Biomedical subjects

M Turina

Publications and source records attributed to M Turina.

580 records · Page 33Linked to original sources

PubMedDate not supplied

Coagulation patterns in bovine left heart bypass with phospholipid versus heparin surface coating.

The current study was designed to evaluate tubing sets with either polymeric phospholipids or ionically bound heparin in six bovine experiments (body weight, 70 +/- 5 kg). No heparin was given systemically. Left heart bypass was started with 300 ml of clear priming solution and maintained over 6 hours (50 ml/kg/min). Coagulation studies included platelet counts, activated coagulation time (ACT), thrombin time (TT), fibrinogen (Factor I), antithrombin III (AT III), and fibrinopeptide A (FPA). Normalized platelet levels dropped from 100 +/- 12% before to 86 +/- 13% after 6 hours of left heart bypass for heparin, compared with 100 +/- 46% to 90 +/- 44% for phospholipid coating (NS). The ACT increased from 146 +/- 7 sec at 10 min to 159 +/- 16 sec after 6 hours for heparin, compared with 122 +/- 4 to 126 +/- 5 sec for phospholipid (p < 0.05). Thrombin time changed from 18 +/- 0 sec before to 19 +/- 1 sec after 6 hours for heparin, as compared with 16 +/- 1 sec to 18 +/- 1 sec for phospholipid (NS). Factor I levels decreased from 1.5 +/- 0.3 g/L to 1.3 +/- 0.1 g/L for heparin, compared with 1.5 +/- 0.2 g/L to 1.4 +/- 0.3 g/L for phospholipid. Antithrombin III levels changed from 102 +/- 26% to 91 +/- 7% for heparin, compared with 123 +/- 12% to 118 +/- 12% for phospholipid. Fibrinopeptide A levels changed from 100 +/- 60% to 130 +/- 13% for heparin, compared with 100 +/- 11% to 99 +/- 6% for phospholipid (P < 0.05). No macroscopic red clots were found in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Intravascular oxygenation. Influence of the host vessel diameter on oxygen transfer.

An extra corporeal venovenous bypass circuit (right atrium to pulmonary artery), including an intravascular gas exchanger in a blood chamber with a variable inner diameter, was developed for ex vivo evaluation of the host vessel diameter/intravascular oxygen transfer relationship. Three host vessel diameters mimicking different configurations of the caval axis were studied in three bovine experiments (body weight 82 +/- 3 kg). Blood flow was 3,000 ml/min and device oxygen inflow was 2,300 ml/min. Serial blood samples were taken for 26 mm, 23 mm, and 20 mm inner blood chamber diameters after hemodynamic stabilization before and after exposure of the circulating blood to the intravascular gas exchanger (sampling ports at blood chamber inlet and outlet). Measured oxygen saturation at the blood chamber inlet was 25.0 +/- 11.7% for the 26 mm diameter as compared to 31.7 +/- 12.6% for 23 mm, and 28.7 +/- 9.2% for 20 mm. At the outlet, the corresponding O2 saturations were 34.5 +/- 11.5% for 26 mm, 42.9 +/- 8.8% for 23 mm, and 43.2 +/- 6.2 for 20 mm. Total O2 transfer was 24.9 +/- 11.5 ml/min for 26 mm, 31.9 +/- 7.4 ml/min for 23 mm, and 35.9 +/- 12.2 ml/min for 20 mm (p < 0.05). Likewise, O2 transfer rate was 8.3 +/- 3.8 ml/L, 10.6 +/- 2.4 ml/L, and 12.0 +/- 4.0 ml/L (p < 0.05). Parallel analyses of total CO2 transfer and CO2 transfer rates provided less consistent findings. At 3 L/min, the pressure drop between the inlet and outlet of the blood chamber was 12 +/- 3 mmHg for 26 mm, 26 +/- 1 mmHg for 23 mm, and 38 +/- 2 mmHg for 20 mm diameters (p < 0.001). The authors conclude that oxygen transfer of a given intravascular gas exchanger appears to be indirectly proportional to the host vessel diameter. Increasing blood pressure gradient as a function of decreasing diameter has to be considered in clinical application.

Animals↗

PubMedDate not supplied

Diagnosis and management of blunt great vessel trauma.

