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Biomedical subjects

S Büket

Publications and source records attributed to S Büket.

At least 19 recordsLinked to original sources
PubMed2002

Reduction of spinal cord injury with pentobarbital and hypothermia in a rabbit model.

OBJECTIVES: to evaluate the effects of hypothermia and pentobarbital on spinal cord ischaemia induced in a rabbit model. MATERIALS AND METHODS: thirty-two rabbits, allocated into four equal groups, had the infrarenal aorta clamped distal to the left renal artery and above the iliac bifurcation for 40 min. Groups 3 and 4 had infusion of 15 mg/kg of pentobarbital intravenously for 5 min, 15 min before the cross-clamping. Groups 2 and 4 had infusion of 20 ml of Ringer's lactate (LR) solution at 3 degrees C for 3 min during aortic cross clamp into the isolated aortic segment. Group 1 was untreated and served as control. Postoperative functions of spinal cord were assessed. RESULTS: paraplegia occurred in all rabbits in Group 1, in one in each of Groups 2 and 3, whereas no paraplegia was observed in Group 4. In addition 2 and 3 animals of Groups 2 and 3, respectively revealed varying degree of neurological disturbances, whereas all animals of Group 4 had normal function. This difference between Groups 2, 3, and 4 vs Group 1 was significant (p<0.002). So was the difference between Groups 2 and 4 (p=0.03), whereas the difference between Groups 3 and 4 was not significant. CONCLUSIONS: hypothermia and pentobarbital was more effective than hypothermia alone for prevention of spinal cord ischaemia in a rabbit model.

Adjuvants, Anesthesia↗
PubMed2001

Circulatory arrest to protect transplant kidney in a patient with chronic type III dissection.

With broader indications for renal transplantation and improved allograft survival, it is anticipated that the problem of aortic disease in the post-transplant patient will be encountered with increasing frequency. We report a technique of protecting the transplant kidney from ischemic damage during distal aortic surgery. A 30-year-old renal transplant patient who had undergone an operation for ruptured chronic type III dissection 3 years previously underwent abdominal aortic aneurysm repair under hypothermic circulatory arrest. The patient recovered uneventfully and is presently doing well 1 year after the operation. Hypothermic circulatory arrest could be used in selected cases as a useful alternative for transplant kidney protection.

Adult↗
PubMed2001

An intraaortic solution trial to prevent spinal cord injury in a rabbit model.

OBJECTIVES: to evaluate the effectiveness of an intraaortic delivered solution on preventing spinal cord injury. DESIGN: forty rabbits were allocated into five equal groups. MATERIALS AND METHODS: one clamp was placed just distal to the left renal artery, and another was placed just above the iliac bifurcation for 40 min. Group 1 was not infused (control group). Through a 24G vascular catheter inserted into the isolated aortic segment, 20 ml of LR solution at room temperature (Group 2) 20 ml of LR solution at 3 degrees C (Group 3), and 20 ml of LR solution at 3 degrees C containing 30 mg/kg of methylprednisolone (Group 4) were infused over 3 min. In Group 5, 10 mg/kg of vitamins E and C were delivered two days before the experiment, and 20 ml of LR solution at 3 degrees C containing 30 mg/kg of methylprednisolone, and 10 mg/kg of vitamins E and C was infused at the operation. Postoperative spinal cord function was assessed using Tarlov's criteria. RESULTS: the neurologic status of Groups 3, 4, and 5 was significantly superior to that of Groups 1 and 2. No paraplegia was observed in Groups 4 and 5. Spastic paraplegia occurred in all rabbits of Groups 1 and 2, and in 20% of Group 3. In the electron microscopic evaluation of spinal cord specimens, normal histologic structure was observed in Groups 4 and 5, whereas, some derangements were observed in all others. CONCLUSIONS: intraaortic infusion of a hypothermic blended solution containing methylprednisolone, vitamins C and E provided best protection against postischaemic spinal cord dysfunction.

Animals↗
PubMed2001

Left ventricular diverticulum associated with Cantrell's syndrome and tetralogy of Fallot in an adult.

