ (105 min after initial dose) decreased by, on average 55%, CPF (97 min) by 42% and CLIN (116 min) by 78%. CONCLUSION: CPB can modify the time course of antibiotic serum concentrations. The serum levels of CTZ at the end of the longest procedures were found to be below the MICs for some of the suspected pathogens. We recommend to use higher antibiotic doses for prophylaxis and to administer the second dose with protamin sulphate to obtain maximum concentration in newly formed blood clots.

[Evaluation of statistical tables in surgery using a computer]. / Vyhodnocovanie statistickych tabuliek v chirurgii pocítacom.

The authors describe the possibility to use a computer in surgery for evaluation of classification tables of child injuries and the six-month report on the activity of policlinical and in-patient surgical departments. The solution of the problem was elaborated using system DOS-RV on a SM 4/20 computer.

[Surgical myocardial revascularization in a female patient with bilateral occlusion of the common carotid arteries]. / Chirurgická revaskularizace myokardu u nemocné s oboustranným uzáverem spolecných krkavic (kazuistika).

Concurrent stenosis of the coronary and carotid circulation is one of the most serious disease. The authors describe the case of a 74-year old female patient with ischaemic heart disease with concurrent bilateral occlusion of the common carotid arteries. Surgical revascularization of the myocardium was made using extracorporeal circulation under general normothermia with protection of the heart muscle from ischaemia by the method of warm blood cardioplegia. In the discussion the authors analyze contemporary possibilities of surgical treatment of ischaemic disease (MIDCAB, OPCAB, operations with extracorporeal circulation) and emphasize the advantages and risks of different procedures.

[Interstitial microdialysis study of changes in metabolism and blood flow in skeletal muscles during cardiac surgery with normothermic and hypothermic extracorporeal circulation]. / Sledování zmen metabolismu a krevního prutoku v kosterním svalu behem srdecní operace v mimotelním obehu v normotermii a hypotermii pomocí intersticiální mikrodialýzy.

AIM: Hypoperfusion of peripheral tissues and splanchnic organs during cardiac surgery in extracorporeal circulation may lead to the origin of serious complications. The aim of the study was to monitor metabolism and blood pressure in interstital peripheral tissue, skeletal muscle, during the operation on the patient with extracorporeal circulation (ECC) in an early post-operation period by means of microdialysis. METHODS: The interstitial microdialysis is a minimally invasive method for the biochemical monitoring of metabolic changes and blood pressure in extracellular space of tissue. The substances in interstitium pass across a semipermeable membrane of the inserted microdialysis probe and may be analyzed. Microdialysis in this study was performed by means of two microdialysis probes CMA (CMA Microdialysis AB, Sweden) inserted into the deltoid muscle of the surgically treated patient. The probes were perfused by the Ringer solution at the rate of 0.3 ml/hour. The dialysates were sampled in the following intervals: beginning of the operation, beginning of ECC, end of ECC, end of the operation, two hours during the post-operation period. Standard biochemical methods were to evaluate, in the dialysates, glucose, urea, glycerol and lactate. The blood flow in the interstitium was monitored by means of dynamic microdialysis of gentamycine as a marker. Microdialysis was performed in 40 patients with ischemic heart disease, operated on in the extracorporeal circulation. In 20 patients the ECC was performed in normothermia (NT), while in the other 20 patients it was made in hypothermia (HT). RESULTS: In both groups, NT versus HT, a similar dynamism of interstitial concentration of the observed substances in relation to the operation phase and in early post-operation period. Low initial concentrations were gradually increasing during the extracorporeal circulation and increased further after the end of extracorporeal circulation and also in the subsequent phase of the operation. The concentration values of the analytes under observation were higher in the groups operated on under normothermia, apparently due to normal cellular activity during normothermia (versus values in hypothermia). Immediately after the operation the observed values decreased in the both groups and subsequently gradually increased in the post-operation period in the both groups. The trend of dynamic changes of the observed analytes, selected as compounds indicating metabolic activity of skeletal muscles during hypothermia documents a lower metabolic activity of the cells during hypothermia and its marked increase (against NT) in the phase of subsequent normalization of the tissue temperature. Analysis of the concentrations of lactate, as a compounds mapping anaerobic metabolism of skeletal muscle, revealed similar dynamic changes in the both groups (NT vs. HT). There were no significant differences, related to the phase of the operation or the phase of immediate post-operation course when the both groups were compared. The analysis of gentamycine concentrations as a flow marker revealed lower gentamycine concentrations in dialysate during the operation, ECC and the early post-operation course in the group operated on in normotheramia (vs. HT), indicating a higher tissue flow in skeletal muscle against the group of patients operated on under hypothermia. CONCLUSION: The results of the microdialysis study demonstrated dynamic changes in interstitial concentrations of the observed compounds (glucose, urea, glycerol and lactate) related to the phase of operation on the heart in extracorporeal circulation and in early post-operation period. A higher perfusion of skeletal muscle was documented in patients operated on under normothermia. It became obvious that the dynamism in the changes of the compounds observed in the interstitium of skeletal muscle was determined by metabolic activity of the tissue as well as by blood flow in the muscle interstitium.

[The post-perfusion syndrome after operations performed with extracorporeal circulation]. / Postperfuzní syndrom po operaci v mimotelním obehu.

Postperfusion syndrome (PPS) is a dreaded complication of cardiac surgery operation in extracorporeal circulation (ECC). Four factors play a key role in its pathophysiology: 1. contact of blood with the material of ECC, 2. release of activated leucocytes from pulmonary bed after the release of aortic cross-clamp, 3. translocation of endotoxin due to gut ischemia and its consequent reperfusion, 4. activation of coagulation, fibrinolytic, kallikrein-kinin and complement systems. The occurrence of PPS can be limited by reducing the ECC time and/or cross-clamp time, by using membrane oxygenator in the system of ECC, by using polyester or polypropylene in the set of ECC, by using heparin-coated set or leucocyte filter in the system of ECC, by application of pharmacological dosis of corticosteroids prior to the ECC, by early enteral nutrition. In eligible patients it is possible to eliminate the risk of PPS completely by using the operation without ECC. The experience of the authors with above mentioned problems is given and confronted with literature.

[Kinetics of ceftazidime in prophylactic administration during cardiopulmonary bypass]. / Kinetika ceftazidimu pri profylaktické aplikaci u kardiopulmonálního bypassu.

Serum ceftazidime levels were followed in 21 patients in which routine coronary bypass surgery with cardiopulmonary bypass was performed. Each patient received one gram of ceftazidime intravenously with anesthesia induction. Antibiotic concentrations were estimated using the microbiologic assay diffusion plate method. The average operation time was 220 +/- 41 minutes (range 130-310). The start of cardiopulmonary bypass was 86 +/- 21 minutes and the full flow time was 104 +/- 21 minutes after starting of ceftazidime application. It can be stated that the decline of ceftazidime serum levels after starting of cardiopulmonary bypass was faster in comparison with standard serum curves of this antibiotic. The concentrations of ceftazidime at the end of some operations were under the supposed minimal inhibitory concentrations for some microorganisms possibly implicated. No infection was recorded.

Vapor diffusion-controlled meso crystallization of membrane proteins.

The presented method to crystallize membrane proteins combines the advantages of the meso-phase crystallization method and the classical vapor diffusion crystallization. It allows fast screening of crystallization conditions employing automated liquid handlers suited for the 96-well crystallization format.