Measurement of Bivalirudin Thrombin Inhibition Activity in Plasma with Clotting or Chromogenic Assays and Dedicated Calibrators and Controls

Bivalirudin is a parenteral direct thrombin inhibitor anticoagulant and does not induce any impairment of the Protein C pathway, which function remains preserved. This drug meets increasing applications for cardiac surgery and heart diseases, especially when heparin is contra-indicated in presence of heparin-induced thrombocytopenia. Major indications concern Extra Corporeal Circulation, PCI/PTCA, and myocardial infarction. Drug clearance occurs partly through kidney. Patients with moderate or severe renal dysfunctions are exposed to drug accumulation and subsequent bleeding, the major adverse effect reported. This study presents 2 automated assays, a clotting method, and a kinetics chromogenic technique, proposed for the quantitative measurement of bivalirudin in citrated plasma. Both assays need a specific bivalirudin calibration, are fully automatable on coagulation instruments, and can be available at any time in specialized clinical laboratories for an on time monitoring of treated patients. Assay ranges are from 0.3 to 5.0 μg/ml (clotting assay) or to 6.0μg/ml (chromogenic assay), and up to 20.0μg/ml with an additional automatic plasma dilution. These methods offer excellent performances, with good reproducibility and repeatability. This study reports the results obtained with both assays on bivalirudin measurements in 26 treated patients collected at 4 timings. Both methods are fully consistent and contribute to facilitate and secure the use of this anticoagulant when it is indicated.

Air, inflammation and biocompatibility of the extracorporeal circuits

The inflammatory response in cardiac surgery using extracorporeal circulation (ECC) has been widely discussed in the literature with analysis on cytokines released in humans; demonstrating manifold trigger causes. To mitigate this response—mainly linked to the contact and recognition by the blood of a “non-self” surface—many efforts have been made to make the circuits of the extra-corporeal circulation “biomimetics”; trying to emulate the cardio-vascular system. In other words, biomedical companies have developed many biocompatible products in order to reduce the invasiveness of the ECC. One of the techniques used to reduce the contact of blood with “nonself” surfaces is the “coating” of the internal surfaces of the ECC. This can be done with phospholipidic, electrically neutral, and heparin derivates with anticoagulant activity. The coating can be divided into two categories: the “passive coating” with Phosphorylcholine by biomedical companies and the administration of albumin added to the “priming” during the filling of the circuit by the perfusionist. Alternatively, we have the “active” coating: treatment of the internal surfaces in contact with the blood with neutral proteins and heparin. The latter are different according to the production company, but the aim is always to maintain high levels of systemic and local anticoagulation, inactivating the “contact” coagulation between the blood and the surfaces. A recent study demonstrates that the use of an “active coating” is associated with better preservation of the endothelial glycocalyx compared with “passive coating” circuits.

The development of oxygenators in extra corporeal circulation

The objective of this paper is to present one of the most important components of the extracorporeal circulation circuit, the oxygenator. In addition, the manufacture materials, the function and superiority of modern oxygenators are presented in order to stress their advantages over the older types. The future of oxygenators and the tendency to develop small intravascular artificial lungs are also discussed. A bibliographic study of the history and first reports of extracorporeal blood oxygenation has been performed in an attempt to describe the function of these initial oxygenators and to analyze the disadvantages which led to the development and to the exclusive of the membrane oxygenators. Since the establishment of the current knowledge that the artificial membrane of the modern oxygenators is the best material to oxygenate blood and remove carbon dioxide during extracorporeal circulation, further research concerning the oxygenator’s membrane was necessary to solve particular problems, such as plasma leak. Technologic advantages in the oxygenator’s membrane made possible the safe use of the oxygenator for 28 days in the extracorporeal membrane oxygenation (ECMO) circuits. The different materials used for the construction of the oxygenators are discussed with details. The incorporation in the oxygenator of additional devices, such as the heat exchanger, the arterial filter and blood reservoir to develop one compact construction is considered to be one more upgrade of the oxygenator’s technology. Accidents and safety precautions of the oxygenators are also discussed especially that of the thrombosis of the device. The necessity for more detailed and accurate monitoring of the oxygenator in real time during cardiac surgery is discussed. The latter holistic approach to the operation of the oxygenator and of the components which incorporate in the device offers specific advantages, while modification of the surface in contact with the blood ameliorates the inflammatory response.

Anesthesia for Off Pump Coronary Artery Bypass Surgery in a Patient with Brain Tumor

The outcome after off pump coronary artery bypass grafting (OPCAB) surgery has been promising. These good outcomes relate to the benefits of avoiding extra corporeal circulation. Some of the reported advantages include a lower incidence of renal complications, pulmonary complication, adverse neurological event, reduced transfusions requirement and attenuation of the systemic inflammatory response. If the patient has associated preoperative complicated neurological issues, then perioperative management will be more challenging and requires extensive care and precautions.We present a case with symptomatic meningioma and unstable angina who underwent successful urgent OPCAB surgery without further neurological deterioration.

Detection and decontamination of Mycobacterium chimaera and other non-tuberculosis mycobacteria in heater–cooler devices used in cardiopulmonary bypass: a Manufacturer and National guidelines summary, and a potential resolution to the problem requiring further investigation

Since 2011, invasive infections due to Mycobacterium chimaera have been diagnosed in patients with previous cardiac surgery. The use of heating/cooling devices (heater–cooler units), necessary to regulate the blood temperature in extra-corporeal circulation, has been identified as a source of contaminated aerosol. Adhering to a strict maintenance program according to the manufacturer’s instructions for use including sanitizing is essential to reduce the risk. Current manufacturer guidelines and national recommendations for detection and decontamination of Mycobacterium chimaera and other non-tuberculosis mycobacteria should organically update units’ policies and protocols as they are published.

Kirurško zdravljenje raka pljuč z razširjeno levo pnevmonektomijo in resekcijo dela prsne aorte pri bolnici z masivno hemoptizo – Prikaz primera

Severe airway bleeding or massive hemoptysis is a rare condition that carries high mortality. Patients are at risk of life-thretening respiratory compromise due to the airways filling with blood. The main principles in the management of massive hemoptysis are: maintainance of airway patency, localization of the source of bleeding and control of the hemorrhage. Most cases of massive hemoptysis are caused by inflammatory lung diseases such as aspergiloma, tuberculosis and bronchiectasis while a severe bleeding from a malignant lung tumor is a rare find.We present a case of massive hemoptysis in a 60-year old woman, caused by the invasion of lung cancer into the left pulmonary trunk and aorta, which was successfully managed by an extended left pneumonectomy, with the resection of the proximal part of the descending thoracic aorta and interposition of a vascualar graft without extra corporeal circulation. A complete (R0) resection was also achieved.