In this report we describe the surgical treatment of a 27-year-old patient with complete Cantrell's syndrome, i.e. multiple ventricular septal defect, left ventricular diverticulum, dextrorotation of the heart, an anterior diaphragmatic defect, and a midline supraumbilical abdominal wall defect with tetralogy of Fallot. Resection of the diverticulum was combined with correction of the tetralogy of Fallot and thoracoabdominal defects. The postoperative period was uncomplicated. We have have found only one previous report describing resection of the diverticulum combined with correction of Fallot's tetralogy and thoracoabdominal defects in an adult. One-stage repair of these complex anomalies is technically feasible and should be the treatment of choice.

Adult↗
PubMed2001

The side-effects of cardiopulmonary bypass on the lungs: changes in bronchoalveolar lavage fluids.

Although technical refinements have improved the safety of cardiac operations, postoperative dysfunction of lung and other organs occurs frequently after cardiopulmonary bypass (CPB). The aim of the present study was to search the aetiopathogenesis of pulmonary complications due to CBP. Ten patients with stable coronary artery disease, undergoing coronary artery bypass grafting (CABG) surgery, were included in the study. Forty bronchoalveolar lavage (BAL) fluid samplings were performed in the 10 patients. Samples were obtained at the following time periods: (1) preoperatively; (2) at the end of the first hour after anaesthetic induction; (3) at the conclusion of 30 min of crossclamp on CPB; and (4) at the conclusion of 20 h after the end of CPB, postoperatively. Cell contents of bronchoalveolar lavage fluid, alveolar macrophage viability, eosinophil cationic protein (ECP) levels and myeloperoxidase (MPO) concentrations were analysed in each bronchoalveolar lavage fluids. While the percentage of preoperative macrophages was 85.90% and the percentage of preoperative neutrophils was 2.40%, they were 77.00% and 11.30% in the postoperative samples, respectively. Mean alveolar macrophage viability was 96.20% preoperatively and 90.40% in the postoperative period. Preoperative eosinophil cationic protein mean concentration was < 2 microg/l and mean response value (RV) was 28.80. Preoperative mean myeloperoxidase concentration was 7.66 ng/ml. Postoperative eosinophil cationic protein mean response value was 63.40 and mean myeloperoxidase concentration was 59.25 ng/ml. There were significant differences between third and final samples with regard to both neutrophil percentages (p = 0.028) and MPO levels (p = 0.005). While the preoperative mean PaO2 value was 89.39 mmHg and mean SaO2 value was 97.12%, they were calculated in the postoperative arterial blood specimens of patients, without inhaling O2, as 65.31 mmHg and 93.84%. These changes between blood gas analyses reflect the impairment of the lungs (p = 0.009 and p = 0.007, respectively). Neither alveolar macrophage viability nor ECP levels changed significantly between consecutive periods. However, when the results of the first and fourth samples were compared, we saw the cumulative effects of CPB, in that alveolar macrophages lost their viability and ECP mean RVs rose. These changes were statistically significant (p = 0.027 and p = 0.013, respectively). However, postoperative ECP levels were not like those found in a patient with asthma. Also, changes between alveolar macrophage percentages (p = 0.028), between neutrophil percentages (p = 0.036) and between MPO concentrations (p = 0.005) were statistically significant. Again, changes in neutrophil percentages between first and final samples correlated with changes in MPO levels between same periods (r = 0.657, p = 0.039).

Adult↗
PubMed2001

Neurologic complications after deep hypothermic circulatory arrest: types, predictors, and timing.