Traditionally, thoracic aortic rupture, suspected after blunt thoracic trauma, is characterized by a chest radiograph showing a widened mediastinum. The diagnostic machinery consecutively activated still depends heavily on the pressure as additional traumatic lesions. A patient with additional cranio-cerebral trauma would typically undergo contrast-enhanced computed tomography or magnetic resonance imaging of head, chest, and other regions. In a number of patients these analyses would confirm the presence of blood in the mediastinum without formal proof of an aortic disruption. This is because mediastinal hematomas may be caused not only by an aortic rupture, but also by numerous other blood sources including fractures of the spine and other macro- and microvascular lesions providing similar images. Therefore, aortic angiography became our preferred diagnostic tool to identify or rule out acute traumatic lesions of not only the aorta but with great vessels. However recently, a number of traumatic aortic transsections have been identified by transoesophageal echocardiography (TEE). TEE has the additional advantage of being a bed-side procedure providing additional information about cardiac function. The latter analysis allows for identification and quantification of cardiac contusions, post-traumatic myocardial infarctions, and valvar lesions which are of prime importance to develop an adequate surgical strategy and to assess the risk of the numerous emergency procedures required in patients with polytrauma. The standard approach for repair of isthmic aortic rupture is through a lateral thoracotomy. Distal and proximal control of the aorta can be achieved in a substantial number of cases before complete aortic rupture occurs and a higher proportion of direct suture repair can be achieved under such circumstances. Most proximal descending aortic procedures are performed without cardiopulmonary bypass (clamp and go) but paraplegia may occur before, during, or after the procedure. Ascending aortic lesions and disruption of the aortic arch, the supra-aortic vessels, the main pulmonary arteries, the great veins as well as cardiac lesions are best approached through a sternotomy, which may have to be extended. Cardiopulmonary bypass allowing for deep hypothermia and circulatory arrest is often required and carries its own complications. It is not clear whether the increasing proportion of ascending aortic and cardiac lesions which are observed nowadays are due to a change in trauma mechanics (i.e., speed limits, seat belts, air-bags), an improvement of the diagnostic tools or both.

Aorta, Thoracic↗

PubMedDate not supplied

The infected aorta.

BACKGROUND: Despite the improvements achieved in antibiotic therapy, severe aortic infection resulting in mycotic aneurysms is still a highly lethal disease and surgical management remains a challenging task. PATIENTS AND METHODS: A total of 43 patients with severe aortic infections were analyzed and separated in four groups: (1) Infections of the aortic root Ventriculo-aortic disconnection due to deep aortic infection (6 patients). Two patients were operated using homo-composit grafts. Of the 6 patients total, one died early and two died late during a mean follow-up of 6 years. The two patients with homografts are still alive. (2) Infections of the ascending aorta and the aortic arch. In situ repair for mycotic aneurysmal lesions of the ascending aorta was performed in 6 patients using synthetic graft material in 4/6, biological material in 1/6 and direct suture in 1/6. Two patients had to be reoperated; one of them died early. There was no recurrent infection during a mean follow-up of 6 years. (3) Infections of the descending thoracic and thoraco-abdominal aorta in-situ repair for mycotic aneurysmal lesions of the descending and thoraco-abdominal aorta was performed in 12 patients using homografts in five. Two patients died early and two other patients died late during a mean follow-up of 6 years. (4) Infections of the infrarenal abdominal aorta. In this series of 19 patients with mycotic infrarenal aortic aneurysms, in situ reconstruction was performed in 12 (5/12 with homografts) and extra-anatomic reconstruction (axillo-femoral bypass) was performed in 7. Hospital mortality was 5/19 patients and another 5/19 patients died during a mean follow-up of 6 years. One of the early deaths was due to aortic stump rupture. Two patients with axillo-femoral reconstructions were later converted to descending-thoracic-aortic-bifemoral bypasses. Five thromboses of axillo-femoral bypasses were observed in three of the seven patients with extra-anatomic repairs. RESULTS: Infections of the aortic root, the ascending aorta and the aortic arch are approached with total cardio-pulmonary bypass, using cardioplegic myocardial protection and deep hypothermia with circulatory arrest if necessary. Proximal unloading and distal support using partial cardiopulmonary bypass is preferred for repair of infected descending and thoracoabdominal aortic lesions, whereas no such adjuncts are required for repair of infected infrarenal aortic lesions. CONCLUSIONS: The anatomical location of the aortic infection and the availability of homologous graft material are the main factors determining the surgical strategy.

Aneurysm, Infected↗