Multimodal, Biomaterial-Focused Anticoagulation via Superlow Fouling Zwitterionic Functional Groups Coupled with Anti-Platelet Nitric Oxide Release

The functions of anti-fouling, zwitterionic polycarboxybetaine (pCB) and anti-platelet nitric oxide (NO) release replicate key anticoagulant properties of the endothelium. The two approaches, only tested separately thus far, were paired on gas permeable polydimethylsiloxane (PDMS) membranes and evaluated for anti-coagulation. Uncoated PDMS (control) and PDMS coated with pCB were screened for fibrinogen (Fg) fouling followed by platelet adsorption testing to evaluate the effects of coating and/or NO using bioreactors. Bare or coated PDMS membranes separated sheep plasma (108 platelets/ml) and gas flow chambers within the bioreactors. Either 100 or 0 ppm of NO/N2 flowed through the gas chamber for NO release at the plasma/biomaterial interface. Surface-adsorbed platelets were quantified using a lactate dehydrogenase assay after 8 hrs of plasma recirculation. Fg fouling and platelet adsorption on pCB-coated PDMS were 10.40 ± 3.0% of control (

Perfusion safety: past, present, and future.

Safe cardiopulmonary bypass has been paramount from its first use in the early 1950s until the present. The original perfusion circuits incorporated complex feedback loops and multiple safety devices. As circuits improved and became simpler to operate, advances in safety did not always keep pace. Surveys have illustrated areas that needed improvement and extra attention has been focused on those problems. As the field of perfusion evolved, so has the perfusionist. Perfusion has progressed from on-the-job training to formalized training, certification, and accreditation, and is now approaching national standardization. As the computer age proceeds, the use of safety devices and feedback mechanisms whose developments have been aided by the newly available technologies increases. As the 21st century approaches, cardiopulmonary bypass will continue to become safer, but the perfusionist must continue to stay up-to-date in education and remain vigilant while in the operating room

Coronary Artery Bypass Grafting in a Patient with Haemophilia B.

Patients with coagulation disorders present the entire open-heart surgical team with an increased challenge. A patient with a known history of moderately severe Factor IX deficiency (2.4% activity) was evaluated for coronary artery disease. Cardiac catheterization revealed a 99% right coronary artery lesion, a long 99% circumflex lesion and normal left ventricular function. Sextuple coronary artery bypass grafting was performed with the aid of aprotinin and Factor IX transfusions. The patient\u27s platelet count after cardiopulmonary bypass was 65,000/mm3, down from a preoperative level of 172,000/mm3, requiring the transfusion of six units of pooled platelets immediately postoperation. The patient was extubated five and a half hours after arriving in the Intensive Care Unit, and his chest-tube drainage after the first 24 hours was 373 ml. Other than a transient episode of atrial fibrillation on the third postoperative day, the patient had an uneventful postoperative course and was discharged on the sixth postoperative day. With the use of aproptinin and the newer monoclonal antibody-purified Factor IX concentrates that have been developed, many of the added risks of performing open-heart surgery on patients with haemophilia B are greatly reduced if not eliminated

The Effect of Fast-Tracking on Neurological Complications Post-Cardiopulmonary Bypass.

With the push to get patients through the system in five days, most patients undergoing nonemergency coronary artery bypass grafting (CABG) are being fast-tracked\u27. Using this anaesthetic regimen appears to keep patients less anaesthetized (light) during cardiopulmonary bypass (CPB) than when using our previous regimen. This is manifested by higher mean arterial pressures (maintained above 65 mmHg) during CPB. If patients are receiving less anaesthesia during CPB, they may have an increased cerebral metabolism. This could lead to decreased cerebral oxygenation with a resultant neurological deficit postoperatively. A retrospective analysis of 200 patients who underwent nonemergency CABG was conducted to evaluate postoperative neurological complications. The patients were matched by surgeon, procedure and CPB time. They were separated into two groups: group 1 had maintained mean arterial pressures greater than 65 mmHg on CPB (n = 100) and group 2 had pressures less than 65 mmHg (n = 100). Group 1 had two patients (2%) who exhibited neurological complications after CPB (delirium, continuous coma for at least 24 h) with both of these patients previously having noted cerebrovascular disease. Group 2 also had two patients (2%) with postoperative neurological complications (delirium, transient stroke) with one patient having cerebrovascular disease. From our study, we cannot say that fast-tracking increases the risk for postoperative neurological complications. This could be due to the fact that we maintained the mean venous oxygen saturation during CPB above 70%. More specific testing needs to be done to truly rule out any negative postoperative effect