To determine the nature of neurologic dysfunction after deep hypothermic circulatory arrest during aortic arch surgery, we reconsidered the cases of 154 patients who had undergone aortic arch surgery (either of the ascending or transverse aorta, or both) between November 1993 and July 1999. Temporary postoperative neurologic dysfunction was seen in 9 patients (5.8%), and another 3 patients (1.9%) experienced stroke. Patients with temporary neurologic dysfunction had no new infarct and were discharged home with no residual symptoms. Computed tomographic scans revealed that 2 patients with stroke had multiple infarcts in the brainstem, and the 3rd had bilateral border-zone infarcts. The patients with brainstem infarcts died on postoperative days 7 and 15, and the patient with border-zone infarct was discharged home with no symptoms 3 months after surgery. Univariate analysis revealed that patients with neurologic deficits had significantly higher rates of history of hypertension, concomitant coronary artery bypass grafting, cardiac ischemia times longer than 90 minutes, and chronic renal failure. A multivariate logistic regression analysis revealed that the significant preoperative variables associated with neurologic deficits were a history of hypertension and a cardiac ischemia time longer than 90 minutes. Deep hypothermic circulatory arrest is a safe and useful technique for protection of the brain during surgery for complex aortic problems. In future, some patients at extreme risk for perioperative neurologic complications might be offered novel neuroprotective agents, in combination with deep hypothermia.

Adult↗
PubMed2001

Regional lidocaine infusion reduces postischemic spinal cord injury in rabbits.

Paraplegia secondary to spinal cord ischemia is a devastating complication in operations on the descending and thoracoabdominal aorta. We hypothesized that the tolerance of the spinal cord to an ischemic insult could be improved by means of regional administration of lidocaine. Thirty-one New Zealand white rabbits were anesthetized and spinal cord ischemia was induced by the placement of clamps both below the left renal vein and above the aortic bifurcation. The animals were divided into 5 groups. Aortic occlusion time was 20 minutes in Group 1 and 30 minutes in all other groups. Groups 1 and 2 functioned as controls. Lidocaine (Group 5) or normal saline solution (Group 3) was infused into the isolated aortic segment after cross-clamping. Group 4 animals received 20% mannitol regionally, before and after reperfusion. Postoperatively, rabbits were classified as either neurologically normal or injured (paralyzed or paretic). Among controls, 20 minutes of aortic occlusion did not produce any neurologic deficit (Group 1: 0/4 injured), while 30 minutes of occlusion resulted in more consistent injury (Group 2: 6/8 injured). Animals that received normal saline (Group 3) or mannitol (Group 4) regionally showed 80% neurologic injury (4/5). Animals treated with the regional lidocaine infusion (Group 5) showed much better neurologic outcomes (7/9 normal: 78%). This superiority of Group 5 over Groups 2, 3, and 4 was significant (P <0.02). We conclude that regional administration of lidocaine reduced neurologic injury secondary to spinal cord ischemia and reperfusion after aortic occlusion in the rabbit model.

Anesthesia, Conduction↗
PubMed2001

Desmopressin usage in elective cardiac surgery.

BACKGROUND: Desmopressin acetate (DDAVP) has been implicated as a promising agent to reduce blood loss in patients undergoing cardiopulmonary bypass. METHODS: The effects of intraoperative desmopressin were studied in 66 patients undergoing coronary artery bypass grafting, randomized equally into desmopressin and control groups. The desmopressin group received 0.3 microg/kg desmopressin at the end of cardiopulmonary bypass. RESULTS: Fibrinogen level of both groups significantly reduced at postoperative 2nd hr, whereas a significant rise was observed at postoperative 24th hr with an intergroup difference favoring the control group (p=0.0307). In the desmopressin group, the activation time of factor VIII shortened during the whole postoperative period being significant (p=0.0127) at postoperative 24th hr. Postoperative von Willebrand factor (vWF) levels of the desmopressin group were significantly higher than the preoperative ones. The control group did not show such important changes in factor VIII and vWF measurements. Platelet aggregation times of both groups prolonged at postoperative 2nd hr. The control group showed significant elevation in ADP induced aggregation time at 2nd hr and significant reductions of platelet activation percentage in response to ADP, epinephrine, collagen and ristocetin at 2nd hr. Postoperative blood loss as well as blood transfusion need did not differ between the two groups. CONCLUSIONS: Despite the improved platelet functions, desmopressin does not seem to have obvious beneficial effects on postoperative hemostasis in patients without any bleeding disorder and undergoing elective cardiac surgery.

Blood Loss, Surgical↗
PubMed2000

The effects of modified hemofiltration on inflammatory mediators and cardiac performance in coronary artery bypass grafting.

Cardiopulmonary bypass increases the blood levels of various immune mediators, thereby leading to a systemic inflammatory response syndrome, e.g. sepsis, with some hemodynamic alterations, such as vasodilatation, tachycardia, and a decrease in systemic vascular resistance. Perioperative hemofiltration is one of the treatment modalities proposed to prevent this syndrome. Modified hemofiltration has been introduced recently by investigators who recommend that the former standard techniques are ineffective in eliminating the inflammatory mediators. The purpose of this study was to determine the effects of the modified technique on these mediators and on hemodynamic parameters. Forty patients undergoing coronary artery bypass grafting were randomized into equal control and hemofiltered groups. The hemodynamic parameters, as well as blood samples, were taken before and after hemofiltration to assess blood concentrations of interleukin-6, interleukin-8 and neopterin. The hemodynamic parameters and immune mediator levels did not differ between the two groups during the course of the study, except in the immediate postoperative periods, where cardiac output, cardiac index, and systemic vascular resistance values were significantly greater in the hemofiltered group while there were no differences in the immune mediators. The results of our study suggest that the effects of modified hemofiltration on immune mediators are still debatable. The improvement found in cardiac performance could be attributed to the prevention of hemodilution and hypervolemia.

Acute-Phase Reaction↗
PubMed1999

Cardiac surgery with cardiopulmonary bypass in patients with chronic renal failure.

OBJECTIVE: Renal failure is known to increase the morbidity and mortality in patients undergoing cardiac surgery. The results of heart surgery in patients with non-dialysis-dependent, mild renal insufficiency are not clear. METHODS: One hundred nineteen adult patients with chronic renal failure underwent cardiac surgery. Group I consisted of 93 patients who had creatinine levels between 1.6 and 2.5 mg/dL but who were not supported by dialysis. Group II consisted of 18 patients with creatinine levels higher than 2.5 mg/dL who were not supported by dialysis. Group III consisted of 8 patients with end-stage renal disease who were receiving hemodialysis. RESULTS: The hospital mortality rates were 11.8%, 33.0%, and 12.5%, respectively. Morbidity was 21.5%, 44.4%, and 75.0%, respectively, in groups I, II, and III. Postoperative hemodialysis was needed in 2 (2.15%) patients from group I and 6 (33%) patients from group II. On multivariable logistic regression analysis, risk factors for mortality were preoperative creatinine level more than 2.5 mg/dL, angina class III-IV, emergency operation, excessive mediastinal hemorrhage, postoperative pulmonary insufficiency, low cardiac output, and rhythm disturbances. Risk factors for morbidity were preoperative creatinine level more than 2.5 mg/dL and postoperative dialysis. CONCLUSIONS: Chronic renal failure increases the mortality and morbidity in patients undergoing cardiac surgery. Renal insufficiency with creatinine levels higher than 2.5 mg/dL increases the risk of postoperative dialysis and prolongs the length of hospital stay. Careful preoperative management and intraoperative techniques, such as avoiding low perfusion pressure and using low-dose dopamine, may be useful for a good operative outcome.

Adult↗
PubMed1999

Diagnosis and treatment of concomitant aortic and coronary disease: a retrospective study and brief review.

Coronary arteriosclerosis seriously complicates the surgical treatment of aortic diseases. The aim of our retrospective study was to determine the incidence of coronary artery disease among our surgical patients in treatment for aortic dissection or aneurysm, and to determine whether coronary intervention before aortic surgery appears to affect outcomes. Between 1 January 1993 and 1 March 1998, our center treated 253 patients for aortic dissection or aneurysm. We examined these cases retrospectively for information on diagnostic and treatment methods, both for the aortic lesions and for concomitant coronary arteriosclerosis. Aortic dissection had been detected in 86 (33.9%) patients and aortic aneurysm in 167 (66.1%). Coronary angiography was performed to search for concomitant coronary artery disease in 29 (33.8%) patients with dissection and in 112 (67.1%) patients with aneurysm; of these, 11 (12. 7%) and 54 (32.3%), respectively, were found to have coronary disease. Among 43 patients with abdominal aortic aneurysm in whom coronary angiography was performed, concomitant coronary disease was detected in 36 (83.7%). Coronary artery bypass surgery was performed in 10 patients who had dissection and in 30 patients who had aneurysm; percutaneous transluminal coronary angioplasty was performed in 7 patients who had aneurysm. Perioperative mortality rates in the dissection and aneurysm groups, overall, were 23.2% and 13.8%, respectively Unfortunately, the prospective, random clinical study that would be necessary to prove the case for or against preoperative coronary angiography among subsets of patients in need of aortic repair would raise ethical questions, given the strength of the information already in our possession, gathered by less formal methods. Our study reinforces existing evidence that preoperative angiography can reduce mortality and morbidity in the elective repair of aortic aneurysm, especially thoracic or abdominal aneurysm. However, angiography should not be performed routinely in cases of aortic dissection and should be withheld in cases of type A dissection.

Adolescent↗
PubMed1999

Proximal clamping levels in abdominal aortic aneurysm surgery.

In the surgical treatment of abdominal aortic aneurysm, the single proximal cross-clamp can be placed at 3 alternative aortic levels: infrarenal, hiatal, and thoracic. We performed this retrospective study to evaluate the advantages and disadvantages of the 3 main aortic clamping locations. Eighty patients presented at our institution with abdominal aortic aneurysms from March 1993 through May 1998. Fifty of these patients had intact aneurysms and underwent elective surgery, and 30 had ruptured aneurysms that necessitated emergency surgery. Proximal aortic clamping was applied at the infrarenal level in 24 patients (22 from the intact aneurysm group, 2 from the ruptured group), at the hiatal level in 34 patients (22 intact, 12 ruptured), and at the thoracic level (descending aorta) via a limited left lateral thoracotomy in 22 patients (6 intact, 16 ruptured). Early mortality rates (within 30 days) were 4% (2 of 50 patients) among patients with intact aneurysms and 40% (12 of 30 patients) among those with ruptured aneurysms. In the 2 patients from the intact aneurysm group, proximal aortic clamps were applied at the hiatal level. In the ruptured aneurysm group, proximal aortic clamps were placed at the thoracic level in 10 patients, the infrarenal level in 1, and the hiatal level in 1. According to our study, the clinical status of the patient and the degree of operative urgency--as determined by the extent of the aneurysm--generally dictate the proximal clamp location. Patients who present with aneurysmal rupture or hypovolemic shock benefit from thoracic clamping, because it restores the blood pressure and allows time to replace the volume deficit. Infrarenal placement is advantageous in patients with intact aneurysms if there is sufficient space for the clamp between the renal arteries and the aortic aneurysm. In patients with juxtarenal aneurysms, hiatal clamping enables safe and easy anastomosis to the healthy aorta. Clamping at this level also helps prevent late anastomotic aneurysm formation, which is frequently encountered after inadvertent anastomosis of the graft to a diseased portion of the aorta. Further studies are needed in order to confirm these results.

Adult↗
PubMed1998

Effects of flow types in cardiopulmonary bypass on gastric intramucosal pH.

The aim of this study was to determine the relationship between splanchnic perfusion and oxygen consumption, and flow types in cardiopulmonary bypass (CPB), by measuring gastric intramucosal pH. Twenty patients undergoing elective open-heart surgery were prospectively randomized to receive either pulsatile or nonpulsatile flow during CPB. Gastric intramucosal pH was measured using gastric tonometry. A flowmeter was used to measure the inferior caval vein flow. A catheter was inserted through the femoral vein to sample blood from the iliac vein. Systemic vascular resistance index, gastric intramucosal pH, inferior caval vein flow and arterial, inferior vena caval and iliac venous blood gases were recorded at different times. Gastric intramucosal pH decreased in all patients; only in the nonpulsatile group was this decrease statistically significant. After 45 min of CPB, the pH was 7.37 +/- 0.03 compared with the prebypass value of 7.48 +/- 0.04 (p = 0.00016). After weaning from CPB, the pH was 7.358 +/- 0.02 compared with the prebypass value (p = 0.000037). At 2 h post-operatively the pH was 7.416 +/- 0.025 (p = 0.02). Systemic vascular resistance index rose in all patients during bypass in both groups. These changes did not have any statistical significances and after weaning from bypass returned to prebypass levels. We conclude that nonpulsatile flow in CPB is associated with reduced gastric intramucosal pH and the measurement of intramucosal pH during open-heart surgery provides important information about splanchnic perfusion.

Adult↗
PubMed1998

Aortopulmonary artery fistula. Presenting with congestive heart failure in a patient with aortic dissection.

Although it is a rare occurrence, aortic dissections can rupture into the cardiac chambers or great vessels. A review of the English literature revealed only 3 cases of fistula between an aortic false lumen and the main pulmonary artery that were repaired successfully. In this article, we report the case of a chronic type I aortic dissection with an aortopulmonary artery fistula. The patient presented with congestive heart failure. One year earlier he had undergone aortic valve replacement. To our knowledge, this is the 4th case of a successfully repaired type I aortic dissection with rupture into the pulmonary artery and the 1st such case involving a patient who had undergone a previous cardiac operation.

Aged↗
PubMed1996

Complement consumption during cardiopulmonary bypass: comparison of Duraflo II heparin-coated and uncoated circuits in fully heparinized patients.

Heparin attachment to synthetic surfaces is one means of improving the biocompatibility of clinically used cardiopulmonary bypass (CPB) circuits. To assess the effect of heparin-coated circuits on complement consumption during CPB, 40 patients undergoing elective myocardial revascularization were prospectively randomized either to a group in which a completely Duraflo II heparin-coated circuit was used for perfusion (heparin-coated Group, n = 20 patients) or to a control group (n = 20 patients) in which an uncoated, but otherwise standard circuit was used. Full systemic heparinization was induced (activated clotting time, 480 seconds) in all the patients included in the study, regardless of which perfusion circuit was used. The two groups did not differ significantly in terms of bodyweight, aortic crossclamp and extracorporeal circulation times. No patient had difficulty in weaning from bypass and the postoperative period was uneventful in all patients. Concentrations of C3 and C4 were found to be within the "normal' range in the prebypass period in both groups. There were no significant intergroup differences with regard to C3 and C4 consumption during CPB. We conclude that Duraflo II heparin-coated circuits have no effect in reducing complement consumption during CPB in fully heparinized patients.

Adult↗
PubMed1995

Aortic arch operation: current treatment and results.

Between January 13, 1987, and December 31, 1993, 227 patients were treated surgically for aortic disease involving the transverse aortic arch. Forty-eight patients (21.14%) had acute aortic dissection (group A), 69 (30.40%) had chronic dissection (group B), and 110 (48.46%) had nondissecting fusiform or saccular aneurysms (group C). The replacement of the transverse arch involved 194 graft replacements, 27 elephant trunk procedures, and 6 patch graft repairs. Concomitantly, 22 patients had aortic valve resuspension, 18 patients had composite valve graft insertions, and 75 had separate aortic valve replacement. The frequency of prior cardiac operation was 20.83% (10 patients) in group A, 69.57% (48 patients) in group B, and 15.45% (17 patients) in group C. Profound hypothermic circulatory arrest was used in all patients during their transverse arch procedures. The mean circulatory arrest times (in minutes) were 29.18 +/- 1.39, 36.62 +/- 1.91, and 29.25 +/- 1.46 for groups A, B, and C, respectively. Retrograde cerebral perfusion through the superior vena cava cannula was used in 111 (48.9%) patients during the circulatory arrest period. In-hospital mortality was 6.17% (14 deaths). Long-term follow-up was 100% complete. There were 20 late deaths, with a long-term mortality rate of 9.26% (20/216).

Adult↗